JP2910509B2 - Drilling blade for construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling blade for construction machinery,
In particular, the present invention relates to a drilling blade used for an earth drill bucket and a rivers circulation drill.

[0002]

2. Description of the Related Art A method of directly fixing a drilling blade attached to the bottom of a bucket of an earth drill to a bottom plate (bottom lid) of a drilling bucket by welding or the like is adopted. This is because the conventional earth drill has a relatively low output and does not require frequent replacement of the blade because it mainly excavates soft formations such as earth and sand.

However, recently, a large-output earth drill for the purpose of constructing a deep pile with a large diameter and excavating an existing underground buried object in accordance with a rebuilding of a building, etc. has emerged, and the cutting edge load is large. Excavation has begun and the frequency of excavation blade replacement has increased due to increased chipping and early wear.

[0004] In the case of direct fixing by welding or the like, the time required for one excavation blade exchange becomes long, and if the exchange frequency is increased, the operation rate of the excavator is greatly reduced.

[0005] Therefore, it has been studied to adopt a detachable method used in all casing methods and the like for this kind of excavating blade.

As this detachable cutting blade, for example, the one shown in FIG. 6 can be considered. In this structure, the holder 1 is provided with recesses 2 and 2, and the drill bit 6 is provided with tail plates 7 and 7 that fit in the recesses 2 and 2 and the groove 8 that receives the partition 3 between the recesses 2 and 2, respectively. Bolt 11
Is to be concluded.

[0007]

The load at the time of digging of the digging blade is represented by a rotational force Q and a pressing force F shown in FIG.
And the lateral load S applied from the borehole wall surface.

In the case of the excavating blade using the detachable structure shown in FIG. 6, the contact portion between the front surface 4 of the holder and the shoulder 9 of the bit is not affected by the rotational force Q and the pressing force F among the above four forces. (FIG. 7
(A or A 'portion) becomes a fulcrum, and the bit rotates until the inner surface of the tip of the tail plate 7 hits the partition wall 3 and receives a load at this position. However, according to the manner of receiving the load, the bending force is concentrated on the base of the tail plate 7 and the tail plate is easily damaged at the position of the line a in FIG. Further, the groove 8 is formed by the above-described bending force.
The bolt 11 tends to be damaged due to the load since the mouth is opened.

Since the excavation blade is provided at the intake of the earth and sand, it should be designed as compact as possible so as not to obstruct the flow of the earth and sand. Since it is necessary to increase the thickness and the thickness of the bolts to provide strength, it is difficult to achieve compactness.

An object of the present invention is to eliminate the load concentration on a local part by receiving loads from various directions in each part of a fitting surface of a holder and a bit, thereby realizing a compact excavating blade. Is an issue.

[0011]

In order to solve the above-mentioned problems, the present invention has made the following improvements to the excavating blade having the structure shown in FIG. That is, a widened extension protrusion (5 in FIGS. 1 and 5) protruding forward from the front surface of the holder is added to the partition wall 3 of the holder shown in FIG. 6, and the groove 8 on the excavation bit side extends to the portion of the extension protrusion. To accept the depth.

[0012] digging edge of Figure 6, the lateral load S in FIG. 5, the contact portion of the holder front and bit shoulder {5 of (a) B, to B '
Corresponding part {contact part between tail plate side surface and recess inner surface}
(A) is received by a portion ｝ corresponding to C and C ′.

In addition, for the combined excavating force P shown in FIG.
(A) is received at a portion ｝ corresponding to BB ′ .

In this regard, the drill bit of the present invention is the same.

On the other hand, in the case of the structure of FIG. 6, the rotational force Q and the pressing force F correspond to the portions corresponding to D and D 'in FIG. 5B (FIG. 7).
In the present invention, as shown in FIG. 5, the extension protrusion 5 of the partition 3 is fitted in the groove {E, E ′ in FIG. 5B}. Receive at The extension protrusion 5 is wider than the tail plate 7. Further, the fitting portion between the extension protrusion 5 and the groove 8 serves as a rotation fulcrum when the bit is rotated by Q and F forces.
Since it is closer to the point where the load is applied than (the DD ′ portion in FIG. 5B), the amplified transmission of the load does not occur unlike the structure of FIG. 6 in which the bit rotational force is amplified by the leverage principle and applied. Therefore, even if the extension projection is not thickened, the projection can be prevented from being damaged.

