locking head

Abstract

The invention relates to a locking head for a telescopic cylinder of a telescopic boom with several telescopic boom sections, comprising a housing, two translationally displaceable cylinder bolts for locking the locking head in a telescopic boom section, and a telescopic bolt body displaceable transversely to the direction of action of the cylinder bolts, which serves to actuate the unlocking of successive telescopic boom sections, wherein two diametrically opposed guide housings are arranged in the telescopic bolt body, wherein the telescopic bolt body is guided in the guide housing by several guide elements arranged circumferentially on the side of the telescopic bolt body, and wherein the cylinder bolts can only be retracted if their stroke is free, and wherein the respective stroke can be blocked by means of a locking bolt.According to the invention, the locking bolt has a shaft, the end of which forms an end section that is smaller in cross-section than the shaft and has an I-shaped cross-section.

Description

[0001] The invention relates to a locking head for telescoping cylinders of a crane boom comprising several telescoping boom sections, preferably of a mobile crane.

[0002] Telescoping cylinders are used to extend the individual telescopic boom sections of the crane boom. In the extended position, the telescopic boom sections are locked together via a locking head.

[0003] Before a telescopic boom section can be extended, it must be coupled to the locking head. This is achieved by extending two cylinder bolts, which engage with the telescopic boom section. The telescopic boom section, still coupled to the adjacent section, is then unlocked using a corresponding release mechanism. For example, a spring-loaded bolt can be pulled by means of a claw-shaped release mechanism. The locking head is then moved by the telescoping cylinder, extending the inner telescopic boom section. In the extended position, the telescopic boom section must first be locked again to the adjacent section. This requires returning the claw-shaped release mechanism to its initial position.Only when the two adjacent telescopic boom sections are locked together may the cylinder locks between the locking head and the telescopic boom section be released. The telescoping cylinder then retracts to extend another telescopic boom section, if necessary, as described above.

[0004] From DE 50 2011 004 730 C5, a locking head for telescopic cylinders of a crane boom comprising several telescopic boom sections is known, which has a housing and cylinder bolts that are translationally displaceable within the housing for locking the locking head to a telescopic boom section. Furthermore, a telescopic bolt body is provided, which is translationally displaceable transversely to the direction of travel of the cylinder bolts and serves to actuate the unlocking of successive telescopic sections. A guide housing is arranged circumferentially on the side of the telescopic bolt body.

[0005] The telescopic bolt body features locking bolts that can be moved into the stroke of a locking bolt operatively linked to the movement of a cylinder bolt, or directly into the stroke of a cylinder bolt. According to the known solution, the locking bolts have an end section with an enlarged cross-section. This enlarged end section ensures that, if it engages directly within the stroke of a cylinder bolt, it can completely block the stroke. The diameter of the end section is precisely matched to the stroke of the locking bolt. This matching is further achieved by the diametrically opposed flattened sections on the end sections. The respective end sections have a U-shaped cross-section, providing sufficient space for a spring receptacle that passes transversely through the end section.In this configuration, the respective cylinder bolt is pushed outwards by a spring, which acts centrally on the rear of the cylinder bolt. To allow the locking bolt to penetrate far enough into the cylinder bolt's stroke, a corresponding U-shaped recess for the spring is provided. This means that the end section is open downwards, i.e., in its displacement direction, so that the spring receptacle can be slipped over the cylinder bolt's return spring without colliding with it.

[0006] In this known solution, each cylinder bolt has its own individual return spring. Such an arrangement can be prone to failure. For example, during fatigue tests at low temperatures, damage due to spring breakage has occurred.

[0007] A locking head of this type for telescopic cylinders, comprising the features of the preamble of claim 1, is known from DE 10 2023 108 833 A1. DE 10 2021 119 612 A1 also describes a locking head for telescopic cylinders of a telescopic boom.

[0008] The object of the invention is to improve the functional reliability of a locking head of the generic type.

[0009] The solution to this problem according to the invention results from the combination of the features of claim 1.

[0010] Accordingly, a locking head for a telescoping cylinder of a telescopic boom with several telescopic boom sections is proposed, comprising a housing, two translationally displaceable cylinder bolts for locking the locking head in a telescopic boom section, and a telescopic bolt body displaceable transversely to the direction of action of the cylinder bolts, wherein the telescopic bolt body serves to actuate the unlocking of successive telescopic boom sections, wherein two diametrically opposed guide housings are arranged in the telescopic bolt body, wherein the telescopic bolt body is guided in the guide housing by several guide elements arranged circumferentially on the telescopic bolt body, and wherein the cylinder bolts can only be retracted if their stroke is free, and wherein the respective stroke can be blocked by means of a locking bolt.The locking bolt according to the inventive solution now has a shaft, the end of which forms an end section that is smaller in cross-section than the shaft and has an I-shaped cross-section.

[0011] According to this solution, instead of a single return spring for the respective cylinder bolts, which is encompassed by a U-shaped end section of the locking bolt, an end section with a smaller cross-section than the shaft and an I-shaped cross-section is formed. In the locked state, this end section is framed laterally by two return springs arranged parallel to each other. Thus, according to this solution, the single spring is replaced by two parallel springs. This significantly increases the safety against a complete failure of the return force. Should one of the two springs break, the force of the other spring is still sufficient to move the cylinder bolt into its extended position. While a comparatively slower extension of the cylinder bolt due to the reduced spring force may be acceptable, this is a significant advantage.However, the solution ensures that the respective cylinder bolt is reliably positioned.

[0012] Advantageous embodiments of the invention are set out in the dependent claims following the main claim.

[0013] The spring mounts are advantageously spaced so far apart that the I-shaped end section of the locking bolt can plunge its narrow side between them.

[0014] Preferably, the telescopic bolt body is guided in the housing in various ways via guide elements, wherein the guide elements merge integrally into the locking bolts, which can be moved directly into the stroke of the cylinder bolts.

[0015] According to a further embodiment of the invention, at least two unlocking pistons are provided for moving each of the guide elements of the telescopic bolt body.

[0016] Finally, a telescoping cylinder for a telescoping boom, in particular of a mobile crane, is claimed, having a locking head which has the features described above.

[0017] Further features, details and advantages of the invention will become apparent from the exemplary embodiment shown in the following drawing.

[0018] They show: Fig. 1: a cross-section through a locking head according to the invention along line AA of the Fig. 2, Fig. 2: a locking head according to the Fig. 1 in top view and Fig. 3: a partial section along line FF according to Fig. 1.

[0019] In Fig. Figure 1 shows a locking head 1 in cross-section. The attachment of the locking head 1 to a telescoping cylinder of a crane boom comprising several telescopic boom sections is not shown in detail. The locking head 1 includes a housing 2 in which slidably arranged cylinder bolts 3 and 4 are arranged. The cylinder bolts 3 and 4 extend from the housing 2 in opposite directions and serve to lock the locking head 1 to a telescopic boom section, thus allowing it to move along with the telescoping cylinder. The cylinder bolts 3 and 4 lock the locking head 1, and consequently the telescoping cylinder, to the telescopic boom sections. This unit can be referred to as a cylinder lock (ZV).

[0020] In the Fig. Figure 1 shows the two cylinder bolts 3 and 4 in the extended position. This locks the locking head 1 and, consequently, the telescoping cylinder with a telescoping boom extension.

[0021] A telescopic bolt body 5 is slidably mounted transversely to the cylinder bolts 3, 4 within the housing 2. The telescopic bolt body 5 serves to engage a release bolt (not shown in detail here) and pull it towards the housing 2. This allows the locking of two adjacent telescopic boom sections to be released, whereby the inner telescopic section, which is locked to the locking head via the cylinder bolts 3, 4 for this purpose, can be moved along with it.

[0022] In the execution according to the Fig. In section 1, the telescopic bolt body 5 is configured as a claw that can engage behind an undercutting head of a release bolt. The telescopic bolt body 5 is a component of the so-called telescopic locking device TV. In the Fig. In the position shown in Figure 1, the telescopic bolt body 5 is at its upper dead center. Here, the telescopic bolt body 5, with the release bolts (not shown), could be moved downwards due to the installed cylinder bolts 3, 4.

