Crane with an erecting trestle

Abstract

The present invention relates to a crane, in particular a deck crane, which comprises a boom which is erectable in its height about an axis of rotation, and an erecting trestle for deflecting a rope of a retracting mechanism in order to erect the boom. The invention is characterized in that the erecting trestle is erectable in its height, and the erecting trestle comprises a pull bar which includes a rotary joint in order to rotate a first portion of the pull bar with respect to a second portion of the pull bar.

Claims

1. A crane, comprising: a boom which is vertically erectable about an axis of rotation, and an erecting trestle for deflecting a rope of a retracting mechanism in order to erect the boom, wherein the erecting trestle is vertically erectable, and the erecting trestle comprises a pull bar which includes a rotary joint spanned by hydraulic cylinders in order to rotate a first portion of the pull bar with respect to a second portion of the pull bar.

2. The crane according to claim 1, wherein the rotary joint of the pull bar can be locked in order to fix the erecting trestle in an erected position, wherein locking of the rotary joint is effected via a hydraulic cylinder.

3. The crane according to claim 1, wherein the crane is designed to lower the erecting trestle via an actuation of the retracting mechanism when the boom is deposited, the erecting trestle is erect and the rotary joint is unlocked, wherein during lowering the erecting trestle is supported on an inherent mass of the deposited boom and/or is lowered in a direction opposite to the boom.

4. The crane according to claim 3, wherein the rotary joint of the pull bar includes a mechanical stop in order to prevent the pull bar from being deposited in the direction of the boom.

5. The crane according to claim 1, wherein the rotary joint is a hinge joint, whose axis of rotation is parallel to the axis of rotation of the boom.

6. The crane according to claim 1, wherein the boom and the erecting trestle can be deposited in mutually opposite directions.

7. The crane according to claim 1, further comprising a crane base from which the boom and the erecting trestle extend and on which the retracting mechanism is arranged.

8. The crane according to claim 1, wherein a distal end region of the erecting trestle includes a deflection pulley for guiding the rope of the retracting mechanism.

9. The crane according to claim 1, wherein a distal end region of the boom includes a deflection pulley for guiding the rope of the retracting mechanism.

10. The crane according to claim 1, wherein beside the pull bar the erecting trestle comprises a rigid rod-like element which in a deflecting region of the rope of the retracting mechanism is connected to the pull bar via a connecting rotary joint.

11. The crane according to claim 10, wherein the boom, the rigid rod-like element, and the pull bar, are each arranged on a crane base via an associated base rotary joint, wherein axes of rotation of the base rotary joints arranged on the crane base are arranged parallel to each other.

12. The crane according to claim 11, wherein an axis of rotation of the rotary joint, which divides the pull bar into two portions rotatable relative to each other, is parallel to the axes of rotation of the base rotary joints.

13. The crane according to claim 10, further comprising a storage winch for receiving a certain amount of rope length of the rope actuated by the retracting mechanism, wherein the storage winch is arranged on the erecting trestle on the pull bar or the rigid rod-like element.

14. The crane according to claim 1, further comprising a deposition point for supporting the deposited pull bar in a deposited position in order to relieve the retracting mechanism.

15. The crane according to claim 14, wherein depositing of the erecting trestle is effected by gravity, wherein the hydraulic cylinders present for locking the rotary joint support the deposition by a corresponding pretension.

16. The crane according to claim 1, wherein when in a completely erected position, the erecting trestle is directed slightly obliquely away from the boom in order to be folded down away from the boom, when the rotary joint of the pull bar is unlocked.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further features, details and advantages of the present invention will become apparent from the following description of Figures. In the drawing:

(2) FIG. 1: shows a schematic basic construction of the crane according to the invention with an erected erecting trestle,

(3) FIG. 2: shows a schematic basic construction of the crane according to the invention with a deposited erecting trestle, and

(4) FIG. 3: shows a schematic basic construction of the crane according to the invention, which illustrates both the erected and the deposited erecting trestle in a joint representation.

