US3866419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated pressure compensated load sensing system
Assignee: Parker Hannifin Corp
•
Filing: 1973-09-06
•
Granted: 1975-02-18
•
Expires: 1993-09-06
Abstract
Abstract An integrated pressure compensated load sensing system for a hydraulically actuated fork lift truck or the like having a lift cylinder, a tilt cylinder, and one or more auxiliary cylinders, said system including pump means which provides fluid pressure for acutating the respective cylinders via a directional control valve assembly including directional control valve members for controlling the direction and speed of actuation of the respective cylinders, and pressure compensating members associated with the respective directional control valve members and operative to maintain the selected speeds of actuation of the respective cylinders irrespective of variation of cylinder load. The system herein is further characterized in that when the pump means is a fixed displacement pump the valve assembly is provided with an unloading valve means operative to bypass excess pump flow to the tank thus to maintain the selected flow demand set by any directional control valve member or members. A yet further characterizing feature of the present system is that the valve assembly aforesaid with a minor modification in the unloading valve means section thereof may be adapted for use with a variable displacement pump controller means to set the variable displacement pump to meet the flow demand set by any one or more of the directional control valve members.
Inventors
- 👤 John C Paul
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:21
CPC Classifications
B; B66; B66F; B66F9/00; B66F9/06; B66F9/075; B66F9/20; B66F9/22; E; E02; E02F; E02F9/00; E02F9/20; E02F9/22; E02F9/2203; F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/0416; F15B13/0417
Claims Analysis
Total Claims: 91
Claim 1
Independent Claim
257 words
An integrated pressure compensated load sensing system comprising pump means; at least two fluid motors; a directional control valve having inlet, motor, and return ports respectively in fluid communication with said pump means, said fluid motors, and a tank; valve members movable in said directional control valve to control actuation of the respective motors and to define variable area orifices in the flow path of pressure fluid to the respective motors of sizes according to the extent of movement of the respective valve members; sensing means responsive to the pressure drops across said variable area orifices operative in conjunction with said pump means to maintain predetermined pressure drops across said orifices thus to actuate said fluid motors at desired speeds according to the sizes of said variable area orifices; check valves downstream of the respective orifices to render said sensing means responsive to the flow demand set by the valve member associated with the fluid motor of higher load pressure in the event of simultaneous actuation of said valve members; and pressure compensating members associated with the respective valve members; each pressure compensating member, when associated with the fluid motor of lower load pressure, sensing the flow demand of the variable area orifice set by the associated valve member and being moved to provide an additional restriction in one of the supply and return paths of fluid in said directional control valve thus to maintain the flow demand set by the variable area orifice of the valve member associated with the fluid motor of lower load pressure.
Claim 2
Dependent Claim
257 words
An integrated pressure compensated load sensing system comprising pump means; at least two fluid motors; a directional control valve having inlet, motor, and return ports respectively in fluid communication with said pump means, said fluid motors, and a tank; valve members movable in said directional control valve to control actuation of the respective motors and to define variable area orifices in the flow path of pressure fluid to the respective motors of sizes according to the extent of movement of the respective valve members; sensing means responsive to the pressure drops across said variable area orifices operative in conjunction with said pump means to maintain predetermined pressure drops across said orifices thus to actuate said fluid motors at desired speeds according to the sizes of said variable area orifices; check valves downstream of the respective orifices to render said sensing means responsive to the flow demand set by the valve member associated with the fluid motor of higher load pressure in the event of simultaneous actuation of said valve members; and pressure compensating members associated with the respective valve members; each pressure compensating member, when associated with the fluid motor of lower load pressure, sensing the flow demand of the variable area orifice set by the associated valve member and being moved to provide an additional restriction in one of the supply and return paths of fluid in said directional control valve thus to maintain the flow demand set by the variable area orifice of the valve member associated with the fluid motor of lower load pressure.
Claim 3
Dependent Claim
29 words
The system of claim 1 wherein one of said pressure compensating members constitutes a load check valve downstream of the variable area orifice set by its associated valve member.
Claim 4
Dependent Claim
32 words
The system of claim 1 wherein one of said pressure compensating members, when moved as aforesaid, provides such additional restriction downstream of the variable area orifice set by its associated valve member.
