Apparatus for controlling conveyance of articles

Abstract

A conveyor system comprises a first conveyor for conveying articles and a second conveyor disposed at one end of the first conveyor transversely thereof for receiving the articles therefrom. The second conveyor, adapted to accumulate the articles, includes a plurality of support rollers arranged in two rows longitudinally thereof, a drive chain interposed between the two rows of rollers, pushers tiltably mounted each at the approximate midportion of its length on the drive chain at specified spacing and each having an upper end projecting upward from the chain to engage the article and a lower end carrying a roller and projecting downward from the chain, and levers tiltably mounted each at the approximate midportion of its length on the drive chain and positioned in front of the pushers in mating combination therewith, each of the levers being adapted to be pushed down by contact with a stopped article while travelling with the drive chain and to thereby tilt the mating pusher. Disposed forwardly of the first conveyor in opposing relation to the front end thereof and under the drive chain of the second conveyor is a cam upwardly movable to come into contact with the roller at the lower end of the pusher to position the pusher upper end below the upper end of the support roller and downwardly movable out of contact with the lower end of the pusher. At the end of the first conveyor, there are provided pushing members pivotally reciprocally movable between an upper position and a lower position with respect to the upper ends of article supporting rollers included in the first conveyor. When moving from the lower position to the upper position, the pushing members come into contact with the rear end of the article to push the article toward the second conveyor and to thereby discharge the article completely from the first conveyor at the upper position. Further disposed forwardly of the first conveyor are receiving members pivotally reciprocally movable between an upper position and a lower position with respect to the upper ends of article supporting rollers of the second conveyor. At the upper position, the receiving members receive the article sent out from the first conveyor and, in the course of the forward movement from the upper position, the receiving member place the article onto the support rollers of the second conveyor.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for controlling article conveying operation, more particularly to an apparatus to be incorporated in a conveyor system having a first conveyor for conveying articles and a second conveyor disposed at one end of the first conveyor transversely thereof to receive the articles from the first conveyor, the apparatus being operable to control the article conveying operation of the first and second conveyors.

Throughtout the specification and the appended claims, the terms "front" or "forward" and "rear" or "rearward" are used with respect to the direction of travel of the conveyor. Thus "forward" refers to the direction of advance of the conveyor, while by "rearward" is meant the direction opposite thereto.

In the case where articles are transported on conveyors, there arises a need to stop the articles in the course of conveying operation at an intermediate position of the path of travel of the articles for working, inspection, testing or like purposes. On such occasion, it is more convenient to accumulate a number of articles in the form of a row of closely arranged articles than to leave them separated from each other. To assure such convenience, conveyors have already been provided and put to use which comprise a drive chain having a number of pushers mounted thereon at specified spacing and engageable with and disengageable from the articles to be conveyed and rotatable support members adapted to merely support the articles so as to accumulate the articles.

If the aforementioned second conveyor is used as a main conveyor for conveying articles all the time, with the first conveyor serving as a branch conveyor for transferring the articles onto the second conveyor or main conveyor only when so required, it will be more advantageous to employ a conveyor of the accumulation type for the second conveyor at least for the foregoing reason. However, the conveying system will then involve the following problem. Since the accumulation-type conveyor has the construction described, the pushers on the drive chain invariably project upward from the rotatable support members and therefore impede the transfer of the articles from the first conveyor onto the second conveyor. Furthermore, inasmuch as the direction of advance of the first conveyor and that of the second conveyor intersect each other at right angles, it is difficult to transfer the articles smoothly.

These difficulties heretofore experienced have made it impossible to employ the accumulation-type conveyor for the second or main conveyor.

SUMMARY OF THE INVENTION of comprising drive

The object of this invention is to provide an apparatus for controlling conveyance of articles employable in a conveyor system including a first conveyor and a second conveyor connected thereto in a T-shaped arrangement and serving as the main conveyor so as to permit the use of a conveyor of the accumulation type as the second conveyor. The second conveyor according to this invention comprises a number of article supporting rotatable members arranged in two rows longitudinally thereof; a drive chain interposed between the two rows of supporting members in parallel thereto and positioned below the supporting members; a number of normally raised pushers tiltably pivoted, each at an intermediate portion of its length, to the drive chain at specified spacing and each having an upper projection and a lower projection, the upper projection being engageable with an article on the supporting members when in raised position and disengageable from the article when tilted; and means for tilting the pusher in engagement with an advancing article when the article approaches a preceding article stopped during transport, whereby when the desired one of a great number of articles is stopped the following articles can be brought to a halt one after another in accumulated fashion.

