Automatic Tray Loader

Abstract

A tray loader for containers in which containers are moved by a continually travelling flat top conveyor belt along a straight line path of travel in turn past a sensor of stationary receptacles, an isolation finger, a first gate, a second gate and a third gate. The isolation finger, the first gate and the second gate can be moved into and out of the path of travel of containers on the belt. The third gate is permanently in said path. Two shallow transport trays, each having an open front mouth, are located with their mouths adjacent the belt, one between the first and second gates and the other between the second and third gates. In operation, at the beginning of a cycle the first gate is in container-blocking position to detain travel of containers with the belt until a single file of abutting stationary containers backs up to the sensor which, upon actuation, moves the isolation finger across the conveyor so as to define a single file string of contacting containers, the length of which is equal to the width of the trays. Thereafter the first gate retracts from container-blocking position permitting the string of grouped containers to move along with the belt, either to the second gate if it happens to be in container blocking position, or to the third gate if the second gate is out of container-blocking position. After the string reaches either the second or third gate a pusher transfers the string of containers transversely off the belt and into the open mouth of the associated tray. After the last container in the string passes the first gate, the first gate moves back to blocking position and the isolation finger moves out of blocking position permitting fresh containers to move with the conveyor to the first gate. This cycle of operations is repeated until one of the trays is filled. Thereupon the same cycle of operations is performed with respect to the other tray by moving the second gate either to blocking or unblocking position, as the case may be. While the string of containers is being blocked by the second or third gate as the conveyor moves beneath them the linear integrity of the string is maintained by parallel members on opposite sides of the string, one of these members being the pusher. The other member moves with the pusher as the string of containers is transferred from the conveyor belt to a tray but is lifted after the containers clear the conveyor belt so as to densely mass the containers on the tray. Optionally, alternate rows of containers transferred into a tray fluctuate in length by one container so as to mass the containers in the tray in a hexagonal, rather than an orthogonal, pattern.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

Automatic multiple tray loader

2. Description of the Prior Art

The instant invention is directed primarily to the loading of containers in an open-mouthed tray to enable the containers to be transferred by hand or machine in such tray to a site of operations where some step will be practiced in connection with the containers. The nature of the step to be practiced is of no importance and might constitute, for instance, sorting, washing, drying, sterilizing, air blasting, steam blasting, filling, testing, capping and labeling of the containers. The containers with which the present invention deals primarily are made of glass or plastic and quite often are round, i.e. not flat-sided.

Heretofore transport trays have been loaded with such containers by hand and, insofar as the inventors are aware, there is no equipment capable of automatically loading such containers onto trays.

Automatic loading equipment for containers, in general, has been proposed but such loading equipment is designed for handling of containers which either are heavy or not slippery, i.e. which will not slide readily with respect to one another when pressed together, particularly when end pressure is exerted on a linear string composed of several such containers. The problem is that where a continuously moving flat top conveyor is employed, and this is desirable for high-speed operations, if a string of containers is halted while the conveyor moves beneath it the linear pattern of the string tends to disintegrate because the lengthwise pressure causes the containers to slide away from one another and thus depart from the linear pattern. Thereafter it is quite difficult to push the containers off the conveyor into loading equipment in a repeatable pattern, specifically a linear pattern, in order to creat a symmetrical array of containers in the loading equipment. An apparatus has been proposed to overcome this particular difficulty, the apparatus comprising a retaining wall which spans the mouth of the loading equipment and is parallel to a pusher wall, the retaining wall being moved downwardly out of the path of travel of the string of containers as the same is swept off a conveyor into loading equipment by a pusher wall. However, the problem with such apparatus is that, at the critical moment when it is desired to maintain a linear pattern for the string of containers, the retainer wall disappears downwardly out of the transverse path of travel of the string, and nothing remains to perform its function, so that the linear pattern of the string disintegrates. Moreover, in previously proposed loading apparatus no provision has been made for switching the loading cycle from one tray to another in order to permit an operator to withdraw a loaded tray and carry it to other equipment while the loading apparatus automatically proceeds to load a second tray.

SUMMARY OF THE INVENTION

1. purposes of the Invention

It is an object of the present invention to provide an automatic tray loader which overcomes the defects of prior loading equipment and makes possible for the first time the automatic loading onto a tray of round plastic and glass bottles whether the same are full or empty.

It is another object of the present invention to provide an automatic tray loader which functions in association with plural transport trays so that after one tray is filled and is being taken away by an operator the loader automatically proceeds to fill another tray, and such cycle continues back and forth between the two trays thereby achieving maximum efficiency of operation with a minimum of manual assistance.

It is another object of the present invention to provide an automatic tray loader for handling round containers in which a channeling guide is provided to maintain the integrity of a linear string of abutting containers as it is halted at a loading station and is being swept off a flat top moving conveyor belt and indeed, until it has left the belt so that the belt does not tend to destroy the linear integrity of the string, such guide moving with a pusher transversely of the string as the string is swept off the conveyor, but lifting up from the string after the string has left the conveyor so that the guide does not interfere with dense packing of each string as it is pushed into a tray against the last string transferred onto the tray.

It is another object of the present invention to provide an automatic tray loader which includes an arrangement for isolating on a flat top moving conveyor belt ahead of a position in which the first of plural trays is located a linear string comprised of a preselected desired number of containers, the string being held stationary on the moving belt until at a certain point in the cycle of operations the leading container, and therefore the entire string, is released to travel down to a position abreast of a tray to which the containers are to be transferred, at which position the leading container, and therefore the string, is halted awaiting operation of a pusher to sweep the string onto the tray.

It is another object of the present invention to provide an automatic tray loader of the character described in which a conveyor belt that moves the string of containers from an isolated position on the belt to a location abreast of a tray moves continuously, that is to say, not intermittently, whereby to obtain a high handling speed.

It is another object of the present invention to provide an automatic tray loader of the character described in which an apparatus for isolating a string of a predetermined number of containers optionally alternately varies by one the number of containers in the string so that when successive strings are swept onto a tray the containers will form a hexagonal staggered pattern.

It is another object of the present invention to provide an automatic tray loader of the character described in which a counter is employed to count the number of strings swept into a given tray and, after a preselected number has been thus transferred which is sufficient to fill the tray, to shift the stopping point for following strings of containers abreast a different tray.

It is an ancillary object of the invention to provide an automatic tray loader in which the trays include movable back stops which tend to maintain the integrity of the pattern of massed successive strings of containers as they are accumulated in the tray.

It is another object of the invention to provide an automatic tray loader of the character described which is simple, rapid and efficient in operation.

Other objects of the invention in part will be obvious and in part will be pointed out hereinafter.

2. Brief Description of the Invention

The automatic tray loader of the present invention is designed to receive containers from any source at an inlet end. The containers may be fed into the loader manually as, for instance, from crates of containers. However, more usually, the containers will be fed into the loader from a preceding machine. This may be a machine of any nature whatsoever and, by way of example, constitutes a sorter in which a randomly arranged mass of containers is fed into a hopper from which the sorter withdraws containers one at a time and arranges them in identical orientation, usually mouth up. Other types of equipment from which the loader can receive containers are a sterilizer, a cleaner, a washer, a filler, a labeller, a tester, or a capper.

The inlet end of the automatic tray loader constitutes the upper reach of a table top, conveyor belt, i.e. a flat top conveyor belt, this reach extending from said inlet end to a sheave, or the like, from which the conveyor belt returns to another sheave which may be at the inlet end or upstream of the inlet end. The conveyor belt may be a part of the preceding piece of equipment.

A guide channel is provided at the inlet end, said channel constituting a pair of parallel upstanding walls which, with the table top conveyor belt, defines a linear path of travel for containers leading into the loader from the inlet end. The upstanding walls are spaced apart a distance slightly in excess of the transverse dimension of containers to be loaded so that, as the conveyor belt moves the containers away from the inlet end, the containers are in a single file, that is to say, not abreast of one another.

The conveyor belt first moves the containers past a sensor of the type which is able to determine the presence of a stationary container adjacent the sensor in the guide channel. The sensor mechanism may be a photoelectric cell located on one side of the channel and a source of light on the other side of the channel, or it may be an air nozzle that directs a jet of air across the channel so that when a container is close to the nozzle the pressure of air upstream of the nozzle rises, or it may be lightweight finger which extends into the channel and is pushed back by containers as they move past the finger. Thus, each time a container moves past the sensor there is a change in condition of the sensing element. The sensor, moreover, includes a short-span timer, which may be an integrator, that will detect the continued presence of a container stationary at the sensor for a short period of time such, for instance, as the time it would require for a few containers to pass the sensor. As will be apparent subsequently, if a container is stationary at the sensor for such a short period of time, it is an indication that a container downstream of the sensor has been blocked and that there has been a backup of containers with container after container coming to a halt while the conveyor belt moves thereunder until, finally, the string of stationary containers in the guide channel has reached the sensor, thus indicating that from the sensor to a downstream blocking means (subsequently described) there is a linear file of abutting, i.e. contacting, containers.

The conveyor belt, after it leaves the sensor, moves past an isolation finger. This finger is mounted for transverse movement under the control of a moving means into and out of the guide channel between an extended (actuated) position in which it blocks movement of containers along the channel as the conveyor belt continues to move beneath them and a retracted (idle) position in which this finger is clear of the channel so as to permit travel of the containers past the finger with the conveyor belt. The isolation finger is provided with an adjustable mounting which permits its position to be selectively varied parallel to the direction of travel of the conveyor belt for a certain purpose later described.

Downstream of the isolation finger the conveyor belt moves past a first gate which is guided for movement transversely of the guide channel from an extended container-blocking to a retracted container-passing position under the control of a moving means. This first gate is the blocking means hereinbefore referred to which will block a linear file of containers upstream of the stationary-containing sensor. The stationary-container sensor is so connected to the moving means for the isolation finger that as soon as the presence of a stationary container is determined at the sensor, the isolation finger is moved into blocking position and, in so doing, will segregate, that is to say, isolate, a string of a selected number of containers between said finger and the first gate. This number of containers is equal to the number required for a string to fill the width of a tray into which the containers are to be loaded.

After the conveyor moves past the first gate it travels to a second gate and then a third gate. The second gate includes means for moving it between an extended container-blocking and a retracted container-passing position with respect to the conveyor. The third gate is, except as hereinafter mentioned in connection with an alternate embodiment of the invention, fixed in a container-blocking position.

