Abstract:
A cutting tool clamp mechanism for a power tool includes a housing supported by a spindle, the spindle being configured to receive and drive a cutting tool along a longitudinal axis of the spindle. A clamping system is supported by the housing and includes an engaging portion movable relative to the spindle, the clamping system having an engaged condition, in which the engaging portion is engageable with the cutting tool to secure the cutting tool in the spindle, and a released condition, in which the engaging portion is disengageable with the cutting tool. A biasing member is positioned between the housing and the clamping system, and operable to bias the clamping system to the engaged condition. When the cutting tool is removed from the spindle, the clamping system is held in the released condition, and upon insertion of the cutting tool into the housing, the clamping system moves from the released condition to the engaged condition.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 60/972,457, entitled “BLADE CLAMP MECHANISM”, filed Sep. 14, 2007 by John S. Scott, the entire contents of which is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to reciprocating saws and more specifically to a blade clamp mechanism for quickly and easily replacing and securing a saw blade to a spindle of a reciprocating saw. 
         [0003]    Hand held reciprocating tools, such as electric reciprocating saws, include removable blades, which permit the use of different cutting edges as may be necessary for cutting different materials and for the replacement of worn or damaged blades. This requires a blade mounting system that allows rapid blade replacement while accurately and firmly coupling the blade to the tool. Typically, blade mounting systems require a tool, such as an Allen wrench or a special key, in order to replace and secure the blade, which is a slow and often difficult process. 
       SUMMARY 
       [0004]    The invention provides a cutting tool clamp mechanism for a power tool. The cutting tool clamp mechanism includes a housing supported by a spindle, the spindle being configured to receive and drive a cutting tool along a longitudinal axis of the spindle. A clamping system is supported by the housing and includes an engaging portion movable relative to the spindle, the clamping system having an engaged condition, in which the engaging portion is engageable with the cutting tool to secure the cutting tool in the spindle, and a released condition, in which the engaging portion is disengageable with the cutting tool. A biasing member is positioned between the housing and the clamping system, and operable to bias the clamping system to the engaged condition. When the cutting tool is removed from the spindle, the clamping system is held in the released condition, and upon insertion of the cutting tool into the housing, the clamping system moves from the released condition to the engaged condition. 
         [0005]    The invention provides a cutting tool clamp mechanism for a power tool. The cutting tool clamp mechanism includes a housing supported by a spindle, the spindle being configured to receive and drive a cutting tool along a longitudinal axis of the spindle. A clamping system is supported by the housing, the clamping system including an actuator portion movable relative to the spindle and an engaging portion configured to be moved by the actuator portion relative to the spindle. The clamping system has an engaged condition, in which the engaging portion is engageable with the cutting tool, and a released condition, in which the engaging portion is disengageable with the cutting tool. A biasing member is positioned between the housing and the clamping system, and operable to bias the clamping system to the engaged condition. An ejection system is positioned within the housing, the ejection system movable between an inserted condition and an ejected condition. When the clamping system is released from the engaged condition, the ejection system ejects the cutting tool from the housing and holds the clamping system in the released condition. 
         [0006]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a blade clamp mechanism according to an embodiment of the invention. 
           [0008]      FIG. 2  is an assembly view of the blade clamp mechanism in  FIG. 1 . 
           [0009]      FIG. 3  is a sectional view of the blade clamp mechanism taken along line  3 - 3  in  FIG. 1 , and showing the blade clamp mechanism in an engaged condition. 
           [0010]      FIG. 4  is a sectional view of the blade clamp mechanism showing the blade clamp mechanism in a released condition. 
           [0011]      FIG. 5  is a sectional view of the blade clamp mechanism showing the blade clamp mechanism in a no-blade condition. 
           [0012]      FIG. 6  is a sectional view of the blade clamp mechanism taken along line  6 - 6  in  FIG. 1 , and showing the blade clamp mechanism in the engaged condition. 
           [0013]      FIG. 7  is a sectional view of the blade clamp mechanism showing the blade clamp mechanism in the released condition. 
           [0014]      FIG. 8  is a sectional view of the blade clamp mechanism showing the blade clamp mechanism in the no-blade condition. 
       
    
    
       [0015]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
       DETAILED DESCRIPTION 
       [0016]      FIGS. 1-8  illustrate a tool clamp mechanism  10  for a power tool according to one embodiment of the invention. With reference to  FIG. 1 , the tool clamp mechanism  10  is mounted on a spindle  14  of a reciprocating saw (not shown), and is shown engaging a tool  18  (e.g., a saw blade) having a main portion  22  and a tang  26  ( FIGS. 2-4  and  6 - 8 ). In other embodiments, various reciprocating tools (e.g., saw blades) and/or rotating tools (e.g., drill bits) may be used with the blade clamp mechanism. 
         [0017]    The spindle  14  is adapted to be mounted for reciprocation within a body of the reciprocating saw along a longitudinal axis  16  of the spindle  14 . A drive portion (not shown) of the spindle  14  is adapted to be driven by a wobble plate or other mechanism (not shown), as is generally known in the art. The spindle  14  has an assembly seat  30  that includes an axially extending slot  34  (FIGS.  2  and  5 - 8 ) for receiving the tang  26  of the blade  18 , two generally planar surfaces  38  on the exterior of the assembly seat  30 , and an aperture  42  extending from one of the planar surfaces  38  to the slot  34 . 
         [0018]    The saw blade  18  includes two shoulder portions  50 A,  50 B ( FIGS. 1 and 2 ) that form a transition from the tang  26  to the main portion  22 . The saw blade  18  is able to be inserted into the spindle  14  in a first axial direction  52  and removed from the spindle  14  in a second axial direction  56  opposite of the first axial direction  52 . When the tang  26  of the saw blade  18  is inserted into the slot  34 , the shoulder portions  50 A,  50 B of the saw blade  18  engage the blade clamp mechanism  10  at two locations ( FIG. 1 ). The blade  18  further includes an aperture  54  ( FIGS. 2-4  and  6 - 8 ) to facilitate engagement of the blade  18  with the blade clamp mechanism  10 . 
         [0019]    The blade clamp mechanism  10  includes a housing  58  ( FIG. 1 ), a clamping system  62  for engaging and disengaging the saw blade  18 , and an ejection system  66  (FIGS.  2  and  6 - 8 ) for automatically ejecting the tool  18  from the blade clamp mechanism  10 . The housing  58  of the blade clamp mechanism  10  is adaptable to the assembly seat  30  of the spindle  14  and guided by the planar surfaces  38  of the assembly seat  30 . The housing  58  has two members  58 A,  58 B (i.e., a first member  58 A and a second member  58 B); however in other embodiments the housing  58  may be a single member or more than two members. In this embodiment, the two members  58 A,  58 B are generally mirror images of each other. The members  58 A,  58 B are located around the assembly seat  30  with the members  58 A,  58 B secured to one another by fasteners, such as bolts (not shown). In other embodiments, the members  58 A,  58 B may be secured by methods such as welding, clamping, snap rings and other fastening methods available to one skilled in the art. 
         [0020]    The assembled members  58 A,  58 B (i.e., housing  58 ) includes two chambers: a first chamber  70  ( FIGS. 2-5 ) for the clamping system  62  and a second chamber  74  (FIGS.  2  and  6 - 8 ) for the ejection system  66 . The first chamber  70  is defined by transverse surfaces  78  for guiding the clamping system  62  along a first transverse axis  82 , which is perpendicular to the longitudinal axis  16  of the spindle  14 . In the illustrated embodiment, the second member  58 B includes an aperture  90  for receiving the clamping system  62 . The aperture  90  extends through the second member  58 B from an exterior surface  102  of the housing  58  to the first chamber  70 . In other embodiments, the aperture  90  extends through the first member  58 A from the exterior surface  102  of the housing  58  to the first chamber  70 . The clamping system  62  slides within and protrudes from the second member  58 B in some positions. The second chamber  74  is defined by a first axial surface  84  and a second axial surface  86  opposite the first axial surface  84 , whereby the ejection system  66  slides between the first and second axial surfaces  84 ,  86 . 
         [0021]    The clamping system  62  includes an actuator portion  110 , an engaging portion  114  movable along a second transverse axis  116 , which is perpendicular to the first transverse axis  82  and to the longitudinal axis  16 , and two biasing members  118  for biasing the actuator portion  110 . In the illustrated embodiment, the actuator portion  110  is a user-actuated button, the engaging portion  114  is a detent ball and the biasing members  118  are springs (e.g., compression springs). In other embodiments, the actuator portion  110  is any device that may be actuated by a user, a robot and/or other mechanical devices known in the art. The actuator portion  110  includes a hub or tab  122  and an area or receptacle  126 , which has a generally keyhole shape that defines a cam surface  130  and two generally planar (cam) surfaces  134  ( FIGS. 2-5 ). In the illustrated embodiment, the actuator portion  110  moves along the first transverse axis  82  in a first transverse direction  144  and a second transverse direction  148  opposite the first transverse direction  144 . The actuator portion  110  engages and slides across the multiple transverse surfaces  78  of the first chamber  70  and the planar surfaces  38  of the spindle  14  to guide movement of the actuator portion  110  along the first transverse axis  82 . The actuator portion  110  also includes a pair of flanges  150  for capturing and compressing the two biasing members  118 . The flanges  150  of the actuator portion  110  reside within inner cavities  152  ( FIGS. 2-6 ) of the housing  58 . 
