JPS6344481B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting tool in which a head with a cutting edge is detachably attached to a holder.

Conventional cutting tools had a head with a cutting edge formed integrally with a holder, so the entire tool had to be replaced each time the type of cutting process changed. It takes time, requires a large space to store tools, and is heavy, which poses a problem in terms of safety during replacement work.

SUMMARY OF THE INVENTION Accordingly, a primary object of the present invention is to provide a cutting tool which solves the above-mentioned problems by forming a head and a holder separately and attaching the head to the holder in a detachable manner. A second object of the present invention is to provide a cutting tool that allows the head to be attached and detached easily and accurately.

In order to achieve the above object, the cutting tool of the present invention has a head equipped with a cutting edge formed separately from a holder, and a shaft protruding from the head inserted into a fitting hole provided in the holder. , in a cutting tool in which the head and the holder are fixed integrally, recesses and protrusions having a uniform width in the circumferential direction are alternately formed on the outer periphery of the shaft part, and on the inner periphery of the fitting hole. A concave portion and a convex portion respectively corresponding to and having the same width as the convex portion and concave portion are provided, and the width of the convex portion of the shaft portion is narrower than the width of the convex portion of the fitting hole, and the two convex portions are mutually arranged. A coupling pin is provided in the center of the fitting hole of the holder so as to be able to move forward and backward, and the protruding end is engaged with the engagement hole provided in the center of the head shaft. A notch is provided in the shaft of the coupling pin that is removably inserted, and a part of the clamp member attached to the holder is engaged with the notch, and is also fitted with the outer peripheral surface of the shaft on the opposite side of the notch. It has a structure in which a plurality of steel balls are interposed between the hole and the inner circumferential surface of the hole.

Align and fit the protrusion on the outer circumference of the head shaft with the protrusion on the inner circumference of the holder fitting hole, and at the same time insert the head of the coupling pin into the engagement hole of the head. Thereafter, the heads are rotated relatively to position the former protrusion in close contact with the latter protrusion, and the coupling pin is engaged with the head. Thereafter, the clamp member is tightened to engage the coupling pin with the notch, and the head and holder are integrated by retracting the coupling pin.

When replacing the head, after loosening the clamp member, rotate the head so that its protrusion faces the recess of the holder, remove the coupling pin from the engagement hole, and remove the head.

The present invention will be described below based on embodiments shown in the accompanying drawings.

The embodiment shown in the drawings is an example in which the present invention is applied to a boring tool, and as shown in FIG.
The head 1 and the holder 2 are formed separately, and a connecting pin 3 is interposed between the two to connect the head 1 to the holder 2.
It is designed to be removably attached to the body. The head 1 is provided with a cutting blade 4 at its tip, and a fitting shaft portion 5 of one step smaller diameter protrudes from its rear end surface.
As shown in FIG. 4, convex portions 6, 6 are formed on the outer circumferential surface of the fitting shaft portion 5 over an angular range slightly smaller than 90 degrees at axially symmetrical positions.
Recesses 7, 7 are formed between them over an angular range slightly larger than 90 degrees. That is, convex portions 6 and concave portions 7 having a constant width are alternately formed on the outer peripheral surface of the shaft portion 5, and the width of the convex portions 6 is formed to be narrower than the width of the concave portions 7. Further, an oval insertion hole 8 is formed in the end surface of the shaft portion 5, that is, a hole 8 whose two opposing sides are parallel and whose other two opposing sides are arc-shaped, and is located deep inside the hole 8 along the arc. By forming the ivy circular engagement hole 9,
Half-moon-shaped engagement walls 10, 10 are formed.

The coupling pin 3 is composed of a head 11 and a shaft 12, and the head 11 has an oval shape that can freely go in and out of the insertion hole 8, and protrudes like a brim to both sides of the shaft 12. (See Figure 5).

Furthermore, as shown in FIGS. 1 and 3, a large-diameter fitting hole 13 and a small-diameter fitting hole 14 are formed in two stages on the distal end surface of the head 2, and the fitting shaft of the head 1 is formed in two stages. 5 and the shaft portion 12 of the coupling pin 3 into these fitting holes 1.
It is inserted in 3 and 14. Further, on the inner circumferential surface of the large-diameter fitting hole 13, a convex portion 6 of the fitting shaft portion 5 is provided.
and a recess 15 corresponding to and having the same width as the recess 7,
15 and protrusions 16, 16 are respectively formed, and the protrusion 6 of the head 1 and the protrusion 16 of the holder 2 are formed in close contact with each other (see FIG. 5). Furthermore, a key 17 for positioning and locking the head 1 when it is inserted is provided in a part of the large-diameter fitting hole 13, as shown in FIG.

A spring 1 is located deep inside the small diameter fitting hole 14.
8 is housed therein, and the shaft portion 12 of the coupling pin 3 is inserted therein. The shaft portion 12 of the coupling pin 3 includes
As shown in FIG. 1, a notch 19 is formed.
Further, a screw hole 20 is provided that penetrates diagonally from the outer peripheral surface of the holder 2 to the small-diameter fitting hole 14, and the tip of a fixing screw 21 screwed into the screw hole 20 is engaged with the slope of the notch 19. The spring 18 is then compressed to retract the coupling pin 3. In order to prevent the head 11 from being lifted upward using one end of the shaft 12 as a fulcrum when the coupling pin 3 is pulled in by the fixing screw 21, the shaft 1 is
Several steel balls 22 are placed on the outer periphery on the opposite side of the notch 19 of 2.
is wearing. Further, a long groove 23 is provided on the side surface of the shaft portion 12.
As shown in FIG. 7, a key screw 24 inserted from the outer periphery of the holder 2 is engaged with the key screw 24 to prevent the coupling pin 3 from rotating or coming off.

Note that the fixing screw 21 may have a truncated conical tip as shown in FIG. good. In addition, instead of the above fixing screw 21, an eccentric cylindrical cam 25 is incorporated as shown in FIG. The coupling pin 3 may be retracted by rotating the coupling pin 25 from the outside.

The cutting tool of this invention is configured as described above,
When the head 2 is positioned with respect to the holder 1 using the key 17 and inserted, the protrusions 6, 6 of the head 1 are inserted.
is loosely fitted into the recess 15 of the holder 2, as shown in FIG. 6, and the recess 7 of the head 1 is loosely fitted into the protrusion 16 of the holder 2. At the same time, the head 11 of the coupling pin 3 passes through the insertion hole 8 of the head 1 and reaches the engagement hole 9 located deep inside. Then, when the head 1 is rotated about 90 degrees relative to the holder 2, as shown in FIG. The collar-shaped portion of the head 11 of No. 3 engages with the engagement wall 10. Thereafter, when the fixing screw 21 is tightened, the coupling pin 3 is retracted, and the head 1 is fixed to the holder 2 via the coupling pin 3. Conversely, when the fixing screw 21 is loosened, the coupling pin 3 is pushed out by the spring 18, so that the head 1 is quickly released. Note that even if the fixing screw 21 is loosened too much, the coupling pin 3 will not fall out because the key screw 24 is engaged with the long groove 23. Further, the cutting force during operation is received by the holder 2 via the key 17.

As described above, in this invention, the head and holder are formed separately, and the head is detachably attached to the holder. Therefore, when changing the cutting mode, only the head needs to be replaced. In addition to being able to be replaced quickly, it is only necessary to store the required types of heads, which are significantly smaller than the entire tool, so that the storage space is small and the safety of the replacement work is improved. Further, in the fitting portion between the head and the holder, due to the corresponding structure of the concave and convex portions formed on the fitting surfaces of both, wobbling can be prevented by the close contact between the convex portions. Furthermore, the head is clamped to the holder via a coupling pin,
Since the coupling pin is attached to the holder, it also has the advantage of being lighter in weight than a structure in which the fitting protrusion is integrally formed with the holder.

Further, by interposing a plurality of steel balls between the outer circumferential surface of the shaft portion on the opposite side of the notch portion and the inner circumferential surface of the fitting hole, there is an effect that the coupling pin can be smoothly retracted.

[Brief explanation of drawings]

Figure 1 is a vertical front view, Figure 2 is a left side view of the head, Figure 3 is a left side view of the holder, Figure 4 is a right side view of the head, and Figure 5 is a cross section taken along the - line in Figure 1. 6 is a sectional view taken along the - line in a loosely fitted state, FIG. 7 is a sectional view taken along the - line in FIG. 1, and FIGS. 8 and 9 are partially omitted longitudinal sectional front views of other embodiments. It is. DESCRIPTION OF SYMBOLS 1... Head, 2... Holder, 3... Connecting pin, 4... Cutting blade, 5... Shaft portion, 6... Convex portion, 7...
... recess, 8 ... insertion hole, 9 ... engagement hole, 10 ...
Engagement wall, 11...head, 12...shaft, 13...
Large diameter fitting hole, 14...Small diameter fitting hole, 15...Concave portion, 16...Convex portion, 21...Fixing screw, 22...
Steel ball, 25...cylindrical cam.

Claims (1)

[Scope of Claims] 1. A head equipped with a cutting edge is formed separately from a holder, and a shaft portion protruding from the head is inserted into a fitting hole provided in the holder to fix the head and holder together. In such a cutting tool, concave portions and convex portions having a uniform width in the circumferential direction are alternately formed on the outer periphery of the shaft portion, and the convex portions and convex portions are also formed on the inner periphery of the fitting hole, respectively. In addition, a concave portion and a convex portion having the same width as these are provided, so that the width of the convex portion of the shaft portion is narrower than the width of the convex portion of the fitting hole, and the protrusion amount of both convex portions is such that they can come into close contact with each other. A coupling pin is formed in the center of the fitting hole of the holder and protrudes so as to be able to move forward and backward,
The protruding end is detachably inserted into the engagement hole provided in the center of the head shaft, a notch is provided in the shaft of the coupling pin, and a part of the clamp member attached to the holder is inserted into the notch. A cutting tool characterized in that a plurality of steel balls are interposed between the outer circumferential surface of the shaft portion on the opposite side of the notch portion and the inner circumferential surface of the fitting hole. 2. An oval head is provided at one end of the shaft of the coupling pin that protrudes like a brim to both sides, and an oval insertion hole is formed in the center of the head through which the head can pass. The cutting tool according to claim 1, characterized in that a circular engagement hole is provided in a deep part.