Abstract: An antifreeze injector device for compressed air braking systems has a closed compressible bellows or compensatable rubber cylinder, the inside of which communicates with liquid to be injected and the exterior of which is subject to actuation pressure. The effective area subject to the actuator pressure being greater than that subject to the liquid to enable operator to inject into a reservoir of elevated pressure but to avoid the use of sliding pistons.

Abstract: A method of producing pneumatic brake actuator rods in which a spigot is provided at one end for mounting a pressure plate and a thread is provided on the output end, the body of the rod around the root of the spigot being under cut and thereafter upset by roll-swaging or other means to produce a flange for supporting the rod against the pressure plate so that the rod can be of generally substantially reduced diameter in relation to that used for many years hitherto.

Abstract: A tractor/trailer vehicle fluid pressure braking control system enabling two line control of trailer service and secondary braking includes for tractor braking a service brake control valve for controlling the fluid pressure applied both to service brake actuators and to a trailer service brake control line, a secondary control valve which controls the magnitude of a counteracting pressure applied to tractor spring brakes and also to a relay valve which controls a pressure in a trailer secondary spring brake control line.

Abstract: A power steering device includes a housing which journals coaxial input and output shafts. Drivingly connected to the input shaft is an eccentric which rotatably carries a gear wheel. The gear wheel is prevented from rotating in the housing so that it gyrates when the input shaft rotates. An internally toothed ring meshes with the gear wheel and is drivingly connected to the output shaft. The internally toothed ring defines a greater number of gear teeth than does the gear wheel so that gyration of the gear wheel incident to the rotation of the input shaft drives the output shaft via the internally toothed ring. A valve device is responsive to rotation of the input shaft relative to the output shaft to control fluid flow to and from a fluid motor. The fluid motor is coaxial with and drivingly connected to the output shaft so as to increase the torque derivable from the output shaft incident to rotation of the input shaft.

Abstract: An hydro-mechanical torque amplifier such as a power steering unit for road vehicles. In the prior art, torque amplifying hydraulic pressure was applied to the linear part of a ball-screw geared to the output shaft such that all power went through meshing gear teeth, necessitating robust construction thereof. In the present invention, torque amplifying hydraulic pressure is applied to a vane motor on the output shaft such that hydraulic power does not pass through gear teeth, enabling a lighter and less costly construction.

Abstract: A steering system includes a sensor device which is responsive to excessive steering effort to actuate a power assist for steering. A housing rotatably receives an input member and an output member which are rotatable relative to each other when the steering effort is excessive. The housing includes an inlet communicating with a source of pressurized air and an outlet opening to atmosphere. The input member and output cooperate to define a passage communicating the inlet with the outlet such that limited rotation between the input member and output member varies the communication of pressurized air through the passage. When the communication of pressurized air through the passage is varied, a relay valve in communication with the inlet is operable to actuate the power assist.

Abstract: A fluid power assistance control device includes a rotatable input, a first valve coupled to the input and a second valve. The second valve is rotatable relative to the first valve and a projection between the first and second valves limits the rotation therebetween. The projection cooperates with the valve to substantially define fluid paths which communicate with an outlet and also defines flow restrictions within the paths such that rotation between the valves increases flow restriction in one of the fluid paths and decreases flow restriction in another of the fluid paths. The valves cooperate to define reaction cavities which communicate with respective fluid paths so that fluid communicated to one of the reaction cavities opposes the rotation of the input.

Abstract: A load dependent control arrangement wherein an electrical load sensor such as a strain gauge controls the mark-to-space ratio of a pulse train output from a pulse generator. The pulse train operates a solenoid valve to control a pneumatic output pressure in proportion to the ratio of marks to spaces. The output pressure may be amplified in a self-lapping pneumatic relay valve. The final output pressure may be utilized in any suitable manner, for example, in operating the pneumatic brakes of a vehicle whose load is being measured by the sensor.

Abstract: A fluid flow divider having a fluid input port with passages therefrom to fluid flow paths leading to respective output ports. Said paths pass via regions acting on either side of a member which is thereby movable. Movement of said member increases a restriction in one said path while decreasing a restriction in the other said path. One of said paths further passes via a third restriction in a passage in said member such that in operation, in the event of fluid flow through the third restriction, the member is biased to concentrate flow of fluid from the input port to the one of the output ports which requires the greater fluid flow.

Abstract: An automatic slack adjuster is proposed which has an internally geared input member and an externally geared output member which is slightly eccentrically mounted within the input member and meshes with it and adjustment is achieved by moving the centre of the output member relative to the centre of the input member to effect relative rotative adjustment, the movement of the centre of the output member being achieved by rotation of eccentric bushes in which it is mounted.