Patent GB-190811723-A (GB)
Title: Improvements in and connected with Hydraulic Transmission of Power.
Inventor: HELE-SHAW HENRY SELBY
Filed: 1908-05-29
Granted: 1909-06-01
Abstract: 11,723. Shaw, H. S. Hele-. May 29. Hydraulic transmission of power.-Two hydraulic devices, each of which can act as a motor or pump, are connected by a hollow shaft forming liquid conduits, so that the circulation of liquid sets up a relative rotary motion between the two devices. One of the devices is provided with means for varying the capacity of the active parts of cylinders forming part of the device from zero to a maximum. Means are also provided for connecting and disconnecting one of the relatively rotating mechanical members with the other similar member. Arrangements in connexion with the circulation of the liquid are made such that the fluid circulates from one device to the other whether the rotating members are clutched or declutched for driving purposes, and thus the transmission of power is effected independently of the clutching and declutching of the rotating members. Fig. 1 shows a longitudinal section of one form of the hydraulic gear, and Fig. 2 a similar view of a modified form of the apparatus. The cylinders a' of one of the hydraulic devices A are coupled to the driving-shaft c, and the cylinders b<1> of the other device B are coupled to the driven shaft. The two parts A, B communicate through the hollow shaft E, which is formed on the one side by an external tube e' coupled to the driving-shaft and an internal tube e<3> connected to the tube e<1>, and on the other side by tubes g, g<1> connected to the crank-disk g<2> which also carries the crank-pin h of the device B. A normally non- rotatable valve f is located between the cylinders a' and the tube e', and is provided with ports f<1>, f<2> communicating with the space between the tubes e', e<3>, and with the interior of the tube e<3> respectively. The disk g<2> is provided with inwardly projecting flanges g<3>, g<4> provided with ports g<5>, g<6>, which also communicate with the annular space between the tubes and with the central space of said tubes. The pistons a of the device A are connected to eccentric rings i which run on races carried in a sliding but non-rotatable frame i<2>. Between the devices A, B is arranged the clutching-apparatus C. The outer casing j of this is permanently fixed to the framework of the whole apparatus. The member is rigidly attached to the tube e', and consequently revolves with the cylinders a' of the device A. Keyed upon the tube g is the sleeve j<2> which forms the other essential member of the clutch. In the apparatus shown in Fig. 2, the central tubular shaft K is so constructed that its end forms the crank h, the inner ends of the cylinders b<1> communicating with the shaft K by the port K<4>. The shaft K is constructed in two portions connected by the running joint K<3>. The piston-rods b<3> are connected to the rotatable framework l. The form of clutching-device differs from that shown in Fig. 1. The cone m<2> is keyed to a sleeve fixed to the stationary casing m ; the cone n is keyed to the sleeve n<1> which is itself keyed to one part of the shaft K, and the sliding cone member o is secured to the sleeve o<1> keyed to the other part of the shaft K. Dogs fitted to the sleeves and to the cone member o give positive engagement after the initial engagement of the conical portions. The crank h can therefore be connected directly to the shaft of the first hydraulic device A, by operating the member o in one direction, or it can be held stationary by operating the member o in the opposite direction. The valve f, similar to that shown in Fig. 1, is provided with suitable reversing- mechanism. The operation of both modifications is as follows :-If the shaft of the device B is free from the frame and from the pump A, the liquid forced by the pump merely causes the idle rotation of the crank h. If the crank h is clutched to the frame, the liquid forced from the device A imparts rotary motion to the cylinders b<1> and thus to the driven shaft, the eccentricity of the rings i being varied in accordance with the hydraulic pressure required. If the valve f is now turned into its alternative position, the reversal of the driven mechanism takes place. If, however, instead of having the cylinders a' of the first device A and the shaft of the second device B declutched and the brake applied, the two are clutched together and the brake is released, the cylinders a<1> turn in the same direction as the crank h, and the liquid tends to drive the cylinders b<1> in the reverse direction. If the eccentricity of the rings i be made equal to that of the crank h and the number and bore of the cylinders in each system is equal, then the speed at which this driving occurs is the same as that at which the first set of cylinders a' is driven forwards, and the resultant speed of the second set of cylinders b<1> is therefore zero relatively to the frame. By reducing the eccentricity of the rings i, the second set of cylinders may be made to move slightly forwards, and this action can be increased until there is no eccentricity of the rings i, and consequently no flow of liquid, and the two sets of cylinders a<1>, b<1> revolve together.