JP2017132001A - Workpiece breaking method and tip tool for impact tool used for workpiece breaking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a workpiece breaking method capable of breaking a workpiece by shortening work time without needing a great impact force, and a top tool for an impact tool used for the workpiece breaking method.SOLUTION: The tip part 15 of a tip tool 10 is provided with four planes 21, 21, 21, and 21 arranged around the axis of the tip tool 10. A pair of entry blade parts 25 and 25 is formed by a pair of boundary parts in which an angle between the adjacent planes 21 and 21 becomes sharp, and a pair of expanded open parts 27 and 27 is formed by a pair of boundary parts in which the angle becomes dull. The entry blade parts 25 and 25 are only pressed to the open edge 52 of a hole 51 formed in a round bar 50 which is a workpiece to be broken, and then the expanded open parts 27 and 27 are pressed to the open edge 52 by applying an impact force to break the round bar 50.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a workpiece breaking method and a tip for an impact tool used in the workpiece breaking method.

  For example, Patent Literature 1 discloses an impact tool including an impact tool main body and a tip tool (chisel) that is pushed forward from the impact tool main body. Furthermore, the tip shape of the tip is a flat shape that can easily peel the coating film.

JP 2013-217048 A

  However, the tip shape of the tip disclosed in Patent Document 1 is suitable for the coating film peeling operation, but the shaft portion of the bolt in use or the nut in use can be broken. It was unsuitable to do.

  Here, when a workpiece such as a bolt or nut as described above is broken, a configuration in which the tip shape of the tip is made a sharper blade shape or the tip shape is a pointed shape can be proposed. However, when the tip shape of the tip tool is simply a sharp blade shape, a cutting groove is simply formed in the workpiece, and it takes time to completely break the shaft portion of the bolt, for example. was there. In addition, when the tip shape of the tip tool is simply a pointed shape, a deep concave portion is only formed, and for example, a large impact force is required to break the shaft portion of the bolt, There were problems such as taking time.

  Therefore, an object of the present invention is to provide a work breaking method that can shorten the work time and break the work without requiring a large impact force.

  Another object of the present invention is to provide a tip for an impact tool used in the work breaking method.

  The present invention is a workpiece breaking method including a breaking step of breaking a workpiece to be broken by an impact force of an impact tool, wherein the impact tool is pressed against an opening edge of a hole formed in the workpiece. The tip of the tip is tapered along the axial direction of the tip, and the shape of the cross section perpendicular to the axis at the tip is rhombus And the outer peripheral surface of the tip portion is composed of four plane portions arranged around the axis of the axis, and a pair of boundaries where an angle formed by adjacent plane portions among the plane portions is an acute angle. A pair of entering blade portions are formed by the portion, and a pair of expanded portions are formed by a pair of boundary portions where the angle becomes an obtuse angle. In the breaking step, first, the depth direction of the drilling and the axis of the tip Almost one direction Then, only the pair of blades are pressed against the opening edge of the perforation, an impact force is applied to the workpiece to allow the tip to enter the drill, and then the tip is moved. The workpiece breaking method is characterized in that the workpiece is broken from the periphery of the opening edge by pressing the expanded portion against the opening edge while entering the hole.

  In such a configuration, the distal end portion of the distal end tool is provided with an entering blade portion having a function of cutting the opening edge of the perforation and an expanding portion having a function of expanding and expanding the opening edge. Yes. That is, first, only the pair of entering blade portions is pressed against the opening edge of the perforation, and an impact force is applied to cut a part of the opening edge along the depth direction of the perforation with the entering blade portion. I will do it. Then, when the tip tool further enters into the perforation, the expanded portion also comes into contact with the opening edge, and in the process of the tip tool entering the perforation, the spread portion is in the perforation. The opening edge of the hole is expanded in the hole diameter direction of the perforation. Then, the peripheral portion of the perforation is pushed and spread while being cut by the tip portion of the tip tool, and the peripheral portion of the perforation is efficiently broken and the workpiece is broken from the periphery of the opening edge.

  Further, there is a perforation forming process for forming a perforation in a work to be broken, and in the breaking process, a configuration is proposed in which the tip of the tip is pressed against the opening edge of the perforation formed in the perforation forming process Is done.

  By adopting such a configuration, it is possible to appropriately execute the breaking process after forming a perforation that presses the distal end portion of the tip tool even when a perforation is not formed in the workpiece.

  Moreover, this invention is the tip tool for impact tools used for the said workpiece | work fracture | rupture method.

  By using such a tip, the workpiece can be easily and quickly broken.

  The work breaking method of the present invention has an effect that the work can be broken by reducing the working time without requiring a large impact force.

  Moreover, the tip tool for impact tools used in the work breaking method of the present invention has an effect that the work can be easily and quickly broken.

It is a schematic diagram which shows the impact tool provided with the tip implement which concerns on Example 1. FIG. The tip implement which concerns on Example 1 is shown, (a) is a partial expanded front view, (b) is a partial expanded right view, (c) is the sectional view on the AA line of (b). It is a figure which shows the round bar in the fracture | rupture process which concerns on Example 1, (a) is a fragmentary sectional top view, (b) is the BB sectional drawing of (a), (c) is ( It is CC sectional view taken on the line of a). The round bar in the fracture | rupture process which concerns on Example 1 is shown, (a) is a fragmentary sectional top view, (b) is the DD sectional view taken on the line (a), (c) is (a). It is EE sectional view taken on the line. The round bar in the fracture | rupture process which concerns on Example 1 is shown, (a) is a fragmentary sectional top view, (b) is a top view of the fracture | ruptured round bar. The nut in the fracture | rupture process which concerns on Example 2 is shown, (a) is a fragmentary sectional top view, (b) is a top view. The workpiece | work in the fracture | rupture process which concerns on Example 3 is shown, (a) is a fragmentary sectional top view, (b) is a top view which shows the state fractured | ruptured.

  Hereinafter, the example which actualized this invention is demonstrated in detail. In addition, this invention is not limited to the example shown below, A design change is possible suitably.

[Example 1]
As shown in FIG. 1, an impact tool 1 such as an air hammer tool is equipped with a tip tool 10 for impact tool (hereinafter simply referred to as a tip tool 10). The tip tool 10 includes a base end portion 11 to be inserted into the impact tool 1, a flange portion 12 having a diameter larger than that of the base end portion 11, and a tip end disposed on the front end side of the flange portion 12. A main body portion 13 having a portion 15. In addition, since the structure for detachably fixing the tip tool 10 to the impact tool 1 is a well-known technique, detailed description is abbreviate | omitted.

Next, the main part of the present invention is described.
As shown in FIG. 2, the tip portion 15 of the tip tool 10 has a tapered shape along the axial direction of the tip tool 10. And the shape of the cross section orthogonal to the said axis line in the front-end | tip part 15 is a rhombus shape.

  More specifically, the outer peripheral surface of the distal end portion 15 is composed of four plane portions 21, 21, 21, 21 arranged around the axis of the axis, and the four plane portions 21, 21, 21 described above. , 21, a pair of entering edge portions 25, 25 are constituted by a pair of boundary portions (ridge lines) in which the angle formed by the adjacent flat portions 21, 21 is an acute angle. On the other hand, a pair of expansion parts 27 and 27 are comprised by a pair of boundary part (ridgeline) from which the angle which the adjacent plane parts 21 and 21 make becomes an obtuse angle.

  Further, a tip 30 is formed on the distal end side of the flat portions 21, 21, 21, 21 so as to be further tapered than the flat portions 21, 21, 21, 21.

  Next, a process of breaking the metal round bar 50 as a work to be broken using the tip tool 10 will be described in detail with reference to FIG.

  First, the perforation 51 is formed in the round bar 50 (refer FIG. 3) (perforation process). Specifically, the depth direction of the perforation 51 is set to a direction orthogonal to the axis of the round bar 50. Further, the inner diameter of the perforation 51 is at least smaller than the outer diameter of the rear end portion of the distal end portion 15 of the distal end tool 10. The perforations 51 are not necessarily formed in a penetrating shape, but are formed to such a depth that a blade portion 25 and an expanded portion 27 described later can simultaneously contact the opening edge 52.

  Next, as shown in FIG. 3, the depth direction of the perforation 51 formed in the round bar 50 and the axial direction of the tip tool 10 are substantially matched, and only a pair of entering blade portions 25, 25 are perforated. Press against the opening edge 52 of 51. At this time, the pair of expanded portions 27 and 27 do not contact the opening edge 52 of the perforation 51.

  Here, since the distal end portion 15 of the distal end tool 10 has a rhombic cross-sectional shape, the diagonal length between the entering blade portions 25 and 25 corresponding to the acute angle portion is the expanded portion 27 corresponding to the obtuse angle portion. It becomes longer than the diagonal length between 27. For this reason, as shown in FIG. 3, only the entering blade portions 25, 25 are in contact with the opening edge 52 of the perforation 51, and the expanded portions 27, 27 are not in contact with the opening edge 52.

  Further, when the front end portion 15 is pressed against the opening edge 52 of the perforation 51, the axis of the round bar 50 and the same virtual plane including the pair of entering blade portions 25, 25 are set to be substantially perpendicular. In other words, the tip 10 is positioned at the opening edge 52 of the perforation 51 so that the pair of blade portions 25 and 25 are arranged along the direction in which the round bar 50 is to be broken.

  Then, the impact tool 1 is operated, and the impact tool 1 repeatedly applies an impact force to the tip tool 10. Then, at the tip portion 15, only the entering blade portions 25, 25 are in contact with the opening edge 52 of the perforation 51, so that the impact force is concentrated on the entering blade portions 25, 25. Accordingly, the cutting edges 25 and 25 cut into the round bar 50 while cutting the opening edge 52, and the tip tool 10 enters the perforation 51.

  Further, when the tip tool 10 enters the perforation 51 while applying an impact force as it is, the expanded portions 27 and 27 of the tip tool 10 are also pressed against the opening edge 52 as shown in FIG.

  When the tip 10 is further advanced into the perforation 51 as it is, as shown in FIG. 5, the expanded portions 27 and 27 spread the peripheral portion of the opening edge 52, and finally the round bar 50 is moved. Break to tear.

  More specifically, in the breaking step of the present embodiment, first, the opening edge 52 of the perforation 51 of the round bar 50 is partially cut by the entering blade portions 25, 25. At this time, since the impact force generated by the impact tool 1 is concentrated only on the entering blade portions 25 and 25, the impact force is difficult to disperse, and the tip tool 10 can be efficiently press-fitted into the perforation 51.

  Further, when the tip 10 further enters the perforation 51, a cutting portion formed by the entering blade portion 25 is formed, and at the same time, the expanding portions 27 and 27 expand the inner diameter of the perforation 51. As a result, the round bar 50 is broken and broken at the periphery of the perforation 51.

  The work to be broken is not limited to the round bar 50, but may be a bolt in use in a tightened state. In particular, when breaking a bolt that is in a tightened state at a site where the work hours of workers are limited, such as at a work site such as a damaged nuclear reactor building, With the shaft portion of the bolt exposed, the perforation is formed in the shaft portion, the shaft portion is broken by the above-described method based on the perforation, and the tightened state can be released in a short time. Is preferred.

[Example 2]
As in this embodiment, for example, of bolts and nuts used for connecting bridges or the like, the nut can be used as the workpiece of the present invention, and the tightened state can be released by breaking the nut.

  As shown in FIG. 6A, first, a perforation 81 is formed at the boundary between the bolt 70 and the nut 80 (perforation forming step). The depth direction of the perforation 81 is the axial direction of the bolt 70.

  Next, the depth direction of the perforation 81 and the axial direction of the tip tool 10 are substantially matched, and only the pair of entering blade portions 25, 25 are pressed against the opening edge 82 of the perforation 81. Then, the impact tool 1 is operated, and the tip tool 10 is caused to enter the perforation 81 while cutting the opening edge 82 in the depth direction of the perforation 81 by the entering blade portions 25 and 25.

  As the tip tool 10 is advanced into the perforation 81, the expanded portions 27 and 27 are also pressed against the opening edge 82, and the impact tool 1 is continuously operated as shown in FIG. 6B. Further, the nut 80 can be broken at the periphery of the opening edge 82.

Example 3
In addition, a configuration for breaking a burr of a workpiece obtained by casting, for example, is also proposed.

  As shown in FIG. 7A, a plurality of perforations 91 are formed at predetermined intervals on a planned fracture line 95 set on the workpiece 90.

  Next, the impact tool 1 is operated in a state in which the depth direction of the perforation 91 and the axial direction of the tip tool 10 are substantially matched and only the pair of entering blade portions 25 and 25 are pressed against the opening edge 92 of the perforation 91. Then, the tip tool 10 is caused to enter the perforation 91 while cutting the opening edge 92 with the entering blade portions 25, 25.

  At this time, the tip portion 10 is pressed against the opening edge 92 of the perforation 91 so that the direction of the pair of blade portions 25, 25 coincides with the direction of the planned fracture line 95.

  Further, when the tip tool 10 is advanced into the perforation 91 while applying an impact force, the expanded portions 27 and 27 of the tip tool 10 are also pressed against the opening edge 92 of the perforation 91, and the impact force is continuously applied. By so doing, as shown in FIG. 7B, so-called burrs can be removed by causing cracks from the peripheral portion of the opening edge 92 along the planned fracture line 95 and continuing the adjacent perforations 91 together. it can.

  In addition to the embodiments described above, the dimensions and the like of each part in the tip tool 10 can be freely selected as appropriate. For example, the shape of the tip tool 10 is not limited to the shape described above. Further, the flat portion 21 does not need to be a strict flat surface and may be slightly curved, but it is desirable that the entering blade portions 25 and 25 and the widened portions 27 and 27 are formed in a straight line. The tip 30 is not essential, and the tip shape of the tip 15 may be a planar shape perpendicular to the axis of the tip 10. Further, when only the pair of entering blade portions 25, 25 are pressed against the opening edges 52, 82, 92 of the perforations 51, 81, 91, the depth direction of the perforations 51, 81, 91 and the axial direction of the tip tool 10 Are substantially coincident with each other, but it is not necessary to exactly coincide with each other, and it is sufficient that they are coincident with each other so that the tip tool 10 can enter the perforations 51, 81, 91. Further, when the perforation is previously formed in the work to be broken, the perforation forming step may be omitted. Moreover, the workpiece | work used as a fracture | rupture object is not limited to metal materials, For example, a concrete block etc. may be sufficient.

DESCRIPTION OF SYMBOLS 1 Impact tool 10 Tip tool 15 Tip part 21 Plane part 25 Entering blade part 27 Expanding part 50 Round bar (workpiece)
51 Perforation 52 Opening edge 80 Nut (workpiece)
81 Drilling 82 Opening edge 90 Workpiece 91 Drilling 92 Opening edge

Claims (3)

A workpiece breaking method including a breaking step of breaking a workpiece to be broken by an impact force of an impact tool,
The impact tool is provided with a tip having a tip that is pressed against an opening edge of a drill hole formed in the workpiece, and the tip of the tip is tapered along the axial direction of the tip The shape of the cross section perpendicular to the axis at the tip is a rhombus, and the outer peripheral surface of the tip is composed of four flat portions arranged around the axis of the axis. In addition, a pair of entering blade portions are constituted by a pair of boundary portions where an angle formed by adjacent flat portions among the plane portions is an acute angle, and a pair of widened portions is constituted by a pair of boundary portions where the angle is an obtuse angle Has been
In the breaking step,
First, the depth direction of the drilling and the axial direction of the tip are substantially coincided, and only the pair of entering blades are pressed against the opening edge of the drilling, and an impact force is applied to the workpiece to apply the tip. Let the tool enter the hole,
Next, the work breaking method characterized by breaking the workpiece from the periphery of the opening edge by pressing the expanding portion against the opening edge while the tip tool is inserted into the perforation. Having a perforation forming process for forming perforations in the workpiece to be broken;
The work breaking method according to claim 1, wherein, in the breaking step, the tip of the tip is pressed against the opening edge of the drilling formed in the drilling forming step.   A tip tool for an impact tool used in the work breaking method according to claim 1.

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