Patent GB-370915-A (GB)
Title: Improvements in and relating to hydraulic transmission mechanism
IPC: F16H39/08
Filed: 1930-10-06
Abstract: 370,915. Hydraulic transmission of power. BEDFORD, J., Lucerne, Old Bedford Road, and PARK, M. C., 54, Havelock Road, both in Luton. Oct. 6, 1930, No. 29891. [Class 69 (ii).] In hydraulic transmission mechanism of the kind employing a pump and motor each of variable capacity arranged so that the capacity of the pump increases as that of the motor diminishes, the pump and motor cylinders are carried by the driven shaft and the means for reciprocating the pump and motor pistons are carried by the driving shaft and a stationary member respectively. The mechanism is provided with means for obtaining a reverse drive, comprising in one form means for temporarily clutching the cylinders to a stationary member, and for clutching the motor piston actuating mechanism to the driven shaft. In the arrangement shown in Fig. 1, the cylinder block 4 is carried by the driven shaft 2, the pistons 7a, 7b of the pump and motor being operated by rings 9a, 10a, and 9b, 10b. The rings 9a, 10a are carried by a member secured to the driving shaft 1, and their eccentricity is adjusted by levers 18 connected to a slidable collar 23. The rings 9a, 10b are carried by the fixed casing 3, and their eccentricity is adjusted by crank pins on spindles 30, the adjusting means for the two sets of rings being connected by levers 32, links 33 and levers 34. The pump cylinders communicate with suction and delivery chambers 38, 39 through non-return valves 36, 37, and communication between these chambers and the motor cylinders is controlled by a rotary valve 43 driven through epicyclic gearing from and at half the speed of the driven shaft. Means are provided for changing the timing of the valve when a reverse drive is required. In the form shown in Fig. 7, the eccentricity of the pump rings 9a, 10a is adjusted by slidable cam members 62, 63, and that of the motor rings by eccentrics 66 on spindles 65, the adjusting means being interconnected. The distributing valve comprises portions 43a, 43b, carried by the driving shaft and a normally stationary member 84 respectively ; the member 84 may be adjusted by a quadrant 86 to obtain a reverse drive. In another form, the rings are adjusted by pins 96, Fig. 15, engaging worm wheel teeth or cam slots in the rings and operated from a sleeve 90, 91. Each motor cylinder has a distributing valve 43 oscillated by tappets 110 from eccentrics 108, 109, the travel of these valves being gradually reduced to zero as the eccentricity of the motor rings 9b, 10b is reduced to zero ; this is effected by adjusting the eccentrics 108, 109 by means connected to the operating means for the sleeve 90, 91, said means being such as to permit alteration of timing to obtain a reverse drive. In another form, the pistons 7a, 8a of inner cylinders are actuated from discs 124, Fig. 19, the eccentricity of which is adjusted from a slidable member 138 ; the member 138 carries cams 150 for adjusting the eccentricity of members 144 carrying discs 139, 140 which operate outer pistons 7b, 8b. Suction and delivery chambers 38, 39, and a valve 43 are disposed. between the inner and outer cylinders..The form shown in Fig. 21 .has a swash-plate pump and motor, each comprising a pair of tilting plates, the pump plates 154a, 155a being adjusted by a slidable cam member 157, and the motor plates by cams 169 on a sleeve 170, the means for operating the cam 157 being connected to the means for turning the sleeve 170. In another form, the pump pistons 7a are operated from tilting plates 154a, 155a, Fig. 20, the plate 154a being adjusted by pins 180 slidable in inclined slots 179 in the plate and axial slots 181 in the driving shaft, and the plate 155a by pins 182 engaging recesses. 183. The motor plates are similarly adjusted, and the adjusting mechanisms are connected. Distributing valves 43 are operated by tilting discs 198a, 199a, 198b, 199b, pivotally mounted on the shaft 1 and a sleeve shaft 191, and adjusted by cam projections on the tilting plates 155a, 155b. The cylinder block 4 is carried by a sleeve'shaft 196, which during forward drive is coupled to the driven shaft 2, the sleeve shaft 191 and motor tilting plates being held stationary ; for reverse drive, the shaft 191 is coupled to the shaft 2, and the shaft 196 held stationary.