Cranes and methods
The introduction of a length-adjustable retaining stay with lift elements simplifies the folding mechanism of cranes, enabling space-efficient parking and maintaining operational functionality.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- LIEBHERR WERK NENZING
- Filing Date
- 2025-11-18
- Publication Date
- 2026-06-02
AI Technical Summary
Conventional cranes require complex modifications or have a more complex structure to achieve a folding function, limiting their space-saving capabilities in urban areas.
Incorporating a length-adjustable retaining stay with lift elements, such as hydraulic or electric cylinders, to facilitate the folding of the luffing jib against the main boom, allowing for a simple and efficient folding mechanism.
Enables cranes to be parked in a space-saving manner without altering their base structure, maintaining all conventional functions, and ensuring safe operation through locking mechanisms.
Smart Images
Figure 2026090222000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a crane, particularly a mobile crane, comprising a main boom, a luffing jib pivotally connected to the main boom, and a retaining stay extending between the main boom and the luffing jib.
Background Art
[0002] For example, particularly in urban areas, it is known that the space conditions for installing (erecting) a crane such as a crawler crane at a construction site and positioning it at the working position are often limited. Under such limited space conditions, it is often impossible to realize the general parking positions of conventional cranes such as the general installation of the crane and the folded position (jackknife position) of the boom device of the crane.
[0003] Therefore, in many cases, it is necessary to enable the crane to have a folding function by allowing the luffing jib of the crane to be completely abutted (adhered) against the main boom of the crane in the installed state. For example, with the main boom installed, the luffing jib is lowered daily and arranged in a vertical parking position so that the crane can be parked in a space-saving manner, for example, at night.
[0004] For this purpose, it is known to incorporate a cable hoist with a plurality of pulley devices in the support stay between the main boom and the luffing jib so that the luffing jib can be completely lowered to the vertical position. For this, a specific main boom head that supports this folding mechanism is required.
Summary of the Invention
Problems to be Solved by the Invention
[0005] Thus, conventional cranes can only be modified to have the aforementioned folding function through complex modifications, and / or cranes with the aforementioned folding function have a more complex structure than conventional cranes.
[0006] Given this background, the object of the present invention is to improve the aforementioned crane, particularly in terms of its simple structure and / or modifications. [Means for solving the problem]
[0007] This objective is achieved by subject matter having the features of independent claim 1. A preferred development of the present invention is the subject matter of the dependent claim.
[0008] Therefore, according to the present invention, it is proposed to make the length of the retaining stay changeable by providing a lift element of changeable length to the retaining stay.
[0009] Preferably, the retaining stay comprises a lift element and a main strand, such as one or more steel ropes, a steel stay rod and / or a CFRP stay rod, and the lift element and the main strand are connected via an adapter.
[0010] A luffing jib is also called a luffing needle.
[0011] The main boom and luffing jib are preferably components of the boom apparatus.
[0012] The crane is preferably a mobile crane, especially a crawler crane.
[0013] The crane preferably has adjustable retaining stays for the luffing mechanism of the crane's luffing jib.
[0014] The crane may have multiple lifting elements arranged in parallel.
[0015] The lifting element is preferably a hydraulic lifting element, particularly a hydraulic cylinder, or an electric lifting element, particularly a linear actuator.
[0016] Preferably, the lift element is a lift element that is driven by hydraulics and / or electric power.
[0017] Preferably, the retaining stays are extendable, and as a result, the luffing jib is configured to pivot relative to the main boom so that the luffing jib contacts the main boom.
[0018] In other words, preferably, the main boom and luffing jib are configured to be foldable.
[0019] Preferably, the retaining stay has one end attached to the lower or upper portion of the main boom when the main boom is in a vertical position, and the lift element is positioned at that end of the retaining stay.
[0020] Alternatively, the lift element may be positioned or attached, for example, to the boom head, i.e., the upper part of the main boom.
[0021] Preferably, the retaining stay includes a locking means configured to lock the lift element, particularly in the retracted position (storage position), and is configured to prevent the lift element from extending.
