GB1041644A - Shutter opening and closing mechanism - Google Patents

Abstract

1,041,644. Clutch-brake combinations; disc brakes. H. SUZUKI. March 4, 1964 [March 4, 1964], No. 9258/64. Headings F2C, F2E and F2L. A clutch-brake combination for a shutter operating mechanism comprises a positive clutch disc 12 fast on an input shaft 11 and having facial clutch teeth engageable with teeth on a driven clutch disc 13 which is freely rotatable on the input shaft and connected to a brake disc 14 splined to an output shaft 15 by balls 16 in opposed cam recesses in the discs 13, 14. The brake disc 14 has external coned surfaces 20 which are urged by a spring 22 into engagement with complementary surfaces on the housing 19. Initial rotation of the input shaft 11 acts through the normally engaged clutch 12, 13 to rotate the disc 13 relative to the disc 14, whereupon the balls 16 ride up the cam recesses to force the brake disc 14 right against the spring bias to disengage the brake, whereafter further rotation of the input shaft is transmitted to the output shaft 15. To permit the shutter to descend under gravity both the clutch and brake are disengaged by rotating a ring 23, whereupon balls 25 in opposed cam recesses 23a, 24a in the ring 23 and a fixed disc 24 force the ring 23 right. The rightward movement of the ring 23 is transmitted through a bearing 27 and sleeve 18 to the clutch disc 13 and brake disc 14. Rotation of the ring 23 may be effected by pulling a cable 26 which rotates a disc 34 connected through a ratchet clutch to a cam 32. A fixed stop 30 co-operates with the cam 32 so that on rotation of the latter a rod 31 fast with the ring 23 and carrying the cam 32 is moved in a clockwise direction. Rotation of the disc 34 is limited by a projection 38 thereon engaging a recess in a disc 37 fast with the rod 31. The disc 34 is returned to its initial position by a torsion spring 39.