JPH07109091A - Jib unit of tower crane - Google Patents

Abstract

PURPOSE:To aim at the facilitation of altering the full length of a jib by adjusting two insertional holes of upper and lower jibs with each other at both maximum elongative and minimum contractive positions of the upper jib and inserting a connecting pin into both of them for locking tight. CONSTITUTION:Four guide pipes 57 of a lower jib 41 are installed at two spots in and around both rear and front ends, and thereby they are able to lock an upper jib 42 surely at an elongative position or contractive position. When a jib unit 22 is elongated from the contracted state, two hydraulic cylinders 51 and 52 of a jib connecting pin detecher 50 are contacted, a connecting pin is pulled out of the guide pipes 57 of the lower jib 41, driving an elongating winch 43, and a wire rope 45 is wound in and simultaneously another wire rope 49 is delivered out of a contacting winch 44, then the upper jib 42 is pushed forward. Therefore the upper jib 42 is extruded up to a tip part of the lower jib 41, and pressure oil is fed to these hydraulic cylinders 51 and 52 at a position where both guide pipes 56, 56 and 57, 57 are accorded with one another, and the connecting pin is pushed out, whereby both these upper and lower jibs 42 and 41 are connected together through this pin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jib device, and more particularly to a jib device for a tower crane.

[0002]

2. Description of the Related Art A conventional tower crane will be described with reference to FIG. In the tower crane 1, a tower boom 4 is pivotally attached to an upper swing body 3 of a traveling machine body 2, and a jib 5 is pivotally attached to a tip end portion of the tower boom 4. The tower boom 4 is vertically erected by a hydraulically driven boom hoisting drum 7 via a tower support cable 6 as shown in FIG. Jib 5
Is connected to the jib undulating drum 11 via a jib support cable 8, a tower post 9, and a post support cable 10. The hook 12 hung from the tip of the jib 5 is connected to a lifting drum 14 via a lifting cable 13 and hoisted down. The jib 5 is an assembled type, and its entire length can be extended by interposing an extension jib 17 between the lower jib 15 and the upper jib 16 as shown in FIG.

The maximum working radius of the tower crane 1 is the jib 5
The upper limit of the standing angle of the jib 5 is 80 ° to 82 ° due to the weight balance limitation, and therefore the minimum working radius is also determined by the length of the jib 5. Therefore, for example, when the crane work is performed at a position closer to the turning center than the minimum working radius in the state where the extension jib 17 is mounted, the jib 5 to the extension jib 1
It is necessary to remove 7. Further, when the working radius is expanded from the state where the standard length jib is set, the work of assembling the extension jib 17 is required.

When changing the total length of the jib 5, the jib 5 is hung and fixed to the tower boom 4, and the tower boom 4 is hoisted down and the jib 5 is placed on a pedestal installed on the ground. Then, the auxiliary crane is used to remove the jib 5 from the tower boom 4, the jib 5 is disassembled, the extension jib 17 is attached and detached, and the jib 5 is attached to the tower boom 4 again to return to the working posture.

[0005]

The conventional tower crane requires a work of changing the jib according to the working radius, and requires equipment such as an extension jib and an auxiliary crane for changing the work, and requires a lot of labor and time. There is a drawback that it costs. Therefore, there is a technical problem to be solved in order to easily change the entire length of the jib to reduce the labor and the working time for changing the working radius and to improve the working efficiency. It aims to solve problems.

[0006]

DISCLOSURE OF THE INVENTION The present invention is proposed in order to achieve the above-mentioned object, and in a jib device pivotally attached to a tower boom of a tower crane, a lower portion pivotally attached to the tower boom. The upper jib is loosely fitted to the jib so that it can be expanded and contracted, and an expansion and contraction drive device such as a hydraulic actuator is interposed in the lower jib and the upper jib, and pin insertion holes are provided in the lower jib and the upper jib, and at least the upper jib is provided. It is formed so that the pin insertion hole of the upper jib and the pin insertion hole of the lower jib match at two positions of the maximum extension position and the minimum contraction position, and the connecting pin can be inserted into the pin insertion hole to fix the upper jib. The present invention provides a jib device for a tower crane characterized by the above.

