EP2218672B1 - Locking head - Google Patents

Description

The invention relates to a locking head for telescoping cylinder of a plurality of telescopic shots comprising crane jib.

The individual telescopic sections of a crane boom of a mobile crane are successively extended by means of a telescoping cylinder and locked together in the extended position. For this purpose, a locking head is required, which fulfills two functions. Before a telescopic section can be moved, it must be coupled with the locking head. For this purpose, two cylinder latch are extended, which come into engagement with the telescopic section. Subsequently, the still coupled with the adjacent telescopic section telescopic arm is unlocked by a corresponding unlocking mechanism is activated. For example, a spring-loaded bolt is pulled by means of a latch claw. Now, the locking head is displaced by means of the telescoping cylinder, so that the inner telescopic section is extended. In the approached position, the telescopic section must first be locked again with the adjacent telescopic section. For this, the locking claw must be returned to its original position. Only when the two adjacent telescopic shots are locked together, the cylinder latch between the locking head and the telescopic section may be released again. Subsequently, the telescoping cylinder retracts to possibly displace another telescopic section in the manner described above.

Decisive for the reliability is reliable control of the two locking mechanisms. In this context, for example, in the EP 0 754 646 B1 a system has been proposed in which the mechanisms are combined in such a way that a release of a two adjacent telescopic shots summarizing locking bolt is possible only when the cylinder locks are set and the cylinder latch are disengaged only when the released locking bolt after completed stroke again is set.

The DE 196 41 193 A1 discloses a telescopic boom, which is particularly intended for stationary or mobile cranes. The individual telescopic shots are locked by bolt connections, which are released or set via a holding device. This provides for this purpose a locking claw, which is brought into engagement with the locking pins to be manipulated. The holding device is mounted on a cylinder, wherein the individual shots are retracted and extended by the cylinder stroke in combination with a deflected rope drive. The movable holding device is for this purpose coupled via laterally extendable securing bolt with the auszufahrenden shot, which is connected in its end position by a set over the locking claw locking bolt with the previous shot.

The structure of such a locking head is due to the very limited space within the telescopic arm usually so that the plane in which the hydraulic means for actuating the locking claw in the axial direction of the telescoping cylinder are offset to that plane in which the cylinder locks are arranged. This axial offset leads to a considerable length and thus to a considered disadvantageous, relatively large volume with a corresponding mass of such a locking head. Another disadvantage is that locking bolt, which should block the movement of the cylinder bolt when the locking claw retracted, naturally have to be spatially in the same plane as the cylinder latch, with the result that the translational drive for the locking claw is outside the plane of movement of the cylinder bolt. As a result of this, a bending moment is introduced into the locking claw due to the drive applied decentrally to the locking claw.

Another disadvantage is that with increasing diameter of the piston rod of the telescoping cylinder and the distance of the actuating piston for the locking claw must be larger. While the actuating piston is a standard component, a latching claw is generally a complex cast component, which must be manufactured and machined at different distances between the actuating pistons in different sizes. The manufacturing effort is undesirably high as well as the variety of parts.

The invention is based on the object to show a locking head whose measured length measured in the axial direction of the telescoping cylinder is reduced as far as possible and which is also possible to produce as inexpensively.

This object is achieved by a locking head having the features of patent claim 1.

Advantageous developments of the inventive concept are the subject of the dependent claims.

The locking head according to the invention for telescoping cylinders of a crane telescope comprising a plurality of telescopic sections comprises a housing and in the housing translationally displaceable cylinder latch for locking the locking head with a telescopic section, if this is to be relocated. Further, a locking claw is provided, which is also displaceable relative to the housing and serves to actuate the unlocking of successive telescopic shots. The locking claw is transversely to the Zylinderriegeln and transversely displaceable to the telescoping cylinder. The locking claw is guided in the housing via a guide arranged circumferentially of the locking claw. The locking claw itself is thus performed directly in the housing.

In the latch claw occurs in the context of the invention, a central force application, via a collar on which arranged in the housing Entriegelungskolben act, which shift the collar and thus the locking claw against a spring force from a starting position into an unlocked position. The Entriegelungskolben, which are also referred to as plunger, can be arranged extremely space-saving directly in the housing, which has corresponding piston bores for receiving the plunger for this purpose. The frictional forces to which the locking claw is exposed are only reduced to the low friction in the area of the sealing points of the unlocking piston. The friction losses are thus minimal.