Claim 5
Dependent Claim
84 words
The system of claim 1 wherein one of said valve members is of three way type defining another variable area orifice in the return path of flow from its associated single acting fluid motor; the associated pressure compensating member sensing the pressure drop across said another variable area orifice and being moved by increase of the latter above a predetermined value to provide additional restriction in the return flow path thus to maintain predetermined return flow as set by said another variable area orifice.
Claim 6
Dependent Claim
75 words
The system of claim 1 wherein one of said pressure compensating members is a spring biased spool-like member axially movable in a bore in said directional control valve and having a first land constituting a load check valve downstream of the variable area orifice set by its associated valve member, and having a second land provided with metering slots defining such additional restriction downstream of the variable area orifice set by its associated valve member.
Claim 7
Dependent Claim
36 words
The system of claim 1 wherein one of said pressure compensating members constitute a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths to and from the associated fluid motor.
Claim 8
Dependent Claim
30 words
The system of claim 6 wherein one of said pressure compensating members, when moved as aforesaid, provides such additional restriction in tHe return flow path from its associated fluid motor.
Claim 9
Dependent Claim
23 words
The system of claim 1 wherein said directional control valve has a load check valve downstream of one of said pressure compensating members.
Claim 10
Dependent Claim
100 words
The system of claim 1 wherein one of said pressure compensating members is a spring biased spool-like member axially movable in a bore in said directioanl control valve and having a first land constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths acting on opposite ends of said spool-like member, and having a second land provided with metering slots defining such additional restriction in said return path, the ends of said spool-like member then being subjected to fluid pressure upstream and downstream of the variable area orifice of its associated valve member.
Claim 11
Dependent Claim
29 words
The system of claim 1 wherein one of said pressure compensating members constitutes a load check valve upstream of the variable area orifice set by its associated valve member.
Claim 12
Dependent Claim
51 words
The system of claim 1 wherein one of said pressure compensating members is a spring biased spool-like member which is axially movable in a bore in said directional control valve and which when moved as aforesaid, provides such additional restriction upstream of the variable area orifice of its associated valve member.
Claim 13
Dependent Claim
31 words
The system of claim 11 wherein said one pressure compensating member, when moved as aforesaid, has its opposite ends respectively exposed to pressures upstream and downstream of said variable area orifice.
Claim 14
Dependent Claim
77 words
The system of claim 12 wherein said directional control valve has a spring biased pilot relief valve member therein which is exposed to downstream pressure acting on one end of said spool-like member and which is opened when such downstream pressure exceeds a predetermined value whereby upstream pressure acting on the other end of said spool-like member moves the latter to restrict flow through said additional restriction to the variable area orifice of its associated valve member.
Claim 15
Dependent Claim
97 words
The system of claim 1 wherein said directional control valve has a pilot operated relief valve comprising a spring biased pilot relief member which is exposed to fluid pressure downstream of one variable area orifice and upstream of its associated check valve and which is opened upon such fluid pressure exceeding a predetermined value, and a spring biased main valve member which provides a flow path to said sensing means via said variable area orifices and check valves and which is fluid pressure actuated to restrict said flow path when said pilot relief valve member is opened.
Claim 16
Dependent Claim
83 words
The system of claim 14 wherein said main valve member is axially reciprocable in a bore in said directional control valve and has one end exposed to such fluid pressure and the other end exposed to such fluid pressure via orifice means; the opening of said pilot relief valve member effecting reduction of fluid pressure acting on said other end relative to fluid pressure acting on said one end whereby said main valve member is moved to restrict said flow path as aforesaid.
Claim 17
Dependent Claim
46 words
The system of claim 15 wherein said main valve member is a spool-like member having a groove providing said flow path and an adjacent land to restrict said flow path when said main valve member is moved by predominant fluid pressure acting on said one end.
Claim 18
Dependent Claim
81 words
The system of claim 1 wherein said sensing means comprises an unloading valve having a spring biased unloading valve member movable in a bore in said directional control valve; said unloading valve member having its opposite ends respectively exposed to fluid pressure upstream of said variable area orifices and downstream of said check valves and being moved by the pressure differential acting on said ends exceeding a predetermined value to bypass excess flow from said pump means to said return port.
Claim 19
Dependent Claim
77 words
The system of claim 17 wherein said directional control valve has orifice means communicating said downstream pressure with said return port to retain said downstream pressure at low value when said valve members are in inactive position closing said variable area orifices; said orifice means being saturated upon actuation of either or both of said valve members to establish said variable area orifice or orifices for buildup of downstream pressure for control of said unloading valve member.
Claim 20
Dependent Claim
17 words
The system of claim 18 wherein said orifice means comprises a passage in said unloading valve member.
Claim 21
Dependent Claim
29 words
The system of claim 17 wherein said unloading valve member is a spool-like member having a groove and metering slots in the adjacent land for metering such excess flow.
Claim 22
Dependent Claim
52 words
The system of claim 1 wherein said pump means comprises a variable displacement pump; and wherein said sensing means comprises a pump output adjustment means responding to the pressure drop across said variable area orifices to adjust the output of said pump according to the flow demands set by said valve members.
Claim 23
Dependent Claim
142 words
The system of claim 21 wherein said pump output adjustment means comprises a movable displacement varying member; a spring and fluid pressure actuated control piston effective to move said displacement varying member in displacement increasing direction or to permit the latter to move in displacement decreasing direction; a main spring biased controller actuated by pump delivery pressure to apply force through spring means on said control piston in displacement increasing direction and to conduct upstream pressure to act on said control piston; an auxiliary spring biased controller exposed to fluid pressure upstream and downstream of said variable area orifices and operative upon the differential of said upstream and downstream pressures exceeding a predetermined value, to open a bleed orifice from said control piston to the intake side of said pump thus to discontinue movement of said displacement member in displacement increasing direction.
Claim 24
Dependent Claim
32 words
The system of claim 22 wherein said upstream pressure is derived from the delivery side of said pump, and said downstream pressure is derived from a passage in said directional control valve.
Claim 25
Dependent Claim
21 words
The system of claim 22 wherein said upstream and downstream pressures are derived from respective passages in said directional control valve.
Claim 26
Dependent Claim
40 words
The system of claim 22 wherein another spring means acts on said control piston at zero displacement position of said displacement varying member to provide for movement of said control piston in displacement increasing direction when said pump is started.
Claim 27
Dependent Claim
31 words
The system of claim 22 wherein said main controller, upon predetermined movement in displacement increasing direction opens another bleed orifice from said control piston to the intake side of said pump.
Claim 28
Dependent Claim
35 words
The system of claim 22 wherein said auxiliary controller at pressure differentials less than such predetermined value is effective to close said bleed orifice for continued movement of said control piston in displacement increasing direction.
Claim 29
Dependent Claim
94 words
The system of claim 1 wherein one of said pressure compensating members constitutes a load check valve downstream of the variable area orifice set by its associated valve member, and provides such additional restriction downstream of the variable area orifice set by its associated valve member; and wherein the other of said pressure compensating members constitutes a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths to and from the associated fluid motor, and provides such additional restriction in the return flow path from its associated fluid motor.
Claim 30
Dependent Claim
47 words
The system of claim 1 wherein one of said pressure compensating members constitutes a load check valve in series with the variable area orifice set by its associated valve member, and provides such additional restriction in series with the variable area orifice of its associated valve member.
Claim 31
Dependent Claim
27 words
The system of claim 29 wherein the other of said pressure compensating members provides such additional restrictiOn in the return flow path from its associated fluid motor.
Claim 32
Dependent Claim
62 words
The system of claim 1 wherein one of said pressure compensating members constitutes a load check valve downstream of the variable area orifice set by its associated valve member; and wherein another one of said pressure compensating members constitutes a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths to and from the associated fluid motor.
Claim 33
Dependent Claim
59 words
The system of claim 1 wherein one of said pressure compensating members, when moved as aforesaid, provides such additional restriction downstream of the variable area orifice set by its associated valve member; and wherein another one of said pressure compensating members, when moved as aforesaid, provides such additional restriction in the return flow path from its associated fluid motor.