DETAILED DESCRIPTION

(5) FIG. 1 shows a schematic view of the crane 1 according to the invention. From a crane base 12 a boom 2 extends, which in FIG. 1 is shown in the state already deposited or lowered. The boom 2 is coupled with the crane base 12 via a base rotary joint 19 so that the boom 2 can be pivoted on this base rotary joint 19. The pivot axis 3 extends substantially perpendicularly to the longitudinal extension of the boom 2. The boom 2 including a possible load suspended on the boom 2 is held via the retracting mechanism 6. The load radius (i.e. the outreach of the crane 1) can changed by actuating the retracting mechanism 6. The geometry of the erecting trestle 4 is chosen such that an optimum of system forces is obtained via favorable lever ratios.

(6) At the end of the boom 2 remote from the crane base 12 a deflection pulley 14 is provided, which cooperates with a rope 5 extending obliquely upward therefrom. This rope 5 is guided over an erecting trestle 4 to a rope winch 5 (also: retracting mechanism) arranged on the crane base 12, so that with a rigid erecting trestle 4 a reduction of the rope length leads to an erection of the boom 2.

(7) In the present case, the erecting trestle 4 comprises a pull bar 7 and an optional further rod-like element 15 which can be of rigid design. At the respective ends facing the crane base 12, both the pull bar 7 and the rod-like element 15 include a base rotary joint 17, 18 which provides for a pivotal movement. The axes of rotation of the base rotary joints 17, 18 and 19 are parallel in the present case, wherein this need not be the case in principle for the invention. At their ends remote from the crane base 12, the pull bar 7 and the rod-like element 15 are connected to each other via a rotary joint 16 in the form of a hinge joint. Furthermore, the pull bar 7 is arranged at a greater distance from the boom 2 than the rod-like element 15, i.e. is offset to the rear with respect to the rod-like element 15.

(8) The pull bar 7 is not formed in one piece, but comprises two portions 9, 10 foldable relative to each other, which are movable or rotatable relative to each other via a rotary joint 8. Due to this rotary joint 8 it is possible to lower the erecting trestle 4 to the rear, i.e. away from the boom 2, in order to reduce the maximum height of the crane during a transport or the like.

(9) The erecting trestle 4 can integrate the retracting mechanism 6 of the boom 2, by means of which the boom angle can be adjusted. The boom 2 including the load is held via the retracting mechanism 6, and the load radius (outreach) can be changed via the actuation of the retracting mechanism 6.

(10) For depositing/folding the erecting trestle 4, the pull bar 7 has the additional rotary joint 8 by means of which two portions 9, 10 of the pull bar 7 can be rotated against each other. In crane operation, i.e. with an erected erecting trestle 4, this joint 8 is locked and ensures a straight alignment of the two portions 9, 10 constituting the pull bar 7. For depositing the erecting trestle 4, the joint 8 then is unlocked. Locking the joint is effected via one or more hydraulic cylinders 11. Folding the erecting trestle 4 chiefly or exclusively is effected via the retracting mechanism 6. As soon as the additional rotary joint 8 arranged in the pull bar 7 is unlocked, the entire mass of the erecting trestle 4 hangs only in the retracting mechanism 6. The retracting mechanism 6 is supported on the boom 2 or its inherent mass. Supporting can be effected by the boom weight or an additional boom lock (not shown). The position of the center of gravity of the erecting trestle 4 effects that the erecting trestle 4 is folded down to the rear. In the present case, the portion 9 of the pull bar 7 facing the crane base 12 rotates away from the boom in clockwise direction so that the tip area of the erecting trestle 4 facing away from the crane base 12 is lowered. With the aid of the hydraulic cylinders 11, which span the rotary joint 8, i.e. are arranged both on the one portion 9 and on the other portion 10 of the pull bar 7, this can contribute to the pull bar 7 being folded down in a controlled way.

(11) The lower portion 9 in general is rotated downwards to the rear by an angle in the range from about 140° to 170°, until the portion 9 rests on a deposition point 21 of the crane base 12.

(12) The lowering movement of the erecting trestle 4 in essence can be divided into two parts, wherein initially only the rotary joint 8 is transferred into an open position, which by simultaneously rotating the lower portion 9 downwards to the rear leads to lowering of the tip of the erecting trestle. In this phase, the upper portion 10 remains in about the same orientation, but of course follows in the shape of a circular arc which is specified by the rotation of the lower portion on the base rotary joint 18.

