Abstract:
An apparatus for transferring articles between a pick up station such as a conveyor and a deposit station comprising a conveyor and a transfer car which is supported for movement between the conveyor and a station. The car having interdigitating means thereon adapted to interdigitate with said conveyor when the transfer car is at a position adjacent the conveyor. The interdigitating means is supported on the car for vertical movement such that the interdigitating means may be moved upwardly to lift an article from the conveyor or the station and downwardly to lower the article on the conveyor or the station.

Description:
This invention relates to transfer systems and particularly to systems for transferring articles between a conveyor and a remote station. 
     BACKGROUND OF THE INVENTION 
     In the handling of articles which are transported from one area to another it is necessary to deposit and pick up the articles or loads. A typical situation is when articles or loads are removed from a conveyor such as a roller conveyor and transferred to a spaced location. One common system utilized is separate forklift trucks or similar devices. Such devices are not applicable to automatic storage and retrieval systems wherein accuracy is required in positioning the load to a close tolerance for pick up by an automatic device such as a computer controlled crane. Another system that has been used is to utilize a transfer car that carries a piece of the conveyor that acts both as a transporting conveyor when the car is in position adjacent the conveyor and as a carrier for holding the article or load when the car is moving to a remote station. In such a system, since the car leaves the transportation conveyor, a gap is created interrupting the flow of loads or articles. 
     Accordingly, among the objects of the invention are to provide a system wherein a transfer car has interdigitating capability with a transportation conveyor or a pick up station; which leaves no conveyor gap permitting continuous operation; wherein there is no external control source required; wherein only one drive is required for all functions of moving the car and transferring the load between the conveyor and a remote station; and wherein the system may be adapted to either pick up at a conveyor and deposit at a station or the reverse, namely, pick up at a station and deposit on a conveyor. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, one apparatus for transferring articles or loads between a conveyor and a station comprises a conveyor and a transfer car, which is supported for movement between the conveyor and a station. The car has interdigitating means thereon adapted to interdigitate with the conveyor when the transfer car is at a position adjacent the conveyor. The interdigitating means is supported on the car for vertical movement such that the interdigitating means may be moved upwardly to lift an article from the conveyor or the station and downwardly to lower the article on the conveyor or the station. The system can also be used for transfer between two stations, neither of which is a conveyor. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a part sectional plan view of a system embodying the invention. 
     FIG. 2 is a fragmentary elevational view of the system. 
     FIG. 3 is a sectional view on an enlarged scale taken along the line 3--3 in FIG. 2. 
     FIG. 4 is a fragmentary part sectional view on an enlarged scale of a portion of the system shown in FIG. 2. 
     FIG. 5 is a fragmentary part sectional plan view of a portion of the system shown in FIG. 4. 
     FIG. 6 is a fragmentary sectional view taken along the line 6--6 in FIG. 5. 
     FIG. 7 is a fragmentary sectional view taken along the line 7--7 in FIG. 5. 
     FIG. 8 is a fragmentary view of a portion of the system shown in FIG. 5. 
     FIG. 9 is a fragmentary sectional view taken along the line 9--9 in FIG. 8. 
     FIG. 10 is a fragmentary sectional view taken along the line 10--10 in FIG. 8. 
     FIG. 11 is a part sectional elevational view of a part of the system shown in FIG. 4, showing the parts in a different operative position. 
     FIG. 12 is an elevational view of a portion of the system. 
     FIG. 13 is an end view of the same. 
     FIG. 14 is a side elevational view of a modified part of a system. 
     FIG. 15 is an end view of the same. 
     FIG. 16 is a diagrammatic plan view of a portion of the system. 
     FIGS. 17A-E inclusive are diagrammatic sectional views showing the relative positions of the parts when a transfer car is at a pick up position. 
     FIGS. 18A-E inclusive are schematic sectional views showing the relative positions of the parts when the load has been lifted by the transfer car at the pick up station. 
     FIGS. 19A-E inclusive are schematic sectional views showing the relative positions of the parts as the transfer car with the lifted load thereon travels to the deposit position. 
     FIGS. 20A-E inclusive are schematic sectional views showing the relative positions of the parts as the transfer car is stopped at the deposit position. 
     FIGS. 21A-E inclusive are schematic sectional views showing the relative positions of the parts as the load is lowered at the deposit position. 
     FIGS. 22A-E inclusive are schematic sectional views showing the relative positions of the parts as the transfer car lowers the load at the deposit position and begins travel toward the pick-up station. 
