JPH0414568A - Reinforced concrete cutting excavation bit - Google Patents

Abstract

PURPOSE:To facilitate exchange work by mounting a cylinder body to the lower end of a rotary shaft, fitting a ring to the lower part of the cylinder body so that it is capable of loading and unloading, and mounting a plurality of excavation claws projected downward to the lower part of the ring. CONSTITUTION:A cylinder body 6 is so provided that it is fixed concentrically to the lower end of a cylindrical rotary shaft 2 rotated by a motor 1, and a ring 8 is fitted to the cylinder body 6 so that it is capable of loading and unloading. A plurality of screw holes 9 are bored in a fitting section 8a of the ring 8 in the circumferential direction, through-holes 10 are bored in the cylinder body 6, washers 11 are fitted to them, and the cylinder body 6 is connected to the ring 8 with bolts 12. After that, a notch 8d is provided to the lower part of the ring 8, and a claw mounting plate 15 provided with screw holes 14 is welded to the notch 8d to provide excavation claws 13. According to the constitution, mounting work can be easily carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an excavation bit for cutting out reinforced concrete constituting foundation ground, the bottom of a basement, and the like.

(Conventional technology) When demolishing an old reinforced concrete building and constructing a new one, the reinforced concrete ground or the bottom of the basement, etc., is excavated and removed using a rotary excavation bit, and a new reinforced concrete is constructed to replace the ground. Build etc. As shown in Fig. 6, an excavation bit for excavating such reinforced concrete ground, etc. has a link 3 attached to the lower end of a cylindrical rotating shaft 2 that is rotated by a drive motor l attached to an arm of a working machine. Welding (4 is the welding part),
A ring with a plurality of digging claws 5 attached to the lower end of the ring 3 has been used.

(Problem to be Solved by the Invention) However, according to the above-mentioned prior art, if the link 3 is damaged, the ring 3 must be cut off at the welded part 4 and a new link 3 must be welded. There was a problem that the replacement work was time-consuming and required skill.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to provide a drilling bit for cutting reinforced concrete that facilitates the replacement of rims and has an advantageous structure in terms of strength.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention includes a cylindrical body coaxially fixedly attached to the lower end of a rotating shaft.

It consists of a link that is removably fitted to the lower part of the cylindrical body, and a plurality of digging claws that are attached to the lower part of the link so as to protrude downward. A plurality of screw holes are arranged in the circumferential direction in the thing to be fitted, through holes corresponding to the screw holes are provided in the thing to be fitted on the outside, a washer is fitted in each of the through holes, and a washer is fitted in each of the through holes. The cylindrical body and the ring are coupled by loosely fitting a bolt into the washer, screwing it into the screw hole, and tightening it.

(Function) Since the excavation bit for reinforced concrete cutting of the present invention has the above-described structure, the excavation reaction force acting on the ring is generated between the washer belly surface and the outer surface of the link that comes into contact with it (if the ring is fitted inside). No digging reaction force is applied to the bolt because it is transmitted to the cylindrical body by the repulsive force or the frictional force between the washer belly surface and the outer surface of the cylindrical body that comes into contact with it (if a link is fitted externally). Furthermore, since the bolt is loosely fitted into the hooker, it is easy to attach and detach, and there is no need for fusing or welding to replace the link.

(Example) FIG. 1 is a side view showing an embodiment of a drilling device including a drilling bit for cutting reinforced concrete according to the present invention, FIG. 2 is an exploded perspective view showing a part of the drilling bit of the embodiment, and FIG. The figure is a horizontal sectional view showing the coupling structure between the cylindrical body and the link in this embodiment, FIG. 4 is a side view showing the structure of the attachment of the digging claw in this embodiment, and FIG. FIG.

Reference numeral 6 denotes a cylindrical body which is fixedly attached to the lower end of the cylindrical rotating shaft 2 rotated by the motor 1 by welding (7 indicates a welded part). Reference numeral 8 denotes a link that is detachably fitted into the cylindrical body 6. As shown in FIG. A stepped portion 8b is formed between the lower portion and the lower portion.

The fitting portion 8a of the link 8 has a plurality of screw holes 9 in the circumferential direction.
On the other hand, the cylindrical body 6 is provided with through holes 1O corresponding to the screw holes 9, respectively. Then, fit the fitting part 8a of the ring 8 into the cylindrical body 6 until it abuts the stepped part 8b or the lower surface of the cylindrical body 6, and as shown in FIGS. 2 and 3, the diameter of each through hole lO is adjusted. The cylindrical body 6 and the ring 8 are connected by fitting matching washers 11, loosely fitting a hexagonal socket head bolt 12 into each washer 11, and screwing it into the screw hole 9 and tightening it.

In this embodiment, a positioning block 8c is provided on the stepped portion 8b of the ring 8 in order to facilitate alignment between the screw hole 9 and the through hole lO when the cylindrical body 6 and the ring 8 are connected. On the other hand, the lower side of the cylindrical body 6 is provided with a notch 6a into which the positioning block 8c is fitted, and when the positioning block 8c is fitted into the notch 6a, it is automatically placed in the position of the through hole 10 or the screw hole 9. I try to match the target.

