Abstract:
A saw blade retaining apparatus is provided for selectively retaining one in a series of saw blades having unique thicknesses. The retaining apparatus includes a rocker arm supported by a pair of lateral walls. The rocker arm includes a contoured contact surface which cooperates with a contoured stop segment extending between the lateral walls to securely retain one of a series of saw blades having unique thicknesses.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to clamp systems for saw blades, and more particularly to a clamp system able to secure any saw blade in a series of saw blades having various thicknesses.  
         BACKGROUND  
         [0002]    Clamp systems are incorporated in jig saws and other reciprocating saws to securely retain a shank portion of a saw blade during cutting. A conventional configuration of a clamp system includes the use of a retaining arm that interfaces with a hole or feature a certain distance from the end of the blade. To minimize cost on the clamping system, one retaining arm is implemented that has one optimum travel path having a limited tolerance for various blade thicknesses.  
           [0003]    It is common for a saw operator to require the use of a variety of saw thicknesses for a single project. Accordingly, the operator must switch blades for a given purpose. For example, a thin blade (0.030-0.039 inch) is needed for a fast cut or in cutting metal. A medium thickness blade (0.040-0.049 inch) is needed for general purpose cutting. A thick blade (&gt;0.049 inch) is needed for heavy duty purposes. The variety of blade thicknesses presents a problem for a clamping system unable to effectively adjust to the blade in use. Consequently, the retaining arm may be bottomed out and unable to effectively retain the shank of the saw blade. Additionally, blade wiggle can occur resulting in inconsistent cuts and overall poor performance.  
           [0004]    It is therefore desirable to provide a versatile clamping system that allows a variety of blades having a variety of thicknesses to be securely retained.  
         SUMMARY OF THE INVENTION  
         [0005]    It is a general object of the present invention to provide a saw blade clamp system that more effectively secures one of a series of saw blades having various thicknesses.  
           [0006]    In one form, the present invention provides a retaining apparatus for selectively retaining one of a series of saw blades. The apparatus includes a support structure including a pair of lateral walls and a base portion extending between the pair of lateral walls, a rocker arm having a first contact surface, the rocker arm supported between the pair of lateral walls; a stop having a second contact surface and disposed between the pair of lateral walls; wherein the rocker arm is operable toward a saw blade of the series of saw blades whereby the first contact surface interfaces with an aperture of the saw blade and the second contact surface interfaces with a trailing edge of the saw blade for securing the saw blade within the retaining apparatus.  
           [0007]    In another form, the present invention provides a retaining apparatus for selectively retaining one of a series of saw blades. The apparatus includes a support structure including a pair of lateral walls and a base portion extending between the pair of lateral walls, a rocker arm having a first contact surface and supported by the pair of lateral walls; a stop having a second contact surface and disposed between the pair of lateral walls; a first saw blade having an edge for communication with the stop and a mounting aperture for communication with the rocker arm, the mounting aperture disposed inboard a first predetermined distance from the edge and a second saw blade having an edge for communication with the stop and a mounting aperture for communication with the rocker arm, the mounting aperture disposed inboard a second predetermined distance from the edge, wherein the first predetermined distance is greater than the second predetermined distance and the second saw blade has a thickness greater than the first saw blade.  
           [0008]    In yet another form, the present invention provides a series of saw blades each including an elongated body having a blade end and a mounting end, the mounting end having an end edge and an aperture disposed therein. The series of saw blades includes a first blade having a first predetermined thickness and a first predetermined distance between the end edge and the aperture, and a second saw blade having a second predetermined thickness greater than the first predetermined thickness of the first blade and a distance between the end edge and the aperture that is less than the first predetermined distance.  
           [0009]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0011]    [0011]FIG. 1 is an environmental view of the saw blade retaining mechanism shown in a jig saw.  
         [0012]    [0012]FIG. 2 is a perspective view of the saw blade retaining mechanism.  
         [0013]    [0013]FIG. 3 is an exploded perspective view of the saw blade retaining mechanism.  
         [0014]    [0014]FIG. 4 is a plan view of the saw blade retaining mechanism.  
         [0015]    [0015]FIG. 5 is a side view of the saw blade retaining mechanism taken along line  5 - 5  of FIG. 4 shown operatively retaining a first or second saw blade having different thicknesses.  
         [0016]    [0016]FIG. 6 is a plan view of the saw blade retaining mechanism shown with the clamp system removed and a non canted blade positioned therein.  
         [0017]    [0017]FIG. 7 is a plan view of the saw blade retaining mechanism shown with the clamp system removed and a canted blade positioned therein.  
         [0018]    [0018]FIG. 8 is a plan view of the canted saw blade. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    With initial reference to the perspective view of FIG. 1, a retaining mechanism or clamp device  20  according to the teachings of the present invention is illustrated within a housing  11 . The housing  11  includes push button  8  which is operable to disengage the clamp device  20 . The clamp device  20  is shown operatively interconnected to a conventional jig saw  10  and is configured to securely retain a plurality of saw blades having a variety of thicknesses. For example, as shown in FIG. 5, the clamp device  20  is configured to securely retain a first or second blade  12 ,  12 ′ with different thicknesses.  
         [0020]    For exemplary purposes, blades  12  and  12 ′ are provided in the illustrations. Blade  12  has a thickness A of 0.035 inches (0.89 mm) and blade  12 ′ has a thickness A′ of 0.05 inches (1.27 mm). Blades  12  and  12 ′ generally fit the “thin” and “thick” blade categories respectively.  
