JPH0333784Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention relates to a strut device for earth retention shoring that is applied to excavated trenches.

[Conventional technology]

When burying gas pipes, water and sewage pipes, electric wires, etc., a trench of the required depth and width is first excavated, and work is first carried out to prevent the walls of both excavated trenches from collapsing. In other words, shoring is installed between the excavated walls to ensure safety.The most commonly used strut device for this purpose is a device using a pressure cylinder as shown in Figure 5. .

This causes the pressing force due to the extension of the piston rod 2 of the pressure cylinder 1 to act on the sheet pile 6 via the cylinder pad 3, rod pad 4, and upright 5.

[Problem that the invention attempts to solve]

In a strut device using a pressure cylinder as described above, when the capacity (pressure/discharge amount) of the hydraulic pump is constant, the smaller the cross-sectional area of the cylinder, the higher the extension speed and the better the workability. However, on the other hand, if the cross-sectional area of the cylinder is small, especially a long cylinder, the buckling strength will be reduced and it will be easier to bend.

One countermeasure for this problem is firstly to increase the diameter of the cylinder, and secondly to increase the wall thickness of the cylinder. However, increasing the diameter of the cylinder will slow down the extension speed of the piston rod, leading to a deterioration in workability. Furthermore, an increase in wall thickness not only results in excessive strength but also increases weight, which poses a problem in terms of handling.

This invention was made to solve these problems, and the purpose is to provide a strut device that has the cross-sectional area of the cylinder as small as possible and has the desired buckling strength. be.

[Means for solving problems]

The strut device according to this invention has a reinforcing oversleeve fitted onto the outer peripheral surface of a hydraulic cylinder.

[Effect]

In this invention, the strength of the cylinder is increased by the fitted oversleeve, so
It becomes possible to use cylinders with good workability.

〔Example〕

FIG. 1 is a partially cutaway front view of an embodiment of this invention. In the figure, 7 is an oversleeve that is precisely fitted over the outer peripheral surface of the cylinder 1 over the entire length of the cylinder 1. Cylinder part 3
In order to firmly fix the cylinder 1 to the cylinder 1, a lock nut 8 is screwed onto the tip of the cylinder 1 and tightened. Note that there are other methods for fixing the oversleeve 7 to the cylinder 1, such as driving a fixing pin, and there are no particular restrictions. The oversleeve 7 may be made of a pipe material having the required strength, but as an alternative to this, as illustrated in FIG.
A plurality of longitudinal ribs 10 are attached to the inner cylinder 9.
A concentric outer cylindrical body 11 integrally formed with a pine nut pull shape in cross section, or a cylindrical body 12 having a plurality of convexities on the outer circumferential surface that is in close contact with the outer circumferential surface of the cylinder 1, as illustrated in FIG. Furthermore, as illustrated in FIG. It is sufficient to appropriately select the one that is closely related to the above. If these oversleeves 7 are made of extruded aluminum, the desired strength can be ensured and the weight can be reduced, which can be expected.

In addition, in FIG. 1, 14 indicates the piston rod 2.
One end of the oversleeve 7 is fitted onto the outer periphery of the oversleeve 7, and the other end is connected to the tip of the piston rod 2 via a connecting pin 15 and a rod pad 4.

[Effect of idea]

As explained above, this invention has a simple structure in which an oversleeve is fitted around the outer periphery of the cylinder, so that a long cylinder with a small cross-sectional area can be reinforced without changing its workability. In other words, as proven by Euler's equation, doubling the minimum cross-sectional secondary radius quadruples the buckling strength, which is a significant effect. Note that this invention can be easily applied to existing devices, and all other parts are compatible by simply adding the oversleeve and the lock nut that fixes it.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of an embodiment of this invention; FIGS. 2, 3, and 4 are sectional views showing embodiments of an oversleeve fitted over a cylinder; FIG. 5 is a front view showing a conventional strut device and its mode of use. 1...Cylinder, 2...Piston rod, 7
...Over sleeve.

Claims (1)

[Claims for Utility Model Registration] (1) In a strut device using a pressure cylinder,
A strut device for earth retaining shoring, characterized in that an oversleeve is fitted onto the outer circumferential surface of the pressure cylinder so that the inner circumferential surface of the oversleeve is in close contact with the outer circumferential surface of the pressure cylinder. (2) The strut device for earth retaining shoring according to claim 1, wherein the oversleeve has a pine-nut pull shape in cross section. (3) The strut device for earth retaining shoring according to claim 1, wherein the oversleeve has a plurality of protrusions arranged on its outer peripheral surface. (4) Utility model registration claim 1, characterized in that the oversleeve is provided with a plurality of convex shapes on its inner peripheral surface so that the inner end surface of the convex shapes is in close contact with the outer peripheral surface of the pressure cylinder. A strut device for earth retention shoring as described in Section 1.