Patent Publication Number: US-2010127463-A1

Title: Self-locking keyless drill chuck

Description:
TECHNICAL FIELD 
     The present invention relates to a drill chuck, in particular to a drill chuck installed on machining facilities and electric tools such as drilling machines and electric drills. 
     BACKGROUND TECHNOLOGY 
     In prior technology, a keyless drill chuck is provided with a drill body, three clamping jaws, a nut, a rotatable front sleeve and a rear sleeve. The front sleeve is axially positioned. Three clamping jaws are respectively arranged in three inclined holes which are evenly arranged on the drill body. A thread connection is adopted between the nut and the clamping jaws. The front sleeve is directly or indirectly connected with the nut. During operation, operating the front sleeve causes the nut to rotate, which in turn drives the clamping jaws to extend out of or retreat into the inclined holes, so that the drill chuck can clamp or loosen the drilling tool. These drill chucks have the disadvantages that, under the impact of an impulsive load, the drill bit clamped by the clamping jaws is easily loosened, slipped or even dropped. Thus, it is difficult to keep continuous operation. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a self-locking keyless drill chuck that is not easily loosened and slipped under the impact of an impulsive load. Therefore, the present invention adopts following technical solutions. The present invention comprises a drill body, three clamping jaws, a nut, a front sleeve and a rear sleeve. A thread connection is adopted between the clamping jaws and the nut. The rear sleeve is rotatably installed outside the drill body. The inner side of the front sleeve is provided with a ring gear at the rear part of the nut. A ring that cannot rotate relative to the drill body is arranged outside the drill body. The ring is provided with a member that cooperates with the gear and takes part in self-locking. The rear sleeve is provided with or in connection with an inner sleeve that rotates with the rear sleeve. The inner sleeve is provided with a structure engaging the member taking part in self-locking. Adopting this technical solution, the present invention has the advantages of more convenience in assembling. In addition, self-locking can be achieved through operating the rear sleeve. Accordingly, the drill bit clamped by the clamping jaws of the drill chuck is not easily loosened, slipped or dropped even under the impact of an impulsive load. 
    
    
     
       DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is an exterior view of the first and second embodiments of the present invention. 
         FIG. 2  is a sectional view of  FIG. 1  along the line A-A showing main internal structure of the drill chuck. 
         FIG. 3  is a sectional view of  FIG. 1  along the line B-B, where the first embodiment is adopted and the drill chuck is under a non-self-locking status. 
         FIG. 4  is a sectional view of  FIG. 1  along the line B-B, where the second embodiment is adopted and the drill chuck is under a self-locking status. 
         FIG. 5  is a sectional view of  FIG. 1  along the line C-C according to the first embodiment of the present invention. 
         FIG. 6  is an explosive view of the present invention according to the first embodiment. 
         FIG. 7  is a perspective view of the ring of the first embodiment of the present invention. 
         FIG. 8  is a perspective view of the inner sleeve of the first embodiment of the present invention. 
         FIG. 9  is a sectional view of  FIG. 1  along the line A-A, which shows main internal structure of the drill chuck according to the second embodiment of the present invention. 
         FIG. 10  is a sectional view of  FIG. 1  along the line B-B according to the second embodiment of the present invention, where the drill chuck is under a non-self-locking status. 
         FIG. 11  is a sectional view of  FIG. 1  along the line B-B according to the second embodiment of the invention where the drill chuck is under a self-locking status. 
         FIG. 12  is a sectional view of  FIG. 9  along the line E-E. 
         FIG. 13  is an explosive view of the second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The first embodiment of the present invention is shown in  FIGS. 1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 , and  8 . 
