EP2248753A1 - Crane which can overcome dead centre - Google Patents

Abstract

The crane has two crane arms (11, 12) connected with each other by a hinge (14) and pivotable relative to each other by a drive having a piston-cylinder-unit (13). The crane arms reach a dead centre based on an end position when a longitudinal axis of the piston-cylinder-unit is preset in alignment with the hinge. The crane arms rest parallel to each other in the end position. Another drive i.e. linear drive, stands in effective-connection with one of the arms by a detachable coupling unit. A dead centre position of the piston-cylinder-unit to the hinge is conquerable by the latter drive.

Description

The invention relates to a crane, in particular a vehicle crane, with a first crane arm and at least one second crane arm, which are connected to one another via a joint and are pivotable relative to one another via a drive having a piston-cylinder unit, in each case starting from one of the two end positions which the crane arms are substantially parallel to each other until a dead center is reached when the longitudinal axis of the piston-cylinder unit is substantially in line with the hinge.

A common way to overcome the dead center of a piston-cylinder unit to the joint is that in which the crane arms are lifted with their load-carrying means against the ground. The occurring torque relative to the joint brings the piston-cylinder unit beyond the dead center and the crane can be folded. This method is extremely cost-effective, since no additional material expenditure is necessary. The disadvantage of this method is that the folding is thus relatively time-consuming and space-consuming, since the crane arms - in fact their load-carrying means - ground contact must be established while the two crane arms are unfolded. Often, such cranes are designed so that the drive not only has a piston-cylinder unit but for example, two parallel piston-cylinder units are used, the symmetrically move in the same direction, the two crane arms relative to each other. Here, the dead center of the two piston-cylinder units occurs at the same position of the joint, overcoming the dead center has to be done in the same manner as just described.

From the DE 69 16 283 is a pivot assembly for articulated boom is known, which has an intermediate member between the two crane arms and two attached to the crane arms and the intermediate member lifting cylinders. The entire pivoting angle is increased by the fact that a lifting cylinder is responsible for a pivoting range of about 160 degrees and the second lifting cylinder for a further additional pivoting range of about 120 degrees. Thus, it is avoided to have to overcome the dead center of a lifting cylinder, since neither of the two lifting cylinders must be extended to its dead center. As a result, the work areas are divided between the two lifting cylinders. The downside of this method is that it increases with Cost of materials and thus increased costs associated because an intermediate member and two powerful lifting cylinders are necessary to achieve a pivoting range of the two crane arms, which is greater than 180 degrees.

The object of the invention is to avoid the above-described disadvantages and to provide a comparison with the prior art improved crane, in which the dead center of the piston-cylinder unit is overcome to the joint.

This object is achieved in the crane according to the invention characterized in that at least one further drive is provided, through which the dead center of the piston-cylinder unit to the joint can be overcome.

In other words, this further drive causes a located in the dead center piston-cylinder unit - strictly speaking, the dead center occurs when the force vector of the piston-cylinder unit in line with the joint between the first crane arm and second Crane arm is - is freed from this dead center and thus again the piston-cylinder unit takes over the further pivoting of the two crane arms to each other. Thus, the pivoting of the two crane arms - apart from the area of the dead center - over the entire range of approximately 360 degrees with one and the same piston-cylinder unit. The further drive is required only in the dead center position of the two crane arms and thus only has to be designed so powerful that its force is sufficient to overcome the dead center. The further drive does not have to be carried out in order to pivot the two crane arms further, because after overcoming the dead center again the piston-cylinder unit takes over the pivoting, so you could view it as an auxiliary drive. The previous construction of a crane can - in contrast to that in the DE 69 16 283 crane are retained - there are no major modifications necessary, the crane arms are only additionally equipped with the further drive. It is thus also possible that existing cranes are retrofitted with such a further drive to overcome a dead center of the piston-cylinder unit. The space required during pivoting is minimized because no support of the folded crane arms on the ground is necessary and this can also be done in the raised state of the crane arms, which is especially in a small space - such as between houses, on construction sites and in the forest, etc. - a large Advantage is. It should be noted that it is of course also possible to design the piston-cylinder unit so that, for example, two essentially parallel piston-cylinder units are used, which move symmetrically in the same direction, the two crane arms relative to each other. By using a further drive, one is further not dependent on an additional joint or intermediate member between the two crane arms and the piston-cylinder unit to allow a pivoting beyond the dead center.

