Transfer mechanism for sheet material

Abstract

Sheets of paper having fabric sections used in the making of garments attached thereto are delivered from a machine onto a discharge tray. These sheets are grasped, one at a time, by the transfer mechanism of the invention and carried from the tray to a nearby table where the sheets are placed in an orderly pile or stack. Manual manipulation of the sheets is avoided. The transfer mechanism is track-mounted and has a main traversing power cylinder and a clamping jaw power cylinder which are operated in properly timed sequence by associated electrical control means. The invention may be utilized for transferring a variety of types of lightweight flat materials.

Description

BACKGROUND OF THE INVENTION

Devices are known in the prior art for handling or stacking sheet material without manual manipulation. Some examples of the patented prior art are present in U.S. Pat. Nos. 1,378,886; 3,618,546; 3,729,190 and 3,747,920. The present invention constitutes an improvement and simplification of the prior art mechanisms for transferring sheet material and, more particularly, the invention comprises an apparatus for efficiently handling and transferring such material in a particular environment without interfering with surrounding factory operations and without occupying floor space.

Toward this end, the sheet transfer apparatus embodying the invention is supported on and operated from an out-of-the-way overhead track in a garment manufacturing plant or the like where floor space is at a premium and available aisleways may not be blocked by bulky apparatus. This is a main distinguishing feature of the invention over the known prior art transfer mechanisms which are customarily floor-mounted on rather bulky supports and tend to be complicated and excessively costly.

In this invention, a narrow arm structure depends vertically from a small carriage which travels on an elevated track which may be slightly inclined. The carriage and arm are traversed on a linear path by a main cylinder which is mounted close to the track and above the heads of workers and surrounding machinery. At its lower end, the arm structure mounts a material gripping means in the form of padded gripping jaws, one of which is powered by a second air cylinder mounted on the arm structure. The gripping means is compact and simplified and has the ability to grasp individual sheets on a discharge tray by reaching into a notch provided in such tray. The forward movement and return of the mechanism carriage on the track and the cyclical operation of the gripping means is under control of electrical control devices including track-mounted limit switches. Other control components of the system are also overhead near the track so as not to obstruct factory operations.

Other features and advantages of the invention will become apparent during the course of the following detailed description.

BRIEF DESCRIPTION OF DRAWING FIGURES

FIG. 1 is a general perspective view of the transfer mechanism embodying the invention and depicting the relative locations of component parts thereof.

FIG. 2 is an enlarged fragmentary perspective view of clamping jaws and associated elements employed in the transfer mechanism.

FIG. 3 is a fragmentary side elevation of the mechanism.

FIG. 4 is a front elevational view of the mechanism taken at right angles to FIG. 3.

FIG. 5 is a schematic view showing a pneumatic control circuit with electrical control components in block diagram form.

FIG. 6 is a schematic view of electrical control means.

DETAILED DESCRIPTION

Referring to the drawings in detail wherein like numerals designate like parts throughout, the numeral 15 designates an overhead track or rail which is preferably constructed in the form of an inverted T in cross section, as best shown in FIG. 4. This track is suitably fixedly supported well above the heads of workers and surrounding machinery in a garment factory or the like where the invention is utilized. The track 15 forms the primary support and guidance means for the invention including all of its major components so that all of these components are well above the factory floor and out of the way to enhance safety and prevent the occupying of floor space by the invention.

The track 15 is mounted above a machine 16 in the factory room which produces and feeds forwardly relatively large paper sheets 17 having attached thereto fabric components 18 in a variety of shapes and sizes to be used subsequently in the production of garments. As the sheets 17 emerge from the machine 16, they arrive one at a time on the bed 19 of a discharge tray having a notch 20 in its forward end ahead of the machine 16. The overhead track 15 extends for a substantial distance forwardly from the tray 19 and is preferably slightly inclined so as to gradually increase its height away from or longitudinally of the tray 19, as best shown in FIG. 1. The track 15 could be level and, if so, the invention would still be fully operative. A level table 21 of somewhat lesser height than the discharge tray 19 is mounted forwardly thereof and directly under the track 15. This table receives from the transfer mechanism each sheet 17 as the latter is grasped within the notch 20 and transferred by the mechanism from the tray 19 onto the table 21. The successive sheets thus transferred by the mechanism are neatly stacked on the table 21 and are not touched by the human hand during the transfer procedure.

