Patent Document

CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of Provisional Application No. 60/488,146, filed on Jul. 16, 2003, the disclosure of which is hereby expressly incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to saw blade connectors and, more particularly, to saw blade connectors that are releasably attachable to hand-held tools.  
       BACKGROUND OF THE INVENTION  
       [0003]     Reciprocating saws, either manually or electrically operated, are used to cut a variety of materials, including stainless steel, wood, pipe, and conduits. Over time, the blade of such a saw, as with most other types of saw blades, become worn due to use and, therefore, must be replaced. As a result, most existing reciprocating saws include a feature that permits the saw blade to be replaced when worn.  
         [0004]     As noted above, reciprocating saws are either manually or electrically operated. In either case, when the saw blade is worn, it must be replaced. Currently, most manually operated hand-held reciprocating saws include a saw blade attachment apparatus having a pair of tines spaced to receive one end of the saw blade. The saw blade is fastened to the handle by a pin inserted transversely through the tines and through one end of the saw blade.  
         [0005]     In the case of electrically operated or powered hand tool, some existing designs have a fast change saw blade connector that are rotatably actuated between locked and unlocked positions. The designs of existing fast change connectors on the market are all intended to deal with the rapid forward and back motion of the electric powered reciprocating saws. These saws operate at speeds in excess of 3,000 strokes per minute. This rapid speed and directional change causes large inertial force on the blade connector. The momentum of the locking collar could overcome the locking aspect of the connector if the saw blade connector included a linearly actuated locking mechanism. Moreover, none of the existing connectors are known to include a supplemental restraint.  
         [0006]     Although such saw blade attachment apparatuses are effective at attaching a replaceable saw blade to a handle or machine, they are not without their problems.  
         [0007]     First, most currently available saw blade attachment apparatuses require the user to loosen a screw in order to remove or exchange saw blades and then retighten the screw before use. This requires the user to carry other tools, such as a screwdriver or hex key, for saw blade replacement. Additionally, because of the screw attachment, replacing saw blades is somewhat of a time-consuming task. Finally, although the saw blade is pinned within the blade attachment apparatus, it may rotate about the pin during use due to a worn interface between the saw blade and the saw blade attachment apparatus. This results in a potentially unsafe operating condition.  
         [0008]     Thus, there exists a need for a saw blade connector that provides rapid saw blade replacement and a more secure attachment of the saw blade to the hand tool.  
       SUMMARY OF THE INVENTION  
       [0009]     In accordance with one embodiment of the present invention, a saw blade connector for a hand tool is provided. The saw blade connector includes a shaft having a first end adapted to be releasably attached to a hand tool, and a lock mechanism. The lock mechanism is operatively coupled to the shaft for reciprocating movement between a locked position, where at least a portion of the lock mechanism engages a saw blade when the saw blade is coupled to the saw blade connector, and an unlocked position.  
         [0010]     In accordance with an aspect of another embodiment of the present invention, the lock mechanism includes a bearing member cooperatively disposed within the shaft and positioned for selective interference engagement with the saw blade to lock the saw blade within the saw blade connector when the lock mechanism is displaced into the locked position. In accordance with further aspects of yet another embodiment, the lock mechanism is configured to cooperate with a collar mounted on the shaft for reciprocating movement between the locked and unlocked positions. The collar includes a detent positioned to reciprocate the bearing member into and out of interference engagement with the saw blade.  
         [0011]     In accordance with other aspects of still yet another embodiment of the present invention, the saw blade connector includes an anchor coupled to the shaft and positioned to engage a portion of the saw blade when the saw blade is coupled to the saw blade connector. In accordance with yet other aspects of another embodiment, the anchor is a pin.  
         [0012]     A saw blade connector formed in accordance with the embodiments of the present invention has several advantages over currently available attachment assemblies. The lock mechanism provides for an easy and quick attachment assembly, thereby facilitating rapid blade replacement. Also, the first end of the shaft allows for the saw blade connector to be rapidly attached to a plurality of well-known tools. Finally, the anchor provides a supplemental restraint device to securely fasten the saw blade within the saw blade connector.  
         [0013]     Thus, a saw blade connector formed in accordance with embodiments of the present invention provides for quick interchangeability of replaceable saw blades, is adapted to be used with a plurality of existing tools, and provides an additional restraint anchor to securely fasten replaceable blades within the saw blade connector. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The foregoing aspects and many of the attendant advantages of this invention will become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0015]      FIG. 1  is a side planar view of a saw blade connector formed in accordance with one embodiment of the present invention;  
         [0016]      FIG. 2  is a side planar view of the saw blade connector of  FIG. 1 , shown as it would be used with a saw blade;  
         [0017]      FIG. 3  is an isometric, exploded view of the saw blade connector of  FIG. 1 , showing various components including a shaft and a lock mechanism;  
         [0018]      FIG. 4  is a side planar view of the saw blade connector of  FIG. 1 , partially cut away to show the saw blade connector in an unlocked position;  
         [0019]      FIG. 5  is a side planar view of the saw blade connector of  FIG. 1 , partially cut away to show the saw blade connector in a locked position; and  
         [0020]      FIG. 6  is a side planar view of the combination saw blade and saw blade connector of  FIG. 2 , partially cut away to show locking engagement of the saw blade connector with a saw blade and an anchoring aspect of the embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]     A saw blade connector  20  constructed in accordance with one embodiment of the present invention may be best understood by referring to  FIGS. 1-3 . The saw blade connector  20  is suitable for use with a well-known saw blade  22 , such as a reciprocating saw blade. Such saw blades  22  are designed for replacement when the saw blade  22  is worn.  