The second gate is in line with the downstream side of a first transport tray and the third gate is in line with the downstream side of a second transport tray. The trays are open topped and shallow and have an open mouth. The trays are disposed on the loader with their open mouths parallel to, facing and close to one side of the conveyor belt and with their bottom walls in substantially the same horizontal plane as the top reach of the conveyor belt so as to be ready to have swept through such mouths successive strings of juxtaposed containers transferred off the conveyor belt and onto the tray in a direction transverse to the direction of movement of the conveyor.

After the string of containers has been isolated, the first gate moves to container-passing position, thus releasing the string for movement downstream with the conveyor belt. When the second gate is in container-blocking position the leading container in the moving string will stop at this gate so that the entire string is abreast of the first transport tray.

On the side of the container remote from the tray a pusher wall is disposed, the same being actuatable by a moving means which can move the pusher wall across the conveyor and into the open mouth of the tray and with it a string of containers whose movement, along with the conveyor belt, is halted by the blocking second gate. Moreover, there is provided parallel to the pusher wall a retaining wall which is on the side of the conveyor belt adjacent the tray. This retaining wall with the pusher wall defines a second guide channel for the moving string of containers released by the first gate and holds the string in linear single file arrangement when blocked by the second gate despite the fact that the conveyor belt is moving beneath them. Without the retaining wall the linearity of the string would disintegrate.

Moving means is provided to move the retainer wall in synchronism with the pusher wall while the pusher wall transfers containers laterally into the open mouth of the tray. However, just before the retaining wall reaches the last transferred string of containers in the tray, said wall lifts vertically so as to clear the space between the last transferred string of containers and the string of containers being freshly transferred into the tray by the pusher wall. Hence, at this last moment, after the containers have left the conveyor belt, the string of containers is forced against the last transferred string of containers in the tray so that a dense packing of containers is obtained. The last swept string of containers pushes the previously transferred strings of containers back into the tray.

After the freshly transferred string of containers is in the tray, the retainer wall which still is in elevated position and the pusher wall which is at the horizontal level of the containers move back toward their starting positions. Then after the retainer wall has cleared the last transferred string of containers it drops down to the horizontal plane of the pusher wall so that as it and the pusher wall come to rest on opposite sides of the conveyor they will redefine the second guide channel for reception or passage of a string of containers.

Each time that the pusher wall is actuated a counter is operated, the counter being set to the proper total number of strings which it is desired to transfer into the first transport tray. When this number has been reached the second gate moves to container-passing position and a pushing operation similar to that described for the first tray is performed for the second transport tray in cooperation with the fixed third gate. When a proper number of pushing operations has been performed for the second tray the second gate moves back into container-blocking position and the cycle of operations is repeated for the first transport tray. Each time a tray is filled an operator carries the same to a desired site for further processing of the containers.

Optionally, the trays may include back stops which are consecutively pushed back each time that a fresh string of containers is pushed into a tray. Such back stop may have a friction drag at its ends on the side walls of the tray and assists in maintaining a regular pattern of containers loaded into the tray.

Desirably, a tray position sensing means is associated with each tray to ensure that a tray is properly positioned at the loading station being currently employed, this sensing means being in circuit with a motive means for the tray loader such, for instance, as a cycling motor whereby the loader will not function unless a tray in the process of being loaded or about to be loaded is emplaced correctly.

For the sake of safety a timer may be connected to the stationary-container sensor to stop operation of the loader in the event that no containers pass the sensor for a period of time which is somewhat more than the time required to complete a container transferring cycle whereby to prevent useless operation of the loader in the event that containers are not fed into the inlet end of this machine.

In the loader as thus far described the number of containers in each string is identical for any given width of transport tray and this will result in an orthogonal pattern of containers as they are loaded into the trays. However, an orthogonal pattern does not make maximum use of the tray area which only is obtained with a staggered, i.e. hexagonal pattern in which adjacent rows include a number of containers which alternately varies by one. The loader of the present invention includes means for performing staggered loading, this means being optionally usable. Such means includes an arrangement for changing the positions of the isolation finger and of the second and third gates with respect to the length of the conveyor belt for each pushing cycle so that when successively alternate strings are formed and pushed into a tray, the number will alternately vary by one.

The banks on the loader which receive the transport trays alongside the conveyor are arranged to be adjustable in width so as to accommodate trays of different widths, and the positioning means for the isolation finger likewise is arranged to be adjustable to make a corresponding variation in the number of containers isolated in each string.

The motive means for the various movable components of the machine, such, for instance, as the isolation finger, the first and second gates, the pusher walls, the retainer walls, the counter for the number of pushes for each tray and the counter for successive pushes in the event that a staggered pattern is to be formed in the trays, can be of any suitable type. For example, these motive means may consist of cams, or linkage systems, or pneumatic or hydraulic cylinders, with associated valves that are operated in proper time sequence either mechanically or electrically, or electromechanical moving means such, for instance, as solenoids which are operated in proper timed relationship by electrical circuitry either with the assistance of cams or timing circuits including, for instance, stepping switches. The basic concept of the invention resides in the assemblage of means heretofore described, not in the particular mechanisms utilized to actuate these means.

The invention accordingly consists in the features of construction, combination of elements, arrangements of parts and series of steps which will be exemplified in the devices hereinafter described and of which the scope of application will be indicated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings in which are shown various possible embodiments of the invention:

FIG. 1 is a perspective view of an automatic tray loader constructed in accordance with and embodying the present invention and also illustrating a preceding container-handling mechanism the output of which is connected to the inlet end of the loader;

FIG. 2 is a top plan and partially sectionally view taken substantially along the line 2--2 of FIG. 1 and schematically showing certain components of the loader; in this figure the loader is shown in that portion of the cycle in which the isolation finger and first gate are in container-blocking position so as to segregate a string of containers composed of a preselected number thereof and the preceding string of containers has arrived at and is blocked by the fixed third gate while the pusher walls and retaining walls of both loading stations are in idle condition, previously transferred strings of containers being in place in the second tray;

FIG. 3 is a view similar to FIG. 2 but illustrating the pusher wall and retaining wall of the section station in their extended positions and with the retaining wall lifted so that the last transferred string of containers abuts the previously transferred string of containers which has been pushed further into the tray thereby;

FIG. 4 is a view similar to FIG. 2 but illustrating the loader with the second gate in container-blocking position so that the first tray is about to be filled;

FIG. 5 is an enlarged fragmentary sectional view taken substantially along the line 5--5 of FIG. 2 and showing, inter alia, the moving means for the pusher and retaining walls, said walls being illustrated in their idle positions;

FIG. 6 is a view similar to FIG. 5 but showing the pusher and retainer walls in their extended positions and the retaining wall elevated;

FIG. 7 is an enlarged fragmentary sectional view taken substantially along the line 7--7 of FIG. 2;

FIG. 8 is a fragmentary view showing the friction drag means for the ends of a back stop in one of the trays;

FIG. 9 is a cycle diagram for the automatic tray loader; and

FIG. 10 is a fragmentary view of a tray partially loaded with containers arranged in a staggered pattern.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now in detail to the drawings, and more particularly to FIG. 1, the reference numeral 20 denotes an automatic tray loader constructed in accordance with and embodying the present invention. The tray loader has an inlet end 22 which is upstream from the various other components of the loader hereinafter described. Containers C are fed into the inlet end in any manner well known in the art. For example, they may be placed in the inlet end by hand, or they may be introduced into the inlet end from a preceding machine 24. Said machine may be of any known type which performs a conventional function upon the containers C. Typical such functions are sorting, washing, drying, sterilizing, air blasting, steam blasting, filling, testing, capping and labeling. Customarily in performing any of these operations in a standard machine, the containers leave the machine in a predetermined orientation which, pursuant to the present invention, desirably is mouth up.

The inlet end 22 constitutes an open top U-shaped guide channel defined by parallel upright side walls 26 and a bottom wall. The bottom wall is the top reach of a conveyor belt which extends from the inlet end to the far downstream end of the loader 20 where it is trained about a sheave 28 to lead to the bottom reach (not shown) which returns to another sheave (not shown) which may be located in the preceding machine 24. The specific type of conveyor belt 30 used in the present invention is of table top configuration, which is to say flat top configuration, and which for drive purposes has its undersurface formed with teeth 32 that are in mesh with a power driven gear 34. In order to impart horizontal stability to the upper reach of the conveyor belt, and to prevent this reach from shifting tranversely, in the form of the invention illustrated said reach travels in a shallow trough 36 formed in a top platen 38. The trough traverses the platen from side to side. Thus, any containers present at the inlet end 22 of the loader will be moved by the conveyor belt 30 across the top platen so far as the containers are permitted to do so. If containers are blocked by any of various elements which will hereinafter be detailed, the conveyor belt will move beneath the containers; that is to say, it will slide beneath the containers while the containers remain stationary.

It should be observed that the containers which the loader is designed to operate upon preferably are of non-linear cross-sectional contour; in other words, are round, i.e. circular, or at least largely rounded. The problem with such containers, particularly glass or plastic containers which are inherently slippery, is that when they are blocked on a belt that moves beneath them, as a linear file of containers held up by a leading container grows longer, the lengthwise pressure on the file which, in reality is a column, will tend to buckle the file. It will be seen hereinafter that this problem is avoided by a feature of the present invention.

The side walls 26 lead from the inlet end 22 to slightly past the upstream edge 40 of the platen 38. These side walls are essentially continuous. The discontinuities therein which will soon be described are so short as to be negligible so that said side walls act to constrain the containers moving between them, while the belt moves under or with the containers, whereby the containers remain in an essentially straight line. The side walls are spaced apart a distance slightly greater than the diameter of the containers in order to maintain longitudinal integrity of the file of containers, and preferably the spacing between the side walls is such as not to permit two containers to travel abreast. Inasmuch as the loader is preferably useful with containers of different diameters, screw-type adjusting means 42 are included for varying the spacing between the side walls.

As mentioned previously, there are plural discontinuities, i.e. openings, of narrow width, at points spaced lengthwise of the conveyor belt, each discontinuously having a width less than the diameter of the containers so as to prevent escape of containers from the guide channel. The first of these discontinuities, downstream of the machine 24, constitutes an opening 44 which collaborates with a sensor 46.