    
    
     GENERAL DESCRIPTION 
     Referring to FIGS. 1 and 2, the system includes a roller conveyor 30 comprising a plurality of longitudinally spaced laterally extending rollers 31, a pick-up station 32, and a transfer car 33 movable along tracks 34, 35 between the conveyor 30 and station 32 to pick up a load from the conveyor 30 and deposit the load on station 32. 
     At the area where the tracks 34, 35 underlie the conveyor 30, portions of the side rails of the conveyor are cut away as at 36, 37 to permit rollers 38 on the car 33 to interdigitate. As presently described, the transfer car 33 includes means for raising and lowering the rollers 38 so that the rollers 38 can be raised relative to the rollers 31 to lift an article or load from the conveyor 30 and transport it to a deposit position or station 32 wherein the rollers 38 can be lowered to deposit the article or load onto the spaced posts 32a at the deposit position 32. The spaced posts 32a permit movement inwardly of the lift portion of a storage crane that may form part of a storage and retrieval system. Alternatively, a conveyor can be provided at the station 32 for receiving the load and moving it to another destination. 
     As presently described, power for moving the transfer car as well as for raising and lowering the rollers 38 is obtained from a single motor 39. 
     The conveyor may have the rollers 31 thereon driven in any conventional manner as by sprockets 39&#39; and chains 40. The conveyor drive preferably is of the type that can be readily stopped so that the load thereon is ready for pick-up at the pick-up station. The conveyor may comprise a plurality of separately driven sections which are individually controlled so that no load will be moved into position for pick-up by the transfer car if there is already a load in position to be picked up. 
     DESCRIPTION 
     Referring to FIGS. 1-13, the transfer car 33 comprises a lower frame assembly 41 and an upper frame assembly 42, each of which is H-shaped. The lower frame assembly 41 includes wheels 43 at the extremeties of the sides thereof which are rotatably mounted for free rotational movement on axles 44 (FIG. 7). A cam 45 is fixed to each axle 44 and is engaged by a cam follower 46 having a roller 47 thereon engaging the periphery of the cam 45 and fixed to its upper end to the upper frame assembly 42. When each cam 45 is rotated, as presently described, the respective cam follower 46 is raised and lowered to raise and lower the upper frame assembly 42 and, in turn, the interdigitating rollers 38 mounted thereon. Cams include stops 45a. 
     By this arrangement, the axles 44 are free to rotate, when the car is not traveling to permit lifting and lowering the top frame assembly 42 by rotating axles 44. In addition, the wheels 43 are free to rotate and the cams 45 are able to remain fixed holding the top frame assembly 42 lifted or lowered while the car is traveling. 
     A main shaft 48 is mounted in the center of the lower frame assembly for rotation in pillow blocks 49. Sprockets 50, 51 are fixed on the shaft 48 and chains 52, 53 are trained thereon and extend to sprockets 54 fixed on axles 44 to transmit lifting and lowering forces to the cams 45. As shown in FIG. 11, idler sprockets 70 rotatably mounted on fixed shafts and idler sprockets 71 mounted on an adjustable lever 72 are provided in engagement with chains 52, 53 in order to maintain tension thereon. 
     In addition, sprockets 55 are fixed on the center of shaft 48. One end of a chain 56 is connected to sprockets 55 and is trained over a sprocket 57 which is driven by the motor 39 by a chain 58 trained over sprockets 59 on the shaft of the motor and sprockets 60 on the shaft of the sprocket 57. The other end of the chain 56 passes over an idler sprocket 61 adjacent the station 32 and is connected to a sprocket 62 also fixed on the shaft 48. 
     Cams 63, 64 are fixed to shaft 48 and are engaged by pivoting latches 65, 66 along the path of the transfer car to stop the car and permit rotation of the shaft 48 at the conveyor and station so that the chain 56 will function to rotate the shaft 48 and raise or lower the upper frame assembly and, in turn, the interdigitating rollers 38. As the transfer car approaches the end of its movement, it engages shock absorbing pads 73. Guide rails 74 guide the load on the transfer car. 