[0022] Preferably, the locking means includes or is composed of hydraulic elements, particularly hydraulic cylinders, or electric elements, particularly linear actuators.
[0023] Preferably, the lift element includes a housing and a piston rod that is extendable from the housing and retractable (stored) within the housing.
[0024] The adapter may also be part of the piston rod.
[0025] Preferably, one or more locking lugs each having an opening are arranged on the housing, the piston rod has an opening, a locking element, particularly a locking bolt, is provided, and the locking element is configured to be inserted through the opening of one locking lug or the openings of a plurality of locking lugs and the opening of the piston rod when the openings are aligned, so as to lock the lift element in the storage position. The locking means is configured to include one or more locking lugs and the locking element.
[0026] Preferably, the adapter of the piston rod has an opening.
[0027] Preferably, the locking means includes monitoring means, particularly an electromechanical switch or a proximity switch, and is configured to detect the position of the locking means, particularly the locking element.
[0028] The present invention also relates to an operation method of a crane according to the present invention. Shortening the holding stay by shortening the lift element and swinging the luffing jib outward from the main boom by an initial opening angle. Locking the lift element.
[0029] Preferably, first lift the main boom and the luffing jib in contact therewith from the horizontal position to the vertical position.
[0030] Preferably, after the crane is first brought to a state where the main boom is in the vertical position and the luffing jib is pivoted by an initial opening angle with respect to the main boom, by releasing one or more locks of the lift element and / or by extending one or more of the lift elements, extend the holding stay and pivot the luffing jib inward (pivot toward the inside) by an initial opening angle with respect to the main boom so that the luffing jib abuts against the main boom, thereby bringing the crane to the parking position.
[0031] Preferably, the main boom and the luffing jib in contact with it are then lowered from a vertical position to a horizontal position.
[0032] Furthermore, the present invention relates to a method for retrofitting a crane having a main boom, a luffing jib rotatably connected to the main boom, and a retaining stay extending between the main boom and the luffing jib, characterized in that one or more length-adjustable lift elements are incorporated into the retaining stay to make the crane into the crane according to the present invention.
[0033] Preferably, the retaining stay has one or more retaining elements whose length can be changed, thereby allowing the length (length of the retaining stay) to be changed and enabling the retrofitting of conventional cranes.
[0034] It is preferable that the entire existing boom assembly of the crane to be retrofitted can be retained as is. It is preferable that the crane according to the present invention has the same base body as a conventional crane.
[0035] When retrofitting a conventional crane, it is preferable that all conventional functions, such as lifting (hoisting) operation by the main boom, two-hook operation, runner operation, and the use of the entire needle portfolio, remain available. Furthermore, it is desirable that newly manufactured cranes according to the present invention, i.e., cranes not formed by retrofitting a conventional crane, also possess these functions.
[0036] Preferably, the extension of the retaining stays can be enabled by one or two lifting elements driven hydraulically and / or electrically. It is preferable that the entire existing boom equipment, and therefore the existing machine that forms the base of the conventional crane, can continue to be used. Therefore, it is preferable that the base machine does not change. It is preferable that all conventional functions, such as lifting operation by the main boom, two-hook operation, runner operation, and use of the entire needle portfolio, be maintained. It is preferable that the folding function can be retrofitted to the current level.
[0037] When the luffing jib is in contact with the main boom, it is preferable that the luffing jib can be connected to the main boom.
[0038] Here, the terms “one” (ein and eine) refer to one possible embodiment, but may also refer to multiple elements and not necessarily strictly to a single element. Similarly, the use of the plural form includes the existence of the singular form of the corresponding element, and conversely, the singular form includes the existence of multiple corresponding elements. Furthermore, all features of the invention described herein may be combined with each other as needed, or asserted independently of each other.
