GB967713A - Clutch mechanism - Google Patents

Abstract

967,713. Clutch control; valves; cams. PHILADELPHIA GEAR CORPORATION. Aug. 16, 1963, No. 32417/63. Headings F2K, F2L and F2V. A shaft 33, which carries a worm that drives a nut 30 to raise or lower a valve operating spindle 27, is automatically connected to a motor-driven shaft 47 or a hand-driven shaft 37, according to which is driving, by a double clutch sleeve 59 biased by a spring 108 towards a motor-driven gear 45 and moved left into engagement with a hand-driven gear 39 by a cam 61 which is fast with a gear 38 on the shaft 37 and acts through a pivoted shift fork 52 on the clutch sleeve 52. The spring 108 normally maintains the clutch sleeve 59 in the position shown in which it is clutched at 259 to the gear 45 to provide a motor drive to the shaft 33. In the event of motor failure the shaft 33 may be driven, by hand, from the shaft 37, initial rotation of which brings the cam roller 61 into engagement with a cam block 51 pivoted at 74 to a fork 72 on the shift fork 52 and urged by a torsion spring 76 to the position shown in Fig. 7. Further rotation of the shaft 37 and cam roller 61 tilts the block 52 against the action of the spring 76 and thereafter rotates the shift fork 52, clockwise, about its pivot 169. The other end of the shift fork 52 carries rollers 62 which engage a groove 359 in the clutch sleeve 59 which is thus moved axially left to disengage the clutch 259 and engage the clutch 159, 239. If the clutch dogs 159, 239 are not positioned for precise engagement the former 159 moves right relative to the clutch sleeve 59 and are pressed into final engagement by a spring 459. During hand operation the clutch sleeve 59 is retained in its left hand position by abutments 187, 188 on a pair of spring-urged levers 87, 88 which abutments engage a projection 80 on the shift fork 52. The above retaining means also hold the cam block 51 clear of the cam roller 61 during subsequent rotation of the shaft 37. The abutment 187 is <SP>1</SP>/ 32 of an inch lower than the abutment 188 so that when the motor drives the gear 45 a cam projection 92 thereon first moves the lever 87 outward and permits rotation of the shift fork 52 until the projection 80 engages abutment 188. On further rotation of the gear 45, the cam 92 moves the lever 88 outward to release the projection 80 and permits the spring 108 to move the clutch sleeve 52 right to re-engage the clutch 259 and to rotate the shift fork to the position shown in Fig. 3.