Disposed forwardly of the first conveyor in opposing relation to the front end thereof and positioned under the drive chain of the second conveyor is an upwardly and downwardly movable cam having a horizontal upper surface of a length approximately equal to the width of the first conveyor and downwardly slanting surfaces at its front and rear ends. The lower projection of the pusher projecting downward from the chain is pushed upward by the horizontal surface when the cam ascends to bring the upper projection of thereof down to a level lower than the supporting members. When descending, the horizontal surface moves out of contact with the lower projection of the pusher. When the article is to be transferred from the first conveyor to the second conveyor, the article advancing on the first conveyor is brought to a halt just before the junction between the two conveyors. Simultaneously with this, the pusher on the drive chain of the second conveyor which pusher is positioned in front of the front end of the first conveyor over the distance corresponding to the width of the first conveyor is lowered by the cam to a level below the upper ends of the rotatable supporting members so that the pushers will not interfere with the article to be transferred onto the second conveyor. The apparatus further includes means for transferring articles from the first conveyor onto the second conveyor, whereby the articles can be transferred from the former to the latter free of trouble, although the direction of travel of the former intersects that of the latter at right angles.

This invention will be described below in greater detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing an embodiment of the apparatus for controlling article conveying operation of this invention wherein the T-shaped junction of a first conveyor and a second conveyor is illustrated;

FIG. 2 is a view in section taken along the line II--II in FIG. 1, part of the first conveyor being broken away;

FIG. 3 is a side elevation showing the second conveyor in FIG. 1 partly broken away to illustrate article receiving and transferring means;

FIG. 4 is a bottom view of a pallet which is the article to be conveyed;

FIG. 5 is a side elevation of the pallet;

FIG. 6 is a front view of the pallet;

FIG. 7 is a plan view on an enlarged scale showing part of a drive chain having a pusher and a pusher tilting lever in combination therewith;

FIG. 8 is a view in section taken along the line VII--VII in FIG. 7;

FIG. 9 is a side elevation of the drive chain of FIG. 7, the view particularly showing an article in engagement with the pusher and advancing with the drive chain as it is approaching a preceding stopped article, the articles being shown partly in section;

FIG. 10 is a side elevation corresponding to FIG. 9 and showing the drive chain in FIG. 9 in further advanced position and front and rear articles in accumulated state;

FIG. 11 is a side elevation corresponding to FIG. 7 and showing the article while advancing in engagement with the pusher in the absence of a stopped article and when a cam is in its lowered position; and

FIG. 12 is a side elevation corresponding to FIG. 11 and showing the cam in its elevated position and the pusher and the lever for operating the pusher as positioned below the upper ends of the supporting rollers.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1 to 3, there is shown a conveyor system including a first conveyor 1 for conveying articles and a second conveyor 2 disposed at one end of the first conveyor 1 transversely thereof for receiving the articles from the first conveyor 1. The second conveyor 2 serves as the main conveyor. The second conveyor 2 includes posts 3 spaced apart by a specified distance transversely thereof in pairs and disposed at predetermined spacing longitudinally of the conveyor 2. A beam 4 extends between and secured to the transverse pair of posts 3 at the approximate middle of height of the posts. Mounting plates 5 are fixed to one side surface of each beam 4 toward the opposite ends of the beam respectively. Longitudinal bars 6 at right angles to the beams 4 and extending in parallel to each other lengthwise of the second conveyor 2 are fixed to the upper ends of the mounting plates 5. A number of support rollers 7 are mounted on each of the longitudinal bars 6 at specified spacing longitudinally thereof. Toward the midportion of each beam 4, a pair of vertical angle bars 8 are secured to the beam as if in suspension. Secured to the upper ends of the angle bars 8 are upper rails 9 extending longitudinally of the second conveyor 2 at right angles to the beams 4 and having a U-shaped cross section, with their opening sides opposing each other. Like the upper rails 9, lower rails 10 L-shaped in cross section are secured to the angle bars 8 at their lower ends. At the center of the second conveyor 2, an endless chain 11 extends between and in parallel to the two rows of support rollers 7, the chain 11 being positioned at a lower level than the rollers 7. The endless chain 11 is provided on its opposite sides with rollers 12 rollable along the rails 9 and 10, the rollers 12 being mounted on each connecting portion of the links constituting the chain 11. The chain 11 is driven by an unillustrated electric motor and known transmission means, with the upper side of the chain travelling in the direction of the arrow in FIG. 1 all the time. Guide rails 13, C-shaped in cross section, are secured to the two rows of posts 3 arranged longitudinally of the conveyor 2 at the inner sides of upper ends of the posts. The opening sides of the rails 13 are directed outwardly of the conveyor 2.

