Fail operative split tandem valve

• US 3,933,176 A
• Filed: 07/12/1974
• Issued: 01/20/1976
• Est. Priority Date: 07/12/1974
• Status: Expired due to Term

• Current Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Original Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Inventors: Wheeler, Mildred S.
• Primary Examiner(s): Cohan, Alan
• Assistant Examiner(s): Michalsky, Gerald A.
• Application Number:
  US05/488,036
• Time in Patent Office: 557 Days
• Field of Search: 91/367, 91/384, 91/411 A, 91/413, 137/596, 137/596.12
• US Class Current: 137/596
• CPC Class Codes: F15B 18/00 Parallel arrangements of independent servomotor systems
• CPC Class Codes: F15B 2211/8757 using redundant components or assemblies
• CPC Class Codes: Y10T 137/87169 Supply and exhaust
• CPC Class Codes: Y10T 137/87177 With bypass

Abstract

A valve for simultaneous valving in two separate hydraulic systems, the valve having two slides with each slide being attached to a bypass driving member through caged spring cartridges. If one of the slides jams the other slide is moved by the bypass driving member in the opposite direction to the direction in which the jam occurred. The jammed system slide includes a porting which is opened by the relative movement of the bypass driving member, placing that system in a bypass condition. The other slide is not effected and remains in full control of a tandem hydraulic cylinder to which such valves are connected. If each half of the tandem cylinder is sized for full thrust capacity, there is no degradation in performance during the jammed condition.

Claims

1. A fail operative valve for simultaneous valving in two separate systems including:

a valve housing having first and second portions, said first housing portion having an inlet for pressurized fluid, at least one outlet for fluid return and a pair of ports for feeding the fluid to and from actuator means, said second housing portion having an inlet for pressurized fluid, at least one outlet for fluid return and a pair of ports for feeding the fluid to and from actuator means;

a first valve slide positioned in said first housing portion adjacent said first housing portion inlet, outlet and ports, said first valve slide having first and second annular passageways which are the only annular passageways therein, said first and second passageways normally valving said hydraulic fluid between said first housing portion inlet, outlet and ports to operate the actuator means, said first valve slide also having a third passageway connected to said first passageway and a fourth passageway connected to said second passageway;

a second valve slide positioned in said second housing portion adjacent said second housing portion inlet, outlet and ports, said second valve slide having first and second annular passageways which are the only annular passageways therein, said first and second passageways normally valving said hydraulic fluid between said second housing portion inlet, outlet and ports to operate the actuator means, said second valve slide also having a third passageway connected to said first passageway and a fourth passageway connected to said second passsageway; and

bypass driver means having a connection for mechanical input commands, first preloaded resilient means connected to move said first valve slide with said bypass driver means in response to the mechanical input commands up to a predetermined force, second preloaded resilient means connected to move said second valve slide with said bypass driver means in response to the mechanical input commands up to a predetermined force, a first pair of passageways positioned to complete a bypass flow channel between said first valve slide third and fourth passageways when the predetermined force is exceeded and said bypass driver means are moved by said mechanical input with respect to said first valve slide, and a second pair of passageways positioned to complete a bypass flow channel between said second valve slide third and fourth passageways when the predetermined force is exceeded and said bypass driver means are moved by said mechanical input with respect to said second valve slide, said first and second passageways of said first and second valve slides being positioned to always be in communication with said pair of ports for feeding fluid to and from the actuator means so a jam of one of said valve slides to said valve housing cannot produce hydraulic lock of the actuator means and said first and second valve slides having concentric inner and outer cylindrical surfaces, said first and second passageways thereof being annular channels in said outer cylindrical surfaces and said bypass driving means being positioned in contact with said inner cylindrical surfaces, said bypass driver means having at least one cylindrical outer surface, said first pair of passageways of said bypass driving means being annular channels in said cylindrical outer surface thereof, said fourth passageways of said first and second valve slides being positioned to always be in communication with said pairs of passageways in said bypass driving means and said third passageways of said first and second valve slides being positioned to be in communication with said pair of passageways in said bypass driving means only when the preload of said respective preloaded resilient means is exceeded.

2. The valve defined in claim 1 wherein said first and second preloaded resilient means are caged spring cartridges.

3. The valve defined in claim 1 wherein said valve housing has two outlets, said first and second passageways of said first and second valve slides are positioned with respect to said inlet and said outlets so that three conditions of flow are possible depending upon the position of said slides, a first with said inlets in communication with said first passageways of said slides and the outlets in communication with said second passageways of said slides, and a second with said inlets in communication with said second passageways of said slides and the outlets in communication with said first passageways of said slides, and a third preventing flow at said inlets and outlets.