Patent US3722707A successfully refreshed from Google Patents.
US3722707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic crane control to prevent uncontrolled falling of load
Assignee: HARMISCHFEGER CORP
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Filing: 1971-11-03
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Granted: 1973-03-27
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Expires: 1991-11-03
Abstract
Abstract A boom crane comprises a platform on which a vertically movable boom, a front hoist drum, a rear hoist drum, a boom hoist drum, swing drive and an engine are mounted. The platform is rotatable in either direction about a vertical axis. The boom can be raised or lowered about a horizontal axis by means of a boom hoist line on the boom hoist drum. The front and rear drums are operable alternately to hoist and lower loads on their respective hoist lines. The aforesaid functions are controlled by a hydraulic control system which includes various levers and pedals that control hydraulic valves to regulate pressurization of various hydraulic clutch and brake cylinders. The control system comprises a selectively operable ''''dead man'''' actuation control for the front hoist drum and another ''''dead man'''' actuation control for the rear hoist drum. When actuated, each ''''dead man'''' actuation control effects automatic braking of its associated drum to prevent its load from falling in the event the control lever for that drum is returned to its neutral position while a load is being hoisted or lowered by that drum, as in the case when the crane operator is incapacitated. The control system further comprises a dump valve which automatically depressurizes the hydraulic system, in the event the boom and hoist line hooks are raised beyond a predetermined point.
Inventors
- 👤 N Hedeen
- 👤 C Javenkoski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:16
CPC Classifications
B; B66; B66C; B66C13/00; B66C13/18; B66C23/00; B66C23/62; B66C23/72; B66C2700/00; B66C2700/03; B66C2700/0392; B66C2700/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
389 words
A control system for a crane having a boom, a boom hoist drum, at least one load hoist drum for controlling a load suspended from said boom, and a brake for said load hoist drum comprising: a boom hoist drum control member, a load hoist drum control member, a load hoist drum brake control member, each of said control members having a neutral position and each being movable therefrom to other positions to effect a control function, a source of pressurized hydraulic fluid, a return reservoir and individual hydraulic valves controlled by said control members, each valve having an engaged position wherein it is supplied with fluid from said source, a brake lock control member selectively movable to a position wherein it effects locking of said brake, said boom hoist drum control member being movable from neutral position to one position to engage a valve for a boom hoist clutch cylinder and to another position to engage a valve for a boom hoist planetary brake cylinder, said load hoist drum control member being movable from neutral position to one position to engage a valve for a load hoist clutch cylinder and to another position to engage a valve for a load hoist planetary brake cylinder, said load hoist drum brake control member being movable from neutral position to one position to engage a valve for a load hoist drum brake cylinder, said brake lock control member being movable to its said position to engage a valve for a load hoist drum brake lock cylinder, a dead-man control member selectively movable to a position wherein it effects locking of said brake in the event said load hoist drum control member is in neutral position, said dead-man control member being movable to one position to engage a valve for said brake lock cylinder, and a boom-control member actuable to a position by elevation of said boom to a predetermined point to render all of said control members ineffective, except said load hoist drum brake control member, said boom control member being movable to its said position to engage a valve for disconnecting from said fluid source and connecting to said reservoir said valves for said boom hoist clutch cylinder, said boom hoist planetary brake cylinder, said load hoist clutch cylinder, said load hoist planetary brake cylinder, and said brake lock cylinder.
Claim 2
Dependent Claim
389 words
A control system for a crane having a boom, a boom hoist drum, at least one load hoist drum for controlling a load suspended from said boom, and a brake for said load hoist drum comprising: a boom hoist drum control member, a load hoist drum control member, a load hoist drum brake control member, each of said control members having a neutral position and each being movable therefrom to other positions to effect a control function, a source of pressurized hydraulic fluid, a return reservoir and individual hydraulic valves controlled by said control members, each valve having an engaged position wherein it is supplied with fluid from said source, a brake lock control member selectively movable to a position wherein it effects locking of said brake, said boom hoist drum control member being movable from neutral position to one position to engage a valve for a boom hoist clutch cylinder and to another position to engage a valve for a boom hoist planetary brake cylinder, said load hoist drum control member being movable from neutral position to one position to engage a valve for a load hoist clutch cylinder and to another position to engage a valve for a load hoist planetary brake cylinder, said load hoist drum brake control member being movable from neutral position to one position to engage a valve for a load hoist drum brake cylinder, said brake lock control member being movable to its said position to engage a valve for a load hoist drum brake lock cylinder, a dead-man control member selectively movable to a position wherein it effects locking of said brake in the event said load hoist drum control member is in neutral position, said dead-man control member being movable to one position to engage a valve for said brake lock cylinder, and a boom-control member actuable to a position by elevation of said boom to a predetermined point to render all of said control members ineffective, except said load hoist drum brake control member, said boom control member being movable to its said position to engage a valve for disconnecting from said fluid source and connecting to said reservoir said valves for said boom hoist clutch cylinder, said boom hoist planetary brake cylinder, said load hoist clutch cylinder, said load hoist planetary brake cylinder, and said brake lock cylinder.
