Patent GB-190404638-A (GB)
Title: Improved Variable-speed and Reversing Gear for Motor-cars and other uses.
Inventor: HUMPAGE THOMAS
Filed: 1904-02-25
Granted: 1905-01-26
Abstract: 4638. Humpage, T. Feb. 25. Lathes.-Relates to hydraulic transmission of power, and consists in the combination of several rotary pumps or motors of special construction to form a variable-speed and reversing-gear for lathes and for other purposes. Fig. 1 shows a longitudinal section through a variable-speed arrangement, and Fig. 2 a section on the line C-D of Fig. 1. The pumps or motor, shown particularly in Fig. 2, consists of a rotating piston 22, provided with vanes 24, pressed outwards by spring-actuated plungers 25. The piston rotates within a non- rotating casing, the vanes bearing against an internal eccentric surface a, b, c, d, composed of arcs of circles. When used as a pump, the oil or other liquid is drawn by the vanes, as they rotate in the direction shown by the arrow, through grids 27 to the part 26 and discharge passage 28. The piston rotates in the reverse direction when the arrangement is used as a motor. A saddle 29, bearing on the surface of the piston 22, prevents leakage of oil. In a variable-speed arrangement, several such devices are arranged in a casing 3 having strengthening-partitions 10 provided with apertures 11 for free circulation of oil. Stay-bolts 12 connecting the bodies of the pumps and motors also pass through the apertures 11. The pump 2, which is driven by the motor shaft 1, gives a constant supply of oil to the motors 4, 5, 6, 7, 8, which are of varying size, and rotate with the driven shaft 9. One or more of the motors may be cut out, so that the remaining motors may drive the shaft 9 at a higher speed. The valve controlling the supply of oil from the pump 2 to the motors consists of a hollow cylinder 13, closed at the ends and provided with ports. The valve is rotated by giving a longitudinal movement to the collar 32, which is keyed to an extension of the casing 3, the collar being provided with a spiral rack 33 gearing with a segment 31 connected to the valve. In the first position of the valve 13, the motor runs freely, the oil then passing from the passage 28 through the ports 14, 20 and returning to the casing 3. On turning the valve to the next position, the port 20 is closed, and the ports for all the motors simultaneously opened, the oil passing through the valve to the motors and driving them at the lowest speed. Movement of the valve to the next position cuts off the motor 8, so that the remaining motors drive the shaft 9 at the next highest speed. Further movement of the valve cuts off the remaining motors in succession, until all the motors are cut off, when the whole arrangement rotates with the shafts 1, 9. A ratchet or free-wheel device prevents rotation of the casing 3 reversely to the driven shaft 9. Reversing may be effected by providing a motor with the vanes reversed. The motors may vary in diameter instead of width, or in both these dimensions. The pump may be contained in a separate casing and may communicate with the motors by a pipe or channel. The oil is kept at a constant pressure by an arrangement consisting of two leather pist ms 40 connected by a spring 41 anchored in the middle, oil being contained between the pistons, which move in a cylindrical chamber 39, open at; the ends. Ventholes 45 relieve undue pressure of the oil. In the modification shown in Fig. 6, the pump 44 supplies oil to any one of the three motors 45, 46, 47 through the valve 54. Pinions of different sizes, mounted on the shafts of the motors, gear with internally-toothed wheels fixed to the driven shaft, so that the speed ratio depends upon which motor is in operation.