Claim 34
Dependent Claim
104 words
The system of claim 1 wherein one of said valve members is of three way type defining another variable area orifice in the return path of flow from its associated single acting fluid motor; the associated pressure compensating member sensing the pressure drop across said another variable area orifice and being moved by increase of the latter above a predetermined value to provide additional restriction in the return flow path thus to maintain predetermined return flow as set by said another variable area orifice; and wherein said directional control valve has a load check valve downstream of another one of said pressure compensating members.
Claim 35
Dependent Claim
172 words
The system of claim 1 wherein one of said pressure compensating members is a spring biased spool-like member axially movable in a bore in said directional control valve and having a first land constituting a load check valve downstream of the variable area orifice set by its associated valve member, and having a second land provided with metering slots defining such additional restriction downstream of the variable area orifice set by its associated valve member; and wherein another one of said pressure compensating members is a spring biased spool-like member axially movable in a bore in said directional control valve and having a first land constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths acting on opposite ends of said spool-like member, and having a second land provided with metering slots defining such additional restriction in said return path, the ends of said spool-like member then being subjected to fluid pressure upstream and downstream of the variable area orifice of its associated valve member.
Claim 36
Dependent Claim
31 words
The system of claim 31 wherein yet another one of said pressure compensating members constitutes a load check valve upstream of the variable area orifice set by its associated valve member.
Claim 37
Dependent Claim
53 words
The system of claim 34 wherein yet another one of said pressure compensating members is a spring biased spool-like member which is axially movable in a bore in said directional control valve and which when moved as aforesaid, provides such additional restriction upstream of the variable area orifice of its associated valve member.
Claim 38
Dependent Claim
33 words
The system of claim 36 wherein said yet another one pressure compensating member, when moved as aforesaid, has its opposite ends respectively exposed to pressures upstream and downstream of said variable area orifice.
Claim 39
Dependent Claim
84 words
The system of claim 37 wherein said directional control valve has a spring biased pilot relief valve member therein which is exposed to downstream pressure acting on one end of said spool-like member of said yet another pressure compensating member and which is opened when such downstream pressure exceeds a predetermined value whereby upstream pressure acting on the other end of said spool-like member moves the latter to restrict flow through said additional restriction to the variable area orifice of its associated valve member.
Claim 40
Dependent Claim
81 words
The system of claim 31 wherein said sensing means comprises an unloading valve having a spring biased unloading valvE member movable in a bore in said directional control valve; said unloading valve member having its opposite ends respectively exposed to fluid pressure upstream of said variable area orifices and downstream of said check valves and being moved by the pressure differential acting on said ends exceeding a predetermined value to bypass excess flow from said pump means to said return port.
Claim 41
Dependent Claim
77 words
The system of claim 39 wherein said directional control valve has orifice means communicating said downstream pressure with said return port to retain said downstream pressure at low value when said valve members are in inactive position closing said variable area orifices; said orifice means being saturated upon actuation of either or both of said valve members to establish said variable area orifice or orifices for buildup of downstream pressure for control of said unloading valve member.
Claim 42
Dependent Claim
17 words
The system of claim 40 wherein said orifice means comprises a passage in said unloading valve member.
Claim 43
Dependent Claim
29 words
The system of claim 39 wherein said unloading valve member is a spool-like member having a groove and metering slots in the adjacent land for metering such excess flow.
Claim 44
Dependent Claim
52 words
The system of claim 31 wherein said pump means comprises a variable displacement pump; and wherein said sensing means comprises a pump output adjustment means responding to the pressure drop across said variable area orifices to adjust the output of said pump according to the flow demands set by said valve members.
Claim 45
Dependent Claim
142 words
The system of claim 43 wherein said pump output adjustment means comprises a movable displacement varying member; a spring and fluid pressure actuated control piston effective to move said displacement varying member in displacement increasing direction or to permit the latter to move in displacement decreasing direction; a main spring biased controller actuated by pump delivery pressure to apply force through spring means on said control piston in displacement increasing direction and to conduct upstream pressure to act on said control piston; an auxiliary spring biased controller exposed to fluid pressure upstream and downstream of said variable area orifices and operative upon the differential of said upstream and downstream pressures exceeding a predetermined value, to open a bleed orifice from said control piston to the intake side of said pump thus to discontinue movement of said displacement member in displacement increasing direction.
Claim 46
Dependent Claim
32 words
The system of claim 44 wherein said upstream pressure is derived from the delivery side of said pump, and said downstream pressure is derived from a passage in said directional control valve.
Claim 47
Dependent Claim
21 words
The system of claim 44 wherein said upstream and downstream pressures are derived from respective passages in said directional control valve.
Claim 48
Dependent Claim
40 words
The system of claim 44 wherein another spring means acts on said control piston at zero displacement position of said displacement varying member to provide for movement of said control piston in displacement increasing direction when said pump is started.
Claim 49
Dependent Claim
31 words
The system of claim 44 wherein said main controller, upon predetermined movement in displacement increasing direction opens another bleed orifice from said control piston to the intake side of said pump.
Claim 50
Dependent Claim
35 words
The system of claim 44 wherein said auxiliary controller at pressure differentials less than such predetermined value is effective to close said bleed orifice for continued movement of said control piston in displacement increasing direction.
Claim 51
Dependent Claim
81 words
The system of claim 35 wherein said sensing means comprises an unloading valve having a spring biased unloading valve member movable in a bore in said directional control valve; said unloading valve member having its opposite ends respectively exposed to fluid pressure upstream of said variable area orifices and downstream of said check valves and being moved by the pressure differential acting on said ends exceeding a predetermined value to bypass excess flow from said pump means to said return pOrt.
Claim 52
Dependent Claim
77 words
The system of claim 50 wherein said directional control valve has orifice means communicating said downstream pressure with said return port to retain said downstream pressure at low value when said valve members are in inactive position closing said variable area orifices; said orifice means being saturated upon actuation of either or both of said valve members to establish said variable area orifice or orifices for buildup of downstream pressure for control of said unloading valve member.
Claim 53
Dependent Claim
17 words
The system of claim 51 wherein said orifice means comprises a passage in said unloading valve member.
Claim 54
Dependent Claim
29 words
The system of claim 50 wherein said unloading valve member is a spool-like member having a groove and metering slots in the adjacent land for metering such excess flow.
Claim 55
Dependent Claim
52 words
The system of claim 35 wherein said pump means comprises a variable displacement pump; and wherein said sensing means comprises a pump output adjustment means responding to the pressure drop across said variable area orifices to adjust the output of said pump according to the flow demands set by said valve members.
Claim 56
Dependent Claim
142 words
The system of claim 54 wherein said pump output adjustment means comprises a movable displacement varying member; a spring and fluid pressure actuated control piston effective to move said displacement varying member in displacement increasing direction or to permit the latter to move in displacement decreasing direction; a main spring biased controller actuated by pump delivery pressure to apply force through spring means on said control piston in displacement increasing direction and to conduct upstream pressure to act on said control piston; an auxiliary spring biased controller exposed to fluid pressure upstream and downstream of said variable area orifices and operative upon the differential of said upstream and downstream pressures exceeding a predetermined value, to open a bleed orifice from said control piston to the intake side of said pump thus to discontinue movement of said displacement member in displacement increasing direction.
Claim 57
Dependent Claim
32 words
The system of claim 55 wherein said upstream pressure is derived from the delivery side of said pump, and said downstream pressure is derived from a passage in said directional control valve.
Claim 58
Dependent Claim
21 words
The system of claim 55 wherein said upstream and downstream pressures are derived from respective passages in said directional control valve.
Claim 59
Dependent Claim
40 words
The system of claim 55 wherein another spring means acts on said control piston at zero displacement position of said displacement varying member to provide for movement of said control piston in displacement increasing direction when said pump is started.
Claim 60
Dependent Claim
31 words
The system of claim 55 wherein said main controller, upon predetermined movement in displacement increasing direction opens another bleed orifice from said control piston to the intake side of said pump.
Claim 61
Dependent Claim
35 words
The system of claim 55 wherein said auxiliary controller at pressure differentials less than such predetermined value is effective to close said bleed orifice for continued movement of said control piston in displacement increasing direction.
