LOCKING HEAD

Description

[0001] The present invention relates to a locking head for extending and retracting telescopic booms, which can be used, for example, in telescopic boom cranes. Such locking heads typically have a yoke which, by hydraulic actuation, releases a locking bolt in the telescopic boom, so that the telescopic boom or a telescopic boom section of the telescopic boom is unlocked and can thus be moved.

[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. For this purpose, two corresponding bolts (so-called cylinder bolt bodies) are displaced, engaging with the telescopic section. The telescopic section, still coupled to the adjacent section, is then unlocked by activating a corresponding unlocking mechanism. It is known from the prior art that a spring-loaded bolt is pulled by means of a hydraulic actuation of a telescopic bolt body, allowing the telescopic section engaged with the locking head to be extended. Consequently, the locking head can now displace the telescopic section by means of the telescoping cylinder, extending the inner telescopic section. In the extended position, the telescopic section must first be re-locked with the adjacent telescopic section.For this to happen, the corresponding release claw (actuated by at least one telescopic bolt body) must be returned to its starting position so that the extended telescopic section is firmly connected to an adjacent telescopic section. Only when the two adjacent telescopic sections are locked together may the cylinder bolts between the locking head and the (extended) telescopic section be released. The telescoping cylinder then retracts to, if necessary, extend another telescopic section that has not yet been extended, in the manner described above.

[0004] The cylinder bolt or telescopic bolt is actuated by a hydraulic system that moves the respective bodies into the desired position. Extension or retraction can also be achieved using a spring element, so that if the hydraulic pressure decreases, the respective bodies retract back into or out of the locking head.

[0005] DE 20 2015 101 045 U1 discloses a locking head known from the prior art, the locking body of which can be moved in its position by means of hydraulics.

[0006] A disadvantage of such a locking head known from the prior art is that the locking head, which is arranged at the movable end of a telescopic cylinder, must have various hydraulic lines that enable appropriate control of the telescopic bolt body or the cylinder bolt body.

[0007] A locking head according to the preamble of claim 1 is known from JP 2017 159973 A.

[0008] The objective of the present invention is to provide a locking head that is lighter than the implementations known from the prior art and enables more economical operation.

[0009] This is achieved with a locking head that has all the features of claim 1. Advantageous embodiments of the locking head according to the invention are found in the dependent claims.

[0010] The locking head according to the invention for telescoping cylinders of a telescopic boom, which has several telescopic boom sections, comprises a housing, at least one bolt-shaped cylinder bolt body that can be extended and retracted from the housing to lock the locking head with a telescopic boom section, and at least one bolt-shaped telescopic bolt body that can be extended and retracted from the housing to release the telescopic boom section for a telescoping movement. The locking head is characterized by at least one electric actuator designed to actuate the at least one cylinder bolt body and / or the at least one telescopic bolt body.

[0011] By using an electric actuator, the need for hydraulic lines to the locking head, which are required to actuate the cylinder bolt body or the telescopic bolt body, is eliminated. This makes the overall system more cost-effective and lighter, which is particularly advantageous in light of the ongoing trend towards lighter components.

[0012] According to a further development of the invention, it can be provided that both the at least one cylinder bolt body and the at least one telescopic bolt body are equipped with a respective electric actuator.

[0013] It is not necessary for the cylinder bolt body and the telescopic bolt body to be driven by the same electric actuator, such as an electric motor. It would be conceivable for a coupling to transmit the force generated by the motor to the telescopic bolt body in one case and to the cylinder bolt body in a second, thus allowing the two bolt bodies to be actuated sequentially. As explained, each of the at least one cylinder bolt body and each of the at least one telescopic bolt body can have its own separate electric actuator, also enabling the two different bolt bodies to be actuated sequentially.

[0014] According to an optional modification of the present invention, it can further be provided that the locking head is also equipped with a spring element that pushes the at least one cylinder bolt body and / or the at least one telescopic bolt body in the extension or retraction direction.

[0015] Accordingly, the electric actuator can only be used to retract the cylinder bolt body or the telescopic bolt body. Therefore, a state in which at least one cylinder bolt body is retracted (and thus no longer coupled to a telescopic section) only occurs when this is actively achieved by energizing the electric actuator. Similarly, the retracted state of at least one telescopic bolt body (in which a telescopic section is no longer coupled to an adjacent telescopic section) can also only be actively achieved by energizing the electric actuator. If there is a malfunction in the electric actuator, the spring element ensures that the telescopic bolt body or the cylinder bolt body remains permanently in the position that poses the least risk.