FIGS. 7 to 10 show the details of the drive chain 11, especially the pushers and levers for tilting the pushers. The chain 11 comprises pairs of inner links 14 and pairs of outer links 15 arranged alternately and connected together by pins 16 each carrying the rollers 12 at its opposite ends respectively. Inner links 17 spaced by a distance greater than the length of articles P are formed at their opposite ends with upstanding portions 18 and 19 unlike the other inner links 14. Each pusher 21 is tiltably mounted, at an intermediate portion of its length, on the rear upstanding portions 19 by means of a pivot 20. The pusher 21 is composed of two plates connected together and spaced by a predetermined distance and has an upper projection 21a projecting obliquely upward and engageable with the article P, a lower projection 21b of a greater width carrying a roller 22 on a pin 23 at its lower end and projecting downward from the chain 11, and a front projection 24 extending horizontally forward approximately from the position of the pivot 20. A tiltable lever 26 mating with the pusher 21 to tilt the same is mounted, at an intermediate portion of its length, on the front upstanding portions 18 by means of a pivot 25. The lever 26 is composed of two plates connected together and spaced by a smaller distance than the two plates of the pusher 21. The lever 26 has an upper projection 26a carrying a roller 27 on a pin 28 at its upper end, a rear projection 29 extending substantially toward the pusher 21 and overlapping the front projection 24 of the pusher 21, and a lower projection 26b having a lower end slight projecting from the lower end of the links of the chain 11 and having a large width. A vertical link 30 is interposed between the front projection 24 of the pusher 21 and the end of rear projection 29 of the lever 26. The link 30 is pivotally connected, at its upper end, to a pin 31 on the end of rear projection 29 and, at its lower end, to a pin 32 on the end of front projection 24. Both the pusher 21 and lever 26 are normally maintained in raised position under gravity acting on the portions thereof under the pivots 20 and 25 respectively, and the vertical front surface of the lower projection 21b and the vertical rear surface of the lower projection 26b abut against the pins 16 positioned immediately below the pivots 20 and 25 respectively, whereby they are made retainable in position. More specifically, the pins 16 serve as stoppers for preventing the upper projection 21a of the pusher 21 from turning rearward from the raised position and for preventing the upper projection 26a of the lever 26 from turning forward, respectively. The upper end of upper projection 21a of the pusher 21 is positioned above the roller 27 of the lever 26. The article P on the second conveyor 2 is supported on the rollers 7 and travels with the drive chain 11 by virtue of engagement with the pusher 21 on the chain 11, with its widthwise side surfaces moving along the guide rails 13.

The first conveyor 1 shown in FIGS. 1 and 3 is of the accumulation type substantially the same as the second conveyor 2. However, the front part of the frist conveyor extending from its front end some distance rearward includes a pair of endless chains 34 disposed in parallel side by side longitudinally of the conveyor and equipped with pushers 33 only, the chains 34 being adapted to send out the articles. Pushers 33 are mounted on the links of the chains 34 in upright position and carry rollers 42 at their upper ends. Provided in the rear of the chains 34 in overlapping relation thereto is a drive chain which is substantially equivalent to the drive chain 11 incorporated in the second conveyor 2 and equipped with pushers 21 and levers 26. By an electric motor and transmission means, both the chains are driven in synchronism, with the upper sides thereof travelling in the directions of arrows in FIGS. 1 and 2. Since the drive chain of the first conveyor 1 is not different from the drive chain 11 of the second conveyor 2 as described above, it is not shown in the drawings. Sprocket wheels 35 around which the chains 34 are reeved (rear sprocket wheels, not shown) are mounted on a shaft 38 supported by bearings 37 on outer frames 36. A pair of longitudinal bars 39 extending in parallel longitudinally of the first conveyor 1 are provided, on the inner surfaces thereof, with a number of rollers 40 arranged at specified spacing. The upper ends of rollers 40 of the first conveyor 1 are positioned at a slightly higher level than the rollers 7 of the second conveyor 2. Guide rails 41 disposed outside the longitudinal bars 39 are positioned above the guide rails 13 of the second conveyor 2 by the difference in level between the rollers 40 and the rollers 7. One of the two guide rails 13 in the second conveyor 2 which is positioned toward the first conveyor 1 is partially cut away at the junction of the first conveyor 1 and the second conveyor 2 to form an opening 43, the removed length of the rail corresponding to the space between the two guide rails 41 of the first conveyor 1.

With the first conveyor 1, each article P is supported on the rollers 40 and is advanced by virtue of engagement with the pusher on the drive chain while the lengthwise sides thereof are being guided by the rails 41. When approaching the front end of the first conveyor 1, the article is freed from engagement with the pusher but is subsequently engaged by the pushers 33 on the chains 34, whereby it is sent forward. If the chain corresponding to the drive chain 11 should extend to the front end of the first conveyor 1, the pusher which has been in engagement with the front end of the article P would be moved out of engagement with the article P when the drive chain travels around the periphery of the associated sprocket wheel as will be apparent from the drawing, allowing the article to remain on the support rollers 40 instead of being forwarded toward the second conveyor 2. Supposedly, the succeeding pusher would push the article P forward, but the pusher-tilting lever positioned in front of the particular pusher will then come into contact with the article P to move the pusher downward before the pusher engages the rear portion of the stopped article P as will be described later. Consequently, the succeeding pusher will pass away under the bottom of the article without engagement. For this reason, the article discharging chains 34 are used. The chains for sending out the articles may alternatively be of a known construction.