     Each of the latches 65, 66 is identical in construction and, for purposes of clarity, only one will be further described. Referring to FIGS. 12 and 13, latch 65 comprises a base 75 and a bracket 76 mounted for pivotal movement about a horizontal axis defined by a shaft 77 that is supported between stanchions 78, 79 on the base 75. The bracket 76 includes a counterweight portion 80 that normally holds the bracket in upright position. A cam or guide bar 83 extends horizontally and, as shown in FIG. 1, provides a surface to permit deflecting of the latch counter-clockwise to the broken line position as shown in FIG. 13 as the transfer car moves to a pick-up or load station. A roller 81 is mounted about a horizontal axis on an upstanding wall 82 of the bracket 76 and is adapted to engage the periphery of the cam 63, 64 or as the case may be, to prevent movement of the transfer car away from one station toward another station (FIG. 6). 
     OPERATION 
     The operation may be more readily understood by reference to FIGS. 16-23. FIG. 16 is a schematic plan view of the transfer car showing various section lines AA - EE inclusive. FIGS. 17A-E, FIGS. 18A-E, FIGS. 19A-E, FIGS. 20A-E, FIGS. 21A-E, 22A-E and FIG. 23 are schematic section views at the section lines AA - EE inclusive at the various portions of the operation of the system. 
     As shown in FIGS. 17A-E, when the transfer car 33 is at the pick-up station in position to pick-up a load from the conveyor, the wheel cams 45 are such that the rollers 38 are in the lowered position. The lowering cam 63, lowering sprocket 55, lifting sprocket 62 and lifting cam 64 are in the position shown with the roller 81 of latch 65 engageing the periphery of the lifting cam. 
     Thus when the motor is energized to move the chain in the direction shown by the arrows in FIG. 18D, the various parts are moved in the direction of the arrows and the sprocket 62 functions to rotate the axle 48 and the lifting cam 64 to, in turn, drive the wheel cams 45 lifting the upper frame and, in turn, the rollers 38 to a position when a load will be lifted off the conveyor. 
     Continued drive to the chain 56 in the same direction will cause the cam 64 to rotate until the roller 81 on the pivoting latch 65 reaches the flat of the cam 64 so that continuing movement of the chain 56 will now move the transfer car toward the deposit position or station. This condition of movement toward the deposit station is shown in FIGS. 19A-E. 
     As the transfer car reaches the deposit position, the pivoting latch 66 is initially deflected out of the way and then the roller 81 thereon is permitted to engage the periphery of the lowering cam 63, with the remaining parts having the relative positions shown in FIGS. 20C, D and E. 
     When the motor drive is reversed to drive the chain 56 in the opposite direction, the chain rotates shaft 48 through sprockets 55 and initially the roller 81 on pivoting latch 66 prevents movement of the transfer car so that the axle 48 will be rotated to rotate, in turn, the wheel cams 45 and lower the rollers 48 depositing the load at the deposit station (FIGS. 21A-E). Continued movement of the chain 56 in the same direction will bring the roller 81 to the position where it clears the cam 63 so that the transfer car will then move toward the pick-up station. 
     The condition of the parts as the transfer car moves toward the pick-up station is shown in FIGS. 22A-E. 
     Although the operation has been described in connection with movement between a conveyor and a station, it can be understood that the apparatus can also be utilized to transfer between two stations or from a station to a conveyor or between conveyors. 
     The operation of the motor to cause lifting and lowering movement can be manually controlled but, in the preferred arrangement, the control is automatic so that when a load and transfer car are at the pick-up station, indicated by closing of limit switches LS1 and LS2, the motor is operated to raise the load and move the transfer car to the deposit station; when the transfer car reaches the deposit station, as indicated by closing of limit switch LS3, the motor is reversed to lower the load and deposit it at the pick-up station; when the load has been deposited, as indicated by closing of limit switch LS4, the motor movement is reversed to return the transfer car to the pick-up station. In addition, it is preferred that in order to provide for greater capacity, a limit switch LS5 be provided in the path of the elevated load as it moves from the pick-up station to the deposit station so that the conveyor can be stopped to deposit another load at the pick-up station while the transfer car is carrying a load to the deposit station. 
     In the modified form of upper frame shown in FIGS. 14 and 15, the rollers 38 are eliminated and the support bars 38a only are provided for supporting the load. Such an arrangement can be utilized where the load is light and can be centered by the guide rails easily as the transfer car moves from the pick-up station to the deposit station. 
     However, where the load is quite heavy and it is necessary to position the load accurately relative to the deposit station for pick-up by an automatic device such as a crane, the rollers 38 are preferred. 
     As the transfer car moves toward the deposit station from the pick-up station, the guide bars 83 guide the load and accurately position it so that it can be deposited properly at the deposit station and any automated device such as a crane will readily be able to pick it up.