JP2593040Y2 - Shank rod damage prevention structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a shank rod used for boring work such as ground improvement work.

[0002]

2. Description of the Related Art When performing boring work in earth anchor work or ground improvement work, etc., the impact force and rotational force from a top hammer are applied to the tip of the tip through a shank rod, cleaning adapter, extension rod, etc. The method of transmitting to bits is well known.

[0003] However, the hardness of the ground is not constant, and when rocks and the like are sometimes mixed in the soil, when the tip of the tip bit collides with the rock or the like, a large reaction force is generated from the tip, and the reaction force is reduced. The impact force of the hammer main body transmitted by the shank rod collides with the shank rod, and as a result, the shank rod may be broken.

[0004] When the shank rod is broken, it becomes difficult to transmit the striking force and the rotational force thereafter. Therefore, the work of replacing the shank rod must be performed. Prolongs, increases operating costs, and causes various other disadvantages.

[0005] In addition, in 1983, utility model application publication No. 318
Japanese Patent Application Laid-Open Publication No. H11-133873 discloses a technique in which a buffer is provided on a tapered screw portion when a bit is screwed onto a rod. However, such a known technique facilitates attachment and detachment with a screw, and does not reduce the impact force of the shank rod and does not prevent damage.

Further, Japanese Patent Application No. 1-174489 discloses a technique for cooling by supplying water to a coupling thread portion between a shank rod and a cleaning adapter.
However, such a known technique does not reduce the impact force.

[0007]

Therefore, according to the present invention, the impact force from the top hammer can be appropriately transmitted to the tip of the shank rod, and the impact force is reduced even if the bit collides with the hard ground. It is an object of the present invention to provide a shank rod damage prevention structure that can prevent breakage of the shank rod.

[0008]

According to the present invention, a bit (1) having a plurality of excavating tips (T) attached to a tip thereof is attached to an inner short rod (3), and the inner short rod is provided. (3) is connected to a cleaning adapter (5) via an extension rod (4), and the cleaning adapter (5) is a structure for preventing breakage of a shank rod connected to a top hammer via a shank rod (6). In the bit (1)
Is fixed to the shoulder of the mounting screw of the inner short rod (3) via a liner plate (2) made of a resin material formed in a ring shape, and the spline shaft (6) of the shank rod (6) is fixed.
a) a spline hole (5b) of the cleaning adapter (5) into which the spline shaft (6a) is fitted; A rich liner plate (7) is provided. The liner plate is made of a material having high elasticity, excellent impact resistance and heat resistance and having chemical resistance, for example, Teflon rubber, and has a thickness of 2 m.
m is preferable.

[0009]

According to the structure for preventing breakage of the shank rod according to the present invention, the striking force from the hammer body is transmitted from the shank rod to the cleaning adapter via the liner plate, and further via the extension rod. Reach the tip drill bit. And even if the tip of the bit hits a rock or the like and the reaction force is transmitted to the cleaning adapter and repels the impact force from the hammer body in the adapter, the excessive reaction force or impact force becomes excessive. The (repulsive force) is absorbed and reduced by the liner plate made of an elastic material. As a result, breakage of the shank rod is prevented.

In this case, the thicker the liner plate is, the higher the ability to absorb and mitigate the impact is. On the other hand, if the liner plate is too thick, an unnecessarily large space is formed between the shank rod and the cleaning adapter, and the liner plate easily breaks. It is preferable to do so. If the thickness is more than necessary, the liner plate interferes with the chamfered or rounded portion formed on the inner wall surface of the cleaning adapter, thereby preventing the shank rod from being sufficiently inserted into the cleaning adapter.

In the case where the drilling bit provided at the tip of the boring equipment is constituted by providing a ring-shaped resin material liner plate at the shoulder of the mounting screw provided at the shank, the drilling bit is provided at the shank. A liner plate made of a resin material is provided at the shoulder of the mounting screw, that is, at the boundary (seam) between the bit and the short rod. Due to the self-lubricating property of the resin material, the bit and the short rod are separated at the boundary. There is no adhesion.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a bit 1 is connected to a short rod 3 via a liner plate 2 formed of a Teflon plate.
It is fixed to. And inner short rod 3
Is connected to a cleaning adapter 5 via an extension rod 4, and the adapter 5 is connected to a top hammer (not shown) via a shank rod 6. The tip of the shank rod 6 has a thickness of 2 m.
There is provided a liner plate 7 formed of a disc made of m. Teflon rubber. In FIG. 1, a plurality of excavating chips indicated by reference symbol T are attached to the tip of a bit 1.

FIG. 2 shows an example of the shank rod 6.

Referring also to FIG. 3 and FIG.
A spline shaft 6a is formed at one end of the shank rod 6, and is slidably fitted into a spline hole 5b provided in the cleaning adapter 5. The liner plate 7 is provided on the end face of the spline shaft portion 6a of the shank rod 6.

The liner plate 7 is formed to have a thickness of 2 mm or less so as not to interfere with the radius 5r of the inner wall surface of the cleaning adapter 5.

The impact force from a drop hammer (not shown) is transmitted from the shank rod 6 to the cleaning adapter 5 via the liner plate 7. Where bit 1
Even if (FIG. 1) collides with a hard rock or the like to generate a reaction force, the reaction force is absorbed and reduced by the liner plate 7. Therefore, there is no possibility that the reaction force and the impact force from the hammer collide and break the shank rod 6.

[0018]

[Effects of the Invention] Since the present invention is configured as described above, breakage of the shank rod is prevented and boring work can be performed efficiently. As a result, various costs in the boring operation are saved.

Further, as for the excavation bit provided at the tip of the boring equipment, an annular resin-made liner plate is provided on the shoulder of the mounting screw provided on the inner short rod. Will not adhere at the border.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a boring device using the present invention.

FIG. 2 is a side view of the shank rod used in the present invention.

FIG. 3 is an enlarged view showing a spline hole of the cleaning adapter used in the present invention.

FIG. 4 is an enlarged view showing a splice shaft portion of the shank rod used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inner bit 2 ... Liner plate 3 ... Inner short rod 4 ... Extension rod 5 ... Cleaning adapter 6 ... Shank rod 7 ... Teflon sheet

Claims (1)

(57) [Scope of request for utility model registration] A bit (1) having a plurality of excavating tips (T) attached to a tip thereof is attached to an inner short rod (3), and the inner short rod (3) is provided.
Is connected to a cleaning adapter (5) via an extension rod (4), and the cleaning adapter (5) is connected to a top hammer via a shank rod (6). (1) is inner short rod (3)
The spline holes (6) of the cleaning adapter (5) which are fixed to the shoulders of the mounting screws through a liner plate (2) made of a resin material formed in an annular shape and into which the spline shaft (6a) of the shank rod (6) fits. 5b), and an end face of the spline shaft (6a) is provided with a liner plate (7) rich in elasticity so as not to interfere with the round portion (5r) of the inner wall surface of the cleaning adapter (5). To prevent the shank rod from being damaged.