         [0021]    With continued reference to FIG. 1, and additional reference to FIGS. 2 and 3 wherein the housing  11  and push button  8  have been removed for illustrative purposes, the retaining mechanism  20  generally includes a cam system  14  and base  16 . The cam system  14  includes a rocker arm  18  having a lever end  26 , an intermediate pivot portion  22  and a clamp end  24 . The intermediate pivot portion  22  is adapted to receive a support shaft  30  therethrough for rotational movement thereabout. The lever end  26  is activated by the push button  8  mounted on the housing  11 , shown in FIG. 1.  
         [0022]    Rocker arm  18  is biased in a clockwise direction (arrow C) such that the clamp end  24  is influenced against the saw blade  12 . Spring  32  includes a first and second end  34 ,  36  fixedly attached to a first and second side wall  40 ,  42  of base  16 . An intermediate loop  44  of the spring  32  is adapted to communicate with an upper surface  46  of the rocker arm  18  to provide a biasing force thereat.  
         [0023]    With particular reference to FIGS. 2 and 3, the base  16  includes a floor  50  having first and second side walls  40 ,  42  extending perpendicularly therefrom defining a channel  52 . The first and second side walls  40 ,  42  include first and second spring mounting passages  54 ,  56  for fixedly securing the spring ends  34 ,  36  therethrough. Similarly, support shaft  30  is retained through apertures  64 ,  66  disposed in walls  40 ,  42  respectively. The ends of first and second side walls  40 ,  42  are contoured outwardly creating first and second guide flanges  68 ,  70 . The guides  68 ,  70  serve to help direct the blade  12  into the channel  52 . The floor  50  of the base  16  includes a stop  72 . Stop  72  is oriented at an angle toward the cam system  14 .  
         [0024]    Referring now to FIGS. 2 and 3, the operation of the retaining mechanism  20  will now be described using saw blade  12 . To install blade  12  in the retaining mechanism  20 , the blade  12  is inserted through channel  52  against the clamp end  24  of cam system  14  until the outer edge  76  of the blade  12  abuts the angled contact surface  78  of stop  72 . Tail section  80  of blade  12  extends between stop  72  and the first side wall  40  to provide the blade  12  with additional stability. Side surface  74  of stop  72  provides a cutting bias against surface  58  of tail section  80  of blade  12 . Once the blade is fully inserted, spring  32  biases the contoured contact surface  82  of the clamp end  24  against the aperture wall  84  of the blade  12  thereby securing the blade  12  to the retaining mechanism  20 . Contoured contact surface  82  of clamp end  24  interfaces aperture wall  84  thus providing a secure edge contact therewith. Accordingly, the contoured contact surface  82  of clamp end  24 , the angled contact surface  78  and side surface  74  of stop  72  counter the forces created during cutting or other operations. To remove the blade, the push button  8  is pressed against the lever end  26  of rocker arm  18  to disengage the clamp end  24  from the aperture wall  84  of the blade  12 . Saw  10  prevents the user from turning on the unit while push button  8  is depressed. Similarly, push button  8  will not depress while saw  10  is in operation.  
         [0025]    Referencing FIGS. 2, 4 and  5 , the installation of second blade  12 ′ (which has a greater thickness A′ than thickness A of the first blade) is the same as described for the first blade  12 . The geometry of the angled contact surface  78  of stop  72  and the contoured contact surface  82  of rocker arm  18  is such that blades having different thicknesses may be securely retained. Explained further, blade  12  having a thickness “A” and a mounting aperture  86  a distance “B” from the outer edge  76  of the blade  12  is located securely between the contoured contact surface  82  of the clamp end  24  and the angled stop contact surface  78  at contact points  88 ,  90  respectively. Likewise, blade  12 ′ having a greater thickness, “A′” and a smaller distance “B′” from the outer edge of the saw may be securely retained in the clamp device  20  but has contact points  92 ,  94  located a distance higher on the respective clamp and stop contact surfaces  82 ,  78  respectively. As such, the geometry of the clamp contact surface  82  and the angled stop contact surface  78  cooperate to provide a versatile configuration that allows a variety of blades having a variety of thicknesses to be securely located at various contact points therebetween.  
         [0026]    Turning now to FIGS. 6, 7 and  8 , the retaining mechanism  20  of the present invention is operable to securely retain blade  12  which incorporates an integrated cant angle “a” (illustrated best in FIG. 8), as well as a blade  28  having no cant angle (FIG. 6). An important feature of canted blade  12  is that it includes a step  38  incorporated in the shank of the blade as well as an angled tail section  80 . The step  38  and angled tail section  80  of the blade shank design allows for a canted blade to be formed using standard manufacturing methods and using raw-material strips having the same widths “W” that apply to blades having no cant angle (as illustrated in FIGS. 6 and 8). As such, a canted blade can be provided for no additional cost compared to the zero canted blades. Explained further, edges  60 ,  62  of non-canted blade  28  are separated an equivalent distance (designated “W” on FIG. 6) as parallel edges  96 ,  98  of canted blade  12  (designated “W” on FIG. 8). Accordingly, canted blade  12  with step  38  and angled tail section  80  can be stamped from a material strip no wider than used for blade  28 . The angled tail section  80  of canted blade  12  includes a side surface  100  which is angled slightly relative to a longitudinal axis offset an angle “a” from the longitudinal axis “x” of the blade  12 . The mounting aperture  86  of the blade  12  is also angularly oriented such that the rear aperture wall  84  is perpendicular to the side surface  100  of the angled tail section  80  so that the aperture wall  84  is oriented perpendicular to the side walls  40 ,  42 . The outer edge  76  at the rear of the blade  12  is also perpendicular to the side surface  100 .  
         [0027]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.