JPH05321913A - Detachable part mounting structure - Google Patents

Abstract

PURPOSE:To improve clamping force by completely sinking the head of a standard hexagon socket head cap screw in a thinner member than the head of the screw while using the screw. CONSTITUTION:A washer faced hole 5 is provided in the leg section 2 of a drilling bit 1 fitted to a holder 7 in clevis, and a bushing 12 having a collar 13 and seat wall 14 is fitted in the washer faced hole 5 as illustrated in the right figure. The head of a screw 15 is locked to this bushing 12, and the clamping force from the head of the screw is applied to the leg section 2 through the bushing. Since the hexagon socket head of the standard hexagon socket head cap screw 15 is larger than the head of a flat head bolt, which is used when there is no bushing 12, and deep, rotary operation function can easily be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for a detachable part which enables easy and quick mounting and dismounting of parts within a narrow cross section, and is used, for example, for mounting a drill bit on a holder.

[0002]

2. Description of the Related Art In recent years, excavating heads for excavators, for example, excavating bits provided at the end of the screw of the earth auger of the casing front pipe for the all casing method are mainly removable, from the viewpoint of improving the operation rate of the machine. It started to occupy. In this detachable excavating bit, the shank portion is inserted into the holder fixed to the excavating head and fitted or clevis fitted, and the fitting portion is bolted.

[0003] In this case, the bolting is actually 3-169.
No. 57, that is, as shown in FIG. 3, the drill bit 1 has a seated bolt hole 16 having a large diameter on the inlet side.
, And the bolt 15 inserted into the hole and retained therein is screwed into the screw hole 6 provided in the holder 7, and as shown in FIG. There is one in which the holder-side rib 10 is sandwiched between the legs.

Incidentally, in these, the holder receives the excavating load applied to the bit so that the shearing force does not act on the bolt.

[0005]

The above-mentioned bolts 15 and 17 used for fixing the excavating bit have the head submerged in the object to be fixed in order to smooth the flow of sediment and prevent wear of the head. I need to leave. For that reason, the initial removable drill bit had a mounting structure as shown in FIG.
In this structure, the total thickness of the holder and the bit becomes considerably thicker than the wall thickness of the casing pipe P, etc., and the excavation resistance increases and the excavation speed decreases.

Therefore, the mounting structure of FIG. 4 using flat head bolts has been developed. However, in this flat head bolt, the opposite side dimension and depth of the operating hexagonal hole are both smaller than those of a normal hexagonal socket head bolt. In these small and shallow holes, the bolts are often rusted when they are removed, and the holes themselves may also be deformed.In such a case, the bolts cannot be turned and time-consuming gas fusing is required. become.

In the all-casing construction method,
A person goes down to the bottom of the hole and replaces the drill bit, but recently, deep hole drilling, such as digging a hole with a diameter of 1 m or more from the ground surface for 50 m or more, is increasing. In such cases, replacement by gas fusing is not implemented. hard.

Therefore, it is desired to use a standard hexagon socket head cap screw having an operation hole larger and deeper than the countersunk bolt so as to maintain its rotary operation function. However, this bolt has a head thickness of, for example, the leg portion of FIG. Since it is larger than the thickness of 2, it cannot be used when it is necessary to sink the head into the leg 2.

Therefore, the present invention eliminates the restriction of use of the standard bolt due to the thickness of the member to be tightened, and makes use of the advantage of the standard bolt that it can be operated more safely and surely than the flat head bolt, so that the detachability of the excavating bit or the like is improved. It is intended to provide a better component mounting structure.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a member, which is inserted and fitted or clevis-fitted and fixed by a bolt, on a member which is pressed by a head of the bolt. A bushing that is longer than the thickness of the member and has a collar on the outer periphery of the rear end that holds and locks in the seat groove of the member is detachably attached, and the head of the bolt is sunk into the bushing. I will receive it with this bushing.

[0011]

In the above structure, the tightening force from the bolt head is transmitted to the member to be pressed through the bushing, so that the bushing can be lengthened to compensate for the insufficient thickness of the member to be pressed. The standard bolt can be used even in the fitting portion as shown in FIG. Further, a part of the bushing is inserted into the mating member, but the bushing can be removed, so that the parts can be mounted and removed without any trouble.

[0012]

1 shows an embodiment of the present invention shown in FIGS. In the figure, P is a casing pipe (leading pipe) for the all-casing method, 7 is a holder welded to the pipe, and 1 is a drill bit attached to the holder with the mounting structure of the present invention. The holder 7 has cutout grooves 8 and 9 for receiving the leg portions 2 and 3 of the bit, and a rib 1 to be inserted into the clevis groove 4 of the bit.
0, and a hole 11 having a diameter larger than the body diameter of the bushing 12 is provided.

The leg portion 2 of the bit is provided with a seated hole 5 having a large diameter on the inlet side, and the other leg portion 3 is provided with a bolt 15
A screw hole 6 for screwing in is provided.

The bushing 12 is inserted into the hole 5 after fitting the bit 1 into the holder 7. This bushing is
The collar 13 provided on the outer periphery of the rear end is sized so as to fit in the large diameter portion on the inlet side of the hole 5 and is completely sunk in the leg 2, and is retained at the step (seat bottom) in the hole 5. The seat wall 14 provided on the inner periphery of the tip receives the head of the bolt 15 and transmits the tightening force of the bolt to the leg 2. The bolt 15 is a standard hexagon socket head cap screw. The bushing 12 has a distance from the rear end to the seat wall 14 that is equal to or greater than the head thickness of the bolt 15, and therefore the bushing 12
The length of the bushing is larger than the thickness of the leg portion 2, so that a part of the bushing penetrates the leg portion 2 and enters the hole 11, but the bolt 15 is removed and the bushing is extended to the position where the entry portion comes out of the hole 11. The bit can be removed from the holder by pulling out.

The length of the bushing 12 is the rib 10
Must be smaller than the sum of the thickness of the leg and the thickness of the leg 2. However, it is unlikely that the head of the bolt will stick out of the bit due to this regulation.

For example, in the case of a 40 mm wide bit, the thickness of the legs 2 and 3 is 12 mm, and the thickness of the rib 10 is 16.
mm is used for mounting with M16 bolts. With this design, the bolts that can be used are limited to flat bolts in the case of the conventional structure shown in FIG. On the other hand, in the structure of the present invention, since the length of the bushing 12 can be extended up to 28 mm, the standard hexagon socket head cap screw with a maximum head thickness of 16 mm can be completely depressed and used.

The drill bit having the above size specifications is M16.
All of the 22 bolts attached with the structure shown in Fig.
Of the 14 bolts, the hexagonal hole collapsed by the time the bolts were removed and attached twice, making it impossible to remove them. On the other hand, the standard hexagon socket head cap screw used in the structure of the present invention shown in FIG. 2 has the same M16, but there is no one that cannot be removed by two times of attachment / detachment. It could be confirmed.

In the embodiment, the attachment of the drill bit to the holder is taken as an example, but the parts to which the present invention is applied are not limited to the drill bit.

The positional relationship between the clevis groove and the rib provided corresponding to the component and the object to be mounted may be opposite to that shown in the drawing. The structure of the present invention is also effective when the plug and the socket are inserted and fitted and the fitting portion is bolted.

[0020]

As described above, according to the mounting structure of the present invention, by transmitting the tightening force to the member to be tightened through the removable bushing, the bushing compensates for the insufficient thickness of the member to be tightened. Since it is possible to use a hexagon socket head cap screw, it is possible to maintain the easy detachability of parts longer than the conventional structure by taking advantage of the bolt concerned.
The time and effort required for attachment and detachment will be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example of a mounting structure of the present invention.

FIG. 2 is a sectional view of the main part of the above.

FIG. 3 is a sectional view showing a conventional mounting structure.

FIG. 4 is a cross-sectional view showing another example of a conventional mounting structure.

[Explanation of symbols]

 1 Drill Bit 2, 3 Legs 4 Clevis Groove 5 Seat Hole 6 Screw Hole 7 Holder 8, 9 Notch Groove 10 Rib 11 Hole 12 Bushing 13 Tsuba 14 Seat Wall 15 Standard Hexagon Socket Head Bolt 16 Seat Bolt Hole 17 Flat Bolt P Casing pipe

Claims (2)

[Claims] 1. A mounting structure of a component, wherein a detachable component is inserted into or fitted to an object to be attached or clevis is fitted, and the fitting portion is bolted to connect the component to the object to be attached. To the member on the side where pressure is applied, attach a bushing that is longer than the thickness of this member and has a flange on the outer periphery of the rear end that is stored and locked in the seat groove of the member so that it can be removed. A mounting structure for detachable parts, characterized in that the bushing is submerged inside and received by the bushing. 2. The mounting structure for a detachable part according to claim 1, wherein the object to be attached is a holder provided on an excavating head of an excavator, and the detachable part is an excavating bit to be mounted on the holder.