GB761485A - Improvements in or relating to electric intervalometers - Google Patents

Abstract

761,485. Actuation of switches; switches held set and freed mechanically. TEDDINGTON AIRCRAFT CONTROLS, Ltd., [formerly TEDDINGTON CONTROLS Ltd.]. May 3, 1955 [Feb. 11, 1954], No. 4077/54. Class 38(5) A device for sending impulses at predetermined intervals comprises a constant speed motor driving a pair of discs, a ball clamped between the discs and mounted in a carrier normally rotating with the discs, one disc having a recess forming a seating for the ball, a switch actuating member arranged in the path of an abutment on the carrier so as to stop the carrier and close an impulsing switch. continued rotation of the discs causing the ball to ride out of its seating and so force one disc axially to operate a reversing switch for the motor. The discs 5, 6 are carried by a tube 4 driven from the motor 2 over gearing 3. The disc 5 is fast on the tube, but disc 6 is urged to the left, Fig. 2, by a rod 10 which is acted on by a spring of a snap action reversing switch 15 over a lever 12. Three balls 16 are clamped between the discs and normally rest in recesses 18 in disc 5. The ball carrier 17 has an abutment which co-operates with the impulsing switch 20 and arrests rotation of the carrier 17, so that the disc 6 is forced to the right by balls 16 and the reversing switch 15 is actuated by the rod 10 and lever 12. When the motor reverses, the carrier 17 is carried round with the discs in the reverse direction, the balls 16 remaining out of the recesses 18 until the abutment 19 engages an adjustable stop 24 and stops the carrier 17. Further movement of the discs allows balls 16 to reenter recesses 18 and disc 6 to move to the left, with consequent reversal of switch 15. The stop 24 is an arcuate piece carried by an adjusting knob 25 which has to be depressed to disengage a clutch 28 before it can be rotated. Such depression causes a pin 31 to open contacts in the motor circuit during the adjustment. Rotation of the knob to an "off" position causes a finger 33 to engage a ramp 34 and hold the knob inwardly to retain the plunger 31 depressed and hold open said contacts. Specification 642,878 is referred to.