US3680723A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic control system for backhoes
Assignee: Case LLC
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Filing: 1971-02-18
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Granted: 1972-08-01
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Expires: 1991-02-18
Abstract
Abstract A hydraulic control system for controlling the pivotal movement of a swing tower of a backhoe and accurately positioning the swing tower in predetermined positions relative to a support. The hydraulic control circuit includes first and second valves disposed in parallel between a fluid motor, a reservoir and pressurized fluid source. The valve spools of the two valves are interconnected by a linkage which can be moved manually to simultaneously move both valves to an actuated position. Signal means cooperate with the swing tower and the linkage to sequentially neutralize the respective valves as the tower approaches a predetermined portion so that only one valve is in an actuated position when the swing tower is in close proximity to the predetermined position and can accurately position the tower.
Inventors
- 👤 David H Seaberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:49
CPC Classifications
E; E02; E02F; E02F3/00; E02F3/04; E02F3/28; E02F3/36; E02F3/38; E02F3/382; E02F3/384
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
139 words
In a backhoe having a tower pivoted about a fixed pivot axis on a support by a fluid motor interposed between said tower and said support, a hydraulic control system controlling the supply of fluid to said fluid motor and comprising a pressurized fluid source; a reservoir; conduit means connecting said source and reservoir to said fluid motor; valve means in said conduit means for controlling the flow of fluid to and from said motor; and manual means for actuating said valve means, the improvement of means for accurately positioning said tower in a predetermined position relative to said support, said last means including first and second valves defining said valve means and connected in parallel between said source and reservoir and said motor and actuating means responsive to pivotal movement of said tower for sequentially neutralizing said valves.
Claim 2
Dependent Claim
139 words
In a backhoe having a tower pivoted about a fixed pivot axis on a support by a fluid motor interposed between said tower and said support, a hydraulic control system controlling the supply of fluid to said fluid motor and comprising a pressurized fluid source; a reservoir; conduit means connecting said source and reservoir to said fluid motor; valve means in said conduit means for controlling the flow of fluid to and from said motor; and manual means for actuating said valve means, the improvement of means for accurately positioning said tower in a predetermined position relative to said support, said last means including first and second valves defining said valve means and connected in parallel between said source and reservoir and said motor and actuating means responsive to pivotal movement of said tower for sequentially neutralizing said valves.
Claim 3
Dependent Claim
37 words
A backhoe as defined in claim 1, in which said first valve has a flow capacity substantially greater than said second valve so that a majority of fluid supplied to said motor passes through said first valve.
Claim 4
Dependent Claim
46 words
A backhoe as defined in claim 1, in which said valves each have a valve spool movable in opposite directions from a neutral position, and said activating means includes linkage means interconnecting said spools for simultaneous movement with said manual means cooperating with said linkage means.
Claim 5
Dependent Claim
20 words
A backhoe as defined in claim 3, in which said linkage means includes adjustable means for varying said predetermined position.
Claim 6
Dependent Claim
34 words
A backhoe as defined in claim 3, and including sensing means connected to said tower and cooperating with said linkage means, and a lost motion connection between said sensing means and said linkage means.
Claim 7
Dependent Claim
60 words
A backhoe as defined in claim 3, in which said linkage means includes a lever pivoted intermediate its ends on said support adjacent said spools; first and second links respectively connecting opposite ends of said lever to the respective valve spools, said manual means cooperating with one of said links; and sensing means connected to the other of said links.
Claim 8
Dependent Claim
85 words
A backhoe as defined in claim 6, in which said other of said links has an elongated slot and said sensing means has an element in said slot moved in response to pivotal movement of said tower on said support; and adjustable means cooperating with one end of said slot and engaged by said element when said tower approaches said predetermineD position to move said linkage means and said valve spools to a neutral position, said adjustable means being capable of varying said predetermined position.
Claim 9
Dependent Claim
41 words
A backhoe as defined in claim 7, and further including elastic means between said manual means and said one of said links accommodating movement of said linkage means to said neutral position while said manual means is in an actuated position.
Claim 10
Dependent Claim
28 words
A backhoe as defined in claim 7, and including a second adjustable means cooperating with an opposite end of said slot to define a second variable predetermined position.
Claim 11
Dependent Claim
138 words
In combination with a backhoe having a swing tower pivoted about a vertical axis on a support by a fluid motor, a hydraulic control system including a pressurized fluid source; a reservoir; conduit means connecting said source and said reservoir to said fluid motor; valve means including first and second valve spools connected in parallel in said conduit means and movable in opposite directions from a neutral position; linkage means connected to said valve spools; manual means cooperating with said linkage means for actuating said spools in either direction from said neutral position and pivot said tower in opposite directions on said support; and sensing means connected to said tower and cooperating with said linkage means to sequentially move said valve spool to said neutral positions when said tower is in predetermined extreme pivoted positions on said support.
Claim 12
Dependent Claim
138 words
In combination with a backhoe having a swing tower pivoted about a vertical axis on a support by a fluid motor, a hydraulic control system including a pressurized fluid source; a reservoir; conduit means connecting said source and said reservoir to said fluid motor; valve means including first and second valve spools connected in parallel in said conduit means and movable in opposite directions from a neutral position; linkage means connected to said valve spools; manual means cooperating with said linkage means for actuating said spools in either direction from said neutral position and pivot said tower in opposite directions on said support; and sensing means connected to said tower and cooperating with said linkage means to sequentially move said valve spool to said neutral positions when said tower is in predetermined extreme pivoted positions on said support.
Claim 13
Dependent Claim
15 words
The combination as defined in claim 10, further including adjustable means for varying said positions.
Claim 14
Dependent Claim
37 words
The combination as defined in claim 11, in which said sensing means is connected to said linkage means by a lost motion connection to accommodate relative movement and said adjustable means varies the amount of relative movement.
Claim 15
Dependent Claim
62 words
The combination as defined in claim 12, further including means between said linkage means and said manual means (1) defining a fixed connection between said manual means and linkage means when said linkage means is moved by said manual means and (2) accommodating relative movement between said manual means and linkage means when said linkage means is moved by said sensing means.
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) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |