Patent GB-768471-A (GB)
Title: Drive unit construction for conveyor chains
IPC: B65G23/14
Filed: 1955-02-22
Abstract: 768,471. Conveyer chain drive. WEBB CO., J. B. Feb. 22, 1955 [Feb. 23, 1954], No. 5237/55. Class 104(2). A chain positioning device, for use in conjunction with a conveyer chain driving device having driving members which engage the chain, extending lengthwise in the region of the drive comprises a barrier member disposed between the driving device and the chain and having a slot to allow the passage of the driving members for engagement with the chain and a non- apertured member serving to prevent lateral displacement of the chain towards the driving device as the driving members heave the chain. A telescopic chain 10, located in a sub-floor channel drives trucks along a floor 16 by pins projecting downwardly from the trucks through a slot 17 in the floor. The chain 10 is driven by dogs 12, 12A of an endless chain 11 driven by a sprocket 13 from a reduction gear 20. The chain 11 is backed by a plate 14 which holds the chain 11 and hence the dogs 12, 12A in driving engagements with the chain 10. At the position of the sprocket 13 the chain tends to follow the dog 12A as it moves away from the driving position but by keeping the chain under tension at this point this is prevented. The chain 10 is therefore maintained under tension by a following auxiliary drive unit. An endless chain 28, provided with driving dogs 29 engaging the chain 10, is trained about an idler wheel 27 and a driving wheel 26 and is driven by an endless chain 59 connecting a sprocket 57 (mounted on the same shaft 24 as the driven sprocket 13) and a sprocket 38 (mounted on the same shaft 30 as the sprocket 26). The angle member 68 is provided with a curved end 67 on its flange 69 and a member 64, joining the lower edges of the flanges 62, 69, is provided with a curved end 66 to guide the chain 10 into the channel. At positions just before and beyond the points where the dogs 29 on the chain 28 engage and disengage the chain 10 there is provided a slotted barrier member 63, Fig. 3. The sprocket 26 is angularly adjustably mounted by means of slots 36 and bolts 35 on a driving plate 34 to respace the dogs 29 of the auxiliary drive relatively to the dogs 12 of the main drive to prevent jamming of the chain 10 between the main and auxiliary drives. The spindle 40 carrying the idler sprocket 27 is mounted on plates 42 adjustably slidable along bars 41 by a screw 46 and nuts 47 to adjust the tension in the chain 28. Overloading of the auxiliary drive is prevented by an idler sprocket 70 engaging the tension run 60 of the chain 59. The sprocket 70 is mounted on an arm 72 of a pair of arms 72, 73 pivotally mounted about a pin 76 and the arrangement is such that if the load on the auxiliary drive increases the tension portion 60 of the chain 59 tends to straighten and moves the sprocket 70 downwards to move the arm 73 downwards against a spring 82 to actuate a limit switch 85 to stop the driving motor. In an alternative arrangement shown in Fig. 7 the main drive is mounted on a floating framework. The main drive comprises a chain 98 provided with driving dogs 110 and trained about an idler sprocket 101 and a driving sprocket 99 driven by a motor 90 through a reduction gear 91. The main drive chain 98 is mounted on a frame 92, 93 movably supported on " Vee " pieces 89 engaging rollers 94 mounted on a fixed frame member 95. Reaction springs 97 are placed between the fixed frame member 95 and the movable frame members 92. The barrer member comprises two vertically spaced bars 125, the driving dogs 110 engaging the chain 10 through a slot 124 formed between the bars 125. An adjustably mounted backing bar 105, Gig. 15, placed on the inside of the chain 98 opposite the slot 124 is formed with a straight portion 148 and two inclined end portions 147, 149 arranged at a tangent to the sprockets 99, 101 respectively and joined by a curved portion 151. The curvature of the curved portion is equal to or less than the curvature of the face 180 of the dogs 110. In an alternative arrangement, Fig. 18, the straight portion 166 of the backing bar 165 is arranged so as to diverge from the centre line of the chain 10 and the driving faces of the dogs 161 have a face angle 162 equal to or greater than the angle of divergency between the bar 165 and the chain 10. In the arrangement shown in Figs. 9 and 15 the chain 10 opposite the slot 124 bears against rollers 130 mounted on the movable frame 92, 93 and the rear plate 129 member supporting the rollers 130 is engaged by a further set of rollers 143 supported on the fixed frame. Specification 677,252 is referred to.