Abstract:
A clamping structure for a handled tool comprising: (1) a chuck body, provided with gear teeth, ratchet and guiding holes, (2) a plurality of grippers, mounted in the guiding holes of the chuck body and having partial thread on one end; (3) an inner gear ring, (4) a control outer sleeve, having a plurality of control keys and a plurality of driving keys thereon, (5) a driving member having inner taper thread and a plurality of pinions thereon, wherein the inner taper thread engages with the threads of the grippers, and the pinions, mounted to the driving member through pin shafts, engage with both the inner gear ring and the gear teeth of the chuck body, (6) a plurality of resilient anti-loose members with pawl. While the outer sleeve is rotated, its driving keys drive the inner gear ring rotating, which further causes the pinions, which engages with the inner gear, driving the driving member rotating around the chuck body. Sequentially, the greater force, produced by the gear transmission and the screw transmission between the driving member and the grippers, drives grippers clamping the tool handle. Simultaneously, under the control of the control keys, the pawls of the resilient anti-loose members engage with the ratchet of the chuck body, accordingly the tool handle is prevented from loosening off under the operating condition of striking.

Description:
[0001]     This application claims the benefit of the Chinese patent application No. 200510074581.4 filed on May 29, 2005, which is hereby incorporated by reference.  
       TECHNICAL FIELD  
       [0002]     The present invention relates to a clamping structure for a handled tool, more particularly to the clamping structure for a handled tool that may clamp the tool handle at a larger force with a planet mechanism.  
       BACKGROUND ART  
       [0003]     Generally, the existing clamping structure for a handled tool comprises a chuck body, grippers, nuts, bearings, an anti-loose device and an outer sleeve. The chuck body is connected to the driving spindle of the power device. The three grippers are mounted in three equally arranged guiding holes of the chuck body respectively. The grippers, provided with threads, produces screw transmission with the nuts. Rotating the outer sleeve connected to the nut will drive the grippers move along the guiding holes relatively to the chuck body resulting in the tool handle clamped or unclamped. The anti-loose device can prevent the handle from loosening off from the grippers when the tool is loaded and vibrated.  
         [0004]     In above structure, because of the very large contact stress produced by the threads between the grippers and the nut under operating load, the relatively sliding friction is large, accordingly the clamping force for clamping the tool handle, produced by the screw transmission between the nut and grippers, is difficult to be large enough, which results in that the grippers are incapable of clamping tightly the tool handle under the operating condition of heavy load and vibration. In addition, for those published anti-loose structures, the anti-loose effects are not good enough because of the structure limitation. For instance, in PCT/CN02/00375, there is a hidden trouble of looseness in the structure under the operating condition of vibration and strike.  
       SUMMARY OF THE INVENTION  
       [0005]     One object of the present invention is: By rotating the control outer sleeve with hand, one can drive an inner gear ring rotating. Larger rotative moment can then be produced by the transmission from a gear ring, through pinions, to a center gear of the chuck body, when resistance exists. That will result in that the tool handle can be clamped with stronger force, when the driving member is rotating relatively to the chuck body, namely, the thread, between the nut and the grippers, makes the relative rotation pushing the grippers to move along the guiding hole of the chuck body.  
         [0006]     Another object of the present invention is: during the clamping process of the tool handle mentioned above, the pawl portion of the anti-loose member engages with the ratchet gear when the grippers receive the counterforce of the tool handle. As rotating the outer sleeve with greater force makes grippers clamping the tool handle, the pawl portions make a resilient movement relatively to the ratchet gear and generate the consecutive click prompting the operator a sign of entering the process of clamping with larger force.  
         [0007]     Further object of the present invention is: when the grippers are clamping the tool handle under the operating condition of vibration and strike, because the pawl portions of the anti-loose members engage with the ratchet gear, which has the function of preventing the rotation in the opposite direction, the nut is prevented from rotating in the opposite direction relatively to the grippers, by the transmission from the inner gear ring through the pinion to the center gear of the chunk body. Consequently, the tool handle cannot loose off from the grippers under the operating condition of vibration and strike.  
         [0008]     The technique solution of the present invention is as follows.  
         [0009]     A clamping structure for a handled tool, mounted on a driving spindle driven by a power source, comprising: a chuck body connected at its rear end to the driving spindle, having an accommodating space therein for receiving the tool handle, and having a plurality of guiding holes equally distributed on the surface of a cone coaxial with the chuck body; a plurality of grippers connected with the chuck body and mounted in the guiding holes of the chuck body, with the rear end having partial thread and the front end used for clamping the tool handle ; a driving member mounted around the chuck body and provided with an inner taper thread for mating with the partial thread of the grippers; and a control outer sleeve, characterized in that further comprising: a center gear fixedly mounted to the chuck body; an inner gear ring mounted coaxially with the chuck body, connected with control outer sleeve and having inner gear teeth thereon; and at least one pinion, mounted to the driving member through a pin shaft and engaging with the inner gear ring and the center gear respectively.  
         [0010]     In detail, the clamping structure for a handled tool proposed in the present invention is generally mounted to a driving spindle driven by a power source and rotates in both directions driven by the driving spindle. The clamping structure comprises: a chuck body connected at its rear end to the driving spindle and a plurality of grippers connected to the chuck body, characterized in:  
         [0011]     (a) an accommodating space for receiving the tool handle formed at the front end of the chuck body,  
         [0012]     (b) a counter bore with length longer than that of the head of the screw connecting the chuck body to the driving spindle in the accommodating space,  
         [0013]     (c) a plurality of guiding holes equally distributed on the surface of the cone coaxial with the chuck body,  
         [0014]     (d) a support stand at an acute angle with the normal surface of the axis of the chuck body,  
         [0015]     (e) a plurality of connecting grooves at the rear portion of the chuck body,  
         [0016]     (f) a center gear integrated with the chuck body and a screw hole or a cone hole connected to the driving spindle at the rear end of the chuck body, and  
         [0017]     (g) The grippers, with partial thread on one end and approximate multi-prism on the other end for clamping the tool handle, are mounted in the guiding holes of the chuck body.  
         [0018]     The clamping structure further comprises:  
         [0019]     (1) an inner gear ring, mounted coaxially with the chuck body and having inner gear teeth, a plurality of partial pivot holes, a plurality of accommodating spaces for anti-loose member, a plurality of moving spaces for driving key and a positioning recess thereon;  
         [0020]     (2) a driving member, which is a rotatable composite structure, having force-transferring end face at an acute angle with the normal surface of its axis, inner taper thread, a plurality of pin shafts whose axes are parallel with those of the thread surface, and a plurality of pinions engaging with the inner gear ring and the center gear of the chuck body respectively and mounted to the pin shaft thereon;  
         [0021]     (3) a half-retainer bearing provided between the support stand of the chuck body and the force-transferring end face of the driving member and having a retainer and a plurality of rolling bodies thereon, wherein the retainer is an opening hollow truncated cone of which the generatrix line has a tilt angle with the plane of the rolling body equal to that of the support stand of the chuck body, and the inscribed circle radius of the rolling bodies in the non-operating direction, i.e., in radial direction, is larger than the inner radius of the retainer;  
         [0022]     (4) an axial positioning ring for positioning the driving member on the chuck body;  
         [0023]     (5) a plurality of resilient anti-loose members with a center pin associated therewith and mounted in the anti-loose member accommodating space of the inner gear ring, capable of swinging about the partial pivot hole, and having a pivot portion, a pawl portion, a projection portion and a support portion thereon, wherein the pivot portion and the center pin are the swinging center of the anti-loose member and the pawl portion engages with the ratchet gear under operating condition for preventing the driving member from counter-rotating relatively to the grippers;  
         [0024]     (6) a control outer sleeve, having striae on the external surface convenient of griping, a plurality of control keys, a plurality of connect keys, a plurality of driving keys thereon, wherein a projection portion is on the side of the driving key, the control key controls the pawl portion of the resilient anti-loose member engaging with the ratchet gear by pressing the projection portion of the resilient anti-loose member and the driving key is used for driving the inner gear ring rotating;  
         [0025]     (7) a retaining ring provided between the resilient anti-loose member and the pinion of the driving member;  
         [0026]     (8) a ratchet gear fixedly mounted to the connect teeth of the chuck body and having ratchets and a stop ring portion thereon, wherein the stop ring portion positions the control outer sleeve on the chuck body axially;  
         [0027]     (9) a front cover mounted around the chuck body and the front portion of the outer sleeve and having connecting grooves thereon, wherein the connecting grooves are connected to the connect keys of the control outer sleeve;  
         [0028]     (10) a rear cap mounted at the rear portion of the chuck body and having a hole connected to the rear portion of the chuck body and a plurality of connect keys thereon;  
         [0029]     (11) a plurality of antifriction units mounted between the chuck body and the control outer sleeve or between the driving member and the control outer sleeve and comprising an article made of low frictional coefficient materials (e.g., PTFE or graphite) and a retainer or comprising rolling bodies and a retainer.  
         [0030]     The object of the present invention can be further implemented as follows.  
         [0031]     The clamping structure for a handled tool proposed in the present invention is generally mounted on a driving spindle driven by a power source and rotates in both directions driven by the driving spindle. The clamping structure comprises a chuck body connected at its rear end with the driving spindle and a plurality of grippers connected to the chuck body, characterized in:  
         [0032]     (a) an accommodating space for receiving the tool handle formed at the front end of the chuck body;  
         [0033]     (b) a counter bore with length longer than that of the head of the screw connecting the chuck body to the driving spindle in the accommodating space,  
         [0034]     (c) a plurality of guiding holes equally distributed on the surface of the cone coaxial with the chuck body,  
         [0035]     (d) a support stand at an acute angle with the normal surface of the axis of the chuck body,  
         [0036]     (e) a plurality of connecting grooves at the rear portion of the chuck body,  
         [0037]     (f) an annular groove at the front portion of the chuck body,  
         [0038]     (g) a center gear integrated with the chuck body and a screw hole or a cone hole connected to the driving spindle at the rear portion of the clamping structure, and  
         [0039]     (h) The grippers with partial thread on one end and approximate multi-prism on the other end for clamping the tool handle are mounted in the guiding holes of the chuck body.  
         [0040]     The clamping structure further comprises:  
         [0041]     (1) an inner gear ring having inner gear teeth, a plurality of partial pivot holes, a plurality of accommodating spaces for anti-loose member, a plurality of moving spaces for driving key and a positioning recess thereon, and mounted coaxially with the chuck body;  
         [0042]     (2) a driving member, which is a rotatable composite structure, having force-transferring end face at an acute angle with the normal surface of its axis, inner taper thread, a ratchet gear integrated with the driving member, a plurality of pin shafts whose axis are parallel with those of the thread surface, and a plurality of pinions engaging with the inner gear ring and the center gear of the chuck body respectively and mounted to the pin shafts thereon;  
         [0043]     (3) a half-retainer bearing provided between the support stand of the chuck body and the force-transferring end face of the driving member, and having a retainer and a plurality of rolling bodies thereon, wherein the retainer is an opening hollow truncated cone of which the generatrix line has a tilt angle with the surface of the rolling body equal to that of the support stand of the chuck body and the inscribed circle radius of the rolling bodies in the non-operating direction, i.e., in radial direction, is larger than the inner radius of the retainer;  
         [0044]     (4) an axial positioning ring for positioning the driving member on the chuck body;  
         [0045]     (5) a plurality of resilient anti-loose members with a center pin associated therewith, mounted in the accommodating spaces for anti-loose member of the inner gear ring, capable of swinging about the partial pivot hole, and having a pivot portion, a pawl portion, a projection portion and a support portion thereon, wherein the pivot portion and the center pin are the swinging center of the anti-loose member and the pawl portion engages with the ratchets of the driving member under operating condition for preventing the driving member from counter rotating relatively to the grippers;  
         [0046]     (6) a control outer sleeve comprising an outer sleeve and a control ring, wherein the outer sleeve is provided with striae convenient of griping on its surface and the control ring is provided with longitudinal connect serration, a plurality of control keys, a plurality of driving keys thereon, wherein the connect serration is distributed circumferentially and used for fixedly connecting the control ring with the outer sleeve, a projection portion is on a side of the driving key and the control key controls the pawl portion of the resilient anti-loose member engaging to the ratchet gear by pressing the projection portion of the resilient anti-loose member, and the driving key is used for driving the inner gear ring rotating;  
         [0047]     (7) a retaining ring mounted between the resilient anti-loose members and the pinions of the driving member;  
         [0048]     (8) a clip ring mounted in the annular groove at the front portion of the chuck body and positioning the inner gear ring and the outer sleeve on the chuck body axially;  
         [0049]     (9) a rear cap mounted at the rear portion of the chuck body and having a hole connected to the rear portion of the chuck body and a plurality of connect keys thereon; and  
         [0050]     (10) a plurality of antifriction units mounted between the chuck body and the control outer sleeve or between the driving member and the control outer sleeve and comprising the articles made of low frictional coefficient materials (e.g., PTFE or graphite) and a retainer or comprising the rolling bodies and a retainer.  
         [0051]     The object of the present invention can be further realized as follows.  
         [0052]     The clamping structure for a handled tool, proposed in the present invention, is generally mounted on a driving spindle driven by a power source, and rotates in both directions driven by the driving spindle. The clamping structure comprises: a chuck body connected at its rear end with the driving spindle and a plurality of grippers connected to the chuck body, characterized in:  
         [0053]     (a) an accommodating space for clamping the tool handle is formed at the front end of the chuck body,  
         [0054]     (b) a counter bore with length larger than that of the head of the screw connecting the chuck body to the driving spindle in the accommodating space,  
         [0055]     (c) a plurality of guiding holes equally distributed on the surface of the cone coaxial with the chuck body,  
         [0056]     (d) a support stand, and  
         [0057]     (e) longitudinal connect teeth distributed around the external cylindrical surface of the chuck body, and  
         [0058]     (f) a screw hole or a cone hole connecting to the driving spindle at the rear portion of the clamping structure.  
         [0059]     The grippers, with partial thread on one end and the approximate multi-prism on the other end used for clamping the tool handle, are mounted in the guiding holes of the chuck body. The clamping structure is further provided with:  
         [0060]     (1) a center gear fixedly mounted on the connect serration of the chuck body,  
         [0061]     (2) a ratchet gear fixedly mounted on the connect serration of the chuck body as well,  
         [0062]     (3) an inner gear ring mounted coaxially with the chuck body and having inner gear teeth, a plurality of partial pivot holes, a plurality of accommodating spaces for anti-loose member, a plurality of moving spaces for driving key and positioning recesses thereon,  
         [0063]     (4) a driving member, which is a rotatable composite structure mounted on the chuck body, comprising a nut, a driving sleeve, a plurality of pin shafts and a plurality of pinions, wherein the nut is provided with taper thread, force-transferring end face and connect serration distributed around the external cylindrical surface, and the driving sleeve is fixedly mounted around the connect serration of the nut, and both the pin shaft and the driving sleeve are fixedly mounted on the circumference of the end face of the driving sleeve wherein the end face centers at the axis and the pin shaft is parallel with the axis of the driving sleeve, and the pinion mounted on the pin shaft engages with the inner gear ring and the center gear of the chuck body respectively,  
         [0064]     (5) a half-retainer bearing, provided between the support stand of the chuck body and the force-transferring end face of the driving member and having a retainer and a plurality of rolling bodies thereon, wherein the retainer is annular having rolling bodies thereon and the inscribed circle radius of the rolling body is larger than the inner radius of the retainer in the non-operating direction, i.e., in the radial direction,  
         [0065]     (6) a plurality of resilient anti-loose members with a center pin associated therewith, mounted in the anti-loose member accommodating space of the inner gear ring, capable of swinging about the partial pivot hole and having a pivot portion, a pawl portion, a projection portion and a support portion thereon, wherein the pivot portion and the center pin are the swinging center of the anti-loose member and the pawl portion engages with the ratchet gear connecting to the chuck body under operating condition for preventing the driving member from opposite rotating relatively to the grippers, (7) a control outer sleeve comprising an outer sleeve and a control ring, wherein the outer sleeve, provided with striae on its external surface for conveniently griping, is a sleeve-shaped member, having an annular connecting groove thereon, and the control ring is provided with connect serration, a plurality of control keys and a plurality of driving keys, wherein the connect serration is distributed at the outer circumference and used for fixedly connecting the control ring with the outer sleeve, a projection portion is on the side of the driving key, the control key controls the pawl portion of the resilient anti-loose member engaging to the ratchet gear by pressing the projection portion of the resilient anti-loose member and the driving key is used for driving the inner gear ring rotating,  
         [0066]     (8) a retaining ring provided between the resilient anti-loose member and the pinion of the driving member,  
         [0067]     (9) a rear cap mounted in the annular connecting groove of the outer sleeve and having a hole thereon for movably connecting with the rear portion of the chuck body,  
         [0068]     (10) a plurality of antifriction units mounted between the chuck body and the outer sleeve or between the driving member and the control outer sleeve and comprising an article made from low frictional coefficient materials (e.g., PTFE or graphite) and a retainer or comprising the rolling bodies and a retainer.  
         [0069]     (11) The connect teeth of the chuck body can be connect serration.  
         [0070]     Using the technique solutions mentioned above, this invention presents the following innovative effects:  
         [0071]     While rotating the control outer sleeve, the driving key driven by the outer sleeve makes the inner gear ring rotating. Then through the transmission from the gear ring, via the pinions of the driving member, to the center gear of the chuck body (or fixedly connected to the chuck body), the larger rotative moment is produced when resistance exists, which drives the driving member rotating relatively to the chuck body, i.e., drives the thread of the driving member (or nut) rotating relatively to the thread of the grippers. Sequentially the grippers are driven to clamp the tool handle with a larger force along the guiding hole of the chuck body.  
         [0072]     During the clamping process of the tool handle mentioned above, while the grippers receive the counterforce of the tool handle, the projection portion of the driving key on the control ring engages with the positioning recess of the inner gear ring, generating a click which prompts the operator a sign of starting clamping, simultaneously the pawl portion of the anti-loose member engages with the ratchet gear as well under the control of the control key.  
         [0073]     As continuing rotating the control outer sleeve resulting in that the grippers clamp the tool handle with larger force, the pawl portions of the anti-loose members make resilient movement relative to the ratchet gear generating the consecutive click which prompts the operator a sign of being in the process of clamping with larger force.  
         [0074]     While the grippers clamp the tool handle under the operating condition of vibration and strike, because the engagement between the pawl portion of the anti-loose member and the ratchet gear has the function of stopping the opposite rotation, the opposite rotation of the driving member (or nut) relative to the grippers is prevented by the transmission from the inner gear ring, via the pinion, to the center gear of the chuck body (or fixedly connected to the chuck body). Consequentially, the tool handle cannot be loosened off from the grippers under the operating condition of vibration and strike.  
         [0075]     When unclamping the tool handle, the control outer sleeve should be rotated in the opposite direction. The projection portion of the driving key engages with the other opposite positioning recess of the inner gear ring, generating a click which prompts the operator a sign of starting unclamping. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0076]     The above and other objectives and features of the present invention will become apparent from the following description of preferred embodiments, given in conjunction with the accompanying drawings, in which:  
         [0077]      FIG. 1  is a front sectional view of the clamping structure according to a first embodiment of the present invention;  
         [0078]      FIG. 2  is a sectional view taken along line D-D in  FIG. 1 , wherein the member  19  is removed;  
         [0079]      FIG. 3  is a sectional view taken along line J-J in  FIGS. 1 and 11 ;  
         [0080]      FIG. 4  is a sectional view taken along line H-H in  FIG. 3 ;  
         [0081]      FIG. 5  is a front sectional view of a half-retainer bearing in the claming structure according to the first embodiment and a second embodiment of the invention;  
         [0082]      FIG. 6  is a top view of  FIG. 5 ;  
         [0083]      FIG. 7  is a view of  FIG. 8  in direction D;  
         [0084]      FIG. 8  is a front sectional view of the clamping structure according to the second embodiment of the invention with the pin shafts ( 183 ,  363 ) and the pinion ( 184 ) being removed (a sectional view taken along line C-C in  FIG. 7 );  
         [0085]      FIG. 9  is a diagram view of the control ring ( 9 ) of the control outer sleeve ( 14 ) in the clamping structure according to the second embodiment of the present invention;  
         [0086]      FIG. 10  is a sectional view taken alone line B-B in  FIG. 9 ;  
         [0087]      FIG. 11  is a front sectional view of the clamping structure according to the second embodiment of the invention;  
         [0088]      FIG. 12  is a sectional view taken along line A-A in  FIG. 11 ;  
         [0089]      FIG. 13  is a front sectional view of the clamping structure according to the third embodiment of the invention;  
         [0090]      FIG. 14  is a sectional view taken along line F-F in  FIG. 13 , wherein the member  37  being removed;  
         [0091]      FIG. 15  is a sectional view taken along line G-G in  FIG. 13 . 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0092]     The clamping structure of the present invention can be used for clamping the tools with a handle with the primary function of producing rotating movement, for example drill, screw tap and so forth. For convenience, they are all called as the tool handle in this specification. The following is further description of the present invention associating with the figures.  
         [0093]     Referring to  FIG. 1  to  FIG. 6 , the clamping structure according to the first embodiment of the present invention comprises:  
         [0094]     a chuck body  1  including a screw hole or a cone hole  106  connected to the driving spindle  001  of the power source at its rear portion, a plurality of connecting grooves  107 , an accommodating space  101  in which the tool handle is clamped in its front end, a counter bore  102  in the accommodating space  101  with the length (L) larger than the length (e) of the head  002  of the screw connecting the chuck body to the driving spindle, a plurality of guiding holes  103  equally distributed on the surface of the cone coaxial with the chuck body, a support stand  104 , a center gear  105  integrally formed with the chuck body and the connect serration  108 ;  
         [0095]     a plurality of grippers  3  mounted in the guiding hole  103  of the chuck body  1  wherein the partial thread  301  is on one end and approximate multi-prism (multi-edges portion)  302  is on the other end, and used for clamping the tool handle;  
         [0096]     an inner gear ring  17  mounted coaxially with the chuck body I and having inner gear teeth  171 , partial pivot hole  172 , accommodating space  173  for anti-loose member, moving space  174  for driving key and positioning recesses  175  and  176 ;  
         [0097]     a driving member  18 , which is a rotatable composite structure, provided with the force-transferring end face  181  at an acute angle with the normal surface of its axis, inner taper thread  182 , a plurality of pin shafts  183  wherein the axis of the pin shaft is parallel with the axis of the thread face, a plurality of pinions  184  mounted to the pin shaft and engaging with the gear teeth  171  of the inner gear ring and the center gear  105  of the chuck body respectively;  
         [0098]     a ratchet gear  15  fixedly mounted to the connect serration  108  of the chuck body and having ratchets  151  and stop ring portion  152  thereon;  
         [0099]     a plurality of resilient anti-loose members  11  mounted in the accommodating space  173  for anti-loose member of the inner gear ring and capable of swinging about the partial pivot hole  172 , whereon are provided a pivot portion  112 , a center pin  115 , a pawl portion  111 , a projection portion  113  and a support portion  114 ;  
         [0100]     a half-retainer bearing  5  positioned between the support stand  104  of the chuck body and the force-transferring end face  181  of the driving member and having retainer  502  and a plurality of rolling bodies  501  thereon, wherein the retainer  502  is an opening hollow truncated cone of which the generatrix line has a tilt angleφwith the plane of the rolling bodies  501  equal to that of the support stand  104  of the chuck body, and the inscribed circle radius R 2  of the rolling bodies  501  in non-operating direction, i.e., in radial direction, is larger than the inner radius R 1  of the retainer;  
         [0101]     an axial positioning ring  121  positioning the driving member  18  on the chuck body  1 ;  
         [0102]     a control outer sleeve  14  having strias  145  convenient of griping on the external surface, a plurality of control keys  141 , a plurality of connect keys  144 , a plurality of driving keys  142  having projection portion  143  on its side;  
         [0103]     a retaining ring  19  mounted between the resilient anti-loose member  11  and the pinion  184  of the driving member;  
         [0104]     a front cover  16  mounted around the front portion of the chuck body  1  and the control outer sleeve  14 , having connecting groove  161  thereon and connecting to the connect key  144  of the control outer sleeve;  
         [0105]     an antifriction unit  13  comprising the articles  132  made of low frictional coefficient materials (e.g., PTFE or graphite) and a retainer  131  and mounted between the chuck body  1  and the control outer sleeve  14 ;  
         [0106]     a rear cap  2  mounted to the rear portion of the chuck body, and provided with a hole connecting to the rear portion of the chuck body and a plurality of connect keys  207 .  
         [0107]     Referring to  FIG. 7  to  FIG. 12 , the second embodiment of the present invention comprises:  
         [0108]     a chuck body  1  including a screw hole or a cone hole  106  connected to the driving spindle  001  of the power source at its rear portion, a plurality of connecting grooves  107 , an accommodating space  101  for clamping the tool handle in its front end, a counter bore  102  in the accommodating space  101  with the length (L) larger than the length (e) of the head  002  of the screw connecting the chuck body to the driving spindle, a plurality of guiding holes  103  equally distributed on the surface of the cone coaxial with the chuck body, a support stand  104 , center gear teeth  105  integrally formed with the chuck body;  
         [0109]     a plurality of grippers  3  mounted in the guiding hole  103  of the chuck body  1  wherein the partial thread  301  is on one end and approximate multi-prism  302  is on the other end, and used for clamping the tool handle;  
         [0110]     an inner gear ring  7  mounted coaxially with the chuck body  1  and having inner gear teeth  701 , partial pivot hole  702 , accommodating space  703  for anti-loose member, moving space  704  for driving key and positioning recess  705  thereon;  
         [0111]     a driving member  6 , which is a rotatable composite structure, provided with the force-transferring end face  601  at an acute angle with the normal surface of the axis of the driving member, inner taper thread  602 , a plurality of pin shafts  603  wherein the axis of the pin shaft is parallel with the axis of the thread face, a plurality of pinions  604  mounted to the pin shafts and engaging with the gear teeth  701  of the inner gear ring and the gear teeth  105  of the chuck body respectively, and the ratchet  605  provided on the external surface of the driving member;  
         [0112]     a plurality of resilient anti-loose members  11  mounted in the accommodating space  703  for anti-loose member of the inner gear ring and capable of swinging about the partial pivot hole  702 , whereon are provided pivot portion  112 , center pin  115 , pawl portion  111 , projection portion  113  and support portion  114 ;  
         [0113]     a half-retainer bearing  5  positioned between the support stand  104  of the chuck body and the force-transferring end face  601  of the driving member, having retainer  502  and a plurality of rolling bodies  501  thereon, wherein the retainer  502  is an opening hollow truncated cone of which the generatrix line has a tilt angleφwith the surface of the rolling bodies  501  equal to that of the support stand of the chuck body, and the inscribed circle radius R 2  of the rolling bodies  501  in non-operating direction, i.e., in radial direction, is larger than the inner radius R 1  of the retainer (referring to  FIG. 6 );  
         [0114]     an axial positioning ring  121  positioning the driving member  6  on the chuck body  1 ;  
         [0115]     a control outer sleeve comprising an outer sleeve  4  and a control ring  9 , wherein the outer sleeve has striae  405  on the surface convenient of griping and the control ring is provided with the longitudinal connect serration  904  circumferentially distributed and used for fixedly connecting to the outer sleeve  4 , a plurality of control keys  901 , a plurality of driving keys  902  having projection portions  903  and  904  on its side, wherein the control key controls the pawl portion of the resilient anti-loose member engaging with the ratchet gear by pressing the projection portion of the resilient anti-loose member, and the driving key drives the inner gear ring rotating.  
         [0116]     a retaining ring  69  mounted between the resilient anti-loose member  11  and the pinion  604  of the driving member;  
         [0117]     an antifriction unit  13  comprising the article  132  made of low frictional coefficient materials (e.g., PTFE or graphite) and a retainer  131  and mounted between the chuck body  1  and the outer sleeve  4 ; and  
         [0118]     a clip ring  122 , mounted in the front portion of the chuck body.  
         [0119]     Referring to  FIG. 13  to  FIG. 15 , a clamping structure according to the third embodiment of the present invention comprises:  
         [0120]     A chuck body  1  including a screw hole or a cone hole  106  connected to the driving spindle  001  of the power source at its rear portion, a plurality of connecting grooves  107 , an accommodating space  101  wherein the tool handle is clamped in the front end, a counter bore  102  in the accommodating space  101  with the length (L) larger than the length (e) of the head  002  of the screw connecting the chuck body to the driving spindle, a plurality of guiding holes  103  equally distributed on the surface of the cone coaxial with the chuck body, a support stand  104 , and connect serration  109  arranged annularly around the external cylindrical surface of the chuck body;  
         [0121]     a plurality of grippers  3  mounted in the guiding holes  103  of the chuck body  1  wherein the partial thread  301  is on one end and approximate multi-prism  302  is on the other end, and used for clamping the tool handle;  
         [0122]     a center gear  41  fixedly mounted to the connect serration  109  of the chuck body and having the gear teeth  415  thereon.  
