Mobile bolt traction device

Abstract

The invention relates to a mobile bolt pulling device, in particular a portable bolt pulling device, for pulling in / out a bolt for connecting components of a construction machine, in particular of a crane, wherein the bolt pulling device is embodied in a compact design and has at least one electric drive with a battery and a linear actuator which can be driven by the drive and serves for moving at least one bolt.

Description

Technical Field

[0001] The invention relates to a mobile bolt pulling device, in particular a portable bolt pulling device, for pulling out and / or inserting bolts, which are used for connecting components of construction machinery, in particular components of cranes. Background Art

[0002] When assembling construction machinery, individual components are often bolted together. A prominent example is the lattice components used to assemble boom systems, particularly lattice booms or hammer booms, boom extensions, and fly jibs and their gantries. Numerous lattice components, which can have identical or different geometries and designs, are bolted together using cross-finger connections. To insert the bolts, the connection points of the lattice components must first be aligned.

[0003] Because the lattice components are relatively heavy, an auxiliary crane must be used to receive them and maneuver them into the installation position, where the two holes overlap on an axis. Because precise alignment is extremely difficult, bolts with a long taper on at least one side are used. These bolts can then be inserted into the holes with sufficient pressure and the interdigital connectors oriented relative to each other. The required pressure can be applied with a large hammer. However, this requires the fitter to remain in close proximity to the interdigital connectors, which presents a potential risk due to the stresses existing between the lattice components. In particular, when removing the second or last bolt of a four-point bolt fastening, relative movement between the lattice components (pivoting or translating) can occur. To minimize this risk, careful coordination must be made between the weight of the lattice components, the forces applied by the auxiliary crane, and the appropriate selection of the force introduction point.

[0004] As an alternative to this manual process, hydraulic bolt pulling devices are currently available. To provide the required high bolting energy, hydraulic bolt pulling devices are typically large in size and weight, making their operation and transportation to the construction site more difficult and time-consuming. An example of a conventional bolt pulling device is Figure 1 The solution consists of a carriage 1, on which a drive unit 2 and a hydraulic bolt tensioning cylinder 3 are mounted. The entire carriage 1 has a length of approximately 2.5 meters and a height of 1.6 meters. Typically, the bolt tensioning cylinder itself is longer than 0.5 meters and weighs approximately 20 kilograms.

[0005] To equip the crane 30, the carriage 1 must be moved to the vicinity of the interdigital connection to be connected. The assembler then picks up the bolt tensioning cylinder 3 and moves it to the lattice element. After securing it to the lattice element as required, the assembler returns to the carriage 1 and activates the drive unit 2 in high-voltage operation until the connection is established. The bolt tensioning cylinder 3 is then installed at the next connection point, optionally requiring the carriage 1 to be moved beforehand.

[0006] exist Figure 2 shows a side view of a known crane, whose boom system consists of a plurality of bolted lattice elements 20. Arrows mark the individual bolting locations. Since each bolting location comprises four bolt connections, a total of 76 bolts must be inserted to assemble the crane shown. It is obvious that equipping such a crane using known bolt-pulling devices is extremely time-consuming.

[0007] An improved solution is therefore desired which significantly simplifies the operation of such a bolt tensioning device. Summary of the Invention

[0008] The present invention proposes a mobile bolt-pulling device with a compact design. This is achieved by an electric drive unit with a built-in battery. This drive unit is significantly smaller and lighter than solutions known from the prior art. Furthermore, the device is self-sufficient and can be used at least temporarily without an external energy supply. The electric drive unit drives a linear actuator for moving at least one bolt. The resulting handheld device combines the drive unit and the actuator in a compact unit that can be easily carried and operated by an operator.

[0009] The mobile bolt-pulling device according to the present invention is useful wherever bolts must be inserted or removed with a high level of force. This is particularly true for construction machinery, where individual components are bolted together using bolt connections during the installation of the construction machine. The mobile bolt-pulling device is preferably used for assembling and disassembling boom systems composed of individual lattice components. Similarly, its use for bolting tracked carriers to the base frame of a construction machine is also a useful application.

[0010] According to a preferred embodiment of the present invention, the linear actuator is implemented in the form of a cylinder, in particular a hydraulic cylinder. It is also conceivable to implement it with a pneumatic cylinder. The bolt can be selectively inserted or pulled out by the movement of the rod.

