Patent GB-1233338-A (GB)
IPC: G06G3/08
Filed: 1969-09-29
Abstract: 1,233,338. Inegrating-apparatus. TEST S.A. D'ETUDES TECHNIQUES. Sept.29, 1969 [Oct.2, 1968], No.47776/69. Heading G1J. [Also in Division F2] In a digital integrator (or step-by-step variable ratio gearing) comprising a table 1 mounted for rotation and a toothed wheel 20 rotatably mounted for engagement with a toothed surface of the table 1 and for displacement radially of the axis of rotation of the table, (a) the surface of the table has concentric toothed tracks C1, C2, C3, C4, Fig. 5, of different radii (D, 2D, 3D, 4D) and at least two toothed transfer tracks (twelve descending and twelve ascending archemedian spirals Sd1 to Sd12 and Sm1 to Sm12 of pitch 12D, the transfer tracks inter-connecting the circular tracks therby permitting passage of the wheel 20 therebetween, and (b) the teeth of all the tracks are so arranged that rotation of the wheel 20 on the tracks remains constantly proportional to the distance of the wheel 20 from the axis of rotation of the table both on the circular and transfer tracks. The table 1 is rotated through an input shaft 6 and any drive transmitted to the wheel 20 causes rotation of a shaft 14 in a direction and with a transmission ratio dependent on the radial displacement of the wheel 20 to one side or the other of the centre of the table 1. This displacement of the wheel 20 is controlled by the selective energization of neither or one or other of two coils 30, 31 of an electromagnet 28 to determine in every twelfth revolution of the table 1 whether the wheel 20 remains on the same circular track or moves along an ascending or descending transfer track into the adjacent outer or inner circular track to change the transmission ratio between the input and output shafts 6, 14. The wheel 20 and an auxiliary wheel 21 are contained in casings 17, 18 (inter-connected to form a slide) by a plate 19 with seven arcuate grooves 22a to g spaced in correspondence with the spacing of the circular tracks C1 to C4. The gear-ratio changing mechanism includes a ring 7 housed in the table 1 to form pivots for twelve fingers 8 equally spaced circumferentially, each with a lower end 10 guided in a groove 24 in a base place 11. As each finger 8 is carried past the electromagnet 28 the selected state of the coils 30, 31 determines: - (a) whether the finger 8 remains vertical or is rocked by an upper or lower magnetic pole. (b) which portion 24a, b or c of the groove 24 the lower end 10 will follow. (c) which of three adjacent grooves 22a to g in plate 19 the upper end 23 will enter when the finger reaches the radius 126. When a finger 8 has been rocked, its return to the vertical causes the upper end 23, to move the slide a distance D toward or away from the centre of the table 1. The wheel 20 has twenty four pointed teeth and the table 1 has recesses of the same circumferential pitch on the circular and transfer tracks. As a plurality of teeth of the wheel 20 simultaneously engage teeth of the table, clearance recesses are provided radially linked into continuous groups as necessary to provide clearance during transfer without losing positive drive. A cam 37 Figs.2, 6, 7 (not shown) is provided for co-operation with the upper side of the auxiliary wheel 21 which has twelve teeth, the cam being arranged to control transfer across the centre of the table within the circle C1 Other embodiments Figs.8 to 10 (not shown) employing differential gears are designed to avoid passage to the centre of the table.