GB368703A - Improvements in or relating to clutch mechanisms - Google Patents

Abstract

368,703. Sewing-machines. BRITISH UNITED SHOE MACHINERY CO., Ltd. and KEALL, F. B., Union Works, Belgrave Road, Leicester. Nov. 8, 1930, No. 33643. [Class 112.] Starting-and-stopping gear.-In curved hooked needle shoe sewing-machines of the kind described in Specification 332,313, [Class 112, Sewing &c.], and in other machines, the clutch and brake operating gearing described in Specification 720c/07, [Class 80, Mechanism &c.], is modified to prevent jamming of the operating-parts and to prevent shock. In that gearing, a swash-member carried in a slot in an axially-movable combined clutch and brake member turning with the main machine shaft causes the oscillation of a member the stopping of which causes the disengagement of the clutch and the engagement of the brake. In this Specification the said oscillating member 36 is stopped by a projection 34 on a member 32, which rises when the treadle-rod 62 is released. The brake element 2 which is engageable by the axially movable brake member is free on the machine shaft 4 and is connected by a rod 8 to an adjustable dashpot so that the element 2 is rotated slowly to stop the machine without shock and is then returned to its original position by spring means. To start the machine, the treadle is depressed and a hook 64 on the treadle-rod 62 engages a pin 38 on a trip-arm 40 turning on a pivot 42 on the brake member 2, the stop-member 32 turning on the pin 38 but being maintained in vertical position by a spring 60, which holds it against a stop on the arm 40, and by a lever 46 pivoted on a pin 48 on the arm 40. When the treadle is released, the arm 40 and stop 32 rise under the influence of a spring 66. The clutch is thus disengaged and the brake engaged, so that the brake member 2 swings, carrying with it the arm 40 so that the lever 46 rotates a tumbler 50 and passes beyond it in order that when the brake member returns the lever 46 may be depressed by the cam 54 on the tumbler to release its other end from the projection 44 on the stop-member 32. The pressure of the projection 34 on the oscillating member 36 is then maintained only by the spring 60 and is thus relieved to facilitate easy restarting. In order to ensure that the stop-member 32 may rise to stopping-position only when the member 36 is clear thereof, a spring-pressed plunger 70 projects itself below the member 36 when the arm 40 is lowered and, when the treadle is released, prevents rise of the member 32 until the plunger is pressed back by movement of the member 36 to the left. In a modified device, Fig. 7, for achieving this result, a hook 71 on the stop-member 32 is engaged by the end 72 of a lever 73 turning on a fixed pivot, the hook being released only when a suitably placed cam 77 on the rotating clutch and brake member engages a lever 76 pivoted on the treadle-rod 62, which must be released before this operation takes place.