The first conveyor 1, which is employed as a branch conveyor, need not necessarily be of the accumulation type but may be a usual belt conveyor, chain conveyor, drive-type roller conveyor or the like. Apparently, the article discharging chains 34 can then be dispensed with.

In the present embodiment which is given for illustrative purposes only, the article P to be conveyed is exemplified as a pallet, which is specifically shown in FIGS. 4 to 6 and FIGS. 9 to 12. The pallet comprises a rectangular loading plate 44 as a main body. Projecting downward from the under surface of the loading plate 44 at the midportions of its four sides are lugs 45 and 46 with which the upper projection 21a of the pusher 20 on the drive chain 11 is engageable from inside. Rails 47 and 48 of inverted hatlike cross section for rolling contact with the roller 27 of the lever 26 extend between the pair of lugs 45 opposing each other lengthwise of the loading plate 44 and between the pair of lugs 46 opposing widthwise of the loading plate, respectively. These rails are secured to the under surface of the loading plate 44. The rails 47 and 48 have a width which is smaller than the space between the two plates constituting the pusher 21 and are formed, each at its opposite ends, with upwardly slanting portions 47a and 48a for permitting the roller 27 to come into or out of rolling contact with the rails smoothly. Of course, the lugs 45 and 46 have a greater width than the rails 47 and 48 so that the two plates of the pusher 20 can contact therewith. Further to enable the roller 27 to come into or out of rolling contact with the rails, the lower ends of the lugs 45 and 46 coincide with the outer ends of the slanting portions 47a and 48a. The loading plate 44 is fixedly provided on its under surface with pairs of parallel slider members 49 and 50 of inverted hatlike cross section for moving contact with the supporting rollers 7 and 40 included in the second and first conveyors 1 and 2 respectively. The lower ends of the slider members 49 and 50 and those of the rails 47 and 48 are all included in the same plane and, where any two of these members or rails intersect each other, one of them is partially cut away at the intersection to render them flush with each other. On the opposite sides of the lugs 46, lugs 51 project downward from the loading plate 44 with which pushers 33 on the two article discharging chains 34 come into contact from outside. Although not shown, the second conveyor 2 is likewise equipped at its front end with pusher-carrying chains substantially equivalent to the chains 34 in the first conveyor 1. Accordingly, downwardly projecting lugs 52 are similarly provided on the opposite sides of the lugs 45 so that the pushers will contact with the lugs 52 from outside. The lower ends of the lugs 51 and 52 are positioned in the same plane as the outer bottom surfaces of the rails 47 and 48 and those of the slider members 49 and 50. A pair of triangular reinforcing plates 53 bear against each of the lugs 51 and 52 and are fixed to the under surface of the loading plate 44. The lugs 45, 46, 51 and 52 are symmetrically disposed in pairs so as to render the pallet usable reversibly with respect to the opposite sides. Workpieces or the like to be conveyed are placed on such pallet and are sent forward on the conveyors 1 and 2.

FIGS. 9 and 10 illustrate the operation to accumulate articles which are being conveyed continuously on the conveyor at predetermined specing. At a specified portion of the second conveyor 2, an unillustrated stopper is disposed which is movable into or retractable from the path of movement of the upper end of the lever 26. When the articles are to be accumulated, the stopper is advanced into the path of movement. As will be stated later, the stopper may be a cam or like member which is movable into or removable from the path of travel of the roller 22 on the pusher 21. The stopper thus positioned pushes down the lever 26 in front of the pusher 21 in engagement with the front lug 45 of a first advancing article P.sub.1, causing its rear projection 29 to descend. Consequently, the link 30 acts to depress the front projection 24 of the pusher 21. This movement tilts the pusher 21, disengaging the upper projection 21a thereof from the lug 45 of the article P.sub.1, whereby the first article P.sub.1 is brought to a halt. By the "first article" herein referred to is meant one of a number of travelling articles which is to be stopped first. When the first article P.sub.1 is thus stopped, a second article P.sub.2 and the succeeding articles are still travelling with the drive chain 11 (see FIG. 9). The lever 26 for the pusher 21 engaging the article P.sub.2 then comes into contact with the preceding first article P.sub.1, which in turn acts on the lever 26 like the aforementioned stopper. The resulting inclination of the lever 26 pushes down the pusher 21 out of engagement with the second article P.sub.2, which therefore comes to a halt adjacent the first article P.sub.1 in accumulated state. The roller 27 on the lever 26 advances in rolling contact with the under surface of rail 47 on the first article P.sub.1. The upper projection 21a of the pusher 21, located at a lower level than the roller 27 when in tilted position, will not come into contact with the first article P.sub.1 (see FIG. 10). Inasmuch as the stopper is disposed in front of the front end of the first article P.sub.1, the lever 26 which has moved past the front end remains inclined until it passes by the stopper, retaining the pusher 21 also in its tilted position. Accordingly the pusher 21 will not rises to engage the lug 45 of the article P.sub.1 as shown in FIG. 9 upon the lever 26 moving past the front end of the article P.sub.1. As the drive chain 11 travels forward, a third article and the following articles are brought into halt one after another, each in end-to-end contact with the preceding article in accumulated fashion.

