GB854773A - Uni-directional transmission devices - Google Patents

Abstract

854,773. Ratchet clutches. NAPIER & SON Ltd., D. April 27, 1959 [May 20, 1958], No. 16194/58. Class 80 (2). A ratchet clutch of the Legge type, comprising a driving-shaft 10 formed with a quick-pitch thread 12 supporting an intermediate clutch sleeve 13 screwed leftwards of Fig. 1 to engage clutch teeth 14 with clutch teeth 15 on a driven shaft 11, has a friction coupling 16, 18 between the driving and driven shafts to initiate screwing of the clutch sleeve along the driving-shaft on over-running, the coupling consisting of a radial flange 16 fast with the driven shaft engaged frictionally by a dished spring washer 18 carried on a coupling sleeve 19 slidably mounted by axial splines 20 upon the clutch sleeve 13 and also connected through camming teeth 25, 26 with a flange 27 fast on the driving-shaft. The arrangement is such that at the commencement of over-running in the clutch-engaging direction between the driving and driven shafts 10, 11, the camming teeth 25 on the coupling sleeve 19 ride up the camming teeth 26 on the flange 27 and the coupling sleeve slides leftwards of Fig. 1 until the flat tips 28 of the camming teeth engage, the force frictionally engaging the dished spring washer 18 and the radial flange 16 thereby being increased. Conversely, when the clutch is disengaged, the camming teeth 25, 26 and the coupling sleeve 19 are restored to the rest position, thus reducing the friction between the coupling parts 16, 18 so that less wear takes place. As shown, the clutch teeth 14, 15 have inclined flanks to one side in order to facilitate their engagement.