Claim 62
Dependent Claim
97 words
The system of claim 31 wherein said directional control valve has a pilot operated relief valve comprising a spring biased pilot relief member which is exposed to fluid pressure downstream of one variable area orifice and upstream of its associated check valve and which is opened upon such fluid pressure exceeding a predetermined value, and a spring biased main valve member which provides a flow path to said sensing means via said variable area orifices and check valves and which is fluid pressure actuated to restrict said flow path when said pilot relief valve member is opened.
Claim 63
Dependent Claim
83 words
The system of claim 61 wherein said main valve member is axially reciprocable in a bore in said directional control valve and has one end exposed to such fluid pressure and the other end exposed to such fluid pressure via orifice means; the opening of said pilot relief valve member effecting reDuction of fluid pressure acting on said other end relative to fluid pressure acting on said one end whereby said main valve member is moved to restrict said flow path as aforesaid.
Claim 64
Dependent Claim
46 words
The system of claim 62 wherein said main valve member is a spool-like member having a groove providing said flow path and an adjacent land to restrict said flow path when said main valve member is moved by predominant fluid pressure acting on said one end.
Claim 65
Dependent Claim
97 words
The system of claim 35 wherein said directional control valve has a pilot operated relief valve comprising a spring biased pilot relief member which is exposed to fluid pressure downstream of one variable area orifice and upstream of its associated check valve and which is opened upon such fluid pressure exceeding a predetermined value, and a spring biased main valve member which provides a flow path to said sensing means via said variable area orifices and check valves and which is fluid pressure actuated to restrict said flow path when said pilot relief valve member is opened.
Claim 66
Dependent Claim
83 words
The system of claim 64 wherein said main valve member is axially reciprocable in a bore in said directional control valve and has one end exposed to such fluid pressure and the other end exposed to such fluid pressure via orifice means; the opening of said pilot relief valve member effecting reduction of fluid pressure acting on said other end relative to fluid pressure acting on said one end whereby said main valve member is moved to restrict said flow path as aforesaid.
Claim 67
Dependent Claim
46 words
The system of claim 65 wherein said main valve member is a spool-like member having a groove providing said flow path and an adjacent land to restrict said flow path when said main valve member is moved by predominant fluid pressure acting on said one end.
Claim 68
Dependent Claim
172 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve downstream of said variable area orifice; the movement of said compensating member providing such additional restriction downstream of said variable area orifice.
Claim 69
Dependent Claim
172 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve downstream of said variable area orifice; the movement of said compensating member providing such additional restriction downstream of said variable area orifice.
Claim 70
Dependent Claim
231 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve downstream of said variable area orifice; said valve member being of the three way type defining another variable area orifice in the return path of flow between said motor and return ports; said compensating member sensing the pressure drop across said another variable area orifice and being moved by increase of the latter above a predetermined value to provide additional restriction in the return flow path thus to maintain predetermined return flow as set by said another variable area orifice.
Claim 71
Dependent Claim
231 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve downstream of said variable area orifice; said valve member being of the three way type defining another variable area orifice in the return path of flow between said motor and return ports; said compensating member sensing the pressure drop across said another variable area orifice and being moved by increase of the latter above a predetermined value to provide additional restriction in the return flow path thus to maintain predetermined return flow as set by said another variable area orifice.
Claim 72
Dependent Claim
193 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve downstream of said variable area orifice; said compensating member having a first land constituting said load check valve and a second land provided with metering slots defining such additional restriction downstream of the variable area orifice set by its associated valve member.
Claim 73
Dependent Claim
193 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve downstream of said variable area orifice; said compensating member having a first land constituting said load check valve and a second land provided with metering slots defining such additional restriction downstream of the variable area orifice set by its associated valve member.
Claim 74
Dependent Claim
184 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid restriction in the return path of fluid flow to maintain the flow demand set by said variable area orifice; said compensating member constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths of fluid flow to and from a double acting fluid motor adapted to be connected to said motor ports; said housing having at least one load check valve downstream of said compensating member.
Claim 75
Dependent Claim
184 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid restriction in the return path of fluid flow to maintain the flow demand set by said variable area orifice; said compensating member constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths of fluid flow to and from a double acting fluid motor adapted to be connected to said motor ports; said housing having at least one load check valve downstream of said compensating member.