[0011] The energy conversion is carried out by means of an interposed pump, in particular a hydraulic or pneumatic pump, which is driven by an electric drive and generates the pressure level required to supply the cylinder with energy.

[0012] The installed electric motor is preferably designed for only one direction of rotation and, moreover, is operated only at a constant speed. Accordingly, the use of transmission components or frequency converters can be dispensed with. Instead, the direction and / or speed of movement can be controlled hydraulically or pneumatically, preferably via one or more directional valves connected between the pump and the cylinder.

[0013] The actuator in the form of a cylinder installed is ideally implemented as a two-stroke cylinder. Since in the case of a two-stroke cylinder approximately the same hydraulic pressure is required for both directions of movement, it can work approximately equally in both adjustment directions.

[0014] In order for the linear actuator to be able to impart the necessary kinetic energy to the bolt, the bolt tensioning device must be fixed to the machine structure. For this purpose, the bolt tensioning device includes at least one suitable connection point. A suitable connection point for the bolt tensioning device can be a fork with an embedded bolt. The bolt tensioning device can be quickly and easily attached to an open eyelet in the machine structure using the bolt. Suitable stop surfaces, preferably shoulders on the housing of the bolt tensioning device, can also be envisioned. These shoulders can engage in suitable recesses in the machine structure and thus similarly secure the bolt tensioning device in the actuator's pressing or pulling direction. Specifically, the shoulder can be embodied as an annular projection on the circumference of the actuator's cylinder housing.

[0015] The receiving device of the actuator for indirectly or directly receiving the bolt can be implemented in the form of a claw located on the free end of the piston rod. The bolt can be implemented, for example, by means of an inserted rod (e.g., a threaded element) having a receiving head. The claw can engage the head and thereby exert compressive and tensile forces on the bolt.

[0016] For controlling / operating the bolt tensioning device, an operating unit locally arranged on the bolt tensioning device can be provided. Via this operating unit, the bolt tensioning device can be switched on, the operating mode (ie, application of tension or pressure) can be set, and the operating speed of the actuator can be optionally set.

[0017] Since, as mentioned above, the area surrounding the bolt fastening point can pose a risk to the operator during extraction or insertion, the bolt tensioning device is preferably equipped with a remote control option. To this end, the bolt tensioning device can include a suitable communication interface for connecting a mobile remote control. A wired communication connection with an external remote control is possible, but a radio-based interface is preferred. This extension allows the operator to safely secure the bolt tensioning device in the area of ​​the bolt fastening point on the machine structure and then initiate the force application and bolt extraction or insertion process with the remote control at a sufficient distance. The remote control can be a dedicated remote control for the bolt tensioning device, but commercially available communication devices such as smartphones, tablets, laptops, etc. are also conceivable.

[0018] To monitor the forces generated during bolt actuation by an actuator, it is proposed to equip the bolt-tightening device with an integrated safety device. Because there is a specific correlation between the current consumption of the electric motor and the force to be applied by the actuator to actuate the bolt—for example, the force applied by the cylinder is proportional to the current flowing through the electric motor—the compressive or tensile force currently being applied by the actuator can be determined based on power-related parameters of the motor, particularly the motor current. It is useful to compare the determined electrical value with a relevant limit value. If the limit value is exceeded, the bolt-tightening device can generate a user notification. This notification can be displayed to the user acoustically, visually, or haptically.

[0019] The safety device can expediently be equipped with a mechanism that prevents local operation of the bolt-tensioning device via the integrated operating unit if the force to be applied by the actuator, in particular the detected power / current value of the electric motor, exceeds a defined limit value. If the limit value is exceeded, it is assumed that the required application of force represents a higher risk potential. Ideally, the bolt-tensioning device would then only be operable by remote control via the communication interface.

[0020] In order to protect the bolt tensioning device and / or the structural elements to be assembled from excessively high forces, hydraulic / pneumatic protection devices, such as pressure-limiting valves, can also be installed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further advantages and features of the present invention will be described in more detail below based on the embodiments shown in the accompanying drawings.

[0022] Figure 1 A bolt pulling device according to the prior art is shown.

[0023] Figure 2 A side view of an exemplary crane is shown to illustrate the required bolt connection locations.

[0024] Figure 3 A solution according to the invention for a mobile bolt pulling device of compact construction is shown.

[0025] Figure 4 A top view of the screw connection of a grid element with an embedded screw pulling cylinder is shown,

[0026] Figure 5 Two schematic diagrams showing a bolt pulling device according to the present invention containing a bolt,

[0027] Figure 6 Another schematic diagram shows a bolt pulling device according to the invention used on a crane structure. DETAILED DESCRIPTION

[0028] Figure 3 The present invention illustrates a novel solution for a mobile bolt-pulling device. The handheld device 40 shown includes an electric drive with a battery 41. This drives a hydraulic pump 45, which delivers hydraulic oil depending on the direction and speed of rotation of the motor. The electric motor is designed for only one direction of movement and has a constant speed.

[0029] By means of the pressure built up, the hydraulic pump 45 delivers hydraulic oil to a hydraulic cylinder 46 having a piston rod 49, through which the linear movement of the piston rod can insert or pull the bolt. The hydraulic cylinder 46 is designed as a two-stroke cylinder, which works approximately equally in both adjustment directions.

[0030] To change the direction of movement or the adjustment speed of the piston rod 49 of the cylinder 46, the pump 45 is connected to the cylinder 46 via a 4 / 3-way valve. The adjustment direction and, optionally, the adjustment speed can be changed by the valve position. The operator can trigger the valve operation via the integrated operating unit 44 of the handheld device 40. The electric motor can also be activated via the operating unit 44. The user can pick up and hold the handheld device 40 via the handle 42.

[0031] The bolt pulling device 40 works not only by pressing, but also by pulling, i.e. it can not only insert the bolt but also pull it out. In order to optimally transmit the force to the bolt, the device 40 should be fixed in advance in the area of ​​the bolt fixing point on the machine structure. For this purpose, at least one connection point 47, 47', 47" is provided on the handheld device 40. The first connection point is a fork 47' molded on the end of the cylinder for supporting the bolt laterally. Figure 3 By means of this bolt, the handheld device 40 can be hung, for example, on an open eyelet 23 of the machine structure to fix the handheld device 40 relative to the linear movement of the cylinder 46 produced. Figure 4The grid element 20 is shown with screw fastening points 21. Here, a handheld device 40 is used to actuate the screw fastening point 21 at the bottom left.

[0032] The piston rod 49 has a claw 47 at its extendable end for receiving a threaded element 211 introduced into the bolt 22 to be moved. This can be done, for example, Figure 5 , wherein the left-hand illustration shows the bolt tensioning device 40 with an extended piston rod 49 and a bolt 22 inserted thereby, while the right-hand illustration shows the retracted piston rod 49 and the pulled-out bolt 22 .

[0033] In addition or instead of the fork 47' for connecting the handheld device 40 to the machine structure, a shoulder 47" can also be provided, which can be located in the illustrated embodiment. Figure 6 The shoulder is formed by a ring attached to the cylinder housing of the cylinder 46 , which, when the handheld device 40 is fixed to the machine structure, rests in the annular groove 24 provided for this purpose and thus enables force transmission.

[0034] The two working chambers of cylinder 46 are connected to pump 45 via hydraulic lines (not shown) or internal hydraulic lines. The hydraulic lines are preferably arranged on cylinder 46 to prevent damage during operation or shutdown. The piston rod 49 of cylinder 46 is not specifically guided and can be rotated manually about its longitudinal axis, as connection point 47 may be oriented in a certain direction and manual alignment is necessary to accommodate screw 22. The knurled surface of the piston rod head facilitates manipulation of piston rod 49 and prevents it from slipping during rotation.

[0035] The operating unit 44 of the handheld device 40 cannot always be used due to potential risks to the user. For this reason, the handheld device 40 includes an integrated safety device with a communication interface, which enables radio-based remote control of the handheld device 40 via an external remote control. The internal communication module of the handheld device 40 is able to receive the remote control's instructions and execute them.

[0036] Provision is made for reliable pairing of the remote control and the handheld device 40 to exclude operating errors. The radio range of the remote control is so great that the fitter can leave the risky area of ​​the screw connection 21.