According to the structure of this installation, as shown in FIG. As a result, the force is transmitted to the cylindrical body 6 via the washer 11, so that the force is not applied to the bolt 12. Furthermore, even if there is some positional deviation between the screw hole 9 and the through hole 1o, the loose fitting structure between the bolt 12 and the washer 11 allows
Any misalignment will be absorbed and they will be joined together without any difficulty.

Further, even if there is some gap between the cylindrical body 6 and the link 8, the thickness of the washer 11 absorbs the gap, and the excavation reaction force is always transmitted through the washer 11. Also, the washer 11 of the bolt 12
Coupled with the loose fitting structure, high precision is not required in manufacturing the cylindrical body 6 and the ring 8, and in machining the screw hole 9 and the through hole 1O.

In this way, the ring 8 is removably fitted to the bolt 12.
With this structure, the work can be completed much more easily and quickly than the conventional work of cutting off the old ring and welding a new ring to replace it.

As shown in FIGS. 4 and 5, the structure for installing the digging claw 13 in this embodiment is as follows: an inclined notch 8d is provided at the bottom of the link 8, and a screw hole 14 is provided in the notch 8d. To attach the claw, the plate 15 is welded, and the four parts 13a provided on one side of the excavating claw 13 are fitted to the plate 15, and the bolt 16 is inserted into the through hole 13b provided in the excavating claw 13. The attachment is done by screwing into a screw hole 14 provided in the plate 15, thereby making it easier to replace the excavation claw 13 and to prevent the excavation reaction force from being applied to the bolt 16.

In addition, when attaching a new excavation pawl 13 to the notch 8d, a nut 17 is planted in the part facing the plate 15, and a bolt 18 for temporarily fixing the excavation pawl is screwed into the nut 17. When installing a new excavation pawl 13,
To attach the digging claw 13 to the plate, screw the bolt 18 deeply, fit the digging claw 13 to the plate 15, turn the bolt 1B back, and press the head of the bolt 18 to the digging claw 13. 15, and then attach the digging claw 13 with the bolt 13. As a result, when attaching the excavating claw 13, there is no need to hold the excavating claw 13 in hand at times, and the attachment becomes easy.

Note that, as shown in No. 47, the excavating claw 13 is rotated in the rotation direction (
By slanting the upper part of the digging claw 13 (inclination angle θ is less than 90 degrees, preferably 10 degrees to 45 degrees) with respect to the arrow B), the digging claw can be prevented from jumping up during excavation. 1. Smooth excavation is possible, and damage to the cutting edge is also prevented.

In the above embodiment, an example in which the cylindrical body 6 is fitted externally to the link 8 is shown, or a structure in which the cylindrical body 6 or the link 8 is fitted internally may be used. Changes or additions are possible.

(Effects of the Invention) According to the present invention, the ring to which the excavating claw is attached is removably fitted into the cylindrical body fixed to the rotating shaft and connected with bolts. Compared to replacing the ring by welding, the replacement work can be done more easily and in less time, and even non-experts can easily do it.

In addition, the excavation reaction force that acts on the link acts on the cylindrical body through the washer due to the frictional force between the washer and its contact surface, so it is not applied to the bolt, and there is no risk of bolt breakage. Even if there is some misalignment between the screw hole at the joint and the corresponding washer fitting hole, the loose fitting structure between the bolt and washer absorbs the misalignment and allows for smooth connection. can. Furthermore, even if there is a slight gap between the cylindrical body and the link, the thickness of the washer absorbs the gap, and the excavation reaction force is transmitted through the washer and transferred to the washer of the bolt. Coupled with the loose fit structure, high precision is not required in manufacturing the cylinder and links, and in machining screw holes and through holes.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of a drilling device including a drilling bit for cutting reinforced concrete according to the present invention, Fig. MS2 is an exploded perspective view showing a part of the drilling bit of the embodiment, and Fig. 3 is the embodiment. FIG. 4 is a side view showing the structure of the attachment of the excavating claw in this embodiment, FIG. 5 is a sectional view taken along line A-A in FIG. 4, and FIG. The figure is a side view showing an embodiment of a drilling device including a conventional drilling bit for cutting reinforced concrete. l: motor, 2: rotating shaft, 6: cylindrical body, 7. Welded part, 8
;Link, 9: Screw hole, 1O2 through hole, 1 washer,
12: Bolt, 13 = drilling claw, 15° claw mounting plate, 16
, :Boruto, 17:Natsuto 18:Boruto

Claims (1)

[Claims] a cylindrical body that is fixed and fixed concentrically to the lower end of the rotating shaft;
It consists of a ring that is removably fitted to the lower part of the cylindrical body, and a plurality of digging claws that are attached to the lower part of the ring so as to protrude downward. A plurality of screw holes are arranged in the circumferential direction in the thing to be fitted, through holes corresponding to the screw holes are provided in the thing to be fitted on the outside, a washer is fitted in each of the through holes, and a washer is fitted in each of the through holes. A drilling bit for cutting reinforced concrete, characterized in that the cylindrical body and the ring are connected by loosely fitting a bolt into the washer, screwing it into the screw hole, and tightening it.