CONVEYOR DRIVE UNIT

Abstract: A drive unit (58) for a roller-type conveyor system which comprises a drive gear (80) mounted on a drive shaft (68) within heat sink plates (60,62) and driving a number of pinion gears (82) connected to a pinion shaft (84) each of which is connected to a roller by crimping with a flexible shaft. Each pinion shaft (84) is completely supported within the heat sink plates (60,62). A tangential drive frangible sprocket wheel (90) is directly connected to the drive shaft (68). The mounting plates (60,62) relieve heat generated from the drive shaft (68) and the frangible sprocket wheel (90). A number of transport mechanisms containing rollers and a drive unit (58) as just described are mounted together to form a conveyor system.

Description: Background of the Invention This invention relates to a drive unit for an article transfer system having a plurality of parallel rollers disposed in a planar array and forming a conveyor; a drive shaft having a sprocket wheel disposed at one end thereof; a drive gear fixed to said drive shaft intermediate the ends thereof; and a plurality of pinion gears disposed in a circular array around said drive gear to be driven thereby, said pinion gears being mounted on pinion shafts, said rollers being operatively connected to said pinion shafts. An article transfer or conveying system with separate drive systems is described in US-A-4,313,536. The separate drive systems allow flexibility in controlling the movement of articles. In this known drive system, a drive shaft with a gear and a system of pinion gears driven thereby are mounted on thin mounting plates. The pinion gears drive rigid shafts which, in turn, are connected to the rollers via flexible shafts. The drive shaft is enclosed within bushings located between the thin mounting plates. Thus, heat generated in the rotating elements, especially the drive shaft and the sprocket wheel, of the drive unit of the above-cited patent cannot be dissipated by the mounting plates. The heat is, therefore, retained in the unit, possibly leading to the annealing or weakening of the affected elements. It is the object of the present invention to provide a drive unit for an article transfer system that avoids too high temperatures, generated by the sprocket means and the drive shaft. This object is achieved in that said drive shaft is journalled for rotation in a pair of spaced apart heat sink mounting plates made of metal and extends at one end thereof through one of said plates; the ratio between the thickness of each of the heat sink plates and the diameter of the drive shaft is 1:1 or 1:2 (plate thickness : shaft diameter); said sprocket wheel is fixed to said one end of said drive shaft; said drive gear is fixed to said drive shaft intermediate said plates; and said pinion shafts are journalled for rotation in said heat sink plates. The heat sink means according to the inventive drive unit dissipate heat produced from the sprocket means and the drive shaft during operation. This avoids damages caused by too high temperatures. In one embodiment of the invention the mounting plates have internally protruding bosses for providing additional support to said drive shaft. Preferably the heat sink mounting plates are made of a low friction bronze. Brief description of the drawings Figure 1 is a side elevational view of a drive unit in accordance with the prior art; Figure 2 is a cross-sectional view of the drive unit of Figure 1, including an illustration of an associated chain for driving the sprocket wheel and an associated bolt for mounting the drive unit; Figure 3 is a side elevational view of an improved conveyor drive unit in accordance with the present invention showing the mounting plates and sprocket means mounted on a drive shaft; Figure 4 is a partial cross-sectional view in accordance With the present invention showing at least one associated crimped shaft mounted on the mounting plates, and a sprocket means pinned on the drive shaft; and Figure 5 is a perspective view of the improved conveyor drive unit in accordance with the present invention. Description of the preferred embodiments Attention is first directed to Figure 1 which shows a drive unit as shown in US-A-4,313,536, generally referred to by reference number 1. The drive unit 1 has mounting plates 3, 5, 7 and 9 spaced apart by spacers 11, 13 and 15. A plurality of pinion shafts 18 are mounted on mounting plates 3, 5, 7 and 9. A drive shaft 24 is mounted on the mounting plates 3, 5, 7 and 9 and accommodates a sprocket wheel 26. Thrust washers 28 and 30 adjacent to the sprocket wheel 26 are further mounted on the drive shaft 24. A spacer or bearing 31 is seated on the drive shaft 24 adjacent the thrust washer 28. Thrust washer 30 is biased against sprocket wheel 26 by spring 32 which bears against washer 34 which, in turn, is secured to drive shaft 24 by means of bolt 36. As more clearly shown in Figure 2, one end of each pinion shaft 18 is bored and squared to receive a flexible shaft 38. Each flexible shaft 38 is connected to a conveyor roller (not shown). The drive shaft 24 rides in bushing 39 mounted between mounting plates 5 and 9. Drive gear 40 is affixed to drive shaft 24 by means of a key 42. Disposed in a circular array for meshing around drive gear 40 are a plurality of pinion gears 44 which are fixed to pinion shafts 18. Mounted between mounting plates 5 and 9 are bushings 46 for accommodating the pinion shafts 18. A pair of holes are drilled through drive shaft 24 on either side of the sprocket wheel 26 and pins 48 and 50 are inserted therethrough over which thrust washers 28 and 30 are inserted. Thus, thrust washers 28 and 30 are mounted on drive shaft 24 in a manner wherein they are fixed relative to the rotation of the drive shaft 24, but at least one of the thrust washers 28 and 30 is axially movable on the drive shaft 24. The sprocket wheel 26 causes the thrust washers 28 and 30 to begin turning when a given force is applied by pressing the thrust washers 28 and 30 against the sprocket wheel 26. Once motion has begun, the thrust washers 28 and 30 are forced against the sprocket wheel 26 and remain turning. The pinion shafts in the unit of US-A-4,313,536 are mounted on the thin mounting plates 3, 5, 7 and 9 while the drive shaft is enclosed within bushing 39. Thus, the rotating drive shaft 24 and the sprocket wheel 26 generate heat which cannot be dissipated by the thin mounting plates 3, 5, 7 and 9 thereby retaining the heat therein which can lead to the annealing or weakening of the aforesaid elements. Figure 3 shows the improved conveyor drive unit of the present invention, generally designated by reference number 58. The conveyor drive unit 58 comprises heat sink plates 60 and 62 and spacers 64 and 66 therebetween. The ratio between the thickness of each of the heat sink plates 60 and 62 and the diameter of the drive shaft 68 can be 1:1 or 1:2 (plate thickness : shaft diameter). The drive shaft 68 is journalled in heat sink plates 60 and 62 which have bosses 63 and 65 which provide further support for the drive shaft 68, thereby not necessitating the enclosure of the drive shaft 68 in the bushings 39 as in the aforementioned prior drive unit. The heat sink plates 60 and 62 are preferably made of bronze known under the trademark "Oilite" which is manufactured, for example, in the Amplex Division of the Chrysler Corporation, Van Wert, Ohio. Spacers 69 and 70 are mounted between heat sink plates 74 and 76. Spacer 70 is preferably made of stainless steel and has a threaded aperture 72 passing therethrough for accommodating bolts (not shown) when the drive unit 58 is mounted. A drive gear 80 is fixed to drive shaft 68. A plurality of pinion gears 82 which are fixed to pinion shafts 84 are disposed in a circular array for meshing around drive gear 80 (see Figure 4). As better illustrated in Figure 4, the pinion shafts 84 of the drive unit 58 of the instant invention have crimped portions 86 for connecting therein flexible shafts connected to the conveyor rollers (not shown). Further, the pinion shafts 84 substantially extend between, and are journalled in, heat sink plates 60 and 62 so that the end of the pinion shafts 84 which have a higher strength than the flexible shaft connected thereto can better withstand the shear and fatigue stresses during rotation than the arrangement taught in the above-discussed US-A-4,313,536 wherein a portion of the flexible shafts 38 is rotated within the apertures passing through the mounting plate 3. Further, the crimping of the flexible shafts to the pinion shafts 84 within the confines of the heat sink plates 60 and 62 similarly provides for a stronger coupling. Further shown in Figure 4 is a sprocket wheel 90 having an integral end piece 92 With an aperture 94 passing therethrough for accommodating a pin 96 for mounting the sprocket wheel 90 onto the drive shaft 68. Spacers 64, 66, 69 and 70 have a bolt 98 with a threaded end passing therethrough for mounting thereof between the mounting plates 60 and 62. The perspective view of the improved drive unit, shown in Figure 5, illustrates the drive shaft 68 journalled for rotation in the two spaced apart heat sink mounting plates 60 and 62. Figure 5 also shows the sprocket wheel 90 fixed to one end of the drive shaft 68 and pinion shafts 84 with pinion gears 82.

