locking head

Abstract

Locking head for telescopic cylinders of a crane boom comprising several telescopic sections, comprising a housing (2) and cylinder bolts (3a, 3b) that are translationally displaceable in the housing (2) for locking the locking head (1) with a telescopic section and with a telescopic bolt body (4) that is displaceable relative to the housing (2) for actuating the unlocking of two successive telescopic sections, wherein the telescopic bolt body (4) is displaceable transversely to the cylinder bolts (3a, 3b) and wherein a locking element (8a, 8b) blocks the stroke of the cylinder bolt (3a, 3b) when the telescopic bolt body (4) is retracted and releases the stroke when the telescopic bolt body (4) is extended, wherein the telescopic bolt body (4) is connected by a piston rod (11a, 11b) to a piston (10a, 10b) guided in a cylinder chamber (9a, 9b), wherein on the piston rod (11a, 11b) opposite side of the piston (10a, 10b) the locking element (8a,8b) is arranged, which, when the telescopic bolt body (4) is extended, is located at least partially in the cylinder chamber (9a, 9b) of the piston (10a, 10b), wherein the telescopic bolt body (4) is retractable against a spring force, characterized in that the locking element (8a, 8b) is located predominantly within the cylinder chamber (9a, 9b) when the telescopic bolt body (4) is extended.

Description

[0001] The invention relates to a locking head for telescopic cylinders of a crane boom comprising several telescopic sections, with the features in the preamble of claim 1.

[0002] The individual telescopic sections of a mobile crane's boom are extended one after the other using a telescoping cylinder and locked together in the extended position. This requires a locking mechanism that can be locked and unlocked in different positions.

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

[0004] Crucial for operational reliability is the reliable control of the locking mechanism. In this context, for example, EP 0 754 646 B1 proposes a system in which the mechanisms are combined in such a way that a locking bolt encompassing two adjacent telescopic sections can only be released once the cylinder bolts are engaged, and the cylinder bolts can only be disengaged once the released locking bolt has been re-engaged after the stroke has been completed.

[0005] For the prior art, reference is also made to DE 10 2010 022 865 A1, which discloses a locking head for telescopic cylinders with a housing and with cylinder bolts that are translationally displaceable within the housing for locking the locking head with a telescopic section, and with a telescopic bolt body that is displaceable transversely to the direction of action of the cylinder bolts and serves to actuate the unlocking of successive telescopic sections. A guide housing is arranged circumferentially around the telescopic bolt body. The telescopic locking body has a collar against which hydraulically actuated unlocking pistons arranged in the guide housing press to unlock the cylinder. The pistons on the side of the collar facing away from the cylinder bolts thus project relatively far beyond the housing.

[0006] Based on this, the invention aims to demonstrate a locking head whose construction volume and thus weight are further reduced.

[0007] This problem is solved by a locking head with the features of claim 1.

[0008] Advantageous further developments of the inventive concept are the subject of the dependent claims.

[0009] For the prior art, reference is made to DE 10 2009 009 944 A1, which discloses a further embodiment of a locking head. This embodiment aims to reduce the number of parts and the weight and cost of the components. Unnecessary components, such as racks, sliding cams, spring elements, etc., are to be avoided in order to reduce costs and weight and to provide a means of directly monitoring the bolt positions. By omitting these parts, the sensors should still be able to indicate a secure bolt position even if a rack or sliding cam breaks. Therefore, the cylinder bolts are not supported by springs, but rather engage directly with each other via a piston rod 3a acting between the cylinder bolts.For this purpose, the cylinder bolts are moved out of the plane of the telescoping cylinder and placed above the telescoping cylinder, which results in an increased overall height, but makes it possible to do without return springs.

[0010] From DE 10 2009 008 557 B4, a locking head for telescopic cylinders is known in which the locking claw is guided in the housing by a guide arranged circumferentially around the locking claw. The laterally extending cylinder bolts are coupled to each other via racks. The position is sensed in the area of ​​the rack.

