Patent GB-189714826-A (GB)
Title: Improvements in or relating to Power-transmission Apparatus.
Inventor: HALL JOHN WILLIAM
Filed: 1897-06-18
Granted: 1898-08-18
Abstract: 14,826. Hall, J. W. June 18. Revnlving-cylinder type.-Refers to the apparatus described in Specifications Nos. 6590 and 7479, A.D. 1896, and relates to means for correlating the adjustment of the motor crank-pin J with that of the short-circuiting valve K, to means for independently operating the said valve, to a valve gear for the motor G by which the angular advance of the eccentric Q is maintained constant for any position of the crank-pin J, to means for cooling the circulating fluid, and to the provision of a relief valve between the pump and the motor. The worm-wheel J<2>, which is used to rotate the eccentric shaft J<1> carrying the crank J, is provided with a cam J<5> on its boss J<7>, which cam actuates a lever acting upon the outer end of the rod N, the inner end being connected by suitable links and levers with the short-circuiting valve K. The lever acting on the end of the rod N can also be actuated by hand to open the valve in any position of the wheel J<2>, but a catch is arranged to prevent the return of the lever till the wheel J<2> is turned back to the position in which the cam J<5> holds the valve open, thus rendering impossible the closing of the valve when the gear is in an unsuitable position. The position of the wheel J<2> in which its cam J<5> holds the valve open is that in which the throw of the crankpin J is nil. This is the position for starting, a range of adjustment being permitted of 360‹ in the forward direction and 180‹ in the rearward direction. During the first 180‹ forward the valve K is being gradually closed and the crank J gradually lengthened till the valve is fully closed and the crank J at its maximum throw, when the apparatus transmits its maximum force and the speed is reduced in a proportion depending on the respective capacities of the pump and the motor. During the next 180‹ movement of the wheel J<2> the valve K remains closed and the throw of the crank J gradually diminishes again to nil, the speed of the driven part increasing till it equals that of the driving-shaft A. During the 180‹ backward, the action is similar to that of the first 180‹ forward, except that, owing to the construction of the valve gear, the motor is reversed, and the rotation of the shaft A is transmitted in a reversed direction. In the valve gear the eccentric Q which turns on the stud R concentric with the main axis of rotation X Y is driven by a projection J<9> from the shaft J', the connection being made through a toothed wheel J<8> gearing with an internally-toothed wheel Q<6> on the eccentric block. The wheel Q<6> has double the number of teeth of the wheel J<8>, and the pitch line of the latter passes through the axis of the crank-pin J so that the relative motion of the said axis and eccentric is a straight line through the main axis of rotation X Y. When it is desirable to cool the circulating fluid, the pump and motor crank chambers are separated by a partition D<4> and the fluid passed through a cooler by the passage O. The relief valve above referred to is fitted to the pump delivery pipe, and consists of a spring-loaded piston forming a bye-pass to the crank chamber. The Provisional Specification describes an arrangement for compensating for change of volume of the liquid inside the casing ; it consists of a cylinder having a piston which is spring-loaded or connected to an accumulator. Alternative arrangements of gear for the short-circuiting valve K and the eccentric Q are also described, the short-circuiting valve being actuated by a screw-threaded nut and toothed wheels from the shaft J', and the eccentric by projections from the crank-pin.