JPH0834594A - Crane boom - Google Patents

Abstract

PURPOSE:To provide a crane boom which can easily lower the height of a crawler crane or the like. CONSTITUTION:A support frame 19 attached thereto with a guide sheave 4 QM around which a wire rope paid off from a winch is wound, is supported on the rear surface of the front end part of an upper boom 3b through the intermediary of a journal part 21 so as to be rotatable laterally of the upper beam 32B. In a crane workings attitude, the support frame 19 is secured to the upper boom 3B through the intermediary of a braking lever 23. During transportation, the support frame 19 is turned toward the outside edge of the upper boom 3A so that the guide sheave 4 is displaced to a transportation attitude position. Thereby, it is possible to lower the height of the transportation attitude.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a crawler crane,
Crane booms such as truck cranes.

[0002]

2. Description of the Related Art FIG. 4 shows a working posture of an example of a crawler crane. A revolving unit 2 is rotatably mounted on an endless track type traveling unit 1, and a lower boom 3 is provided in front of the revolving unit 2.
The boom 3 including the upper boom 3A and the upper boom 3B is attached so as to be able to be raised and lowered. A guide sheave 4 is attached to the rear surface of the tip of the upper boom 3B, and a point sheave 5 is attached to the front surface of the tip. As shown in FIGS. 5 and 6, the guide sheave 4 is supported via a pin 7 by a bracket 6 fixed to the tip rear surface of the upper boom 3B. The hoisting rope 9 unwound from the winch 8 installed on the revolving structure 2 includes a guide sheave 4 and a point sheave 5.
And a hook 10 is hung on it. An undulating lobe 12 fed from a winch 11 installed on the revolving structure 2 includes a hanger 14 connected to the top of an A frame 13 installed on the rear of the revolving structure 2 and a bridle 16 connected to the rear ends of the guy lines 15. It is hung around with. The upper end of the guy line 15 is the upper boom 3B.
Is connected to the tip of the.

FIG. 7 shows a posture in which a crane is carried on a trailer 18 which is towed by a trailer truck 17 to transport the crane on the premises. This transportation on the premises is often carried out with the boom 3 still attached in order to omit the wire rope and the like and shorten the time. In this case, the transport height H
Is determined by the mounting position of the guide sheave 4.

[0004]

The above-mentioned transport height H is
When the transportation limit is exceeded, the upper boom 3B needs to be disassembled because the bracket 6 is fixed, which is troublesome. The present invention has been made in view of the above, and an object of the present invention is to provide a crane boom that can easily lower the position of the guide sheave in the transportation posture to reduce the transportation height.

[0005]

[Means for Solving the Problem] On the back surface of the tip of the boom,
The guide sheave is attached and the support frame is supported so as to be rotatable in the lateral direction of the boom. In the crane working position, the guide sheave is held in the vertical direction, and in the transporting position, the support frame is rotated to lie the guide sheave against the boom and displace it to the transport position. In the crane work posture, the support frame is stopped by the boom by the fixing means.

[0006]

The transport height can be reduced by turning the support frame and laying down the guide sheave.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
This will be described below.

A support plate 17 having a notch 17a in the middle is integrally attached to the rear surface of the tip of the upper boom 3B, and a bracket 18 is provided at the front and rear of the support plate 17, respectively.
Are fixed with bolts. The guide sheave 4 is supported on the middle portion of the support frame 19 via pins 20.
A shaft portion 21 is integrally provided at each of a front end portion and a rear end portion of the support frame body 19, so that the shaft portion 21 can rotate.
It is supported by the bracket 18. A bracket 22 is fixed near one corner of the support plate 17, and one end of a stop lever 23 is connected to the bracket 22 by a pin 24. The other end of the stop lever 23 has a pin 25.
Is connected to the end plate portion of the support frame body 19. The bracket 18, the support frame 19, the guide sheave 4, the bracket 24, the stop lever 23, etc. are also installed on the right side of the center line C in FIG. 2, but they are not shown.

1 and 2 show a state in which the crane is in a working position. The support frame 19 is fixed to the support plate 17 of the upper boom 3B via a stop lever 23, and the pin 20 of the guide sheave 4 is horizontal. It has become. That is, the guide sheave 4 is held vertically.

At the time of transportation, the pin 25 is removed, the connection between the stop lever 23 and the support frame 19 is released, and the support frame 19 is released.
When is rotated about the shaft portion 21 toward the outer edge side of the upper boom 3B, the support frame 19 and the guide sheave 4 are held in the transportation posture position shown in FIG. 3 by their own weight. The position of the shaft portion 21 is set to be such. As a result, the transport height becomes lower than that of the conventional one by h. Arrow L in FIG.
Indicates the rotation direction of the left support frame 19 and the guide sheave 4, and the arrow R indicates the rotation direction of the right support frame and the guide sheave (not shown).

The supporting frame 19 can be easily fixed in the transporting posture position by the stop lever 23 or other means.

[0012]

According to the present invention described above, the transport height of a crawler crane or the like can be easily reduced by rotating the support frame while the upper boom is still connected to the lower boom. .

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention,

2 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view showing a transportation posture in which the support frame is rotated to the left outer edge side of the upper boom from the state of FIG. 2;

FIG. 4 is a side view showing a crane working posture of an example of a conventional crawler crane;

FIG. 5 is a perspective view showing an upper boom of a conventional crawler crane,

FIG. 6 is an enlarged view taken along line BB of FIG.

FIG. 7 is a side view showing a transportation posture of the crawler crane of FIG.

[Explanation of symbols]

 3B Upper boom 4 Guide sheave 17 Support plate 18 Bracket 19 Support frame 20 pin 21 Shaft part 22 Bracket 23 Stop lever 24 pin 25 pin

Claims (2)

[Claims] 1. A support frame body having a guide sheave for hanging a wire rope extended from a winch attached to a rear end portion of the boom is supported so as to be rotatable in a lateral direction of the boom. By rotation, the guide sheave can be displaced between the crane working posture position and the transporting posture position, and a fixing means for stopping the support frame for holding the guide sheave in the crane working posture position is provided. Crane boom characterized by what it has. 2. A fixing means for restraining the support frame is composed of a bracket attached to the boom and a restraining lever having one end connected to the bracket by a pin and the other end connected to the support frame by a pin. The crane boom according to claim 1, which is configured.