Patent Application
20100219594
The invention relates generally to quick change holders and more particularly to a one-hand quick change holder.
Tool bit holders are known that typically consist of a member that has one end that is retained in the chuck of a hand or powered rotary tool such as a drill, power driver, screw driver or other rotary tool. The other end of the member supports a bit holder that releasably holds a tool bit such as a screw driver bit, drill bit or the like. The tool bit holder is retained in the chuck of the rotary tool such that the bits can be quickly inserted into the holder without having to manipulate the chuck. Tool bit holders are known to use a ball to retain a quick change style bit in the holder. These tool bit holders require two-hand removal of the bit and only work with quick change style bits.
The quick change tool bit holder comprises a hub defining a bore for receiving a bit. At least one retaining tooth is movable into engagement with the bit when the bit is inserted into the bore to retain the bit in the bore. An ejector ejects the bit from the bore when the retaining tooth is moved out of engagement with the bit. The ejector may comprise a spring that is compressed when the bit is inserted in the bore that biases a push button into engagement with the bit. A spring biased sleeve forces the retaining tooth into engagement with the bit when the sleeve is in the locking position. The tooth moves into engagement with the bit at an angle relative to the longitudinal axis of the bit. A method of operating the quick change tool bit holder is also disclosed.
Referring to the figures, the quick change holder of the invention 1 includes a central hub 2 having a shank 4 that is to be inserted into the chuck of a rotary tool such as a drill, screw driver, power driver or the like. The shank 4 has a plurality of flat faces 6 and an annular groove 8 that provide a quick change coupling with a standard chuck. Formed on the central hub 2 opposite to the shank 4 is a head 10 having an internal bore 12. The internal bore 12 comprises a first larger diameter bore 12a that opens to the end 46 of the head 10 opposite shank 4 and a second smaller diameter bore 12b that extends from the first bore 12a toward the shank 4. Larger diameter bore 12a may include a plurality of flat faces 13 that are coextensive with flat faces 29 on the tool bits to prevent relative rotation between the holder 1 and the tool bit. Typically, the faces 13 of bore 12a create a hex shaped bore. The bit is inserted into bore 12a along the longitudinal axis A-A with the longitudinal axis of the bit extending along the axis A-A.
Referring to
A sleeve 24 fits over head 10 such that it can reciprocate along the longitudinal axis A-A of the central hub 2. Sleeve 24 includes an internal bore 26 through which the central hub 2 extends. The internal bore 26 has a diameter that closely but slideably fits over flange 14. Further, an annular flange 28 extends from the interior wall 30 of bore 26 to closely but slideably receive the exterior face 32 of wall 20. The sliding engagement of flange 14 with internal bore 26 and the sliding engagement of flange 28 with wall 20 constrains the movement of the sleeve 24 to linear movement along axis A-A.
A compression spring 40 is located in the space 42 formed between the wall 20 and sleeve 24. The spring 40 engages shoulder 16 and flange 28 such that it biases the sleeve in the direction of arrow B to the locking position of
A retaining tooth 50 has one end loosely retained in aperture 52 formed on the sleeve 24. The opposite end of retaining tooth 50 extends into and through the aperture 18. Aperture 18 has camming surface 54 that is angled such that when the sleeve 24 is retracted in the direction opposite to arrow B the surface 54 moves retaining tooth 50 out of the large diameter bore 12a. Because the tooth 50 is loosely held in aperture 52, the tooth 50 can move slightly relative to the sleeve 24 to allow it to move out of the bore 12a. In the retracted position the retaining tooth 50 is flush with or slightly recessed from the internal surface of bore 12a. The bit is inserted into the bore 12a along the longitudinal axis A-A.
Each tooth has a generally L-shape including a first leg 51 connected to second leg 53. The first leg 51 is received in aperture 52 and the second leg 53 is received in aperture 18 and slides over camming surface 54.
A front collar 60 is fixed to the end of the central hub 4 to retain the sleeve 24 on the central hub. The collar 60 may be press fit onto the central hub or it may be secured by other attachment mechanisms such as welding, a mechanical fastener or the like. The front collar 60 has a camming surface 62 that extends over but spaced from the aperture 18. Camming surface 62 is arranged such that it forces retaining tooth 50 through aperture 18 and into bore 12a. The sleeve 24 forces the retaining tooth 50 into engagement with the bit when the sleeve is in the locking position. In one embodiment camming surface 62 is arranged substantially parallel to surface 54. The forward bias of the tooth 50 is guided downward into bore 12a by the angled camming surface 62 and the camming surface 54. The angled bias of the tooth 50 creates the force on the bit to hold the bit in the bore 12a. The surfaces 54 and 62 are arranged such that the tooth 50 is moved at an acute angle relative to the longitudinal axis A-A and the bit when the sleeve 24 forces the retaining tooth 50 into engagement with the bit.
The small diameter bore 12b retains an ejector 69 in the form of a push button 70 that is closely but slideably received in the bore 12b such that it can reciprocate along axis A-A. A compression spring 72 is trapped between the push button 70 and the end of bore 12b such that it biases the push button 70 to the extended position shown in
Referring to
To remove the bit, sleeve 24 is retracted against spring 40 in the direction of arrow C. As sleeve 24 retracts retaining tooth 50 is withdrawn from the bore 12a. Once the retaining tooth 50 is withdrawn from engagement with the quick connect coupler 25, spring 72 expands to force push button 70 against bit 23. Push button 70 ejects the bit 23 from the holder 1. Because the bit is ejected by simply retracting the sleeve 24, the quick change holder 1 can be operated by one hand to eject the bit. A magnet 80 may be located in the end of the push button as best shown in
Referring to
To remove the bit 21, sleeve 24 is retracted against spring 40 withdrawing retaining tooth 50 from engagement with the bit 21. Once the retaining tooth is withdrawn from engagement with the side of the insert bit 21, spring 72 expands to force push button 70 against bit 21. Push button 70 ejects the bit 21 from the holder 1. Because the bit is ejected by simply retracting the sleeve 24, the quick change holder 1 can be operated by one hand to eject the bit. A magnet 80 may be located in the end of the push button as best shown in
In the embodiment of
Like the previous embodiment, a front collar 60 is fixed to the end of the central hub 4 to retain the sleeve 24 on the central hub 2. The collar 60 may be press fit onto the central hub or it may be secured by other attachment mechanisms such as welding, a mechanical fastener or the like. The front collar 60 has camming surfaces 62 that extend over but are spaced from the apertures 18. Camming surfaces 62 are arranged such that they force retaining teeth 50 through apertures 18 and into bore 12a to engage and hold the bits as previously described. The teeth 50 are evenly spaced around hub 4 such that they are arranged at approximately 120 degrees from one another such that the holding force is exerted relatively evenly around the bit. The embodiment of
While embodiments of the invention are disclosed herein, various changes and modifications can be made without departing from the spirit and scope of the invention as set forth in the claims. One of ordinary skill in the art will recognize that the invention has other applications in other environments. Many embodiments are possible.
