EP0460476B1 - Telescopic jib with extension mechanism - Google Patents

Description

The invention relates to a telescopic boom of the type specified in the preamble of the claim. Such a telescopic boom is already known from DE 35 10 710 C2.

This publication shows a three-part telescopic boom with two telescopic boom parts and a hydraulic piston-cylinder unit, the individual boom parts being lockable against one another and in which by coupling the head of the piston rod at two different locations within the inner telescopic part (the head part) two different boom lengths , namely 2/3 of the maximum length or the entire maximum boom length, can be realized. If instead of a simple hydraulic cylinder a hydraulic cylinder with telescopic piston rod with n steps is used, then (n + 1) telescopic boom parts or a boom with a total of (n + 2) boom parts can be handled.

From US-A-4,514,939 a telescopic boom is known, which consists of a base body and several telescopic boom parts and a hydraulic piston-cylinder unit. In this known telescopic boom, the free end of the piston rod of this piston-cylinder unit can only be connected to the base body at a single point. Otherwise, the free end of this piston rod can only be connected to the next smaller boom part.

In its second position, the piston-cylinder unit is only indirectly coupled to the base part, specifically via its coupling to the first telescopic boom part.

With increasing number of stages of the extension arrangement, the weights of the Telescopic boom and the technical effort required for this. As the weight of the boom increases, the permissible load decreases under otherwise the same conditions, especially with a given axle load of a crane vehicle.

The invention has for its object to design a telescopic crane boom of the type specified in the preamble of the claim so that in comparison with known crane booms with a given extension arrangement, a further telescopic boom part can be handled or that the allowable for a crane boom with a predetermined number of boom parts Load can be increased at least for partial lengths of the boom.

This object is achieved by the subject matter of the patent claim.

If the push-out arrangement consists of several push-out devices, for example hydraulic cylinders, the measure according to the invention relates analogously to that push-out device, which is located inside the body.

Based on the fact that the push-out arrangement is initially coupled to the base body in the end facing away from the head part or the cable pulley arrangement, it is possible with the measure according to the invention to push out all telescopic boom parts together, these being locked together in a known manner. In the first extension stage, it is therefore not the weakest cross section of the head part that is used, but rather the relatively load-bearing cross section of the telescopic boom part immediately following the base body. As a result, a larger load can be attached to this partial length.

To extend the boom further, the coupling between the push-out arrangement and the base body can be released and the push-out arrangement can be moved back to its original length. Since the push-out arrangement is articulated in the head part of the boom, this means that the articulation or coupling point of the push-out arrangement is pulled within the base body by a stroke length in the direction of the cable pulley arrangement or the head part. In this second position, the push-out arrangement is newly coupled to the base body, and with each stroke of the push-out arrangement, the boom can be extended or extended by a partial length in a known manner. Overall, with the measure according to the invention, in the case of a push-out arrangement with n strokes or steps (n + 1), jib parts with at least partially larger permissible load values can be handled. If the extension arrangement can also be coupled in the head part of the boom at two axially different locations, even (n + 2) telescopic boom parts or a boom with a total of (n + 3) boom parts (including base body) can be handled.

In any case, with a predetermined number of telescopic parts, the push-out arrangement can be made simpler by one stroke or one step than known telescopic booms and can thus be produced with less effort. This also saves material and weight, which can be used to reinforce the load-bearing parts of the boom.

Since the push-out arrangement can be coupled at axially different locations both in the base body and in the head part of the boom, identical coupling devices are provided for coupling the parts mentioned, but differ only in the width caused by the different cross-section of the boom parts. The identical construction has a cost-effective effect both in procurement and in the provision of spare parts.

Fig. 1

einen erfindungsgemäßen Teleskopausleger in der zusammengeschobenen Transportstellung in einem schematisierten Längsschnitt,

Fig. 2

den Ausleger im ausgefahrenen Zustand im Längsschnitt,

Fig. 3

einen teilweisen Querschnitt durch den Ausleger längs der Linie III-III in Fig. 1 und

Fig. 4

den Ausleger mit einer Verriegelungsanordnung in einer auszugsweisen Seitenansicht

An embodiment of the invention is shown in the drawings and is explained in more detail below. Show it

Fig. 1

a telescopic boom according to the invention in the compressed transport position in a schematic longitudinal section,

Fig. 2

the boom in the extended state in longitudinal section,

Fig. 3

a partial cross section through the boom along the line III-III in Fig. 1 and

Fig. 4

the boom with a locking arrangement in a partial side view

The boom 1 shown is part of a (not shown) mobile crane. It can be raised and lowered about a horizontal axis 2 and can be rotated or pivoted about a vertical axis, as disclosed, for example, in DE-OS 30 28 241 (FIG. 1).

The jib 1 has five box-shaped jib parts: the base body 3 which is articulated directly on the mobile crane in the horizontal axis 2, three further telescopic intermediate parts 4, 5, 6 and the telescopic head part 7 with the head 8, in which one or more rollers 9 for guidance of the rope 10 are arranged. Each boom part 3 ... 7 can be locked to the boom part adjacent to it by a locking arrangement with two lateral locking devices 11.3 (on the base body 3), 11.4 (on the intermediate part 4), etc., as described, for example, in DE-PS 35 10 710 are disclosed.

