JPS5938559Y2 - Excavator bit mounting device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement of a bit mounting device for an excavator.

As shown in Figures 1 and 2, conventional bit mounting devices for excavators are as follows: Outline and Disadvantages of the Conventional Bit Mounting Devices A large number of bit holders (b) are attached to the cutter head (a) of a tunnel excavator that excavates rock or hard soil.
is attached by welding, and bit C is inserted into the hole of bit holder B.
is installed.

The bit 3 is a consumable item and is screwed and fixed with a bolt d so that it can be replaced.

The large hole of bit C in bit holder b and bit holder b
The upper surface of the bit is also slightly worn and sag, and even if the bit C is removed, there will be some looseness.

Also, the reaction force F generated on the bit C during excavation is caused by the bit holder b
When the bit holder b is new, the upper surface of the bit holder b and the large hole in the bit C can sufficiently absorb the reaction force, but when the above-mentioned backlash occurs, the reaction force of the force F acts on the bolt d.

The force acting on the bolt d is shockingly large, and even if the size of the bolt d is increased somewhat, it will break immediately.

Furthermore, since the bit holder b is attached to the cutter head a by welding, it is not possible to immediately replace it if it becomes loose.

Therefore, the object of the present invention is to provide a bit mounting device for an excavator that prevents force from acting on the bolt even if there is some looseness, and that serves only to prevent the bolt from being pulled out.

The feature of this invention is that a pull-out stopper made of rubber, synthetic resin, etc. that can expand and contract to a certain extent is incorporated into the bolt attachment part, which is a recess formed on the side of the bit. By positioning the tip of the bolt that is screwed into the bit holder, even if the bit holder wears out or becomes loose and there is play when the bit is removed, the force due to large excavation resistance will be applied directly to the bit mounting bolt. This reduces bolt breakage accidents and bit holder replacement.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view showing an embodiment of the present invention, FIG. 4 is a sectional view taken along the line IV--IV in FIG. 3, and FIG. 5 is a sectional view showing its operating state.

In Figures 3 and 4, which shows a bit mounting device for a tunnel excavator that excavates rock or hard soil by rotating a cutter head with a large number of bits attached, 1 is a cutter head, and 2 is a welding etc. Bit holder installed in large numbers, 3
is a bit, and a bit 3 having a rectangular insertion portion 3a is inserted into the rectangular hole 2a of the bit holder 2.

4 is a bolt, 5 is an elastic removal stopper piece,
A bolt 4 with a rod-shaped tip 4a is screwed into the screw hole 2b on one side of the bit holder 2, and a round hole 5a is formed in the rectangular recess 3b formed on the side of the bit 3. A bit removal stopper 5 made of resin or the like is incorporated, and the tip 4a of the bolt 4 is inserted into the round hole 5a of the removal stopper piece 5, and the bit 3 is attached.

It is important that the rod-shaped part of the bolt tip 4a does not completely fill the hole 5a of the removal stopper piece 5, leaving some space. Therefore, the need for 6 volume changes arises, and the freedom of expansion and contraction is greatly reduced.

Bit 3 is a consumable item and should be replaced directly, but bit holder 2 is attached to cutter head 1 for customer use, so bit 3
If the upper surface of the holder 2 where the shoulder of the bit 3 contacts the large hole or the shoulder of the bit 3 is worn or bent, the bit 3 may become damaged.
A gap is created between the shoulder of the bit holder 2 and the upper surface of the bit holder 2, and between the bit insertion part and the hole of the bit holder 2.

However, in the present bit mounting device, even if a downward excavation reaction force occurs in such a state, no impact force or the like will directly act on the bolt 4 due to the expansion and contraction of the pull-out stopper piece 5.

This may lead to an extremely dangerous accident where the bolt 4 breaks (the bolt 4 breaks and the bit 3 jumps out from the rotating cutter head 1).

), and the number of replacements of the holder 2 is reduced.

As described above, according to the present invention, a bit holder fixed to a cutter head, a recess formed on the side thereof, a bit attached to the bit holder, a hole formed and assembled in the bit recess. By using an elastic removal stopper piece and a bolt whose tip is inserted into the hole of the removal stopper piece and screwed into the bit holder, no impact force is applied to the bolt and the bolt is not cut. There will be no more accidents and the number of times the bit holder needs to be replaced will be reduced.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing a conventional excavator bit mounting device;
Figure 2 is a sectional view taken along the line ■-■ in Figure 1, Figure 3 is a sectional view showing an embodiment of the present invention, Figure 4 is a sectional view taken along the line 11V-IV in Figure 3, and Figure 5 shows its operating state. FIG. 1... Cutter head, 2... Bit holder, 2a... Rectangular hole, 2b... Screw hole, 3... Bit, 3a...Insertion part, 3b...Recessed part, 4...Bolt,
4a... Bolt tip, 5... Removal stop piece.

Claims (1)

[Scope of utility model registration request] A bit holder fixed to the cutter head, a bit having a recess formed in the side thereof and installed in the bit holder, an elastic removal stop having a hole formed and incorporated in the bit recess; A bit mounting device for an excavator, comprising a bolt whose tip end is inserted into a hole of the removal stopper piece and is screwed into the bit holder.