         [0123]     an inner gear ring  27  mounted coaxially with the chuck body  1  and having inner gear teeth  271 , partial pivot hole  272 , accommodating space  273  for anti-loose member, moving space  274  for driving key and positioning recesses  275  and  276  thereon;  
         [0124]     a driving member, which is a rotatable composite structure mounted on the chuck body, comprising a nut  26 , a driving sleeve  36 , a plurality of pin shafts  363  and a plurality of pinions  364 , wherein the nut is provided with taper thread  262 , force-transferring end face  261  and connect serration  266  distributed around the external cylindrical surface, and the driving sleeve  36  is fixedly mounted around the connect serration  266  of the nut and both the pin shaft  363  and the driving sleeve are fixedly mounted on the circumference of the end face of the driving sleeve wherein the end face centers at the axis of the driving sleeve and the pin shaft is parallel with the axis of the driving sleeve, and the pinion  364  mounted to the pin shaft engages with the gear teeth  271  of the inner gear ring and the gear teeth  415  of the center gear of the chuck body respectively;  
         [0125]     a plurality of resilient anti-loose members  11  mounted in the accommodating space  703  for anti-loose member of the inner gear ring and capable of swinging about the partial pivot hole  702 , whereon are provided pivot portion  112 , center pin  115 , pawl portion  111 , projection portion  113  and support portion  114 ;  
         [0126]     a half-retainer bearing  15 , positioned between the support stand  104  of the chuck body and the force-transferring end face  261  of the driving member, having retainer and a plurality of rolling bodies thereon, wherein the retainer is annular having the rolling bodies thereon and the inscribed circle radius of the rolling bodies in non-operating direction, i.e., in radial direction, is larger than the inner radius of the retainer;  
         [0127]     a ratchet gear  51  fixedly mounted to the connect serration  109  of the chuck body and having ratchet  515  thereon;  
         [0128]     a control outer sleeve comprising an outer sleeve  34  and a control ring  39 , wherein the outer sleeve has striae  345  on the surface convenient of griping and the control ring is provided with the longitudinal connect serration  394 , a plurality of control keys  391  and a plurality of driving keys  392 , wherein the connect serration  394  is circumferentially distributed and used for fixedly connecting to the outer sleeve  34 , the driving key  392  has a projection portion  393  on the side, the control key controls the pawl portion  111  engaging with the ratchet gear  51  by pressing the projection portion  113  of the resilient anti-loose member and the driving key  392  drives the inner gear ring  27  rotating;  
         [0129]     a retaining ring  37  mounted between the resilient anti-loose member  11  and the pinion  364  of the driving member; and  
         [0130]     an antifriction member  40  made from low frictional coefficient materials (e.g., PTFE or graphite) and mounted between the chuck body  1  and the outer sleeve  34 .  
         [0131]     Now the operation of the clamping structure, according to the present invention, will be described with reference to the first embodiment.  
         [0132]     A tool handle  003  is inserted in the tool handle accommodating space  101  of the chuck body  1 , and then the control outer sleeve  14  is rotated relatively to the rear cap  2  mounted at the chuck body in the clamping direction. Driving keys  142  of the control outer sleeve  14  engage at their projection  143  with the positioning recess  176  of the inner gear ring  17  so that the inner gear ring  17  of the planet mechanism can be rotated relative to the chuck body  1 . In the planet mechanism, the pinions  184  engage simultaneously with the inner gear ring  17  and the ratchets  105  on the chuck body  1 , and rotate about chuck body  1 , therefore, the driving member  18  that the opinion  184  connected thereto may rotate relative to the chuck body  1 , so that the thread  182  of the driving member  18  is caused to rotate relative to the thread  301  of the grippers  3  mounted to the chuck body  1  so that the grippers  3  approach and clamp the tool handle  003 . With continually increasing the moment that rotates the control outer sleeve  14  relative to the rear cap  2  mounted on the chuck body  1 , the driving keys  142  move in the clamping direction leading their projection portions  143  engage with another positioning recesses  175 , which generates a click. At the same time the driving key  142  are in contact with the end wall of moving space  174  for driving key in the clamping direction, and the control keys  141  move and press the projection portion  113  of the resilient anti-loose member  11  such that the pawl portion  111  of the resilient anti-loose member  11  engage with the ratchets  151  of the ratchet gear  15 . Continually increasing the moment applied to cause the control outer sleeve  14  to rotate relative to the rear cap  2  mounted at the chuck body  1 , the driving keys  142  urge the inner gear ring  17  to move slightly, and the pawl  111  of the resilient anti-loose member  11  jumps along the ratchets  151  and generates consecutive click to prompt that the tool handle is now being clamped by the driving keys. Since the planet mechanism could have a very large gear ratio, the clamping structure may provide a larger clamping moment such that the jaws  3  may clamp the tool handle at a larger force.  
         [0133]     As it requires releasing the tool handle, the control outer sleeve  14  is rotated relative to the rear cap  2  in the contrary direction, and the control key  141  rotates in opposite direction to disengage from the projection portion  113  of the resilient anti-loose member  11 . Based on the action of the resilient force, the pawl portion  111  of the resilient anti-loose member  11  disengages from the ratchets  151 , at the same time, the projection  143  of the driving key  14  moves to engage with the other positioning recess  176  in opposite direction of the inner gear ring  17 , and generates the click prompting the operator a sign of beginning to loose.  
         [0134]     While the present invention has been described and illustrated herein with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention that come within the scope of the appended claims and their equivalents.