US3035710A - Hydraulic whip drive for the overhang beam of a crane - Google Patents

Description

F. POHL May 22, 1962 HYDRAULIC WHIP DRIVE FOR THE OVERHANG BEAM OF' A CRANE Filed June 5, 1959 United States Patent Office 3,035,710 Patented May 22, 1962 3,035,710 HYDRAULIC WHIP DRIVE FQR THE OVERHANG BEAM F A CRANE Friedrich Pohl, Hamburg, Germany, assigner to Hydrostahlbau-Gesellschaft Wiese & C0., Hamburg, Germany Filed June 5, 1959, Ser. No. 818,417 Claims priority, application Germany June 11, 1958 6 Claims. (Cl. 212-8) The present invention relates to an overhang crane with hydraulic whip drive for the overhang beam.

It is the primary object of the present invention to secure the overhang beam against overload by further lowering the overhang beam under load when said overhang beam occupies its maximum working position.

It is also an object of the present invention so to design a crane of the type set forth in the preceding paragraph that the means for preventing an overload under the conditions set forth in the preceding paragraph can be made ineective whenever the overhang beam is to be lowered into a resting position as is customary with ship cranes.

These and other objects and -advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing diagrammatically illustrating a safety control circuit for the crane in conformity with the present invention.

The hydraulic whip drive for the overhang beam of a whipping crane is characterized in conformity with the present invention in that a shut-olf valve adapted to block the hydraulic drive system for the Whipping cylinder of the overhang beam in maximum working condition of the latter, and which is controlled by the whipping movement of the overhang beam, is arranged in the lifting conduit of the whipping cylinder, while a conduit bypassing the shut-off valve is provided with a check valve shutting off said conduit during the lowering of the overhang beam.

Referring now tothe drawing in detail, the hydraulic whip drive according to the invention for an overhang beam 1 comprises a tiltably journailed cylinder 2 having reciprocably mounted therein a piston 3 with connecting rod 4 the free end of which is pivotally connected to the overhang beam 1. For purposes of elevating the overhang beam 1, pressure fluid is conveyed by a pump 5 through conduit 6 and a control valve 7 to cylinder 2. Correspondingly, when the overhang beam 1 is to be lowered, pressure fluid from pump 5 is conveyed through the control valve 7 and conduit 8 to the cylinder 2. The control valve 7, which is operable by hand for controlling the elevating or lowering of the overhang beam l, communicates with the pressure side of pump 5 through a conduit 9 and `also communicates through a conduit 11 with a fluid reservoir 10 for the working fluid. The suction side of pump 5 communicates through a suction conduit 12 likewise with the reservoir 10. Control valve 7 in one shifted position connects pressure conduit 9 with conduit 8 while connecting exhaust conduit 11 with conduit 6 and in another shifted position of control valve 7, these connections are reversed.

interposed in conduit 6 is a shut-olf valve 13 the control element 13a of which is adapted to be actuated by a cam 14 which is connected to the overhang beam 1. More specifically, the cam 14 may form a part of the bearing eye 15 of the overhang beam 1 and is so arranged that it will close the shut-off valve 13 as soon as the overhang beam during its lowering movement, brought about by the supply of pressure uid through conduit 8 into cylinder 2, approaches the position of its maximum overhang. As a result of the closing of shut-olf valve 13, the path of the liquid owing from cylinder 2 through conduit 6 to control valve 7 will be closed olf. As a result thereof, the pressure developing in conduit 6 prevents the piston 3 from moving upwardly with regard to the drawing, i.e. in the direction for lowering the beam 1 further.

lf the overhang beam 1 is now to be elevated from this position, the control valve 7 is adjusted accordingly so that pressure uid is conveyed through conduit 6 to cylinder 2 while fluid below piston 3 may escape through conduit 8 and control valve 7 into the reservoir 10. This supply of pressure fluid through conduit 6 to cylinder 2 is made possible, even though the shut-olf valve 13 is held in its closing position by cam 14, in view of the fact that a conduit 16 is automatically made effective which by-passes that portion of conduit 6 which leads to the shut-od valve 13. Moreover, that portion of conduit 6 which is located between a check valve 18 and control valve 7 is provided with a check valve 17 which will open by the feeding pressure in line 9. As soon as the overhang beam 1 has been lifted to such an extent that cam 14 no longer closes shut-off valve 13, pressure fluid will then pass through valve 13 and conduit 6 to cylinder 2. The check valve 18 above referred to is l0- cated in conduit 6 and normally permits free ilow of fluid upwardly therethrough toward the right end of cylinder 2, but does not normally permit uid to ilow downwardly through conduit 6 away from cylinder 2. Fluid can thus freely be supplied to cylinder 2 to elevate beam 1 but the fluid in the right end of cylinder 2 is normally entrapped therein by check valve 18 to prevent beam 1 from dropping accidentally.