In the case of a circumference region designed in the shape of a cylinder jacket, but also in peripheral regions of another cross-sectional contour, for example a rectangular peripheral region, the unlocking pistons necessary for the displacement can be arranged diametrically relative to the center of the locking claw. In order to avoid tilting of the locking claw in the housing, at least two unlocking pistons are provided, which act on the outwardly directed collar of the locking claw. The provision of the locking claw in the starting position can be done by two separate return springs, which are also arranged diametrically, preferably offset from the unlocking piston. In principle, it is also possible to provide only a central return spring in the housing, which is arranged centrally below the latch claw. As a result, the production cost can be further reduced.

There are no displacement means placed far outside of the force application point of the locking claw necessary, with the result that much smaller moments are introduced into the locking claw, so that it can be made more compact. In addition, it is no longer necessary vorzuhalten different sizes of locking claws, since the size of the locking claw within certain limits regardless of the diameter of the telescoping cylinder and thus is independent of the rest of the design of the housing of the locking head.

Due to the compact design and the leadership of the locking claw directly in the housing is compared to known designs a weight saving of about 50% possible. The main advantage, however, is a shorter installation dimension of the locking head, which can also reduce the length of the telescoping cylinder. But a shorter telescoping cylinder also means that the basic length of the boom can be reduced, which in turn means a weight saving.

In addition, existing locking heads can be replaced by the locking head according to the invention shorter design.

In an advantageous embodiment, the leadership of the locking claw in the same transverse to the telescoping cylinder transverse plane is arranged as the cylinder latch. In this case, the overall length can be reduced to a minimum. In addition, all force application points, be it by forces that occur by moving the locking claw or by setting the cylinder latch, reduced to the smallest space. Significantly fewer moments are introduced into the housing, which also has a positive effect on the housing structure.

The type of leadership of the locking claw plays a minor role in terms of leadership geometry. The guide can therefore basically be formed by a plurality of individual guide sections. However, it is considered to be particularly advantageous if the outer peripheral region of the locking claw is shaped like a cylinder jacket. This is in particular the height range of the diametrically arranged claw projections, which are guided directly in the housing. A cylinder jacket-shaped design of the peripheral region of the locking claw manufacturing technology by machining economically and with high precision feasible. The leadership properties are naturally outstanding because of the large-area leadership, since the mutually supporting guide surfaces are sized accordingly large.

Since, for reasons of operational reliability, the cylinder latches may only be displaced as a function of the position of the latch claw, it is provided in an advantageous development that a safety bolt connected to the latch claw or in operative engagement blocks the stroke of a cylinder bolt, when the latch claw retracted and the cylinder latch are extended and that the safety bolt releases this stroke when the latch claw is extended. This relationship is known as such. What is new, however, is that the securing bolt does not necessarily have to be firmly connected to the locking claw, but can also be in operative engagement only with it. In an advantageous embodiment, it is possible to make the direction of displacement of the securing bolt differ from the direction of displacement of the locking claw. This is only possible if the safety pin can shift relative to the latch claw. In an advantageous embodiment, therefore, a wedge surface is provided on the locking claw on which the securing bolt is supported and displaced in the direction of the cylinder bolt when the cylinder bolt are extended and the locking claw retracted.

It is considered to be particularly useful when the latch drive for the cylinder latch comprises a rack which meshes with pinion portions of the cylinder latch via pinions so that the cylinder bolts are synchronously displaceable in opposite directions. In this variant, the cylinder latch are consequently not acted upon directly hydraulically, so that the space behind the extended cylinder latch is free of hydraulic fluid. This in turn has the advantage that the securing bolt when moving the locking claw in the unlocked position does not have to be sealed in a special way against the space behind the cylinder latch. This eliminates further sealing surfaces and sealants. The machining of the locking head is simplified and reduces friction. Also, the cylinder latch itself need not be sealed against the escape of hydraulic fluid.