• Vorzugsweise umfasst der weitere Antrieb einen Linearantrieb, besonders vorteilhaft ist dabei wenn der Linearantrieb eine Kolben-Zylinder-Einheit aufweist, da diese sowohl eine kleine Bauform ermöglicht als auch gut gegen Umwelteinflüsse geschützt werden kann.

Further advantageous embodiments of the invention are defined in the dependent claims:

• Preferably, the further drive comprises a linear drive, it is particularly advantageous if the linear drive has a piston-cylinder unit, since this allows both a small design and can be well protected against environmental influences.

Preferably, the further drive is provided with a pulling means which extends from the bottom of the first crane arm on the hinge over to the top of the second crane arm and thereby enables a good power transmission in a small footprint. Also particularly advantageous here is a chain suitable as traction means, as well as belts, ropes and other movable traction means are of course possible.

According to a preferred embodiment, it can be provided to let the further drive act via a releasable coupling device, as this allows small sizes and thus the folding is not limited by rods, joints or the like. Thus, for example, the first coupling part as a catching device and the ge caught second coupling part may be formed on another drive. Preferably, the releasable coupling device can also be provided with a lever, as this allows an improved power transmission.

It has proven to be particularly advantageous if the further drive is performed inside one of the two crane arms, since there is thus no space requirement on the outside of one of the two crane arms, thus ensuring maximum collapsibility and space savings. Preferably, the crane arms are made telescopic, as this greater ranges can be achieved.

According to a preferred embodiment, it may be provided to equip the crane with a control device which triggers an automatic switching of the effective direction of the piston-cylinder unit and thus no manual switching is required. Preferably, this switching operation is performed by a switching device having a switching valve, which acts as a limit switch, which causes a reversal of the piston-cylinder unit at the switching point. As a switching device, of course, any other technical possibility can be taken into account, which can trigger a switching operation, such as a sensor or a photoelectric sensor or the like.

According to a preferred embodiment, it may be provided to arrange the further drive on the crane arm such that the dead center position of the piston-cylinder unit enters at a different joint position than the dead center position of the piston-cylinder unit of the further drive. Thus, it is possible that a piston-cylinder unit frees the other piston-cylinder unit from its dead center.

It has proven to be particularly advantageous if the piston-cylinder units of the drives are designed so that they are substantially equivalent and their arrangement is substantially parallel to each other on the sides of the first crane arm and asymmetrically on the sides of the second crane arm.

As a particularly suitable application can be provided to execute the crane as a Z-crane, which has a rotatably mounted vertical crane column, a hinged thereto and at least one articulated arm articulated to the lifting arm articulated. In the following, the lifting arm is referred to by way of example as a first crane arm and the articulated arm as a second crane arm, but this is not to be regarded as a restriction.

Fig. 1 bis 8

Ausführungsbeispiele einer erfindungsgemäßen Anordnung in 8 schematischen Ansichten,

Fig. 9 bis 11

schematische Darstellung der Steuer- und Schaltvorrichtung und

Fig. 12 & 13

Z-Kran in Parkierstellung (zusammengeklappt).

Specifically, such a crane can be used on a vehicle. Further details and advantages of the present invention will be explained in more detail below with reference to the description of the figures with reference to the exemplary embodiments illustrated in the drawing. Show:

Fig. 1 to 8

Embodiments of an inventive arrangement in 8 schematic views,

Fig. 9 to 11

schematic representation of the control and switching device and

FIGS. 12 & 13

Z crane in parking position (folded).

In Fig. 1 a first crane arm 11 is shown, which is articulated via the hinge 14 with a second crane arm 12. At the bottom of the first crane arm 11, the further drive is mounted, which has a piston-cylinder unit 3. The piston-cylinder unit 3 is connected via a chain 5 with the second crane arm 12. The pivoting proceeds as before - without the intervention of the further drive - the piston-cylinder unit 13 extends the second crane arm 12 until the piston-cylinder unit 13 reaches the area of the dead center (if the longitudinal axis of the piston-cylinder). Unit 13 and the hinge 14 are in line). Due to the gravitational force, the dead center position is overcome and the piston-cylinder unit 13 can retract and move the second crane arm 12. For pivoting the second crane arm 12, the piston-cylinder unit 13 extends until it reaches the area of its dead center. Now the piston-cylinder unit 3 of the further drive enters, the chain 5 moves the second crane arm 12 and the piston-cylinder unit 13 overcomes its dead center position. Subsequently, the piston-cylinder unit 13 continues until the two crane arms reach their end position, the parking position.

