US3650425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bucket loader control system
Assignee: Vickers Inc
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Filing: 1970-06-12
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Granted: 1972-03-21
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Expires: 1990-06-12
Abstract
Abstract A material handling bucket loader with hydraulic boom lifting and bucket curling has an automatic control for bucket curling during the loading operation to assure filling of the bucket. The pressure developed in the boom lift system is utilized to open a normally closed curl valve when the load on the boom reaches a predetermined value which is manually adjustable. Manual override of the automatic curl valve is achieved by sensing the flow which occurs when the manual curl valve is operated and by shifting a shuttle valve in response to such flow.
Inventors
- 👤 Russell H Hallman
- 👤 John B Keir
- 👤 Lawrence J Patritto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:14
CPC Classifications
E; E02; E02F; E02F3/00; E02F3/04; E02F3/28; E02F3/36; E02F3/42; E02F3/43; E02F3/431; E02F3/434; F; F15; F15B; F15B11/00; F15B11/02; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/30; F15B2211/305; F15B2211/30505; F15B2211/30525; F15B2211/31; F15B2211/3105; F15B2211/3116; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50518; F15B2211/52; F15B2211/528; F15B2211/55; F15B2211/60; F15B2211/605; F15B2211/6051; F15B2211/635; F15B2211/6355; F15B2211/70; F15B2211/705; F15B2211/7051; F15B2211/7053; F15B2211/71; F15B2211/78; F15B2211/783
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
106 words
In a hydraulic control system for a bucket loader having a lift-lower valve with a cylinder controlled thereby to lift and lower the bucket, and a curl-dump valve with a cylinder controlled thereby to curl or dump the bucket, the improvement comprising an automatic normally closed curl valve connected in parallel with the curl-dump valve, means forming a pressure responsive actuator for the automatic curl valve, a connection from the lift-lower valve to that actuator for causing the bucket to curl automatically when the load to be lifted reaches the predetermined amount and means for disabling the automatic curl valve whenever the curl-dump valve is operated.
Claim 2
Dependent Claim
106 words
In a hydraulic control system for a bucket loader having a lift-lower valve with a cylinder controlled thereby to lift and lower the bucket, and a curl-dump valve with a cylinder controlled thereby to curl or dump the bucket, the improvement comprising an automatic normally closed curl valve connected in parallel with the curl-dump valve, means forming a pressure responsive actuator for the automatic curl valve, a connection from the lift-lower valve to that actuator for causing the bucket to curl automatically when the load to be lifted reaches the predetermined amount and means for disabling the automatic curl valve whenever the curl-dump valve is operated.
Claim 3
Dependent Claim
27 words
A system as defined in claim 1 wherein the last named means includes a shuttle valve responsive to flow to the bucket cylinder through the curl-dump valve.
Claim 4
Dependent Claim
40 words
A system as defined in claim 2 in which the curl-dump valve includes a check valve for preventing back flow from the bucket cylinder and the shuttle valve is connected to respond to the pressure drop across the check valve.
References Cited (Backward Citations)
US3494495A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |