GB403134A - Improvements in ratchet and pawl mechanism such as for deriving rotary motion from reciprocating motion - Google Patents

Abstract

403,134. Ratchet gearing ; toothed gearing ; coin-freed apparatus. WHITESMITH, I. N., 20, Queens Road, Urmston, Manchester, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. June 27, 1932, No. 18100. [Classes 80 (i) and 80 (iii).] A ratchet and pawl device is combined with a second one, both being driven by the same element, the driven member of the second being arranged to drive a toothed wheel through a gear train by which a one-tooth movement of the second becomes a movement of the driven member which is a fraction of such movement produced by a movement of the driver of the first ratchet spatially equal to a movement of one tooth of the second ratchet. The device is especially applicable to prepayment electricity meters. On the insertion of a coin, a shaft 2 is connected to a handle 3, which is thereupon given a half-turn. This is taken up by a lever 4 fast on the shaft and carrying fingers 5. When one of these meets a pin 6 on a loose arm 7 carrying a pawl 13, a sun wheel 9 is turned until the arm meets a stop 15 on a frame 11 carrying reduction gears 12, which transmit the motion of the wheel 9 to a wheel 10. This carries a pawl 22 in mesh with a wheel 23 which is connected through a wheel 24 with a " commodity " wheel 1. When the arm 7 meets the stop 15 the frame 11 and the wheel 9 are carried round together until a projection 17 meets an adjustable stop 16. The finger 5 thereupon slips past the pin 6 to complete the half-turn of the lever 4 while a spring 18 pulls back the frame and the wheels 9, 10 until the projection 17 meets a fixed stop 20, and the arm 7 falls back against an adjustable stop 21. The pawl 22 meanwhile returns idly over the wheel 23, the angular movement being determined by the separation of the stops 20, 16. Oscillation of the lever 7 alone thus causes fractional tooth movements of the wheel 23, and whole tooth movements when it carries the frame 11 with it. In a modified construction, Fig. 2, the frame 11 is connected with the wheel 23 by a sleeve 23a loose on the shaft 2, on which are mounted arms 27, 28 carrying pawls 29, 30 for engagement with wheels 31, 32 connected respectively with the wheels 9, 10. Loose on the shaft are two toothed wheels 36, 37 having adjustable shrouds 38, 39, and connected to dials and adjusting heads. The motion given to the wheels 9, 10 by the shaft 2 depends on the angular distance between the point at which the pawl leaves its shroud and the point at which the movement of the pawls is stopped by a fixed stop 35.