[0023] The cylinder bolts 3, 4 are actuated hydraulically via plungers 6, which act on a collar 7 of the cylinder bolts 3, 4. Several plungers 6 are provided for each cylinder bolt 3, 4. The individual plungers 6 of each cylinder bolt 3, 4 are connected to each other via a circulation channel, ensuring uniform pressure application. The cylinder bolts 3, 4 are returned by spring force. For this purpose, two return springs 8 are provided for each cylinder bolt 3, 4, which are arranged in corresponding spring receptacles 9 within the cylinder bolts 3, 4 and are each supported against the housing 2. The respective position of the cylinder bolts 3, 4 can be monitored by means of position detection 10, 11.

[0024] The cylinder bolts 3 and 4 can only be retracted if the stroke is clear. The stroke of the cylinder bolts 3 and 4 can be selectively blocked by means of locking bolts 12. Each locking bolt 12 has a shaft, and at the end of this shaft, the cross-section of the locking bolt is reduced compared to the shaft by forming an I-shaped end section. The width of the end section 13 (see figure) Fig. 3) is precisely matched to the stroke of the associated cylinder bolt 3, 4. For this purpose, it has diametrically opposed flattened sections 14, 15. In addition, the end section 13, as previously described, has an I-shaped cross-section. From the sectional view in Fig. Figure 3 shows that the lower part of the end section 13 has laterally open areas in the plane of the image, i.e., in the direction of the two parallel return springs 8, so that the end section 13 can move downwards between the two return springs 8 when the locking bolt 12 is moved downwards. The end section 13 thus has lateral spring receptacles 16 on each side (see Figure 3). Fig. 3) in the form of laterally designed recesses.

[0025] The telescopic bolt body 5 is guided by means of guide elements 17, which are connected to it via a collar formed on the telescopic bolt body. The guide elements 17 extend as shown in Fig. As shown in Figure 1, each locking bolt 12 with its end section 13 is engaged. During the movement of the telescopic bolt body 5, the guide elements 17 take over the task of guiding the telescopic bolt body. The telescopic bolt body 5 is actuated by release pistons 20. These are arranged symmetrically around the guide elements 17, as shown in the top view of Figure 1. Fig. 2 can be seen. The telescopic bolt body 5 is held in the extended end position by springs 18. Fig. 1 held and, for example, pulled by hydraulic pressure on the release pistons 20. As in Fig. As indicated in Figure 1, the springs 18, the release piston 20, and the associated guide element 17 are arranged side by side. These components can be arranged essentially planarly to one another and / or be mounted so as to be slidably parallel to each other.

Claims

[1] Locking head (1) for a telescoping cylinder of a telescopic boom with several telescopic boom sections, comprising a housing (2), two translationally displaceable cylinder bolts (3, 4) for locking the locking head (1) in a telescopic boom section, and a telescopic bolt body (5) displaceable transversely to the direction of action of the cylinder bolts (3, 4), which serves to actuate the unlocking of successive telescopic boom sections, wherein two diametrically opposed guide housings (22) are arranged in the telescopic bolt body (5), wherein the telescopic bolt body (5) is guided in the guide housing (22) by several guide elements (17) arranged circumferentially on the telescopic bolt body (5), and wherein the cylinder bolts (3, 4) can only be retracted if their stroke is free, wherein the respective stroke can be blocked by means of a locking bolt (12), and wherein each cylinder bolt (3,4) each has two spring receptacles (9) for receiving return springs (8), , characterized by , that the locking bolt (12) has a shaft, the end of which forms an end section that is smaller in cross-section than the shaft and has an I-shaped cross-section. [2] Locking head (1) according to claim 1, characterized by that the spring receptacles (9) are spaced apart so that the I-shaped end section of the locking bolt (12) can dip its narrow side between them. [3] Locking head (1) according to any one of the preceding claims, characterized by , that the telescopic bolt body (5) is slidably guided in the housing (2) via guide elements (17), the guide elements being integrally integrated into the locking bolts (12), which can be directly displaced into the stroke of the cylinder bolts (3, 4). [4] Locking head (1) according to claim 3, characterized by, that at least two unlocking pistons (20) are provided for moving each of the guide elements (17) of the telescopic bolt body (5). [5] Telescoping cylinder for a telescoping boom, in particular of a mobile crane, with a locking head (1) according to one of claims 1 to 4.

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