[0016] According to the invention, the locking head is further provided with a magnetic element, in particular an electromagnetic element, which pushes the at least one cylinder bolt body and / or the at least one telescopic bolt body in the extension or retraction direction.

[0017] It can therefore be provided that the magnetic element is designed to push the cylinder bolt body or the telescopic bolt body in the extension or retraction direction.

[0018] In addition, according to the invention, the at least one electric actuator may be designed to move the at least one cylinder bolt body and / or the at least one telescopic bolt body in the retraction and / or extension direction. Typically, it may also be provided that, if a spring element or a magnetic element is present, the electric actuator can only move the telescopic bolt body or the cylinder bolt body in the direction opposite to the force exerted by the spring element or the magnetic element.

[0019] Additionally, it may be provided that the element for pushing in the direction of extension is designed to move the locking bolt body outwards even if the electric actuator fails and / or is not supplied with electrical power.

[0020] This ensures that even in the event of a malfunction of the electric actuator, for example the telescopic bolt body remains in its extended position, so that one telescopic section does not unlock from an adjacent telescopic section.

[0021] Furthermore, it may also be provided that the element for pushing in the direction of entry is designed to move the locking body outwards even if the electric actuator fails and / or is not supplied with electrical power.

[0022] This ensures that even in the event of a malfunction of the electric actuator, for example the cylinder bolt body remains in its retracted position, so that the locking head does not detach from a telescopic bolt.

[0023] According to a further variant encompassed by the invention, it can be provided that no hydraulic drive is used to move the at least one cylinder bolt body and / or the at least one telescopic bolt body.

[0024] Actuating the cylinder bolt body or the telescopic bolt body relies exclusively on the force generated by the electric actuator, whereby movement in the opposite direction can, of course, also be generated by the spring element or the magnetic element. Importantly, no hydraulic drive is required for movement, thus eliminating the need for the previously used technology and overcoming its associated disadvantages.

[0025] According to an optional embodiment of the invention, it can further be provided that the at least one cylinder bolt body and / or the at least one telescopic bolt body has a thread for engagement with a spindle driven by the electric actuator. The thread can run along an outer circumference of the bolt body or be located on an inner circumference of a blind hole. Furthermore, it can be provided that the electric actuator rotates an output shaft (for example, a spindle) via a gearbox or directly, which, by engaging the thread on the bolt body, causes a translational displacement of the bolt body.

[0026] Furthermore, according to the invention, it can be provided that at least one cylinder bolt body and at least one telescopic bolt body are provided, the respective axes of movement of which are not parallel to each other, preferably perpendicular to each other.

[0027] Typically, in a locking head, the angle between the axes of movement of a cylinder bolt body and a telescopic bolt body is 90°, so that the different bolt bodies have axes of movement that are perpendicular to each other.

[0028] Furthermore, it can be provided that at least two cylinder bolt bodies are provided, the respective axes of movement of which are parallel to each other, preferably identical to each other.

[0029] The at least two cylinder bolt bodies are typically located on opposite sides of the locking head housing. When these two cylinder bolt bodies are extended, they move away from each other. The direction of movement of the two cylinder bolt bodies is therefore antiparallel, but they may lie on a common axis.

[0030] Furthermore, according to an optional modification of the present invention, it can be provided that at least two telescopic bolt bodies are provided, the respective axes of movement of which are parallel to each other.

[0031] The at least two telescopic locking bolt bodies are located on a common side of the locking head housing and have parallel axes of movement. It is typical for the movement of the two telescopic locking bolt bodies to be approximately synchronous, as a type of clamp is usually attached between them, engaging a release mechanism. Retracting the two telescopic locking bolt bodies releases this mechanism, thus separating two adjacent telescopic sections.

[0032] The invention further relates to a telescopic cylinder with a locking head according to one of the variants discussed above.

[0033] It may be provided that only the electric actuator needs to be controlled to actuate the at least one cylinder bolt body and / or the at least one telescopic bolt body in the locking head, and preferably no hydraulic force is required.

[0034] Further features, details and advantages of the invention will become apparent from the following description of the single figure. This figure shows: Fig. 1: a schematic sectional view of a bolt body as it is formed in the locking head according to the invention.

[0035] Fig. 1 The figure does not show the entirety of a locking head, but merely an isolated area of ​​a bolt body 2 and its arrangement for moving the bolt body 2. It is clear to those skilled in the art that both the cylinder bolt body and the telescopic bolt body can be set in motion in the same way.

