US3645407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overload protector for crane booms
Assignee: Individual
•
Filing: 1970-06-15
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Granted: 1972-02-29
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Expires: 1990-06-15
Abstract
Abstract A vertically pivotable crane boom having a plurality of hydraulically extensible boom sections and equipped with a hydraulic lift cylinder for elevating and lowering the boom is provided with a plurality of stop devices automatically movable in response to an overload condition on the boom into blocking position adjacent hydraulic fluid control valves to prevent the manual operation of said valves in such a way as to extend the boom sections, lower the boom or hydraulically raise a lift cable on the boom. Hydraulic fluid from the boom lift cylinder is utilized to actuate a fluid motor which shifts the stop devices into said blocking position when the fluid pressure in said lift cylinder reaches a predetermined high level indicative of an overload condition on the boom.
Inventors
- 👤 Daniel F Przybylski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:47
CPC Classifications
B; B66; B66C; B66C23/00; B66C23/88; B66C23/90
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
234 words
In combination with a crane boom pivotally mounted at its base and equipped with a hydraulic motor for elevating said boom to different angular positions in a vertical plane, improved overload control apparatus comprising: a hydraulic circuit including a boom-elevating control valve in fluid flow communication with said hydraulic motor and operable to direct the flow of hydraulic fluid to said motor through alternate flow paths to effect either the elevating or lowering of said boom; a movable stop device disposed in cooperative association with said control valve; a fluid motor in fluid flow communication with said hydraulic motor for elevating said boom to different angular positions, whereby said hydraulic motor serves as a source of pressurized fluid for said fluid motor, said fluid motor being connected to said stop device for movement thereof to an overload position wherein said stop device prevents the operation of said control valve to lower said boom; and control means in the form of a valve in a fluid line between said hydraulic motor and said fluid motor, said valve being automatically operable in response to the attainment of a predetermined pressure level by the fluid in said hydraulic motor indicative of an overload condition on said boom to open said fluid line and permit the flow of pressurized hydraulic fluid to said fluid motor to thereby cause the actuation of said stop device to said overload position.
Claim 2
Dependent Claim
234 words
In combination with a crane boom pivotally mounted at its base and equipped with a hydraulic motor for elevating said boom to different angular positions in a vertical plane, improved overload control apparatus comprising: a hydraulic circuit including a boom-elevating control valve in fluid flow communication with said hydraulic motor and operable to direct the flow of hydraulic fluid to said motor through alternate flow paths to effect either the elevating or lowering of said boom; a movable stop device disposed in cooperative association with said control valve; a fluid motor in fluid flow communication with said hydraulic motor for elevating said boom to different angular positions, whereby said hydraulic motor serves as a source of pressurized fluid for said fluid motor, said fluid motor being connected to said stop device for movement thereof to an overload position wherein said stop device prevents the operation of said control valve to lower said boom; and control means in the form of a valve in a fluid line between said hydraulic motor and said fluid motor, said valve being automatically operable in response to the attainment of a predetermined pressure level by the fluid in said hydraulic motor indicative of an overload condition on said boom to open said fluid line and permit the flow of pressurized hydraulic fluid to said fluid motor to thereby cause the actuation of said stop device to said overload position.
Claim 3
Dependent Claim
115 words
A boom and overload control apparatus as defined in claim 1, and further including: a load lift cable on said boom operated by a winch driven by a second hydraulic motor; a second, winch control valve in said hydraulic circuit in fluid flow communication with said second hydraulic motor and operable to selectively direct the flow of hydraulic fluid to said second hydraulic motor to effect either the raising or lowering of said lift cable; a second stop device disposed in cooperative association with said second, winch control valve and connected to said motor for movement thereby to an overload position preventing the operation of said second, winch control valve to raise said lift cable.
Claim 4
Dependent Claim
125 words
A boom and overload control apparatus as defined in claim 2 wherein: said boom is comprised of a plurality of extensible aNd retractable boom sections operatively associated with a third hydraulic motor for extending and retracting movement thereof, and further including; a third, boom extension control valve connected in fluid flow communication with said third hydraulic motor and operable to selectively direct the flow of hydraulic fluid through alternate flow paths to effect either the extension or retraction of said boom sections; and a third stop device disposed in cooperative association with said third, boom extension control valve and connected to said fluid motor for movement thereby to an overload position preventing the operation of said third, boom extension control valve to extend boom sections.
