Patent GB-333222-A (GB)
Title: Improvements in or relating to power transmission mechanism
IPC: F16D23/02
Filed: 1929-02-07
Abstract: 333,222. Salerni, P. M. Feb. 7, 1929. Facilitating changing speed ; clutches. - Relates to bidirectional dog clutches of the kind which employ a baulking-ring or member to prevent engagement except when the shaft speeds are equal and which may be employed, as described in Specification 306,636, between the gear-box and the back axle of an automobile, so as to permit coasting and facilitate speed-changing. The clutch may be operated by a spring or by a lever, which may be the foot lever controlling the main engine clutch, and the baulking-ring, which engages one of the clutch members, preferably the driving-member, by a white metal, bronze, &c. antifriction surface or washer, may be rotated to permit clutch engagement at any time, an auxiliary cone or plate clutch being engaged in the same operation to equalize the shaft-speeds. The clutch-member A<1> splined upon the driving- shaft A carries teeth A<2> for engagement with teeth B<2> on the driven member B<1>. The baulking- ring C engages by antifriction means D the member A<1> and has teeth C<3>, partly inclined at an angle of approximately 6‹, engaging similar projections B<3> on the member B<1>, and plain teeth C<5> which engage notched teeth B<5> on the member B<1>, when, as shown in Fig. 1. the clutch teeth A<2>, B<2> have been disengaged and the driven shaft is overrunning the driving-shaft. The slope of the inclines on the teeth C<3> is insufficient to enable the axial pressure exerted upon the member A<1> to effect rotation of the ring, and is such that the resistance to their movement relatively to the projections B<3> is less than that of the ring relatively to the member A', so that when the member A<1> overtakes the member B' the ring moves over the member A' and the clutch A<2>, B<2> is automatically engaged by the spring means &c. In the modified construction shown in Figs. 24 and 25, the driving-shaft A carries a sliding clutch member A<1> engageable with the driven member B', as before, but the baulking-ring is formed in three parts, C, C', C<2> interconnected for common rotation by pins C<5> secured in the part C<2>, and the projections B<5> on the member B' have additional inclined faces B<5>x for engagement by the pins C<5> when effecting clutch re-engagement before the shafts synchronize naturally. The part C<2> engages an antifrictional washer D on a sleeve A<3> splined to the member A' and is spaced by springs C<6> from the ring part C', additional springs (not shown) spacing the part C<2> from the presser-plate E' of a multiplate clutch E interconnecting the pins C<5>, and thus the whole baulking-ring, with a sleeve A<4> splined to the member A'. A loose ring F is arranged between the washer D and a series of brake-plates G splined on the member A', and the ring F is trunnioned to a bell-crank operating-lever H, H<1> on a rock shaft I, a cross pin J<3> in which pivotally supports a cam J with projections J<1>, J<2>, adapted for engagement respectively with lugs K<1>, K<2> on a lever K which carries a toothed segment L<1> engaged by a similar segment on a shaft M which is linked to move with the main engine clutch pedal. A lever N moving with some lost motion relatively to the lever K is secured to one end of a torsion spring (not shown) of which the other end is secured to the shaft L to which the lever K is keyed. A spring plunger J<4> parallel with the shaft I slides in the casing and, as the shaft rotates, swings the cam J about its pivot pin J<3> to move the projections J<1>, J<2> alternatively into the paths of the lugs K<1>, R<2>. When the clutch A<2> B' is engaged, full depression of the main clutch pedal turns the shafts M, L so that the lug K<1> engages the projection J<1> and turns the arm H farther to the right than the position shown so as to press the brake-plates G against a stationary member G', so disengaging the clutch and slowing the shaft A' to facilitate speed changing. Release of the main clutch lever then allows return of the parts to the position shown, further movement of the part A<1> being prevented, while the shaft B is overrunning, by the baulking-ring. During the return of the lever K, the arm N moves freely therewith until it strikes the temporarily stationary lever H<1> on the shaft I. when its lost motion connection with the lever K permits it to stop so that the torsion spring exerts a force opposing that of the main engine clutch spring, partial engagement only of the main clutch to speed up the shaft A thus being possible. Meanwhile the pressure of the torsion spring, but not of the main clutch spring, owing to the main clutch parts being in engagement, is exerted upon the arm H<1> so as to cause engagement of the clutch A<2>, B<2> when the shaft speeds synchronize. This action takes place without compression of the springs C<6> ; further, it removes the opposing effect of the torsion spring, so allowing the main clutch to engage fully, and it allows the arm N to move downwards to a position in which it prevents return movement of the lever H' to disengage the clutch A<2>, B<2>. If it is desired to engage the clutch A<2>, B<2> before the shaft A synchronizes with the shaft B, as when the engine is stalled upon a down slope. the engine clutch pedal is again depressed, and as the projection J<2> is. due to the plunger J<4>, in the path of the lug K<2>, the shaft I is turned in the opposite direction, so that the baulking-ring part C<2> is moved against the springs C<6> to cause the heads of the pins C<5> to engage the faces B<5>x of the projections B<5> and turn the baulking-ring. to permit engagement of the clutch A<2>, B<2>, under pressure of the foot. At the same time the pressure plate E<1> is moved, by pressure of the part C<2> against the additional springs referred to, to engage the clutch E to connect the member A<1> to the baulking-ring, and thus frictionally to the rapidly moving driven member B, so that the member A<1> is brought to approximate synchronism with the member B<1>. When the abutment of the part C upon the member B<1> is thus released, the part C advances upon the pins C<5> to release the clutch E and free the rinz from the member A<1>. Specifications 333,234 and 334,503 are referred to. According to the first Provisional Specification, rolling contact may be employed between the baulking-ring and the driving clutch member, and the inclined faces on the ring and driven clutch member may be helically formed to facilitate their relative movement.