     The present invention comprises a drill body  1 , three clamping jaws  4 , a nut  3 , a front sleeve  2  and a rear sleeve  9 . A thread connection is adopted between the clamping jaws and the nut. The rear sleeve is rotatably installed outside the drill body. A collar  91  connects with the drill body. The collar is used for the positioning of the rear sleeve. The inner side of the front sleeve is provided with a ring gear  21  at the rear part of the nut. A ring  7  that cannot rotate relative to the drill body is installed outside the drill body. The ring is provided with a member that cooperates with the gear and takes part in self-locking. The member taking part in self-locking is a spring leaf  70 . The rear sleeve  9  is provided with or connected with an inner sleeve  8  that rotates with the rear sleeve. The inner sleeve is provided with a structure  80  acting on the member taking part in self-locking. In this embodiment, for balance, three spring leafs are circumferentially arranged along the ring. Correspondingly, three structures  80  engaging the member taking part in self-locking are circumferentially arranged along the inner sleeve. 
     The rear sleeve  9  and the inner sleeve  8  can be an integrated structure, an interference-fit structure, a key-slot combination or other connection modes, so that the rear sleeve  9  and the inner sleeve  8  can be connected and rotated together. The embodiment adopts the connection mode of a key-slot combination. Reference numeral  95  is the key in the rear sleeve and number  85  is the slot in the inner sleeve. 
     The self-locking is a mechanism that prevents the nut from loosening relative to the drill body along the retreating direction of the clamping jaws when the drill chuck is in operation. Using  FIG. 1  as an example, the downward direction is the direction that the clamping jaws advance, i.e., the front end direction of the drill chuck. The upward direction is the direction that the clamping jaws retreat, i.e., the rear end direction or the tail part direction of the drill chuck. 
     The spring leaf  70  comprises a lock end  71  in cooperated with the gear  21  and a protrusion  72  toward the direction of the drill body. The structure  80  which is arranged in the inner sleeve and engages the spring leaf  70  is arranged between the spring leaf and the drill body and is provided with a cam face cooperated with the protrusion  72 , so that the lock end  71  of the spring leaf  70  can be inserted into and separated from the gear  21 . The cam face comprises a concave surface  82 , which correspondingly controls the lock end  71  of the spring leaf  70  inserted into the gear  21 , and a concave surface  81 , which correspondingly controls the lock end  71  of the spring leaf  70  separated from the gear  21 . 
     The drill body is provided with a positioning structure according to the rotation position of the inner sleeve when the lock end of the spring leaf is being inserted into the gear. The positioning structure is the prismatic protrusion  12  on the surface of the drill body. The inner sleeve  8 , or the structure  80  that is arranged on the inner sleeve and acts on the spring leaf, is provided with another positioning structure cooperated with the prismatic protrusion  12 . Such another positioning structure is an inner concave  84 . This structure assists in providing a stable self-locking mechanism. The drill body is provided with a position-limiting structure that corresponds to the rotation limit of the inner sleeve where the lock end of the spring leaf separates from the gear. The position-limiting structure is the edge plane  11  on the surface of the drill body. The inner sleeve  8 , or the structure  80  which is arranged in the inner sleeve and acts on the spring leaf, is provided with a structure in cooperation with the edge plane  11 . The structure is the plane  83  in cooperation with the edge plane  11 . This arrangement prevents excessive rotation of the rear sleeve and the inner sleeve caused by misoperation as well as structural damages. 
     The ring  7  can be connected with the drill body in an interference-fit manner to rotate together with the drill body. In this embodiment, the ring  7  is positioned outside of the drill body. The ring  7  and the drill body are provided with a structure preventing their relative rotation. The structure is the edge plane  11  at the ring position and edge  73  inside the ring on the surface of the drill body. Their cooperation prevents relative rotation between the ring  7  and the drill body. Furthermore, the ring  7  is axially limited by the inner sleeve and the drill body. Therefore, the drill chuck has a simpler structure and is more convenient to assemble. 
     Referring to  FIG. 3  and  FIG. 4 , in this invention, looking from the tail part toward the rear end of the drill chuck, one can see that the section of the cam face cooperated with the protrusion controlling the lock end of the spring leaf to be inserted into the gear is at counterclockwise direction of the section controlling the lock end of the spring leaf to be separated from the gear. This facilitates the operation of the front sleeve and the rear sleeve. 