[0011] The locking head according to the invention for telescopic cylinders of a crane boom comprising several telescopic sections has a housing and cylinder bolts that are translationally displaceable within the housing for locking the locking head to a telescopic section. Furthermore, the locking head has a telescopic bolt body that is displaceable relative to the housing for actuating the unlocking of two successive telescopic sections. The telescopic bolt body is displaceable transversely to the cylinder bolts. A locking element blocks the stroke of the cylinder bolt when the telescopic bolt body is retracted and releases the stroke of the cylinder bolt when the telescopic bolt body is extended. According to the invention, the telescopic bolt body is connected to a piston rod and to a piston guided in a cylinder chamber. The telescopic bolt body can be retracted against a spring force, i.e., displaced into an unlocking position.

[0012] The locking element is located on the side of the piston facing away from the piston rod. It is designed that, when the telescopic bolt body is extended, the locking element is at least partially located within the piston's cylinder chamber.

[0013] The essential difference compared to the locking head of DE 10 2010 022 865 A1 is that the hydraulic actuating means for the telescopic bolt body and the locking element are arranged on the same side, allowing the locking element to engage in the piston's cylinder chamber in a space-saving manner. Unlike a piston that extends to unlock, the piston in the locking head according to the invention is retracted by pressure on the piston's annular space. The piston and the locking element are located on a common side of the telescopic bolt body. The locking element is dimensioned to be long enough that it is located predominantly, and in particular completely, within the cylinder chamber when the telescopic bolt body is extended. Predominantly means more than 50% of its length, in particular more than 70%, and preferably more than 90% of its length.

[0014] From a design perspective, this means that the stroke of the telescopic locking bolt body still determines the stroke of the locking element, but without these two strokes being additive. This allows for a significantly more compact design, resulting in a substantial weight reduction of up to 50%. A shorter installation dimension for the locking head also enables the use of shorter telescopic cylinders, leading to further weight savings in these components as well. This, in turn, increases the lifting capacity of the crane boom.

[0015] Another advantage is that the more compact design results in more stable guidance of the telescopic bolt body in all directions. Furthermore, the components can be manufactured with significantly reduced production effort. In particular, the telescopic bolt body and the piston rod are formed from a single, uniform material. The locking element can also be described as an extension of the piston rod on the opposite side of the piston. This eliminates the need for separate locking elements that must be connected to or attached to the telescopic bolt body. Ultimately, this also simplifies assembly and reduces assembly effort, as fewer adjustments are required, such as the alignment of additional guide bodies and locking elements.

[0016] In a further development of the invention, the cylinder chamber is designed as a bore open at one end. There is no longer any radial offset between the bolt-like locking element and the piston rod. The longitudinal axes of the piston rod and the locking element are not only parallel but identical.

[0017] In this invention, the axial length of the locking head is minimized by the forked design of the locking element, which, when the telescopic bolt body is retracted, engages a return spring within the stroke of the cylinder bolt. This configuration is advantageous when the displacement axes of the telescopic bolt body intersect the axes of the cylinder bolts, and thus lie in a common plane. Internal return springs of the cylinder bolts are engaged by the forked locking element. This has the advantage that the stroke of the cylinder bolts can be completely blocked not only by engagement at the edges but also by engagement at the center. This prevents uneven loading of the cylinder bolts.A fork-shaped locking element therefore means that the locking element is open on one side in its displacement direction, so that the locking element can be slipped over the return spring of the cylinder bolt without colliding with it.

[0018] The telescopic bolt body can be guided internally, that is, inside, by the piston rod and piston. Alternatively, the telescopic bolt body can have guide surfaces via which it makes contact with the housing of the locking head on the outside (external guidance). In this case, the telescopic bolt body is guided externally, either alternatively or additionally.

[0019] The aforementioned guide surfaces can be formed on a guide housing connected to the housing. This guide housing can be manufactured separately as a pre-assembled unit and connected to the supporting housing of the locking head, in particular by screwing it in place. The piston's cylinder chamber can also be arranged in this guide housing. In other words, the complete actuating mechanism for the telescopic bolt body, including the telescopic bolt body itself, can be provided as a pre-assembled unit within the guide housing and connected to the supporting housing of the locking head. This allows for a modular system. Furthermore, the system according to the invention is preferably compatible with conventional cylinder locking drives already available on the market with regard to the telescopic bolt body.