Check valve 18 is adapted for being pilot operated into open position to release fluid from the right end of cylinder 2 to permit lowering of beam 1 and this is accomplished by a conduit connected from the pilot of check valve 13 to conduit 8 so that whenever actuating pressure is developed in conduit 8 to drive piston 3 rightwardly in cylinder 2 to lower the beam, check valve 18 will be piloted open to release iluid from the right end of cylinder 2. It will be evident that the beam 1 is prevented from dropping because whenever the beam moves fast enough to reduce the pressure on the left `side of piston 3, the pressure will drop in conduit 8, thus releasing the pilot pressure from check valve 18 permitting this valve to close and to interrupt the downwardly movement of the beam.

A rsum of the operation is as follows:

OPERATION I. Elevation of the Overhang Beam For elevating the overhang beam, pump 5 conveys pressure uid through pressure-relief valve 23, conduit 9, control valve 7, conduit 6, shut-od valve 13, and control valve 18 to cylinder 2, while fluid is discharged from the cylinder through conduit 8, control valve 7, and conduit 11 back to reservoir lil.

Il. Lowering the Overhang Beam For lowering the overhang beam, pump 5 conveys pressure fluid through pressure relief Valve 23, conduit 9, control valve 7, conduit S to cylinder 2.

(A) Cam 14 is part of the bearing 15 of the overhang beam and, as the overhang beam reaches its maximum overhang position it actuates control-tip 13a of shut-olf valve 13 which, in turn, will close the fluid path from the right end of cylinder 2. The pressure developed in blocked off conduit 6 will prevent the piston 3 from further movement and thus prevent further lowering of the overhang beam.

For elevating the beam from its maximum overhang position the control valve 7 is shifted so that pressure iluid flows through conduit 6 to cylinder 2. The fluid under piston 3 may escape through return conduit 8 and control valve 7 and conduit 11 into fluid reservoir 1). Since shut-ofi valve 13 is closed, in order to allow the supply of pressure fluid to cylinder 2, valve 13 is made ineffective by by-pass conduit 16 incorporating checkV valve 17 which will open under yslightly raised pressure conditions in conduit 9 allowing a ilow of fluid to cylinder 2. When the beam raises so that cam 14 no longer closes shut-o valve 13, the pressure fluid can pass through valve 13 and conduit 6 to cylinder 2, and check valve 17 may close.

If it is desired to move the overhang beam 1 downwardly into its rest position indicated by the dot-dash line A, beyond its position of maximum overhang, a discharge conduit 19 communicating with the conduit 6 and also with the exhaust line 11 is opened by a manually adjustable valve 20. This bypasses control valve 18 and control valve 7. When the overhang beam 1 is lowered in this manner without any supply of pressure fluid from pump S, piston 3 Will takev in fluid from reservoir 10 through conduit 11 and through conduit 21 which bypasses the closed control valve 7 and communicates with conduit 8. Conduit 21 comprises a check valve 22 adapted to open in response to a suction effect in conduit 8 and closes in response to a pressure in conduit 8.

For purposes of safeguarding against any overload, the feeding conduit 9 of pump 5 has interposed therein a relief valve 23 adapted in response to a predetermined pressure at the pressure side of pump to establish communication with conduit 24 leading to the reservoir 10.

It is, of course, to be understood that the present invention is, by no means, limited to the particular construction shown in the drawing but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In a hydraulic circuit for a Whipping crane comprising a tiltable overhang beam: a hydraulically operable cylinder piston system pivotally connected to said overhang beam for lifting and lowering the same, a pressure iiuid delivery pump, control valve means movable selectively into a rst position or into a second position, first conduit means leading from the pressure side of said pump to said control valve means, a iiuid reservoir connected to the suction side of said pump, second conduit means leading from said uid reservoir to said control valve means, third conduit means leading from said control valve means to one side of said cylinder piston system and being adapted in response to the movement of said control valve means into said first position to convey pressure iluid from said pump to said cylinder piston system for elevating said overhang beam, said third conduit means also being adapted in response to the movement of said control valve means into said second position to release fluid from said cylinder piston system to lower said overhang beam, fourth conduit means leading from said control valve means to said cylinder piston system and adapted in response to the movement of said control valve means into said rst position to release fluid therefrom during the elevating operation of said overhang beam, said fourth conduit means also being adapted in response to the movement of said control valve means to said second position to convey pressure huid to said cylinder piston system to positively lower said overhang beam, shut-off valve means interposed in said third conduit means and occupying its Closing position in response to said overhang beam occupying its maximum overhang position thereby interrupting the discharge of Huid from said cylinder piston system through said third conduit means, by-pass conduit means by-passing said shut-oir" valve means, and check valve means interposed in said bypass conduit means and adapted to open in response to pressure fluid being conveyed from said pump to said third conduit means, said check valve means closing in response to fluid released from said cylinder piston system through said third conduit means and said control valve means while the latter occupies its second position.

