GB807182A - Shaft positioning apparatus - Google Patents

Abstract

807,182. Stopping shafts in predetermined positions. ADMIRAL CORPORATION. March 5, 1957 [March 19, 1956], No. 7242/57. Class 80 (2). [Also in Group XL (c)] Apparatus for stopping a shaft in one of a selected number of angular positions and particularly applicable to the operation of a shaft 11, Fig. 2, of a tuning device 31 of a television receiver comprises an electric motor M<SP>1</SP>the armature 32 of which is slidable axially on energization thereof to engage a gear 39, Fig. 3, with a gear 60<SP>1</SP> in a train to a gear 37 on the shaft 11. The energization of the motor is adapted to be effected by either a switch A<SP>1</SP>operated by a pushbutton 14 on the receiver or a switch D at a remote point such as across the room. The axial movement of the armature also closes a switch B<SP>1</SP> of a holding circuit for the motor so that the motor continues to drive the shaft 11 after the switch A<SP>1</SP>or D is released until a screw 53 or 54 on a plate 48 secured to the shaft, engages a spring arm 56 of a switch C arranged in series with switch B<SP>1</SP> to open this switch to stop the motor M<SP>1</SP> and release the gear 39 from the drive. The shaft 11 is thus stopped in a position determined by the screws 53 or 54 on the plate 48 which will correspond to a desired channel. A further operation of switch A<SP>1</SP> or D will move shaft 11 until the next screw 53 or 54 on plate 48 opens switch C. A control knob 12 on the shaft 11 allows of manual operation of the tuning device when the motor is not energized since the gear 39 is then uncoupled. A fine-tuning knob 13 is also provided. As an alternative to the control plate 48 one of the discs 63 inside the tuning device 31 may be employed to actuate a switch E corresponding to the switch C.