[0039] Further advantages, features, and effects of the present invention will become apparent from the following description of preferred embodiments made with reference to the drawings. In the drawings, identical or similar components are denoted by the same reference numerals. The drawings are as follows. [Brief explanation of the drawing]
[0040] [Figure 1] Figure 1 is a side view of an embodiment of the crane according to the present invention. [Figure 2] Figure 2 is a side view of an embodiment of the crane according to the present invention. [Figure 3] Figure 3 shows a detailed side view of the embodiment of the crane according to the present invention shown in Figure 2. [Figure 4]Figure 4 is a side view of an embodiment of the crane according to the present invention. [Figure 5] Figure 5 shows a detailed side view of the embodiment of the crane according to the present invention shown in Figure 4. [Figure 6] Figure 6 is a side view of an embodiment of the crane according to the present invention. [Figure 7] Figure 7 is a perspective view showing details of an embodiment of the crane according to the present invention. [Figure 8] Figure 8 is a side view showing details of an embodiment of the crane according to the present invention. [Modes for carrying out the invention]
[0041] Figure 1 shows a crawler crane type crane 10 equipped with a main boom 1 and a luffing jib 2. The luffing jib 2 is rotatably connected to the main boom 1. A retaining stay 3 extends between the main boom 1 and the luffing jib 2. The main boom 1 and the luffing jib 2 are the main components of the boom apparatus of the crane 10.
[0042] The main strands of the retaining stay 3, such as one or more steel ropes, steel stay rods, and / or CFRP stay rods, are connected to the lift element 30 via adapters.
[0043] The luffing jib 2 has a luffing mechanism 20 comprising a lower A-frame 21 and an upper A-frame 22. The luffing mechanism 20 allows the entire luffing jib 2 to be rotated or tilted. The luffing mechanism 20 may also be called a needle retraction mechanism.
[0044] The retaining stay 3 is fixed to the lower part of the main boom 1 and the free end of the lower A frame 21.
[0045] Figure 1 shows the assembled crane 10 in its parked (standby) position, with the boom unit placed on the ground and in a horizontal position. The luffing jib 2 is in full contact with the main boom 1. In this way, the main boom 1 and luffing jib 2 are folded.
[0046] The position of the crane 10 shown in Figure 1 is the state seen after the crane 10 has been assembled or after the boom device has been fully lowered. To enable this position, the retaining stay 3 is extendable. This extension can be made possible by one or two lifting elements in the retaining stay 3 that are hydraulically and / or electrically driven. In this embodiment, the retaining stay 3 has strictly one lifting element. The crane 10 may have multiple lifting elements, for example, two lifting elements arranged in parallel. In this embodiment, the lifting elements are hydraulic cylinders. In the position of the crane 10 or boom device shown in Figure 1, the amount of extension required for the retaining stay 3 is maximum. The lifting elements are in the fully extended state.
[0047] In the parking position of the crane 10 shown in Figure 1, the retaining stay 3 can be opened (unloaded), and the lift element 30 can be placed on the main boom 1. In this case, the lower A frame 21 is secured by a chain.
[0048] The lift element 30 can also be separated from the adapter and retracted. The adapter is fixed in place.
[0049] Figure 2 shows the crane 10 with its boom unit raised, with the main boom 1 and luffing jib 2 either vertically upright or folded vertically and aligned. The position shown in Figure 2 is the state seen after the boom unit has been lifted or before it is lowered to a horizontal parking position after work is completed. In the position of the crane 10 or boom unit shown in Figure 2, the required extension of the retaining stay 3 is at its maximum. One or more lift elements are in the fully extended state.
[0050] Frames A 21 and 22 exhibit an angle α1 corresponding to the arrangement of the boom.
[0051] The required length of the lift element 30 varies depending on the boom's configuration.
[0052] In this vertical position, the main boom 1 exhibits an angle between 88° and 90° with respect to the ground.
[0053] In Figure 2, detail I is enclosed in a circle, which is then enlarged and displayed in Figure 3.
