Mobile crane with a superstructure having at least one support point for pin connection to the boom

Abstract

To find a compromise between axial play of a boom and ease of handling during the boom installation or disassembly.SOLUTION: There is provided a mobile crane equipped with a superstructure having at least one bearing point for pin-coupling to a boom. The bearing point has two separate sidewalls, each with a hole for receiving the pin. The boom has a hole and is equipped with at least one connection that can be introduced between the sidewalls so that a common connecting pin can be pushed through the hole in the sidewall and the hole in the bearing point. The effective width between the sidewalls is greater than the width of the boom connection. A stepped pin is provided as a connection pin. A shoulder part formed on the stepped pin forms a receiving part for the pin-coupled boom connection in the pin-coupled position.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a mobile crane comprising a superstructure having at least one support point for pin connection to a boom.

Background Art

[0002] In principle, a mobile crane comprises a lower traveling body as a chassis. The superstructure can be pivotally arranged on the lower traveling body via a swivel connection centered on a vertical axis. The crane boom is connected to the superstructure so as to be able to rise and fall. A decisive criterion in the design of a mobile crane is the total weight because the legally regulated maximum axle load for driving operations in road transport must be complied with. Therefore, the possibility of disassembling the boom can frequently occur in large mobile cranes.

[0003] However, such a boom disassembling ability involves a considerable increase in effort and is therefore only provided upon customer request. Therefore, a pin pulling device has to be attached to the crane, for example, to enable pushing or pulling a pin for fixing the boom to the superstructure for installation or disassembly. A typical hydraulic drive of the pin pulling device requires laying of any necessary hydraulic and control lines. The pin connection of the retraction cylinder to the boom also has to be modified accordingly.

[0004] The pin connection between the superstructure and the boom comprises two spaced side walls of the superstructure, between which a connection part of the boom can be introduced. Thereafter, a connection pin is pushed through aligned holes in the side walls and the connection part. The distance between the side walls, i.e., the effective width of the side walls, is adjusted to the width of the connection part in order to limit, as much as possible in the axial direction of the pin, the axial play of the connection part, i.e., the relative movement between the connection part and the side walls. However, there is a drawback that as the play decreases, the installation or removal of the boom becomes more difficult.

[0005] For example, an auxiliary crane lifts the boom during its dismantling. Then, a pin tensioning device pulls out the two boom pins, releasing them from the luffing cylinder. This frees the boom, which the auxiliary crane can then lift and place onto a transport vehicle. However, with regard to the installation or dismantling of the boom using only an auxiliary crane, small gaps between the superstructure's steel frame and the boom, due to tolerances in the chain suspension, suspension projections, and fixing points on the connecting components, can result in the boom rotating around its longitudinal axis. Such rotational movement can cause the boom to jam within the sidewalls of the superstructure's support points, potentially creating a difficult situation to overcome in all installation procedures. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Therefore, a compromise must be found between axial play and ease of handling during boom installation or disassembly. However, a configuration with as little play as possible is desirable, while avoiding relative motion between the boom and the superstructure and providing sufficient play for the installation procedure to simplify work there. [Means for solving the problem]

[0007] This objective is achieved by a mobile crane having the features of claim 1. Advantageous embodiments of the crane are the subject of the dependent claims.

[0008] According to the present invention, it is proposed that the effective width between the side walls of the support points of the superstructure be greater than the width of the boom connector into which it is inserted. This is a requirement for axial play between the side walls and the inserted connector. For example, an axial play of 5 mm between each side of the connector and the side wall on the opposite side is ideal. In this case, the effective width between the side walls is 10 mm greater than the width of the connector. For smooth and rapid installation and removal procedures, an axial play of at least 5 mm per side is sufficient. The present invention is not limited to the exact dimensions of the play exemplified. The key idea of ​​the present invention is to compensate for axial play provided for structural reasons resulting from the design specifications described above, by means of the present invention in crane operations. However, the application of the means of the present invention is independent of the actual play.

[0009] To compensate for structurally induced axial play in the installed state of an operational crane, it is proposed, according to the present invention, to use a stepped pin as a connecting pin. Such a stepped pin is characterized by a stepped change in diameter, thereby forming a step, which is hereafter also called a shoulder. The formed shoulder acts as an axial support (abutment) of the connecting part when the stepped pin is pressed in, limiting the axial play between the side wall and the connecting part.

[0010] In this respect, the shoulder portion protrudes at least partially into the space between the side walls, i.e., the remaining free space between the connector and the side wall positioned opposite it. The inner diameter of the connector is smaller than the diameter of the shoulder portion. In this way, the extracted connector pin provides sufficient play between the connector and the side wall for smooth installation or disassembly. After the connector pin is pushed in, this play is bounded by the shoulder portion, and as a result, relative movement between the connector and the side wall in the axial direction of the connector pin may be eliminated or significantly reduced.

[0011] The pins are typically pressed in the direction in which the boom luffing axis extends to connect the boom to the superstructure. At least two pin connections are preferably pressed separately for boom installation, and at least two of the pins are ideally both designed as stepped pins. These stepped pins are pressable in the direction toward the luffing axis, and the shoulder of each pin connection in this case is preferably located between the outwardly positioned side wall and the connection.

[0012] The boom connection section is provided with a hole for receiving a stepped pin. The bush is preferably inserted into the hole with a precise fit. The effective diameter of the shoulder of the stepped bolt is larger than the diameter of the bush, so that the outward-facing front of the bush abuts against the shoulder positioned opposite the push-in stepped pin, thereby preventing the boom from moving axially toward the superstructure.

[0013] Typically, at least one pin tensioning device, designed as a hydraulic system, is provided for the automatic operation of one or more stepped pins. In this connection, the stepped pin is designed as hollow and therefore acts as the cylinder for the hydraulic drive of the pin tensioning device. The required setting piston is fixed in a static manner to the superstructure and protrudes into the hollow space of the stepped pin. By applying pressure to the hollow space of the stepped pin, the stepped pin can be actuated and moved linearly on the static setting pin. The release pin-side end, with an integrated rod guideway, provides pressure-resistant closure of the hollow stepped pin.

[0014] However, since the inner diameter of the side wall is related to the inner diameter of at least the outerly positioned side wall and the diameter of the shoulder, and the diameter of the pin changes along the possible displacement path of the pin being pushed and pulled by the step, additional guidance for the stepped pin must be provided along the entire displacement path to support its own weight. A possible approach is to provide one or more guide rods positioned parallel to the stepped pin. The guide rods can be fixed to the superstructure, in particular to the side walls, so that the force introduced to the guide rods by the pin can be introduced directly along the path to the superstructure. The stepped pin has corresponding sliding surfaces that slide along the guide rods on the pin action.

[0015] It is conceivable to provide a total of four or more guide rods symmetrically arranged around the stepped pin. The guide rods can be connected at their ends, i.e., at their free ends, by connecting plates. The free ends of the rods of the installation piston can also be engaged with these connecting plates.

[0016] The configuration of the connecting pin according to the present invention, having at least one shoulder as a receiving surface, results in the need for the stepped pin to additionally take over axially acting forces where applicable. Such axial forces result from the rotational motion of the superstructure, particularly the acceleration or deceleration of the superstructure. The stepped pin transfers axially acting forces to the pin tensioning device, but since the pin tensioning device is not designed for such forces under certain circumstances, it must be made larger or an additional force limiting device must be provided. The additional force limiting device can be provided by one or more additional locking means that prevent the linear motion of the pin during crane operation. Such locking means are directly connected to the structure of the superstructure to ensure direct force transmission. According to one embodiment, the additional locking means can be configured as a locking pin extending transversely with respect to the axial axis of the pin. The locking pin can be fixed to the structure of the superstructure via one or more load baffles. Simultaneously, the locking pin is indirectly or directly secured to the stepped pin by the corresponding mating connection means, thereby fixing the stepped pin and allowing the acting axial force to be introduced to the superstructure via the locking pin. The connection of the locking pin to the load baffle and / or mating connection means is designed to be releasable so that the locking connection can be released and the stepped pin can be withdrawn.

[0017] Such locking pins can be directly attached to the end surface structure by appropriate load baffles, particularly while forming a molded fit, thereby enabling direct extraction of axial forces generated in the superstructure. The mating connection element can be a release plate fixed to a stepped pin. In this case, a connection can also be made between the release plate and the locking pin.

[0018] Further advantages and characteristics of the present invention are described in more detail below with reference to embodiments shown in the drawings. [Brief explanation of the drawing]

[0019] [Figure 1]This is a perspective cross-sectional view of the pin connection according to the present invention between a boom and a superstructure into which a stepped pin is inserted. [Figure 2] This is a cross-sectional view from a different direction of the pin connection according to the present invention between the boom and the superstructure into which the stepped pin is inserted. [Figure 3] This is a cross-sectional view from a different direction of the pin connection according to the present invention between the boom and the superstructure into which the stepped pin is inserted. [Figure 4] This is a side view of the pin tensioning device. [Figure 5] This is a side view of a mobile crane in which the boom is connected to the superstructure via a pin joint according to the present invention. [Modes for carrying out the invention]

[0020] The installation and dismantling of the boom in the superstructure of a mobile crane is simplified by the solution according to the present invention. Figure 5 shows a detailed part of such a mobile crane having a lower traveling body 2 having a chassis, and a superstructure 3 is positioned on the lower traveling body 2 so as to be rotatable about a vertical axis. The main boom 4 is connected to the superstructure so as to be luffable about a horizontal axis and is in particular pin-coupled. This pin coupling requires two pin coupling points 5, each having a connecting pin 50 according to the present invention that is pushed from the outside in the direction of the luffing axis of the boom 4.