To move a group of stopped articles P again, the stopper is retracted from the path of movement of the lever 26. This permits the lever 26 advancing from behind to rise under gravity, the moment when it passes by the lug 45 of the first article P.sub.1 since it is freed from the pressure of the article P.sub.1 at that moment. Consequently, the pusher 21 is raised under gravity and by the upward movement of rear projection 29 of the lever 26 which is transmitted through the link 30 to the front projection 24 of the pusher 21. Thus the upper projection 21a of the pusher 21 engages the lug 45 of the article P.sub.1 to advance the article P.sub.1. It will be apparent that as the first article P.sub.1 moves forward which has been serving as a stopper, the succeeding pushers 21 come into engagement with the second and following articles P.sub.2 one after another, respectively, to thereby bring the articles P.sub.1 into travel.

The articles P are carried on the second conveyor 2 serving as a main conveyor, each with its length positioned longitudinally of the conveyor 2. To transfer the articles P sent forward by the first conveyor 1 which is a branch conveyor onto the second conveyor 2 without changing the orientation of the articles P, the articles P are conveyed on the first conveyor 1, each with its width positioned longitudinally of the conveyor. The articles P thus positioned on the first conveyor 1 are transferred onto the second conveyor 2 by pushing means 54 and receiving and transferring means 55 shown in FIGS. 1 to 3. The pushing means 54 comprises inner frames 56 disposed in the front portion of the first conveyor 1, a rod 58 supported by bearings 57 on the frames 56 and extending transversely of the frames 56, pivotal bars 60 fixed to the opposite ends of the rod 58 respectively and each extending upward to carry a roller 59 at its upper end, an ear 61 extending downward from the midportion of the rod 58, and a hydraulic cylinder 65 having a piston rod 62 whose end is pivoted to the ear 61 and a base end 63 whose ear is pivoted to an ear attached to a support 64 for frames 56. The receiving and transferring means 55 comprises base frames 66 included in the second conveyor 2 and disposed forwardly of the first conveyor 1, two rods 68 spaced apart from each other by a specified distance and extending transversely of the base frames 66, the rods 68 being supported by bearings 67 on base frames 66, pivotal bars 70 fixed to each of the rods 68 proximate to its opposite ends and each extending upward to carry a roller 69 at the upper end thereof, substantially L-shaped downwardly extending levers 71 each fixed to one end of each rod 68 which end extends outward from the bearing 67, a pair of links 72 connecting the two levers 71, and a hydraulic cylinder 75 having a piston rod 73 whose distal end is pivoted to lengthwise midportion of one of the levers 71 and a base end 74 whose ear is pivoted to a support member on the base frame 66.

When articles P are transferred from the first conveyor 1 onto the second conveyor 2, the pushers 21 and levers 26 on the second conveyor 2 positioned at a higher level than the rollers 7 would impede the advance of the articles. FIGS. 1 and 3 show cam means 76 for bringing the pushers 21 and levers 26 down to a level lower than the upper ends of the rollers 7. The cam means 76 comprises a barlike cam 77 disposed forwardly of the first conveyor 1 in opposing relation to the front end thereof and positioned under the drive chain 11 of the second conveyor 2 and pairs of elongated parallel links 78 having upper ends pivotally supporting the cam 77 and lower ends secured to the same rods 68 as the pivotal bars 70. The cam 77 has a horizontal upper surface 77a longer than the width of the first conveyor 1 and downwardly slanting surfaces 77b at its opposite ends. Each pair of the parallel links 78 are positioned on the opposite sides of the cam 77 to support the cam 77 at a position close to each end of the cam.