[0054] In Figure 3, the lift element 30 of the retaining stay 3 is shown in its extended position, with the piston rod 32 of the lift element 30 fully extended from the housing 31 of the lift element 30. The lift element 30 is a hydraulic cylinder. The housing 31 is attached to the main boom 1, and the piston rod 32 is attached via an adapter to the main strand of the retaining stay 3, which leads to the luffing jib 2, for example, one or more steel ropes, steel stay rods and / or CFRP stay rods.
[0055] The lift element 30 incorporated into the retaining stay 3 shortens the retaining stay 3 to its working length, causing the luffing jib 2 to rotate relative to the main boom 1 until the luffing jib 2 is at an initial opening angle α3 relative to the main boom 1. This raises the luffing jib 2 to the α3 position, preparing it to swing further outward, as is evident from Figure 4. The angle α1 between the A-frames 21 and 22 remains unchanged during this process.
[0056] Figure 4 shows the crane in the starting position for swinging the luffing jib 2 further outwards.
[0057] In Figure 4, detail section II is enclosed in a circle, which is then enlarged and displayed in Figure 5.
[0058] Figure 5 shows the state in which the lift element 30 of the retaining stay 3 is in the retracted position. The piston rod 32 of the lift element 30 is fully retracted into the housing 31 of the lift element 30.
[0059] At this position of the lift element 30, the retaining stay 3 has reached its operating length. The lift element 30 is in its fully retracted state. In this retracted position, the lift element 30 can be fixed by the locking mechanism. The required extension or retraction amount of the retaining stay 3 is determined as a result of the luffing jib 2 moving from the vertical position to an opening angle α3 = 30°.
[0060] Subsequently, the luffing jib 2 swings further by the luffing mechanism 20, as before. While the luffing jib 2 swings further outward, the angle α1 between the A-frames 21 and 22 decreases to its maximum value α2. During the luffing jib 2's inward swing, the angle α2 between the A-frames 21 and 22 increases to its maximum value α1. The angle between the lower A-frame 21 and the main boom 1 remains unchanged during this process.
[0061] Figure 6 shows the luffing jib 2 swinging outward to its maximum extent at an angle α2 between A-frames 21 and 22.
[0062] Figure 6 shows the crane 10 in the working position, where in this example the luffing jib 2 swings outward to its maximum angle, and the angle between the A-frames 21 and 22 is α2. The entire uprighting process is complete, and the crane 10 is ready for operation.
[0063] In the position shown in Figure 6, the retaining stay 3 cannot change its working length due to its lock. The lift element 30 is fully retracted and locked.
[0064] The sequence of operations from Figure 1 to Figure 6 shows the process of raising the boom device, and the sequence of operations from Figure 6 to Figure 1 shows the process of lowering the boom device.
[0065] In Figure 7, part of the locking mechanism that can lock the lift element 30 in the retracted position is shown in the form of two lock lugs 33 positioned (screwed in this example) on the housing 31 of the lift element 30. The lock lugs 33 may be welded. The lock lugs 33 are attached to the main strand-side end of the retaining stay 3 in the housing 31.
[0066] In Figure 7, the piston rod 32 is fully retracted and has an adapter with a coupling lug 34 that connects the piston rod 32 to the main strand of the retaining stay 30 which is connected to the luffing jib 2.
[0067] Each lock lug 33 and coupling lug 34 is provided with an opening. When these openings are aligned, that is, when the piston rod 32 is fully retracted into the housing 31, the lock bolt 35 can be passed through these openings as shown in Figure 8.
[0068] In other words, Figures 7 and 8 show the connection of the main strand of the retaining stay 3 to the lift element 30 in the locked position. At least one locking lug 33 is fitted to the housing 31 of the lift element 30, allowing the piston rod 32 to be locked against unintended extension.
[0069] Figure 8 shows additional lugs 36 of the adapter between the main strand of the retaining stay 3 and the lift element 30. These lugs 36 are securely connected by cotter pins 37.
[0070] The position of the lock bolt 35 is monitored by a monitoring device. This monitoring device can confirm whether the lock is open or closed, that is, whether the lock bolt 35 has penetrated all the openings.