[0020] An advantage of the invention is that, due to the arrangement of the axes of movement in a common plane, the locking head is subjected to less stress. Diametrically opposed piston rods or corresponding guide surfaces enable high force absorption with a small overall size and reduced weight. Furthermore, it is possible for all actuating elements for the telescopic bolt bodies and the cylinder bolts to be located in a single common plane. This allows the axial length, relative to the longitudinal axis of the telescopic cylinder, to be reduced to a minimum.

[0021] In summary, the locking head according to the invention can be described as follows: The telescopic bolt body is connected to several translationally displaceable piston rods. The piston rods are arranged outside the central axis of the opening for the telescoping cylinder. In particular, the piston rods have a clear distance between them that is greater than the opening for the telescoping cylinder within the housing of the locking head. The piston rods are connected to a piston that is tightly guided in a cylinder chamber. The piston can be retracted against a spring force. The piston rods are guided within the housing. For this purpose, the housing is designed as a guide housing in which both the piston rods and the piston are guided. On the side facing away from the piston rods, the guide housing has guide surfaces in the cylinder chamber for the piston. These guide surfaces on the side facing away from the piston rods can come into contact with locking elements that are connected to the piston.The locking elements are primarily cylindrical and essentially form part of the pistons. These sections of the pistons serve as locking elements. In the extended position, they can block the cylinder bolts from retracting. Their end-face recesses can engage the return springs of the cylinder bolts. For this purpose, the longitudinal axes of the cylinder bolts and the return springs are arranged so that they intersect the longitudinal axes of the pistons and piston rods. When the telescopic bolt body is extended, these same locking elements can be located predominantly, and in particular completely, within the cylinder chamber of the pistons. For this reason, the cylinder chamber is designed as an open cylinder bore, open across its entire cross-section towards the cylinder bolts. Guide surfaces are formed in the open cylinder bore, which contribute to the secondary guidance and support of the telescopic bolt body in all directions.

[0022] The telescopic bolt body, the cylinder bolts, the pistons with their piston rods, and the plungers for driving the cylinder bolts are all located in a common plane with respect to their respective central longitudinal axes. Therefore, no bending moments occur outside this plane. The design is exceptionally compact.

[0023] The invention is explained in more detail below with reference to an embodiment illustrated in the drawings. These show: Fig. 1 a cross-section through a locking head along line II-II of the Fig. 3 with the cylinder bolt retracted; Fig. 2 the locking head of the Fig. 1 with the cylinder bolt extended and the telescopic bolt body retracted and Fig. 3 the locking head of the Fig. 2 in the top view.

[0024] Fig. Figure 1 shows a locking head 1 in cross-section. The locking head 1 is attached, in a manner not shown in detail, to a telescoping cylinder of a crane boom comprising several telescopic sections. The locking head 1 includes a housing 2 in which translationally displaceable cylinder bolts 3a, 3b are arranged. The cylinder bolts 3a, 3b can be extended from the housing 2 in opposite directions and serve to lock the locking head 1 to a telescopic section, so that it moves along with the telescoping cylinder when it is extended or retracted. The cylinder bolts 3a, 3b lock the locking head 1 and thus the telescoping cylinder to the telescopic sections. This unit can be referred to as a cylinder lock ZV.

[0025] Fig. Figure 1 shows the two cylinder bolts 3a, 3b in the retracted state, that is, the locking head 1 and thus the telescopic cylinder is not locked with a telescopic shot (central locking unlocked).

[0026] A telescopic bolt body 4 is displaceable within the housing 2 transversely to the cylinder bolts 3a, 3b. The telescopic bolt body 4 serves to grasp and displace a release bolt (not shown) and pull it towards the housing 2. This releases the locking mechanism of two adjacent telescopic sections, allowing the inner telescopic section, which can be locked to the locking head 1 via the cylinder bolts 3a, 3b, to be moved. In this embodiment, the telescopic bolt body 4 is configured as a claw that can engage behind the undercut head of a release bolt. The telescopic bolt body 4 is part of the so-called telescopic locking mechanism TV. In the illustrated position, the telescopic bolt body 4 is at its top dead center. In this position, the release bolt (not shown) could be engaged.However, the telescopic bolt body 4 could not be moved downwards in the image plane, i.e., it could not be retracted, due to the retracted cylinder bolts 3a, 3b. For safety reasons, the cylinder bolts 3a, 3b would have to be extended, as shown in . Fig. 2 is shown.