In Fig. 2 is a variant too Fig. 1 can be seen, in which the piston-cylinder unit 3 of the further drive is attached to the upper side of the second crane arm 12. The course of the chain 5 of the further drive is also from the bottom of the first crane arm 11 to the top of the second crane arm 12. The operation of the Einschwenkvorganges is mutatis mutandis to the description of Fig. 1 ,

In Fig. 3 a releasable coupling device 6 is shown, in which a first coupling part 7, which is designed as a catching device, is attached to the first crane arm 11 and the second coupling part 8 on the piston-cylinder unit 3 of further drive is attached. In the area of the dead center position of the piston-cylinder unit 13, the piston-cylinder unit 3 of the further drive enters and the second coupling part 8 engages in the first coupling part 7 and thus causes the second crane arm 12 is folded up and the Piston-cylinder unit 13 is released from its dead center. Subsequently, the piston-cylinder unit 13 continues until the two crane arms reach their end position, the parking position, while the two coupling parts 7 and 8 have separated again during retraction.

In Fig. 4 is a variant of Fig. 3 to see, in which the piston-cylinder unit 3 of the further drive on the first crane arm 11 and the first coupling part 7, also designed as a catching device, on the second crane arm 12. The operation of the Einschwenkvorganges is identical to the description of the identical Fig. 3 ,

In Fig. 5 is shown how the piston-cylinder unit 3 of the further drive, which is located on the first crane arm 11, presses on a lever 9, which is located on the second crane arm 12, and thus the dead center of the piston-cylinder unit 13 to the joint 14th can overcome. The course of the Einschwenkvorganges is mutatis mutandis identical to the examples shown above.

In Fig. 6 is a variant of Fig. 5 shown, in which the piston-cylinder unit 3 of the further drive on the second crane arm 12 and the lever 9 on the first crane arm 11 is located. The course of the Einschwenkvorganges is mutatis mutandis identical to the examples shown above.

In Fig. 7 is a variant too Fig. 1 shown, in which the further drive is carried out in the interior of the first crane arm 11 and is not located on the outside of one of the two crane arms. This results in a maximum space savings. The operation of the Einschwenkvorganges is identical to the description of Fig. 1 ,

In Fig. 8 an asymmetrical arrangement of the piston-cylinder unit 13 to the piston-cylinder unit 3 of the further drive from the first crane arm 11 to the second crane arm 12 is shown, wherein the piston-cylinder unit 13 is mounted on the left side of the crane arms and the Piston-cylinder unit 3 of the further drive the right side of the crane arms is attached. For the sake of clarity are in the Fig. 8 both piston-cylinder units visible, so that the differences are more visible. In this case, the piston-cylinder unit 3 of the further drive is articulated at a different, lower position on the crane arm 12 than the piston-cylinder unit 13, which shows that the dead center of the respective piston-cylinder unit at a different position of the Joint 14 enters. For pivoting the second crane arm 12, both the piston-cylinder unit 13 and the piston-cylinder unit 3 of the further drive extends until the piston-cylinder unit 13 reaches the area of its dead center. The piston-cylinder unit 3 of the further drive has not yet reached its dead center and continues to drive, causing the piston-cylinder unit 13 to overcome its dead center. Then the two piston-cylinder units drive in until the two crane arms reach their end position, the parking position.

In Fig. 9 a control device 20 is shown, which causes via the switching device 21, the piston-cylinder unit 13 to perform a reversal of direction of their effective direction. This direction reversal is triggered by the switching valve 22, which acts as a limit switch.

In Fig. 10 are the two unfolded crane arms of a crane and a switching valve 22 is shown, which causes the control device 20 in the dead center of the piston-cylinder unit 13 to the joint 14 to perform a direction reversal of the effective direction of the piston-cylinder unit 13. Thus, no manual countermeasure or switching by the operator is required and the two crane arms drive to their final position, the parking position.

