581,874. Gearing for starting and stopping machinery; clutches. WARNER & SWASEY CO. July 6, 1944, No. 12945. Convention date, May 7, 1943. [Class 80 (ii)] [Also in Group XXII] A coupling device comprising a driving sleeve and a driven hub, and means to connect the members and to stop the driven member in a predetermined position after a predetermined movement thereof is characterised by the provision on the driven member of a track system having endless portions and interconnecting portions therebetween, a driving element on the driving sleeve projecting into said track and a stopping element mounted independently of the members and adapted to be projected into the track. The invention is described as applied to the moving and stopping of the main slide 32 of a lathe. Shafts 35 and 42, Fig. 2, connected by gearing with the lathe spindle drive a shaft 40 in forward or reverse direction respectively under the control of a manually operated clutch 46. Shaft 40 projects in a gear box 41 and drives a gear 49 which is integral with a sleeve 50 rotatably mounted on a shaft 55. Axially movable and freely rotatable on the shaft 55 is a gear 56 meshing with an elongated gear 58 fixed to the shaft of the screw 60 which traverses the slide 32 through the nut 61. Integral with the gear 56 is a hub portion 57 entending within the sleeve 50 and formed with a track system comprising two spaced annular grooves 62, 63 joined by a curved groove 64, Figs. 3 and 4, the central part 65 of which is parallel to the axis of the hub. The greater portions of the grooves 62 and 63 are of the same uniform depth as the curved groove 64 but the remaining portions decrease in depth towards the points where the groove 64 merges with the grooves 62 and 63. In the position shown in Figs. 2, 3 and 4, a plunger 66 projects slightly into the annular groove 62 so as to prevent any axial movement of the hub 57 and a spring-pressed plunger 53 carried in a radial boss 51 of the sleeve 50 projects into the central portion of the groove 64. If the clutch 46 is operated to drive shaft 40 from shaft 35, the sleeve 50 will be rotated and the plunger 53 will drive the hub 57, and hence the screw 60 and slide 32. After a predetermined traverse of the slide, an adjustable lug thereon depresses a member 76 which is coupled to the plunger 66 by way of rods 73 and 71 and bellcrank levers 72, 70 so that the plunger is fully depressed into the annular groove 62. On the next rotation of the hub the plunger will ride into the curved portion 64 of the track thus causing the hub to move axially and at the same time the driving plunger 53 rides along the curved track and into the annular track 63 so that the amount of drive transmitted from the sleeve to the hub decreases to zero and when the plunger 66 reaches the central portion of the curve 64, the hub is locked against further rotation. As the slide is positively geared to the hub, it also is locked. If now the shaft 40 is rotated in the reverse direction by the shaft 42, the reverse movement of the sleeve causes the driving plunger to ride again into the curved track gradually taking up the drive of the hub which is also moved axially until the plunger 66 again rides.in the annular groove 62 and the withdrawal of the lug 79 allows it to be withdrawn to its original position by a spring 77. In a modified form shown in Figs 12, 13 and 14, the slide is stopped in a predetermined position in both directions of traverse. The track on the hub 90 comprises two spaced annular grooves 106 and 107 joined by a curved groove 110 having a central portion 111 extending axially of the hub and two further spaced annular grooves 108, 109 joined by curved groove 112 similar to the groove 110 but curved in the reverse direction. In the normal position shown the plunger 88 carried by the sleeve 85 projects into the central portion of the curved groove 112 and into the grooves 106, 107 project plungers 114, 115 engaged at their lower ends by the forked arms of a pivoted lever 116. The slide feed screw is geared to a screw 100 on which is traversed a block 101 carrying adjustable lugs 104, 105 adapted to engage and rock the lever 116. Assume the shaft 40 to be rotated to traverse the slide in the forward direction. When the lug 105 engages the lever 116 the plunger 115 will be withdrawn and the plunger 114 will be fully depressed into the groove 106 and will ride into the curved groove 110 thus causing an axial movement of the hub, so that the driving plunger moves along the groove 112 until it reaches the annular track 109 when the plunger 114 reaches the straight axial portion of the groove 110 and so stops the. rotation of the hub and the forward movement of the slide. On the reverse rotation of the shaft 40 and sleeve 85, the driving plunger will ride up the curved groove 112 to the central position, the lug 105 will be withdrawn with the reverse traverse of the slide and of the block 101 and the plungers will be restored to their normal position. The slide and the block 101 will then be traversed in the reverse direction until the lug 104 rocks the lever 116 thus withdrawing the plunger 114 and fully depressing the plunger 115 which thus enters the curve 110 and shifts the hub until the driving plunger enters the annular groove 108.