GB300617A - Improved automatic locking or braking apparatus - Google Patents

Abstract

300,617. Bonal, G. de, and Masson, P. Nov. 16, 1927, [Convention date]. Locking by frictional devices.-A mechanism for frictionally locking a lever or shaft against return movement under the force or torque acting upon it, when the operating member is released while permitting such return movement with a braking action under the control of the operating member, comprises a pair of parallel plates one of which is connected to the shaft or lever and both of which can be rotated by the operating member with lost motion, the two plates having interengaging helical surfaces whereby they are forced apart against fixed braking surfaces. According to one construction, Figs. 1 and 2, a pair of plates 9, 11 rotatably mounted upon a fixed shaft 1 have interengaging cam projections or ramps 17, 18. The plate 9 is provided with a lever 10 upon which a force F is assumed to be acting. The operating handle 13 is integral with a ring 12 mounted on fixed plates 2, 22. The ring 12 has recesses 19, 20 through which project with limited play, the lever 10 and a lug 26 on the plate 11. An annular spring 14 secured at its ends to the plates 9, 11 urges the projections 17, 18 in engagement so that when the handle 13 is released the plates are forced apart under this action and that of the force F against the fixed plates 2, 22 with the interposition of washers 15, 16, thus locking the plate 9 and lever 10. If the handle 13 is moved to the left, the ring 12 engages and turns the lever 10 and plate 9 and the plate 11 is turned by the spring 14. When the handle is moved to the right. the plate 11 is turned by the engagement of the ring 12 with the lug 26 and the lever 10 is permitted to return with a braking action exerted thereon. Figs. 3 and 4 illustrate a modification bv which the locking action is obtained irrespective of the direction of the force F. The plate 11 in this case comprises two parts 11<a>, 11<b>, each comprising a pair of opposed sectors and fitting the one into the other at the central part. The faces of the projections 18a, 18b of the two plates are oppositely inclined and engage with correspondingly inclined projections on the plate 9. The spring 14 is attached to the two plates 11<a>, 11<b> and lugs 27, 28 on the plates engage notches in the ring 12. Locking is effected by the action of the projections 18a, 18b on the one or the other plate 11<a>, 11<b> according to the discretion of the force F. Fig. 8 shows a further construction in which the locking action is applied to a rotatable shaft 1<a>. The box-like member 12 carrying the handle 13 is rotatable in the fixed casing 36 and has projections 39, 40 engaging with lost motion, notches in the freely mounted plate 11 and in the plate 9 which is keyed to the shaft 1<a> and to a plate 35. The plates 9, 11 are adapted to be forced apart by cam projections thereon as in the constructions above described and thus to cause the plates 11, 35 to grip the fixed plate 36<a>. In a further construction multiple braking discs are provided. The Specification as open to inspection under Sect. 91 (3) (a) describes also a construction in which the cam projections 17, 18 are replaced by quick-pitch screw surfaces. This subjectmatter does not appear in the Specification as accepted.