[0036] The locking mechanism 2 is therefore housed in the housing 1 and can optionally be extended from it or retracted into it.

[0037] The basic structure will be described below using the cylinder bolt body 2 as an example.

[0038] It can be seen that the bolt-shaped cylinder bolt body 2 is slidably received in the housing 1. The spring element 4 is designed such that it pushes the cylinder bolt body 2 outwards into an extended position. For movement in the opposite direction, i.e., inwards, an electric actuator 3 is provided, which interacts with the cylinder bolt body 2 by means of the rotation of a shaft 6, for example, a spindle, and moves it inwards into the interior of the housing 1. The cylinder bolt body 2 can thus have a blind bore facing the electric actuator 3, which has a threaded section on its inner circumference that meshes with a corresponding section of a shaft driven by the electric actuator 3.

[0039] It is clear to the expert that a threaded area may also be provided on the outer circumference of the cylinder bolt body, which interacts with a corresponding spindle of the electric actuator 3.

[0040] Reference numeral 5 designates the lines for controlling and supplying power to the electric actuator 3, which have much more compact dimensions and a significantly lower weight than conventionally used hydraulic lines. While it is not strictly necessary to place an electric actuator inside the locking head when using a hydraulic drive, the ongoing miniaturization of electrical components and actuators makes it possible to position it within the locking head, thus making the weight savings from eliminating the hydraulic lines a significant advantage.

[0041] The spring element 4 is designed to push the cylinder bolt body 2 outwards, so that even in the event of a failure or other defect of the electric actuator 3 the cylinder bolt body 2 remains in its extended position.

Claims

1. Locking head for a telescoping cylinder of a telescopic boom having a plurality of telescopic boom sections, comprising: a housing (1), at least one bolt-shaped cylinder locking bolt (2) which can be extended and retracted out of the housing (1) in order to lock the locking head to a telescopic boom section, at least one bolt-shaped telescoping locking bolt (2) which can be extended and retracted out of the housing (1) in order to release the telescopic boom section for a telescoping movement, and at least one electric actuator drive (3) which is designed to actuate the at least one cylinder locking bolt (2) and / or the at least one telescoping locking bolt (2), characterized by a magnetic element, in particular an electromagnetic element, which urges the at least one cylinder locking bolt (2) and / or the at least one telescoping locking bolt (2) in the extension or retraction direction.

2. Locking head according to claim 1, wherein both the at least one cylinder locking bolt (2) and the at least one telescoping locking bolt (2) are each provided with a respective electric actuator drive (3).

3. Locking head according to one of the preceding claims, further with a spring element (4) which urges the at least one cylinder locking bolt (2) and / or the at least one telescoping locking bolt (2) in the extension or retraction direction.

4. Locking head according to one of the preceding claims, wherein the at least one electric actuator drive (3) is designed to move the at least one cylinder locking bolt (2) and / or the at least one telescoping locking bolt (2) in the retraction and / or extension direction.

5. Locking head according to the preceding claim, wherein the element for urging in the extension direction is designed to move the locking bolt (2) outward even if the electric actuator drive (3) fails and / or is not supplied with electrical power.

6. Locking head according to one of the preceding claims, wherein no hydraulic drive is used for moving the at least one cylinder locking bolt (2) and / or the at least one telescoping locking bolt (2).

7. Locking head according to one of the preceding claims, wherein the at least one cylinder locking bolt (2) and / or the at least one telescoping locking bolt (2) has a thread for engagement with a spindle driven by the electric actuator drive (3).

8. Locking head according to one of the preceding claims, wherein both at least one cylinder locking bolt (2) and at least one telescoping locking bolt (2) are provided, the respective axes of movement of which are not parallel to one another, preferably are perpendicular to one another.

9. Locking head according to one of the preceding claims, wherein at least two cylinder locking bolts (2) are provided, the respective axes of movement of which are parallel to one another, preferably identical to one another.

10. Locking head according to one of the preceding claims, wherein at least two telescoping locking bolts (2) are provided, the respective axes of movement of which are parallel to one another.

11. Telescoping cylinder with a locking head according to one of the preceding claims.

12. Telescoping cylinder according to the preceding claim 11, wherein, for actuating the at least one cylinder locking bolt (2) and / or the at least one telescoping locking bolt (2) in the locking head, only the electric actuator drive (3) is to be controlled, and preferably no hydraulic force is required.