GB1394920A - Torque limiting coupling - Google Patents

Abstract

1394920 Positive clutches TWIN DISC Inc 24 July 1973 [24 Aug 1972] 35181/73 Heading F2C In an overload release clutch wherein torque transmitting balls 3 carried by holes 32<SP>11</SP>... 43<SP>11</SP> in a carrier 6 normally engage recesses 32, 32<SP>1</SP>...43, 43<SP>1</SP> in driving and driven clutch discs 4, 5 urged together by springs 22, 23, the balls 3 ride out of the recesses 32, 32<SP>1</SP>...43, 43<SP>1</SP> on overload and move circumferentially into reset recesses 44...48 in the driving disc 4 which, during clutch disengagement is held at a predetermined distance from the driven disc 5 by spacing blocks 8 carried by a disc 7 which is resiliently connected to the ball carrier 6. The spacing blocks 8 abut a shoulder 71 on a driving shaft 1 and normally project into recesses 70 in the driving plate 4. When, on overlaod, the balls 3 ride out of the recesses 32, 32<SP>1</SP>...43, 43<SP>1</SP> the driving disc 4 is moved axially away from the driven disc 5 against the bias of the springs 22, 23. The following circumferential movement of the balls 3 rotates the carrier 6 and spacing block carrier disc 7 relative to the driving disc 4 so that when the balls 3 engage the reset recesses 44...49 the spacing blocks 8 abut the surface of the driving disc 4 and hold it at a predetermined distance from the driven disc 5. The spacing between the disc 4, 5 permits free relative rotation between the discs. An abutment 53 rotatably fast with the driving shaft 1 abuts the end of circumferential recesses 52, 61 in the ball carrier 6 and spacing block carrier 7 in the clutch disengaged position to prevent movement of the carrier 6 and balls 3 beyond the reset recesses. The circumferential extent of the recess 52 in the ball carrier 6 exceeds that of the recess 61 in the spacing block carrier 7 to permit relative rotation of the ball carrier 6 and spacer carrier 7 during clutch disengagement. Springs 9, 11 resiliently connecting the carrier discs 6, 7 thus bias the ball carrier 6 in a reset direction during clutch disengagement. To reset the clutch the driving disc 4 is rotated reversely or the driven disc 5 rotated forwardly whereupon the bias of the carrier disc 6 urges the balls 3 into engagement with the driven disc recesses. Further rotation of the driving or driven disc moves the balls 3 and carrier 6 relative to the driving disc 4 until the balls 3 re-engage the driving disc recesses 32<SP>1</SP>...43<SP>1</SP> and the spacing blocks 8 re-enter the recesses 70. The driving disc 4 is splined to a sleeve 13 which is itself splined to the driving shaft 1. The torque at which the clutch disengages on overload is adjusted by adjusting the position of the sleeve 13 and thus the pressure of the springs 22, 23. The balls 3 and driven disc recesses are unequally spaced circumferentially to permit clutch engagement in only one relative circumferential position of the driving and driven members.