CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/JP2017/024757 filed Jul. 6, 2017, claiming priority based on Japanese Patent Application No. 2016-236896, filed Dec. 6, 2016.

TECHNICAL FIELD

The present invention relates to a chuck apparatus.

BACKGROUND ART

As disclosed in patent document 1, in the past there have existed chuck apparatuses in which a rotating cylinder disposed in a body is caused to rotate, and jaws screwed together with a rotary nut that rotates together with the rotating cylinder are expanded or contracted and advanced or retracted by rotation of the rotary nut, and a tool is held by the jaws.

The chuck apparatus disclosed by patent document 1 is provided with an anti-slackness mechanism in which there are used ratchet teeth provided to the body, and a locking spring body that is provided between the rotating cylinder and the ratchet teeth and locks with the ratchet teeth. In a state in which the ratchet teeth and the locking spring body are locked, a portion of the locking spring body is fitted into a depression provided in an inner surface of the rotating cylinder, and the locked state is maintained.

Therefore, after rotating the rotating cylinder in a tightening direction, and locking the ratchet teeth and the locking spring body to cause the tool to be held by the jaws, when the tool is to be removed, the lock between the ratchet teeth and the locking spring body must be released prior to rotating the rotating cylinder in a loosening direction to expand and open the jaws.

To release the lock between the ratchet teeth and the locking spring body, the rotating cylinder must be twisted to cause the portion of the locking spring body to be ejected from the depression, and an appropriate amount of force is required to release the lock between the ratchet teeth and the locking spring body.

A problem is also presented in that wear of the ratchet teeth due to the locking between the locking spring body and the ratchet teeth is accelerated due to the locked state being maintained.

PRIOR ART DOCUMENTS

Patent Documents

[Patent Document 1] Japanese Laid-open Patent Publication No. 2005-305574

DISCLOSURE OF THE INVENTION

Problem to be Solved by the Invention

The present invention was conceived in light of the current state of the art as indicated above, it being an object thereof to provide a chuck apparatus of highly exceptional practical utility in which there is provided a lock release mechanism whereby, after the rotating cylinder has been rotated in the tightening direction and tightening has been completed, the lock between the ratchet teeth and the locking spring body is forcibly released when a user releases their hand and the rotational force in the tightening direction is brought to zero. As a consequence, it is simpler to rotate the rotating cylinder in the loosening direction when replacing the tool, and wear of the ratchet teeth is suppressed, so that the service life is increased.

Means for Solving the Problem

The main points of the present invention are described below with reference to the accompanying drawings.

A first aspect of the present invention relates to a chuck apparatus for expanding or contracting, by rotating a rotating cylinder1, a plurality of jaws3inserted into a hole2aprovided to a tip end of a body2, and sandwiching and holding a tool4using the jaws3; the chuck apparatus being characterized in that an annular rotating body8screwed together with the jaws3and rotating together with the rotating cylinder1is fitted to the body2inside the rotating cylinder1; annular ratchet teeth5are provided to the body2or the rotating body8; a detachable locking spring body9for locking with the ratchet teeth5is provided; and a lock release mechanism is provided for forcibly releasing the lock between the ratchet teeth5and the locking spring body9when a rotational force in a tightening direction is set to zero after the rotating cylinder1has been rotated in the tightening direction and a holding force on the tool4has reached a predetermined value.

Furthermore, a second aspect of the present invention relates to the chuck apparatus of the first aspect, characterized by providing at an inner surface of the rotating cylinder1, a pressing deformation part11for pressing and elastically deforming a to-be-pressed part9aof the locking spring body9when the rotating cylinder1is rotated in the tightening direction, and adopting the lock release mechanism for forcibly releasing the locking between the ratchet teeth5and the locking spring body9by pushing back the pressing deformation part11via a repelling force due to restoral deformation of the to-be-pressed part9aand rotating the rotating cylinder1in the loosening direction when the rotational force in the tightening direction is brought to zero after the rotating cylinder1has been rotated in the tightening direction and tightening has been completed.

Moreover, a third aspect of the present invention relates to the chuck apparatus of the first or second aspect, characterized by providing, at an inner surface of the rotating cylinder1, a pressing part10for pressing the locking spring body9not locked with the ratchet teeth5to thereby lock the locking spring body9with the ratchet teeth5when the rotating cylinder1is rotated in the tightening direction in which the jaws3are contracted and closed.

Effect of the Invention

In being configured as described above, the present invention provides a chuck apparatus of highly exceptional practical utility, in which rotation of the rotating cylinder in the loosening direction when replacing a tool is facilitated, and wear of the ratchet teeth is suppressed, so that the service life is increased.