[0071] If the piston rod 31 of the lift element 30 is not locked by the lock bolt 35, i.e., in the open state, the crane will not be able to lift. The crane will maintain the "assembled" operating state until it is confirmed that the lock is properly engaged. In the "crane operation" or "crane lifting operation" operating state, the lock bolt 35 cannot be unlocked. To unlock it, it is first necessary to switch back to the "assembled" operating state. Monitoring can be performed using an electric toggle switch and / or proximity switch as monitoring means. This configuration ensures that the length of the retaining stay 3 cannot be changed during the crane's lifting operation.
Claims
1. A crane, particularly a mobile crane, having a main boom and a luffing jib rotatably connected to the main boom, wherein a retaining stay extends between the main boom and the luffing jib, The crane is characterized in that the length of the retaining stay can be changed by providing a lift element of changeable length.
2. In the crane according to claim 1, A crane characterized in that the lifting element is a hydraulic lifting element, particularly a hydraulic cylinder, or an electric lifting element, particularly a linear actuator.
3. In the crane according to claim 1 or 2, A crane characterized in that the retaining stay is extendable, and as a result, the luffing jib is able to pivot relative to the main boom so that the luffing jib contacts the main boom.
4. In the crane according to any one of claims 1 to 3, The crane is characterized in that one end of the retaining stay is attached to the lower or upper portion of the main boom at a vertical position of the main boom, and the lift element is positioned at that end of the retaining stay.
5. In the crane according to any one of claims 1 to 4, The crane is characterized in that the retaining stay is equipped with a locking means configured to lock the lift element, particularly in the retracted position of the lift element, and is configured in particular to prevent the lift element from extending.
6. In the crane according to claim 5, The crane is characterized in that the locking means includes or is composed of hydraulic elements, particularly hydraulic cylinders, or electric elements, particularly linear actuators, or is composed of electric elements.
7. In the crane according to any one of claims 1 to 6, The crane is characterized in that the lift element has a housing and a piston rod that is extendable from the housing and retractable within the housing.
8. In the crane according to claims 5 and 7, or claims 6 and 7, A crane characterized in that one or more lock lugs, each having an opening, are arranged in the housing, the piston rod has an opening and is provided with a locking element, in particular a locking bolt, the locking element being able to pass through the opening of one or more lock lugs and the opening of the piston rod when the openings are aligned, so as to lock the lift element in a stowed position, and the locking means includes the one or more lock lugs and the locking element.
9. In the crane according to any one of claims 5 to 8, A crane characterized in that the locking means includes a monitoring means, particularly an electromechanical switch or a proximity switch, which allows the position of the locking means, particularly the locking element, to be detected.
10. A crane, and more particularly a method for operating a crane according to any one of claims 1 to 9, The steps include shortening the lift element thereby shortening the retaining stay, and swinging the luffing jib outward relative to the main boom by an initial opening angle, The steps include locking the lift element, A method that includes this.
11. In the method according to claim 10, A method characterized by first raising the main boom and the luffing jib in contact with it from a horizontal position to a vertical position.
12. In the method according to claim 10 or 11, A method characterized by first bringing the crane to a state in which the main boom is in a vertical position and the luffing jib is rotated by an initial opening angle relative to the main boom, and then extending the retaining stay by releasing the lock on one or more of the lift elements and / or extending one or more of the lift elements, thereby rotating the luffing jib inward by an initial opening angle relative to the main boom so that the luffing jib abuts against the main boom, and bringing the crane to a parked position.
13. In the method according to claim 12, The method is characterized by subsequently lowering the main boom and the luffing jib in contact with it from a vertical position to a horizontal position.
14. A method for retrofitting a crane having a main boom and a luffing jib rotatably connected to the main boom, wherein a retaining stay extends between the main boom and the luffing jib, A method characterized by incorporating one or more length-adjustable lift elements into the retaining stay so that the crane becomes the crane described in any one of claims 1 to 9.