JPH0112911Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a reamer for a thread cutting machine in which a conical piece formed into a conical shape with a plurality of radial protrusions is attached to a support arm, and the cutting blade mounting position of each protrusion is This eliminates the hassle of adjusting the mutual relationships between
This has been improved so that the inner surface of the tube tip can be chamfered by attaching a single cutting tool.

As shown in FIG. 1, a conventional reamer for a thread cutting machine has one cutting blade c at each inclined ridgeline of a plurality of radial protrusions b provided on a conical piece a.
, and its cutting edge is aligned with the imaginary circle d of each part in the length direction centered on the center of the conical piece a, and if only one of the blades c protrudes from the imaginary circle d, it will fit inside the pipe. Not only does the single blade c bear the burden of chamfering the surface, and the other blades are idle due to the cutting action, but also cutting resistance is applied to the single blade c, causing the conical piece to vibrate and generate noise. Moreover, the blade was chipped. Moreover, in order to eliminate such a defect, it is necessary to perform mutual adjustment so that the cutting edge of the cutting blade c of each projection piece b coincides with the virtual circle d, which is a defect that makes the work difficult.

In addition, as disclosed in Japanese Patent Publication No. 44-4590, several grooves are formed at equal angular intervals on the outer periphery of a conical holder having no radial protrusions, and the bottom of each groove is made of rubber. A reamer is known in which a plate or the like is laid down, a guide piece protruding from the outer periphery of a conical support is fitted, and a cutting blade protruding from the outer periphery of the support is fixed at an appropriate position between the guide pieces. Although the purpose is partly the same as that of the present invention, groove cutting,
There is a drawback that manufacturing is complicated because it is necessary to fit the elastic plate and the guide piece, and to attach and fix the cutting blade to the conical holder that has no projections in the radial direction. The present invention is aimed at eliminating such defects, and one embodiment thereof will be described with reference to FIGS. 2 to 5.

FIG. 2 is a side view showing an outline of the thread cutting machine, in which the support arm 5 is swung upward and retracted by the shaft 3 of the protrusion provided on the rear side of the die head 2 supported by the frame 1. When in use, the free end 6 is placed on the support base 4 of the frame 1, crossing the rear center of the die head 2 as shown in the figure.

A plurality of conical pieces 7 aligned with the center of the die head 2 are attached to the support arm 5 in a horizontally elongated manner with protruding pieces 8 projecting at equal angular intervals, and a rod-shaped handle 9 protruding rearward is attached to the center of the conical pieces 7.

As shown in FIG. 3, each of the projecting pieces 8 has one piece serving as a blade attachment piece 11, and the other two pieces serving as contact pieces 12, 12 for contacting the inner surface of the threaded pipe, and each contact piece has a respective protruding surface 13, 13 is matched with a circular arc surface that matches a virtual circle 21 centered on the center of the conical piece 7. The virtual circle 21 sequentially reduces the radius of each part of the conical piece 7 in the length direction.

The blade mounting piece 11 is designed to have a slight gap between it and the virtual circle 21 as shown in FIG. A cutter attachment surface 14 is formed by cutting into an L shape, and a cutting knife 15 having a cutting edge 16 slightly protruding from the virtual circle 21 is removably attached to the surface 14 with a screw 17.

In the present invention, the conical piece 7 is inserted relatively into the center of the tip of the threaded tube, which is gripped by the chuck and moves backward while rotating around the center of the die head 2, in the same way as in the past, and the inner circumference of the end surface of the tube is Chamfering is performed by one cutting blade 15, and several other contact pieces 12 are brought into contact with the inner circumferential surface of the pipe, and the cutting blades 15 are attached to each protruding piece to determine the mutual mounting position. That is, since it does not adjust the degree of protrusion of the cutting edge 16, it has the function of facilitating the attachment and replacement of the cutting edge 16, and also allows the other protruding piece to which the cutting blade is not attached to take over the guiding action as the contact piece 12. Therefore, the relative approach movement between the threaded pipe and the conical piece can be stabilized, and the assembly structure can be simplified compared to the reamer disclosed in Japanese Patent Publication No. 44-4590 (mentioned above). It has the advantage of being easier to manufacture and can be manufactured with a simple structure suitable for thread cutting machines that often cut threads on thin pipes with an inner diameter of about 15 mm.

[Brief explanation of the drawing]

Fig. 1 is an end view of a conventional reamer for thread cutting machines, Fig. 2 is a schematic side view of the reamer of the present invention, Fig. 3 is a plan view of the reamer of the present invention, Fig. 4 is a perspective view thereof, and Fig. 5 is a back front view. It is a diagram. 2→Die head, 5→Support arm, 7→Conical piece, 8→Protrusion piece, 11→Cutter mounting piece, 12, 12
→ Contact piece, 14 → Blade mounting surface, 15 → Cutting blade, 2
1 → virtual circle.

Claims (1)

[Scope of utility model registration request] In a reamer for a thread cutter, in which a plurality of protrusions 8 protruding in the radial direction are arranged at approximately equal angular intervals on a support arm 5 that is moved to a position crossing the rear center of the die head during use, one of the protrusions 8 is The blade mounting piece 11 is used as a contact piece 12, and the protruding surface 13 of the other piece is used as a contact piece 12. The blade mounting piece 11 is cut off in an L shape on the front side in the rotational direction to form a blade mounting surface 14, and a cutting blade 15 is attached to the surface 14. A reamer for a thread cutting machine characterized by being removably attached.