Claim 5
Dependent Claim
72 words
A boom and overload control apparatus as defined in claim 2 wherein: each of said first and second control valves is operated by a lever mechanism having a portion thereof constructed and arranged for cooperative engagement with said stop devices, said first and second stop devices being so connected to said fluid motor as to be simultaneously shiftable thereby to said overload positions when said boom is subjected to said overload condition.
Claim 6
Dependent Claim
79 words
A boom and overload control apparatus as defined in claim 4 wherein: each of said stop devices is adjustable with respect to said portions of said lever mechanisms, whereby said stop devices may be adjusted to thereby insure that they will be properly disposed in said overload positions when moved by said fluid motor to prevent the movement of said valve lever mechanisms in such a direction as to either lower said boom or to raise said lift cable.
Claim 7
Dependent Claim
154 words
Overload control apparatus for a vertically pivotable crane boom having a lift cable operated by a winch driven by a hydraulic motor, comprising: a control valve connected in a hydraulic circuit with said hydraulic motor, said control valve being shiftable between a first, cable-raising position and a second, cable-lowering position in which it operates to direct pressurized hydraulic fluid to said hydraulic motor through alternate flow paths to alternately raise and lower said lift cable; a movable stop device disposed in cooperative relation to said control valve and movable into an overload position blocking the shifting of said control valve to said first position; motor means operatively associated with said stop device and operative to move said stop device to said overload position; and control means automatically operable in response to a predetermined overload condition on said crane boom to actuate said motor means and thereby move said stop device to said overload position.
Claim 8
Dependent Claim
154 words
Overload control apparatus for a vertically pivotable crane boom having a lift cable operated by a winch driven by a hydraulic motor, comprising: a control valve connected in a hydraulic circuit with said hydraulic motor, said control valve being shiftable between a first, cable-raising position and a second, cable-lowering position in which it operates to direct pressurized hydraulic fluid to said hydraulic motor through alternate flow paths to alternately raise and lower said lift cable; a movable stop device disposed in cooperative relation to said control valve and movable into an overload position blocking the shifting of said control valve to said first position; motor means operatively associated with said stop device and operative to move said stop device to said overload position; and control means automatically operable in response to a predetermined overload condition on said crane boom to actuate said motor means and thereby move said stop device to said overload position.
Claim 9
Dependent Claim
140 words
Overload control apparatus for a crane boom as defined in claim 6 wherein: said motor means comprises a hydraulic cylinder and piston assembly; said crane boom is vertically pivotable by means of a hydraulic lift motor having extensible means for elevating and lowering said boom in a vertical plane, the raising of the hydraulic pressure in said hydraulic motor to a predetermined level being indicative of an overload condition on said crane boom; and said control means includes, a fluid line connecting said hydraulic lift motor with said hydraulic cylinder and piston assembly and a valve in said fluid line, said valve being automatically operative in response to the attainment of said predetermined pressure level in said hydraulic lift motor to direct hydraulic fluid from said hydraulic lift motor to said hydraulic cylinder and piston assembly for the actuation thereof.
Claim 10
Dependent Claim
98 words
Overload control apparatus for a crane boom as defined in claim 7 wherein: said valve is a solenoid valve normally blocking flow through said fluid line to said hydraulic cylinder and piston assembly when it is energized, and shiftable by spring pressure to open said flow line when deenergized; and said control means further includes a pressure switch electrically connected to said solenoid valve and automatically responsive to the attainment of said predeterminEd pressure level in said hydraulic lift motor to open the electrical circuit to said solenoid valve, thereby deenergizing said valve and opening said fluid line.
Claim 11
Dependent Claim
85 words
Overload control apparatus as defined in claim 7 and further including: a second control valve in said hydraulic circuit for selectively directing the flow of hydraulic fluid to said hydraulic lift motor for either boom-elevating or boom-lowering operation; a second stop device disposed in cooperative relation to said second control valve and movable by said hydraulic cylinder and piston assembly to an overload position blocking the movement of said second control valve to a position permitting the boom lowering operation of said hydraulic lift motor.
References Cited (Backward Citations)
US3489294A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |