JPS596971Y2 - branch pipe drilling machine drill - Google Patents

Description

[Detailed description of the invention] This invention involves drilling a branch hole in a water main etc. through a cock-type or ball-valve saddle distribution faucet, the diameter of which is relatively smaller than the inner diameter of the aforementioned distribution faucet. This invention relates to an improvement of a flat-spindle drill that allows the branch hole to be drilled at the center of the faucet at all times.

Conventionally, in order to prevent the drill from swinging forward, it has been customary to use a drill whose diameter is approximately the same as the inner diameter of the upright hole of the water faucet through which the drill passes.

In recent years, in order to prevent rust from forming on the cut surface of the branched hole, a method of fitting a sleeve around the hole has become widely adopted, and as a result, the actual diameter of the hole is As a result of the need to make the drill hole sufficiently smaller than the inner diameter of the upright hole of the water faucet that it passes through, the drill became small in diameter, and its tip deflection made it difficult to accurately hold the center of the drill hole.

In order to solve this problem, the present applicant provided a concave groove around the base of the drill, and by using the concave groove to loosely position a ring inscribed in the upright hole of the water faucet, the tip of the drill was He developed a flat-spindle drill that keeps the ring in the center of the water faucet, and filed an application for utility model registration (Utility Model Application No. 123389/1989). The groove narrowed the shaft diameter of the drill, lowering its strength, and required a great deal of effort in machining the drill, which was unreasonable.

In view of these circumstances, the inventor of the present invention has conducted various experiments and found that by increasing the contact pressure between the drill and the link higher than the contact pressure with the inner surface of the upright hole on the outer periphery of the link, the ring can be easily removed even if the conventional groove is omitted. The present invention aims to provide a drill for drilling machines that does not require any processing effort or decrease in shaft strength.

Hereinafter, the structure of the present invention will be explained in more detail based on one embodiment. 1 is an existing water main, 2 is a saddle band pre-installed on the branch of the main pipe, and 3 is a stand on the saddle band 2. 4 indicates the lower end of a perforator connected to the upper end of the upright hole 3' of the water distribution faucet 3, and 5 indicates a hole that penetrates through the water distribution faucet body. This is a drill for a drilling machine equipped with a drill.

On the other hand, 6 is a ring made of relatively hard rubber or plastic, which connects the chisel blade 5a and shaft 5b of the drill 5.
The contact pressure between the outer periphery of the link and the inner surface of the upright hole is kept smaller than the contact pressure between the inner hole and the periphery of the shaft.

Note that 7 in the figure indicates a branch hole drilled by the drill 5.

In the drill of the present drilling machine according to the above structure, the contact pressure between the inner hole of the ring 6 and the drill 5 is higher than the contact pressure between the outer periphery of the ring and the inner surface of the upright hole. The ring 6 also descends within the upright hole.

Therefore, the ring 6 sufficiently prevents the drill 5 from swinging out, and the chisel blade 5a can always be held at the center of drilling the upright hole 3'.

Therefore, when drilling the above-mentioned branch hole, the above-mentioned nongloss 6
At least until the tip of the chisel blade 5a reaches the correct drilling position on the main pipe, the chisel blade 5a remains in the upright hole to prevent its tip from wobbling, and from this point on, the chisel blade 5a is lowered. As drilling progresses, the ring 6 slips out from the lower end of the upright hole, and when the back of the chisel blade passes through a branched hole drilled, it is caught around the hole and remains on the shaft.
Only the drill 5 can then continue its descent and penetrate the complete branch hole 7.

(See Fig. 2) When attaching the ring 6 to the drill 5, either insert it from above the drill 5, or use a half ring in advance and attach it to the shaft 5b of the drill 5. Any method can be used depending on the shape of the drill, such as covering the hole with the base and integrating it as appropriate.As mentioned above, even if the drill of the present drilling machine is a small diameter drill, its axial strength will be reduced. Moreover, it prevents the tip of the chisel from swinging out during drilling, and allows drilling at an accurate position while keeping the tip of the chisel always above the center of the upright hole.
It is particularly useful as a drill for installing branch pipes that require anti-rust sleeves.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing the drill according to the present invention in a state immediately before drilling, and FIG. 2 is a partial sectional view showing the state of the drill after drilling is completed. In the diagram, 1...Water main, 2...Saddle band, 3...Water faucet body, 4...
Perforator, 5...Drill, 6...Ring.

Claims (1)

[Scope of utility model registration request] In a flat-weight type drill of a drilling machine for drilling a branch hole smaller in diameter than the upright hole of the above-mentioned water supply pipe in a water main etc. through a saddle water supply faucet, the chisel blade of the above-mentioned drill is made to have a diameter smaller than the upright hole, A hard ring made of rubber or plastic is fitted into the stepped part formed by the back surface of the chisel blade and its shaft, and the inner hole of the ring is pressed against the outer periphery and the inner surface of the upright hole, rather than the contact pressure against the shaft periphery of the drill. A branch pipe drilling machine drill characterized by a lower contact pressure with the branch pipe.