When the piston rod 62 is extended by the operation of the hydraulic cylinder 65, the pivotal bars 60 of the pushing means 54 are inclined rearward, bringing the rollers 59 at their upper ends to a level lower than the upper ends of the supporting rollers 40 as shown in the solid line in FIG. 2. When retracted, the piston rod 62 turns the pivotal bars 60 to upright position, bringing the rollers 59 to horizontal position above the upper ends of the supporting rollers 40 as indicated in the dot-and-dash line in FIG. 2. The article P carried on the first conveyor 1 is sent toward the second conveyor 2 by the discharging chains 34, more specifically by the rollers 42 on the upper ends of the pushers 33 mounted on the chains 34. At this time the longitudinal center line of the article P must be brought into alignment with the center line of the second conveyor 2 correctly. In other words, the lugs 45 at the widthwise midportion of the article P must be positioned in the path of travel of the pushers 21 on the drive chain 11. Otherwise, it would be impossible for the pusher 21 to engage the article P to advance the same. The pushing means 54 assures accuracy in bringing the article P to the correct position. Thus when the pivotal bars 60 turn in a counterclockwise direction in FIG. 2 from inclined position to upright position, namely when the rollers 59 on the upper ends thereof shift from lower position to elevated position, the article P which has been pushed forward by the pushers 33 as already described is further pushed by the rollers 59 on its rear side, the rollers 59 thus acting to place the article P correctly on the second conveyor 2 when brought to their elevated position. Since the first conveyor 1 is employed as a branch conveyor, the articles P are usually conveyed predominantly on the second conveyor 2. Since the opening 43 is formed at the junction of the first conveyor 1 and the second conveyor 2, the article P which has been guided by the guide rails 13 may possibly be guided improperly and displaced sidewise at this position. To avoid this, the pivotal bars 60 which are normally in upright position permit the horizontally positioned rollers 59 on their upper ends to guide one side of the article P when the article passes the opening portion 43. Further only when the article P is to be transferred from the first conveyor 1 onto the second conveyor 2, a limit switch and photoelectric tube or like detecting means detect that the article is brought close to the front end of the first conveyor 1 so that the pivotal bars 60 are inclined rearward temporarily before the article P is positioned above the pushing means 54. Upon lapse of a predetermined period of time, a timer actuates the pivotal bars 60 into the foregoing operation to send out the article P.

The hydraulic cylinder 75 operates to extend the piston rod 73, which in turn brings the pivotal bars 70 of the receiving and transferring means 55 to substantially upright position as indicated in the solid line in FIG. 3, thereby permitting the rollers 69 on their upper ends to assume a substantially vertical posture. In this state, the support pins of the rollers 69 are at right angles to those of the supporting rollers 7 on the second conveyor 2, and the rollers 69 are in alignment with the supporting rollers 40 on the first conveyor 1. Furthermore, the supporting rollers 69 are positioned slightly above the supporting rollers 7 but at the same level as the supporting rollers 40 of the first conveyor 1. When retracted, the piston rod 73 inclines the pivotal bars 70 and brings the rollers 69 to a level lower than the supporting rollers 7. Before the article P is transferred from the first conveyor 1 onto the second conveyor 2, the four pivotal bars 70 are raised. Subsequently, the rollers 69 on their upper ends receive the article P sent out onto the second conveyor 2. The pivotal bars 70 are then turned in a counterclockwise direction in FIG. 3 to inclined position, namely the rollers 69 are brought from elevated position to lowered position to place the article P on the rollers 69 onto the supporting rollers 7.

As already described, it is required that at the junction of the first and second conveyors 1 and 2 the pusher 21 and lever 26 on the drive chain 11 should not project upward from the level of the supporting rollers 7 during the foregoing article transferring operation. This requirement is fulfilled by the cam means 76 shown in FIGS. 1 to 3 and FIGS. 11 and 12.