         [0022]     As may be best seen by referring to  FIG. 3 , the saw blade connector  20  includes a collar  30 , a locking and anchoring assembly  32 , and a shaft  34 . The shaft  34  is suitably a cylindrical member formed from a high strength material and includes first and second ends  36  and  38 .  
         [0023]     The first end  36  is formed as a hex shank and is commonly used for quick connection to a handle of a hand tool or a chuck of an electrically operated machine, such as a reciprocating saw. The first end  36  includes a detent groove  40  sized and configured for locking engagement with a correspondingly shaped and configured locking mechanism (not shown), such as a ball bearing.  
         [0024]     Although the shaft  34  is described and illustrated as including a hex shank first end  36  for replaceable attachment to a hand tool or a chuck, it should be apparent that the invention is not intended to be so limited. As a non-limiting example, the shaft  34  and, therefore, the resulting saw blade connector  20 , may be pressed fit or integrally formed with a handle for permanent attachment with a hand tool. As a result, such embodiments are also within the scope of the present invention.  
         [0025]     The second end  38  of the shaft  34  is suitably barrow-shaped and includes a slot  42  extending partially through a longitudinal direction of the shaft  34 . The slot  42  is sized and configured to receive one end of the saw blade  22 , as is described in greater detail below.  
         [0026]     The second end  38  also includes a lock mechanism bore  44  and an anchor bore  46 . Both the lock mechanism bore  44  and the anchor bore  46  extend substantially perpendicular to the longitudinal direction of the shaft  34 . The lock mechanism bore  44  and anchor bore  46  are sized to receive components of the locking and anchoring assembly  32 . In that regard, and as may be best seen by referring to  FIG. 4 , the lock mechanism bore  44  extends from an outside perimeter of the first end  38  through to the slot  42  and is sized to receive a lock mechanism  48  therein.  
         [0027]     As may be best seen by referring back to  FIG. 3 , the lock mechanism  48  includes a bearing member, such as ball bearings  50   a  and  50   b.  Although the bearing member is illustrated and described as being a pair of ball bearings  50   a  and  50   b,  other types of bearing members, such as a single ball bearing or a pin, are also within the scope of the present invention. It has been discovered by the inventors of the present invention that two ball bearings  50   a  and  50   b  are preferred in the present embodiment. Two ball bearings  50   a  and  50   b  are preferred as the reduced diameter of two ball bearings, as opposed to a single ball bearing, allows for a shorter travel of the lock mechanism as it is reciprocated between the locked and unlocked positions.  
         [0028]     The locking and anchoring assembly  32  also includes an anchor  52  sized to be received within the anchor bore  46 . The anchor  52 , as received within the anchor bore  46 , is positioned to lockingly engage a portion of the saw blade  22  when the saw blade is inserted within the slot  42  of the shaft  34 , as is described in greater detail below.  
         [0029]     Still referring to  FIG. 3 , the collar  30  is mounted on the shaft  34  for reciprocating movement of the saw blade connector  20  between locked and unlocked positions. The collar  30  is suitably mounted to the shaft  34  on a biasing member  54 , such as a coil compression spring. The biasing member  54  biases the collar  30  and, therefore, the saw blade connector  20  into the locked position, as seen in  FIG. 5 . The collar  30  is suitably locked to the shaft  34  by a well-known spring clip  56  sized to be lockingly received within a correspondingly shaped annular groove  58  formed in the shaft  34 .  
         [0030]     As may be best seen by referring to  FIGS. 4 and 5 , the collar  30  includes a detent  60  integrally formed within one end of the collar  30 . The detent  60  is positioned to reciprocate the bearing member  48  into and out of interference engagement with the saw blade  22 . The detent  60  includes a ramp  62  and a bearing cavity  64 . The ramp  62  and bearing cavity  64  both extend around the inside perimeter of one end of the collar  30 . The ramp  62  is adjacent the bearing cavity  64  and is positioned to assist reciprocating the bearing member  48  into and out of the locked and unlocked positions.  
         [0031]     Operation of the saw blade connector  20  may be best understood by referring to  FIGS. 4-6 . When the saw blade connector  20  is displaced into the unlocked position of  FIG. 4 , the first and second ball bearings  50   a  and  50   b  are free to be displaced upwardly into the bearing cavity  64 , such that an attachment end  70  of the saw blade  22  may be insertably received within the slot  42 . The attachment end  70  of the saw blade  22  include a tang  72  extending therefrom. As the saw blade  22  is inserted in the slot  42 , the tang  72  slides under the anchor  52  and the first and second ball bearings  50   a  and  50   b  are positioned adjacent a bore (not shown) extending through the attachment end  70  of the saw blade  22 .  
         [0032]     After the saw blade  22  is received within the slot  72 , the collar  30  is displaced into the locked position, assisted by the biasing member  54 . As seen in  FIGS. 5 and 6 , the collar  30  is displaced towards the first end  36  of the shaft  34  and into the locked position. As the collar  30  is displaced into the locked position, the ball bearings  50   a  and  50   b  are displaced within the lock mechanism bore  44  to at least partially seat the second ball bearing  50   b  within the bore extending through the attachment end  70  of the saw blade  22 .  
         [0033]     As received, the ball bearings  50   a  and  50   b  are placed into selective interference engagement with the saw blade  22  to lock the saw blade  22  within the saw blade connector  20 . Additionally, the anchor  52  engages the tang  72  to further assist in restraining the saw blade  22  within the saw blade connector  20 .  
         [0034]     To remove the saw blade  22  from within the saw blade connector  20 , the collar  30  is reciprocated into the unlocked position, thereby allowing the ball bearings  50   a  and  50   b  to retreat within the bearing cavity  64  and the saw blade  22  is then extracted from within the slot  42 .  
         [0035]     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

Technology Category: 7