         [0022]    The engaging portion  114  includes a cam surface  154  (i.e., a spherical-shaped cam surface) for releasably engaging the actuator portion  110  and an engaging end  158  ( FIGS. 6-8 ) for sitting in the aperture  54  of the blade  18 . The cam surface  154  of the engaging portion  114  is positioned proximate the cam surfaces  130 ,  134  of the actuator portion  110  and may have various shapes, such as curved as shown in this embodiment. The engaging end  158  of the engaging portion  114  slides within the aperture  42  of the assembly seat  30  along the second transverse axis  116  to releasably sit within the aperture  54  of the blade tang  26 . The engaging portion  114  (i.e., the cam surface  154 ) slides against the cam surfaces  130 ,  134  when the engaging portion  114  is being removed from and inserted to the blade  18  such that the engaging end  158  disengages and engages with the blade  18 . 
         [0023]    Referring to  FIGS. 2-5 , each biasing member  118  includes a first leg  160  abutting the respective flange  150  and a second leg  164  positioned against a first wall  166  of the respective inner cavity  152 . The flanges  150  are locked against a second wall  168  of the cavities  152  by a biasing force of the biasing members  118 . The biasing members  118  are positioned to bias the engaging portion  114  of the clamping system  62  into the slot  34  to engage the blade  18 . 
         [0024]    The ejection system  66  includes an ejector  170 , or plunger, and a biasing member  174  (e.g., a spring). Referring to FIGS.  2  and  6 - 8 , the ejector  170  includes a collar or frame  176  and a hub  178 . An axial channel  186  of the spindle  14  intersects the slot  34  of the spindle  14  and receives the biasing member  174  and the hub  178 . The biasing member  174  resides in the channel  186  having a first leg  190  abutting a wall  194  ( FIGS. 6-8 ) of the spindle  14  and a second leg  198  abutting a surface  202  of the hub  178 . The biasing member  174  is positioned to bias the ejector  170  towards the blade  18  to eject the blade  18  from the slot  34  of the spindle  14  and therein the housing  58 . The frame  176  of the ejector  170  employs the second chamber  74  around the assembly seat  30 , such that the frame  176  moves axially, along the longitudinal axis  16  and between the axial surfaces  84 ,  86 , for engagement and disengagement with the blade  18 . 
         [0025]    The blade clamp mechanism  10  generally has three conditions: an engaged condition, a released condition and a no-blade condition. In the engaged condition ( FIGS. 3 and 6 ), the saw blade  18  is secured to the spindle  14  for synchronized movement therewith. The biasing member  118  biases the actuator portion  110  in the second transverse direction  148  such that cam surface  134  of the actuator portion  110  forces the engaging portion  114  toward the slot  34  to engage and secure the blade  18  with the spindle  14 . The tab  122  of the actuator portion  110  ( FIGS. 1 and 3 ) extends from the housing  58  and is accessible by a user. 
         [0026]    In the released condition ( FIGS. 4 and 7 ), the blade  18  is disengaged from the spindle  14  to allow removal of the blade  18  from the blade clamp mechanism  10 . The actuator portion  110  is pushed into the housing  58  ( FIG. 4 ), against the biasing force of the biasing members  118  to compress the biasing members  118  and remove the engaging portion  114  from the blade  18 . 
         [0027]    In the no-blade condition ( FIGS. 5 and 8 ), the saw blade  18  is removed from the spindle  14  and the housing  58 , and the engaging portion  114  engages the ejector  170 . The clamping system  62  is held in the released condition by the ejector  170  when the blade  18  is removed from the blade clamp mechanism  10 . 
         [0028]    The ejection system  66  generally has two conditions: an inserted or compressed condition and an ejected condition. In the inserted condition ( FIGS. 3 and 6 ), the blade  18  is engaged with the spindle  14  via the engaging portion  114 . The ejection system  66  is held in the inserted condition, against the biasing force of the biasing member  174 , by engagement of the clamping system  62  and the blade  18 . In the ejected condition ( FIGS. 5 and 8 ), the clamping system  62  is in the released condition to release the blade  18 , and the ejection system  66  ejects the blade  18  from the blade clamp mechanism  10 . The ejection system  66  is biased into the ejected condition by the biasing member  174 , because the clamping system  62  no longer holds the blade  18  in position, and the ejection system  66  holds the clamping system  62  (i.e., the engaging portion  114 ) in the released condition. In the ejected condition, the ejector  170  locks or prevents the engaging portion  114  from entering the slot  34 . 
         [0029]      FIGS. 3 and 6  illustrate the blade clamp mechanism  10  in the engaged condition. To release or remove the blade  18  from the spindle  14  of the blade clamp mechanism  10 , force is applied (generally by a user) to the tab  122  of the clamping system  62  in the first transverse direction  144 . The force compresses the biasing members  118  seated in the cavities  152  of the housing  58  and moves the actuator portion  110  in the first transverse direction  144  (i.e., the direction of the user applied force) relative to the housing  58  and the spindle  14 . The actuator portion  110  moves from the engaged condition ( FIGS. 3 and 6 ) toward the released condition ( FIGS. 4 and 7 ). Movement of the actuator portion  110  along the first transverse axis  82  causes the cam surface  154  of the engaging portion  114  to engage and slide against the cam surface  130  of the actuator portion  110 , which allows the engaging portion  114  to slide out of the blade aperture  54  along the second transverse axis  116 , and thereby disengage the engaging portion  114  from the blade  18 . Movement of the actuator portion  110  also disengages the planar surfaces  134  of the receptacle  126  from the planar surfaces  46  of the assembly seat  30 , which may be a partial disengagement or an entire separation. 
         [0030]    With the engaging portion  114  disengaged from the saw blade  18  ( FIGS. 4 and 7 ), the biasing member  174  biases the ejector  170  from the inserted condition ( FIGS. 3 and 6 ) toward the ejected condition ( FIGS. 5 and 8 ). The hub  178  of the ejector  170 , which is abutting the tang  26  of the blade  18 , slides in the second axial direction  56  through the channel  186  of the assembly seat  30 , thereby pushing the blade  18  in the second axial direction  56 . The force of the biasing member  174  forces the blade in the second axial direction  56 , which causes the engaging portion  114  to slide out of the aperture  42  as permitted by the cam surface  130  of the actuator portion  110 . The blade  18  slides out of the slot  34  via the hub  178  of the ejector  170 . As the blade  18  ejects from the spindle  14 , the engaging portion  114  slides across the tang  26  of the blade  18  (in the absence of the blade aperture  54 ) and because the biasing members  118  force the actuator portion  110  to the engaged condition, the engaging portion  114  engages a locking surface  206  (shown in  FIGS. 5 and 8 ) of hub  178 . 
         [0031]    At this point, the ejection system  66  is in the ejected condition and the blade clamp mechanism  10  is in the no-blade condition ( FIGS. 5 and 8 ). The biasing member  174  of the ejection system  66  forces the frame  176  to slide axially through the second chamber  74  and locks the hub  178  against a stop  208  of the assembly seat  30  protruding into the axial channel  186 . The stop  208  is positioned in the axial channel  186  ( FIG. 5 ) and limits the travel of the ejector  170  through the axial channel  186 , but does not extend into the slot  34  that receives the blade  18 . The hub  178  rests across the spindle aperture  42 , taking the place of the tang  26  of the blade  18  and prevents the engaging portion  114  from passing through the slot  34 . The engaging portion  114  is locked against the locking surface  206  of the ejector  170 , against the biasing force of the biasing members  118 , which causes the clamping system  62  to be held in the released condition ( FIGS. 5 and 8 ). Thus, the biasing members  118  ( FIG. 5 ) are held or compressed against the biasing force due to the engagement of the hub  178  and the engaging portion  114 . 
         [0032]    To insert the blade  18  into the spindle  14 , the tang  26  is pushed against the hub  178  of the ejection system  66 , which compresses and opposes the biasing force of the biasing member  174 . As the hub  178  is pushed axially toward the biasing member  174 , the biasing members  118  of the clamping system  62  (shown in  FIGS. 3-6 ) bias the actuator portion  110  and the engaging portion  114  in the second transverse direction  148 . The engaging portion  114  slides across the locking surface  206  of the ejector hub  178  and then the tang  26  until the aperture  54  of the tang  26  aligns with the engaging portion  114 . The alignment of the tang aperture  54  and the engaging portion  114  permits the engaging portion  114  to engage the blade  18  (the engaged condition shown in  FIGS. 3 and 6 ). One of the planar surfaces  134  of the actuator portion  110  engages the cam surface  154  of the engaging portion  114 , and the force of the biasing members  118  causes the engaging portion  114  to automatically sit in the aperture  54  of the tang  26 , locking the blade  18  into the blade clamp mechanism  10 . The biasing members  118  move the actuator portion  110  in the second transverse direction  148  to return the actuator portion  110  to the engaged condition ( FIGS. 1 ,  3  and  6 ) and ready the power tool for use. As shown in  FIG. 7 , the ejector  170  is locked in the channel  186  of the assembly seat  30  between the tang  26  and the biasing member  174  (i.e., in the inserted condition) to restrain the biasing force of the biasing member  174 . Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.