The sensor is responsive to the presence of a container at its station on the conveyor. More specifically, the sensor is responsive to the presence of a stationary container at its station on the conveyor. That is to say, the sensor not only senses the passages of a container through its station, but furthermore senses when a container is stationary at the station for a preselected short period of time, for example, in the neighborhood of one-half second to a second. Thereby, the sensor will detect the blocking between the side walls 26 of a container downstream from the sensor which causes a backup of stationary containers that reaches upstream to the sensor.

The sensor includes any suitable arrangement which is actuated by the presence of a container stationary at or moving past the sensor. For example, one such sensing arrangement is a finger which is lightly spring biased into the channel formed by the side walls 26 and conveyor belt 30, and which is forced outwardly by the presence of a container at or moving past the sensor. Such movement of the finger will close a switch in an electric circuit to create a pulse. The pulse is fed into an integrator which evaluates the width of the pulse, this being a function of the time that the container is at or moving past the sensor. If the integrator determines that such time exceeds a predetermined time that is greater than the time required for the container to pass the sensor the integrator generates a signal which denotes that a container has been at the sensor longer than it takes a container to pass the sensor moving at the speed of the conveyor belt. This, therefore, is a signal that there has been a blockage of containers on the conveyor belt downstream of the sensor 46.

In the specific embodiment of the invention here shown the sensor 46 constitutes a nozzle 48 and an air pressure-sensitive switch 50. Air under pressure is directed into the guide channel across the path of travel of containers on the conveyor belt. The switch is set to generate a pulse when a container passes the nozzle and builds up a back pressure that triggers the switch 50. When the air jet plays between adjacent containers, even though they are touching, no pulse will be generated since the air back pressure in the switch will not build up because the flow of air out of the nozzle is not blocked by a nearby container. This pulse is, for containers moving with the conveyor belt, of very short duration. In an exemplificative loader 20 the belt is set to move at about seven containers per second. Therefore, there will be approximately seven pulses per second generated by the sensor 46. It will be understood that this particular rate is in no wise limitative and has only been mentioned by way of example.

If the pulse continues (stretches out) for a predetermined period of time, e.g. one-half second to one second, longer than it takes a container to move past the sensor, a signal will be generated. To create this signal the output from the sensor is conducted by a lead 52 to an integrator 54 which may be an RC charging circuit or a clock for measuring the time width of the switch pulse. The integrator will issue a signal when the pulse from the switch continues for a predetermined period of time sufficiently long to ensure that a container is stationary at the sensor.

The next of discontinuities in the aforesaid guide channel formed by the side walls 26 and the conveyor belt 30 is at an isolation finger 56, preferably having a pointed tip. The isolation finger is mounted for movement thwartwise of the guide channel, and is designed to be moved from an extended position as shown in FIG. 2, to a retracted position in which it is clear of the said channel. The side walls 26 are formed with openings to permit such movement of the isolation finger. As illustrated, both side walls include such openings. However, it is only necessary for there to be an opening in one of the side walls for the finger to extend into said channel. It is not necessary for the finger to extend completely across the channel, it merely being imperative for the purpose of the present invention that the finger be able to extend far enough into the channel for it to block containers moving from the sensor to and past the isolation station where the isolation finger is located. It should be mentioned that although in the preferred form of the invention the isolation finger moves horizontally thwartwise of the path of travel of the containers, it is also contemplated that the isolation finger move from a position above a moving stream of containers on the conveyor to a lower position in which the finger extends far enough between the walls 26 to separate containers upstream thereof from containers downstream of the finger.

Means further is included to move the isolation finger from its operative (blocking) position to its idle (non-blocking) position.

As will be described later in detail in connection with the various parts of the loader 20, certain of such parts reciprocate. Such reciprocation can be achieved by any well known type of motive means, i.e. actuating means, to wit, means which will move a part back and forth between two positions. One suitable means is a purely mechanical means exemplified, for instance, by linkages actuated by cams or cranks from a rotary shaft or by pusher rods actuated by cams from a rotary shaft. The same type of motion, i.e. reciprocating motion, can be obtained hydraulically, to wit, with the use of hydraulic cylinders, or pneumatically with the assistance of air cylinders, this latter being the type herein illustrated. Still another motive means may constitute solenoids, a different one for each different reciprocal movement desired. As shown in the machine of the present invention, the various parts are moved between their two extreme positions pneumatically, i.e. with the use of pneumatic cylinders having pistons traveling therein, the opposite ends of the cylinders being respectively alternately exposed to high pressure and atmosphere by suitable valving. The valving can be purely mechanically operated, or, as here shown, is operated electromechanically, e.g. by solenoids with return springs. Inasmuch as solenoid-operated valves are in widespread use, no specific description thereof will be given in connection with the instant loader.

Thus, the actuating means for the isolation finger 56 constitutes a cylinder-and-piston 58, the piston having attached to its rod 60 the finger 56. One end of the pistons connected by a conduit 62 to a port of a four-way valve 64, and the other end of the piston connected by a conduit 66 to a diametrically opposed port in said valve 64. The valve also has diametrically opposed ports 90.degree. away from those ports to which the conduits 62, 66 are connected, the latter ports being connected respectively to conduits 68 and 70. The conduit 70 is connected to a main 72 containing a source of air under pressure, and the conduit 68 runs to the ambient atmosphere. Accordingly, as is well known, when the valve 64 is in one of its two positions, it connects the conduit 70 to the conduit 62, and forces the isolation finger to its blocking position illustrated in FIG. 2, while the other end of the cylinder is connected through the valve to the exhaust conduit 68. When the integrator 54 generates a signal and the signal is applied to the electromechanical actuator (solenoid) for the four-way valve via lead 74 having a normally closed latching relay switch 75 series connected therein, said valve is positioned to make the aforesaid connection. When the signal is not present, the valve returns to its idle position under the bias of a spring (not shown) which connects the pressure conduit 70 to the conduit 66, and the exhaust conduit 68 to the conduit 62, thus retracting the isolation finger.

The cylinder-and-piston 58 are mounted in a manner later to be described which permits the isolation finger and cylinder-and-piston 58 to be shifted longitudinally in a direction parallel to the guide channel by an increment equal to the diameter of one container of multiples thereof, this adjustment being by hand. Moreover, optionally, the mounting is such that upon receipt of an electrical signal the isolation finger is shifted longitudinally by the width of one container, alternately moving in an upstream and a downstream direction, so that the finger is in a different position alternately for each successive pushing cycle of the loader.

The next element downstream on the conveyor belt, i.e. downstream of the isolation finger 56, is a first gate 76 which is arranged to enter into or to move out of the guide channel, transverse openings, or at least one opening, being provided in the side walls 26 to permit said first gate to move from a retracted idle position in which it does not block the said channel to an extended actuated position in which it blocks the said channel to prevent movement of containers in a downstream direction past it. The first gate occupies a position which is fixed longitudinally with respect to the aforesaid channel, although as just noted, the first gate can move transversely between container-blocking and container-unblocking positions for containers being carried by the conveyor belt 30.

The means for reciprocating the first gate 76 is of the same structural type as that for transversely reciprocating the isolation finger, to wit, it constitutes a cylinder-and-piston 78, the piston rod 80 lying perpendicular to the direction of travel of the belt, and having the first gate 76 connected to its free end. Conduits 82, 84 lead from opposite ends of the cylinder to diametrically opposed ports on a solenoid actuated spring-return four-way valve 86 having another pair of diametrically opposed ports spaced 90.degree. away from the first-named ports and connected to pressure and exhaust conduits 88, 90, respectively. The pressure conduit is connected to the pressure main 72.

When the valve 86 is in one position (pressure to conduit 82 and exhaust to conduit 84) the first gate 76 is in the extended blocking position illustrated in FIG. 2. When the plug of the valve is rotated 90.degree. (pressure to conduit 84 and exhaust to conduit 82) the first gate is moved to its idle non-blocking position by the return spring of the solenoid. The solenoid of valve 86 is actuated by a signal passing through a lead 92 from a normally open momentary switch 94, the actuating finger of which is operated by a cam 96 on a cam shaft 98 driven by an electric motor 100 powered from a source of electric supply 102. When the switch 94 is open, i.e. when the actuating finger of the switch 94 is not engaged by a rise on the periphery of the cam 96, the spring associated with the solenoid of the valve 86 holds the valve in such a position as to supply pressure to the conduit 84 and ambient atmosphere to the conduit 82 so that the finger 76 will be retracted to its idle non-blocking position. When a rise on the cam 96 engages the actuating finger of the switch 94, the valve is turned by its then-actuated solenoid to a position in which high pressure air is supplied to the conduit 82 and the conduit 84 is connected to the atmosphere, so that the first gate 76 then will be extended to its blocking position and held there so long as the rise engages the switch finger. The timing for this cam in operation, and indeed for the other cams and their operation, will be described later.

At the same time that the switch 94 is actuated by the cam 96 a normally open momentary switch 95 is actuated by a cam 97 on the shaft 98 to send a signal over a lead 99 to the unlatching solenoid of the switch 75 so as to cause said switch 75 to open and break the lead 74 whereby as the first gate 76 extends the finger 56 retracts despite the presence of a stationary container at the sensor 46. The switch 94 remains closed for a very short period of time and then reopens to permit the switch 75 to close and restore the finger 56 to the control of the sensor 46.

The conveyor belt 30 as it crosses platen 38, moving in the trough 36, travels past plural loading stations, herein shown as only two loading stations, by way of example. There is an upstream loading station 104 and a downstream loading station 106. Each station is so designed that it will removably receive a transport tray 108. There is at least one transport tray for each loading station. More than one can be provided, if desired, depending upon the spacing between the physical location of various equipment in the factory at which the locator is used. Each loading tray includes a flat horizontal bottom wall 110, a rear wall 112, and parallel side walls 114. All the walls are fixed and, optionally, of the same height so as to form, where they are located, a perimetral boundary. However, there is no wall at the front (mouth) of the tray, and the top of the tray likewise is open. The trays are intended to be disposed with their open mouths facing one side of the conveyor belt as it crosses the platen 38 and with the front edges of the trays at the mouths close to or even immediately adjacent one lateral edge of the belt, hereinafter referred to as the "off" delivery edge 116. The front edges of the tray are in mutual transverse alignment and parallel to the off edge 116.

Suitable guiding means is included to locate the transport trays in their correct positions. The guiding means for both trays are identical except for their siting upstream and downstream of one another, i.e. at two different loading stations 104 and 106, so that only one tray guiding means will be detailed.