Claim 3
Dependent Claim
252 words
A control system for a crane having at least one load hoist drum for controlling a load suspended therefrom and a brake for said load hoist drum comprising: a load hoist drum control member, a load hoist drum brake control member, each of said control members having a neutral position and each being movable therefrom to at least one other position to effect a control function, a source of pressurized hydraulic fluid, a return reservoir and individual hydraulic valves controlled by said control members, each valve having an engaged position wherein it is supplied with fluid from said source, a brake lock control member selectively movable to a position wherein it effects locking of said brake, said load hoist drum control member being movable from neutral position to one position to engage a valve for a load hoist clutch cylinder and to another position to engage a valve for a load hoist planetary brake cylinder, said load hoist drum brake control member being movable from neutral position to one position to engage a valve for a load hoist drum brake cylinder, said brake lock control member being movable to its said position to engage a valve for a load hoist drum brake lock cylinder, AND a dead-man control member selectively movable to a position wherein it effects locking of said brake in the event said load hoist drum control member is in neutral position, said dead-man control member being movable to one position to engage a valve for said brake lock cylinder.
Claim 4
Dependent Claim
252 words
A control system for a crane having at least one load hoist drum for controlling a load suspended therefrom and a brake for said load hoist drum comprising: a load hoist drum control member, a load hoist drum brake control member, each of said control members having a neutral position and each being movable therefrom to at least one other position to effect a control function, a source of pressurized hydraulic fluid, a return reservoir and individual hydraulic valves controlled by said control members, each valve having an engaged position wherein it is supplied with fluid from said source, a brake lock control member selectively movable to a position wherein it effects locking of said brake, said load hoist drum control member being movable from neutral position to one position to engage a valve for a load hoist clutch cylinder and to another position to engage a valve for a load hoist planetary brake cylinder, said load hoist drum brake control member being movable from neutral position to one position to engage a valve for a load hoist drum brake cylinder, said brake lock control member being movable to its said position to engage a valve for a load hoist drum brake lock cylinder, AND a dead-man control member selectively movable to a position wherein it effects locking of said brake in the event said load hoist drum control member is in neutral position, said dead-man control member being movable to one position to engage a valve for said brake lock cylinder.
Claim 5
Dependent Claim
251 words
A control system for a crane having a boom, a boom hoist drum and at least one load hoist drum for controlling a load suspended from said boom comprising: a boom hoist drum control member, at least one load hoist drum control member, each of said control members having a neutral position and each being movable therefrom to other positions to effect a control function, a source of pressurized hydraulic fluid, a return reservoir and individual hydraulic valves controlled by said control members, each valve having an engaged position wherein it is supplied with fluid from said source, said boom hoist drum control member being movable from neutral position to one position to engage a valve for a boom hoist clutch cylinder and to another position to engage a valve for a boom hoist planetary brake cylinder, said load hoist drum control member being movable from neutral position to one position to engage a valve for a load hoist clutch cylinder and to another position to engage a valve for a load hoist planetary brake cylinder, and a boom-control member actuable to a position by elevation of said boom to a predetermined point to render all of said control members ineffective, said boom-control member being movable to its said position to engage a valve for disconnecting from said fluid source and connecting to said reservoir said valves for said boom hoist clutch cylinder, said boom hoist planetary brake cylinder, said load hoist clutch cylinder, and said load hoist planetary brake cylinder.
Claim 6
Dependent Claim
251 words
A control system for a crane having a boom, a boom hoist drum and at least one load hoist drum for controlling a load suspended from said boom comprising: a boom hoist drum control member, at least one load hoist drum control member, each of said control members having a neutral position and each being movable therefrom to other positions to effect a control function, a source of pressurized hydraulic fluid, a return reservoir and individual hydraulic valves controlled by said control members, each valve having an engaged position wherein it is supplied with fluid from said source, said boom hoist drum control member being movable from neutral position to one position to engage a valve for a boom hoist clutch cylinder and to another position to engage a valve for a boom hoist planetary brake cylinder, said load hoist drum control member being movable from neutral position to one position to engage a valve for a load hoist clutch cylinder and to another position to engage a valve for a load hoist planetary brake cylinder, and a boom-control member actuable to a position by elevation of said boom to a predetermined point to render all of said control members ineffective, said boom-control member being movable to its said position to engage a valve for disconnecting from said fluid source and connecting to said reservoir said valves for said boom hoist clutch cylinder, said boom hoist planetary brake cylinder, said load hoist clutch cylinder, and said load hoist planetary brake cylinder.
Claim 7
Dependent Claim
36 words
A hydraulic control system according to claim 1 wherein said boom-control member comprises a solenoid coil for operating its associated valve and a limit switch responsive to boom position for controlling energization of said solenoid coil.
Claim 8
Dependent Claim
27 words
A hydraulic control system according to claim 4 wherein said limit switch effects deenergization of said solenoid coil when said boom is hoisted to a predetermined position.
Claim 9
Dependent Claim
46 words
A hydraulic control system according to claim 1 wherein said valve engaged by said dead-man control member connects said brake lock cylinder through a shuttle valve to said valve for said load hoist planetary brake cylinder and to said valve for said load hoist drum clutch.
Claim 10
Dependent Claim
36 words
A hydraulic control system according to claim 3 wherein said boom-control member comprises a solenoid coil for operating its associated valve and a limit switch responsive to boom position for controlling energization of said solenoid coil.
Claim 11
Dependent Claim
27 words
A hydraulic control system according to claim 7 wherein said limit switch effects deenergization of said solenoid coil when said boom is hoisted to a predetermined position.
Claim 12
Dependent Claim
46 words
A hydraulic control system according to claim 2 wherein said valve engaged by said dead-man control member connects said brake lock cylinder through a shuttle valve to said valve for said load hoist planetary brake cylinder and to said valve for said load hoist drum clutch.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |