JP2022190552A - crane - Google Patents

Abstract

To provide a crane capable of reducing a support reaction force received by a backstop by enlarging a moment arm when a backstop spring pushes back a boom.SOLUTION: A tower crane 10 has an upper rotating bed 12, a boom 14, a gantry 40 and a backstop 1. The backstop 1 includes a backstop base end part 1A, a backstop tip 1B, and a spring 4. The backstop base end part 1A is supported by one of the structures of a gantry top 40T and the tip of a lower boom 14A, and the backstop tip 1B is in contact with the other structure of the gantry top 40T and the tip of the lower boom 14A.SELECTED DRAWING: Figure 6

Description

The present invention relates to cranes.

Patent document 1 has a crane body, a boom supported by the crane body so as to be rotatable in the hoisting direction, and a backstop for preventing the boom from falling backward with respect to the crane body. A crane is disclosed.

The backstop is supported by the lower boom forming the base end of the boom. The backstop has an outer cylinder, an inner cylinder, and a spring. The inner cylinder is inserted into the outer cylinder and moves relative to the outer cylinder, thereby expanding and contracting the backstop. The spring is arranged so as to be interposed between the outer cylinder and the inner cylinder. The spring allows the backstop to expand and contract between a free length and a compressed length. When the boom is erected with respect to the crane body, the backstop supports the boom from behind while the spring is compressed by the tip of the backstop coming into contact with a support portion provided on the crane body. Further, when the crane is disassembled, the boom is pushed back forward by the urging force of the spring and falls down.

JP 2018-131330 A

In the technique described in Patent Document 1, since the distance between the support portion of the backstop on the crane body side and the base end portion of the boom is short, the angle formed by the lower boom and the backstop becomes a relatively small acute angle, resulting in the backstop breaking. The moment arm when the spring pushes back the boom also tends to be small. For this reason, a large spring force is required, and as a result, the strength required for the backstop is increased, resulting in the problem of an increase in the size and weight of the backstop.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a crane capable of reducing the support reaction force received by the backstop by enlarging the moment arm when the backstop spring pushes back the boom. With the goal.

The present invention provides a crane body, a base end of a hoisting body rotatably supported by the crane body, a tip end of the hoisting body on the side opposite to the base end of the hoisting body, and the base of the hoisting body. a hoisting body hoistable relative to the crane body including a hoisting body support portion set between an end portion and the tip of the hoisting body; A gantry that is erected, and a backstop capable of supporting the undulating body from behind in a state in which the undulating body is erected with respect to the crane body. The backstop includes: a backstop base end portion supported by one of the gantry upper end portion and the undulating body support portion; a backstop tip that abuts the other of the gantry upper end and the undulator support that is different from the one structure.

According to this configuration, since the backstop is arranged so as to connect the gantry upper end of the gantry and the undulating body support portion of the lower undulating body, the angle between the center line of the undulating body and the backstop is a large acute angle. is set to Therefore, it is possible to increase the moment arm when the backstop pushes back the undulating body, and it is possible to reduce the support reaction force that the backstop receives from the undulating body. As a result, the need to increase the size and weight of the backstop to resist the support reaction force is reduced.

In the above configuration, the backstop is extendable and interposed between the backstop proximal end and the backstop distal end such that the distance between the backstop proximal end and the backstop distal end varies. It is desirable to further include a spring.

According to this configuration, it is possible to increase the moment arm when the spring of the backstop pushes back the undulating body, and it is possible to reduce the support reaction force that the backstop receives from the undulating body. As a result, an increase in the size of the spring is suppressed, and the need to increase the size and weight of the backstop in order to resist the support reaction force of the spring is reduced.

In the above configuration, the gantry has a front leg base end portion supported by the crane main body behind the derricking body base end portion, and a front leg tip portion disposed on the opposite side to the front leg base end portion. a pair of left and right front legs respectively extending obliquely rearward from the front leg base end; a rear leg base end supported by the crane body behind the front leg base end; and the rear leg base end A pair of left and right rear leg portions extending upward from the rear leg base end portion, each including a rear leg tip portion disposed on the opposite side, and the front leg tip portion and the rear leg tip portion on both sides in the left and right direction. and a connecting shaft connecting the pair of left and right connecting portions to each other in the left-right direction, wherein the connecting shaft constitutes the upper end of the gantry and the tip of the backstop Alternatively, it is desirable to support the base end of the backstop.

According to this configuration, the reaction force that the backstop receives from the undulating body can be received by the gantry upper end portion of the gantry having a strong structure. In addition, since the connecting shaft of the gantry also has the function of supporting the backstop, the need to newly provide a dedicated structure for supporting the backstop at the upper end of the gantry is reduced.

In the above configuration, a backstop intermediate portion of the backstop set between the backstop base end portion and the backstop tip portion, and a backstop intermediate portion set between the front leg base end portion and the front leg tip portion. a support member for supporting the backstop by connecting the front leg middle portion and the front leg intermediate portion thereof to each other, wherein the tip portion of the backstop moves toward the other structure as the hoisting body stands up with respect to the crane body. It is desirable to further include a support member that maintains the relative orientation of the backstop with respect to the gantry so that it can abut against the gantry.

According to this configuration, the structure of the support member can be simplified and the length of the support member can be shortened, compared to the case where the structure for supporting the backstop is provided in the crane body. It is possible to suppress the bending of the support member that supports the .

In the above configuration, the support member is attached to and detached from at least one of the front legs and the backstop so as to allow the backstop to change posture between a supporting posture and a retracted posture. The support posture is a posture in which the backstop can support the flexing body from behind, and the retracted posture is arranged so that the backstop overlaps the front legs more than the support posture. It is desirable to be in a position where

According to this configuration, when the backstop does not support the undulating body, the support member can be removed from the backstop or the front leg, so that the backstop can be placed in a retracted posture along the front leg. , the space required for transporting or storing the crane can be reduced.

In the above configuration, at least one end of the backstop distal end portion and the backstop proximal end portion has a pair of engaging pieces spaced apart in the vertical direction. It is desirable that, of the portion and the other structural portion, the structural portion that supports the at least one end portion has a shaft portion that fits into a recess formed between the pair of engaging pieces.

According to this configuration, the shaft portion can rotatably support the backstop base end portion of the backstop without attaching a dedicated mounting member for the backstop to the upper end portion of the gantry. Therefore, the structure of the portion that supports the backstop can be simplified, and the work of attaching the backstop to the upper end of the gantry is facilitated.

In the above configuration, engagement holes are formed in the tip portions of the pair of engagement pieces along a direction orthogonal to the left-right direction, and the pair of engagement pieces are engaged with the shaft portions in a state where the shaft portions are fitted in the recesses. It is desirable to further include a retaining pin that prevents the shaft portion from detaching from the recessed portion by being inserted into the engaging hole.

According to this configuration, it is possible to reliably prevent the shaft from detaching from the recess between the pair of engaging pieces.

According to the present invention, it is possible to provide a crane capable of increasing the moment arm when the backstop spring pushes back the boom and reducing the support reaction force received by the backstop.

1 is a side view of a crane according to a first embodiment of the invention; FIG. 4 is an enlarged side view of the lower jib and gantry of the crane according to the first embodiment of the present invention; FIG. FIG. 4 is an enlarged side view of the upper end of the gantry of the crane according to the first embodiment of the present invention; FIG. 4 is an enlarged plan view of the upper end of the gantry of the crane according to the first embodiment of the present invention; FIG. 4 is an enlarged side view of the periphery of the tip of the backstop of the crane according to the first embodiment of the present invention; FIG. 4 is an enlarged plan view of the periphery of the tip of the backstop of the crane according to the first embodiment of the present invention; Figure 3 is a view of the support member of Figure 2 along arrow VII; FIG. 5 is an enlarged side view of the upper end of the gantry of the crane according to the first modified embodiment of the present invention; FIG. 8 is an enlarged side view of the lower jib and gantry of the crane according to the second embodiment of the present invention; FIG. 8 is an enlarged side view of the upper end of the gantry of the crane according to the second embodiment of the present invention; FIG. 8 is an enlarged plan view of the upper end of the gantry of the crane according to the second embodiment of the present invention; FIG. 7 is an enlarged side view of the vicinity of the base end portion of the backstop of the crane according to the second embodiment of the present invention; FIG. 8 is an enlarged plan view of the vicinity of the base end portion of the backstop of the crane according to the second embodiment of the present invention; FIG. 8 is an enlarged side view of the upper end of the gantry of the crane according to the second modified embodiment of the present invention;

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a tower crane 10 (crane) according to one embodiment of the present invention. FIG. 2 is an enlarged side view of the periphery of lower boom 14A and gantry 40 of tower crane 10. As shown in FIG. FIG. 3 is an enlarged side view of the upper end of the gantry 40 of the tower crane 10. FIG. FIG. 4 is an enlarged plan view of the upper end of the gantry 40 of the tower crane 10. FIG. FIG. 5 is an enlarged side view of the periphery of the tip of the backstop 1 of the tower crane 10. FIG. FIG. 6 is an enlarged plan view of the periphery of the tip of the backstop 1 of the tower crane 10. As shown in FIG. FIG. 7 is a view of support member 24 of FIG. 2 as viewed along arrow VII.

It should be noted that, hereinafter, directions of “up”, “down”, “left”, “right”, “front” and “back” are shown in each figure, but the directions are related to each embodiment. It is shown for convenience in order to explain the structure and assembly method of the crane 10, and does not limit the moving direction of the crane, the mode of use of the backstop, etc. according to the present invention.

The tower crane 10 includes a crawler lower traveling body 11 , an upper revolving body 12 (crane body), an operator's cab 13 , a boom 14 , a jib 15 , a boom hoisting winch 16 , and a hoisting rope 17 .

The lower running body 11 can run on a running surface such as the ground. In addition, the undercarriage 11 may have a moving structure other than the crawler, for example, using a wheel. Moreover, the crane according to the present invention may be a fixed crane that does not have a moving structure, a luffing crane other than a tower crane, or a crane that does not have a jib.

The upper revolving body 12 is supported by the lower traveling body 11 so as to be able to revolve around a revolving central axis extending in the vertical direction. The operator's cab 13 is provided in the front part of the upper revolving body 12, and an operator of the tower crane 10 can board it.

The boom 14 is supported by a support shaft 12A (FIG. 2) provided at the front end of the upper swing body 12 so as to be rotatable in the up-and-down direction. Specifically, the boom 14 has a boom base end portion 14P (the base end portion of the hoisting body) and a boom tip portion 14Q (the tip portion of the hoisting body). The boom base end portion 14P is a base end portion of the boom 14, and is rotatably supported by the support shaft 12A around a rotation center axis extending in the left-right direction. The boom tip 14Q is the tip of the boom 14 opposite to the boom base 14P. Moreover, in this embodiment, the boom 14 is configured by connecting a plurality of boom members to each other along the longitudinal direction thereof. In particular, boom 14 has a lower boom 14A including a boom base 14P. The lower boom 14A has a structure that expands from the boom base end 14P toward the tip side, and is configured by connecting a plurality of pipe members.

Furthermore, the boom 14 has a pair of left and right support frames 14B (boom support portions 14R (elastic body support portions)) (Figs. 2, 5 and 6). The support frame 14B is a portion of the boom 14 that is set between the boom base end 14P and the boom tip end 14Q. More specifically, the support frame 14B is arranged on the tip side portion of the rear surface of the lower boom 14A. As shown in FIG. 6, a pair of left and right support frames 14B are fixed to a pipe material extending in the left-right direction that constitutes a part of the lower boom 14A and are spaced apart in the left-right direction. As shown in FIG. 5, in this embodiment, the pair of left and right support frames 14B has a V shape when viewed from the side. In other words, each support frame 14B consists of a pair of engaging pieces spaced apart in the vertical direction. Between the pair of engaging pieces is formed a concave portion into which the tip engaging portion 31 of the backstop 1 described later is fitted (FIG. 5).

The jib 15 is supported by a boom tip portion 14Q of the boom 14 so as to be able to rise and fall.

A boom hoisting winch 16 is mounted on the rear portion of the upper rotating body 12 . The boom hoisting winch 16 has the function of reeling in and unreeling the hoisting rope 17 to hoist the boom 14 .

Further, the tower crane 10 includes a lower spreader 18A, an upper spreader 18B, a pair of left and right pendant ropes 19 (boom guy lines), and a gantry 40.

A gantry 40 is erected on the upper rotating body 12 behind the boom 14 . The gantry 40 functions as a support for the boom 14 hoisting motion. At this time, the gantry upper end 40T (FIG. 2) of the gantry 40 supports the boom 14. As shown in FIG. The gantry 40 has a pair of left and right front legs 41, a pair of left and right rear legs 42, a pair of left and right connecting portions 43, and a connecting shaft 44 (FIGS. 3 and 4).

The pair of left and right front legs 41 are supported by the upper revolving body 12 at intervals in the left-right direction. Each front leg portion 41 includes a front leg base end portion supported by the upper rotating body 12 behind the boom base end portion 14P, and a front leg distal end portion disposed on the opposite side to the front leg base end portion. It extends obliquely rearward and upward from the base end of the front leg.

The pair of left and right rear legs 42 are supported on the upper revolving body 12 behind the pair of left and right front legs 41 at intervals in the left-right direction. Each rear leg 42 has a rear leg base end supported by the upper swing body 12 behind the front leg base end, and a rear leg distal end disposed on the opposite side to the rear leg base end. each including and extending upwardly from said rear leg proximal end.