[0021] Details of the pin connection point 5 according to the present invention will be described below with reference to the detailed diagrams shown in Figures 1 to 4. The pin connection point 5 between the boom 4 and the superstructure 3 is substantially formed by two parallel side walls 31a, 31b of the superstructure 3, spaced apart by an effective width to provide space for introducing the connection portion 4a of the boom 4. The two side walls 31a, 31b of the boom 4 and the connection portion 4a are provided with a hole 4b for receiving the connection pin 50. A boom bush 7 is additionally introduced into the hole 4b of the connection portion 4a.

[0022] To simplify the installation and removal of the boom 4, the width of the boom 4 defined through the interval outside the end face of the boom bush 7 is smaller than the effective width of the steel structure in the upper structure 3, that is, it is maintained between the left and right side walls 31b. The axial play of the connection part 4a achieved on both the left and right sides and each side wall 31b should be within a range of 5 mm respectively. This would be sufficient to substantially speed up the installation and disassembly of the boom 4.

[0023] The connection pin 50 used is designed as a stepped pin 50 having a shoulder 51 with a larger diameter as a substantial feature. The shoulder 51 projects slightly into the empty space between the side walls 31a and 31b from the hole 31c of the right side wall 31b in the attached state (see Fig. 2). Also, the shoulder 51 projects outward on the side located on the opposite side of the side wall 31b in the pin-pressed state. The portion of the shoulder 51 projecting into the effective width between the side walls 31a and 31b forms a receiving part for the front face of the boom bush 7 so that the axial play of the boom 4 is finally limited within the two side walls 31a and 31b. The geometric design of the shoulder 51 is important here. It is necessary to select a sufficient size so that it can inherit the axial force from the front face of the boom bush 7. Here, surface pressure that is transmitted in a harmless way must be generated.

[0024] It is either mirror-inverted or has the same design. For both pin connection points according to Fig. 5, at the time of disassembly, the shoulder 51 separates from the boom bush 7 together with the stepped pin 50, and the available play increases. The boom 4 can be easily removed by an auxiliary crane. In this case, since there is axial play, the installation can be done just as easily.

[0025] In determining the dimensions of the stepped pin 50 and the support points within the side walls 31a, 31b, statistical notches in the pin 50 that exist due to diameter variations must be taken into consideration. The boom bush 7 introduces a force perpendicular (radial to the support points) to the support area (side walls 31a, 31b) of the stepped pin 50. One of the two receiving parts for the stepped pin 50, in this case the outer side wall 31b, has a larger hole diameter for the pin guide path, since the shoulder 51 of the stepped pin 50 must be supported in this area. Thus, the change in cross-section is located in the high-load area of ​​the stepped pin 50. Not only must the stepped pin 50 be able to withstand this load for a long period of time without being damaged, but this load-bearing capacity must also be demonstrated by calculations accompanied by necessary safety measures.

[0026] Axial forces, i.e., axial forces on the pin 50, can occur in addition to radial forces during crane operation. These forces are mainly generated by starting or braking during slewing gear operation. The load here should be accelerated transversely, thereby generating a transverse force at the pin connection point 5 of the boom 4. This axial force must be mainly received by the shoulder portion 51 in the solution according to the present invention, and the stepped pin 50 will transmit the force to the pin tensioning device 10 located on the outside of the superstructure 3.

[0027] The pin tensioning device 10 is hydraulically operable, along with a hollow stepped pin 50 that forms a cylinder hydraulic chamber 50a. An installation piston 57 is positioned within the hydraulic chamber 50a, which is closed in a pressure-sealed manner by an end plate 58. The rod of the installation piston 57 is guided to the outside through a rod guide path in the end plate 58.

