Abstract:
A chuck device that prevents wear of ratchet teeth is provided. The chuck device includes a rotary sleeve which is rotated so that jaws inserted into a hole provided in a tip end of a body are slidingly opened and closed to thereby clamp a tool. Ratchet teeth forming an annular shape are provided in the body, an annular rotary member threadedly engaged with the jaws and rotated together with the rotary sleeve is fitted around the body inside of the rotary sleeve, a retainer spring member detachably engaging with the ratchet teeth is disposed outside of the ratchet teeth and the retainer spring member is provided so as to rotate a circumference of the ratchet teeth in accordance with the rotation of the rotary member. The ratchet teeth are formed of a harder member than the body, and the harder member is a discrete member from the body.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a chuck device for clamping a tool. 
   BACKGROUND OF THE INVENTION 
   A chuck device having a looseness preventing mechanism is proposed as a chuck device having a structure described in Japanese Patent Application No. 2001-260708 (patent publication 1) assigned to the present assignee. Incidentally, since the structure thereof is the same as that of a first embodiment of the invention, the structure will be described with reference to  FIGS. 1 to 4 . 
   In such a chuck device having a looseness preventing mechanism, a rotary sleeve  1  is rotated so that a plurality of jaws  3  inserted into a hole  2   a  formed at a tip end of a body  2  is slidingly opened and closed; a tool  4  is clamped by the jaws  3 ; ratchet teeth  5  forming an annular shape are provided on the body  2 ; an annular rotary member  17  engaged with the jaws  3  and rotated together with the rotary sleeve  1  is fitted around the body  2  inside of the rotary sleeve  1 ; a retainer spring member  7  that is detachably engaged with the ratchet teeth  5  is arranged outside of the ratchet teeth  5 ; the retainer spring member  7  is provided so as to rotate around the ratchet teeth  5  together with the rotation of the rotary member  17 ; the retainer spring member  7  is mounted on the rotary member  17  by a convex and concave engagement means; and a holder portion for holding the condition that the engagement between the ratchet teeth  5  and the retainer spring member  7  is held and the disengagement between the ratchet teeth  5  and the retainer spring member  7  is held is provided. 
   By the way, in such a chuck device, it is proposed to manufacture the above-described body of light alloy such as aluminum in order to meet the requirement of weight reduction. However, since the ratchet teeth are formed by machining the ratchet teeth directly to the body, if the body is made of light alloy such as aluminum, then the ratchet teeth themselves are made of light alloy. 
   However, since the ratchet teeth are continuously and repetitively engaged with the retainer spring member made of steel, if the ratchet teeth are made of light alloy such as aluminum that is softer than the steel, the ratchet teeth are easily worn due to the continuous and repetitive engagement so that the looseness preventing mechanism does not work. This is disadvantageous in durability and maintenance. 
   Although a publication of Japanese Patent Application No. 2002-024495 (patent publication 2) assigned to the present assignee discloses a point for applying a coating on surfaces of the body and the ratchet teeth to thereby prevent the wear of the above-described ratchet, it is currently demanded to enhance the durability of the ratchet teeth more. 
   Patent Publication: Japanese Patent Application No. 2001-260708 
   Patent Publication: Japanese Patent Application No. 2002-024495 
   SUMMARY OF THE INVENTION 
   Accordingly, in order to overcome the above-noted defects, an object of the present invention is to provide a chuck device that prevents wear of ratchet teeth with a simple structure to make it possible to enhance durability and maintenance and that is extremely excellent in practical use. 
   The essence of the invention will now be described with reference to the accompanying drawings. 
   According to a first aspect of the invention, there is provided a chuck device in which a rotary sleeve  1  is rotated so that a plurality of jaws  3  inserted into a hole  2   a  provided in a tip end of a body  2  is slidingly opened and closed to thereby clamp a tool  4  by the jaws  3 , characterized in that ratchet teeth  5  forming an annular shape are provided in the body  2 , an annular rotary member  17  threadedly engaged with the jaws  3  and rotated together with the rotary sleeve  1  is fitted around the body  2  inside of the rotary sleeve  1 , a retainer spring member  7  detachably engaging with the ratchet teeth  5  is disposed outside of the ratchet teeth  5 , the retainer spring member  7  is provided so as to rotate a circumference of the ratchet teeth  5  in accordance with the rotation of the rotary member  17 , the retainer spring member  7  is mounted on the rotary member  17  by a concave and convex engagement means, furthermore, a holding portion for holding a condition that the ratchet teeth  5  and the retainer spring member  7  are engaged with each other and a condition that a disengagement between the ratchet teeth  5  and the retainer spring member  7  is released and the ratchet teeth  5  are formed of a harder member  13  than the body  2 , and the harder member  13  is a discrete member from the body  2 . 