The transfer mechanism further comprises a carriage 22 including side plates 23 which straddle the track 15 as shown in FIG. 4. Pairs of rollers 24 journaled on the inner sides of plates 23 engage the top faces of the horizontal track flanges for the support and guidance of the carriage along the track. The vertical arm structure consisting of a vertical bar 25 and a converging brace bar 26 secured thereto at its lower end is secured rigidly to the carriage 22 below the plane of the track 15 as by bolt and bracket means 27. The vertical arm structure is narrow and located adjacent to one of the carriage side plates 23 as shown in FIG. 4. It extends downwardly below the track 15 to a point near the level of the notch 20 in tray 19 which is somewhat above the level of the table 21.

The carriage and vertical arm structure constitute a unit which is traversed in opposite directions along the track 15 toward and away from the discharge tray 19 by a long overhead pneumatic cylinder 28 suitably suspended near the bottom of the track 15 by any convenient means. The cylinder 28 has its axis parallel to the track 15 and includes a piston rod 29 which is attached directly to an end plate 30 of the carriage 22. Extension of the rod 29 from the cylinder 28 moves the carriage toward the tray 19 and retraction of the rod into the cylinder moves the carriage away from the tray 19 and across the table 21.

At the lower end of the vertical arm structure, there is provided a power-operated clamping or gripping jaw structure which may enter the notch 20 of the tray 19 and grasp each sheet 17 individually and transfer such sheet from the tray 19 onto the table 21 on top of other sheets which have been similarly transferred. This clamping jaw structure consists of an upper rigid jaw plate 31 extending perpendicular to the vertical bar 25 and held fixed in relation thereto by a bracket 32. The bracket is firmly attached near the lower end of the vertical bar 25 and also to a short auxiliary bar 33 at the forward side of the bar 25 near its lower end portion. A coacting movable jaw plate 34 is arranged below the fixed jaw plate 31 and pivotally attached at 35 to side brackets 36 which depend from the fixed plate 31. The lower jaw plate 34 is thus adapted to swing vertically toward and from the upper plate 31 about the pivot axis 35. Upstanding lugs 37 on the rear of the movable jaw plate 34 and at its transverse center receive between them an adjustable extension link 38 pivoted thereto by a pin 39.

The adjustable link 38 has a screw-threaded connection at 40 with an extensible and retractable rod 41 of a relatively small pneumatic cylinder 42 supported on a pivot element 43 secured to the vertical bar 25 near and above its lower end. This second pneumatic cylinder controls the opening and closing of the jaw structure which grasps and transports the sheets 17 from the tray to the table. Both of the jaw plates 31 and 34 have their inner faces lined with thick pads 44 of foam rubber or similar material and this soft material engages the sheets 17 while the clamping jaws are projecting into the notch 20 of tray 19.

The mode of operation of the sheet transfer mechanism is very simple and involves the movement of carriage 22 and the depending arm structure toward the tray 19 while the jaw plates 31 and 34 are separated. This movement of the carriage 22 is caused by extension of the piston rod 29 from cylinder 28. The opening of the clamping jaws is produced by the extension of piston rod 41 as depicted in broken lines in FIG. 3. When the open jaws enter the notch 20, they are caused to close on one of the sheets 17 which is lying across this notch on the tray 19, such sheet having been discharged from the machine 16. The carriage 22 will be at rest as the jaws close upon the sheet to grip it due to retraction of the rod 41. The carriage 22 is now moved reversely on the track 15 by retraction of the rod 29 so as to transfer the particular sheet 17 from the tray 19 to the table 21. During this movement, the carriage 22 is moving upwardly on the preferably inclined track 15 so as to lift the sheet 17 slightly as it is transferred across the table 21 and across the underlying stack of sheets 17 which may already be on the table 21. This lifting of each sheet during its transfer to the table allows the paper sheets to pile up on each other to a considerable height, when dropped by the clamping jaw.

When the proper transfer distance has been traversed by the carriage 22, a first limit switch 45 mounted on the track 15 will be tripped by the carriage 22 to open the clamping jaws so as to drop the transported sheet 17 onto the table 21 at the proper point. Immediately following this, the carriage will engage and trip a second limit switch 46 also mounted on the track 15 which will initiate reverse movement of the rod 29 and the return of the carriage 22 toward the tray 19 while the clamping jaws remain open, preparatory to transferring the next sheet from the tray to the table.

FIG. 5 of the drawings shows schematically the pneumatic control system for the two operating cylinders 28 and 42 as well as the associated electrical controls. In this figure, air from a remote compressor is delivered through a line 47 to a regulator 48 and filter 49, from which the air is delivered by lines 50 and 51 to the inlets of control valves 52 and 53 for the respective pneumatic cylinders 28 and 42. These two cylinders are conventionally connected to the valves 52 and 53 as shown in the diagram. The two valves 52 and 53 are operated by electrical solenoids 54 and 55 whose operation effects the reversing of the two valves at proper times to produce the required extension or retraction of the rods of the two cylinders which, in turn, control the movement of the carriage 22 and the opening and closing of the jaws 31 and 34, as described.

