BRAKE CONTROLLED PRESSURE MODULATING CLUTCH VALVE

• US 3,850,273 A
• Filed: 09/17/1973
• Issued: 11/26/1974
• Est. Priority Date: 09/19/1972
• Status: Expired due to Term

• Current Assignee: Noboru Murakami
• Original Assignee: Noboru Murakami
• Inventors: Murakami, Noboru
• Primary Examiner(s): Wyche, Benjamin W.
• Application Number:
  US05/397,920
• Time in Patent Office: 435 Days
• Field of Search: 192/19F,87.19,4A,4C
• US Class Current: 192/221
• CPC Class Codes: B60T 11/103 in combination with other control devices conjoint control of brake system and at least another sub-unit B60W10/188
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 30/18063 Creeping
• CPC Class Codes: F16H 2059/088 Fast forward-reverse-sequence mode
• CPC Class Codes: F16H 59/54 dependent on signals from the brakes, e.g. parking brakes
• CPC Class Codes: F16H 61/0274 Control units where shifting is directly initiated by the driver, e.g. semi-automatic transmissions generation of movements for final actuating mechanisms F16H61/28
• CPC Class Codes: Y10T 137/7798 Ancillary reactor surface responds to inlet pressure

Abstract

An inching control system for controlling the fluid pressure to be applied to the fluid-actuated clutch engaging mechanisms of an industrial vehicle in response to the braking operation. In the control system, a modulator valve for controlling the fluid pressure to be applied to the clutch engaging mechanisms in manual shifting operation is designed to effect the inching movements of the vehicle.

Claims

1. An inching control system for a vehicle having a manual shift valve for selectively supplying the line pressure from a pressure source of the vehicle at a predetermined value to fluid-actuated clutch engaging mechanisms and a hydraulic braking system for arresting the movements of the vehicle, comprising a modulator valve for modulating the line pressure to be supplied to said clutch engaging mechanisms responsive to the operation of said manual shift valve, said modulator valve including a housing, a valve spool reciprocable within a cylindrical bore of said housing and forming a first pressure chamber to be selectively connected with said clutch engaging mechanisms and to modulate the line pressure, a modulator piston reciprocable within said bore and forming a sEcond pressure chamber which is directly connected with said first pressure chamber by a passage way having an orifice, said modulator piston being provided with a pressure receiving area which is larger than that of said valve spool and a resilient means interposed between said valve spool and modulator piston for normally biasing said valve spool to its inoperative position;

and inching means directly connected to said modulating piston for controlling the movements of said modulator piston in response to the operation of said braking system to effect the inching movements of the vehicle, whereby the movements of said modulator piston regulate instantly the line pressure to be supplied into said clutch engaging mechanisms during the inching movements of the vehicle.

2. An inching control system as claimed in claim 1, wherein said inching means is a fluid actuator including an inching piston operated by pressurized braking fluid from said braking system, said inching piston being operatively connected with said modulator piston of said modulator valve.

3. An inching control system as claimed in claim 2, wherein said actuator comprises a casing mounted on said housing of said modulator valve, said inching piston reciprocable within said casing to form a pressure chamber to receive therein the pressurized braking fluid and an operation rod for connecting said inching piston with said modulator piston of said modulator valve.

4. An inching control system as claimed in claim 1, wherein said inching means comprises an inching plate to be mechanically operated by depression of the brake pedal of said braking system and an operation rod to connect said plate with said modulator piston of said modulator valve.

5. An inching control system as claimed in claim 1, wherein said inching means comprises an inching piston slidably and co-axially coupled with said valve spool within said bore of said modulator valve to form a third pressure chamber, a second resilient means interposed between said inching piston and modulator piston to urge said modulator piston against the fluid pressure applied into said second pressure chamber only when the line pressure to be supplied to said clutch engaging mechanisms is supplied into said third pressure chamber in accordance with depression of the brake pedal of said braking system and means for selectively communicating the line pressure to said third pressure chamber in response to the operation of said braking system.

6. An inching control system as claimed in claim 5, wherein said last mentioned communicating means comprises a conduit for communicating the line pressure to be supplied to said clutch engaging mechanisms into said third pressure chamber and an inching regulator valve disposed within said conduit to regulate the line pressure supplied into said third pressure chamber in response to the operation of said braking system.