On the inside of the webs 12 of the boom parts 3, 7, an upper and a lower guide rail 15, 16 are arranged parallel to the main axis 13 of the boom 1. Between the guide rails 15, 16, recesses 17 are provided in the webs 12 of the cantilever parts 3, 7 on both sides in the middle between the guide rails 15, 16, specifically in the base body 3 the recesses 17.3.1 in the region of the horizontal axis 2 and 17.3.2 in the area pointing away from the horizontal axis 2 and in the head part 7 the recesses 17.7.1 (in the area facing the base body 3) and (in the vicinity of the head 9) 17.7.2 (unless a specific recess is meant in the following) generally used the reference number 17).

A hydraulic cylinder 20 with a two-stage piston rod 21, 21a is located within the boom parts 3 ... 7. A coupling device 22.3 or 22.7 is attached to both the base of the actual hydraulic cylinder 20 and the free end of the piston rod 21a. These coupling devices (also referred to in the following only briefly as 22) have outward-pointing securing or coupling bolts 27 which engage in the coupling position in the recesses 17 in the webs 12 of the boom part 3 or 7. For the uncoupling, a gaseous or liquid pressure medium can be used, which reaches the coupling device through a connection 34. In the event of pressurization by the medium, the coupling bolts 27 are moved in the direction of the vertical longitudinal center plane 35 of the boom parts 3, 7 or the entire boom 1 and withdrawn from the recesses 17 of the webs 12: the hydraulic cylinder 20 or the piston rod 21a are from decoupled the boom part 3 or 7. The coupling devices 22.3 and 22.7 are slidably guided between the guide rails 15, 16.

The coupling devices 22.3 and 22.7 have the same structure with one another. They differ, due to the size of the assigned boom parts 3 and 7, only in their width or their axial extent.

The hydraulic cylinder 20 and the coupling devices 22.3 or 22.7 can be supplied with pressure medium via flexible lines (not shown) from a hose or cable drum or via an energy chain 37 known per se.

To monitor the position of the coupling pin 27 are such. B. disclosed in DE-PS 35 10 710, mechanical limit switches or inductive proximity switches are provided. Both the actuation and the monitoring of the coupling devices 22.3 and 22.7 can thus be carried out centrally from the control station of the mobile crane.

In the pushed-together transport position of the boom 1, the coupling bolts 27 of the coupling devices 22.3 or 22.7 engage in the recesses 17.3.1 at the beginning of the base body 3 or 17.7.2 at the end of the head part 7.

By extending the piston rod 21, the boom or telescopic parts 4 to 7 are pushed out together on the base body 3 when the locking arrangement 11.3 is unlocked and the locking arrangement 11.3 is then locked again. In a further step, the locking arrangement 11.4 is unlocked and the telescopic parts 5 to 7 are extended together in a second stage by further extending the piston rod 21a.

After locking the locking arrangement 11.4, the coupling bolts 27 of the coupling device 22.3 are withdrawn from the recesses 17.3.1 of the basic boom 3, so that the hydraulic cylinder 20 is uncoupled from the basic body 3. In the following, the piston rod 21a is retracted. Since the piston rod 21a is coupled to the head part 7, this means that the cylinder 20 - with the uncoupled coupling device 22.3 - is pulled towards the head part 7 with a given relative movement to the piston rods 21, 21a. The coupling device 22.3 slides at the foot of the Cylinder 20 in the guide rails 15, 16 of the base body 3 in the direction of the head part in the position shown in Fig. 2. By blocking or releasing the pressurization of the coupling device 22.3 through the connection 34, the coupling bolts 27 are pressed into the recesses 17.3.2 in the new position in the area of the base body 3 facing away from the axis 2 by the springs 30.

When the piston rod 21a is extended again, the two outer telescopic parts 6, 7 are extended together from the new position of the hydraulic cylinder 20 given by the recesses 17.3.2. By uncoupling the coupling device 22.7 from the recesses 17.7.2 and pulling back the piston rod 21a, the piston rod 21a can be coupled to the head part 7 in the position shown in FIG. 2 by the recesses 17.7.1. By extending the piston rod 21a again, the boom is brought into its largest extent, shown in FIG. 2.

To achieve a better subdivision of the extension length, the base body 3 and the head part 7 can of course have further recesses at predetermined intervals between the recesses 17.3.1 and 17.3.2 or 17.7.1 and 17.7.2.

Claims (1)

1. A telescopic jib, consisting of a base element and a number of telescopically movable jib parts and an extension system, each pair of adjacent jib parts being lockable together and the extension system (20, 21, 21a) being adapted to be coupled, for axial loading, to the telescopically movable head part by means of a coupling device (22, 7) at two axially different locations (17.7.1; 17.7.2), the distance between which corresponds substantially to the length of travel of a telescopically movable jib part (4, 5, 6, 7), characterised in that the extension system (20, 21, 21a) is adapted to be coupled by another coupling device (22.3) to the base element (3) for axial loading at two axially different locations (17.3.1; 17.3.2), the distance between which again corresponds substantially to the length of travel of a telescopically movable jib part (4, 5, 6, 7), the two coupling devices (22.3; 22.7) being of identical construction, except for their width.

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