A pair of left and right connecting portions 43 connect the front leg tip portion and the rear leg tip portion on both sides in the left-right direction. In this embodiment, the connecting portion 43 has a substantially triangular shape, as shown in FIG.

The connecting shaft 44 is arranged at the upper end (top) of the connecting portion 43 . The connecting shaft 44 is a shaft portion that connects the pair of left and right connecting portions 43 to each other in the left-right direction. As a result, the connecting shaft 44 connects the front leg distal ends of the pair of left and right front legs 41 . In this embodiment, the connecting shaft 44 constitutes a part of the gantry upper end portion 40T. Further, the rear leg tip portions of the pair of left and right rear leg portions 42 are connected to the lower portion of the connecting portion 43 by connecting pins 43A. The connecting shaft 44 is rotatably mounted with the guide sheave 17S and the lower spreader 18A.

With the structure as described above, the gantry 40 has the left and right front legs 41 and the left and right rear legs 42 integrated by the support shaft 12B, the support shaft 12C, the connecting pin 43A and the connecting shaft 44, and the boom as a strong structure. 14 can be supported from behind.

The lower spreader 18A is connected to a connecting shaft 44 (gantry upper end 40T) and has a lower sheave block (not shown). A plurality of sheaves are arranged in the width direction (horizontal direction) in the lower sheave block.

The upper spreader 18B is arranged above the lower spreader 18A with a predetermined spacing. The upper spreader 18B is connected to the boom tip 14Q via a pair of left and right pendant ropes 19. As shown in FIG. The upper spreader 18B has an upper sheave block (not shown). A plurality of sheaves are arranged in the width direction (horizontal direction) in the upper sheave block.

The aforementioned hoisting rope 17 is pulled out from the boom hoisting winch 16, hooked on the guide sheave 17S arranged at the gantry upper end 40T, and then connected to the lower sheave block of the lower spreader 18A and the upper sheave block of the upper spreader 18B. is multiplied multiple times between Note that the tip of the hoisting rope 17 after being wound around the lower sheave block and the upper sheave block is fixed to the gantry upper end 40T.

The boom hoisting winch 16 reels in and pays out the hoisting rope 17 to change the distance between the lower sheave block of the lower spreader 18A and the upper sheave block of the upper spreader 18B, and raise the boom 14 to the gantry 40. The boom 14 is raised and lowered while being rotated relatively.

Tower crane 10 further comprises backstop 1 and support member 24 .

The backstop 1 can support the boom 14 from behind when the boom 14 stands up against the upper swing body 12 . The backstop 1 that limits the elevation of the boom 14 in this manner is arranged between the connecting portion 43 at the tip of the gantry 40 and the tip of the lower boom 14A of the boom 14 .

Functionally describing the backstop 1, the backstop 1 has a backstop proximal end portion 1A, a backstop distal end portion 1B, and a backstop intermediate portion 1M.

The backstop proximal end portion 1A is the proximal end portion of the backstop 1, and in this embodiment, rotates about the rotation center axis extending in the left-right direction on the connecting shaft 44 (gantry upper end portion 40T) (one structural portion). supported as possible.

The backstop tip portion 1B is the tip portion of the backstop 1, and in this embodiment, as the boom 14 stands up with respect to the upper swing body 12, the support frame 14B (one structural portion) of the lower boom 14A the other structure).

As shown in FIG. 2, the intermediate backstop portion 1M is set in the backstop 1 between the backstop proximal end portion 1A and the backstop distal end portion 1B.

On the other hand, to structurally describe the backstop 1 , the backstop 1 has an outer cylinder 2 , an inner cylinder 3 and a spring 4 .

The outer cylinder 2 has a cylindrical shape with a centerline extending in the axial direction of the backstop 1 . The outer cylinder 2 has an outer cylinder base end portion 21 (FIG. 3). The outer cylinder base end portion 21 constitutes the backstop base end portion 1A of the backstop 1 (one end, the end on the rotation support side). Further, the distal end portion of the outer cylinder 2 opposite to the outer cylinder base end portion 21 is open and communicates with the inner space of the outer cylinder 2 .

The gantry 40 described above has a backstop fixture 45 arranged across the connecting portion 43 and the connecting shaft 44 . The backstop fixture 45 includes a support shaft 45A. The outer cylinder base end portion 21 of the outer cylinder 2 is rotatably connected to the support shaft 45A (FIGS. 3 and 4). As a result, the connecting shaft 44 supports the backstop base end portion 1A of the backstop 1 via the backstop fixture 45 .

The inner cylinder 3 has a cylindrical shape with a center line extending in the axial direction of the backstop 1 (the same center line as the outer cylinder 2), and has an outer diameter slightly smaller than the inner diameter of the outer cylinder 2. there is The tip of the inner cylinder 3 is slidably inserted into the inner space of the outer cylinder 2, and the backstop 1 expands and contracts as the inner cylinder 3 moves relative to the outer cylinder 2 in the axial direction.

The inner cylinder 3 has a tip engaging portion 31 (FIG. 5). The front end engaging portion 31 is the base end portion of the inner cylinder 3 and constitutes the backstop front end portion 1B (the other end portion) of the backstop 1 . The distal end engaging portion 31 is a disk-shaped member fixed to the distal end portion of the inner cylinder 3 . When the boom 14 stands up with respect to the upper revolving body 12, the contact portion 31A, which is the outer peripheral surface of the tip engaging portion 31, contacts the support frame 14B of the lower boom 14A.

A spring 4 is arranged so as to be interposed between the outer cylinder 2 and the inner cylinder 3 . The spring 4 restricts the upward motion of the boom 14 by exerting its urging force on the boom 14 when the boom 14 stands up with respect to the upper revolving body 12 . Spring 4 includes a large spring 4A and a small spring 4B (Fig. 5). The large spring 4A is mainly fitted on the outer peripheral surface of the outer cylinder 2, and the small spring 4B is mainly fitted on the outer peripheral surface of the inner cylinder 3. The wire diameter of the small spring 4B is set to be smaller than the wire diameter of the large spring 4A, and by starting to contract before the large spring 4A, the spring 4 can receive the boom 14 loosely.

In other words, the spring 4 is interposed between the backstop proximal end portion 1A and the backstop distal end portion 1B so that the distance between the backstop proximal end portion 1A and the backstop distal end portion 1B changes. It is a stretchable spring material.

The support member 24 (FIGS. 2 and 7) is interposed between the backstop 1 and the front leg portion 41 to support the backstop 1. As shown in FIG. Specifically, as the boom 14 stands up with respect to the upper revolving body 12, the backstop tip portion 1B of the support member 24 may come into contact with the support frame 14B (the other structural portion) of the lower boom 14A. Maintain the relative attitude of the backstop 1 to the gantry 40 as much as possible.

The support member 24 is a rod-shaped member including one end and the other end. One end of the support member 24 is rotatably supported (connected) to a support member fixture 46 (intermediate front leg portion) fixed to the front leg portion 41 . The support member fixture 46 is set (arranged) between the front leg base end portion and the front leg tip portion of the front leg portion 41 . On the other hand, the other end of the support member 24 is rotatably supported (connected) to a backstop intermediate portion 1M arranged closer to the proximal end than the central portion of the outer cylinder 2 in the longitudinal direction. The other end of the support member 24 is detachable from the intermediate backstop portion 1M of the outer cylinder 2. As shown in FIG. Also, one end of the support member 24 may be detachable from the support member fixture 46, or the both ends may be detachable.

With reference to FIG. 2, the support member 24 can be changed in posture between a standing posture with respect to the front leg portion 41 and a lying posture with respect to the front leg portion 41 by attaching and detaching as described above. This change in posture of the support member 24 allows the backstop 1 to change posture between the supporting posture and the retracted posture. The support posture is a posture in which the backstop 1 can support the boom 14 from behind, and the retracted posture is a posture in which the backstop 1 is arranged so as to overlap the front leg portion 41 more than the support posture.

As shown in FIGS. 1 and 2, in this embodiment, the backstop 1 is arranged to connect the gantry upper end 40T (tip) of the gantry 40 and the tip of the lower boom 14A. , the angle θ between the center line of the boom 14 and the backstop 1 is set to be a large acute angle. Therefore, it is possible to increase the moment arm L when the boom 14 is pushed back by the spring 4 of the backstop 1, and the support reaction force that the backstop 1 receives from the boom 14 can be reduced. As a result, the increase in size of the spring 4 is suppressed, and the need to increase the size and weight of the backstop 1 in order to resist the support reaction force of the spring 4 is reduced.

Note that, in the present embodiment, the component of the force acting on the boom 14 from the biasing force of the spring 4 in the direction perpendicular to the center line of the boom 14 is greater than the component in the direction parallel to the center line of the boom 14. , the posture and angle of the backstop 1 are set. Therefore, the biasing force of the spring 4 can be efficiently applied to the boom 14 .