At the downstream edge of the desired position of the loading tray, a stationary rail 118 is fixedly, non-movably attached to the platen 38, this rail running perpendicularly from near the off delivery edge of the belt to the front edge 120 of the platen 38. Abutment of the outer surface of the downstream wall 114 of a transport tray against the upstream surface of the rail 118, correctly locates the associated transport tray longitudinally of the conveyor belt with respect to the platen 38.

An upstream corresponding rail 122 parallel to the rail 118 is provided for each loading station. However, this rail 122 is bodily shiftable in a direction longitudinally of the conveyor belt 30 in order to be able to accommodate transport trays of different widths. This is desirable both for adjusting the loader to receive transport trays that hold containers of different diameters, and that hold different numbers of containers in each row of containers to be carried by the tray. The adjusting means conveniently comprises a pair of screws 124 freely extending through vertical openings in the rail 122 and having heads larger than said openings. The threaded screw shanks, after extending through such openings, extend through platen slots 126 which are parallel to one another, and run in a direction parallel to the direction of travel of the conveyor belt. The tips of the threaded shanks project beneath the platen 38 where they receive wing nuts (not shown) thereby to permit the screws and rail 122 to be tightened in any adjusted position for any selected width of transport tray that will slidably accommodate breadthwise a linear row of a specific number of containers of a specific diameter.

Means is included to limit movement of the transport tray toward the off edge of the conveyor belt 30 so that the front edge of the tray will be spaced slightly from the conveyor belt and occupy a predetermined position. Such means conveniently is in the form of a ledge 128 (see FIGS. 5 and 6) against which this edge of the transport tray is designed to abut when the tray is moved inwardly toward the belt between the pair of rails 118, 122. The top surface of the bottom wall of the tray is level with the top of the ledge as indicated in the above figures, in order to permit an unobstructed movement of containers from the conveyor belt 30 onto the tray when the pusher means, now to be described, is operated.

Each loading station 104, 106 has associated with it pusher means and cooperating file maintaining means, both such means being identical for the two stations, so that only one will be described. A typical pusher means constitutes an upright rectilinear pusher wall 130 arranged alongside of the edge of the conveyor belt remote from the off edge 116. The length of the wall 130 is approximately equal to preferably the diameter of one container shorter than the transverse width of the tray between the inner surfaces of the side walls 114 thereof. The bottom edge of the wall 130 is slightly above the conveyor belt, as can be seen in FIGS. 5 and 6.

In its retracted position, i.e. idle position, as illustrated in FIG. 5, the inner surface of the pusher wall 130 is adjacent the rear edge of the conveyor belt 30. Preferably, this surface is spaced somewhat inwardly of the aforesaid edge of the conveyor belt, so that it is very near to the string of containers C that moves along with the conveyor belt, or beneath which the conveyor belt moves when the string of containers is stationary.

The pusher wall is actuatable by suitable motive means to be moved between the idle first position indicated in FIG. 5 to an extended second position shown in FIG. 6. During its movement from its first to this latter position the pusher wall is swept completely across the width of the path of the containers moved by the conveyor belt and the surface of the pusher wall facing the tray is also swept across the front edge of the open mouth of the tray; thereby any containers which at the time of the idle position of the pusher wall are located abreast of this wall, will be pushed into the mouth of the transport tray. Actually, as will be described hereinafter, the pusher wall pushes into the transport tray a number of linearly arranged containers (hereinafter a "string" of containers) such that the overall length of the string is equal to or very slightly less than the width of the transport tray.

The motive means for the pusher wall 130 constitutes a cylinder-and-piston 132 which is caused to move back and forth, i.e. between idle and actuated position, by a solenoid operated four-way valve 134, which is spring-returned to idle position of the pusher wall, and the solenoid of which is actuated by closure of a normally open momentary switch 136, the actuating finger of which cooperates with a cam 138 on the cam shaft 98. The opposite ends of the cylinder are alternately connected between pressure and atmosphere in the manner already described in detail with respect to previous cylinders-and-pistons.

As has been observed in the brief description of the invention, a string of containers having a desired number and having an overall length equal to slightly less than the width of the transport tray is halted athwart and in registry with the open mouth of the tray, while the conveyor belt continues to move beneath this string. The means for halting the string will be described later. When the halting means is operable the conveyor belt acting on all of the containers by frictional engagement with the bottoms thereof press the containers against the halting means, and, since the containers quite often are round, and, if of glass, slippery, and if of plastic, light and slippery, the string of containers which, in effect, is, at this time, a column of balanced rounded elements under longitudinal compression, tends to bulge away from linearity in a direction away from the pusher wall which prevents bulging in that direction. Actually, a string of containers blocked on a conveyor belt with the pusher wall on one side of the string will quickly lose its linear integrity with the containers falling out of line in a direction toward and into the tray. This would negate one of the features of the invention which constitutes the principle of sweeping a linear string of containers transversely off a conveyor belt that moves beneath them while the string is held stationary on the belt, and, while doing so, maintaining linear integrity of the string, so that as the string is pushed into the mouth of the tray which is stationary, such string can be moved into parallel relationship with previously transferred strings. If the string lost its linear integrity, the containers transferred into the transport tray would, when they contacted previously transferred containers, be arranged in a non-orderly fashion which would not lend itself to subsequent quick discharge of containers from the transport tray to an apparatus which is designed to handle the containers at a later stage of operation and which would not make best usage of the available area of the tray.

To avoid this problem, a file maintaining means is included in the loader 20. Said file maintaining means constitutes an upright retaining wall 140 shown in idle (starting) position in FIGS. 2 and 5. This retaining wall is located above the off edge of the conveyor belt in registry with the pusher wall 130. The retainer wall is parallel to the pusher wall and in idle position is spaced from the pusher wall by a span which barely exceeds the diameter of the containers being handled by the loader. Suitable adjustment means (not shown) may be included to vary the idle position of the retaining wall with respect to the pusher wall for accommodation of containers of different diameters. The downstream edge of the retaining wall is transversely registered with the downstream edge of the pusher wall and is slightly inside (preferably a little more than a container radius inside) the line of the inner surface of the downstream side wall 114 of the associated transport tray. The upstream edge of the retaining wall is in similar relationship with the inner surface of the upstream wall 114 of the associated transport tray and with the corresponding edge of the p usher wall, whereby to permit both these walls to fully enter the mouth of the tray in their extended positions soon to be described.

Motive means is included to cause the retaining wall 140 to experience a closed box movement, this constituting (considering the idle position as a starting point) movement of the retaining wall away from the conveyor belt and into the mouth of the tray, such movement being in a horizontal direction followed by movement of the retaining wall vertically upwardly in an amount sufficient to clear the mouths of the containers in the string which has just been swept off the conveyor belt and then horizontally retrogradely back to a position vertically above idle position and finally back to idle position. As in the case of all other simple reciprocating motions described herein this compound motion can be accomplished with the aid of various types of mechanisms, e.g. purely mechanical, electromechanical, electrical, hydraulic and pneumatic.

A particular means shown for the aforesaid purpose is the same as other means previously described, to wit, electropneumatic. A fixed horizontal cylinder-and-piston 142 is provided, being located on the side of the pusher wall remote from the off edge of the conveyor belt. The piston of this arrangement is secured by a piston rod 144 to a vertical cylinder-and-piston 146. The piston rod 148 of the cylinder-and-piston 146 is fixed to the retaining wall 140. The two cylinders-and-pistons 142, 146 are connected by conduits to four-way valves such as those previously described which enable the opposite ends of the cylinders to be selectively connected to pressure and the ambient atmosphere under the control of solenoids with return springs. The two solenoids are actuated by normally open momentary switches 150, 152, the switch 150 controlling the horizontal cylinder-and-piston 142 and the switch 152 controlling the vertical cylinder-and-piston 146. The switches 150, 152 are arranged to be actuated by cams 154, 156, respectively, on the cam shaft 98. When the two switches are idle, and their corresponding solenoids therefore deactuated, the return springs return the two pistons to positions such that, as shown in FIG. 5, the retaining wall 140 is in its idle (starting) position both horizontally and vertically on the side of the conveyor belt 30 opposite from the pusher wall (near the off edge 116). When the momentary switch 150 (horizontal) is closed, while the momentary switch 152 (vertical) remains open, the retaining wall 140 will move into the mouth of the associated transport tray while remaining in its original horizontal plane. The timing of the cam 154 for the horizontal momentary switch 150 is synchronized with the timing of the cam 138 for the pusher wall, so that the pusher wall 130 and the retaining wall 140 will move in unison into the mouth of the tray, carrying with them a string of containers, while maintaining the linear integrity of said string.

The cam 156 which controls the operation of the momentary vertical switch 152 is so set that it will lift the retaining wall 140 after a string of containers has left the conveyor belt and is on a stationary portion of the loader, either the platen 38 or the bottom wall 110 of the associated transport tray or bridges the two. At this time the retaining wall serves no further function since the string of containers no longer will collapse due to endwise pressure on the string exerted by the moving conveyor belt, and indeed, interferes with proper loading of the string of containers into the transport tray, because it prevents abutment of the string being transported with the previously transferred string. Hence, the cam 156 for the vertical momentary switch 152 is so timed that it will lift the piston of the cylinder-and-piston 146, and with it the retaining wall 140 once the string of containers has cleared the conveyor belt. This will leave a space between the strings of containers being transferred and the previously transferred string. However, while the retaining wall is being raised, and after it is raised, the pusher wall 130 continues its travel under the influence of the cam 138, so as to close this gap between the last transferred and newly transferred strings of containers. Thereafter, i.e. after the pusher wall has reached its fully extended position, both cams 138 and 154 allow the switches 136 and 150 to open, causing the return springs to retract the pistons of the horizontal cylinders which, in turn, causes the pusher wall and retaining wall to move back to idle positions, although at this time the retaining wall is still elevated. Finally, the cam 156 deactuates the switch 152 permitting the return spring associated with the vertical cylinder valve to lower the retaining wall 140 to its idle starting position in the same horizontal plan as the pusher wall, ready to control the next string of containers.

Reference previously has been made to halting, i.e. blocking, means, which is associated with each loading station. Said blocking means for the upstream station 104 constitutes a second gate 160 which is movable from an idle retracted position shown in FIG. 2, to an operative extended position shown in FIG. 4. When in operative position the second gate extends completely across the conveyor belt in line with the downstream side of the associated tray, and will be in the path of a leading container of a string of containers moving along with the conveyor belt from the first gate 76.

Suitable means is included to move the second gate 160 between its two positions, such means comprising a cylinder-and-piston 162, which is pneumatically operated under control of a four-way valve 164 which is spring-biased to idle position. The four-way valve 164 is regulated by a two input counter 166 which counts the number of pushes transferring a string at a time into one or the other of the transport trays, the counter being fed signals from one or the other of normally open switches 168, 170, the first being associated with the upstream loading station 104 and the second with the downstream loading station 106. One or the other of the momentary switches thus will count the number of pushing cycles for any given pusher wall 130. After a preselected number of pushing cycles has been completed, the preselected count will be reached on the counter 166 which then will proceed to energize or de-energize the solenoid for the four-way valve associated with the first gate 160. When the solenoid is energized the second gate 160 will move into its container-blocking position, and thereafter for a predetermined number of pushing cycles the second gate will remain in that blocking position permitting string after string of containers to be halted in their movement by abutment of the leading container against said second gate. After a preselected number of strings has been transferred into the upstream transport tray and the upstream switch 168 actuated that number of times, the counter 166 will de-energize the solenoid, the return spring of which will operate the valve 164 and reverse the application of pressure and atmospheric pressure to the piston of the cylinder-and-piston 162, causing the second gate 160 to move back to its retracted idle position illustrated in FIG. 2.

Thereafter containers will move past the upstream loading station 104 with its pusher and retainer walls in idle position at the time of such passage to the downstream loading station 106, where the leading container of string after string will, before the strings are pushed into the downstream transport tray, be blocked by a third gate 172 which permanently extends across the conveyor belt. This third gate is considered to be fixed, although it subsequently will be pointed out that its position in a direction longitudinally of the conveyor belt can be shifted by one-half the diameter of the container when it is desired to arrange transferred strings of containers in a hexagonal pattern rather than an orthogonal pattern on the associated transport tray. After a preselected number of pushing cycles has been performed, causing the downstream switch 170 to be actuated a corresponding number of times, the total count would be registered in the two input counter 166 which will then, through the valve 164, reverse the application of pressure and ambient atmosphere to the cylinder-and-piston 162, causing the second gate 160 to extend out to blocking position, whereupon a filling cycle for the upstream loading tray commences.

The loader 20 operates as follows: At the start of a cycle, indicated by the reference character I on the cycle diagram of FIG. 9, certain conditions prevail as a result of operations carried out during the previous cycle. The performance of these operations will be described in their proper place in a typical cycle. Suffice it to note at this point that at the 0.degree. position of the cycle the following conditions prevail: Containers C have been placed on the conveyor belt 30 at the inlet end 22 of the loader. The containers have moved past the sensor 46 and past the isolation finger 56. The first gate 76 is in blocking position extending across the conveyor belt. A row of containers has accumulated behind the first gate, being held stationary on the conveyor belt that is moving beneath them. The isolation finger 56 is in its actuated position extending across the conveyor belt, so that between the isolation finger and the first gate there is a string of segregated containers arranged in a line between the walls 26, the number of containers in the string being equal to the number of containers that the transport trays are designed to receive abreast, i.e. from side to side. Moreover, there are stationary containers upstream of the isolation finger 56 extending at least to the sensor 46 which has caused said finger to be shifted to segregating position athwart the guide channel. The motor 100 is turning the cam shaft which revolves once for each string-loading cycle of operations.

The first event to transpire, and which takes place at the 0.degree. position I, is that the cam 96 opens the switch 94 to deactuate the solenoid associated with the valve 86, thereby permitting the spring which is a part of the valve to turn the valve to a position such that it retracts the first gate 76. This permits the string of containers previously isolated between the finger 56 and the first gate 76 to move downstream along with and at the same speed as the conveyor belt, the finger 56 remaining in blocking position to hold back the containers upstream of said finger. At this time it will be assumed that the counter 166 is in such position that the finger 160 is in its idle position, thereby permitting the string of containers to move until the lead container of the string strikes the third gate 172, as shown in FIG. 2, which is permanently across the conveyor belt. It will be appreciated that the second gate 160 might have been in extended position, and that the lead container then would have encountered the second gate to stop the string abreast of the upstream transport tray as shown in FIG. 4. However, with the second gate in retracted position the string of containers will pass by the second gate and continue on to stop abreast of the downstream transport tray.

After the trailing container in the string of containers moving downstream has cleared the first gate 76, said gate 76 moves in at position II the setting of which is timed for such clearance, taking into account the speed at which the conveyor belt is continually moving. The cam 96 causes the valve 86 to actuate the cylinder-and-piston 78 and force the first gate 76 back into blocking position. Concurrently therewith, the cam 97 through the switch 95 associated with said cam, sends a signal along the lead 99 to the unlatching solenoid of the relay 75 to open the circuit 74 of the solenoid for the valve 64 and permit the spring for said valve to reverse the position of the finger 56, causing it to move to its retracted position, so that the stream of containers previously blocked by the finger 56 starts to flow afresh downstream with the conveyor belt toward the blocking first gate 76. The cam 97 holds the switch 95 closed only long enough for the flow of containers to start moving past the sensor 46 and then allows the switch 95 to open so that the lead 74 is reclosed placing the valve 74 back under the control of the sensor which, now that the containers are moving past it, will not move the finger 56 to extended position. Subsequently, at any indeterminate point preceding return to position I on the string-loading cycle of the machine, i.e. the start of said cycle, the leading container of the stream of containers on the conveyor belt moving down the inlet channel will strike the blocking first gate 76, the sensor 46 will be actuated, and the isolation finger 56 will be thrust across the inlet channel to isolate the required number of containers between the finger and the first gate. These steps of actuating the sensor 46 and moving the isolation finger into segregating extended position are not timed, except for the cam 97 which is set to operate at position II.

The cycle is set to provide sufficient time for the leading container of the string to move all the way downstream, to the third gate 132 upstream of which the string then is halted; this will also permit the leading container in a shorter period of time to move downstream to strike and come to rest against the second gate 160 upstream of which the string is then halted, if that gate happens to be in blocking position. Whether the second gate is in blocking or unblocking position will depend upon the state of the counter 166 which determines which of the upstream or downstream transport trays is being loaded.

At position III sufficient cycle time has elapsed to permit such travel of the string. At said position III the cams 138 and 154 will actuate their associated four-way valves to cause both the pusher wall 130 and the retainer wall 140 to start their horizontal movement toward and into that transport tray which then is being loaded. The horizontally reciprocating pistons-and-cylinders 132, 142 are of constructions well known to the art such that they move slowly in a direction toward their extended position, and move back toward idle position rapidly, e.g. the inclusion of dash pots that are principally effective to slow down such extending direction of movement. This is desirable so that the halted string of containers may be gently handles as it is leaving the conveyor belt 30 and being swept into the associated transport tray and can move back quickly when said walls are out of contact with the containers. It will be recalled that during this movement toward and into the tray both the pusher wall 130 and the retainer wall 140 are in a common horizontal plane, i.e. horizontally registered with one another and the halted string of containers, and that these walls define between them a moving channel which nicely accommodates the halted string of containers disposed therebetween and exercises linear control over the string during such transferring movement while the conveyor belt continues to move.

In a typical machine, by the time the point IV in the cycle has been reached, the string of containers will have been swept off the conveyor belt, and it is no longer necessary to keep the retaining wall 140 in position for the purpose of maintaining linear integrity of said string. Hence, in position IV (shown in FIG. 3) the retaining wall 140 starts to rise as the cam 156 closes the switch 152 and operates the four-way valve to a position causing the cylinder-and-piston 146 to lift the rod 148 as shown in FIG. 6. However, the pusher wall 130 continues its off-belt movement under the motivation of the cylinder-and-piston 132 to force the freshly transferred string of containers against the previously transferred string of containers in the transport tray (see FIG. 6). At position V extending movement in a typical cycle of the pusher wall stops because the containers by now have been deposited against the previously transferred string of containers.

Shortly thereafter, at position VI the pusher walls 130 and the retaining walls 140 start to retract upon opening of the switches 136, 150 by the cams 138, 154. Their return move-ment is quite rapid and by position VII the pusher wall has returned to idle position and the retaining wall has returned to above its idle position and has descended to its idle position upon opening of the switch 152 by the cam 156. This descending operation takes place after the retainer wall has moved back far enough to clear the last transferred string of containers. Return of the pusher wall to its idle position actuates the switches 168, 170 (the pusher walls and retainer walls at both loading stations are slaved for similar movement or the walls at either station may be held idle while loading takes place at the other station) which feed a signal to the counter 122 that stores up the number of string-loading (pushing) cycles.

After a proper number of pushes has been fed into the counter 160 a control signal is emitted by the counter to the solenoid of the four-way valve 164 which either moves the second gate 160 into extended container-blocking position if the loading of the downstream tray has been completed, or to retracted container-passing position if loading of the upstream tray has just been completed. The number of counts required to fill the trays is set into the loader by means of selector knobs 174, one for the upstream tray and the other for the downstream tray. The counter 160, for example, constitutes a stepping switch and the selector knobs determine which contact on the switch will actuate the solenoid of the four-way valve 164 for upstream and downstream trays, respectively, inasmuch as for some operations the front-to-back distance of the two trays can be different from one another.

It is desirable to include means automatically to stop operation of the loader preferably at the end of a string-transferring cycle if no containers are being fed to the inlet end 22 of the loader, thereby to prevent useless operation thereof. Such means includes the sensor 46 with a tapped lead 176 taken off from between the lead 52 between the switch 50 and the integrator 54. Thus, a pulse will appear on this lead 176 each time that a container passes the sensor. These pulses are fed to an interval timer 178. When pulses fail to appear in the lead 176 for a preselected period of time, say, 3 seconds, which is longer than the time required to complete a string-transferring cycle, said timer 178 emits a signal which is carried by a lead 180 to a normally open momentary switch 182 having its actuating finger controlled by a single-cycle cam 184 on the cam shaft 98. The single-cycle cam closes the contacts of the switch 182 once each cycle is at the starting position I of the cycle. A lead 186 extends from the switch 182 to a relay 188 having normally closed contacts in series in the circuit running from the source 102 of electric energy to the motor 100. The contacts of this relay are opened when a signal appears in the lead 186. Hence, if no containers move past the sensor 46 for more than the predetermined time, the signal generated by the timer 178 will, at the beginning of the cycle, be transferred by the switch 182 to the relay 188, to open the contacts of the same and shut down the loader. The relay 188 mechanically is of a standard construction which will latch with its contacts in open position, so that the loader will stop until restarted by manually reclosing the contacts of the relay 188.

It also is desirable to include means to ensure that a transport tray is in proper position at a loading station before the loader commences a string-transferring cycle to the tray at that station. For this purpose a relay 190 having normally open contacts is also interposed in the circuit energizing the motor 100 from the source 102 of electric energy. This relay is under control of one or the other of normally open momentary switches 192, the actuating fingers for which are located near the ledges 128 at the two loading stations, so that if the finger at a given loading station is depressed the associated switch will be closed when the corresponding tray is in position. The switches 192 are in two circuits each of which can energize and close the relay 190 which permits the cycle motor 100 to be energized. Each such circuit includes contacts of a different relay 193, the relays being controlled by the counter 166 in such manner that the switch 192 is effective only when strings of containers are being pushed into a tray at the corresponding station.

The loader also includes start and stop buttons 194 and 196 that control another relay (not shown) having contacts in the supply circuit between the source of electric energy and the cycling motor. Gauges 198 on the front panel 200 for the loader indicate the presence of air pressure in the conduits which supply energization for the various pneumatic moving means associated with the loader.

It has been observed that the densely massed pattern of rows and columns of containers formed in a tray as succeeding string-transferring cycles are performed tends to maintain a uniform orthogonal array. However, upon occasion, there is slippage of the containers in the tray as they continue to be pushed rearwardly by successively transferred fresh strings of containers and, as a result, one or more slippage lines will pass through the array. These lines are not inimical to the transport of containers on the tray, but they do create two drawbacks. One is that the loading area of the tray is not fully utilized. This has no dire consequence but is of some significance. The other drawback is that if the containers loaded in the tray are presented to a subsequent handling machine, such machine may be designed to work most efficiently with trays which have the cross rows (strings) of containers presented in linear rows with no breaks therein. The second drawback likewise is not presently of great importance. However, it might become serious depending upon how such subsequent handling machines are designed in the future. Therefore, pursuant to an ancillary feature of this invention, means may be included to minimize the formation of slippage lines in the regular orthogonal array. Such means comprises an arrangement which will maintain the first transferred string of containers in a straight line, thus inhibiting any tendency for subsequent rows of containers to slip transversely and in a front-to-back direction in the tray. More particularly, such means to minimize slippage as illustrated herein constitutes a backstop in the form of a bar 202, one for each tray. Said bar acts as a movable transversely extending linear barrier against which the first transferred string of containers always bears starting from the time that the first string is transferred until the last string is transferred, inasmuch as successive strings push the first transferred row of strings rearwardly against said bar.

The ends of the bar 202 include means for hold the bar in a position substantially perpendicular to the direction of travel of the peripheral wals, and for imparting a light frictional resistance to rearward motion of the bar. To keep the bar in such perpendicular orientation, the bar at the ends thereof includes front and back bosses 204 which slidably ride on the inner surfaces of the side walls 114 of the tray. If desired, the rearmost bosses at opposite ends of the bar can extend rearwardly, as shown, to aid in maintaining such perpendicular position. The frictional drag can be secured in various fashions, for instance, by making the bar sufficiently heavy or by roughening the undersurface of the bar in contact with the upper surface of the bottom wall 110 of the tray, or, as shown, by having undulatory leaf springs 206 located in sockets 208 at opposite ends of the bar, the tips of the undulations frictionally engaging the inner surfaces of the side walls 114. The spring is held under compression with its two ends anchored in slots at the sides of the sockets 208. If the bars are not desired they need not be used or, indeed, need not be furnished with the loader.

As thus far described in detail, the loader only is capable of filling one transport tray and then the other by pushing into the tray being filled one after another linear strings of containers of identical lengths so as to create the orthogonal pattern shown in FIGS. 1, 2, 3 and 4. As above noted, this pattern does not make most efficient use of the space in the tray and also tends to permit the formation of slippage lines, because a mass of articles of circular cross-section always tends to settle into the minimum space that can be occupied by the articles, and since the containers are round and slippery, containers arranged in an orthogonal pattern will, unless held in the pattern under pressure, as by the use of the drag bar 202, ride over one another in spots so that one or more containers in one row will seek to fall between, instead of in line with, containers in a following or preceding row.

Both of these difficulties can be avoided, that is to say, maximum use of the tray area can be made and the tendency to form fault lines eliminated, by operating the loader in such a fashion that the containers as stacked in the tray form a staggered, i.e. hexagonal or beehive, pattern. This is accomplished in the loader of the present invention by having the isolation finger 56 alternately segregate a number of containers in the linear string between it and the first gate 76 in the entry channel which number varies up and down by one; that is to say, a given segregated string of containers has a certain number of containers therein, the next segregated string has one less container, the next the certain number again, the next string one less, etc. Concurrently, the second and third gates 160, 172 are shifted longitudinally of the conveyor belt a distance equal to one-half the diameter of a container, the the shift being downstream for the string of the smaller number and back to the normal position for the string of the larger number.

In order to carry this out, the camming shaft 98 has mounted thereon a stagger cam 210 which controls a normally open momentary switch 212. The stagger cam has only a single elevated portion of slight circumferential width so that it causes the switch 212 to emit a signal of short duration over a lead 214. Said lead runs to a flip-flop switch 216. The flip-flop switch assumes and holds either an open or a closed position in successive string-transferring cycles of the loader, that is to say, when the switch 212 is actuated in one such cycle the switch 216 will move from open to closed, and when the switch 212 is actuated in the next such cycle the switch 216 will move from closed to open, etc. Desirably, the lead 214 includes a manually operated switch (not shown) to optionally render the stagger means effective or ineffective under the control of an operator. Leads 218, 220 and 222 extend from the flip-flop switch 224 to stagger motion devices which control the longitudinal positions relative to the conveyor belt of the isolation finger 56, the second gate 160, and the fixed third gate 172, respectively, whereby each time that the flip-flop switch moves from one position to another, either from closed to open, or from open to closed, the longitudinal positions relative to the conveyor belt of the finger 56 and the gates 160 and 172 will be altered.

Referring specifically to the isolation finger 56, which is moved transversely of the inlet guide channel by the cylinder-and-piston 58, said cylinder-and-piston is secured by means of struts 224 to the piston rod of a cylinder-and-piston 226 so oriented that when the piston is actuated it will move in a direction parallel to the direction of travel of the conveyor belt 30. The cylinder-and-piston 226 is mounted by means of a screw and wing nut (not shown) so as to be adjustable in a slot 228 in a fixed bracket 230. The slot extends in a direction parallel to the direction of movement of the conveyor belt. By adjusting the position of the cylinder-and-piston 226 in the slot 228, the longitudinal position of the isolation finger 56 with respect to the direction of travel of the conveyor belt can be set to obtain a desired number of segregated containers in the string between the finger 56 and gate 76 as mentioned heretofore in connection with massing an orthogonal pattern of containers in a tray. This, however, is not the staggering operation. The throw of the piston 226 is equal to the diameter of a single container. This throw can be adjusted by means (not shown) to accommodate containers of different diameters. Opposite ends of the cylinder are connected by conduits to a four-way valve 232 having ports connected to a source of air under pressure and the ambient atmosphere in the manner described with respect to the four-way valves discussed previously. Like these earlier four-way valves, the four-way valve 232 is moved to actuated position by a solenoid and to idle position by a return spring. When the valve 232 is in its actuated position with its piston rod extended, it locates the finger 56 in a downstream position so as to segregate in the string between this finger and the gate 76 the maximum of a selected number of containers forming a string that will completely fill a transport tray breadthwise. When the valve 232 is in its idle position, location of the finger 56 is shifted downstream of the aforesaid downstream position by the diameter of one container. Thus, when the switch 216 is in one position the finger 56 is in its upstream position, and when the switch 216 is in its other position the finger 56 is in its downstream position. Thereby the required selection between the number of containers in a string for effecting a staggered pattern of containers in the tray is achieved. The cam 210 actuates the switch 212 at position VIII in a string-transferring cycle, this being shortly after the gate 76 is extended and the finger 56 retracted, and after the last container in a string of containers released for movement down the conveyor past the first gate 76 has cleared this gate.

Similar cylinders-and-pistons 234, 236 with associated similar four-way valves 238, 240 are associated with the cylinder-and-piston 162 and the third gate 172 in order to shift the second and third gates, respectively, in a direction lengthwise of the conveyor and upstream when the finger 56 is shifted downstream to shorten the length of a segregated string upstream of the first gate 76. The shift of the second and third gates is, however, not equal to the full diameter of a container as in the case of the finger 56, but rather only one-half of such diameter. Due to this half diameter upstream shift, when either one of the gates 160, 172 so shifted is operable to block a string of containers moving with the conveyor belt, the halted string will be displaced one-half container upstream, and thus will properly locate the halted string for staggering with respect to the previously transferred string. The second or third gate operable for blocking for any tray-loading cycle moves upstream when it is arranged to block a shorter string of containers, and it is shifted downstream to its downstream position when it is arranged to block a longer string of containers, the longer string being one container longer than the shorter string. Thus when a pusher operates on a longer string, the containers in that string will be swept into the mouth of the tray with the leading and trailing containers of the string adjacent the side walls of the tray, but in the next transferring cycle the pusher wall 140 will sweep a one-shorter string of containers into the tray with the leading container one-half a container diameter upstream with respect to the leading container of the preceding string and with the trailing container of the shorter string one-half diameter downstream of the position of the trailing container of the previously transferred string. In this manner, the desired staggered relationship illustrated in FIG. 10 of successive strings of containers will be achieved.

It is to be observed that the second and third gates 160 and 172 have downstream faces which are perpendicular to the direction of travel of containers moving with the conveyor belt and that these faces extend substantially all the way to the inner faces of the downstream side walls 114 of the transport trays positioned on the top platen 38. When said gates either are in position for orthogonal stacking or in position to block the longer string of containers in staggered stacking, the leading container of a string and, hence, the balance of the string, are maintained in properly longitudinal relationship to the breadth of the tray as the transfer of the containers from the conveyor belt to the tray is effected. The downstream edges of the pusher walls and retainer walls are spaced slightly upstream from the associated gates when they are in downstream container-blocking position in order to allow the one-half container diameter upstream shifting of these gates when the loader is operating in a staggered mode, and when the pusher walls are in engagement with a shorter string of containers.

