GB608287A - Improvements in or relating to epicyclic gearing - Google Patents

Abstract

608,287. Reversing-gearing. BROCKHOUSE ENGINEERING (SOUTHPORT), Ltd., and GATISS, A. L. March 12, 1946, No. 7768. [Class 80 (ii)] In an epicyclic reversing gearing, adapted to be driven through a transmission which transmits some torque, even when the prime mover is idling, and which has no positive connection between the input and output shafts of the transmission, the reaction element of the gearing carries a dog-clutch sleeve slidable from a neutral to a gear-drive position, the sliding being accompanied by frictional retardation of the sleeve before it engages its corresponding dog-teeth and positive means to prevent such engagement until the two sets of teeth are substantially synchronised, rotation of the sleeve being permitted after engagement has taken place.. The driving shaft 10 is driven from the prime mover through a hydraulic coupling, and rotationally connected to a sun-gear 15 meshing with planet-gears 16 mounted on the planet carrier 18, which gears in turn mesh with an annulus 22 rigid with the driven shaft 21. The periphery of the planet carrier 18 is splined to drivingly engage a dog-clutch sleeve 25, having dogs 26 adapted for engagement with dogs 27 on the annulus 22 for direct drive, and axially spring-loaded dogs 29 for reverse drive. A multi-plate clutch 60 is interposed between the driving sun 15 and an annular portion of a clutch pressure plate 66, this portion being connected, with circumferential clearance by slots 78 and studs 77, to the sleeve 25. The pressure plate 66 has axially extensions 71 projecting into openings 72 in the sleeve 25, the extensions and openings being bevelled forwardly in relation to the direction of rotation of the shaft 10 as shown in Fig. 2. Engagement of the direct drive is effected by moving the sleeve 25 axially by the lever 43 on shaft .41, which may be actuated as described in Specification 608,288, the sloping edges of the openings 72 and extensions 71 co-operate to move the pressure plate axially to engage the clutch 60, and the gear is thus brought to rest against the hydraulic drag. If the torque due to the drag is high, the anti-clockwise turning of the plate 66 to allow the extensions 71 through the openings 72 will be prevented by the engagement of the sloping faces, but if the drag torque is low, the plate 66 will rotate backwards slightly and allow the sleeve to move axially for the engagement of the dogs. Thus, engagement is prevented at all speeds where there is relative rotation between the dog teeth. Engagement of reverse is produced by further sliding of the sleeve 25 into engagement with the dog teeth 29, there being insufficient clearance for a neutral position between the teeth 27 and 29. If the teeth 26, 29 meet end-on the teeth 29 move axially against the springs until the teeth 26 have disengaged from the teeth 27 of the stationary annulus, whereupon the drag causes a slight rotation of the sleeve 25 and the dog teeth engage under the axial spring pressure.