US3826328A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual hydraulic power steering system
Assignee: SHEPPARD R CO
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Filing: 1972-03-20
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Granted: 1974-07-30
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Expires: 1992-03-20
Abstract
Abstract Steering for wheels of a vehicle is provided by two separate and independent steering combinations of first and second power operating units, corresponding first and second power supply means and control means with each combination providing only approximately 50 percent of the total design force required to allow the operator of the vehicle to comfortably turn the wheels. The system thus is designed to provide a safety factor of allowing approximately one-half force power steering upon failure of one combination. With two operating units, one adjacent each wheel, a resilient interconnection in the tie rod of the steering linkage is required. In a tandem wheel arrangement, a steering gear or operating unit is provided on each axle. The preferred embodiment includes a master steering gear assembly on one side of the vehicle and a slave gear assembly on the other with two in-piston valves positioned in the master steering gear unit. The valves include spool elements that are both guided and maintained in alignment by a guide pin having three guide surfaces. Transfer of the fluid in the second combination includes telescoping tubes extending through and forming a seal with the passageway at tne end of the piston of the master unit. The two spool elements are accurately positioned during manufacture by interposed resilient means and radial locking pin arrangement.
Inventors
- 👤 R Sheppard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:30
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/30; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/8667; Y10T137/86694; Y10T137/8671
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
276 words
A failsafe dual hydraulic power steering system for coordinated wheels of a vehicle ultimately independent of hydraulics comprising first and second power operating units, steering linkage means provided between said wheels and said power operating units to interconnect the same, corresponding first and second power supply meAns interconnected to the corresponding operating units, synchronized first and second control means connected between the respective operating units and supply means to direct the flow of fluid as required to steer the vehicle, each combination of operating unit, control means and supply means being independent for directly turning separate wheels and each combination providing only approximately 50 percent of the total design force required to allow the operator of the vehicle to comfortably turn said wheels, said first and second control means includes a common steering input shaft for driver operation, at least one of said operating units comprising an integral power steering gear assembly to allow operation upon failure of said supply means including a reciprocating piston, integral valve means and rack, an output gear and crank, and said linkage means includes a drag link connected to said crank to transmit steering motion, interface means between said input shaft and said piston for direct non-hydraulic mechanical connection between said input shaft and said piston for manual steering upon failure of both units, said first and second power operating units and the associated steering linkage means tending to provide differential movement to steering of said wheels and compensating means for accommodating the difference, whereby both of said combinations may normally operate in said system and upon failure of one combination approximately one-half force power steering may still be effective.
Claim 2
Dependent Claim
276 words
A failsafe dual hydraulic power steering system for coordinated wheels of a vehicle ultimately independent of hydraulics comprising first and second power operating units, steering linkage means provided between said wheels and said power operating units to interconnect the same, corresponding first and second power supply meAns interconnected to the corresponding operating units, synchronized first and second control means connected between the respective operating units and supply means to direct the flow of fluid as required to steer the vehicle, each combination of operating unit, control means and supply means being independent for directly turning separate wheels and each combination providing only approximately 50 percent of the total design force required to allow the operator of the vehicle to comfortably turn said wheels, said first and second control means includes a common steering input shaft for driver operation, at least one of said operating units comprising an integral power steering gear assembly to allow operation upon failure of said supply means including a reciprocating piston, integral valve means and rack, an output gear and crank, and said linkage means includes a drag link connected to said crank to transmit steering motion, interface means between said input shaft and said piston for direct non-hydraulic mechanical connection between said input shaft and said piston for manual steering upon failure of both units, said first and second power operating units and the associated steering linkage means tending to provide differential movement to steering of said wheels and compensating means for accommodating the difference, whereby both of said combinations may normally operate in said system and upon failure of one combination approximately one-half force power steering may still be effective.
Claim 3
Dependent Claim
110 words
The system of claim 1 wherein said valve means includes a valve chamber, a first movable spool element in said chamber to regulate the flow to said first power operating means, a second movable spool valve element, guide pin in said piston, an axially extending guide slot in one of said spool elements, locking means to hold said spool elements together, parallel guide surfaces on said pin to fit in said slot to prevent the same from rotating, said guide pin having a radially inward guide surface acting on the outer face of said other spool element and cooperating with said locking means to maintain said spools in perfect alignment.
Claim 4
Dependent Claim
82 words
The system of claim 1 wherein said valve means includes a valve chamber, a first movable spool element in said chamber to regulate the flow to said first power operating means, a second movable spool valve element in said chamber, said valve chamber being within said piston, and fluid transfer means spaced from the central axis of said piston for said second operating means including telescoping tubes extending through and forming a seal with a passageway at the end of said piston.
