JP2519781Y2 - Removable drilling blade - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detachable cutting blade suitable for a cutting head such as an earth auger of a rock drilling machine.

[0002]

2. Description of the Related Art As detachable excavating blades used for rock excavation, various constructions have been conventionally provided.
As an example thereof, one described in Japanese Utility Model Laid-Open No. 58-115592 is known.

As shown in FIG. 8, the detachable excavating blade 1 of the above-described example has a holder 3 fixed to the outer peripheral portion of a spiral earth auger (hereinafter abbreviated as auger) 2 and a holder 3. A cutter bit (hereinafter, abbreviated as a bit) 4 that is detachably attached, and is roughly configured. A blade portion 5 formed at the tip of the bit 4 is directed obliquely downward along the spiral direction of the auger 2. It is attached to the auger 2 and used for rock excavation. Here, in the detachable excavating blade 1 as described above, at the time of excavation, the blade portion 5 of the bit 4 has a resistance to rotation of the auger 2 and a resistance to axial feeding of the auger 2.
Since the types of resistance act strongly from different directions, it is necessary to firmly attach the bit 4 to the holder 3 and surely prevent the bit 4 from floating with respect to the holder 3.

Therefore, in the above-mentioned detachable excavating blade 1, as shown in FIG. 9, a pair of flanges 6 and 7 formed on the rear end side of the bit 4 sandwich the fitting convex portion 8 of the holder 3 to form a flange. The opposing wall surfaces 6a, 7a of 6, 7 and the side surfaces 8a, 8b of the fitting convex portion 8 are brought into close contact with each other, and the height direction one side surfaces 6b, 7b of the flanges 6, 7 are brought into close contact with the support wall portion 9 of the holder 3. Then, in this state, the bolt 10 inserted from the one flange 6 toward the fitting convex portion 8 is screwed into the other flange 7 and tightened to firmly connect the bit 4 to the holder 3.

Further, in order to supplement the connection by the bolt 10 and prevent the looseness of the bit 4 more reliably, the projections 11 and 1 are respectively provided on the end portions of the fitting projection 8 and the flanges 6 and 7.
2 and 13 are formed, and these are fitted into the groove portions 14, 15 and 16 of the bit 4 and the holder 3 to restrain the upward movement of the bit 4.

[0006]

By the way, according to the above-mentioned conventional detachable excavating blade 1, the free movement of the bit 4 in the holder width direction and the vertical direction is surely restrained, but the fitting portion as a whole is In many cases, in particular, the protrusions 11 to 13 and the grooves 14 to 16 are respectively provided on the holder 3 and the bit 4 in order to restrain the looseness of the bit 4 in the direction away from the holder supporting wall 9.
However, there is a drawback in that the number of processing steps is increased and the manufacturing cost is suppressed. The present invention has been made under such a background, and an object thereof is to provide a detachable excavating blade which can surely restrain the movement of the bit with respect to the holder and can be easily processed.

[0007]

In order to solve the above-mentioned problems, the present invention proposes a support wall portion of the holder on the side surface of the fitting convex portion formed on the holder, which is in close contact with the flange facing wall surface of the bit. The holder sloped portion is formed so as to gradually project outward in the holder width direction as it is separated from the fitting protrusion in the height direction, and the bit sloped portion that is in close contact with the holder sloped portion is formed on the opposing wall surface of the bit flange. It is a thing.
Here, the holder width direction is a direction orthogonal to the insertion direction of the bit into the holder and a direction in which side surfaces of the side surfaces of the fitting convex portion that are in close contact with the facing wall surface of the bit are arranged. Also,
The height direction of the holder means a direction orthogonal to both the bit insertion direction and the holder width direction.

[0008]

According to the above construction, the holder inclined portion projecting outward in the holder width direction and the bit inclined portion are brought into close contact with each other as they are separated from the supporting wall portion of the holder, so that they are separated from the supporting wall portion of the bit. Since the movement of the bit is restrained, it is not necessary to form a protrusion or a groove for restraining the movement of the bit in the direction away from the support wall portion in addition to the fitting convex portion of the holder and the fitting concave portion of the bit.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, a detachable excavating blade 20 of this embodiment is roughly composed of a holder 21 welded to an excavating head such as an auger and a bit 22 detachably attached to the holder 21 as in the conventional case. It is configured.

As shown in FIGS. 1 to 3, the holder 21 is a substantially rectangular parallelepiped base portion 23 to be welded to the auger described above, and the holder 21 is disposed at the center of the holder 21 in the width direction and the holder portion 21 is removed from the base portion 23. A fitting projection 24 protruding forward, and a rectangular flat plate-shaped support wall 25 provided on one end in the height direction of the fitting projection 24 and projecting outward in the holder width direction. Is. The fitting convex portion 24 has an upper surface 24a that is flush with the upper surface 23a of the base portion 23, and side surfaces 24b and 24c that extend from the upper surface 24a toward the inner surface 25a of the support wall portion 25.
And the side surfaces 24b and 24c are formed in an inclined surface shape that gradually protrudes outward in the holder width direction from the support wall portion 25 toward the upper surface 24a. As a result, each side surface 2
The entire surface of 4b and 24c is a holder inclined portion 26.
The side surfaces 24b and 24c are formed symmetrically with respect to both the width direction center line m1 of the holder 21 in a plan view (FIG. 1) and the width direction center line m2 of a front view (FIG. 3).

The inner surface 25a of the support wall portion 25 is formed into an inclined surface inclined in a direction orthogonal to the side surfaces 24b and 24c of the fitting projection 24, and the width of the holder 21 is the same as the side surfaces 24b and 24c. It is symmetrical with respect to the direction centerlines m1 and m2. Further, the outer surface 25b of the support wall portion 25 is
3 is flush with the lower surface 23b of the base 3, and the side surface 25c is a flat surface orthogonal to the outer surface 25b.
It is flush with 3c. The length of the support wall portion 25 in the holder front-rear direction is set to be slightly longer than that of the fitting convex portion 24. Thereby, the inner surface 25 of the support wall portion 25
“A” wraps around not only to the side of the fitting convex portion 24 but also to the tip side, and this portion is formed as a flat surface parallel to the outer surface 25b.

The fitting protrusion 24 has four portions extending in the holder width direction.
A bolt hole 27 of a book and a pin mounting hole 28 extending in the holder front-rear direction are formed, and both ends of the bolt hole 27 have side surfaces 24.
b and 24c, and the pin mounting hole 28 is opened in the tip end surface 24d of the fitting convex portion 24. The pin mounting hole 28 has a positioning pin 2 formed of a spring pin or the like.
9 is attached with its tip protruding.

As shown in FIGS. 1, 4, 5, and 6,
The bit 22 is provided with a tapered blade portion 30 on the front end side, and is formed with a pair of flanges 31 and 32 protruding rearward along both end edges of the bit 22 on the rear end side. Is. The flanges 31 and 32 are side surfaces 31 a, 31 b and 32 arranged in the height direction of the bit 22.
a, 32b, side surfaces 31c, 32c facing outward in the width direction of the bit 22, and a facing wall surface 31 facing the center side in the width direction.
d, 32d, and these opposing wall surfaces 31
A fitting concave portion 33 into which the fitting convex portion 24 of the holder 21 is inserted is defined between d and 32d.

Wall faces 31d, 3 facing each other of the flanges 31, 32
2d is formed in an inclined surface shape that recedes outward in the bit width direction from one side surface 31a, 32a aligned in the height direction toward the other side surface 31b, 32b. The inclination angle θ of these opposing wall surfaces 31d and 32d with respect to the bit height direction and the minimum width W between the opposing wall surfaces 31d and 32d are the inclination angle θ and the minimum width W of the fitting projection side surfaces 24b and 24c of the holder 21 (see FIG. 3)), so that the entire surfaces of the opposing wall surfaces 31d and 32d are held by the holder inclined portion 2
6 is a bit inclined portion 34 that can be closely attached. In addition,
The opposing wall surfaces 31d and 32d are formed symmetrically with respect to both the width direction center line m3 of the bit 22 in a plan view (FIG. 4) and the width direction center line m4 of a rear view (FIG. 5). Further, the side surface 31 of the flanges 31, 32 is
The a and 32a are formed in an inclined surface shape that is inclined in a direction orthogonal to the facing wall surfaces 31d and 32d.

Further, one of the flanges 31 and 32 is formed with four bolt mounting holes 35 extending in the bit width direction, and each of the side walls 31c has a bit mounting hole 35 formed therein, as shown in FIG. An elongated hole 35a extending in the front-rear direction of 22 is provided. On the other hand, on the other flange 32, four female screw holes 36 are formed coaxially with the bolt mounting hole 35.

Further, the bit 22 is formed with a fitting hole 37 extending along the widthwise center line m3, and the fitting hole 37 is opened in the bottom surface 38 of the fitting recess 33. An escape portion 39 is formed at the intersection of the bottom surface 38 and the opposing wall surfaces 31d and 32d, which is recessed in an arc shape toward the tip side of the bit 22.

In the holder 21 and the bit 22 configured as described above, the fitting convex portion 24 of the holder 21 and the fitting concave portion 33 of the bit 22 are fitted in the holder front-rear direction so that the holder inclined portion 26 and the bit inclined. The parts 34 come into close contact with each other, and in this state, the bolts 40 (see FIG. 1) are inserted into the bolt holes 27 from the bolt holes 35 and screwed into the female screw holes 36 to be tightly connected to each other. An example removable drilling blade 20 is configured. At this time, the positioning pin 29 of the holder 21 is fitted into the fitting hole 37 of the bit 22 to restrain the bit 22 from moving in the holder width direction.

According to the removable excavating blade 20 of this embodiment, however, the side surfaces 24b and 24c of the fitting convex portion 24 and the opposing wall surfaces 31d and 32d of the flanges 31 and 32, that is, the holder inclined portion 26 and the bit inclined portion. The close contact with 34 prevents the bit 22 from moving in the direction away from the holder support wall portion 25, thereby preventing the bit 22 from moving in the holder height direction. Therefore, in order to restrain the bit 22, it is not necessary to form a fitting portion such as a small protrusion or a groove in addition to the fitting projection 24 and the flanges 31 and 32, and the number of processing steps of the holder 21 and the bit 22 is reduced. .

In this embodiment, the holder inclined portion 26 is formed on the entire side surfaces 24b and 24c of the fitting convex portion 24.
Further, the bit inclined portion 34 is formed on the entire surface of the facing wall surfaces 31d, 32d of the flanges 31, 32, but the present invention is not limited to this, and the side surfaces 24b, 24c and the facing wall surface 3 are not limited to this.
The holder inclined portion 26 and the bit inclined portion 34 may be provided only on a part of 1d and 32d. Also, these holder inclined portions 2
6 and the bit inclined portion 34 do not need to be symmetrical with respect to the center lines m1 to m4, and it is sufficient that both are firmly attached.

[0020]

As described above, according to the detachable excavating blade of the present invention, the movement of the bit in the direction away from the supporting wall portion is restricted only by the contact between the inclined portion of the holder and the inclined portion of the bit. Therefore, it is not necessary to separately form a protrusion or groove for restraining the movement of the bit in addition to the fitting protrusion of the holder and the fitting recess of the bit. Therefore, it is possible to reduce the man-hours for processing the holder and the bit and reduce the manufacturing cost of the removable excavating blade.

[Brief description of drawings]

FIG. 1 is a plan view of a holder according to an embodiment of the present invention.

FIG. 2 is a view from the direction of the arrow II in FIG.

FIG. 3 is an arrow view from a direction III in FIG. 2;

FIG. 4 is a plan view of a bit forming the removable excavating blade of FIG. 1.

5 is a view from the direction V in FIG.

FIG. 6 is a view from the direction of arrow VI in FIG.

FIG. 7 is a view from the direction of the arrow VII in FIG.

FIG. 8 is a view showing a state in which a removable excavating blade is attached to an earth auger.

9A and 9B are views showing a conventional detachable excavating blade, where FIG. 9A is a side view and FIG. 9B is a plan view.

[Explanation of symbols]

 20 Detachable excavating blade 21 Holder 22 Cutter bit 24 Fitting convex part 24b, 24c Side surface of fitting convex part 25 Support wall part 26 Holder inclined part 30 Blade part 31, 32 Flange 31d, 32d Flange facing wall surface 33 Fitting concave part 34-bit inclined section

Claims (1)

(57) [Scope of utility model registration request] 1. A holder, the rear end of which is attached to an excavating head of an excavator, and a cutter bit, the front end of which is provided with a blade portion, wherein both edges of the cutter bit are provided at the rear end of the cutter bit. A pair of flanges projecting rearward along is formed, and in the holder, a fitting convex portion which enters a fitting concave portion defined between the flanges and a side surface of which is in close contact with an opposing wall surface of the flange, In the detachable excavating blade, which is formed with a support wall portion that protrudes outward in the width direction of the holder from one end side in the height direction of the fitting convex portion and contacts one side surface in the height direction of the pair of flanges, On the side surface of the fitting convex portion, a holder inclined portion that gradually protrudes outward in the holder width direction as being separated from the support wall portion in the height direction of the fitting convex portion is formed, and the pair of flanges On the opposite wall, Removable digging edge, characterized in that the formation of the bit inclined portion in close contact with the dust inclined portion.