Patent GB-443600-A (GB)
Title: Improvements in or relating to change speed gearing
IPC: G07F15/08
Filed: 1934-09-17
Abstract: 443,600. Change-speed gearing; prepayment mechanism for meters. ELECTRICAL APPARATUS CO., Ltd., BARBOUR, R. H., and NOBLE, H. F., Vauxhall Works, South Lambeth Road, London. Sept. 17, 1934, No. 26642. [Class 80 (ii)] [See also Group XVIII] Comprises two-speed gearing in which the speed ratio is changed between a driving- shaft 119, Fig. 5, and a countershaft 115 by the continuous turning of an arbor 113 through two right angles. This turning of the arbor 113 first rocks the shaft 115 away from the shaft 119, as shown in Fig. 3, so as to separate gears such as 117, 118, Fig. 5, which are in mesh, then slides the countershaft 115 axially so as to bring a gear 125 of another pair opposite its mating gear 126, and then rocks the countershaft 115 back so as to move the gear 125 in its own plane into mesh with the gear 126. This two-speed gear is specially adapted for changing the scale of a coin-freed prepayment electricity meter described in Specification 443,599, [Group XVIII]. To change the scale of the meter, an authorized person after removing a seal, 130, Fig. 1, (not shown), turns by a screwdriver the arbor 113, Fig. 2, round so as to bring the letter B on a dial 112 to the position shown of the letter A, without intermediate settings. The motor of the meter through a wheel 111, Fig. 5, drives the shaft 119; the countershaft 115, Fig. 4, through a long pinion 116 constantly drives a wheel 110 on a hollow shaft 210 which carries one side gear of a differential 91. The other side gear being held fast at 90, the meter motor drives a planet-carrying shaft 92 of the differential 91 which causes a trip nut 98 on a screw 97 to approach a cutting-out switch, not shown. The coin-freed mechanism acts to turn the gear 90 so as to reverse the shaft 92 and screw 97 and draw the trip nut 98 away from the cut-out. The countershaft 115 is supported in a bracket 114, Fig. 3, adapted to rock about the common axis of the shafts 210, 92. In changing speed from the high-speed setting " A " shown in Fig. 5, a first cam 122 carried by the arbor 113 as it turns to the left of Fig. 3 pushes back a pin 123 on the bracket 114 so as to rock that bracket against the tension of a spring 215 so that the shaft 115 is carried bodily away from the shaft 119. The gears 117, 118 are thus separated but the shaft 115 is prevented from free rotation by a fixed tooth 129, Figs. 3 and 5, engaged by the gear 125. On continued turning of the arbor, a second and helical cam 121, Fig. 4, carried by the arbor engages a stud 124 fixed to the bracket 114 so that the bracket is slid along the shaft 92 against the tension of the same spring 215, carrying the countershaft 115 axially. The shaft 115 slides remaining in mesh at 116, Fig. 4, with the wheel 110 until the gear 125, Fig. 5, comes into the plane of the gear 126. The cam 122, Fig. 3, then slips under and clear of the pin 123 so that the bracket 114 swings back to the right and the gear 125, Fig. 5, is carried out of mesh with the fixed tooth 129 and into mesh with the gear 126, which then transmits the drive instead of the gear 118 in the low-speed setting "B." The arbor 113 is turned backwards to change to setting " A." A fixed stop 127, Fig. 3, stops the arbor and disc 112 exactly in both positions " A " and " B."