Claim 5
Dependent Claim
33 words
The system of claim 1 wherein the total design force of said system allows steering with the application of approximately five foot pounds of input torque to the steering shaft of said vehicle.
Claim 6
Dependent Claim
59 words
The system of claim 1 wherein said steering linkage includes a tie rod to connect said wheels to turn together, a steering arm for said each combination, and said compensating means includes resilient means on said tie rod to compensate for said differential movement including that caused by variations in geometry of the steering linkage including said steering arms.
Claim 7
Dependent Claim
75 words
The system of claim 5 wherein said resilient means comprises a telescoping connection on said tie rod having inner and outer members, spaced first and second flange means around the periphery of the outer member and pin means through the inner member, slot means for movement of said pin means in said outer member in an axial direction and spring means held between said flanges and said pin means to provide resiliency in both directions.
Claim 8
Dependent Claim
81 words
The system of claim 1 wherein said valve means includes a valve chamber, a first movable spool element in said chamber to regulate the flow to said first power operating means, a second movable spool valve element held axially apart from said first element in said chamber by interposed resilient means, adjustable means at the end of said chamber to initially position said elements in synchronization with each other and locking means to fix said elements together in the adjusted position.
Claim 9
Dependent Claim
25 words
The system of claim 7 wherein said locking means includes holes drilled during assembly through said elements and radial pin means fixed in said holes.
Claim 10
Dependent Claim
44 words
The system of claim 8 wherein said one of said operating units includes in said valve means said spool elements located in the piston and radial access aperture in said piston to position said pin means after assembly of valve means in said piston.
Claim 11
Dependent Claim
65 words
The system of claim 8 wherein said pin means includes a pin provided on each of the opposite sides of said spool elements, and guide pin in said piston, an axially extending guide slot in one of said spool elements, locking means to hold said spool elements together, parallel guide surfaces on said pin to fit in said slot to prevent the same from rotating.
Claim 12
Dependent Claim
225 words
In a failsafe dual hydraulic power steering system untimately independent of hydraulics having master and slave power steering assemblies for wheels of a vehicle and steering linkage means provided between said wheels and said power steering assemblies to interconnect the same, the improvement of a master power steering gear assembly comprising a housing, a piston slidable in said housing to provide power steering force for said system, and a tandem valve for concurrently operating the master power steering assembly and the slave power steering assembly, said tandem valve including a first spool element for controlling the flow of fluid to said master assembly and a second spool element attached to said first spool element for controlling the fluid to the slave gear assembly, said spool elements being controlled by an input shaft by driver operation, said master steering assembly including interface means between said input shaft and said piston for direct non-hydraulic mechanical connection between said input shaft and said piston for manual steering upon failure of both assemblies, said first and second power steering assemblies and the associated steering linkage means tending to provide differential movement to steering of said wheels and compensating means for accomodating the difference, whereby both of said assemblies may normally operate in said system and only one control assembly is required for said master assembly and said slave assembly.
Claim 13
Dependent Claim
225 words
In a failsafe dual hydraulic power steering system untimately independent of hydraulics having master and slave power steering assemblies for wheels of a vehicle and steering linkage means provided between said wheels and said power steering assemblies to interconnect the same, the improvement of a master power steering gear assembly comprising a housing, a piston slidable in said housing to provide power steering force for said system, and a tandem valve for concurrently operating the master power steering assembly and the slave power steering assembly, said tandem valve including a first spool element for controlling the flow of fluid to said master assembly and a second spool element attached to said first spool element for controlling the fluid to the slave gear assembly, said spool elements being controlled by an input shaft by driver operation, said master steering assembly including interface means between said input shaft and said piston for direct non-hydraulic mechanical connection between said input shaft and said piston for manual steering upon failure of both assemblies, said first and second power steering assemblies and the associated steering linkage means tending to provide differential movement to steering of said wheels and compensating means for accomodating the difference, whereby both of said assemblies may normally operate in said system and only one control assembly is required for said master assembly and said slave assembly.
Claim 14
Dependent Claim
56 words
The dual hydraulic power steering system of claim 11 wherein is further provided means for transferring fluid between said second spool element and said slave gear assembly, said transfer means comprising telescoping tubes spaced from the central axis of said piston extending through and forming a seal with corresponding passageways at the end of said piston.
Claim 15
Dependent Claim
29 words
The dual hydraulic power steering system of claim 11 wherein said first spool element is attached to said second spool element by means of a radially extending pin means.
Claim 16
Dependent Claim
42 words
The dual hydraulic power steering system of claim 13 wherein is further provided an interposed spring between said first spool element and said second spool element to bias said elements apart until locking together the same with said pin means during assembly.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-29 | 1978-01-28 | 1978-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-29 | 1982-01-28 | 1982-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-29 | 1986-01-28 | 1986-07-30 | $7700.00 | Window Closed / Lapsed |