Patent GB-725088-A (GB)
Title: Improvements relating to intermittent mechanical motions
Inventor: WILDHABER ERNEST
IPC: F16H27/04
Filed: 1953-07-31
Abstract: 725,088. Intermittent toothed gearing. GLEASON WORKS. July 31, 1953, No. 21310/53. Class 80 (1). In a mechanism wherein a mutilated gear 29 on a driving shaft 20 intermittently drives a gear 31 on a driven shaft 21, two rollercarrying pins 23, 24, on a member 22 on the shaft 20 co-operate with two non- radial slots 26, 27 which are open at both ends and are formed in a member 28 on the shaft 21, the parts being so arranged that when the gearing 29, 31 is operative the pin-rod-slot mechanism is out of action but as the gear 29 reaches its mutilated portion and so ceases to drive the pin 24 engages the inner end of slot 27 and, passing along the slot, smoothly retards the shaft 21 to a momentary standstill, whereafter the pin 23 passes along the slot 26 to accelerate the shaft 21 to a uniform velocity as the gear 29 takes up the drive again. Fig. 1 shows the mechanism at the moment when the gear 29 is taking up the drive and the pin 23 is leaving the slot 26. The pins are equidistant from the axis of shaft 20, while the straight slots 26, 27 are parallel and symmetrical about a radius of shaft 21. In a modification for use in an inking mechanism wherein an operating cycle comprises fifteen revolutions of a driving shaft 41, a driven shaft 42 has a stationary period extending over twelve and one half turns of the shaft 41, and is driven through three turns during the remaining two and a half turns. The shaft 41 has thereon a gear 49 and a disc carrying a single pin and roller 44. The driven shaft 42 has independently slidable thereon a gear 51 one end of which is mutilated, and a member 48 having two parallel slots 46, 47 which are similar to those of the member 28 and which, when the member is moved to the left, co-operate with the pin 44. The member 48 and gear 51 are moved axially by levers actuated by cam tracks 59, 61 formed on a drum driven, through worm and bevel gearing, from the shaft 41, the reduction ratio being one to fifteen. During each revolution of the cam drum the member 48 is moved twice into the path of the pin 44 and returned twice, while between these movements the gear 51 is moved once to bring the unmutilated end into engagement with the driving gear 49 and is returned as the member 48 is moved for the second time. The sequence of events, starting just before the end of the long dwell period of the driven shaft (during which period the gear 49 has-been in line with the mutilated end of the gear 51) is: (1) Member 43 is moved to engage the pin-and-slot mechanism; (2) pin 44 passes through the slot 46 to accelerate the shaft 42 to its uniform velocity; (3) as pin 44 leaves the slot the first tooth of the mutilated end 51 is engaged; (4) gear 51 and the member 48 are both moved to the right so that the unmutilated end of gear 51 takes over the drive and shaft 42 is rotated slightly more than two turns without interference from the pin-and-slot mechanism; (5) gear 51 and member 48 are moved to the left to engage the mutilated end of the gear and to enable the pin 44 to pass through the slot 47 to bring the shaft 42 smoothly to rest after the last tooth of the mutilated end has been reached; (6) the member 48 is moved to disengage the pin-and-slot mechanism so that the shaft 42 remains stationary till the end of the cycle: A modification is described wherein the straight slots are replaced by slots of circular arc form.