Nikken Kosakusho Works, Ltd.

Yusaku Yamamoto

Masahiro Taguchi

Masakazu Matsumoto

Eisaku Nakai

Hisashi Ide

A chuck includes a holder body, a clamp sleeve, and a large number of needle rollers. The holder body has a shank portion, a flange, and a chuck sleeve. The clamp sleeve is fitted onto the outer circumference of the chuck sleeve such that the clamp sleeve is rotatable and axially movable relative to the chuck sleeve. The needle rollers are disposed between the chuck sleeve and the clamp sleeve over the entire circumference. The clamp sleeve is rotated to cause the needle rollers to revolve spirally along the outer circumferential surface of the chuck sleeve while rotating about their own axes in order to decrease and restore the diameter of the chuck sleeve. A thrust member is disposed between the end surface of the flange opposite the shank portion and a corresponding end surface of the clamp sleeve.

Chuck

In order to provide a tool holder which greatly reduces frictional resistance between a locknut and a taper collet, and eliminates a twisting of the taper collet during tightening of the locknut, in a tool holder comprising a locknutwhich pushes a taper colletinto a tapered holeof a collet chuck bodyto chuck a cutting tool, between a reference endof the tape colletand a collet supporting portionopposed thereto, interposed is a bearing washerto reduce frictional resistance between both contact surfaces. To both surfaces of this bearing washer, namely, to the respective surfaces which come into contact with the reference endand collet supporting portion, surface treatment by any of ion nitriding, DLC (Diamond-Like Carbon) coating, and TiN coating is applied.

Tool holder

An end mill chucking structure for chucking an end mill having a relatively small diameter and used, for example, for deep milling of a die. The end mill chucking structure includes an end mill holder and an end mill. A holder body has a taper hole formed therein. The end mill includes an end mill body and a cutting tip provided at an end portion of the end mill body. A portion of the end mill body located opposite the cutting tip serves as a tapered shank portion. The shank portion and the rest of the end mill body are bounded by a shoulder extending outward from the surface of the shank portion. The shank portion is press-fitted or shrink-fitted into the taper hole such that the end face of the holder body abuts the shoulder of the end mill body, through application to the holder body of heat at a temperature lower than a conventional shrink-fitting temperature.

End mill chucking structure

A tool holder includes a holder body which in turn includes a shank portion, a flange portion, and a tool attachment portion; a taper cone fitted to the shank portion; an elastic member interposed between a rear-end face of the flange portion and a front-end face of the taper cone; and a stopper member disposed on the shank portion so as to support a rear-end face of the taper cone. The outer surface of the taper cone is tapered at an angle equal to that at which the wall surface of a taper hole formed in a spindle of a machine tool is tapered. The inner surface of the taper cone and the outer surface of the shank portion are equally tapered at an angle smaller than the angle at which the outer surface of the taper cone is tapered. Through drawing of the holder body, the taper cone expands radially to thereby be tightly held within the taper hole. A spacer is bonded to the end face of the spindle so as to eliminate a gap which is formed between the flange portion and a spindle.

Tool holder and tool holder attachment mechanism

An article clamping apparatus is designed to compulsorily open the front end portions of divided pieces of a collet and to allow the divided pieces of the collet to securely hold a pull stud of a tool holder. A draw bar is fitted into a spindle of the machine tool, and a support sleeve is disposed to surround the draw bar via the collet. A separator is disposed on the front side of the support sleeve and fixed to the spindle together with the support sleeve. The positioning plates provided on the separator are engaged with slit grooves of the support sleeve and inserted between the divided pieces of the collet. Upon advancement of the draw bar, the divided pieces are advanced, so that the front end slat surfaces of the divided pieces contact the slant surfaces of the collet opening projections provided on the separator so as to compulsorily open the front portions of the divided pieces. Subsequently, the engagement portion of the pull stud is inserted into the front portion of the collet, and the draw bar is retracted, so that the engagement portion of the pull stud is engaged with the front inside projections of the divided pieces.

Clamping apparatus for a spindle of a machine tool

A tool holder has a main sleeve to be attached to a tapered bore of a spindle of a machine tool, and a subholder which is coupled with the main sleeve and to which a tool is attached. The tapered shank of the main sleeve is inserted into the tapered bore of the spindle having a taper of 7/24. The main sleeve has a tapered hole having a taper of 1/10. A tapered sleeve which is elastically deformable in the radial direction is fitted onto the outer circumference surface of a shank portion of a subholder body of the subholder. The subholder is coupled with the main sleeve such that the outer circumferential surface of the tapered sleeve having a taper of 1/10 intimately contacts the circumferential surface of the tapered hole and the rear end surface of a flange of the subholder body intimately contacts the forward end surface of the main sleeve. This structure prevents the generation of vibrations during machining. Also, the tool holder makes it possible to efficiently machine a workpiece at high speed, and to increase the durability of the tool and the spindle.

Growing community of inventors

Osaka, Japan

Yusaku Yamamoto