Claim 76
Dependent Claim
218 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively, a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid restriction in the return path of fluid flow to maintain the flow demand set by said variable area orifice; said compensating member constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths of fluid flow to and from a double acting fluid motor adapted to be connected to said motor ports; said housing having load check valves in passages leading to said motor ports downstream of said compensating member; said housing also having bypass passages to bypass the respective load check valves for return fluid flow from the respective motor porst to said return port via said valve member.
Claim 77
Dependent Claim
218 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively, a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid restriction in the return path of fluid flow to maintain the flow demand set by said variable area orifice; said compensating member constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths of fluid flow to and from a double acting fluid motor adapted to be connected to said motor ports; said housing having load check valves in passages leading to said motor ports downstream of said compensating member; said housing also having bypass passages to bypass the respective load check valves for return fluid flow from the respective motor porst to said return port via said valve member.
Claim 78
Dependent Claim
239 words
A pressure compensated directional control valve for an integrated Pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid restriction in the return path of fluid flow to maintain the flow demand set by said variable area orifice; said compensating member constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths of fluid flow to and from a double acting fluid motor adapted to be connected to said motor ports; said compensating member having a first land constituting said counter-balance valve which is opened by predetermined pressure differential in the supply and return paths acting on opposite ends of said compensating member, and having a second land provided with metering slots defining such additional restriction in said return path, the ends of said compensating member then being subject to fluid pressure upstream and downstream of said variable area orifice.
Claim 79
Dependent Claim
239 words
A pressure compensated directional control valve for an integrated Pressure compensated load sensing system and the like comprising a housing having inlet, motor, and return ports for connection with a fluid pressure source, a fluid motor, and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid restriction in the return path of fluid flow to maintain the flow demand set by said variable area orifice; said compensating member constituting a counterbalance valve which is opened by predetermined pressure differential in the supply and return paths of fluid flow to and from a double acting fluid motor adapted to be connected to said motor ports; said compensating member having a first land constituting said counter-balance valve which is opened by predetermined pressure differential in the supply and return paths acting on opposite ends of said compensating member, and having a second land provided with metering slots defining such additional restriction in said return path, the ends of said compensating member then being subject to fluid pressure upstream and downstream of said variable area orifice.
Claim 80
Dependent Claim
235 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motorm and return ports for connection with a fluid pressure source, a fluid motor and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve upstream of said variable area orifice; said compensating member providing such additional restriction upstream of said variable area orifice; and a spring biased pilot relief valve member in said housing exposed to downstream pressure acting on one end of said compensating member; said pilot relief valve member being opened when such downstream pressure exceeds a predetermined value whereby upstream pressure acting on the other end of said compensating member moves the latter to restrict flow through said additional restriction to said variable area orifice.
Claim 81
Dependent Claim
235 words
A pressure compensated directional control valve for an integrated pressure compensated load sensing system and the like comprising a housing having inlet, motorm and return ports for connection with a fluid pressure source, a fluid motor and a tank respectively; a spool valve member movable in a bore in said housing to control actuation of such fluid motor and to define a variable area orifice in the flow path of pressure fluid between said inlet and motor ports of size according to the extent of movement of said valve member; a spring biased spool-like pressure compensating member movable in another bore in said housing and having opposite end portions exposed to fluid pressure upstream and downstream of said variable area orifice to provide additional restriction in the supply path of pressure fluid to maintain the flow demand set by said variable area orifice; said compensating member constituting a load check valve upstream of said variable area orifice; said compensating member providing such additional restriction upstream of said variable area orifice; and a spring biased pilot relief valve member in said housing exposed to downstream pressure acting on one end of said compensating member; said pilot relief valve member being opened when such downstream pressure exceeds a predetermined value whereby upstream pressure acting on the other end of said compensating member moves the latter to restrict flow through said additional restriction to said variable area orifice.
Claim 82
Dependent Claim
167 words
An unloading valve for an integrated pressure compensated load sensing system and the like comprising a housing having a supply passage for flow of pressure fluid from a pump to a fluid motor via a variable area orifice in a directional control valve and a return passage leading to a tank; a spring biased spool-like unloading valve member movable in a bore in said housing and having its opposite ends respectively exposed to fluid pressure upstream and downstream of such variable area orifice; said unloading valve member being moved by the pressure differential acting on said ends exceeding a predetermined value to bypass excess flow from said supply passage to said return passage; and orifice means in said unloading valve communicating said downstream pressure with said return passage to retain said downstream pressure at low value when said variable area orifice is closed; said orifice means being saturated upon establishment of said variable area orifice for buildup of downstream pressure for control of said unloading valve member.