It also may be mentioned that it is most desirable to include means to prevent the trays from being displaced forwardly when the pushers are actuated, such displacement being particularly prone to occur when there are many containers in a tray so that a substantial frictional coupling exists between the containers and the tray. Such means includes a stop 242 which is biased toward the tray by a tension spring 244 anchored at one end to a stop mounting rod 246 and at the other to a bracket 248. The bracket can be adjusted in a direction parallel to the direction of pusher movement by varying the position of a bracket carrying shaft 250 mounted for adjustment parallel to the rod 246. Said means also is useful for another purpose; if the counter 160 errs and permits one too many strings to be transferred to a tray, the stop 242 will yield, after which the switch 192 will open and stop the loader.

As a matter of good machine design, it is desirable to off-load containers from the conveyor belt by the pushers at a rate slightly in excess of the rate at which the containers are fed onto the conveyor belt at the inlet end 22. This necessarily results in a depletion of the number of containers accumulated upstream of the first gate. As a consequence, at certain intervals there will not be enough containers for form a complete string. According to an ancillary feature of the invention, means is included automatically to stop the loading cycle when the number of containers downstream of the isolation finger is too few and to automatically restart the loading cycle when the number of containers downstream has sufficiently increased. The means to automatically stop the loading cycle constitutes the switch 50, the timer 178, the end-of-cycle switch 182, the cam 184 and the relay 188. The means to automatically restart the loading cycle constitutes a second sensor 252 upstream of the first sensor 46. The second sensor emits a pulse each time that a container passes the same on the continually moving conveyor belt. The pulse travels over a wire 254 to a timer 256 which times the width of pulse so that when a container is stationary at the upstream sensor 252 this is recognized by the timer which emits a signal to the lead and from it to the switch 182. The switch, when closed at the end of a cycle, passes the signal over a lead 260 to the relay 188 to close the same.

It is also possible to create a staggered pattern of containers in the tray by using the stagger switch but not changing the length of string each cycle. The string length is set by locating the isolation finger a distance from the first gate a distance one container diameter less than the full width of a tray. Then changing the position of the second and third gates on alternate cycles by a distance of a continuous radius will result in a beehive pattern.

It thus will be seen that there are provided devices which achieve the several objects of the invention and are well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein described and shown in the accompnying drawings is to be interpreted as illustrative and not in a limiting sense.

Claims

Having thus described our invention, we claim as new and desire to secure by Letters Patent:

1. A tray loader comprising:

a. an inlet for receiving erect containers,

b. a tray loading station,

c. means associated with said station for horizontally supporting a tray having an open mouth,

d. a flat top conveyor belt,

e. means supporting said conveyor belt for travel of an upper reach thereof in front of the open mouth of a tray at said loading station from said inlet through a position upstream of the loading station to a position downstream of the loading station,

f. means continually moving said conveyor belt so that said upper reach continually moves from said inlet to said downstream position,

g. means at the downstream side of the loading station blocking movement of containers with the conveyor belt,

h. a linear pusher having a retracted position and an extended position, said pusher in extended position being on the side of the conveyor belt adjacent the mouth of the tray, and in retracted position being on the side of the conveyor belt remote from the mouth of the tray,

i. means moving said pusher from its retracted to its extended position to sweep into the open mouth of the tray a linear row of containers held stationary on the moving conveyor belt by said blocking means and then back to its retracted position, said row tending to lose its linearity due to lengthwise pressure exerted on the stationary containers by the conveyor belt moving beneath the same, and

j. means maintaining the linearity of said row of containers while it is in a stationary position on the moving conveyor belt in front of the open mouth of the tray and as it is swept off the conveyor belt into the open mouth of the tray, said last named means comprising a linear retainer parallel to said pusher, means to reciprocate said retainer horizontally and to reciprocate said retainer vertically, said retainer moving means moving said retainer from a starting position synchronously with said pusher as the pusher sweeps a string of containers off the conveyor belt into the mouth of the tray, moving said retainer upwardly after the string of containers is swept off the conveyor belt and thereafter moving the retainer back to its starting position.

2. A tray loader as set forth in claim 1, wherein the means reciprocating the retainer vertically moves the retainer upwardly before the means moving the pusher horizontally completes its movement of a string of containers into the tray.

3. A tray loader as set forth in claim 1, wherein the means reciprocating the retainer vertically moves the retainer downwardly after the means moving the retainer horizontally moves the retainer on its way back to starting position a distance beyond a string of containers freshly moved into the tray by the pusher.

4. A tray loader comprising:

a. an inlet for receiving erect transversely round containers,

b. first and second tray loading stations,

c. means associated with said stations for horizontally supporting at each a tray having an open mouth with the mouths facing in the same direction and in transverse alignment,

d. a flat topped conveyor,

e. means supporting said conveyor for travel successively in front of the open mouths of trays at said loading stations from the inlet through a position upstream of the upstream loading station to a position downstream of the downstream loading station,

f. means for moving said conveyor so that it moves from said inlet to said downstream position,

g. first and second pusher means each associated with a different one of said loading stations for transferring strings of containers from said conveyor off said conveyor into the trays at the first and second tray loading stations, said pusher means being selectively operable first to at least substantially fill a tray at one of said loading stations and then a tray at said other loading station,

h. said conveyor being a conveyor belt that moves continually,

i. first means downstream of the first loading station selectively blocking movement of containers with the conveyor belt and permitting movement of containers with the conveyor belt,

j. second means downstream of the second loading station blocking movement of containers with the conveyor belt so that when said first blocking means is in container blocking position, the first pusher means is effective, and when in container passing position the first pusher means is ineffective and the second blocking means and the second pusher means is effective, and

k. means maintaining the linearity of a string of containers blocked by either of said blocking means while the string is in stationary position on the moving conveyor belt in front of the open mouth of a tray and as the string is transferred off the conveyor belt into the open mouth of a tray at the loading station at which the string of containers leaves the conveyor belt.

5. A tray loader as set forth in claim 4, wherein the means for maintaining the linearity of a string of containers comprises a different linear retainer parallel to each associated pusher means, means to reciprocate each retainer horizontally and to reciprocate each retainer vertically, said retainer moving means moving each retainer from a starting position synchronously with the associated pusher means as that pusher means transfers a string of containers off the container belt into the mouth of a tray at a loading station, moving said retainer upwardly after the string of containers is transferred off the conveyor belt and thereafter moving the retainer back to its starting position.

6. A tray loader comprising:

a. an inlet for receiving erect containers,

b. first and second tray loading stations,

c. means associated with said stations for horizontally supporting at each a tray having an open mouth with the mouths facing in the same direction and in transverse alignment,

d. a flat topped conveyor,

e. means supporting said conveyor for continual travel successively in front of the open mouths of trays at said loading stations from the inlet through a position upstream of the upstream loading station to a position downstream of the downstream loading station,

f. means for moving said conveyor so that it moves from said inlet to said downstream position,

g. first and second pusher means each associated with a different one of said loading stations for transferring strings of containers from said conveyor off said conveyor into the trays at the first and second tray loading stations, said pusher means being selectively operable first to at least substantially fill a tray at one of said loading stations and then a tray at said other loading station; and

h. means upstream of the first loading station to segregate a linear string of a predetermined number of containers equal in total width to the width of a tray in stationary position with the conveyor belt moving therebeneath and from time to time to release the string for movement downstream to one or the other of the loading stations to be transferred off the same into an associated tray.

7. A tray loader as set forth in claim 6 wherein the segregating means includes a gate movable between a position blocking containers on the belt and a position permitting the passage of containers on the belt and an isolation finger upstream from the gate and movable between a position permitting passage of containers on the belt and a position blocking movement of containers with the belt, the space parallel to the belt between the gate and the finger determining the number of containers in the string.

8. A tray loader as set forth in claim 6, wherein, after the last one of the string of containers has cleared the segregating means, the segregating means starts to gather a new string of containers.

9. A tray loader comprising:

a. an inlet for receiving erect containers,

b. a tray loading station,

c. means associated with said station for horizontally supporting a tray having an open mouth,

d. a flat top conveyor belt,

e. means supporting said belt for travel of an upper reach thereof in front of the open mouth of a tray at said loading station from the inlet through a position upstream of the loading station to a position downstream of the loading station,

f. means continually moving said conveyor belt so that said upper reach continually moves from said inlet to said downstream position,

g. first means upstream of the loading station selectively blocking movement of containers with the conveyor belt and permitting movement of containers with the conveyor belt,

h. an isolation finger upstream of the first blocking means selectively blocking movement of the containers with the conveyor belt and permitting movement of the containers with the conveyor belt,

i. second means at the downstream side of the loading station blocking movement of containers with the conveyor belt,

j. said first blocking means in blocking position holding stationary a linear row of containers behind it while the isolation finger is in position permitting movement of containers with the conveyor belt until more than a predetermined number of containers is blocked behind the first blocking means,

k. means thereafter shifting said isolation finger to a position blocking movement of containers upstream thereof with the conveyor belt so that a string of a predetermined number of containers is segregated in stationary condition and linear arrangement on the conveyor belt between the isolation finger and the first blocking means,

l. means for subsequently shifting said first blocking means to a position to permit movement of said string of containers as a unit with the conveyor belt to a position in front of the open mouth of the tray at the loading station to be held stationary by the second blocking means,

m. means for subsequently shifting the isolation finger to container passing position, and

n. a pusher having a retracted position and an extended position, said pusher in retracted position being on the side of the conveyor belt remote from the mouth of a tray and in extended position being on the side of the conveyor belt adjacent the mouth of a tray, said pusher as it moves from retracted to extended position transferring the string of containers held stationary by the second blocking means from the moving conveyor belt into said tray through the open mouth thereof.

10. A tray loader as set forth in claim 9, wherein after the last container in the linear string of containers clears the first blocking means, said blocking means is arranged to move back to container-blocking position to commence the grouping of a fresh linear string of containers.

