GB868689A - Improvements in or relating to multi-speed driving arrangements - Google Patents

Abstract

868,689. Reverse gear. ELECTRIC & MUSICAL INDUSTRIES Ltd. July 23, 1959 [July 29, 1958], No. 24472/58. Class 80 (2). A gear for driving the capstan roller of magnetic tape transducing apparatus comprises a driving shaft formed with wheels or surfaces of different diameters and carrying frictionally a plate upon which are mounted two idlers, alternatively engageable with driven surfaces on an output member according to the direction of rotation of the driving shaft, to rotate the output member always in the same direction but at different speeds. In one form, a friction wheel 4, Fig. 1, is fast upon a driving shaft 3 which carries by means of a light friction coupling a mounting plate 5 upon which pivot arms 8, 9 carrying idlers 6, 7 at their ends. Rotation of the shaft 3 and the wheel 4 in an anticlockwise direction acts through the light friction coupling to rotate the mounting plate 5 in an anticlockwise direction so that the idler 6 engages between the wheel 4 and a hub 2 of a driven flywheel 1, which accordingly also rotates in an anticlockwise direction. If the shaft 3 and the wheel 4 are instead rotated in a clockwise direction, the light friction coupling turns the plate 5 clockwise to disengage the idler 6 from the hub 2 of the flywheel and instead engages the idler 7 directly with the shaft 3 and also with the-inner periphery of the flywheel 1, which again rotates in the anticlockwise direction but at a much slower speed. The idler wheels 6, 7 may be provided with rubber on their engaging surfaces. In a modification, the driving shaft 3, Fig. 3, carries a drum 15 engaged by a.band 14 connected at its ends by two tension springs 12, 13 to a link 10 pivoting on a pin 11 and carrying upon the arms 8, 9 the two idlers 6, 7. When the driving shaft 3 rotates anticlockwise, the friction between the drum 15 and the band 14 acts through the springs 12, 13 to turn the link 10 anticlockwise and accordingly engages the idler 6 with the wheel 4 and the hub 2 of the flywheel 1. As before, when the driving shaft 3 rotates in the clockwise direction, the idler 7 engages directly with the shaft 3 and with the periphery of the flywheel 1. A link 16 connects the ends of the idler supporting arms 8, 9 so that whichever idler is not driving is held positively out of engagement with its co-operating friction surfaces, thus reducing wear of the parts. To obtain more than two speeds, the shaft 3 &c. may be driven by a multi-speed polechanging reversible electric motor.