Further, in the present embodiment, the gantry 40 has a pair of left and right front legs 41, a pair of left and right rear legs 42, a pair of left and right connecting portions 43, and a connecting shaft 44. The connecting shaft 44 is a backstop. 1 backstop base end portion 1A is rotatably supported.

According to such a configuration, the reaction force that the backstop 1 receives from the boom 14 can be received by the gantry upper end portion 40T of the gantry 40 having a strong structure. In addition, since the connecting shaft 44 also has the function of supporting the backstop 1, the need to newly provide a dedicated structure for supporting the backstop 1 at the gantry upper end portion 40T is reduced.

Further, in this embodiment, the tower crane 10 has a support member 24 interposed between the backstop 1 and the front leg 41 to support the backstop 1 .

According to such a configuration, the structure of the support member 24 can be simplified and the length of the support member 24 can be shortened as compared with the case where the structure for supporting the backstop 1 is provided in the upper revolving body 12. , and the bending of the support member 24 that supports the backstop 1 can be suppressed.

Also, in this embodiment, the support members 24 are provided with respect to at least one of the backstop 1 and the front legs 41 so as to allow the backstop 1 to change posture between the supporting posture and the retracted posture. is detachable.

According to such a configuration, when the backstop 1 does not support the boom 14, the support member 24 is removed from the backstop 1 or the front leg portion 41, thereby disposing the backstop 1 along the front leg portion 41. As a result, the space required for transporting or storing the tower crane 10 can be reduced.

Next, a first modified embodiment of the present invention based on the above first embodiment will be described. FIG. 8 is an enlarged side view of the upper end portion of the gantry 40 of the tower crane 10 (crane) according to this modified embodiment. In addition, in this modified embodiment, differences from the previous first embodiment will be mainly described, and descriptions of common points will be omitted. The same applies to subsequent embodiments.

With reference to FIG. 8, in this modified embodiment, the outer cylinder base end portion 22 of the outer cylinder 2 constituting the backstop base end portion 1A of the backstop 1 has upper and lower bases arranged at intervals in the vertical direction. A bifurcated clevis including a pair of projecting pieces 22A (engaging pieces) is arranged. A mounting hole 22B (engagement hole) is formed at the tip of each protruding piece 22A so as to pass through the protruding piece 22A along a direction perpendicular to the horizontal direction (vertical direction in FIG. 8). As shown in FIG. 8, the connecting shaft 44 (shaft portion) is fitted into the recess formed between the pair of projecting pieces 22A, and the mounting pin 23 (retaining pin) is inserted into the mounting hole 22B of each projecting piece 22A. By inserting, the outer cylinder proximal end portion 22 of the outer cylinder 2, that is, the backstop proximal end portion 1A is rotatably supported by the connecting shaft 44. As shown in FIG. A retaining member (not shown) is further attached to the tip (lower end) of the mounting pin 23 inserted through the pair of mounting holes 22B. As a result, the connecting shaft 44 is more reliably prevented from coming off the recess.

In this modified embodiment, the connecting shaft 44 rotatably supports the backstop base end portion 1A of the backstop 1 without attaching the backstop fixture 45 to the connecting shaft 44 as in the first embodiment. can do. As a result, the structure of the portion that supports the backstop 1 can be simplified, and the work of attaching the backstop 1 to the connecting shaft 44 (gantry upper end portion 40T) is facilitated.

Contrary to this modified embodiment, the tip engaging portion 31 (backstop tip portion 1B) shown in FIG. (See FIG. 6). Moreover, both the backstop proximal end portion 1A and the backstop distal end portion 1B may be provided with a pair of upper and lower protruding pieces 22A.

Next, a second embodiment of the invention will be described. FIG. 9 is an enlarged side view of the periphery of the lower boom 14A and the gantry 40 of the tower crane 10 according to this embodiment. FIG. 10 is an enlarged side view of the upper end of the gantry 40 of the tower crane 10. FIG. FIG. 11 is an enlarged plan view of the upper end of the gantry 40 of the tower crane 10. FIG. 12 is an enlarged side view of the periphery of the base end of the backstop 1 of the tower crane 10. FIG. FIG. 13 is an enlarged plan view of the vicinity of the base end of the backstop 1 of the tower crane 10. FIG. In this embodiment, differences from the first embodiment will be mainly described, and descriptions of common points will be omitted.

In this embodiment, the base end of the outer cylinder 2 of the backstop 1 (the backstop base end 1A) is rotatably supported (connected) to the upper end of the back surface of the lower boom 14A, and the boom 14 stands up. As a result, the base end (backstop tip end portion 1B) of the inner cylinder 3 of the backstop 1 comes into contact with the gantry upper end portion 40T of the gantry 40, so that the gantry 40 and the backstop 1 support the boom 14 from behind. do.