[0037] A sensor for measuring the current drawn by the electric drive is incorporated into the handheld device 40. Since the electric motor is directly connected to the pump 45, the hydraulic pressure applied by the cylinder 46 is proportional to the current flowing in the motor. If the current exceeds a defined threshold, the safety device triggers an acoustic alarm. This alarm provides the operator with information that the bolt 22 is extremely difficult to move. This creates the risk that the grid element 20 connected to the bolt 22 will move after the bolt is removed. In this case, the assembler must use a remote control and remain outside the danger zone. In particular, for safety reasons, the safety device could block the local operating unit 44 in this situation and only allow operation of the handheld device 40 via the remote control.

[0038] The alarm is triggered solely on the basis of the current flow and also sounds when the handheld device 40 is operated via the remote control. Therefore, the second pressure level (the so-called low pressure level as in the previous solutions) is superfluous.

[0039] The piston rod 49 of the cylinder 46 moves until the operator's input is complete. Furthermore, as is common with hydraulic controls, at least one pressure-limiting valve is provided. This ensures that the movement ends even if a limit pressure defined by the valve is exceeded, protecting the components of the interdigital connector 22 from excessive, potentially damaging forces. In most cases, the maximum stroke of the piston rod 49 typically matches the intended path of the bolt 22.

Claims

1. A mobile bolt pulling device for pulling out / inserting bolts used to connect components of construction machinery, wherein: The bolt pulling device comprises at least one electric drive with a battery and a linear actuator drivable by the drive, the linear actuator being used to move at least one bolt. There are means for detecting power-related parameters of the electric motor and an integrated safety device, which monitors whether the determined power-related parameters or current values ​​exceed one or more threshold values, and Therein, the safety device is designed such that if the power-related parameter or the current value exceeds a defined threshold value, it prevents operation of the bolt-pulling device via a local operating unit and only allows remote control.

2. The mobile bolt pulling device according to claim 1, characterized in that: The mobile bolt pulling device is a portable bolt pulling device.

3. The mobile bolt pulling device according to claim 1, characterized in that: The bolts are used to connect components of a crane.

4. The mobile bolt pulling device according to any one of claims 1 to 3, characterized in that: The electromechanical actuator comprises at least one hydraulic or pneumatic cylinder, which is supplied with hydraulic / pneumatic energy by at least one pump driven by the electric drive.

5. The mobile bolt pulling device according to any one of claims 1 to 3, characterized in that: Electric motors can only be operated in one direction of rotation and at a constant rotational speed.

6. The mobile bolt pulling device according to any one of claims 1 to 3, characterized in that: The direction of movement and / or the speed of movement of at least one of the linear actuators can be controlled by a valve or a valve assembly.

7. The mobile bolt pulling device according to claim 6, characterized in that: The linear actuator is a cylinder.

8. The mobile bolt pulling device according to claim 4, characterized in that: The at least one cylinder is designed as a two-stroke cylinder.

9. The mobile bolt pulling device according to any one of claims 1 to 3, characterized in that: The bolt-tensioning device has at least one connection point for fastening to a machine structure, and the actuator has a receiving means for receiving the bolt.

10. The mobile bolt pulling device according to claim 9, characterized in that: The connection point is a fork with a bolt for hooking the bolt pulling device on an open eye of the machine structure and / or a shoulder for engaging in a groove of the machine structure.

11. The mobile bolt pulling device according to claim 9, characterized in that: The receiving means is a claw which serves to receive a receiving rod introduced into the screw.

12. The mobile bolt pulling device according to claim 11, characterized in that: The receiving rod is a threaded member.

13. The mobile bolt pulling device according to any one of claims 1 to 3, characterized in that: The bolt pulling device is provided with a local operating unit and / or a communication module for communicating with an external remote controller.

14. The mobile bolt pulling device according to any one of claims 1 to 3, characterized in that: The device for detecting a power-related parameter of the electric motor is a device in the form of a current sensor.

15. The mobile bolt pulling device according to claim 14, characterized in that: The safety device generates and emits an alarm signal if a threshold value is exceeded.

16. The mobile bolt pulling device according to any one of claims 1 to 3, characterized in that: At least one pressure-limiting valve is provided.

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