     Reference numeral  5  and numeral  6  represent a bearing and a washer between the nut and the drill body, respectively. Reference numeral  74  is a slug hole of the clamping jaws on the ring  7 . The front sleeve is connected with the nut. The rotation of the front sleeve can drive the nut to rotate and then make the clamping jaws advance or retreat, thereby clamping or loosening the drill bit. 
     During operation, as shown in  FIG. 3 , the lock end  71  is not inserted into the gear  21  and the drill chuck is at non-self-locking status. The plane  83  is propped against the edge plane  11 . Then a drill bit or other tools that need to be clamped are placed between the clamping jaws. The front sleeve  2  is rotated counterclockwise direction according to a view looking towards the paper surface. The nut is rotated to make the clamping jaws advance to clamp the drill bit. When the clamping jaws clamp the drill bit, the elastic force of the spring leaf  70  is overcome through continually inputting twisting force. The rear sleeve can rotate clockwise to reach the status of  FIG. 4 . Then, the protrusion  72  is engaged by the cam face to make the lock end  71  of the spring leaf inserted into the gear  21 . The front sleeve is continually rotated to input more twisting force. The gear  21  slips over the lock end  71  until the front sleeve cannot be rotated, thereby inputting twisting force to the utmost extent and increasing the clamping force upon the drill bit. At the status of  FIG. 4 , because the ring  7  cannot rotate relative to the drill body, and the lock end  71  is inserted into the gear  21 , even under the impact of an impulsive load, the nut will not easily counter-rotate relative to the drill body. This prevents the nut from loosening relative to the drill body along the direction that the clamping jaws retreating when the drill chuck is in use. Thus, the drill bit clamped by the clamping jaws cannot be easily loosened and slipped, thereby achieving self-locking. 
     When clamped tools need to be loosen after use, one can operate the drill chuck according to steps contrary to above steps. 
       FIGS. 1 ,  9 ,  10 ,  11 ,  12  and  13  demonstrate the second embodiments of the present invention. 
     In this embodiment, the inner sleeve  8  or the structure  80  which is arranged in the inner sleeve and engages the spring leaf is provided with a slot  86  to limit the rotation of the inner sleeve. The drill body is provided with a pin  92  in cooperation with the slot. The function achieved by the cooperation between the slot  86  and the pin  92  is the same as the function achieved by the cooperation between the plane  83  and the edge plane  11  and the cooperation between the prismatic protrusion  12  and the inner concave  84  in the first embodiment of the present invention. 
     Furthermore, the pin  92  can circumferentially position the ring  7 . As shown in  FIG. 9 , the pin  92  is extended from the step toward the rear end of the drill body. The ring  7  is provided with a circumferential positioning hole used for the insertion of the pin, so that the ring  7  can be positioned circumferentially. The ring  7  is axially limited by the inner sleeve and the drill body. In  FIG. 7 , reference numeral  13  is an installation hole of the pin  92 . 
     In this embodiment, the front end face of the nut  3  is connected with a plurality of planetary gear  33  which is arranged evenly along the circumferential direction of the nut. The axis of the planetary  32  is arranged on the nut. A center gear  14  meshing with the planetary gear is arranged on the drill body. The center gear  14  can be directly formed on the surface of the drill body or be produced into a ring part before being connected with the drill body. The inner side of the front sleeve is provided with a ring gear  22  meshing with the planetary gear. Reference numeral  31  is the sleeve of the nut, which is connected with two half bodies of the nut to form a complete nut  3 . 
     A front cover  34  is arranged at the front end of the drill chuck, which limits the front sleeve  2  and the planetary gear  33  axially at the front end. The front cover  34  itself is positioned by the collar  35  connected with the drill body. 
     During operation, when the front sleeve is rotated, the gear  22  drives the planetary gear  33  to move circumferentially on the surface of the center gear  14 , thereby driving the nut to move, which in turn causes the claws to clamp tools, and imputing more twisting force. Thus, the drill chuck can have a larger clamping force. 
     Other parts of the embodiment are the same as the first embodiment. The same reference numerals in  FIGS. 9 ,  10 ,  11 ,  12 ,  13  and  FIGS. 1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 ,  8  have the same meaning.