JPS5848004Y2 - spring collect - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a spring collet for use in, for example, a drill holder, tap holder, reamer holder, etc., and for holding a tool shank.

For example, as shown in FIG. 1, when attaching a tool such as a drill 2 to a holder body 1, it is customary to use an elastic collet 3.

That is, a collet 3 having a tool insertion hole 4 in the center and having a tapered outer shape is inserted into the tapered center hole 5 of the holder body 1.
The collet 3 is screwed into a lock nut 6 so as to be slidable in the axial direction.

Then, insert the drill 2 into the tool insertion hole 4 of the collet 3,
When the collet 3 is pushed deep into the center hole 5 with the lock nut 6, the collet 3 is tightened by the center hole 5 and the drill 2 is tightened.

In order to further exhibit the tightening effect, as shown in FIG. 2, a plurality of grooves 9 and 10 are formed in the large diameter portion 7 and small diameter portion 8 of the collet 3, respectively, to provide elasticity. Spring collets are also used.

However, this spring collet has a problem in that chips enter through the grooves 9 of the large diameter portion 7 during machining, resulting in a decrease in the holding accuracy of the holder.

Therefore, generally speaking, rubber 11 is inserted into the groove 9 as shown in FIG.
or fill the O-ring 12 as shown in Figure 4.
A dustproof cap 13 is used to cover the large diameter portion 7 so as to close the split groove 9 through the large diameter portion 7.

However, the former is relatively expensive and there is a risk that the rubber 11 will deteriorate and fall off due to the heat generated by the tool during cutting, while the latter has the drawback of increasing the number of parts and similarly increasing costs.

The purpose of the present invention is to provide a spring collet that does not require dust-proofing treatment and has an excellent springing effect under the above-mentioned current situation. The tool tightening collet has a threaded part and a tapered part on the outside, and an annular groove is provided around the border between the threaded part and the tapered part, and the ring groove is formed from the small diameter part side to the large diameter part of the tapered part. A plurality of grooves are carved in the groove, and the tip of each groove reaches at least the annular groove.

The present invention will be explained based on the embodiments shown in FIGS. 5 and 6.

The collet 3 has a tool insertion hole 4 drilled in the direction of the central axis, and a threaded portion 14 and a tapered portion 15 formed on the outside.

An annular groove 16 is provided near the boundary between the threaded portion 14 and the tapered portion 15.
has been established.

Also, a plurality of dividing grooves 17 are formed from the small diameter portion 8 to the large diameter portion 7.
is engraved, and its tip reaches at least the annular groove 16 at 1.

Each tightening piece 18 divided by the split groove 17 of this spring collet 3 has an annular groove 16 at its base and is thin, so that the elastic deformation of this thin wall portion can fully exert the elasticity effect. can.

Therefore, as shown in FIG.
If this is used to fix the drill 2, sufficient tightening can be obtained by the tightening piece 18, and there is no split groove in the large diameter portion 7, so there is no fear of chips entering.

The annular groove 16 is for elastically deforming the fastening piece 18, and its depth may be set to the minimum thickness that provides the necessary elastic deformation and does not buckle.

Further, the cross-sectional shape of the annular groove 16 can be arbitrarily selected such as a semicircular shape or a slit shape, and its position is preferably near the boundary between the threaded portion 14 and the tapered portion 15.

The number of grooves 17 also has a great deal to do with the magnitude of elastic deformation, and generally four or more grooves are desirable.

As explained above, the spring collet according to the present invention does not have split grooves in the large diameter part, but only in the small diameter part, and allows elastic deformation through the thin walled part of the annular groove. The tightening effect is comparable to that of a structure in which split grooves are provided from both sides of the collet and the small diameter part, and it has the advantage that chips do not enter the collet.

[Brief explanation of the drawing]

Figure 1 is a partial sectional view of a tool being tightened using a collet, Figure 2 is a perspective view of a conventional spring collet,
FIGS. 3 and 4 are explanatory diagrams of measures to prevent chips from entering a conventional spring collet, FIG. 5 is a perspective view of a spring collet according to the present invention, and FIG. 6 is a sectional view thereof. 3 is a collet, 7 is a large diameter portion, 8 is a small diameter portion, 14 is a threaded portion, 15 is a tapered portion, 16 is an annular groove, 17 is a split groove,
18 is a tightening piece.

Claims (1)

[Scope of utility model registration request] This collet for tool tightening has a drill insertion hole in the direction of the central axis, and a threaded part and a tapered part on the outside. Multiple grooves are carved from the small diameter side to the large diameter side,
A spring collet characterized in that a tip of each split groove reaches at least the annular groove.