JPH0644571Y2 - Cutting blade of bolt cutting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use of the Invention] The present invention relates to a cutting blade of a bolt cutting machine.

[Background of the invention]

In the construction of buildings and the like, there are cases where full screws are used when hanging lighting equipment, air conditioning equipment, etc. from the ceiling. Since this full screw has a fixed length, it is cut to an appropriate length at the construction site before use. FIG. 6 shows the state of shearing of the cutting blade 1 and the full screw (5) of the bolt cutting machine used for this cutting work. The cutting blade 1 is engraved with a full screw (5) to be cut and a female screw (2) having an equal pitch. The full screw (5), the cutting blade upper blade (1a), and the cutting blade lower blade ( 1b) is cut by shearing in the correct meshed condition as shown in the figure.

In the conventional cutting blade, as shown in FIG. 6, the cutting blade upper blade (1a) and the cutting blade lower blade (1b) were mounted with no clearance and no clearance. Therefore, the crack (6a) that the upper blade (1a) progresses at the time of cutting and the crack (6) that propagates from the lower blade (1b).
In the case of b), due to the property of inclining at an angle, it did not match in the vicinity of the center of the fracture surface 7, and sheared while causing a shift. Therefore, as shown in FIG. 7, a bump-shaped step (9) was formed on the fracture surface (7) of the full screw (5), and the nut could not be inserted into this portion in some cases. In addition, the force required for shearing was large, and the mechanism for moving the cutting blade (1) was also large and heavy.

Fig. 8 shows the cutting blade upper blade (1
This is the case where the cutting blade is separated so that there is an appropriate clearance between the cutting blade (1b) and the cutting blade (1b). In this case, the diagonally advancing crack (upper blade) (6a) and crack (lower blade) (6b) match at the center of the fracture surface 7, and the bump-shaped step 9 can be eliminated as shown in FIG. In addition, the cutting load is reduced, but a large burr 10 is formed in the sheared portion of the thread of the full screw, and the nut cannot be inserted in some cases.

[Purpose of device]

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to reduce burrs and bump-like steps that occur at the cutting portion, to smoothly insert the nut, to reduce the cutting load, and to reduce the size and weight of the bolt cutting machine. Especially.

[Outline of device]

The present invention is capable of obtaining a smooth fracture surface without bump-like steps by giving an appropriate clearance proportional to the thickness in the shearing direction, and also reducing the cutting load, and the screw threads on both sides of the full screw. Focusing on the fact that the cutting part can reduce the occurrence of burrs that obstruct nut insertion by eliminating clearance, cut so that the appropriate clearance can be obtained at the center part, side part, and thread part of the cutting blade. The shape of the blade is devised.

[Example of device]

Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 5 shows an electric bolt cutting machine. The rotation of the rotating shaft of the electric motor 18 is reduced by a plurality of gear trains built in the gear box 11, the crank 12 which is an output shaft is rotated, and an arm 13 is used. The cutter holder 14 is swung. Cutter holder
The cutting blade 1 of the present invention is fixed to each of the cutter holder 15 fixed to the gear box 11 and the gear box 11 by a mounting screw 19, and the entire screw 5 is cut by the cutting blade 1 by shearing.

In FIG. 1, a cutting blade 1 is engraved with a full thread 5 to be cut and an internal thread 2 having an equal pitch and a thickness of 3.
It is 5 times. Further, a circular arc groove 4 having a width of 8.5 mm and a depth of 0.5 mm, which is narrower than the root diameter of the female screw 2 (9 mm in the case of all M10 screws), is provided on the side surface of the cutting blade 1. Attaching to the cutter holder 14 and the cutter holder 15 is as shown in FIG.
With the side with and without the side facing each other, the full screw 5 and the cutting blade 1 are correctly engaged, and the cutting blade upper blade 1a
And the cutting blade lower blade 1b is set without clearance.

In Fig. 2, the thickest of all screws (5) (M10
At the central portion (10 mm with all screws) (on the line AA), the depth of the arc groove 4 is about 0.5 mm, and there is a clearance of about 5%. Also, the side cut part that is slightly laterally displaced (on the line BB)
Then, although the thickness of the full screw (5) becomes thin, the depth of the circular arc groove (4) also becomes small accordingly, so that an appropriate clearance can be maintained. Therefore, as shown in FIG. 3, a crack 6a and a crack 6b that obliquely progress from the cutting blade upper blade 1a and the cutting blade lower blade 1b.
Match in the vicinity of the center of all screws 5, and no bump-like step is formed on the fracture surface 7 as shown in FIG. Also, the thread cutting portion (C
At (-C line), the clearance is zero because it is out of the arcuate groove 4, and a large burr does not occur as shown in FIG.

[Effect of device]

As described above, according to the present invention, since a smooth fracture surface with small burrs or bump-like steps is obtained, the nut can be smoothly inserted into all the screws, and the user can make burrs or bump-like steps. It is safe without accidentally injuring your hands.

Also, by optimizing the clearance, it is possible to reduce the load required for shearing and reduce the size and weight of the bolt cutting machine.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a cutting blade for a bolt cutting machine according to the present invention, FIG. 2 is a plan view and a front view of the cutting blade, and FIG.
The figure is a sectional view showing the state of cutting all screws with the same cutting blade,
FIG. 4 is a perspective view showing a fractured surface of a full screw cut by the same cutting blade, FIG. 5 is a perspective view showing an appearance of a bolt cutting machine using the same cutting blade, and FIG. FIG. 7 is a cross-sectional view showing a state of cutting when lost, FIG.
It is a perspective view of the fracture surface obtained in the state of the figure. FIG. 8 is a cross-sectional view showing a state of cutting when a conventional cutting blade is provided with a clearance, and FIG. 9 is a perspective view of a fractured surface obtained thereby. In the figure, 1 is a cutting blade, 1a is a cutting blade upper blade, 1b is a cutting blade lower blade, 2 is an internal thread, 3 is a cutting blade mounting screw, 4 is an arc groove, 5
Is a full screw, 6a is a crack, 6b is a crack, 7 is a full screw fracture surface, 8 is a thread cutting portion, 9 is a bump-like step, 10 is a burr, 11
Is a gear box, 12 is a crank, 13 is an arm, 14 is a cutter holder, 15 is a cutter holder, 16 is a hanging hook, 17 is a handle, 18 is an electric motor, and 19 is a mounting screw.

Claims (1)

[Scope of utility model registration request] 1. A threaded surface having a shape divided in half by a center line having a pitch equal to that of the full thread is engraved on an inner peripheral surface of the full-threaded thread, etc., which is in contact with a bolt. In a bolt cutting machine that cuts the bolt with a pair of cutting blades that swing up and down, a side surface of the cutting blade is provided with an arc groove that is narrower than the root diameter of the threaded surface and has a deep center and shallow sides. A cutting blade of a bolt cutting machine characterized by that.