[0007]

In the jib device of the present invention, the upper jib is slidably engaged with the lower jib. An expansion / contraction drive device such as a hydraulic motor is interposed between the upper jib and the lower jib to allow the upper jib to freely expand and contract. In addition, the upper jib and the lower jib are provided with pin insertion holes, and the pin insertion hole of the upper jib and the pin insertion hole of the lower jib are aligned at least at two positions of the maximum extension position and the minimum contraction position of the upper jib. And the upper jib can be fixed by a connecting pin. By extending or contracting the upper jib by the telescopic drive and fixing it with the connecting pin, the total length of the jib can be changed quickly and easily.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. The same parts as those used in the conventional example of FIG. 5 are designated by the same reference numerals. 1 and 2 show a tower crane 21, FIG. 1 shows the jib device 22 of the present invention in the most extended state, and FIG. 2 shows the shortest state. As shown in the figure, a tower boom 4 is pivotally attached to the upper swing body 3 of the traveling machine body 2, and a tower head 23 at the tip of the tower boom 4 and a boom bridle 24 are connected by a tower support cable 6. . Boom bail 2 provided on the boom bridle 24 and the upper swing body 3
Wire rope 2 wound around each sheave (not shown) with 5
One end of 6 is fixed to the boom bail support frame 27,
The other end is fixed to the boom hoisting drum 7 and the tower boom 4 is hoisted by the rotation of the boom hoisting drum 7.

The jib device 22 has a base portion pivotally attached to the tower head 23, and a tip end portion of the jib device 22 and a tower post 9 pivotally attached to the tower head 23 are connected by a jib support cable 8 to form a rear portion of the tower post 9. And jib bridle 28
And are connected by a post support cable 10. One end of the wire rope 30 wound between the jib bridle 28 and the jib bail 29 is fixed to the frame of the upper swing body 3 and the other end is fixed to the jib undulating drum 11 so that the jib undulating drum 11 rotates. The jib device 22 is raised or tilted. The lifting cable 13 of the hook 32 suspended from the sheave 31 at the tip of the jib device 22 is
The lifting drum 14 of the upper swing body 3 via the sheave 33 of
Is fastened to.

The jib device 22 has a pipe truss structure,
As shown in FIG. 3, the upper jib 42 is slidably fitted in the lower jib 41. A pair of winches 43 and 44 are provided near the base of the lower jib 41, and the wire rope 45 locked to one of the extension winches 43 is attached to the lower jib 41.
The direction of the sheave 46 is changed by the sheave 46 at the front portion of the upper jib 42, and the sheave is fixed to the front end portion of the lower jib 41 via the sheaves 47 and 48 at the rear portion of the upper jib 42. On the other hand, the other end of the wire rope 49 fixed to the contracting winch 44 is fixed to the front part of the upper jib 42, and one winch 43 or 44 is wound up while the other winch 43 or 44 is wound down. Thereby, the upper jib 42 can be extended or contracted.

Further, hydraulic cylinders 51, 52 of a jib connecting pin attaching / detaching device 50 are arranged at the rear end of the upper jib 42 in the left-right direction. The jib connecting pin attaching / detaching device 50 is shown in FIG.
As shown in FIG. 5, connecting pins 55, 55, 55, 55 are pivotally attached to the upper and lower ends of links 53, 54 for connecting the bottom side and rod side of the two hydraulic cylinders 51, 52, respectively. The tip end portions of the connecting pins 55, 55, 55, 55 are inserted into the horizontal guide pipes 56, 56, 56, 56 fixed to the pipe frame (not shown) of the upper jib 42, and the hydraulic cylinders 51, 52 are connected. When extended, the connecting pins 55, 55, 55, 55 will guide the guide pipes 56, 56,
56, 56 protrudes outward.

The lower jib 41 has connecting pins 55, 55, 5
Guide pipes 57, 57, 57 to which 5, 55 are fitted,
57, and the guide pipes 56, 5 of the upper jib 42.
6, 56, 56 and the guide pipes 57, 5 of the lower jib 41
After matching the positions of 7, 57, 57, connect pin 5
5, 55, 55, 55 are protruded from the contracted state shown in the upper half of FIG. 4 as shown in the lower half of FIG.
The upper jib 42 is fixed by inserting it into the guide pipes 57, 57, 57, 57.

As shown in FIG. 3, the guide pipes 57, 57, ... Of the lower jib 41 are arranged at two positions near the rear end and near the front end, and the upper jib 42 is extended or contracted. Can be securely fixed. Assembling the jib device 22 to the tower boom 4 is performed by tilting the tower boom 4 to the vicinity of the ground similarly to general jib assembling, and turning the jib device 22 upside down from the state shown in FIG. 23
And the jib device 22 is locked by the catch (not shown) of the tower boom 4. When extending the jib device 22 from the contracted state, the jib connecting pin attaching / detaching device 50
Of the hydraulic cylinders 51, 52 of the connecting pin 55,
55, 55, 55 to the guide pipe 57 of the lower jib 41,
57, 57, 57 are pulled out, the extension winch 43 is driven to wind the wire rope 45, and at the same time, the wire rope 49 is paid out from the contraction winch 44 to push the upper jib 42 forward. The upper jib 42 is extruded to the tip portion of the lower jib 41, and both guide pipes 56, 56, ...
The hydraulic cylinders 51, 52 at the positions where 7, 57, ...
Is supplied with pressure oil, and the connecting pins 55, 55, 55, 55 are extruded to pin-connect the upper jib 42 and the lower jib 41. Then, attach the jib support cables 8, 8 to the upper jib 42.
, The tower boom 4 is erected to reach the upright position, and then the jib catch is released to raise the jib device 22, and the work posture shown in FIG. 1 is obtained.

When the jib device 22 is contracted, the jib device 22 is tilted and fixed to the tower boom 4 by a jib catch, and the tower boom 4 is tilted and the jib device 22 is placed on a stand set on the ground. To do. After that, release the connecting pins 55, 55, 55, 55 in the same manner as described above,
The upper jib 42 is retracted and the connecting pin 5 is retracted at the retracted position.
Fixed by 5,55,55,55. Then, the jib support cable 8 is converted into a cable having a basic length, and the tower boom 4 is erected again, so that the working posture can cope with a small turning radius as shown in FIG.

The present invention should not be limited to the above-described embodiment, but hydraulic cylinders or the like may be used as the mechanism for extending and contracting the jib instead of the hydraulic winches 43 and 44.
Further, by disposing the guide pipes 57, 57, ... In the middle portion of the lower jib 41 in the front-rear direction, the fixing position of the upper jib 42 can be set in three or more stages, and the present invention has been modified. It goes without saying that it extends to things.

[0016]

The tower crane jib device of the present invention comprises:
Since it can be expanded and contracted as described in detail in the above one embodiment,
It can handle a wide working radius from a small radius to a large radius without using an extension jib, thus reducing the labor and cost required for transportation and storage of the extension jib. Also, the jib length can be easily changed without removing the jib device from the tower boom, so the labor required to change the jib length is reduced and the change work time is shortened compared to the conventional extension jib attachment / detachment work. Therefore, an auxiliary crane for reassembling work is not required, and work efficiency and cost efficiency are remarkably improved, and various effects are exhibited.

[Brief description of drawings]

FIG. 1 is a side view showing a tower crane equipped with a jib device of the present invention, with the jib device extended.

FIG. 2 is a side view showing a state in which the jib device of the tower crane shown in FIG. 1 is contracted.

FIG. 3 is an explanatory diagram of a jib device.

FIG. 4 is a cross-sectional view showing a connecting pin attaching / detaching device of the jib device, wherein an upper half shows a disconnected state and a lower half shows a connected state.

FIG. 5 is a side view of a conventional tower crane.

[Explanation of symbols]

 4 tower boom 21 tower crane 22 jib device 41 lower jib 42 upper jib 43 extension winch 44 contraction winch 45,49 wire rope 46,47,48 sheave 50 jib connecting pin attachment / detachment device 51,52 hydraulic cylinder 53,54 link 55 Connecting pin 56,57 Guide pipe

Claims (1)

[Claims] 1. A jib device pivotally attached to a tower boom of a tower crane, wherein an upper jib is loosely fitted to a lower jib pivotally attached to the tower boom to allow extension and contraction, and the lower jib and the upper jib are attached. An expansion / contraction drive device such as a hydraulic actuator is provided, and pin insertion holes are provided in the lower jib and the upper jib, and at least two positions of the upper jib maximum extension position and minimum contraction position are provided. The jib device of a tower crane, wherein the pin insertion holes of the above are formed so as to coincide with each other, and the connecting pin is inserted into the pin insertion holes so that the upper jib can be fixed.