Patent GB-347092-A (GB)
Title: Improvements in or relating to power transmission mechanism
IPC: F16H61/02
Filed: 1929-10-16
Abstract: 347,092. Brakes. SALERNI, P. M., 23, Carlton House Terrace, London. Oct. 16, 1929, Nos. 31478/29, 34710/29,35706/29,38842/29, 9858/30, and 24284/30. [Class 103 (i).] Reverse movement or movement from rest, preventing ; applied by springs.-In an epicyclic variablespeed gear for motor vehicles &c., the planet-carrier or cage and internally-toothed a n n u l u s are adapted to be arrested preferably by bidirectional positive detents provided with baulking-means to prevent engagement except when the parts are substantially stationary, but similar devices may be applied to frictional brakes therefor. A sliding dog - clutch and the arresting-means are operated by a single lever having angular movements in two planes. The four-speed and reverse gear shown comprises a sun-wheel 4, Fig. 1, on the driving-shaft 2, an annular driven sun-wheel 7, and preferably three compound planet pinions 5, 6 carried by the endplates 8, 9 of a cage 10, the larger planets 5 meshing with teeth 15 on a revoluble annulus 12, 13. A dogclutch sleeve 25, splined on the driven shaft 3, is slidable to engage internal dogs on the parts 2, 7, 9, 13, and, as shown, the parts 8, 12 have peripheral dogs 8a, 12a engageable by positive detents, baulking-means being provided to prevent engagement of the dogs 8a, 12a except when they are substantially stationary. The sleeve 25 and locking-detents are shifted by a lever 26, Figs. 3 and 4, mounted on a ball-joint 27 so as to move angularly in perpendicular planes, its fork 28 being pivoted to a slotted yoke 29 so engaging collars 25b on the sleeve as to allow lateral movements of the lever without affecting the sleeve, while the detentmechanism is actuated by an arm 31 mounted on a rockshaft 32 and so engaged by a fork 30 on the yoke 29 as to be unaffected by longitudinal movements of the lever. The shaft 32 carries staggered cams 33, 34 engaging respectively rollers 35, 45 connecting the adjacent ends of similar pairs of bell-crank detent-carrying levers 36, 46 pivoted at 37, 47. The levers 36 are pressed into action by springs 40 and carry pivoted pawls 38, Fig. 4a, which are cushioned by spring-plungers 39a bearing on curved surfaces on the lever; 36 and coact at diametrically opposite points with the annulus teeth 12a. The levers 46 &c. for the cage teeth 8a are identical. In the mid-position of the arm 31, Fig. 4, both pairs of detents are out of action; movement to the left allows roller 35 to roll down cam 33 and release detents 36 &c. ; movement to the right allows roller 45 to roll down cam 34 and release detents 46 &c. The actual engagement of the detents is however permitted only when the dogs 12a, 8a, having slowed down and come to rest, tend to run reversely. Thus, a baulking-ring 41 loosely surrounds a conical boss on a web 1a, Fig. 3, of the casing 1 and, by gravity, presses with light friction against the end-plate 13. A nose 44 on each lever 36 engages, according to the direction of rotation, one of a pair of seatings 43 on the ring 41 having a slope of about 6‹, until, when rotation starts to reverse, the ring 41 is dragged round, allowing the noses 44 to be thrust by the springs 40 into notches 42 and the pawls 38 to engage the dogs 12a. Similar baulking means, including a ring 51 coacting with the end-plate 8, are provided for the levers 46. The lever 26 moves in a gate 60, Figs. 3, 4 and 13, and is provided with a catch 55, operable by a pivoted knob 57, arm 58, and flange 56, for the purpose, inter alia, of limiting its movement in the lateral slots 62 .. 65. When, however, the catch 55 is raised, the lever can make extended lateral movements which bring pairs of lugs 33a, 34a on the cams 33, 34 into engagement with pairs of lugs 41a, 51a on the baulking-rings, in order to release the detents for engagement at will in emergency. The baulking-devices are bidirectional so that, if the synchronous condition is "overshot," manipulation of the enginespeed is necessary to engage the detents. Fig. 29 shows the modification in which spring-pressed friction brake shoes 86, with or without resilient shock-absorbing means, are mounted on pivoted arms 84 operated by short arms 82 on the levers 36, and are provided with similar baulking-means 41 .. 44. The baulking-rings 41, 51 for the positive or frictional locking-means may be replaced by spring-pressed shoes engaging the periphery or other part of the annulus or cage and provided with inclined faces &c. to prevent locking except when the parts are substantially at rest. The second Provisional Specification states that the baulking-means for the detents may comprise a roller. The third Provisional Specification describes detent-mechanism having a rocking lever with a dog or pawl at one end for locking the annulus and a dog or pawl at the other end for locking the planet carrier, the lever being biased by a preset spring plunger coacting with inclined surfaces. It describes also cam or link connections whereby movement of the operating lever into the " reverse " position displaces a baulking-roller in its slot to free the pawl for engaging the annulus. The fourth Provisional Specification states that the detents are withdrawable alternatively by toggle-mechanism. The fifth Provisional Specification describes laminated-spring shock-absorbing means for the detents. Specifications 347,093 and 347,165 are referred to in the second and third Provisional Specifications.