2. An arrangement according to claim 1, in which said overhang beam has connected thereto means for engagement with said shut-ofi valve means to close the same in maximum overhang position of said overhang beam.

3. An arrangement according to claim l, in which said overhang beam is provided with a bearing eye having cam means connected thereto for engaging said shut-olf valve means and moving the same into closing position when said overhang beam moves into its maximum overhang position.

4. In a hydraulic circuit for a Whipping crane comprising a titltable overhanging beam: a hydraulically operable cylinder piston system pivotally connected to said overhang Abeam for lifting and lowering the same, a pressure fluid delivery pump, control valve means movable selectively into a first position or into a second position, first conduit means leading from the pressure side of said pump to said control valve means, a fluid reser- Voir connected to the suction side of said pump, second conduit means leading from said fluid reservoir to said control valve means, third conduit means leading from said control valve means to one side of said cylinder piston system `and being adapted in response to the movement of said control valve means into said first position to convey pressure fluid from said pump to said cylinder piston system for elevating said overhanging beam, said third conduit means also being adapted in response to the movement of said control valve means into said second position to release fluid from said cylinder piston system to lower said overhang beam, fourth conduit means leading from said control valve means to said cylinder piston system and adapted in response to the movement of said control valve means into said first position to release iiuid therefrom during the elevating operation of said overhang beam, said fourth conduit means also being adapted in response to the movement of said control valve means to said second position to convey pressure iiuid to said cylinder piston system to positively lower said overhang beam, shut-olf valve means interposed in said third conduit means and occupying its closing position in response to said overhang beam occupying its maximum overhang position thereby interrupting the discharge of fluid from said cylinder piston system through said third conduit means, by-pass conduit means by-passing said shut-off Valve means, check valve means interposed in said by-pass conduit means and adapted to open in response to pressure iluid being conveyed from said pump to said third conduit means, said check valve means closing in response to iluid released from said cylinder piston system through said third conduit means and said cont-rol Valve means while the latter occupies its second position, and additional check valve means arranged in said third conduit means and communicating with said fourth conduit means, said additional check valve means being responsive to the pressure in said fourth conduit means so as to move into open position thereby permitting the discharge of fluid from said cylinder piston system through said third conduit means to said uid reservoir.

5. In a hydraulic circuit for a whipping crane comprising a tiltable overhang beam: a hydraulically operable cylinder piston system pivotally connecte-d to said overhang beam for lifting and lowering the same, a pressure iiuid delivery pump, control valve means movable selectively into a rst position or into a second position, first conduit means leading from the pressure side Vof said pump to said control valve means, a iluid reservoir connected to the suction side of said pump, second conduit means leading from said iiuid reservoir to said control valve means, third conduit means leading from said control valve means to one side of said cylinder piston system and being adapted in response to the movement of said control valve means into said rst position to convey pressure iiuid from said pump to said cylinder piston system for elevating said overhang beam, said third conduit means also being adapted in response to the movement of said control valve means into said second position to release iuid from said cylinder piston system to lower said overhang Ibeam, fourth conduit means leading from said control valve means to said cylinder piston system and adapted in response to the movement of said control valve means into said fn'st position to release uid therefrom during the elevating operation of said overhang beam, said fourth conduit means also being adapted in response to the movement of said control valve means to said second position to convey pressure uid to said cylinder piston system to positively lower said overhang lbeam, shut-oli Valve means interposed in said third conduit means and occupying its closing position in response to said overhang beam occupying its maximum overhang position thereby interrupting the discharge of tiuid from said cylinder piston system through said third conduit means, first -by-pass conduit means bypassing said shut-oi Valve means and adapted to establish communication between said third conduit means Iand said reservoir, manually operable valve means interposed in said irst by-pass conduit means and normally interrupting said rst by-pass conduit means, said manually operable means being movable into an open position to make said first by-pass conduit means eiective for lowering said overhang beam beyond its maximum overhang position, second by-pass conduit means by-passing said shut-olf valve means, and check valve means interposed in said second by-pass means and adapted to open in response to pressure fluid being conveyed from said pump to said third conduit means, said check valve means closing in response to uid released from said cylinder piston system through said third conduit means and said control valve means while the latter occupies its second position.

6. A hydraulic circuit Iaccording to claim 1, which includes a -by-pass line interconnecting said second and fourth conduit means -while `by-passing said control Valve means, land additional check valve means interposed in said by-pass conduit means and adapted to move into open position in response to ia suction eect in said fourth conduit means.

References Cited in the tile of this patent UNITED STATES PATENTS 1,714,545 Burns May 28, 1929 1,775,435 Litchenberg Sept. 9, 1930 2,013,690 Lamond Sept. 18, 1935

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