27,219. Dunn, W. Nov. 26. Fixed-abutment type; discharge and suction passages; valve-gear.-Hydraulic power-transmission mechanism primarily adapted for use on automobiles comprises, (1) a pump of the hingedvane type embodying a number of rotors of differing capacities, the vanes or pallets being driven into contact with the eccentric pump chamber by centrifugal force, (2) controlling- means for the liquid comprising a valve having two compartments each of which has a cut-away portion to uncover certain of the discharge passages of the rotor elements, the valve being given a rotary and longitudinal movement, (3) motor elements mounted on two shafts in axial alinement, the motor elements comprising two sets of similar pallet rotors, one set for forward running, the other for reversed running, the oscillating pallets in both sets being forced into operative engagement with the eccentric casing by springs, and (4) pedal-actuated brake and control valves for checking the flow of fluid from the motors. Figs. 4, 6, and 8 show the pump element. The driving-shaft 5 passing through the casing 6 carries a web 7 from which extends a series of bolts 8 supporting a number of plates or spiders 9. Supporting-plates 10 also carry the bolts 8. A number of pivoted oscillating pallets 12 are arranged in the spiders 9 and engage the eccentric bore 15 when the shaft 5 is rotated by reason of centrifugal force acting on their weighted ends 14. A fluid storage receptacle mounted on the rear of the chassis driver communicates with a conduit 20, which communicates directly with the inlet chamber 21 of the casing 6. Liquid delivered to the chamber 21 is acted upon by the pumps and delivered to ports 22 and passages 23 in a cylindrical valve housing 24 bolted to casing 6. The shaft 26 journaled in the housing 24 is squared to actuate the rotary valve 27. This valve is a hollow cylindrical casting sealed at the top and centre by webs 28, 29 shown in Fig. 9. All the wall in the upper half of the valve is cut away except a part 30 of sufficient size to cover the upper parts of the ports 23. The wall of the lower half is cut away to form a port 31 corresponding in size to the part 30. By this means all the ports 23 not uncovered by the rotation of the valve 27 are short-circuited back to the passage 21. The valve 27 is rotated to place one or more ports 23 in communication with the rear motors by the following means:-A gear-wheel 32 mounted on the shaft 26 meshes with a sector 33 secured to a shaft 34, to which is also secured the lever arm 38 carrying pins 39, 40. The pin 39 moves in a slot 41 on the rod 42 operated from the cross-shaft 44. The pin 40 moves in a slot 45 on the rod 46 also operated from the shaft 44. The latter is actuated from the lever 53 on the steering-wheel by levers 48, 49, Fig. 16. It is clear that the power transmitted to the back axle motors is controlled by the rotary movement of the valve 27 uncovering more or less of the ports 23. The fluid forced through the upper half of the valve 27 passes through the conduit 57, connexion 58, and flexible pipe 60 to a reversing-valve casing 61, Fig. 2. This valve casing encloses a reversing-valve 69 actuated by a shaft 66 carrying rocker arms 67, Figs. 11, 13, and 14. The rear motor casing 65 is divided into two compartments by a web 75, which supports the two independent rear axles 77, 78. Two end plates 79, 80 close the ends of the casing 65 and provide bearings 81, 82. The supporting- plate 89 secured to the shaft 77 carries spiders 91, 92 on either side. These spiders carry in turn substantially semi - cylindrical rotary pallets 94, 96, the notched ends 97 of which are arranged to give forward running in one case and reversed running in the other. The fluid-tight end rings 100, 101, the plate 89, and the spiders 91, 92 are held together by bolts 102. The end plates 100, 101 and the plate 89 carry the pivots 103, 105, 104 for the pallets 94, 96. The notched ends 97 are held in contact with the eccentric wall of the working chambers by springs 107, which are put under an initial torsion by twisting and clamping the small end plate 106, shown in Fig. 12. The shaft 78 carries a rotor mechanism similar in all respects to that carried by the shaft 77. The port 109 carries liquid in equal quantities to the segments 94 of each rotor element, and after acting upon the ends 97 the liquid escapes by cross-passages 110 to the rear faces of the pallets 96, which serve to assist the delivery of the liquid to the port 111 and by way of the valve 69 to the exhaust port 112. Since both rotor mechanisms are fed by the same valve the shafts 77, 78 may be driven differentially. The car is reversed by sliding the valve downwards through the medium of simple lever and link mechanism operated from the rocker arm 116 carried by the spindle 117. This spindle is rotated through the medium of the lever 118, rod 119, roller 121, and cam 120, by the cross-shaft 44, which in turn, as already described, is moved by the lever 53. The contour of the cam is such that no movement of the rod 119 occurs when the lever 53 is moved in an anti-clockwise direction for forward running. A spring 122 returns the rod 119 to normal position when the lever 53 is moved from the reverse position to its neutral position. When the valve 69 is so moved to uncover the part 111 and cover the ports 112, 109, liquid is fed under pressure to the pallets 96 and passages 99 and finds exit in the manner described by way of the passages 110, 98, 109 to the exhaust port 112. Liquid is led from the port 112 to the coupling 126 on the valve housing 59. The latter comprises two cylindrical chambers 129,130, the chamber 130 enclosing a chamber 131 and communicating therewith by ports 132, which may be wholly or partially closed by the rotary brake valve 133. The chamber 131 communicates with the chamber 129 through the conduit 20 and spring-loaded check-valve 136. Immediately above the check-valve 136 is another spring-loaded check-valve 140. The liquid in passing from the motors to the pumps must pass through the ports 132, which may be so reduced in area as to restrict the flow of the liquid sufficiently to serve as a powerful brake. In order to prevent the slide valve from being moved from its seat by the fluid forced against it when the valve 133 is actuated, extensions 69<a> on the valve slide in recesses in the valve casing 61. The brake valve is operated from the pedal 149 by a sleeve 148, lever 150, and link 151, which carries a fulcrum 152 for a lever 153. One end of the latter operates a spindle 156, through a rocker-arm 155, Figs. 15 and 4. The other end of the lever 153 operates the spindle 162 through lever and link gear 157, 158, 160, 161. The link 157 is held by a spring 157<a>. The spindle 162 is secured to the brake valve spindle. The fulcrum 152 is so positioned between the links 154, 157 as to operate the former first and more strongly. By this means the valve 27 is lifted by the gear 165, 166, 167 to close the passage 57 and shortcircuit the pumps before the brake valve is operated. In consequence a partial depression of the pedal 149 causes a similar action on the gear to that of disengaging the clutch, the liquid from the rear motors passing from the chamber 131 through the valves 136, 140 back to the rear motors again. A full depression of the pedal operates the braking valve 133 in addition to the control valve 27. Should the car tend to drift backwards, the reverse motion of the rear motor mechanism would cause the fluid to be pumped back through the flexible pipe to the chamber 129. The non-return valve 140, however, prevents any passage of liquid and consequent running-back of the car. Should the pressure in the chamber 129 become excessive, a safety-valve 170, Fig. 7, permits the passage of liquid to the passage 20. This valve is held down by a spring 174 adjusted by a screw 175. The upper part of the cylindrical body of the valve is made of larger diameter than the lower to form a shoulder 178 on which the liquid may act. A similar safety-valve 179 is placed between the chambers 130, 131.