Claims: A drive unit for an article transfer system having a plurality of parallel rollers disposed in a planar array and forming a conveyor; a drive shaft (68) having a sprocket wheel (90) disposed at one end thereof; a drive gear (80) fixed to said drive shaft (68) intermediate the ends thereof; and a plurality of pinion gears (82) disposed in a circular array around said drive gear (80) to be driven thereby, said pinion gears (82) being mounted on pinion shafts (84), said rollers being operatively connected to said pinion shafts (84), characterized in that said drive shaft (68) is journalled for rotation in a pair of spaced apart heat sink mounting plates (60, 62) made of metal and extends at one end thereof through one of said plates (60, 62); the ratio between the thickness of each of the heat sink plates (60, 62) and the diameter of the drive shaft (68) is 1:1 or 1:2 (plate thickness : shaft diameter); said sprocket wheel (90) is fixed to said one end of said drive shaft (68); said drive gear (80) is fixed to said drive shaft (68) intermediate said plates (60, 62); and said pinion shafts (84) are journalled for rotation in said heat sink plates (60, 62). A drive unit as defined in Claim 1, characterized in that said mounting plates (60, 62) have internally protruding bosses (63, 65) for providing additional support to said drive shaft (68). A drive unit as defined in Claim 1, characterized in that said heat sink mounting plates (60, 62) are made of a low friction bronze.

Inventors: BARKLEY, PAUL E., FAUTH, FREDERICK E. SR.
Applicants: AMERICAN BOTTLERS EQUIPMENT CO. INC.
Application year: 1987
Main classification: B65G13
IPC codes: B65G13