Patent GB-957782-A (GB)
Title: Variable speed drive
IPC: B67D7/22
Filed: 1960-09-27
Abstract: 957,782. Variable-speed gear; ratchet clutches. GILBERT & BARKER MANUFACTURING CO. Sept. 27, 1960 [Nov. 4, 1959], No. 33121/60. Headings F2C and F2D. [Also in Division G4] To obtain variation in gear ratio between a shaft 20, Fig. 1, in a petrol pump driven by the petrol meter and a shaft 24 driving through gears 53 &c., Fig. 2, to the price registering mechanism so that adjustments can be made to correspond to changes in the price of petrol, the shaft 20, Fig. 2, is fast with a hollow shaft 42 from which project two rods 46, Fig. 5, around which can rotate bevel gears 50a, 50b meshing a bevel gear 52 fast with the shaft 24. A casing comprising two similar sides 54 joined by arms 55 lies outside the bevel gears 50a, 50b and can pivot relatively to the rods 46, rollers 64 on the casing running over a circular track 66 which, as shown, is horizontal but which can be fitted about the axes of trunnions 72, 78 mounted in a frame 30, 34. The two sides 54 of the casing are connected by pins 104 to the inner clutch members 106, Fig. 6, of ratchet clutches having rollers 108 biased by spring-pressed plungers 110 to wedge against races 112 fast with the bevel gears 50a, 50b. So long as the track 66 lies in a plane normal to the axes of the shafts 20, 42, the two ratchet clutches 106 &c. are inactive and a direct drive is imparted from one shaft to the other. If, however, the track 66 is tilted about the trunnions 72, 78, then the casing 54 oscillates as it rotates and the ratchet clutches 106 &c. alternatively engage to transmit forward impulses through the bevel gears 50a, 50b to the output shaft 24. Adjustment of the angle of tilt of the track 66 and hence of the ratio is effected by turning a handle 126 and a worm 96 meshing a segmental worm gear 94 rotatable about the trunnion 78 and connected through a normally inoperative spring lost-motion device 88, 90 to an arm 84 fast with the track 66. To ensure that the gear ratio is adjusted in incremental steps corresponding to units of currency, the handle 126 can be turned only when it is pushed rightwards of Fig. 1 against the bias of a spring 122 so that an indexing pin 114 is withdrawn from one or other of holes 116, Fig. 3, in a plate 118 itself adjustably secured to a support 105, the indexing pin being re-engaged with another hole 116 by the spring 122 after turning the handle. In order that the rotary impulses applied through the bevel gears 50a, 50b to the output shaft 24 are smoothed and the output shaft rotates at a steady speed when the input shaft 20 rotates at a steady speed, an additional cyclic tilting motion is imposed upon the track 66. A cam drum 140 fast with the input shaft has its track engaged by a roller 142 at the end of a lever 144 fast with a shaft 146 also fast with which is a slotted lever 152. A slide block 160 received in the slotted lever 152 is connected through links 164 &c. to the arm 84 fast with the track 66, so that as the input shaft 20 and the cam drum 140 rotate, the links &c. tilt the track, this motion being permitted by virtue of the spring lost-motion device 88, 90 between the arm 84 and the segmental worm gear 94. Also fast on the lever supporting shaft 146 is a lever 180, Fig. 2A, carrying a roller 182 engaging the track in the cam drum 140 and so biased by a spring 186 as to balance the force of the cam roller 142 engaging the cam track and required to overcome the spring lost-motion device 88, 90, this force tending to oppose rotation of the input shaft 20 and imposing undesirable forces on the petrol meter.