[0027] The cylinder bolts 3a, 3b are actuated hydraulically by means of a so-called plunger locking mechanism. Plungers 5a, 5b, which act on collars 6a, 6b of the cylinder bolts 3a, 3b, move them in the direction of the Fig. 1. Arrows are shown. Each cylinder bolt 3a, 3b is fitted with a plunger 5a, 5b, both plungers 5a, 5b being located in the same plane of section. The cylinder bolts 3a, 3b are returned to their original position by a spring force. For this purpose, a return spring 7a, 7b is provided for each cylinder bolt 3a, 3b, which is arranged in a spring receptacle within the cylinder bolts 3a, 3b and is supported on the other side by the housing 2. The respective position of the cylinder bolts 3a, 3b can be detected by means of position detection (not shown in detail).

[0028] The cylinder bolts 3a, 3b can only be retracted if their stroke is unobstructed. It is intended that the stroke of the cylinder bolts 3a, 3b can be selectively blocked by means of locking elements 8a, 8b. As can be seen from the comparison of the Fig. 1 and Fig. As can be seen in Figure 2, the locking elements 8a, 8b are displaced so far into the stroke of the cylinder bolts 3a, 3b that the return spring 7a, 7b is engaged by the locking elements 8a, 8b. The locking elements 8a, 8b are therefore fork-shaped in a manner not shown in detail. The special feature is that the locking elements 8a, 8b have a length X ( Fig. 1) possess a diameter large enough that, when the telescopic bolt body 4 is extended, the locking elements 8a, 8b are completely enclosed within a cylinder chamber 9a, 9b, which is located directly adjacent to the stroke of the cylinder bolts 3a, 3b. The cylinder chamber 9a, 9b is designed as a bore open on one side towards the stroke of the cylinder bolts 3a, 3b and simultaneously serves to accommodate a piston 10a, 10b. A piston rod 11a, 11b is connected to each piston 10a, 10b and is linked to the telescopic bolt body 4. The piston rods 11a, 11b, the pistons 10a, 10b, and the locking elements 8a, 8b are each located on a common longitudinal axis. These two axes of the piston rods 11a, 11b define a plane in which the plungers 5a, 5b are also located. This means that all activatable propulsion devices are located in a common spatial plane.As a result, the overall length of the locking head 1 extending in the axial direction of the cylinder receptacle 12 for the telescopic cylinder (not shown in detail) is very small (. Fig. 3).

[0029] To actuate the telescopic bolt body 4, the pistons 10a, 10b must be retracted, which is only possible when the cylinder bolts 3a, 3b are extended ( Fig.2) For this purpose, the annular space surrounding the respective piston rod 11a, 11b within the cylinder chamber 9a, 9b is hydraulically pressurized. The pistons 10a, 10b thus have annular working surfaces 13a, 13b. The sealing of the pistons 10a, 10b against the cylinder chamber 9a, 9b is effected by sealing elements 14a, 14b, which are received in a groove of the respective piston 10a, 10b. The sealing elements 14a, 14b are supported on one side by the retaining elements 8a, 8b, which are dimensioned in diameter as large as the pistons 10a, 10b in the area of ​​their annular working surfaces 13a, 13b. This guides the telescopic bolt body 4 in the extended position by the two piston rods 11a, 11b and also by the pistons 10a, 10b with the locking elements 8a, 8b connected to them. The area provided for guidance, with which the piston rods 11a, 11b engage, is marked Z.It is located in the guide housings 15a, 15b, which are screwed onto the actual housing 2 with the cylinder receptacle 12. These are two separate guide housings 15a, 15b. Within these guide housings 15a, 15b are also the respective cylinder chambers 9a, 9b with the pistons 10a, 10b, the piston rods 11a, 11b, and the locking elements 8a, 8b. This assembly can be connected to the housing 2 as a prefabricated unit.