11. A tray loader comprising:

a. an inlet for receiving erect containers,

b. a tray loading station,

c. means associated with said station for horizontally supporting a tray having an open mouth,

d. a flat top conveyor belt,

e. means supporting said belt for travel of an upper reach thereof in front of the open mouth of a tray at said loading station from the inlet through a position upstream of the loading station to a position downstream of the loading station,

f. means continually moving said conveyor belt so that said upper reach continually moves from said inlet to said downstream position,

g. first means upstream of the loading station selectively blocking movement of containers with the conveyor belt and permitting movement of containers with the conveyor belt,

h. an isolation finger upstream of the first blocking means selectively blocking movement of the containers with the conveyor belt and permitting movement of the containers with the conveyor belt,

i. second means at the downstream side of the loading station blocking movement of containers with the conveyor belt,

j. said first blocking means in blocking position holding stationary a linear row of containers behind it while the isolation finger is in position permitting movement of containers with the conveyor belt until at least a predetermined number of containers is blocked behind the first blocking means,

k. means thereafter shifting said isolation finger to a position blocking movement of containers upstream thereof with the conveyor belt so that a string of a predetermined number of containers is segregated in stationary condition and linear arrangement on the conveyor belt between the isolation finger and the first blocking means,

l. means for subsequently shifting said first blocking means to a position to permit movement of said string of containers as a unit with the conveyor belt to a position in front of the open mouth of the tray at the loading station to be held stationary by the second blocking means,

m. means for subsequently shifting the isolation finger to container passing position,

n. a pusher having a retracted position and an extended position, said pusher in retracted position being on the side of the conveyor belt remote from the mouth of a tray and in extended position being on the side of the conveyor belt adjacent the mouth of a tray, said pusher as it moves from retracted to extended position transferring the string of containers held stationary by the second blocking means from the moving conveyor belt into said tray through the open mouth thereof; and means operable upon each reciprocation of the pusher to vary the position of the second blocking means in a direction longitudinally of the movement of the conveyor belt by a distance equal to one-half the diameter of a container so that strings of containers transferred into the tray will assume a staggered pattern.

12. A tray loader comprising:

a. an inlet for receiving erect containers,

b. a tray loading station,

c. means associated with said station for horizontally supporting a tray having an open mouth,

d. a flat top conveyor belt,

e. means supporting said belt for travel of an upper reach thereof in front of the open mouth of a tray at said loading station from the inlet through a position upstream of the loading station to a position downstream of the loading station,

f. means continually moving said conveyor belt so that said upper reach continually moves from said inlet to said downstream position,

g. first means upstream of the loading station selectively blocking movement of containers with the conveyor belt and permitting movement of containers with the conveyor belt,

h. an isolation finger upstream of the first blocking means selectively blocking movement of the containers with the conveyor belt and permitting movement of the containers with the conveyor belt,

i. second means at the downstream side of the loading station blocking movement of containers with the conveyor belt,

j. said first blocking means in blocking position holding stationary a linear row of containers behind it while the isolation finger is in position permitting movement of containers with the conveyor belt until at least a predetermined number of containers is blocked behind the first blocking means,

k. means thereafter shifting said isolation finger to a position blocking movement of containers upstream thereof with the conveyor belt so that a string of a predetermined number of containers is segregated in stationary condition and linear arrangement on the conveyor belt between the isolation finger and the first blocking means,

l. means for subsequently shifting said first blocking means to a position to permit movement of said string of containers as a unit with the conveyor belt to a position in front of the open mouth of the tray at the loading station to be held stationary by the second blocking means,

m. means for subsequently shifting the isolation finger to container passing position,

n. a pusher having a retracted position and an extended position, said pusher in retracted position being on the side of the conveyor belt remote from the mouth of a tray and in extended position being on the side of the conveyor belt adjacent the mouth of a tray, said pusher as it moves from retracted to extended position transferring the string of containers held stationary by the second blocking means from the moving conveyor belt into said tray through the open mouth thereof; and

o. means operable upon each reciprocation of the pusher to vary the distance between the isolation finger and the first blocking means by a distance equal to a diameter of one container.

13. A tray loader as set forth in claim 11, wherein means is included operable upon each reciprocation of the pusher to vary the distance between the isolation finger and the first blocking means by a distance equal to a diameter of one container.

14. A tray loader comprising:

a. an inlet for receiving erect containers,

b. a tray loading station,

c. means associated with said station for horizontally supporting a tray having an open mouth,

d. a flat top conveyor belt,

e. means supporting said belt for travel of an upper reach thereof in front of the open mouth of a tray at said loading station from the inlet through a position upstream of the loading station to a position downstream of the loading station,

f. means continually moving said conveyor belt so that said upper reach continually moves from said inlet to said downstream position,

g. first means upstream of the loading station selectively blocking movement of containers with the conveyor belt and permitting movement of containers with the conveyor belt,

h. an isolation finger upstream of the first blocking means selectively blocking movement of the containers with the conveyor belt and permitting movement of the containers with the conveyor belt,

i. second means at the downstream side of the loading station blocking movement of containers with the conveyor belt,

j. said first blocking means in blocking position holding stationary a linear row of containers behind it while the isolation finger is in position permitting movement of containers with the conveyor belt until at least a predetermined number of containers is blocked behind the first blocking means,

k. means thereafter shifting said isolation finger to a position blocking movement of containers upstream thereof with the conveyor belt so that a string of a predetermined number of containers is segregated in stationary condition and linear arrangement on the conveyor belt between the isolation finger and the first blocking means,

l. means for subsequently shifting said first blocking means to a position to permit movement of said string of containers as a unit with the conveyor belt to a position in front of the open mouth of the tray at the loading station to be held stationary by the second blocking means,

m. means for subsequently shifting the isolation finger to container passing position,

n. a pusher having a retracted position and an extended position, said pusher in retracted position being on the side of the conveyor belt remote from the mouth of a tray and in extended position being on the side of the conveyor belt adjacent the mouth of a tray, said pusher as it moves from retracted to extended position transferring the string of containers held stationary by the second blocking means from the moving conveyor belt into said tray through the open mouth thereof,

o. the second blocking means being selectively shiftable to a container-passing position,

p. a second tray loading station downstream of the first tray loading station,

q. means associated with said second station for horizontally supporting another tray having an open mouth,

r. a third means at the downstream side of the second loading station blocking movement of the containers with the conveyor belt, said third blocking means halting movement of the containers with the conveyor belt when the second blocking means permits movement of the containers with the conveyor belt whereby said third blocking means will halt a linear string of containers at the second tray loading station, and

s. a second pusher, said second pusher being located at the second loading station and having a retracted position and an extended position, said pusher in retracted position being on the side of the conveyor belt remote from the mouth of the other tray and in extended position being on the side of the conveyor belt adjacent the mouth of the other tray, said second pusher as it moves from retracted to extended position transferring the string of containers held stationary by the third blocking means from the moving conveyor belt into said other tray through the open mouth thereof.

15. A tray loader comprising:

a. an inlet for receiving erect containers,

b. a tray loading station,

c. means associated with said station for horizontally supporting a tray having an open mouth,

d. a flat top conveyor belt,

e. means supporting said belt for travel of an upper reach thereof in front of the open mouth of a tray at said loading station from the inlet through a position upstream of the loading station to a position downstream of the loading station,

f. means continually moving said conveyor belt so that said upper reach continually moves from said inlet to said downstream position,

g. first means upstream of the loading station selectively blocking movement of containers with the conveyor belt and permitting movement of containers with the conveyor belt,

h. an isolation finger upstream of the first blocking means selectively blocking movement of the containers with the conveyor belt and permitting movement of the containers with the conveyor belt,

i. second means at the downstream side of the loading station blocking movement of containers with the conveyor belt,

j. said first blocking means in blocking position holding stationary a linear row of containers behind it while the isolation finger is in position permitting movement of containers with the conveyor belt until at least a predetermined number of containers is blocked behind the first blocking means,

k. means thereafter shifting said isolation finger to a position blocking movement of containers upstream thereof with the conveyor belt so that a string of a predetermined number of containers is segregated in stationary condition and linear arrangement on the conveyor belt between the isolation finger and the first blocking means,

l. means for subsequently shifting said first blocking means to a position to permit movement of said string of containers as a unit with the conveyor belt to a position in front of the open mouth of the tray at the loading station to be held stationary by the second blocking means,

m. means for subsequently shifting the isolation finger to container passing position,

n. a pusher having a retracted position and an extended position, said pusher in retracted position being on the side of the conveyor belt remote from the mouth of a tray and in extended position being on the side of the conveyor belt adjacent the mouth of a tray, said pusher as it moves from retracted to extended position transferring the string of containers held stationary by the second blocking means from the moving conveyor belt into said tray through the open mouth thereof,

o. a sensor upstream of the isolation finger to detect the absence of a container thereat, and

p. means to stop operation of the pusher when no containers are at the sensor.

16. A tray loader as set forth in claim 15, wherein a second sensor is provided upstream of the first sensor, said second sensor detecting the presence of a stationary container thereat and wherein means is included to start operation of the machine upon detection of a stationary container at the second sensor.

17. A tray loader comprising:

a. a loading station,

b. a tray at said station, said tray having an open mouth and a receiving area configured to hold a predetermined number of containers of a specific cross section,

c. means for presenting containers in front of the open mouth of the tray,

d. means for pushing containers from the presenting means into the tray through the open mouth thereof,

e. means for sensing an effort to push into the tray containers in excess of said predetermined number, and

f. means responsive to said sensing means for rendering the pushing means ineffective,

g. the tray being movable in a direction away from the pushing means,

h. the sensing means being responsive to movement of the tray away from the pushing means.

18. A tray loader as set forth in claim 17, wherein means is included to resiliently urge the tray toward the pushing means.

19. A tray loader comprising:

a. an inlet for receiving erect transversely round containers,

b. a tray loading station,

c. means associated with said station for horizontally supporting a tray having an open mouth,

d. a flat top conveyor belt,

e. means supporting said conveyor belt for travel of an upper reach thereof in front of the open mouth of a tray at said loading station from said inlet through a position upstream of the loading station to a position downstream of the loading station,

f. means continually moving said conveyor belt so that said upper reach continually moves from said inlet to said downstream position,

g. means at the downstream side of the loading station blocking movement of containers with the conveyor belt,

h. a linear pusher having a retracted position and an extended position, said pusher in extended position being on the side of the conveyor belt adjacent the mouth of the tray, and in retracted position being on the side of the conveyor belt remote from the mouth of the tray,

i. means moving said pusher from its retracted to its extended position to sweep into the open mouth of the tray a linear row of containers held stationary on the moving conveyor belt by said blocking means and then back to its retracted position, said row tending to lose its linearity due to lengthwise pressure exerted on the stationary containers by the conveyor belt moving beneath the same, and

j. means maintaining the linearity of said row of containers while it is in a stationary position on the moving conveyor belt in front of the open mouth of the tray and as it is swept off the conveyor belt into the open mouth of the tray.