JPS6129792Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frame structure of a revolving upper body in a construction machine, and more particularly to a frame structure suitable for a revolving upper body of a three-point support pile driver equipped with a rear beam.

Conventionally, the frame structure of an upper revolving body in a construction machine has main members 2, 2 provided on both sides of a bottom member 1, as shown in FIGS. 1 and 2. A plurality of connecting members 3 are attached to connect the main members 2 at intervals, and a rear beam 4 is made to protrude to the side of the rear end of the main members 2, 2.

The above-mentioned frame structure is applied, for example, to an upper revolving body 10 of a three-point support type pile driver as shown in FIGS. 3 and 4. That is, the three-point support type pile driver has the upper rotating body 1 pivotably mounted on the lower traveling body 11.
0, and a leader 13 is attached to the front bracket 12 provided on the upper revolving body 10,
The rear beam 4 of the upper revolving body 10 and the leader 13
In addition, the backstay 1 supporting the leader 13
4 is installed. At the top of the leader 13,
A pile hanging sheave 15 is installed. The pile 17 is attached to the leader 13 by the pile lifting rope 16 lifting the pile 17 via the pile lifting sheave 15. Note that 18 is a winch.

By the way, when attaching the pile 17 to the leader 13 in a three-point support type pile driver, if you try to lift the pile 17 from the side of the revolving upper structure 10, as shown in FIG. A lateral force acts on the tip side of the leader 13,
This force P is transmitted via the backstay 14,
Strong forces in opposite directions on both rear beams 4
F ₁ and F ₂ are required.

However, in the conventional frame structure of an upper revolving body, the rear beam 4 is made to protrude to the side of the rear end of the main members 2, 2, and the main members 2, 2 are connected by the connecting member 3, so that the pile 17 and strong forces F ₁ in opposite directions are applied to the left and right sides of the rear beam 4.
When F ₂ is applied, elastic deformation occurs in the main members 2, 2, and torsional torque acts on the connecting member 3. Therefore, stress concentrates on the welded joint of the connecting member 3,
There is a problem that cracks occur in the welded joint.

To solve the above problem, it is conceivable to attach the connecting members 3 in a sash shape. However, in this case, not only does the shape of the connecting member 3 become complicated, but also it takes time and effort to weld the joints of the connecting members, and it becomes difficult to arrange the equipment to be installed between the connecting members. be.

An object of the present invention is to provide a frame structure that can solve the problems of the prior art.

In order to achieve the above object, the frame structure of the present invention includes a bottom member, a main member provided on both sides of the bottom member, a plurality of connecting members connecting the two main members, and a frame structure provided on the sides of the main member. The vehicle is characterized in that the vehicle is provided with a projecting rear beam, all of the connecting members are formed of members having a hollow cross section, and the connecting member near the rear beam is constructed of a member having a larger moment of inertia than the other connecting members.

An embodiment of the present invention will be described below with reference to FIGS. 5 and 6.

5 and 6, the frame structure of the upper revolving body according to the present invention includes a bottom plate 1, main members 2, 2 provided on both sides of the bottom plate 1, and two main members 2, 2 connected at intervals. A plurality of connecting members 3 ₁ to 3 _o
and a rear beam 4 that juts out to the side of the main members 2, 2.
It is equipped with

The connecting members 3 ₁ to 3 _o are formed of members having a hollow cross section. For example, the connecting member 3
₁ to 3 _o are formed into a rectangular cross section. Also, among the connecting members 3 ₁ to 3 _o , the rear beam 4
The connecting member 3 _o located near the connecting member 3 o is made of a member having a larger moment of inertia than the other connecting members 3 ₁ to 3 _o-1 . That is, the connecting member _3o closest to the rear beam 4 is formed to have a larger cross-sectional area than the other connecting members.

The frame structure configured as described above is applied to the upper revolving body 10 of a three-point support type pile driver, and the pile 17 is driven by the pile driver to the upper revolving body 10 as shown in FIGS. 3 and 4. Try to lift it from the side. Then, strong forces F ₁ and F ₂ in opposite directions act on both rear beams 4, so that the main members 2,
2 are displaced up and down, and torsional torque acts on the connecting members 3 ₁ to 3 _o .

However, in the present invention, since the connecting member 3 _o near the rear beam 4 is constructed of a member having a larger second moment than the other connecting members 3 ₁ to 3 _o-1 ,
The connecting member 3 _o absorbs the force F ₁ and reduces the transmission of torsional torque to the other connecting members 3 ₁ to 3 _o-1 . Furthermore, since the other connecting members 3 ₁ to 3 _o-1 are also formed of members with hollow cross sections, these connecting members disperse stress and reduce torsional torque. Therefore, a particularly large force is applied to one rear beam 4.
Even if F ₁ acts, the transmission of torsional torque by the connecting members 3 ₁ to 3 _o is reduced, so that the frame maintains sufficient strength. Moreover, since stress is not concentrated at the welded joints of the connecting members 3 ₁ to 3 _o due to the reduction in torsional torque, there is no risk of cracks occurring in the welded joints.

Although the illustrated embodiment shows an example in which the connecting members 3 ₁ to 3 _o are formed in a rectangular cross section, the connecting members may be formed in other hollow shapes such as a cylindrical shape in the present invention.

As is clear from the above embodiments, according to the present invention, even if strong forces in opposite directions are applied to both rear beams, the torsional force can be sufficiently absorbed and cracks can be prevented.

[Brief explanation of the drawing]

Figure 1 is a side view showing the frame structure of a revolving upper body in conventional construction equipment, Figure 2 is a sectional view taken along the - line in Figure 1, and Figure 3 is a three-point view to which the frame structure of a conventional revolving upper body is applied. FIG. 4 is an overall side view showing the supported pile driver, and FIG. 4 is an explanatory front view of FIG. 3.
FIG. 5 is a side view showing the frame structure of the upper revolving body in the construction equipment of the present invention, and FIG. 6 is a sectional view taken along the line -- in FIG. 1... Bottom member, 2... Main member, 3 ₁ ~ 3 _o ...
Connecting member, 4... Rear beam.

Claims (1)

[Scope of utility model registration request] a bottom member; a main member provided on both sides of the bottom member;
A plurality of connecting members connecting the two main members at intervals, and a rear beam projecting to the side of the main member, all of the connecting members are formed of hollow cross-section members, and a connection near the rear beam is provided. A frame structure of an upper revolving body in a construction machine, characterized in that a member is constructed of a member having a larger moment of inertia than other connecting members.