Power plants – Pressure fluid source and motor – Pulsator
Patent
1990-10-31
1992-02-25
Look, Edward K.
Power plants
Pressure fluid source and motor
Pulsator
60585, 60533, 91196, 91217, 92248, 92118, B60T 1128, B15B 700
Patent
active
050902016
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a fluid pressure actuator and is particularly, but not exclusively concerned with a fluid pressure actuator for controlling the clutch or brakes of a vehicle.
Hitherto, it has been commonplace to use a pedal in a vehicle which applies pressure and displacement to a pushrod arranged to operate a piston contained within a separate hydraulic master cylinder assembly. The pressure is then transmitted through a hydraulic line to operate a hydraulic slave cylinder for operating, e.g., a clutch of the vehicle.
It has been proposed hitherto to provide a pedal having a cylinder thereon for operating a remote slave cylinder. Examples of such pedals are described in WO87/03344 and EP-A-0293082.
In WO87/003344, it is necessary to provide a camming arrangement which causes a piston to move into the cylinder during pivoting movement of the pedal. In EP-A-0293082 it is necessary for the cylinder to be pivotally mounted on the pedal and for an operating rod of the piston to be pivotally mounted to a bracket on the vehicle bulkhead.
An object of the present invention is to provide an improved actuator which, in particular, avoids the need for a camming device.
According to the invention there is provided a fluid pressure actuator comprising a cylinder rigid with a lever to be mounted for pivoting about an axis, the piston being axially slidable in said cylinder, the piston having an operating member extending therefrom to be mounted at a position remote from the piston for pivoting about a further axis spaced from the axis of pivoting of the lever, the operating member being arranged to tilt relative to the cylinder during pivotal movement of the lever.
With there being one pivotal mounting for the lever and one pivotal mounting for the operating member, an additional pivot as in EP-A-0293982 is not required and it is unnecessary to provide a caming arrangement as described in WO87/03344.
The tilting of the operating member relative to the cylinder can be accommodated by appropriate shaping of the piston. For example, the piston may be tapered from a position adjacent one end to enable it to tilt within the cylinder or it may alternatively be barrel-shaped. Such an arrangement provides a simple and convenient way of accommodating the tilting movement of the piston and is particularly advantageous in that respect.
The operating member may be a tubular rod through which fluid from the actuator passes to operate a device such as a slave cylinder. The tubular rod may be connected to or may be integral with a hollow mounting through which fluid passes. The axis of pivoting of the tubular rod may, in such a case, be an axis of pivoting for the hollow mounting. The hollow mounting may include passage means for communication with a reservoir. The reservoir may be of a remotely located type connected to the hollow mounting by means of a suitable conduit.
The operating member may be associated with a valve which enables the cylinder to communicate with a reservoir when the piston occupies a given position within the cylinder. The valve may comprise a seal associated with the operating member which may be arranged to permit or prevent communication with the reservoir. The seal may be an annular seal arranged to engage a surface surrounding an orifice leading to, e.g., the slave cylinder.
The operating member may be axially rigid with the piston and movement of the cylinder towards a rest position may permit the operating member to cause the valve to permit communication with the reservoir. Movement of the piston away from the rest position may then cause the valve to engage the surface around the orifice to inhibit communication between the cylinder and the reservoir.
The valve may be at an end of the operating member adjacent the piston.
In another embodiment the operating member may be axially movable relative to the piston and movement of the piston towards a rest position may, in that case, cause the operating member to operate the valve so as to permit communication with the reservoir.
The reservoir may
REFERENCES:
patent: 2525740 (1950-10-01), Trevaskis
patent: 3399786 (1968-09-01), Honeycut
patent: 4910962 (1990-03-01), Keane
patent: 4924673 (1990-05-01), Barker et al.
patent: 4944215 (1990-07-01), Nimmo et al.
Automotive Products plc
Denion Thomas
Look Edward K.
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