It is provided in the context of the invention that the bolt drive is arranged on the side facing away from the latch claw of the housing. In this way, the space on the circumference of the piston rod of the telescoping cylinder available space is optimally utilized. A particular advantage of the central latch drive is that only one safety bolt must block one of the cylinder locks, which also contributes to weight savings. When it is ensured that a cylinder latch in blocked his movement, the other cylinder latch can not be relocated due to the mutual teeth of the bolt drive.

The displacement of the rack itself is expediently counter to a spring force of a return spring, by means of a piston pin acting on the rack, which is also arranged in encapsulated construction in the housing. This also allows a considerably simplified installation and reduced installation costs. Another positive aspect is that relatively large spaces are present within the locking head, so that no vent valves for the locking head are necessary.

Another advantage is that a simplified position sensing via sensors is possible, which have been necessary in known solutions so far on both Zylinderriegeln. Due to the rack and pinion drive, it is sufficient to interrogate the position of the toothed rack or the piston pin acting on the toothed rack via a sensor.

Overall, the locking head according to the invention is characterized by a significantly reduced probability of leakage and thus increased reliability, which is reflected in a reduced maintenance. Remarkable are the minimization of the necessary sealing means and thus also the reduction of friction losses. With the invention, it has been possible to show a functionally reliable locking head in an extremely compact design, which solves the task underlying the invention very elegantly.

Figur 1

einen Querschnitt entlang der Linie I-I der Figur 3 durch einen Verriegelungskopf bei eingefahrenen Zylinderriegeln;

Figur 2

den Verriegelungskopf im Querschnitt entlang der Linie II-II der Figur 4 bei ausgefahrenen Zylinderriegeln, wobei sich die Riegelklaue in einer Entriegelungsstellung befindet;

Figur 3

den Verriegelungskopf der Figur 1 in der Draufsicht und

Figur 4

den Verriegelungskopf der Figur 2 in der Draufsicht.

The invention will be described below with reference to the FIGS. 1 to 4 illustrated embodiment illustrated. It shows:

FIG. 1

a cross section along the line II of FIG. 3 by a locking head with retracted cylinder locks;

FIG. 2

the locking head in cross section along the line II-II of FIG. 4 with extended Zylinderriegeln, wherein the latch claw is in an unlocked position;

FIG. 3

the locking head of FIG. 1 in plan view and

FIG. 4

the locking head of FIG. 2 in the plan view.

FIG. 1 shows a locking head 1 in cross section along the line II of FIG. 3 , The locking head 1 is attached in a manner not shown to a telescopic cylinder of a plurality of telescopic shots comprising crane jib. The locking head 1 comprises a housing 2, in which translationally displaceable cylinder bars 3, 4 are arranged. The cylinder latch 3, 4 are extendable in opposite directions from the housing 2 and serve to lock the locking head 1 with a telescopic arm to carry this when retracting or extending the Teleskopierzylinders. With the Zylinderriegeln 3, 4 of the locking head 1 and thus the telescoping cylinder is locked with the Teleskopschüssen. This unit can be called a cylinder lock (ZV).

Transverse to the cylinder locks 3, 4, a locking claw 5 within the housing 2 is displaced. The locking claw 5 serves to grasp an unlocking pin not shown in detail and to pull in the direction of the housing 2, whereby the locking of two adjacent telescopic sections is canceled, with the result that the inside telescopic section, for this purpose on the cylinder latch 3, 4th locked with the locking head 1, can be carried. The locking claw 5 is part of the so-called telescopic lock (TV).

In the inventive locking head 1, the locking claw 5 is guided circumferentially in the housing 2. From the representation of FIG. 1 is the standing in a starting position latch claw 5 can be seen, which closes with its upper edge to the housing 2. The locking claw 5 has two diametrically arranged claw projections 6, 7, by which a T-shaped undercut is formed. This undercut serves to receive a bolt head of an unlocking bolt, which engages in the process of the locking head 1 in the longitudinal direction of the telescoping cylinder in this undercut. The locking claw has in the height range of its diametrically arranged claw projections 6, 7 an outer peripheral portion 8, which is guided directly in the housing 2 becomes. The belonging to this peripheral region 8 wall 9 of the housing 2 forms together with the locking claw 5 a guide 10 for the locking claw. 5

The locking claw 5 has at its lower end an outwardly projecting collar 11, on which unlocking pistons 12, 13 act. The unlocking pistons 12, 13 are designed as plungers, wherein the corresponding piston bores are formed in the housing 2 itself. About not shown channels within the housing 2, the Entriegelungskolben 12, 13 acted upon by a hydraulic medium and in the in FIG. 2 illustrated manner shifted downwards in the direction of the cylinder lock ZV. The displacement takes place here against a spring force F, which starts from a return spring 14. Upon release of the unlocking piston 12, 13, the spring force F acts on the underside shown in the image plane 15 of the latch claw 5 and moves it back from the unlocked position ( FIG. 2 ) to the starting position ( FIG. 1 ).