As shown in FIGS. 9 and 12, the backstop base end portion 1A of the backstop 1 is rotatably supported by a backstop fixture 14C (boom support portion 14R) provided at the upper end portion of the lower boom 14A. ing. Further, the backstop tip portion 1B of the backstop 1 abuts on a support member fixture 46 provided on the connecting shaft 44. As shown in FIG.

Specifically, the backstop 1 has an outer cylinder 2, an inner cylinder 3, and a spring 4 also in this embodiment.

An outer cylinder base end portion 21 of the outer cylinder 2 is rotatably supported by a support shaft 14D of a backstop fixture 14C fixed to the tip portion of the lower boom 14A. Further, the distal end of the outer cylinder 2 is open and communicates with the internal space of the outer cylinder 2 .

Further, the tip of the inner cylinder 3 is slidably inserted inside the outer cylinder 2 . As shown in FIGS. 10 and 11, the front end engaging portion 31 (backstop front end portion 1B) of the inner cylinder 3 is provided with a contact portion 31A as in the first embodiment. comes into contact with the support member fixture 46 as it stands up. The support member fixture 46 is arranged across the connecting portion 43 and the connecting shaft 44 . Also in this case, the connecting shaft 44 of the gantry 40 can receive the weight of the boom 14 .

Further, the base end portion of the support member 24 is rotatably supported by the support member fixture 14E fixed to the base end portion of the lower boom 14A from the backstop fixture 14C. On the other hand, the distal end portion of the support member 24 is rotatably connected to the base end side portion (backstop intermediate portion 1M) of the outer cylinder 2 relative to the intermediate portion in the longitudinal direction. A tip portion of the support member 24 is detachable from the intermediate backstop portion 1M.

In this embodiment, when the support member 24 is erected with respect to the lower boom 14A and the tip of the support member 24 is attached to the intermediate backstop portion 1M, the backstop 1 is in a supporting posture capable of supporting the boom 14. FIG. On the other hand, when the tip portion of the support member 24 is separated from the backstop intermediate portion 1M, the support member 24 can rotate along the back surface of the lower boom 14A, and the backstop 1 moves along the backstop base end portion 1A. It rotates as a fulcrum and is stored along the back surface of the lower boom 14A.

Also in this embodiment, since the backstop 1 is arranged between the tip of the lower boom 14A and the gantry upper end 40T of the gantry 40, the angle θ between the center line of the boom 14 and the backstop 1 is large. An acute angle is possible, and the moment arm L when the spring 4 pushes back the boom 14 can be increased. As a result, the support reaction force that the backstop 1 receives is reduced, and the size and weight of the backstop 1 can be reduced.

Next, a second modified embodiment of the present invention based on the above second embodiment will be described. FIG. 14 is an enlarged side view of the upper end portion of the gantry 40 of the tower crane 10 (crane) according to this modified embodiment.

Referring to FIG. 14, in this modified embodiment, a pair of upper and lower protruding pieces 32A (engagement pieces) are provided at the inner cylinder base end portion 32 of the inner cylinder 3 constituting the backstop distal end portion 1B of the backstop 1. A bifurcated clevis containing As shown in FIG. 14, by fitting the connecting shaft 44 into the recess formed between the pair of projecting pieces 32A, the inner cylinder base end portion 32 of the inner cylinder 3, that is, the backstop distal end portion 1B is connected. It is supported on shaft 44 . In this case, the support reaction force that the backstop 1 receives from the boom 14 can be directly received by the connecting shaft 44 . Therefore, by supporting the backstop 1 with the gantry 40 having a strong structure, it is possible to stably prevent the boom 14 from falling backward.

The structure of the first modified embodiment shown in FIG. 8 may be applied to the backstop proximal end portion 1A (FIGS. 12 and 13) in this modified embodiment.

The crane 10 including the backstop 1 according to each embodiment of the present invention has been described above. In addition, this invention is not limited to these forms. In the present invention, the following modified embodiments are possible.

(1) In the above embodiment, the crane 10 shown in FIG. 1 was used, but the present invention is not limited to this, and can be applied to cranes having other structures. For example, a crane that does not have a jib at the tip of the boom may be used.

(2) The support member 24 may be fixed relative to the backstop 1 or the gantry 40 .

(3) In the above embodiment, the backstop 1 has the spring 4, but the present invention is not limited to this. The backstop 1 may have no spring 4 or may support the boom 14 with the outer cylinder 2 and the inner cylinder 3 . Further, the structure of the backstop 1 is not necessarily limited to the structure of the outer cylinder 2 and the inner cylinder 3, as long as it has a backstop proximal end portion 1A and a backstop distal end portion 1B.