The parallel links 78 of the cam means 76 are supported on the same rods as the pivotal bars 70 and are pivotally movable in synchronism therewith. When the parallel links 78 are upright as indicated in the solid line in FIG. 3, the cam is positioned close to the drive chain 11 and is located in the path of movement of the roller 22 at the lower end of the pusher 21, whereas when the parallel links 78 are in their inclined position as indicated in the dot-and-dash line in the same figure, the cam 77 is remote from the drive chain and is positioned below the path of movement of the roller 22. Normally, the cam 77 is in its lowered position along with the rollers 69 of the receiving and transferring means 55. The article P on the second conveyor 2 therefore moves along at the junction of the first and second conveyor 1 and 2, free of interference with the cam 77 and the rollers 69 (see FIG. 11). When the article P is to be transferred from the first conveyor 1 onto the second conveyor 2 as described above, the cam 77 and rollers 69 are brought up to elevated positions at the same time. Consequently, the roller 22 on the pusher 21 rolls up along the rear slanting surface 77b of the cam 77. This movement turns the pusher 21 about the pivot 20, causing the lower projection 21b thereof to rise while conversely lowering its upper projection 21a. As a result, the tilting movement of the pusher 21 inclines the lever 26 to which the pusher is linked as at 30. While the roller 22 is rolling along on the horizontal upper surface 77a of the cam 77 at its elevated position, the pusher 21 and lever 26 remain inclined below the upper ends of the support rollers 7. When the article P sent out from the first conveyor 1 and supported on the rollers 69 is placed onto the supporting rollers 7 by virtue of inclination of the pivotal bars 70 of the receiving and transferring means 55, the cam 77 descends simultaneously, permitting the pusher 21 to rise under gravity. Thus the pusher advancing from behind the article P now stopped on the supporting rollers 7 comes into engagement therewith to advance the article. When the article P has moved past the junction of the first and second conveyors 1 and 2, the cam 77 and rollers 69 are shifted to their elevated positions to incline the pusher 21 and lever 26. At the same time, another article P subsequently discharged from the first conveyor 1 onto the second conveyor 2 is received by the rollers 69. Through the repetition of the same operation, the articles P sent forward on the first conveyor 1 are transferred onto the second conveyor 2 one after another.

During the transfer operation described, there arises a need to stop a group of articles before the junction of the first and second conveyors 1 and 2 while the articles are being sent forward on the second conveyor 2. To this end a stopper may be provided at the position before the junction. It will be apparent that in the same manner as described with reference to FIGS. 9 and 10, the advancing articles will then be brought to a halt one after another in accumulated fashion. Even in the absence of such stopper, the articles can be stopped before the junction by the cam 77 as apparent from FIG. 12. In this case, however, the spacing between the pushers 21 must be taken into consideration.

The means for receiving and transferring the articles P may alternatively comprise an endless drive chain which is positioned in the second conveyor 2 transversely thereof in alignment with the first conveyor 1 or drive rollers having axes positioned longitudinally of the second conveyor 2, such alternative means being rendered movable upward and downward with respect to the upper ends of the supporting rollers 7.

The conveyor of the accumulation type shown in the foregoing embodiment is a novel conveyor for which a separate patent application has already been filed. If a known conveyor of the accumulation type is used which is adapted to push articles from behind, special lugs can be dispensed with, so that the article to be conveyed need not be a pallet as herein shown specifically.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

What I claim is:

1. In a conveyor system having a first conveyor for conveying articles and a second conveyor disposed at one end of the first conveyor transversely thereof for receiving the articles from the first conveyor, an apparatus for controlling conveyance of articles comprising the second conveyor including a number of rotatable supporting members arranged in two rows longitudinally thereof for supporting the articles, a drive chain interposed between the two rows of supporting members in parallel thereto and positioned below the supporting members, a number of normally raised pushers tiltably pivoted, each at an intermediate portion of its length, to the drive chain at specified spacing and each having an upper projection and a lower projection, the upper projection being engageable with an article on the supporting members when in its raised position and disengageable from the article when tilted and means for tilting the pusher engaging an advancing article when the article approaches a preceding article stopped during transport; an upwardly and downwardly movable cam disposed forwardly of the first conveyor in opposing relation to the front end thereof and positioned under the drive chain of the second conveyor, the cam having a horizontal upper surface of a length approximately equal to the width of the first conveyor and downwardly slanting surfaces at its front and rear ends respectively, the cam being operable to push up the lower end of the pusher by the horizontal upper surface when moving upward to bring the upper end thereof down to a level lower than the supporting members and to bring the horizontal upper surface out of contact with the lower end of the pusher when moving downward; and means for transferring the conveyed articles from the first conveyor onto the second conveyor.

2. The apparatus for controlling conveyance of articles as set forth in claim 1 wherein the pusher is maintained in its raised position under gravity acting on the portion thereof below a pivot supporting the pusher, the lower end of the pusher projecting downward from the drive chain and being provided with a roller rollable on the cam.

3. The apparatus for controlling conveyance of articles as set forth in claim 1 wherein the pusher tilting means comprises levers disposed in front of the pushers in mating combination therewith respectively, each of the levers having an upper projection, lower projection, a roller mounted on the upper projection and rollable in contact with the under surface of the article, a rear projection extending from the upper projection toward the pusher and a link connecting the rear projection to a front projection extending from the pusher toward the lever, each of the levers being tiltably pivoted to the drive chain at an intermediate portion of its length and normally maintained in its raised position under gravity acting on the portion thereof below its pivot, whereby the pusher is rendered tiltable in operative relation to the tilting of the lever.

4. The apparatus for controlling conveyance of articles as set forth in claim 1 wherein the transferring means is disposed at the end of the first conveyor and comprises means for pushing out the conveyed articles on the first conveyor from the same conveyor toward the second conveyor and means for receiving the articles pushed out from the first conveyor by the pushing means and transferring the articles onto the rotatable supporting members of the second conveyor.

