GB834866A - An automatically disengaging overload coupling - Google Patents

Abstract

834,866. Overload release clutches. GELENKWELLENBAU G.m.b.H. Feb. 27, 1958 [May 3, 1957], No. 6351/58. Class 80 (2). An overload release positive clutch for cable winches, fire escapes, &c. comprises a driving plate 1, Fig. 1, having relatively gently sloped recesses 2 engaged by teeth 3 on an intermediate plate 4 itself provided with more steeply sloped recesses 5 engaged by teeth 6 on a driven clutch plate 7 splined to a driven shaft 9, a spring 8 biasing the teeth and recesses into engagement, overload of the driven shaft first causing the intermediate plate 4 to move axially relatively to the driving plate 1, as shown in Fig. 2, and next causing the driven plate 6 to move axially against the bias of its spring 8 relatively to the intermediate plate 4, Fig. 3, a spring-pressed ball detent 11 then engaging a groove 13 in the driven plate 7 to hold it in its disengaged position so that when the tips of the teeth 6 ride out of the recesses 5, Fig. 4 (not shown), spring 14 is able to draw the intermediate plate 4 back to the position where its teeth 3 fully engage the recesses 2 in the driving plate 1, Fig. 5, the intermediate plate 4 thus being completely free from the driven plate 7. In the preferred construction shown, the spring 14, Figs. 6, 7, is located within the driving plate 1 and the intermediate plate 4, and the driven plate 7 is exteriorly splined to slide axially within a driven sleeve 16 against the bias of its spring 8. The locking balls 11 are received in radial holes in a flange fast with the driven sleeve 16 and are engaged by an axially movable plunger 17. Under normal driving conditions, the parts take up the position shown in Fig. 6. On overload, the driven plate 7 slides within the sleeve 16 relative to the driving and intermediate plates 1, 4, as already described, so that recesses 13 therein receive the locking balls 11 urged outwardly by the spring biased axially slidable plungers 17. The clutch is held disengaged until a control ring 18 is slidden leftwardly to engage the plungers 17 and move them to a position such that the balls 11 will allow the driven plate 7 to be restored to its engaged position by the bias of its spring 8.