1 Backstop 10 Tower Crane 11 Lower Traveling Body 12 Upper Revolving Body 12A, 12B, 12C Support Shaft 13 Driver's Cabin 14 Boom 14A Lower Boom 14B Support Frame 14C Backstop Fixture 14D Support Shaft 14E Support Member Fixture 14P Boom Base End (Base end of undulating body)
14Q boom tip (tip of hoisting body)
14R Boom support (elastic body support)
15 Jib 16 Boom hoisting winch 17 Hoisting rope 17S Guide sheave 18A Lower spreader 18B Upper spreader 19 Pendant rope 1A Backstop base end 1B Backstop tip 1M Backstop intermediate part 2 Outer cylinders 21, 22 Outer cylinder base 22A Projection piece (engagement piece)
22B Mounting hole (engagement hole)
23 Mounting pin (Retaining pin)
24 Support member 3 Inner cylinder 31 Tip engaging part 31A Contact part 32 Inner cylinder base end 32A Protruding piece 4 Spring 40 Gantry 40T Gantry upper end 41 Front leg 42 Rear leg 43 Connecting part 43A Connecting pin 44 Connecting shaft 45 Bucks Top fixture 45A Support shaft 46 Support member fixture (intermediate portion of front leg)
4A Large spring 4B Small spring

Claims (7)

a crane body;
Set between the base end of the hoisting body rotatably supported by the crane body, the tip of the hoisting body on the side opposite to the base end of the hoisting body, the base end of the hoisting body, and the tip of the hoisting body a luffer hoistable relative to the crane body, the hoist including a hoist support;
a gantry that includes a gantry upper end and is erected on the crane body behind the undulating body;
a backstop capable of supporting the hoisting body from behind in a state in which the hoisting body is erected with respect to the crane body;
with
The backstop is
a backstop base end portion supported by one structural portion of the gantry upper end portion and the undulating body support portion;
a backstop tip portion that abuts against the other structural portion of the gantry upper end portion and the undulating body support portion, which is different from the one structural portion, as the undulating body rises with respect to the crane main body; ,
a crane. The backstop further comprises a stretchable spring interposed between the backstop proximal end and the backstop distal end such that the distance between the backstop proximal end and the backstop distal end varies. A crane according to claim 1. The gantry is
A front leg base end portion supported by the crane main body behind the derricking body base end portion, and a front leg tip portion disposed on the side opposite to the front leg base end portion, and obliquely from the front leg base end portion. a pair of left and right front legs respectively extending rearward;
a rear leg base end portion supported by the crane body behind the front leg base end portion; and a rear leg tip portion disposed on the side opposite to the rear leg base end portion, a pair of left and right rear legs extending upward from the part;
a pair of left and right connecting portions that connect the tip portions of the front legs and the tip portions of the rear legs on both sides in the left-right direction;
a connecting shaft that connects the pair of left and right connecting portions to each other in the left-right direction;
has
3. The crane according to claim 1, wherein said connecting shaft constitutes said gantry upper end and supports said backstop distal end or said backstop proximal end. A backstop intermediate portion of the backstop set between the backstop base end portion and the backstop tip portion, and a front leg intermediate portion set between the front leg base end portion and the front leg tip portion. and a support member for supporting the backstop by connecting to each other, the tip of the backstop coming into contact with the other structure as the undulating body rises with respect to the crane body. 4. A crane according to any one of claims 1 to 3, further comprising a support member for maintaining the relative orientation of the backstop with respect to the gantry so that the the support member is removably attached to at least one of the front legs and the backstop to allow the backstop to change positions between a support position and a retracted position;
The supporting posture is a posture in which the backstop can support the hoisting body from behind, and the retracted posture is a posture in which the backstop is arranged so as to overlap the front legs more than the supporting posture. A crane according to claim 4. At least one end of the backstop distal end and the backstop proximal end has a pair of engaging pieces spaced apart in the vertical direction,
wherein, of the one structural portion and the other structural portion, the structural portion that supports the at least one end portion has a shaft portion that fits into a recess formed between the pair of engaging pieces. Item 6. The crane according to any one of Items 1 to 5. Engagement holes are formed in the tip portions of the pair of engagement pieces along a direction orthogonal to the left-right direction,
7. The apparatus according to claim 6, further comprising a retainer pin that prevents the shaft from being detached from the recess by inserting the shaft into the pair of engagement holes while the shaft is fitted in the recess. Crane as described.

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