More specifically, the electrically controlled sequence of operations carried out by the mechanism are as follows, referring to FIGS. 5 and 6. 120 volts AC is applied to the system at lines 56 and 57 and the voltage is stepped down to approximately 24 volts by a transformer 58. Piston 29 of pneumatic cylinder 28 is fully extended in the ready position. Gripping jaws 31 and 34 are separated and are at rest in the notch 20 of tray or bed 19 waiting for one of the sheets 17 to be transferred. The sheet 17 is emitted from the machine 16 onto the tray 19 and slides down this inclined tray actuating a microswitch 59 suitably mounted within the notch 20, in turn activating a relay 60 in the overhead electrical control box. This immediately closes contacts 61 and 62. Since the limit switch 45 is normally closed, relay 63 is energized, therefore closing contacts 64 and 65.

Contact 65 now energizes solenoid 55, actuating valve 53, energizing cylinder 42 and causing the power-operated gripping jaws to close upon and grasp the sheet 17. Simultaneously, contact 62 energizes relay 66 since limit switch 46 is in a normally closed position. Relay 66 closes contact 67 and contact 68, thereby energizing solenoid 54 which closes valve 52 and causes the piston rod 29 to retract into cylinder 28. In retracting, the sheet 17 is pulled off of the microswitch lever in notch 20 which allows the contact to open, de-energizing relay 60, opening contacts 61 and 62. However, relays 63 and 66 are still energized due to contacts 64 and 67 remaining closed.

As piston rod 29 retracts, pulling carriage 22 approximately sixty inches along the track 15, it will strike limit switch 45, opening the contact of this switch and de-energizing relay 63 which opens contacts 64 and 65, de-energizing solenoid 55 and allowing the jaws 31 and 34 to drop the particular sheet 17 on the table 21.

Following this, an additional retraction of the carriage 22 approximately ten more inches causes it to strike limit switch 46, opening the contacts thereof and terminating the stroke of piston rod 29 by de-energizing relay 66, opening contacts 67 and 68, which in turn de-energizes solenoid 54, allowing cylinder 28 to again extend the rod 29 and carriage to the ready position to transport the next oncoming sheet.

The mechanism is simple and reliable in operation. It is very efficient and takes up an absolute minimum of space in a factory or the like, as previously explained. It has a full range of adjustments and is sufficiently sturdy to withstand all normal usage over a great period of time and with minimum maintenance.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

Claims

I claim:

1. A sheet material linear transfer and stacking apparatus comprising an overhead guide and support track positioned at an elevation well above the heads of workers on a factory floor or the like, a carriage mounted on said track and movable in opposite directions thereon toward and away from a source of sheets requiring transfering and stacking at a new location spaced from the source, a depending substantially vertical arm structure secured to the carriage and movable therewith along said track, a sheet gripping means carried by the lower end of the arm structure at an elevation to engage sheets at said source and transfer them to said new location, said sheet gripping means comprising a relatively stationary upper jaw fixedly secured to the arm structure substantially at right angles thereto and projecting forwardly thereof, and a lower cooperating vertically swingable jaw below the fixed jaw and pivotally secured to the arm structure, a first fluid-pressure operated cylinder unit on the arm structure having a connection with said vertically swingable lower jaw to shift the latter between open and closed positions with relation to the upper fixed jaw, a second fluid-pressure operated cylinder unit mounted adjacent to and lengthwise of said overhead track and having a connection with said carriage to reciprocate the carriage on the track, a pair of solenoid valves operatively connected with said first and second named cylinder units to cyclically control the operation thereof, a pair of electrical limit switches on said overhead track and spaced apart longitudinally of the track and both having actuators in the path of movement of the carriage, said limit switches electrically connected with said solenoid valves in such a way that engagement of said carriage with the actuator of one limit switch while moving in one direction causes opening movement of said lower jaw by the first-named cylinder unit followed by a reversal of the direction of movement of said carriage on said track by the second cylinder unit in response to engagement of the carriage with the actuator of the second limit switch, and another switch mounted adjacent said source of sheets and electrically coupled with said solenoid valves in such a way that successive actuations of the last-named switch by successive sheets at said source produces closing of the lower jaw by the first cylinder unit and gripping of each sheet and substantially simultaneous retraction of said carriage from said source and toward said new location by said second cylinder unit.

2. The structure of claim 1, wherein said overhead guide and support track is inclined upwardly and away from said source at a shallow angle to the horizontal.

3. The structure of claim 2, and a pair of relatively thick compressible pads lining the opposing faces of said jaws.