[0028] However, the design of the internal hydraulic components of the pin tensioning device 10 cannot be made strong enough to withstand the axial force borne by the shoulder 51 during crane operation. For this reason, the pin tensioning device 10 must be protected from the axial force during crane operation. This is achieved by the latching device 101 (Figures 1 and 4). This includes two load baffles 311, 312 fixed to the superstructure 3 above and below the displacement path of the stepped pin 50. Each of these load baffles 311, 312 provides two guide passages into which the latch pins 313, 314 can be pushed, and in practice, they can be made to extend parallel to each other perpendicularly. Similarly, release plates 52, 53 having guide passages for receiving the latch pins 313, 314 are provided in the connecting plate 58 or directly in the stepped pin 50 as mating connecting elements. When the latch pins 313 and 314 are pushed through the guide paths into the load baffles 311 and 312 or the release plates 52 and 53, the stepped pin 50 is fixed, for example, as shown in Figure 4. In this way, the axial force acting on the stepped pin 50 is directly introduced into the superstructure 3 via the latch pins 313 and 314, thereby effectively protecting the load baffles 311 and 312 and the pin tensioning device 10.

[0029] The upper ends of the latch pins 313 and 314, which protrude above the upper load baffle 311, have eyelets into which the retaining pin 315 can be pushed. When not in use, i.e., when the stepped pin 50 is pulled, the retaining pin 315 is removed and the latch pins 313 and 314 are pulled upward from the plates 311, 312, 52, and 53. The latch pins 313 and 314 can be housed in the superstructure 3 by the holder 316.

[0030] Due to the stepped shape of the stepped pin 50, its diameter changes incrementally in the direction of displacement. The inner diameter of the outer side wall 31b of the superstructure 3 is adjusted to the diameter of the shoulder portion 51. When the stepped pin 50 is pulled by the pin tensioning device 10, the reduced diameter portion of the stepped pin 50 is located within the hole 31c of the side wall 31b, and sufficient support is no longer ensured (see Figure 3). The force and torque caused by its own weight must be absorbed at this position by additional guiding means. For this purpose, a total of four guide rods 102-105 are positioned around the hole 31c of the side wall 31b, which extends outward in the direction of pin displacement. The free ends of the guide rods 102-105 are connected to each other via end plates 59. The opposite ends of the guide rods 102-105 are connected to the side wall. The end plate 58 of the stepped pin 50 is guided by sliding surfaces along each of the guide rods 102-105.

[0031] The free end of the rod of the installation piston 57 is additionally mounted on the end plate 59, where connection ports for hydraulic supply of the pin tensioning device are evenly housed.

Claims

1. The superstructure comprises at least one support point for pin coupling to the boom, The aforementioned support point comprises two spaced side walls, each having a hole for receiving a pin. The boom is provided with at least one connecting portion having a hole into which a common connecting pin can be introduced between the side walls so as to be pushed through the hole in the side wall and the hole in the support point, The effective width between the side walls is greater than the width of the boom connection. A stepped pin is provided as the aforementioned connecting pin. The shoulder portion formed on the stepped pin serves as a receiving portion for the boom connection part that is pin-connected at the pin connection position. A mobile crane characterized by the following features.

2. The shoulder portion of the stepped pin protrudes into the space between the side wall and the connecting portion at the pin connection position, limiting the play of the pin-connected boom in the axial direction of the stepped pin. The mobile crane according to feature 1.

3. The stepped pin is pushed or can be pushed in the direction toward the boom luffing axis. A mobile crane according to feature 1 or 2.

4. The outer diameter of the stepped pin in the shoulder portion is larger than the inner diameter of the bush inserted into the hole in the connecting portion. The shoulder portion forms a receiving portion for the front surface of the bush. A mobile crane according to any one of claims 1 to 3, characterized in that

5. A pin tensioning device for automatically pulling and pushing the stepped pin is provided and is located on the outside of one of the side walls. A mobile crane according to any one of claims 1 to 4, characterized in that

6. The pin pulling device includes a hydraulic cylinder as an actuator, in which a cylinder is formed by the hollow space of the stepped pin. The mounting piston is fixed in a stationary state to the upper structure, and the stepped pin is linearly displaceable on the mounting piston. The mobile crane according to claim 5, characterized in that...

7. One or more guide rods are provided, and the stepped pin is guided along the guide rods so as to be linearly displaceable, and the one or more guide rods are installed on the side wall of the superstructure. A mobile crane according to claim 5 or 6, characterized in that it is a mobile crane.

8. One or more latch pins are provided that extend transversely to the axial direction of the stepped pin and restrict the axial movement of the stepped pin in the tensile direction. A mobile crane according to any one of claims 1 to 7, characterized in that

9. The one or more latch pins are directly supported by the superstructure, and the axial force acting on the pressed stepped pin is directly transmitted to the superstructure. The mobile crane according to claim 8, characterized in that

10. The one or more latch pins are fixed to the superstructure via at least one load baffle, while the stepped pins are releasably connected via a release plate. A mobile crane according to claim 8 or 9, characterized in that it is a mobile crane.

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