15,121. Sundh, A. June 23. Movable abutment type; plant; valve-gear.- Hydraulic power-transmission apparatus comprises pumping-mechanism adapted to deliver liquid at a variable rate of flow and pressure for operating the motor. The pumps are arranged so that they can be connected together in series, multiple-series, and parallel, a cylindrical suction-valve chamber and a deliveryvalve chamber being made common to all the pumps, and a series of piston valves in the chambers being connected so as to operate together. Fig. 1 is a sectional elevation of the pumping-mechanism, and Fig. 2 is a sectional elevation in a plane at right-angles to that of Fig. 1. The pumping-mechanism, preferably of the Roots'-blower type with substantially semicircular teeth, is arranged within a casing A. The pump proper is arranged in four sections 1, 2, 3, 4. The driving-shaft 5 is coupled to the shaft 8 by gearing 9. In each pump section is a pair of intermeshing pump gears 10 keyed to the shafts 5, 8. The casing A is filled, or partly filled, with liquid. The pump casing C is formed with a valve chamber 15, in which is located a rotary valve comprising a stem and valves a, b, c, d, e. Above the pump gears is arranged in the chamber 16 another valve v<1> comprising valves a<1>, b<1>, c', d', e<1>. Above the valve chamber 16 is a pressure chamber 17, in which are mounted spring-loaded check valves 1<a>, 2<a>, 3<a>, 4<a>, which control parts 20 leading from the valve chamber. A pressure port 21 extends from the chamber 17 to the reversing-valve 22 controlling the direction of the flow of liquid to the motor M. This motor, which may be of any construction, is shown of the radial-cylinder type, liquid being fed to the cylinders from the motor valve 28 by ports 27. The mechanism for operating the valve V, V<1> is shown in Figs. 1, 4 and 5. The spindles of the valves are connected to the ends of the lever 32, which is pivotally mounted on a rocking shaft 33. A vertical cam-plate 34 is provided with a rack 35, and is operated by the hand-wheel 39 through the gear shown. This cam-plate has a cam-slot 40 formed on one face, in which engages a lug or anti-friction roller 41, carried by the lever 32. A vertical slot 42 is also formed on the cam-plate through which the rocking-shaft 33 extends. Keyed to the rocking-shaft is a short arm 44, carrying a roller 45 engaging a cam-slot 46 in the plate 34 opposite the slot 40. A rocking-arm 47 is keyed to the shaft 33 and operates the reversing-valve 22. By suitably positioning the valves V, V<1>, the liquid may be made to pass (1) through all the pumps and back to the casing so that the pumps are running idle as shown in Figs. 7, (2) through all the pumps and to be delivered to the motor through a valve 1<a>, (3) through two pumps and to be delivered to the valves 1<a>, 3<a>, or (4) through one pump only and to be delivered through all the valves 1<a>, 2<a>, 3<a>, 4<a>. An emergency intake valve and a relief valve may be fitted to the pressure chamber 17.