   According to a second aspect of the invention, in the chuck device according to the first aspect, the ratchet teeth  5  are used which are made of a strip-like hard material  13  to be wrapped around a circumferential surface of the body  2 . 
   According to a third aspect of the invention, in the chuck device according to the second aspect, a recess fixture portion  14  to which the strip-like hard member  13  is fixed is provided in the circumferential surface of the body  2 . 
   According to a fourth aspect of the invention, in the chuck device according to the second aspect, the strip-like hard member  13  has both ends formed into perpendicular ends  13   b  to side edges thereof or slant ends  13   a.    
   According to a fifth aspect of the invention, in the chuck device according to the third aspect, the strip-like hard member  13  has both ends formed into perpendicular ends  13   b  to side edges thereof or slant ends  13   a.    
   According to a sixth aspect of the invention, in the chuck device according to the first aspect, the hard member  13  is made of the material selected from the group consisting of steel and stainless steel. 
   According to a seventh aspect of the invention, in the chuck device according to the first aspect, the body  2  is made of light material. 
   According to an eighth aspect of the invention, in the chuck device according to the seventh aspect, the light material is one selected from the group essentially consisting of non-iron material such as aluminum, magnesium and titanium, alloy thereof, synthetic resin or fiber reinforced resin. 
   Also, according to a ninth aspect of the invention, the chuck device according to the first aspect, the retainer spring member  7  is held in a predetermined position so that the holding portion may hold a condition that the ratchet teeth  5  and the retainer spring member  7  are engaged with each other and a condition that the engagement between the ratchet teeth  5  and the retainer spring member  7  is released. 
   Also, according to a tenth aspect of the invention, there is provided a chuck device in which a rotary sleeve  1  is rotated so that a plurality of jaws  3  inserted into a hole  2   a  provided in a body  2  is slidingly opened and closed to thereby clamp a tool  4  by the jaws  3 , characterized in that ratchet teeth  5  forming an annular shape are provided in the body  2 , an annular rotary member  17  threadedly engaged with the jaws  3  and rotated together with the rotary sleeve  1  is fitted around the body  2  inside of the rotary sleeve  1 , a retainer spring member  30  and  31  detachably engaging with the ratchet teeth  5  is disposed outside of the ratchet teeth  5 , the retainer spring member is composed of two spring members  30  and  31 , one of the spring members  30  functions to perform the retaining effect with the ratchet teeth  5 , the other retainer spring member  31  holds the position of the rotary sleeve  1  to thereby function to hold the position of the one retainer spring member  30 , the retainer spring members  30  and  31  are provided to rotate around the ratchet teeth  5  according to the rotation of the rotary member  17 , the retainer spring members  30  and  31  are mounted on the rotary member  17  by a concave and convex engagement means, a holding portion is provided for holding a condition that the ratchet teeth  5  and the one retainer spring member  30  are engaged with each other and a condition that the engagement between the ratchet teeth  5  and the one retainer spring member  30  is released, the holding portion is disposed between the body  2  and the rotary sleeve  1  and composed of the inner surface of the rotary sleeve  1  and the other retainer spring member  31 , the body  2  is made of light material such as aluminum or aluminum alloy, and the ratchet teeth  5  forming the annular shape are made of a harder material than the body  2  and a discrete member from the body  2 . 
   According to an eleventh aspect of the invention, in the chuck device according to the tenth aspect, the condition that the ratchet teeth  5  and one retainer spring member  30  are engaged with each other and the condition that the engagement between the ratchet teeth  5  and the one retainer spring member  30  is released are maintained by the concave and convex engagement of the other retainer spring member  31  and the rotary sleeve  1 . 
   According to a twelfth aspect of the invention, the chuck device according to any one of the first to eleventh aspects, the ratchet teeth  5  have a coating layer which is hard and has a frictional coefficient as small as possible. 
   With such a structure according to the present invention, it is possible to provide a chuck device that prevents wear of ratchet teeth with a simple structure to make it possible to enhance durability and maintenance and that is extremely excellent in practical use. 
   BEST MODE FOR EMBODYING THE INVENTION 
   A possible best mode for embodying the invention will briefly be described with reference to the accompanying drawings with effects of the invention. 
   Since the ratchet teeth  5  are made of harder material than a body  2  made of light alloy such as aluminum or the like, even if the ratchet teeth  5  are continuously and repetitively engaged with a retainer spring member  7  made of, for example, steel, the wear of the ratchet teeth  5  is prevented as much as possible. Thus, ratchet teeth are excellent in durability and maintenance. Accordingly, it is possible to provide a chuck device that prevents wear of ratchet teeth with a simple structure to make it possible to enhance durability and maintenance and that is extremely excellent in practical use. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a fragmentary frontal view from which a part of a first embodiment has been removed. 
       FIG. 2  is an exploded perspective view of the first embodiment. 
       FIG. 3  is a cross-sectional view taken along the line III-III of  FIG. 1  which shows the operation of the first embodiment. 
       FIG. 4  is a cross-sectional view taken along the line IV-IV of  FIG. 1  which shows the operation of the first embodiment. 
       FIG. 5  is an exploded perspective view of a second embodiment. 
       FIG. 6  is a cross-sectional view of the second embodiment corresponding to  FIG. 3 . 
       FIG. 7  is a cross-sectional view of the second embodiment corresponding to  FIG. 4 . 
       FIGS. 8(   a ),  8 ( b ) and  8 ( c ) are schematic illustrative cross-sectional views showing manufacturing processes of the ratchet teeth. 
       FIG. 9  is a schematic illustrative view showing an end shape of a hard member of the first embodiment. 
       FIG. 10  is a schematic illustrative view showing an end shape of a hard member of another example. 
       FIG. 11  is a schematic illustrative view showing an end shape of a hard member of still another example. 
       FIG. 12  is a schematic illustrative view showing an end shape of a hard member of still another example. 
       FIG. 13  is a schematic illustrative view showing an end shape of a hard member of still another example. 
       FIG. 14  is a frontal view from which a part has been removed as another example. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Embodiment 1 
   A first embodiment of the invention will now be described with reference to the accompanying drawings. 
     FIGS. 1 to 4 ,  8 ( a ) to  8 ( c ) and  9  to  13  show the first embodiment applied to a chuck device to be used for a power rotary tool such as a so-called hummer drill, a vibration drill and a driver drill applying vibrations and shocks, which will now be described. 
   A body  2  is made of non-iron metal such as aluminum, magnesium and titanium, alloy thereof or light material such as synthetic resin or fiber reinforced resin. Incidentally, in the first embodiment, the body  2  is made of aluminum alloy. 
   Three jaws  3  are provided obliquely in a hole  2   a  formed in the body  2 . An annular nut member  6  that is engaged with screw portions  3   a  formed on outer surfaces of the jaws  3  are provided in engagement with the jaws  3 . 
   This nut member  6  is composed of divided nut segments and keeps its shape with a shape retaining ring  8 . 
   Incidentally, in the embodiment, a rotary member  17  is rotated together with a rotary sleeve  1  and engaged with the jaws  3 . In the first embodiment, the rotary member  17  is composed of the nut member  6  and the shape retaining ring  8 . Accordingly, in the first embodiment, although the nut member  6  is coupled with the rotary sleeve  1  and the rotary sleeve  1  is rotated to rotate the nut member  6 , it is possible to take, for example, a structure that the shape retaining ring  8  is coupled with the rotary sleeve  1  and the rotary sleeve  1  is rotated to rotate the shape retaining ring  8  and the nut member  6 . 
   Four projecting portions  6   a,    6   b,    6   c  and  6   d  for mounting a retainer spring member  7  on the nut member  6  so as to rotate together are provided on the nut member  6 . The projecting portions  6   a,    6   b,    6   c  and  6   d  are provided on the nut member  6  which is a necessary component. Since it is unnecessary to particularly provide a member in which the projecting portions  6   a ,  6   b ,  6   c  and  6   d  are provided, it is possible to simplify the structure for the first embodiment. 
   Ratchet teeth  5  forming an annular shape and engaging with a tip end retainer portion  7 ′ of the retainer spring member  7  are formed on the body  2  in the forward side of the nut member  6 . 
   The ratchet teeth  5  are formed of, for example, steel or stainless steel which is a harder member  13  than the body  2  and which is a discrete member from the body  2 . Incidentally, the ratchet teeth  5  of the first embodiment are made of steel. 
   More specifically, the ratchet teeth  5  are made from a strip-like hard member  13  to be wrapped around a circumferential surface of the body  2 . The hard member  13  is fixed to a recess fixture portion  14  for making possible to fix the strip-like hard member  13  provided around the circumferential surface of the body  2 . 
   Incidentally, in the first embodiment, the strip-like hard member  13  is used and wrapped around the circumferential surface of the body  2  to form the ratchet teeth  5 . However, it is possible to form the ratchet teeth  5  by using another means such as pressingly inserting an annular member, formed in advance in an annular shape, around the circumferential surface of the body  2 . 
   In the first embodiment, the ratchet teeth  5  are formed as follows. The strip-like hard member  13  having both ends formed into perpendicular edges  13   b  to side edges thereof as shown in  FIG. 9  is wrapped around the above-described recess fixture portion  14  (see  FIG. 8(   a )). This recess fixture portion  14  is plastically deformed by a suitable tool  15  to thereby fix the strip-like hard member  13  in place (see  FIG. 8(   b )). A suitable concave and convex shape is applied to the strip-like hard member  13  fixed to the recess fixture portion  14  by a tool  16  for forming the ratchet teeth  5  (see  FIG. 8(   c )). 
   Accordingly, as a matter of course, it is possible to form to the light body  2  the ratchet teeth  5  that is excellent in hardness and that is hard to be worn due to the engagement with the retainer spring member  7  in the easy method. In addition, since both ends of the hard member  13  are formed into the perpendicular edges  13   b  to the side edges as shown in  FIG. 9 , it is possible to positively fix the entire circumferential portion of the hard member  13  to the recess fixture portion  14  by utilizing the elongation when the concave and convex shape is applied to the strip-like hard member  13  by machining the hard member  13  with the tool  16  for forming the ratchet teeth  5 . It is therefore possible to prevent the end portions of the strip-like hard member  13  from peeling off. In this case, in particular, when the hard member  13  is wrapped around the circumferential surface of the body  2 , it is preferable that an interval of both ends thereof (indicated by A in  FIG. 9 ) be set to be not greater than a length of one tooth of the ratchet teeth  5 . 
   Incidentally, it is possible to use a strip-like hard member  13  whose both ends are formed into slant ends  13   a  which may be kept in engagement with each other as shown in  FIGS. 10 and 11 . In this case, it is possible to continuously form the teeth along the entire circumference without any gap by machining the hard member  13  with the tool  16  for forming the ratchet teeth  5 . Consequently, the engagement with the retainer spring member  7  may be performed well. (In any place, a tooth is formed.) 
   Also,  FIGS. 12 and 13  show other examples where both ends of the hard member  13  are formed into perpendicular ends  13   b  to the side edges in engagement with each other. 
   The engagement between the ratchet teeth  5  and the above-described tip end retainer portion  7 ′ makes it possible to exhibit the condition that the nut  6  may be rotated one way only (not capable of rotating in a reverse direction). Incidentally, the tip end retainer portion  7 ′ is adapted to come into contact with the strip-like hard member  13  forming the ratchet teeth  5  in a predetermined range (indicated by B in  FIG. 8(   c )). 
   Reference numeral  9  designates steel balls. Reference numeral  10  denotes a steel ball receiver. Since this steel ball receiver  10  has a resiliency, it is possible to prevent the rotary sleeve  1  from rotating more than necessary in a fastening direction due to the vibration or the shock torque of the power rotary tool. 
   The retainer spring member  7  is made of metal (iron or steel) and is arranged to be supported to the inner surface of the rotary sleeve  1  around the ratchet teeth  5 . Reference characters  1   b  and  1   e  denote projecting portions for transmitting the rotational force of the rotary sleeve  1  to the nut member  6 . Incidentally, if the rotational force of the rotary sleeve  1  is transmitted through the shape retaining ring  8 , it is possible to transmit the rotational force in the same manner. 
   As shown in  FIGS. 2 ,  3  and  4 , three projecting portions  7   a ,  7   b  and  7   c  and the tip end retainer portion  7 ′ to be engaged with the ratchet teeth  5  are provided on the retainer spring member  7 . A contact portion  7   d  in contact with the projecting portion  6   c  for well exhibiting a spring force is provided at the rear end. The opposite side of the contact portion  7   d  is received by the projecting portion  6   b.  The retainer spring member  7  is provided to rotate together with the nut member  6  by the projecting portions  6   a  and  6   b  of the nut member  6  and the projecting portions  7   a  and  7   b  of the retainer spring member  7 . 
   In the first embodiment, since the retainer spring member  7 , the projecting portions  1   b  and  1   e  and the projecting portions  6   a ,  6   b ,  6   c  and  6   d  are arranged substantially on the same circumference, it is possible to perform a compact design. 
   Incidentally, the mounting manner of the retainer spring member  7  and the nut member  6  is not limited to the above-described structure as far as both components are rotated together. Also, in the first embodiment, although the retainer spring member  7  is mounted on the nut member  6  by the concave and convex engagement means, it is possible to take a structure where the retainer spring member  7  is mounted on the shape retaining ring  8  by the concave and convex engagement means. 
   An intervening member  1   c  is provided on the inner surface of the rotary sleeve  1  for positively performing the disengagement between the tip end retainer portion  7 ′ of the retainer spring member  7  and the ratchet teeth  5 . The tip end retainer portion  7 ′ is received by a tip end tapered surface of the intervening member  1   c  so that the release of the engagement (threaded engagement) between the tip end retainer portion  7 ′ and the ratchet teeth  5  may positively be performed. 
   A depressing portion  1   d  for depressing the tip end retainer portion  7 ′ of the retainer spring member  7  and maintaining the engagement condition between the tip end retainer portion  7 ′ and the ratchet teeth  5  is formed on the inner surface of the rotary sleeve  1 . 
   The rotary sleeve  1  whose tip end is received to the body  2  is fitted around the nut member  6 . The rotary sleeve  1  is rotated together with the nut member  6 . However, when a predetermined load is applied to the rotation of the nut member  6 , the rotary sleeve  1  is adapted to rotate through a predetermined angle relative to the nut member  6 . 
   The rotation of the rotary sleeve  1  through the predetermined angle relative to the nut member  6  is defined between the projecting portion  6   a  and the projecting portion  6   b  and more specifically indicated by L in  FIG. 3 . Accordingly, when the rotary sleeve  1  rotates and the load is applied, the projecting portion  1   a  of the rotary sleeve  1  rides over the projecting portion  7   c  against the spring force of the retainer spring member  7  and the end face of the projecting portion  1   b  comes into contact with an end face M of the projecting portion  6   b.  (In the same manner, the end face of the projecting portion  1   e  comes into contact with the end face of the projecting portion  6   d .) Then, the rotary sleeve  1  and the nut member  6  become together to increase the fastening. 
   There is no fear that the rotary sleeve  1  is rotated in the loosening direction so far as the projecting portion  1   a  does not ride over the projecting portion  7   c  of the retainer spring member  7  against the spring force of the retainer spring member  7  due to the existence of the projecting portion  1   a.  Accordingly, to such an extent, it is possible to positively exhibit the looseness preventing effect. Incidentally, it is possible to set the looseness preventing force according to the spring force of the retainer spring member  7 , particularly the spring force between the projecting portion  7   b  and the contact portion  7   d  and the shape of the projecting portion  1   a  and the projecting portion  7   c.    
   Furthermore, slippage-preventing convex portions are formed on the outer surface of the rotary sleeve  1  (made of synthetic resin). Also, the rotary sleeve  1  is received by the receiving member  11  having a tip end to the body  2  and a rear end to the body  2 . 
   Incidentally, in the case where the power rotary tool such as a driver drill or the like is used, the rotary force is required for the machining work such as opening and closing the chucks or boring. However, in the case where the power rotary tool such as an impact driver, a hammer drill or a vibration drill or the like is used, since the holding force in the axial direction for preventing the pull-off is needed although the rotational force is necessary, it is preferable to use the coupling with a cross-knurled shape provided at the rear end of the body  2  for the coupling between the receiving member  11  and the body  2  (see  FIG. 14 ). Also, in some case, the receiving member  11  is received within the rotary sleeve  1  and in another case, the receiving member  11  is exposed outside of the rotary sleeve  1 . 
   Reference numeral  12  denotes a C-shaped pull-off preventing ring of the rotary sleeve  1 . 
   With such a structure in the first embodiment, the following effects are ensured. 
   When the rotary sleeve  1  is rotated while the tool  4  is being clamped by the jaws  3 , the rotary sleeve  1  and the nut member  6  are rotated together until the predetermined load is applied to the rotary sleeve  1 . Accordingly, also the retainer spring member  7  is rotated around the ratchet teeth  5 . 
   When the rotary sleeve  1  is rotated up to the predetermined position (where the jaws  3  are brought into contact with the tool  4 ), the predetermined load is applied to the rotary sleeve  1  (under the condition shown in  FIG. 3 ). When the rotary sleeve  1  is further rotated from this condition against the spring force in the direction indicated by the arrow in  FIG. 3 , the rotary sleeve  1  is rotated relative to the nut member  6 . The intervening member  1   c  for receiving the tip end retainer portion  7 ′ of the retainer spring member  7  is moved. At the same time, the depressing portion  1   d  of the rotary sleeve  1  depresses the tip end retainer portion  7 ′ so that the tip end retainer portion  7 ′ retains the ratchet teeth  5 . Furthermore, the projecting portion  1   a  of the rotary sleeve  1  rides over the projecting portion  7   c  of the retainer spring member  7 . (The projecting portion  7   c  is positioned from a T-side to an S-side in  FIG. 3 .) The projecting portion  1   b  is brought into contact with the end face M of the projecting portion  6   b  and in the same manner, the projecting portion  1   e  is brought into contact with the projecting portion  6   d  to form the rotary sleeve  1  and the nut member  6  together. Furthermore, when the rotary sleeve  1  is rotated, the tip end retainer portion  7 ′ of the retainer spring member  7  retained at the ratchet teeth  5  rides over the ratchet teeth  5  one by one by the leaf spring effect. (In this condition, no reverse rotation is generated due to the ratchet teeth  5 .) The rotational resistance of the rotary sleeve  1  is increased to complete the fastening operation (see  FIG. 4 ). 
   Incidentally, under the condition that the retainer spring member  7  rides over the ratchet teeth one by one, the fastening operation is not completed. If the fastening operation is completed, the ride-over of the teeth is not generated. 
   This fastened condition is kept by the projecting portion  7   c  and the projecting portion  1   a.    
   Also, in order to release the fastened condition, the steps are performed in the opposite order to that of the above-described steps. When the rotary sleeve  1  is rotated in the reverse direction, the projecting portion  7   c  located on the S-side (condition shown in  FIG. 4 ) rides over the projecting portion  1   a.  When the rotary sleeve  1  is further rotated in the direction indicated by the arrow in  FIG. 4 , the engagement (threaded engagement) between the tip end retainer portion  7 ′ and the ratchet teeth  5  by the depressing portion  1   d  is released. Furthermore, the intervening member  1   c  is moved to raise the tip end retainer portion  7 ′ of the retainer spring member  7 . The rotary sleeve  1  is further rotated to loosen the fastened condition of the tool  4 . This condition, i.e., the condition that the engagement between the tip end retainer portion  7 ′ of the retainer spring member  7  and the ratchet teeth  5  is released is retained by the projecting portion  7   c  and the projecting portion  1   a.    
   According to the first embodiment, it is possible to provide a chuck device that is excellent in durability with a simple structure and in which the looseness of the fastening operation of the tool  4  is positively prevented. 
   Also, since the body  2  is made of light material, the chuck device according to the first embodiment is excellent in practical use and in addition ratchet teeth  5  is made of harder material than the body  2  made of light material, the device is more excellent and it is possible to more effectively prevent the wear caused by the engagement with the retainer spring member  7 . The device is excellent in durability and maintenance. 
   The intervening member  1   c  according to the first embodiment is used so that the tip end retainer portion  7 ′ of the retainer spring member  7  is not accidentally engaged with the ratchet teeth  5 . (Accordingly, under the condition, i.e., the condition that the depressing portion  1   d  is not brought into contact with the tip end retainer portion  7 ′, the tip end retainer portion  7 ′ is separated away from the ratchet teeth  5  by the resiliency of the spring.) By dispensing with the depressing portion  1   d  or not using the depressing portion  1   d,  it is possible to threadedly engage the tip end retainer portion  7 ′ with the ratchet teeth  5  and to forcibly disengage the rip end retainer portion  7 ′ from the ratchet teeth  5  by the intervening member  1   c.    
   Also, it is possible to apply a coating layer that is hard and having a small friction coefficient as much as possible. In this case, even if chips are brought into collision with the body  2 , the body  2  is hardly damaged. Furthermore, since the coating layer is applied also to the ratchet teeth  5 , the wear of the ratchet teeth  5  is further prevented. At the same time, the engagement with and disengagement from the retainer spring member  7  is smoothly performed. The above-described coating layer is also applied to the inner surface of the hole  2   a  of the body  2 . Accordingly, the sliding movement of the jaws  3  is smoothly performed. Accordingly, it is possible to perform the hold of the tool  4  in a good manner. In particular, the vibration is applied intermittently in the axial direction or the rotational direction to a so-called hammer drill, a vibration drill, a driver drill or the like for applying the vibration or shock. A sticking is generated in the inner surfaces of the jaws  3  and the hole  2   a  during vibration and in some case, the sliding opening and closing operation of the jaws  3  is not well performed. Such a problem may be solved. 
   Incidentally, it is preferable to use as the coating layer such as “hard almite”, “Tahuramu” (Toughgram) Trade Mark made by Mitsubishi Material Company, or “RUBUNIKKU” (Lubnick) (Trade Mark made by Mitsubishi Material Company. Also, it is preferable that the thickness of the coating layer be in the range of 2 μm to 60 μm. Also, if the coating layer is applied also to the nut member  6  and the jaws  3 , the rotation of the nut member  6  is smoothly performed. 
   Embodiment 2 
     FIGS. 5 to 7  show a second embodiment of the invention, which will now be described. 
   In the second embodiment, the retainer spring member  7  of the first embodiment is composed of two retainer spring members  30  and  31 . A first retainer spring member  30  functions to retain with the ratchet teeth  5 . Also, the other retainer spring member  31  functions to hold the position of the rotary sleeve  1  to hold the first retainer spring  30  in a predetermined position. In the second embodiment, the retaining effect with the ratchet teeth  5  and the retaining condition holding effect and the retaining releasing condition holding effect with the ratchet teeth  5  are assigned to different springs, respectively, unlike the first embodiment. 
   Thus, in the second embodiment, since the retaining effect with the ratchet teeth  5  and the retaining condition holding effect and the retaining releasing condition holding effect with the ratchet teeth  5  are assigned to different springs, respectively, it is possible to suitably set the thickness of the other retaining spring member  31  to make it possible to select the retaining holding force. To such an extent, it is possible to easily set the retaining holding force as desired. The other structure is the same as that of the first embodiment. 
   Reference character  30 ′ denotes a portion corresponding to the tip end retainer portion  7 ′ of the first embodiment. Reference character  30   a  designates a portion corresponding to the projecting portion  7   a  of the first embodiment. Reference character  30   b  denotes a retaining portion corresponding to the projecting portion  7   b  of the first embodiment. Reference character  30   c  denotes a portion corresponding to the projecting portion  7   c  of the first embodiment. Reference character  30   d  denotes a retaining portion with the projecting portion  7   d.