In Fig. 11 a control device 20 is shown, which causes via the switching device 21, the piston-cylinder unit 13 to perform a reversal of direction of their effective direction. This direction reversal is triggered by the switching valve 22 (see also Fig. 8 ). Furthermore, the piston-cylinder unit 3 is caused via the switching device 24 to perform a reversal of direction of their effective direction. This direction reversal is triggered by the switching valve 23 (see also Fig. 8 ).

In Fig. 12 a folded Z-crane 1 is shown, consisting of a crane column 2 and two crane arms. The piston-cylinder unit 3 of the further drive is executed in the interior of the first crane arm 11.

Fig. 13 also shows a collapsed Z-crane 1 (parking position) in which the piston-cylinder unit 3 of the further drive on the first crane arm 11 is executed on the outside.

Although the invention has been described concretely with reference to the embodiment shown, it goes without saying that the subject of the invention is not limited to this embodiment. Rather, it goes without saying that measures and modifications that serve to implement the idea of the invention, quite conceivable and desirable.

LIST OF REFERENCE NUMBERS

1

Z-Crane

2

Kransäule

3

Piston-cylinder unit of the further drive

4

Draw point of the chain 5

5

Chain

6

coupling device

7

First coupling part

8th

Second coupling part

9

lever

11

First crane arm

12

Second crane arm

13

Piston-cylinder unit

14

joint

20

control device

21

Switching device of the piston-cylinder unit 13th

22

Switching valve of the switching device 21

23

Switching valve of the switching device 24

24

Switching device of the piston-cylinder unit 3rd

Claims (17)

Crane, in particular vehicle crane, with a first crane arm and at least one second crane arm, - Which are connected by a joint and - Above a piston-cylinder unit having a drive relative to each other are pivotable, each starting from one of the two end positions in softer crane arms are substantially parallel to each other until reaching a dead center when the longitudinal axis of the piston-cylinder unit in Essentially located on a line with the joint,
characterized in that at least one further drive is provided, through which the dead center of the piston-cylinder unit (13) to the joint (14) can be overcome. Crane according to claim 1, characterized in that the further drive comprises a linear drive. Crane according to claim 2, characterized in that the linear drive has at least one Koiben-cylinder unit (3). Crane according to one of claims 1 to 3, characterized in that the further drive comprises a traction means, which extends in substantially elongated crane arms from the bottom of the first crane arm (11) to the top of the second crane arm (12). Crane according to claim 4, characterized in that the traction means is a chain (5). Crane according to one of claims 1 to 3, characterized in that the further drive via a releasable coupling device (6) with the first crane arm (11) or the second crane arm (12) is in operative connection at least in the region of the dead center. Crane according to Claim 6, characterized in that the coupling device (6) has a first coupling part (7) mounted on the first crane arm (11) and having a corresponding second coupling part (8) mounted on the second crane arm (12), at least in the region the dead center - is coupled and outside the range of the dead center of this second coupling part (8) is dissolved. Crane according to claim 7, characterized in that the coupling device (6) has at least one lever (9). Crane according to one of claims 1 to 8, characterized in that the further drive at least partially, preferably substantially completely, in the interior of the first crane arm (11) or the second crane arm (12) is arranged. Crane according to one of claims 1 to 9, characterized in that at least one of the crane arms (11, 12) is designed to be telescopic. Crane according to one of claims 1 to 10, characterized in that a control device (20) is provided, through which the piston-cylinder unit (13) at a certain angle of the first crane arm (11) to the second crane arm (12) a switching the effective direction of the piston-cylinder unit (13) experiences. Crane according to claim 11, characterized in that at least one switching device (21) is provided, the signals of the control device (20) can be fed. Crane according to claim 12, characterized in that the switching device (21) has a switching valve (22) through which the direction of action of the piston-cylitizer unit (13) is reversible when the switching point is reached. Crane according to one of claims 1 to 13, characterized in that the joint position of the two crane arms, at which the dead center of the piston-cylinder unit (13) to the joint (14) occurs, deviates from the joint position, to the dead center position of the piston-cylinder unit (3) of the further drive to the joint (14) occurs. Crane according to one of claims 1 to 14, characterized in that the piston-cylinder unit (13) and the piston-cylinder restraint (3) of the further drive are articulated asymmetrically on at least one of the two crane arms. Crane according to one of claims 1 to 15, characterized in that the crane is designed as a Z-crane (1). Vehicle with a crane according to one of claims 1 to 16.

Images