JPH0344428Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a two-step tap.

[Conventional technology]

For example, as shown in the side views of FIGS. 4 and 5, a relatively large-diameter screw is cut into one of two parallel members of the workpiece W, and a relatively large-diameter screw is cut coaxially with the other member. To carve a small-diameter screw, first, as a first step, a large-diameter screw is carved in one member using a large-diameter short tap, and then, as a second step, as shown in FIG. As shown in Figure 5,
It is common to cut small diameter threads with small diameter long shank taps.

[Problem that the invention attempts to solve]

However, with this method, it is necessary to change the taps between the large-diameter short tap and the small-diameter long tap on the drilling machine, which takes time.

The present invention was proposed in view of these circumstances, and provides an economical two-stage tap that can carve large-diameter screws and small-diameter screws in a short time using the same tap without replacing the tap. The purpose is to

[Means for solving problems]

To this end, the present invention consists of a small-diameter screw blade part that is machined into the same shank and cuts a relatively small-diameter screw, and a large-diameter screw blade part that is machined adjacent to this and cuts a relatively large-diameter screw. It is characterized in that the chip discharge grooves of the small diameter threaded portion and the large diameter threaded portion are provided in opposite directions.

[Function] With this configuration, it is possible to obtain an economical two-stage tap that can carve large-diameter screws and small-diameter screws in a short time with the same tap without replacing the tap.

〔Example〕

An embodiment of the present invention will be explained with reference to the drawings.
Figure 1 is a side view of the same, Figure 2 is a side view showing how to carve a large-diameter screw into a workpiece using the two-step tap in Figure 1, and Figure 3 shows how to carve a small-diameter screw into a workpiece in Figure 2. FIG.

First, in Fig. 1, 1 is a two-stage tap according to the present invention, and 2 is a small diameter threaded part machined over an appropriate length at the tip of the shank. A chip discharge groove 3 is carved in a direction slightly inclined with respect to the axis so that chips are discharged to the outside.

Reference numeral 4 denotes a large-diameter screw blade portion machined over an appropriate length between the small-diameter screw blade portion 2 and the shank 6, and the large-diameter screw blade portion 4 has an axis line so that chips can be discharged to the outside of the workpiece. A chip discharge groove 5 is formed which is inclined in a direction slightly inclined to that of the chip discharge groove 3, that is, in a direction opposite to the direction of inclination of the chip discharge groove 3.

In order to coaxially carve large-diameter screws and small-diameter screws on a workpiece as shown in Figs. 4 and 5 using such a two-stage tap, a large-diameter pilot hole must be made in the right side member of the workpiece W. After coaxially drilling a small diameter pilot hole in the left side member, first, as shown in FIG.
Next, as shown in FIG. 3, the double tap 1 is moved forward, and the small diameter screw blade portion 2 of the double tap 1 is used to cut a small diameter screw into the small diameter pilot hole.

Then, when carving a large diameter thread, the chips are discharged to the right of the workpiece along the chip discharge groove 5 of the large diameter screw blade part 4, as shown in Fig. When the engraving is completed, as shown in Fig. 3, the small-diameter screw is carved, and at this time, the chips are discharged to the left of the workpiece along the chip discharge groove 3 of the small-diameter screw blade part 2. Ru.

Therefore, the engraving of large diameter threads and small diameter threads can be carried out virtually continuously without changing the tap, and the cutting chips are automatically discharged outside the workpiece, so that there is no chipping inside the workpiece. Since there is no accumulation, there is no need to clean the workpiece.

Note that the direction of both chip discharge grooves can be optimally selected depending on the shape of the workpiece.

[Effect of idea]

According to such a structure, the following effects can be achieved.

(1) Large and small threads can be cut using the same tap without changing taps.

(2) When machining large and small screw holes on the same axis, chips can be automatically discharged to the outside of the workpiece.

(3) Since there is no need to replace taps, work time can be greatly reduced.

[Effect of idea]

In short, according to the present invention, the small-diameter screw blade part is machined into the same shank and cuts a relatively small-diameter screw, and the large-diameter screw blade part is machined adjacent to the small-diameter screw blade part and cuts a relatively large-diameter screw, By providing the chip discharge grooves of the small diameter thread part and the large diameter thread part in opposite directions, it is possible to carve large and small diameter threads with the same tap in a short time without having to change taps. Since an economical two-stage tap is obtained, the present invention is extremely useful in industry.

[Brief explanation of drawings]

Fig. 1 is a side view showing an embodiment of the two-stage tap of the present invention, Fig. 2 is a side view showing how to carve a large-diameter screw into a workpiece using the two-stage tap of Fig. 1, and Fig. FIG. 2 is a side view showing the procedure for carving a small-diameter screw on a workpiece; FIG. FIGS. 4 and 5 are side views showing the procedure for carving known large-diameter screws and small-diameter screws, respectively. 1...Two-stage tap, 2...Small diameter screw blade part, 3...
...Chip discharge groove, 4...Large diameter screw blade section, 5...Chip discharge groove, 6...Shank, 7...Chip, C...Chick, W...Work.

Claims (1)

[Scope of utility model registration request] It consists of a small-diameter screw blade part that is machined into the same shank and cuts a relatively small-diameter screw, and a large-diameter screw blade part that is machined adjacent to this and cuts a relatively large-diameter screw, and the small-diameter screw part and the large-diameter screw blade part are machined adjacent to each other and cut a relatively large-diameter screw. A two-stage tap characterized by having chip discharge grooves in the diametrical thread section in opposite directions.