(13) When the rotary joint 8 is in its maximally open position (visible e.g. in FIG. 2), the entire arrangement of the two portions 9, 10 is rotated downwards to the rear about the base rotary joint 18 so that it ultimately reaches the position shown in FIG. 2.

(14) This procedure can additionally be supported by hydraulic cylinders 11 in the form of a pretension. The hydraulic cylinders also can ensure that the pull bar 7 is specifically transferred into a lowering movement. A forward deflection of the pull bar 7 is prevented by a mechanical stop 22. Furthermore, a forward deflection is inhibited by the inherent weight of the erecting trestle 4, as its components are arranged in such a way that in an unlocked state and with the addition of rope length the same is folded down to the rear.

(15) The depositing operation is limited by a shelf 21 (cf. FIG. 2) which receives the first portion 9 and/or the second portion 10 of the pull bar 7. The shelf can be designed such that even longer transits of the ship or of the vehicle accommodating the crane are possible. The retracting mechanism can be relieved, i.e. the retracting ropes are free of load.

(16) FIG. 3 shows the two different positions of the erecting trestle 4 achievable by means of the invention, wherein in firm, continuous lines the regular working position of the erecting trestle 4 is shown, whereas the position of the erecting trestle 4 folded down or folded is shown with broken lines.

(17) The height difference achievable with the invention is clearly visible so that the advantages possible therewith are easily comprehensible.

(18) Due to the different geometrical conditions both in the erected and in the deposited state, the depositing operation requires a correspondingly longer rope 5 (or ropes in retracting mechanisms with double winches). With an erected erecting trestle, the additional rope length is stored either on the retracting winch 6 or, as shown, on an optional additional storage winch 20.

(19) Hence, during the depositing operation it is possible to either unwind the required additional rope length directly from the retracting winch 6 or—when a storage winch 20 is present—initially transfer the required additional rope length from the storage winch 20 to the retracting winch 6 in order to then lower the erecting trestle 4 by actuating the retracting winch 6.

(20) The advantage of this system consists in that with an erected erecting trestle 4 the retracting winch 6 must move only so much rope 5 as is required for the active crane operation, which in turn has a positive influence on the winding behavior of the retracting winch 6. In the regular working mode, the rope winch 6 accordingly does not have to rotate the rope length required for depositing the erecting trestle, so that the efficiency of the rope winch 6 is improved.

(21) Only when actually considering to lower the erecting trestle 4, can some rope 5 be transferred from the storage winch 20 to the retracting winch 6 by a rope transfer operation. Without a change in position of any of the structural components of the crane 1, some rope 5 can be reeled off from the storage winch 20 at a certain speed and be wound up by the retracting winch 6 at the same speed.

(22) It is clear to the skilled person that the erecting trestle 4 can include a plurality of pull bars 7 of the aforementioned type. Thus, the side view of FIGS. 1-3 does not exclude that there is at least one further pull bar 7 and/or at least one further rod-like element 15, which are arranged offset in the width direction of the crane 1 (i.e. perpendicularly to the longitudinal extension of the boom 2). The plurality of pull bars 7 and/or the plurality of rod-like elements 15 can be connected to each other at a common tip area of the erecting trestle 4, wherein the fundamental principle of folding down the erecting trestle 4 is not impaired, however.

LIST OF REFERENCE NUMERALS

(23) 1 crane 2 boom 3 axis of rotation of the boom 4 erecting trestle 5 rope of the retracting mechanism 6 retracting mechanism 7 pull bar 8 rotary joint of the pull bar 9 first portion of the pull bar 10 second portion of the insert 11 hydraulic cylinders 12 crane base 13 deflection pulley of the erecting trestle 14 deflection pulley of the boom 15 rigid rod-like element 16 rotary connecting joint 17 base rotary joint of the rigid rod-like element 18 base rotary joint of the pull bar 19 base rotary joint of the boom 20 storage winch 21 deposition point 22 stop