JPS6021122Y2 - Core drill with a mechanism to prevent cut-out waste boards from falling - Google Patents

Description

[Detailed explanation of the invention] This invention is mainly used for large-diameter drilling operations such as iron plates and synthetic resin plates, in which the cut-out waste plate after drilling is locked to the center drill of the core drill to prevent it from falling downward. This invention relates to an improvement of a core drill with a fall prevention mechanism.

Conventionally, core drills with a mechanism to prevent cut-out waste boards from falling have been developed, but these usually have an annular groove 7 with a U-shaped cross section as shown in FIG.
A stopper ring 10 with both ends open is loosely inserted into this annular groove, and the cut-out waste plate C is held in place by the stopper ring 10, but in this case, it is difficult to pull out the cut-out waste plate C from the center drill 4, which is extremely difficult. It was difficult to use.

This is because the annular groove has a U-shaped cross section, so it requires a fairly strong force to push the stopper ring sideways and into the groove. Because the groove is located just below the tip of the cutting blade on the body, it is difficult to grasp the cut-out waste board,
This is because the center drill usually does not drill at right angles to the plate, but instead passes through the plate at an angle, making it difficult to remove the cut-out waste plate.

This idea was devised in view of the above points, and it reliably prevents the cut-out waste board from falling after drilling, and also improves ease of use by making it easier to remove the cut-out waste board from the center drill. Furthermore, it is an object of the present invention to provide a core drill with a fall prevention mechanism that allows the stopper ring to smoothly penetrate into the groove during drilling.

Hereinafter, embodiments of the present invention will be described based on the drawings.

In FIGS. 1 to 4, a cylindrical body 1 for drilling is provided with a shank 2 at the top and a plurality of cutting blades 3 at the lower peripheral edge. A center drill 4 having a drilling blade 5 is attached to the part.

Further, an insertion hole 6 for extruding the cut-out waste plate C is provided on the upper surface of the cylindrical body 1 for perforation.

Then, an annular groove 7 is formed at a position slightly below the tip of the cutting blade 3 of the center drill 4, and the upper and lower walls of this annular groove 7 have tapered surfaces 8 and 9, respectively, which are inclined at about 45 degrees with respect to the horizontal line. , Continuing from this, stopper ring 10 described later
It is formed from concave surfaces 8' and 9' each having a semicircular cross section corresponding to the concave surfaces 8' and 9'.

In addition, in this annular groove 7, an elastic stopper ring 10 having a circular cross section with both ends open is attached to the center drill 4.
A part protrudes outward from the peripheral wall, and when subjected to external pressure, the annular groove 7
Attach it so that it goes inside.

FIG. 5 shows another embodiment, in which the stopper ring 10 has a triangular cross section, and similarly, the upper and lower walls of the annular groove 7 are tapered surfaces 8 along the ridgeline surface of the stopper ring 10, respectively. It is formed from 9.

Next, the operating mode of the core drill of the above embodiment will be explained.

As shown in Fig. 3, when the drilling blade 5 of the center drill 4 is brought into contact with the center of the drilling position of the plate body A and pressed, and the electric motor (not shown) connected to the shank 2 is rotated, the leading A center hole B is drilled in the plate body A using a center drill 4.

When the core drill is further pressed against the plate A, the stopper ring 1 partially protrudes from the peripheral wall of the center drill.
0 receives external pressure from the center hole B wall, contacts the upper tapered surface 8 in the annular groove 7, is guided deep into the groove along the tapered surface 8, infiltrates, and at the same time as the center hole B wall passes through. , protrudes outward from the stopper ring 10 due to its elasticity.

In parallel with this, a large-diameter hole is drilled in the plate A by the cutting blade 3 of the subsequent drilling cylinder 1, and after drilling, the disc-shaped cut-out waste plate C is stopped by a stopper ring 10 to prevent it from falling. Ru.

After that, a cylindrical body 1 for drilling with a waste plate C cut out from the plate A
and pull out the center drill 4.

Here, when the cut-out waste plate C is pulled out downward along the center drill 4, the stopper ring 10 receives external pressure from the wall of the center hole B of the plate body A, and the lower tapered surface of the annular groove 7 The cut-out waste plate C can be easily taken out from the center drill 4 because it is guided along the tapered surface 9 and smoothly sneaks into the groove.

Note that the position of the annular groove 7 of the center drill 4, in other words, the position of the stopper ring 10, is the cutting edge 3 of the boring cylinder 1.
It is provided close to the tip, so the cutout waste board C
If it is difficult to grasp, push out the cut-out waste board C from the extrusion insertion hole 6 of the cut-out waste board with a push rod or the like and take it out.

As explained above, the core drill with a fall prevention mechanism for cut-out waste boards of this invention has a stopper ring 10 for locking the cut-out waste boards C.
In order to mount the annular groove 7 in the center drill 10, the upper and lower walls of the groove are respectively inwardly expanded with tapered surfaces 8,
9, so that the stopper ring 10 that receives external pressure comes into contact with the tapered surface and is guided to infiltrate, so compared to the conventional annular groove with a U-shaped cross section, it is easier to cut out the scrap board after drilling is completed. C can be taken out very easily, improving work efficiency, and the stopper ring 10 can be smoothly inserted into the annular groove 7 during drilling, making it extremely easy to use.

[Brief explanation of drawings]

FIG. 1 is an overall front view of a core drill showing an embodiment of the present invention. FIG. 2 is a plan view of FIG. 1. FIG. 3 is a longitudinal sectional view showing the drilling state. FIG. 4 is an enlarged longitudinal sectional view of the main part. FIG. 5 is an enlarged vertical cross-sectional view of a main part showing another embodiment. FIG. 6 is an enlarged longitudinal cross-sectional view of the main parts of a conventional cutout waste plate fall prevention mechanism. 1... Cylindrical body for drilling, 2... Shank, 3... Cutting blade, 4... Center drill, 5... Drilling blade , 6... Insertion hole for extruding cut out waste board, 7... Annular groove, 8.9...
・Tapered surface, 8'9'...concave surface, 10・
... Stopper ring, A ... Plate body, B
... Center hole, C ... Cutting waste board.

Claims (2)

[Scope of utility model registration request] (1) A center drill 4 that protrudes downward from the tip of the cutting blades 3 is attached to the center of the cylindrical body 1 for drilling, which has a shank 2 on the upper side and a plurality of cutting blades 3 on the lower peripheral edge. , an annular groove 7 is located below the tip of the cutting blade 3 of the center drill 4.
In the core drill, an elastic stopper ring 10 with both ends open, which partially protrudes outward from the peripheral wall of the center drill 4 under normal conditions and completely sinks into the annular groove 7 under external pressure, is loosely inserted into the annular groove 7, The cut-out waste is characterized in that a stopper ring 10 subjected to external pressure is brought into contact with the upper wall and lower wall of the annular groove 7, respectively, and a light is formed on the inwardly expanding tapered surfaces 8 and 9 where the stopper ring 10 is guided to penetrate. Core drill with a mechanism to prevent plates from falling. (2) The core drill according to claim 1, wherein the cylindrical body 1 for drilling has an insertion hole 6 for extruding the cut waste plate on its upper surface.