Further, since the forces of Q and F are received by the fitting portions of the extension projections, no force is applied to the tail plate of the bit and the connecting shaft of the bit and the holder, so that it is not necessary to increase the thickness of the tail plate. Even small diameter bolts and spring pins are sufficient.

These factors effectively work to realize a compact detachable drilling blade.

[0018]

FIG. 1 shows an embodiment of the present invention. 1 is a holder, 2 is a concave portion provided on the upper and lower surfaces of the holder by opening the upper surface and the front surface, and the lower surface and the front surface, and 3 is a partition wall left between the upper and lower concave portions. Has a H-shaped cross section. Reference numeral 5 denotes an extension protrusion that projects from the front surface 4 of the holder and has the same width as the width of the holder provided at the tip of the partition wall.

Reference numeral 6 denotes an excavating bit having a cemented carbide blade fixed to the tip, 7 a tail plate to be housed in the recess 2, 8 a groove into which the partition wall 3 is inserted, 9 a shoulder to be brought into contact with the front surface of the holder, and 10 a partition wall 3. And a shaft hole provided corresponding to the tail plate 7. Shaft hole 1 on bit side
Numeral 0 designates a hole provided in the upper tail plate 7 for a seat for dropping a bolt head, and a hole provided in the lower tail plate as a screw hole. The excavation bit 6 inserted and fitted into the hole is prevented from coming off.

Since the drilling load is not transmitted to the connecting shaft of the bit, a spring pin as shown in FIG. 2 may be used. The figure shows a large-diameter spring pin 1 that is pressed into a shaft hole.
2 and a small-diameter spring pin 13 press-fitted inside the pin
(This may be a normal solid pin).

FIG. 3 and FIG. 4 show examples of attachment of the illustrated excavating blade to the bucket bottom plate. In this manner, the holder 1 is fixed to the upper or lower surface of the bucket bottom plate 20 by welding or the like, and the excavation bit 6 is inserted and fitted into the holder, and the two are connected by a detachable shaft. 3 and 4
14 is a hardfacing overlay. Since the digging blade arranged at the radially outer end of the bucket cannot avoid rubbing against the wall surface of the digging hole, it is preferable that the digging blade be hardened and reinforced.

Although the example in which the digging blade is mounted on the bottom plate of the digging bucket has been described as an example, the digging blade of the present invention is also effective when mounted on the tip of a digging wing.

[0023]

As described above, according to the present invention, a wide extension projection is provided on the partition wall of the holder, and the excavation rotational force and the pressing force are received by the fitting portion of the extension projection with the bit side groove, and the bit tail is formed. Since no load is applied to the plate and the connecting shaft, it is not necessary to increase the size to prevent breakage, making it possible to reduce the size of the entire system. The use of detachable digging blades is also possible for high-output earth drills and reverse-circulation digging machines that have been forced to work, contributing to faster blade tip replacement, reduced replacement labor, and improved machine operation rates. it can.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of a cutting blade of the present invention.

FIG. 2 is a perspective view showing another example (spring pin) of the connecting shaft.

FIG. 3 is a perspective view showing an example of mounting a cutting blade.

FIG. 4 is a perspective view showing an example of mounting a cutting blade.

FIG. 5 (a): plan view in use state (b): side view in use state

FIG. 6 is a perspective view of a drilling blade using a conventional fitting structure.

FIG. 7 is a sectional view of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holder 2 Concave part 3 Partition wall 4 Front 5 Extension protrusion 6 Drilling bit 7 Tail plate 8 Groove 9 Shoulder part 10 Shaft hole 11 Bolt 12, 13 Spring pin

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) E21B 10/62 E02F 9/28 E21B 11/00

Claims (1)

(57) [Claims] 1. A holder fixed to a wing tip of an excavation wing or a bottom plate of an excavation bucket, and an excavation bit detachably attached to the holder. A bit mounting portion of the holder has a first concave portion opened to an upper surface and a front surface, and a lower surface. A cross-section having an H-shape comprising a second recess opening to the front and a partition remaining between the recesses, the partition having a widened extension projecting forward from the front of the holder; A tail plate that fits in the first and second recesses, a groove into which the partition fits, and a shoulder that abuts against the front surface of the holder. A digging blade for a construction machine having a hole, wherein the digging bit is inserted into the holder, fitted therein, and connected to the holder with a detachable shaft that passes through the shaft hole.