5. In a conveyor system having a first conveyor for conveying articles and a second conveyor disposed at one end of the first conveyor transversely thereof for receiving the articles from the first conveyor, an apparatus for controlling conveyance o f articles from the first conveyor, an apparatus for controlling conveyance of articles comprising the second conveyor including a number of rotatable supporting members arranged in two rows longitudinally thereof for supporting the articles, a drive chain interposed between the two rows of supporting members in parallel thereto and positioned below the supporting members, a number of normally raised pushers tiltably pivoted, each at an intermediate portion of its length, to the drive chain at specified spacing and each having an upper projection and a lower projection, the upper projection being engageable with an article on the supporting members when in its raised position and disengageable from the article when tilted and means for tilting the pusher engaging an advancing article when the article approaches a preceding article stopped during transport; an upwardly and downwardly movable cam disposed forwardly of the first conveyor in opposing relation to the front end thereof and positioned under the drie chain of the second conveyor, the cam having a horizontal upper surface of a length approximately equal to the width of the first conveyor and downwardly slanting surfaces at its front and rear ends respectively, the cam being operable to push up the lower projection of the pusher by the horizontal upper surface when moving upward to bring the upper projection thereof down to a level lower than the supporting members and to bring the horizontal upper surface out of contact with the lower projection of the pusher when moving downward; means disposed in the end of the first conveyor for pushing out the conveyed articles of the first conveyor from the same conveyor toward the second conveyor; and means disposed at the end of the first conveyor for receiving the articles pushed out from the first conveyor by the pushing means and transferring the articles onto the rotatable supporting members of the second conveyor.

6. The apparatus for controlling conveyance of articles as set forth in claim 5 wherein the pushing means includes frames disposed in the first conveyor, a rod rotatably supported by the frames transversely thereof, pivotal members fixed to the rod proximate to the opposite ends thereof respectively and extending upward, an ear extending downward from the midportion of the rod and a hydraulic cylinder having a piston rod with an end pivoted to the ear, whereby the pivotal members are rendered reciprocally movable between an upper position and a lower position with respect to the upper ends of rotatably supporting members of the first conveyor, the pivotal members being operable to push an advancing article toward the second conveyor in contact with the rear end of the article when moving upward from the lowered position so as to discharge the article completely from the first conveyor when in the elevated position.

7. The apparatus for controlling conveyance of articles as set forth in claim 5 wherein the receiving and transferring means comprises frames disposed in the second conveyor, two rods rotatably supported by the frames transversely thereof and spaced apart by a specified distance, pivotal members fixed to each of the rods proximate to its opposite ends respectively and extending upward, rollers each rotatably mounted on the upper end of each of the pivotal members, downardly extending levers each fixed to one end of each rod, a link interconnecting both the levers and a hydraulic cylinder having a piston rod with its distal end pivoted to an intermediate portion of one of the levers, the rollers on the pivotal members having their support pins positionable at right angles to those of the supporting members of the second conveyor and in alignment with supporting members of the first conveyor, the rollers further being positionable slightly above the rotatable supporting members of the second conveyor but at the same level as the rotatable supporting members of the first conveyor, the pivotal members thus being reciprocally movable between an upper position and a lower position with respect to the upper ends of the rotatable supporting members of the second conveyor to receive an article sent out from the first conveyor when in elevated position and to place the article onto the rotatable supporting members of the second conveyor in the course of downward movement from the elevated position.

8. The apparatus for controlling conveyance of articles as set forth in claim 5 wherein a pair of article discharging chains are disposed in the front portion of the first conveyor and followed by its drive chain, each of the discharging chains being equipped with at least one pusher for pushing the articles from behind.

9. The apparatus for controlling conveyance of articles as set forth in claim 5 wherein each of the first and second conveyors is provided with a pair of guide rails extending along the opposite sides of the articles to be conveyed, and at the junction of both the conveyors one of the guide rails of the second conveyor is partially removed over a distance corresponding to the space between the pair of guide rails of the first conveyor to form an opening at the removed portion, the first conveyor further including pivotal members composed of bars secured to a rod and rollers each mounted on the upper end of each bar, the rollers being horizontally positionable at the opening when the pivotal members are at an elevated position so as to cooperate with the guide rails of the second conveyor.

10. The apparatus for controlling conveyance of articles as set forth in claim 5 wherein the article to be conveyed is a pallet including lugs attached to the midportions of its four sides respectively with which the pusher is engageable from inside, guide rails each extending between each pair of the lugs opposing each other to guide rollers on levers and slider surfaces extending lengthwise and widthwise of the pallet respectively for movable contact with the rotatable supporting members of the first and second conveyors.