Claim 83
Dependent Claim
167 words
An unloading valve for an integrated pressure compensated load sensing system and the like comprising a housing having a supply passage for flow of pressure fluid from a pump to a fluid motor via a variable area orifice in a directional control valve and a return passage leading to a tank; a spring biased spool-like unloading valve member movable in a bore in said housing and having its opposite ends respectively exposed to fluid pressure upstream and downstream of such variable area orifice; said unloading valve member being moved by the pressure differential acting on said ends exceeding a predetermined value to bypass excess flow from said supply passage to said return passage; and orifice means in said unloading valve communicating said downstream pressure with said return passage to retain said downstream pressure at low value when said variable area orifice is closed; said orifice means being saturated upon establishment of said variable area orifice for buildup of downstream pressure for control of said unloading valve member.
Claim 84
Dependent Claim
18 words
The unloading valve of claim 74 wherein said Orifice means comprises a passage in said unloading valve member.
Claim 85
Dependent Claim
187 words
Output adjustment means for the variable displacement pump of an integrated pressure compensated load sensing system and the like, said output adjustment means responding to the pressure drop across a variable area orifice to adjust the output of said pump according to the flow demand set by said variable area orifice; said pump output adjustment means comprising a movable displacement varying member; a spring and fluid pressure actuated control piston effective to move said displacement varying member in displacement increasing direction or to permit the latter to move in displacement decreasing direction; a main spring biased controller actuated by pump delivery pressure to apply force through spring means on said control piston in displacement increasing direction and to conduct upstream pressure to act on said control piston; an auxiliary spring biased controller exposed to fluid pressure upstream and downstream of said variable area orifice and operative upon the differential of said upstream and downstream pressures exceeding a predetermined value, to open a bleed orifice from said control piston to the intake side of said pump thus to discontinue movement of said displacement member in displacement increasing direction.
Claim 86
Dependent Claim
187 words
Output adjustment means for the variable displacement pump of an integrated pressure compensated load sensing system and the like, said output adjustment means responding to the pressure drop across a variable area orifice to adjust the output of said pump according to the flow demand set by said variable area orifice; said pump output adjustment means comprising a movable displacement varying member; a spring and fluid pressure actuated control piston effective to move said displacement varying member in displacement increasing direction or to permit the latter to move in displacement decreasing direction; a main spring biased controller actuated by pump delivery pressure to apply force through spring means on said control piston in displacement increasing direction and to conduct upstream pressure to act on said control piston; an auxiliary spring biased controller exposed to fluid pressure upstream and downstream of said variable area orifice and operative upon the differential of said upstream and downstream pressures exceeding a predetermined value, to open a bleed orifice from said control piston to the intake side of said pump thus to discontinue movement of said displacement member in displacement increasing direction.
Claim 87
Dependent Claim
39 words
The output adjustment means of claim 76 wherein said upstream pressure is derived from the delivery side of said pump, and said downstream pressure is derived from a passage communicating with the dowstream side of said variable area orifice.
Claim 88
Dependent Claim
30 words
The output adjustment means of claim 76 wherein said upstream and downstream pressures are derived from respective passages communicating with the upstream and downstream sides of said variable area orifice.
Claim 89
Dependent Claim
42 words
The output adjustment means of claim 76 wherein another spring means acts on said control piston at zero displacement position of said displacement varying member to provide for movement of said control piston in displacement increasing direction when said pump is started.
Claim 90
Dependent Claim
33 words
The output adjustment means of claim 76 wherein said main controller, upon predetermined movement in displacement increasing direction opens another bleed orifice from said control piston to the intake side of said pump.
Claim 91
Dependent Claim
37 words
The output adjustment means of claim 76 wherein said auxiliary controller, at pressure differentials less than such predetermined value, is effective to close said bleed orifice for continued movement of said control piston in displacement increasing direction.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |