Patent GB-333694-A (GB)
Title: Improvements in clutches for motor cars and other machines
IPC: F16D41/08
Filed: 1929-06-28
Abstract: 333,694. Vondra, K. June 28, 1929. Clutches, ratchet; variable-speed toothed gearing; operating or controlling cutches.-In oneway clutches for motor vehicles &c., there is provided a catch normally preventing engagement but movable by its own centrifugal force to permit engagement. The invention is applicable also to two-way clutches convertible into one-way clutches. Manual control-means may additionally be employed. The clutches may be used in planetwheel gearing and in constant-mesh variablespeed gearing, means being provided for preventing release of the catches while the driving-members rotate faster than the driven shaft, the appropriate gear being automatically engaged when the driving shaft is retarded, as by declutching the engine. A gear-wheel 2, Fig. 1, loose on the driven shaft 1, is adapted to be clutched thereto by frictional engagement with a loose male or female cone 3, which has single or double acting inclined-tooth engagement 23 with a member 4 fast on the shaft 1. A spring- pressed drag-ring 11 tends to rotate the parts 3, 4 relatively, and, by the action of the teeth 23, bring the clutch members 2, 3 into engagement. Unless, however, a centrifugal catch 7, pivoted at 8 on the cone 3, has moved out against its spring 12, a nose 9<1> on the catch prevents the parts 3, 4 from separating sufficiently to cause the engagement, the nose 9<1> then entering a recess 9, which prevents it from flying out until, when the driving-member 2 is decelerated, the members 3, 4 approach and a spring 10 thrusts the nose out of the recess. If the spring acting on the ring 11 is sufficiently strong, the spring 10 may be omitted. Antifriction balls may be provided between the teeth 23. Fig. 2 shows a modified catch 7. pivoted at 13 on the part 4 and coacting with a notched lug 16 extending from the cone 3 (not shown) to prevent relative rotation of the inclined teeth in one direction. The movements of the catch are limited by the shaft 1 and a stop 15. The ring 11 may be replaced by springs between the parts 3, 4 acting to press the parts 2, 3 into light engagement. In another form, Fig. 3 (not shown), the catch coacting with the lug 16 slides on a radial bar extending from the shaft 1 and is spring-pressed inwards. In using the clutch between coaxial shafts, the driving-member has a flange fitting behind the part 4 to take axial thrust due to the teeth 23. The cone clutch may be replaced by a multiplate or dog clutch. Where the inclined teeth act bidirectionally, means are provided for rendering the clutch unidirectional at will. Fig. 8 shows a bidirectional form of teeth 23 with interposed balls 27 suitable for use with dog clutches, the parallel sides of the teeth ultimately transmitting drive beween the parts 3, 4 without axial thrust when the clutch is engaged. In a unidirectional modification, Figs. 9 and 11 (not shown), the pitch of the parts engaging the balls increases up to infinity in the position where the dog clutch is engaged. In another construction, the cage 24, Fig. 14, of a roller clutch between the wheel 2 and a member 22 on the shaft 1 is provided with the lug 16 for engagement with a radiallysliding centrifugal catch 7 or with a pivoted catch as shown in Fig. 2. Either the wheel 2 or part 22 may have inclined seats for the rollers 20, the cage having slight friction with the smooth element. As shown in Fig. 15, the wheel 2 is pressed by opposed sets of balls 20 acted on by single or double acting toothed members 18, 19 fast on the shaft 1, the cages 24, provided with the lugs 16, being slightly spring-pressed against the wheel. In all the forms described, the notches in the lugs 16 &c. may be omitted, so that the catches 7 may release without retardation of the driving-part. The constant-mesh gear-box shown in Fig. 20 comprises a wheel 2c fast on the engine clutch shaft 1a, which rotates as shown by the arrow, and wheels 2, 2a, 2b loose on the driven shaft 1, the wheels being associated respectively with clutches 31<c>, 31, 31<a>, 31b on the shaft 1 and meshing with clutches 31<c>, 35, 35a, 35b on the layshaft 36. The wheel 2, together with its clutch 31, is shiftable to engage reversing-pinions 37, 37a by a fork 32 and spring-return rod 33. - The clutches may be of the kind shown in Fig. 14, clutches 31, 31<c> being, however, bidirectional and the centrifugal catch being omitted from clutch 31. The springs of the centrifugal catches (not shown) are adjusted to allow release at speeds appropriate to the respective gear-ratios. Manually-actuated stops 7<1>, 7a, b, c on collars 43, 44 coact with lugs 16, 16<a>, b, c on the clutch cages, the collars being shifted to set the stops in the various positions shown in Figs. 21-24 by a spring-pressed rod 41, controllable either by a connection 54 to the main clutch pedal or by a hand-lever 45 having a spring latch 48 engaging a notched quadrant 50. In the first or righthand position of the stops, the direct-drive clutch 31<c> is left free for bidirectional drive, clutch 31 is locked out for both directions, and the other clutches overrun. The second position, where clutch 31 is still locked and clutch 31<c> is rendered unidirectional, is used for starting and frequent gear-changing. To start from rest, the clutch pedal is depressed thus shifting the stops 7<1> &c. into the spaces between the second and third positions and applying a brake to the shaft 1<a>. The cage of clutch 31 is then carried round into the forward-drive position, stop 7<1> being relatively in the position shown in dotted lines so that it cannot return when the pedal is released. All the centrifugal catches are latched in their inmost positions. To change gear, the accelerator pedal is suddenly released, and, when wheel 2<a> turns more slowly than shaft 1, its centrifugal catch is unlatched and clutch 31a engages. The drag on the cage of clutch 31 then turns it to neutral and allows the spring 42 to return stops 7<1> &c. to the second position. As the car speed rises, the other clutches can be similarly engaged in succession, coasting being possible on any gear. The car may be brought to rest without declutching by decelerating shaft 1<a> until all the centri. fugal catches are retracted and subsequently become latched. The clutch pedal need only be depressed when changing from second to bottom gear. If, after decelerating and declutching the engine, the stops 7' &c. are moved by lever 45 into the third position, clutches 31<a>, b, c become ineffective and clutch 31 becomes bidirectional, allowing the engine to be used for braking when the main clutch is re-engaged. On moving lever 45 forward, it contacts with a pin 47 on the rod 33 to put in reverse gear, the lug 16 being simultaneously withdrawn from the stop 7<1> to render the clutch 31 bidirectional. The remaining clutches are locked by the centrifugal catches.