[0030] The telescopic bolt body 4 can also be guided externally, i.e., outside the guide housings 15a, 15b. For this purpose, guide surfaces Y can be formed on the telescopic bolt body 4, which can be brought into contact with internal guide surfaces 16 of the guide housings 15a, 15b.

[0031] The telescopic bolt body 4 is returned to its original position against the force of a return spring 17, which in this case is arranged centrally between the housing 2 and the telescopic bolt body 4. It is located in the same spatial plane as the cylinder bolts 3a, 3b and all the aforementioned actuating means for moving the telescopic bolt bodies 4 and cylinder bolts 3a, 3b, respectively. Reference symbol: 1 locking head 2 cases 3a Cylinder lock 3b Cylinder bolt 4 telescopic bolt bodies 5a Plunger 5b Plunger 6a Collar 6b collar 7a Return spring 7b Return spring 8a Safety element 8b Safety element 9a Cylinder space 9b Cylinder space 10a Piston 10b piston 11a Piston rod 11b Piston rod 12 cylinder mount 13a annular effective surface 13b annular effective surface 14a Sealing element 14b Sealing element 15a Guide housing 15b Guide housing 16 guide surface 17 Return spring TV telescopic lock X Length Y guide surface Z Guide section Central locking cylinder lock

Claims

[1] Locking head for telescoping cylinders of a crane boom comprising several telescoping sections, comprising a housing (2) and cylinder bolts (3a, 3b) that are translationally displaceable in the housing (2) for locking the locking head (1) with a telescoping section and with a telescoping bolt body (4) that is displaceable relative to the housing (2) for actuating the unlocking of two successive telescoping sections, wherein the telescoping bolt body (4) is displaceable transversely to the cylinder bolts (3a, 3b) and wherein a locking element (8a, 8b) blocks the stroke of the cylinder bolt (3a, 3b) when the telescoping bolt body (4) is retracted and releases the stroke when the telescoping bolt body (4) is extended, wherein the telescoping bolt body (4) is connected by a piston rod (11a, 11b) to a piston (10a, 10b) guided in a cylinder chamber (9a, 9b), wherein on the piston rod (11a, 11b) opposite side of the piston (10a,10b) the locking element (8a, 8b) is arranged which, when the telescopic bolt body (4) is extended, is at least partially located in the cylinder chamber (9a, 9b) of the piston (10a, 10b), wherein the telescopic bolt body (4) can be retracted against a spring force, , characterized by , that the locking element (8a, 8b) is located predominantly within the cylinder space (9a, 9b) when the telescopic bolt body (4) is extended. [2] Locking head according to claim 1, characterized by , that the locking element (8a, 8b) is completely inside the cylinder space (9a, 9b) when the telescopic bolt body (4) is extended. [3] Locking head according to claim 1 or 2, characterized by , that the telescopic bolt body (4) and the piston rod (11a, 11b) are formed in one piece from a single workpiece made of the same material. [4] Locking head according to any one of claims 1 to 3, characterized by , that the cylinder space (9a, 9b) is designed as a bore open on one side. [5] Locking head according to any one of claims 1 to 4, characterized by , that the locking element (8a, 8b) is fork-shaped and, when the telescopic bolt body (4) is retracted, a return spring (7a, 7b) overlaps in the stroke of the cylinder bolt (3a, 3b). [6] Locking head according to any one of claims 1 to 4, characterized by , that the telescopic bolt body (4) is guided by the piston rod (11a, 11b) and the piston (10a, 10b). [7] Locking head according to any one of claims 1 to 6, characterized by , that the telescopic bolt body (4) has guide surfaces (16) which are in contact with the housing (2) for guiding the telescopic bolt body (4). [8] Locking head according to any one of claims 1 to 7, characterized by , that the telescopic bolt body (4) has guide surfaces (16) which are in contact with a guide housing (15a, 15b) connected to the housing (2) for guiding the telescopic bolt body (4). [9] Locking head according to any one of claims 1 to 8, characterized by , that the cylinder chamber (9a, 9b) of the piston (10a, 10b) is arranged in a guide housing (15a, 15b) which is connected to the housing (2) of the locking head (1).

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