Fluid compensating device for hydraulic ratio changer power brake booster

Claim 2

In a hydraulic power boost mechanism having a working chamber and a control valve in communication with an inlet pressure source and a fluid reservoir for controlling the pressure in the working chamber and a power piston having an end exposed to the working chamber and an output plunger on said end sealingly projecting beyond the working chamber, and a hydraulic ratio changer operatively connected to the control valve and to the power piston and including a control chamber into which the output plunger projects and further includes a manually operated input plunger axially aligned with the output plunger and slidably displaceable in the control chamber from a released position to an applied position for generating fluid pressure in the control chamber to displace the control valve, the improvement which comprises: a device in communication with the fluid source and operatively connected to the input plunger to be actuated thereby when in released position to compensate for loss or gain in volume of fluid in the control chamber.

Claim 3

The improvement in claim 1 wherein said device includes a passage communicating the control chamber to the fluid reservoir, a valve in the passage urged toward closed position by resilient means, and an actuating pin operatively connected to the valve and the input plunger for placing the valve in open position when the input plunger is in the released position.

Claim 4

The improvement in claim 2 wherein the valve further includes a seat in the passage, a valve member slidable in the passage and urged toward the seat by the resilient means, said valve member having a transverse opening therein through which the actuating pin passes, said actuating pin being pivotally suspended at one end with the other end operatively connected to the input plunger so that the central portion of the actuating pin which passes through the transverse opening engages the valve member to permit controlled seating of the valve member.

Claim 5

The improvement in claim 3 wherein adjustable means is operatively connected to the valve member and to the pin to thereby control seating of the valve member and input plunger displacement relative to control valve position.

Claim 6

In a hydraulic power boost mechanism having a working chamber and a spool valve for controlling pressure in the chamber and a piston having an end exposed to the chamber and an output plunger integral with the piston and having an end sealing projecting beyond the chamber, and a hydraulic ratio changer operatively connected to the spool valve and to the piston and including a control chamber into which the output plunger end projects and further including a manually operated input plunger having an end extending into the control chamber and displaceable therein from a released position to an applied position for generating fluid pressure in the control chamber, said spool valve having an end portion exposed to the control chamber pressure and responsive thereto for controlling the working chamber pressure, the improvement which comprises: valve means connected to the input plunger for opening the control chamber when the input plunger is in released position to compensate for loss or gain in fluid in the control chamber and for closing the control chamber when the input plunger is moved in the applied position, said input plunger end being in axial alignment with and spaced from the output plunger end to provide a gap between said ends when the input plunger is in released position so that displacement of the input plunger toward an applied position closes said valve means before engagement between said ends to thereby increase the rate at which the control chamber pressure rises.

Claim 7

In a hydraulic power boost mechanism having a working chamber and a spool valve for controlling pressure in the chamber and a piston having an end exposed to the chamber and an output plunger integral with the piston and having an end sealing projecting beyond the chamber, and a hydraulic ratio changer operatively connected to the spool valve and to the piston and including a control chamber into which the output plunger end projects and further including a manually operated input plunger having an end extending into the control chamber and displaceable therein from a released position to an applied position for generating fluid pressure in the control chamber, said spool valve having an end portion exposed to the control chamber pressure and responsive thereto for controlling the working chamber pressure, the improvement which comprises: valve means connected to the input plunger for opening the control chamber when the input plunger is in released position to compensate for loss or gain in fluid in the control chamber and for closing the control chamber when the input plunger is moved in the applied position, said input plunger end being in axial alignment with and spaced from the output plunger end to provide a gap between said ends when the input plunger is in released position so that displacement of the input plunger toward an applied position closes said valve means before engagement between said ends to thereby increase the rate at which the control chamber pressure rises.

Claim 8

The improvement in claim 5 wherein said valve means includes a passage communicating the control chamber with a fluid exhaust port, a seat in the passage, a valve member urged Onto the seat by resilient means, and an actuating pin operatively connected to the valve member and to the input plunger for moving the valve member off said seat when the input plunger is released.

Claim 9

The improvement in claim 6 wherein said valve member is formed with a transverse opening through which the actuating pin passes, said pin being pivotally supported at one end with the other end operatively connected to the input plunger so that the central portion of the pin which passes through the transverse opening engages the valve member to permit controlled seating of the valve member.

Claim 10

The improvement in claim 7 wherein said valve member is provided with adjustable means operatively connecting the valve member with the pin so that fluid displacement from the control may be controlled to provide the desired spool valve response.

Claim 11

In a hydraulic power boost mechanism having a working chamber and a spool valve for controlling pressure in the chamber and a piston having an end exposed to the chamber and an output plunger integral with the piston and having an end sealingly projecting beyond the chamber, and a hydraulic ratio changer operatively connected to the spool valve and to the piston and including a control chamber into which the output plunger end projects and further including a manually operated input plunger having an end extending into the control chamber and displaceable therein from a released position to an applied position for generating fluid pressure in the control chamber, said spool valve having an end portion exposed to the control chamber pressure and responsive thereto for controlling the working chamber pressure, the improvement which comprises: valve means responsive to differential pressure for communicating the control chamber with a fluid source upon intial release of the input plunger from an applied position so that the volume of fluid in the control chamber is partially replenished before the input plunger is moved to its released position.

Claim 12

In a hydraulic power boost mechanism having a working chamber and a spool valve for controlling pressure in the chamber and a piston having an end exposed to the chamber and an output plunger integral with the piston and having an end sealingly projecting beyond the chamber, and a hydraulic ratio changer operatively connected to the spool valve and to the piston and including a control chamber into which the output plunger end projects and further including a manually operated input plunger having an end extending into the control chamber and displaceable therein from a released position to an applied position for generating fluid pressure in the control chamber, said spool valve having an end portion exposed to the control chamber pressure and responsive thereto for controlling the working chamber pressure, the improvement which comprises: valve means responsive to differential pressure for communicating the control chamber with a fluid source upon intial release of the input plunger from an applied position so that the volume of fluid in the control chamber is partially replenished before the input plunger is moved to its released position.