However, a displacement of the latch claw 5 is only possible if the cylinder latch 3, 4 are extended, as in FIG. 2 is shown. For this purpose, a downwardly projecting securing bolt 16 is provided in a first embodiment of the locking claw 5, which engages behind this extended cylinder bolt 3 and thereby at the same time blocks the re-retraction of the cylinder bolt 3.

As an alternative to the fixedly connected to the locking claw 5 securing bolt 16 is in the FIGS. 1 and 2 in the image plane right an alternative locking pin 17 shown. The locking pin 17 has a different orientation than the securing bolt 16. It is at an angle to the marked as A and B displacement directions of the locking claw 5 and the cylinder latch 3, 4. The displacement directions A, B are perpendicular to each other. The securing bolt 17 is displaced in the direction of the double arrow (displacement direction C). As based on the FIG. 2 can be seen, engages a lower end 18 of the locking bolt 17 in a pocket 19 of the cylinder bolt 3 when the cylinder latch 3 is extended. In this position, the locking claw 5 can be retracted, so that the locking pin 17 is no longer back in Direction of the latch claw 5 can shift. As a result, the cylinder lock 3 is blocked in its movement.

The reverse situation is in FIG. 1 shown. There, the cylinder latch 3 is in the retracted position, so that the lower end 18 of the securing bolt 17 is lifted out of the pocket 19 and thus projects into the lifting region of the latch claw 5. In this position, the locking claw 5 can not be retracted, since the securing bolt 17 is supported at a corner 20 of the locking claw 5. The corner 20 is designed for this purpose as a wedge surface 21, which allows sliding of the securing bolt 17 on the latch claw 5. In the same way, the pocket 19 is bevelled in the cylinder latch 3, so that the securing bolt 17 without spring elements forcibly guided either in the in FIG. 1 shown position or alternatively in the in FIG. 2 shown position can be transferred.

Another advantage of the locking head 1 according to the invention is that only a single such securing pin 16, 17 is required because the cylinder latch 3, 4 are positively coupled with each other in their oppositely oriented movement. This coupling takes place via a latch drive 22 whose core component is a toothed rack 23. About pinion 24, 25 are the rack 23 and rack sections 26, 27 of the cylinder latch 3, 4 in engagement. When the rack 23 is translationally displaced, the pinions 24, 25 rotate, so that the cylinder latch 3, 4 on their rack sections 26, 27 retracted or extended. The displacement of the rack 23 by means of a piston pin 28 which is coupled to the rack 23. The displacement of the piston pin 28 takes place against a spring force F1, which starts from a return spring 29. For determining the position of the cylinder bolt 3, 4, it is sufficient if the position of the piston pin 28 is determined by sensors 30 which indicate a control system, not shown, whether the cylinder latch 3, 4 are extended or retracted.

The position determination of the locking claw 5 is likewise effected via sensors 31. For this purpose, a corresponding projection 32 can be formed on the locking claw 5, which approaches the sensors 31 in the starting position or in the unlocking position ( FIGS. 3 and 4 ).

The FIGS. 3 and 4 show top views of the locking head 1, wherein in the FIG. 3 the cylinder latch 3, 4 are retracted and in FIG. 4 are extended. It is clear from this representation that the transverse plane designated QE, which corresponds to the sectional plane II or II-II, coincides with the longitudinal axis of the cylinder latches 3, 4 and at the same time intersects the center of the latch claw 5. In addition, it can be seen that the locking claw 5 is designed with respect to its outer peripheral portion 8 cylinder jacket-shaped. The guide 10 of the locking claw 5 formed by the peripheral region 8 and the wall 9 of the housing 2 is located centrally in the housing 2, so that no moments are introduced into the locking claw 5 when the unlocking bolt is not shown. The central position of the latch claw 5, combined with the diametrically arranged unlocking piston 12, 13 and the central guide 10 of the latch claw 5 allow an extremely compact design and thus a significant reduction in length over older designs.

From the FIGS. 3 and 4 it can be seen that a projection 32 is arranged on the latch claw 5 in order to be able to indicate to the associated sensor 31 the position of the latch claw 5.

Reference numerals:

1 -

locking head

2 -

casing

3 -

cylinder bolt

4 -

cylinder bolt

5 -

locking claw

6 -

claws lead

7 -

claws lead

8th -

peripheral region

9 -

wall

10 -

guide

11 -

collar

12 -

unlocking

13 -

unlocking

14 -

Return spring

15 -

bottom

16 -

safety bolt

17 -

safety bolt

18 -

The End

19 -

bag

20 -

corner

21 -

wedge surface

22 -

lock drive

23 -

rack

24 -

pinion

25 -

pinion

26 -

Rack section

27 -

Rack section

28 -

piston pin

29 -

Return spring

30 -

sensor

31 -

sensor

32 -

head Start

A -

Direction of displacement v. 5

B -

Direction of displacement v. 3, 4

C -

Direction of displacement v. 17

F -

Restoring force

F1 -

spring force

QE -

transverse plane

Claims (9)

1. A locking head for telescopic cylinders of a crane jib comprising multiple telescopic stages, having a housing (2) and having cylinder bolts (3, 4) displaceable translationally in the housing (2) for locking the locking head (1) with one telescopic stage and having a locking claw (5) displaceable relative to the housing (2) for actuating unlocking of successive telescopic stages, the locking claw (5) being displaceable transversely of the cylinder bolts (3, 4) and transversely of the telescopic cylinders and being guided in the housing (2) by way of a guide (10) arranged circumferentially of the locking claw (5), characterised in that the locking claw (5) comprises a collar (11), on which act hydraulically actuatable unlocking pistons (12, 13) arranged in the housing (2), for displacement of the locking claw (5) from a starting position into an unlocking position, the unlocking pistons (12, 13) being diametrically arranged.
2. A locking head according to claim 1, characterised in that the guide (10) is arranged in the same transverse plane (QE) extending transversely of the telescopic cylinder as the cylinder bolts (3, 4).
3. A locking head according Lo claim 1 or claim 2, characterised in that, at the level of its diametrically arranged claw projections (6, 7), the locking claw (5) comprises an outer circumferential region (8) which is a component part of the guide (10).
4. A locking head according to claim 3, characterised in that the outer circumferential region (8) Lakes Lhe form of a cylinder envelope.
5. A locking head according to any one of claims 1 to 4, characterised in that a securing pin (16, 17) connected of in active engagement with the locking claw (5) blocks the stroke path of a cylinder bolt (3) when the locking claw (5) is retracted and the cylinder bolts (3, 4) extended, and in that the securing pin (16, 17) opens up the stroke path when the locking claw (5) is extended.
6. A locking head according to claim 5, characterised in that the direction of displacement (C) of the securing bolt (17) is at an angle to the direction of displacement (A) of the locking claw (b) and at an angle to the direction of displacement (B) of the cylinder bolts (3, 4), a wedge face (21) being situated on the locking claw (b), on which wedge face the securing bolt (17) rests and is displaced in the direction of the cylinder bolt (3), when the cylinder bolts (3, 4) are extended and the locking claw (5) retracted.
7. A locking head according to any one of claims 1 to 6, characterised in that a bolt drive (22) comprises a toothed rack (23), which is engaged via pinions (24, 25) with toothed rack portions (26, 27) of the cylinder bolts (3, 4), the cylinder bolts (3, 4) being synchronously displaceable in opposing directions.
8. A locking head according Lo claim 7, characterised in that the bolt drive (22) is arranged on the side of the housing (2) remote from the bolt claw (5).
9. A locking head according Lo either one of claims 7 or 8, characterised in that a piston pin (28) acting on the toothed rack (23) is arranged in the housing (2) in order to displace the toothed rack (23) of the bolt drive (22) against the spring force (F1) of a restoring spring (29).

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