Patent GB-955002-A (GB)
Title: Improvements in power transmission and brake mechanisms
IPC: F16D49/08
Filed: 1961-05-08
Abstract: 955,002. Reverse gear and control; band brakes. TRANUCO PROPRIETARY Ltd. May 8, 1961 [May 17, 1960], No. 16670/61. Headings F2D, F2E and F2L. Planatary gearing comprising a reaction brake and an output shaft brake includes a reaction band brake on a floating lever movable along fixed guide tracks and turned by a control cam to engage and disengage the reaction brake, of which the engagement is self-energized, control mechanism operating the reaction and output shaft brakes so that when one is engaged the other is disengaged, and vice versa. Gearing.-A forward-reverse planetary gear for motor cars, winches &c. comprises an input shaft 20, Fig. 1, fast with a double sun gear 60, 61. The sun gear 60 meshes planet pinions 68 on a carrier 52 fast with an output shaft 21, the planets also meshing a ring gear 69 stationed by a brake band 102 to establish forward drive. The sun gear 61 meshes planets 73 in a carrier 77 stationed by engagement of a brake band 104 to establish reverse, the planets 73 also meshing a ring gear 44 fast with the output carrier &c. 52. A brake band 103 is engaged with the ring gear 74 to station the output shaft 21. Forward brake; reverse brake.-The brake bands 102, 104 are engaged with their respective drums by two mechanisms which are similar but arranged in mirror-image fashion. The forward drive brake band 102, Fig. 3, is connected at its ends by pins 125, 126 to a floating double lever 124 guided by rollers 129 for movement along arcuate fixed tracks 131 in a surrounding housing 86. A cam 110 is fast with a control shaft 90 (see also Fig. 4), and is turned to engage rollers 143 carried by the cam with the upper surface of the double lever 124, itself thereby turned about the pin 126, which journals the rollers 129. The brake band 102 is accordingly tightened upon the ring gear 69, which rotates clockwise, and carries the floating lever 124 with it to the Fig. 7 position. The floating lever 124 runs along its arcuate guide tracks 131 against the bias of an anchor spring 137 and the bias of a link spring 141 connected to a lever 116 journalled about a shaft 91. The reaction of the link spring 141 tends to turn the floating lever 124 yet further in the brake-engaging direction. As the control cam 110 continues to turn, a roller 144 at its end engages the lever 116 and turns the latter to tension the link spring 141 and increase the brake-engaging force. If the gear is overloaded, the floating lever 24 is carried beyond the Fig. 7 position to contact a stop 146, by which it is turned to release the brake and allow slipping. Output shaft brake.-The output shaft brake band 103, Figs. 4, 10, is pivoted on two levers 149, 150 having forked lower ends 154, 156 straddling parallel beams 159, 160 on which they are pivoted by a pin 157. A spring 163 adjustable to take up wear &c. biases the pin &c. 157 upwardly to engage the brake 103. If the ring gear 106 is rotating when the brake is engaged, the assembly of levers 151 &c. follows an arcuate track 174 along which it is guided by rollers 169, 170. The upper end of one or other of the levers 149, 150 then engages a stop 179, 180, respectively, to turn the lever about the pivot-pin 157 for self-servo engagement of the brake band 103. Disengagement of the brake is effected by pairs of cams 111, 117 on the shafts 90, 91, Fig. 4, being turned to the positions shown in Figs. 8, 10, when they engage the lateral beam 159 and force it downwardly against the bias of the engaging spring 163. Control.-A single start-stop, forward-reverse control lever 92, Fig. 1, is provided with a toothed segment 95, Fig. 2, for engagement with toothed segments 93, 94 fast on the control shafts 90, 91. A detent leaf spring 97 engages the teeth of the segments 93, 94 to retain the shafts 90, 91 in a required position. The cam 110, Fig. 9, effecting engagement of the forward drive brake band 102, is fast on the shaft 90 and is fast with the first cam 111 effecting disengagement of the output shaft brake 103. The lever 116, co-operating with the cam 110, is journalled on the control shaft 91 and is fast with the second cam 117 effecting disengagement of the output shaft brake 103. The arrangement is such that as the cam 110 and the lever 116 turn to engage the forward drive brake band 102, the cams 111, 117 are simultaneously turned to release the output shaft brake 103, thus preventing shocks. When the control lever 92 is restored to its neutral position, the forward drive brake 102 is released, and the output shaft brake 103 is reapplied. A similar arrangement of cams, levers &c. 114, 120 engage the reverse band brake 104 &c. when the control lever 92 is turned in the opposite direction from its neutral position.