GB636678A - Improvements in or relating to mechanism for converting uniform rotary motion into intermittent rotary motion - Google Patents

Abstract

636,678. Snap-action switches. COLOMBIER, P. L. Nov. 27, 1946, No. 35130. Convention date, June 1, 1944. [Class 38 (v)] [Also in Group XXIV] A spring coupling applied to the operation of a multiple-position switch for advancing a driven shaft in a series of steps from a uniformlyrotating driving shaft comprises an arm 2 on a driving shaft 1 connected to an arm 6 on a driven shaft 7 through a spiral spring 3, one end of which projects at 4 and engages the arm 2, the other end being secured to a disc 40 with a projection 5 which engages the arm 6. The driven shaft carries a disc 11 with a number of recesses 12 in its periphery which are adapted to be engaged by radially-sliding, spring-loaded stops 16 mounted in a' fixed ring 15. Rotatably mounted with shaft 7 is a cam disc 8 having axially-projecting pins 9, 10 between which the arm 2 of the driving shaft 1 engages with lostmotion. The arrangement is such that on initial rotation of shaft 1, the shaft 7 being held by engagement of one of the stops 16 in a recess 12, the spring 3 is wound up until the arm 2 engages one of the pins 9, 10. The cam 8 is then rotated and actuates the operative stop 16 against its spring 18 to release the disc 11 and shaft 7, which is thereupon rotated rapidly by the tensioned spring until the following stop engages in a recess under its spring 18. With the arrangement shown of three recesses and four stops, each movement of shaft 7 is one-twelfth of a revolution. By suitable combinations of stops and recesses any desired number of movements per revolution can be obtained. The mechanism may all be housed within a comparatively flat casing, the two shafts only projecting, or within a control knob which forms the driving shaft, in which case the coupling spring may be of helical form.