Patent GB-190713897-A (GB)
Title: Improvements in Apparatus for Transmitting Motion at Variable Speed.
Inventor: CLARK WILLIAM
Filed: 1907-06-15
Granted: 1908-03-26
Abstract: 13,897. Clark, W., [Waterbury Tool Co.]. June 15. Actuating pumps; pump cylinders; pump stroke, varying; waste liquid, returning.-In apparatus for transmitting power hydraulically two piston and cylinder members are mounted one upon the driven shaft and one upon the driving - shaft. The cylinders, which are arranged in a rotating cylindrical body, discharge into, and are fed from, a central valve-plate. The pistons are operated by swash-plate mechanism, the angle of inclination of the plate being variable. The back pressure tending to produce leakage between the cylindrical cylinder bodies and the valve faces is restricted and neutralized ; a pumping system for replenishing leakage, means whereby the sudden strains due to abrupt changes of speed may be avoided, and means whereby the constancy of volume and velocity of the liquid may be obtained, are provided. Fig. 5 shows a plan of the machine partly in horizontal section, and Fig. 15 is a longitudinal sectional elevation. The apparatus is mounted on a frame or stand 1, to the centre of which the valve-plate 8 is hung on trunnions 27. The centre of this plate is bored to accommodate the ends of the two shafts 14, 15, the outer ends of which are carried in bearings 2. The parts carried by the driving-shaft 15 are exactly similar to the parts carried by the driven shaft 14. The shaft 15 is connected to the socket ring 17 by a universal joint ring 18, shown in Fig. 9, which is driven by the shaft through the pins 37. The ring 17 is bored on one face to receive the ball ends of the piston-rods 42, and on the other face is turned to form a ball-race for the balls 44, which form a bearing betwean the ring 17 and the non-rotating ring 16 carried in the tilting- ring 3. The latter is supported from the frame by trunnions 28, and is operated by the controlling- lever 5 and link 24. By these means the stroke of the pistons 7, and thus the speed of the driven shaft, may be varied. The pump cylinder bodies 6 are mounted on, and driven by, the shafts 14, 15, and fit closely against the valve faces f, g.. The pistons 7 work in chambers 69 formed in the cylinder bodies, and the rods of these pistons are held in place by the pressure of the ring 17 in one case and the pressure due to liquid pumped by the replenishing pump in the other. A spring 43 abuts against a collar on the shaft 15 and the cylinder body 6 in order to keep the latter on its seat, when all other pressure is removed. Concentric channels 71, 72, communicating with regions of reduced pressure, are formed on the cylinder face in order to reduce the pressure tending to force the cylinder body from its seat. To oppose and neutralize this force, the outlets 70 from the cylinders are made of smaller area than the bore of the cylinders 69. Other means may be adopted for obtaining a pressure to keep the cylinders on to the valve faces. The valve-plate 8 has two channels 50, 51 on one face and two, 55, 57, on the other face, as shown in Figs. 3 and 4. Each of these channels extends half way round the plate except for a space h so that half the cylinders may open into one port and the other half into the other port, thus giving free communication between the sets of cylinders on either face of the valve-plate. The replenishing pump consists of a plunger 9 working in the bore 66. This plunger is hollow, and a rod 19 within it is operated by a pin 31 worked from the end of the shaft 15. The motion 8 of this rod is transmitted to the plunget through a spring 32, so that, when the resistance to the plunger 9 exceeds a certain limit, the latter ceases pumping. As shown in Fig. 2, the pump draws oil from the well 75 and delivers it through valves 34 to the main pumping system, which is provided with air vessels 65 or their equivalents. The action of the pump also serves to keep the ball ends of the connecting-rods 42 on their seats during what may be regarded as the suction stroke of the pistons 7, so that positive connexion between the socket ring and the pistons may be dispensed with. In order to maintain a constant circulation of oil throughout the apparatus, the spacing of the connecting-rod sockets in the socket rings has to be adjusted to allow for the inclination of the latter. The method of spacing is shown in Figs. 18 and 19. The line v-v<1> indicates diagrammatically the plane of the socket ring in a vertical position, the projection of the ring on the face of the cylinder body 6 being then a circle F. The line t-t<1> indicates the ring in an inclined position, the projection then being an ellipse E. The scheme is shown in Fig. 18, where the dotted circles show the location of the cylinders and the solid circles show the location of the sockets. This result may be arrived at by other means. In addition to the means, such as the channels 71, 72 for reducing the effective widths of the raised seat of the valve faces, the width of this seat may be still further reduced. The number of cylinders formed in the body 6 may be uneven, and the plate 8 may be rigid instead of pivoted.