Patent GB-298673-A (GB)
Title: Improvements in or relating to multi-leaf one-way torque-transmitting clutches
IPC: F16D41/07
Filed: 1927-07-14
Abstract: 298,673. Barrington, T. B., and Sandberg, C. P. July 14, 1927. Ratchet clutches of the kind comprising inclined struts packed in the annular space between concentric driving and driven members. The end or ends of each strut are so shaped that the line of thrust transmitted from the driving to the driven member lies at a constant or increasing distance from the clutch axis as the strut becomes more nearly radial under load. Springs urging the struts into engagement may be carried by a spacing-cage. Where the springs are independent of a cage, they preferably act along the length of the struts, to minimize friction. Fig. 20 shows a disproportionate view of a strut d<2>, in which the ends are shaped, as by grinding, into a curve or plurality of facets forming equiangular spirals F, G with a common origin at an arbitrary point E, the spirals being such that, as that strut rocks, the increase in length, due to either spiral, of the line joining the points of contact bears to the distance rolled through by that spiral the same ratio that the corresponding radius A<1>, B<1> of the outer and inner members bears to a fixed length C, this being the radius of a circle to which the line of thrust D is always tangential. The spirals may, however, be so modified that the length C increases with the' torque, and, for thin struts, may be approximated by arcs struck from centres H, J. Where the origin E is so placed that A/B=A/B<1>, the part K of the curve G becomes idle and may be a tangent to the curve G or may be omitted, the strut then being tapered (Fig. 21, not shown). Struts so formed are of minimum thickness and inertia for a given strength. Struts d, Figs. 1 and 2, occupy the space between the surfaces a<1>, b<1> of members a, b, the member a being supported by rollers b<2> on the member b, which is secured to a shaft c. The struts are guided by rivets g extending between revoluble cage rings e, f<1> and are biassed by blade or laminated springs h carried by the ring f<1> and acting on lugs d'. Each spring may bear at its outer end on one strut and at its inner end on the next strut but one (Fig. 6, not shown). The outer end of a strut may be connected by a coiled tension spring to the inner end of the next strut or next strut but one, two, three, &c. In another construction, rings m, n, Fig. 23, revoluble on bearing-rings o, o<1> and connected by halving m<1>, n<1> and rivets g<1>, are slotted out to form bevelsided pockets p for the struts d<18> and slit across between the pockets to receive tapered blade springs h<11>, lugs h<13> on which embrace parts m<3>, n<3> formed by grooving the rings. The bearing- rings o, o<1> may be omitted, the rings m, n being disposed adjacent the outer clutch member (Figs. 24 and 25, not shown). The cage rings may be secured to one clutch member, preferably the driven or non-oscillating member. Where no cage is provided, the struts d<4>, Fig. 4, may be acted on in substantially-radial directions by a spring ring h<2> engaging notches in their sides, and the ring may be kinked, as shown at h<3>, to increase its resilience. A series of concentric spring rings may be provided, each engaging every second, third, &c. strut. The ring may be divided into short lengths, each overlapping an adjacent length (Figs. 8 and) 9, not shown), or into longer lengths connecting, say, every fourth strut, there being four concentric divided rings (Figs. 14 and 15, mot shown). In either form, an. independent cage like that shown in Figs. 1 and 2 may be used to space the struts (Figs. 12, 13, and 18, not shown), or they may be spaced) by a set, or inner and outer sets, of rollers running loosely in lateral grooves (Figs. 10 and 11, not shown). Fig. 16 shows the second form, having lengths of spring h<5> - - h<8> connecting lugs on every fourth strut, the struts being spaced by rollers j, k engaging grooves in the walls of a clutch member or in a loose ring borne thereby. Where the struts are secured to the inner or outer member, that membery may have grooves forming flat or curved seats for the curved or flat ends of the struts. Fig. 19 shows struts d<20> having spiral outer ends F and rounded inner ends seating in round grooves S, the centres of which are the origins of the spirals. Directions are given for determining a point H, which is the centre of a circular arc approximating to the spiral F. Blade springs R are secured to the inner member.