Patent Document

FIELD 
       [0001]    The present invention generally relates to saws. More specifically, the present invention is concerned with an assembly allowing a reciprocating saw blade to be operatively mounted on a rotating shaft, for example on the rotating shaft of a conventional table saw. 
       BACKGROUND 
       [0002]    Various devices have been designed to cut melamine-type covered panels (hereinafter “melamine panels”) on a table saw without chipping the edges of the cut on either side of the melamine panel, which normally occurs when the teeth of the saw blade exit the cut. 
         [0003]    While these devices may deliver adequate quality cuts, they have proved costly and difficult to adjust, in particular when the blades need resharpening. 
         [0004]    On the other hand, conventional reciprocating saws, which are less expensive to manufacture and operate than for example circular saw blades, are currently unusable to cut melamine since they cause the above-mentioned chipping of the edges. 
       SUMMARY 
       [0005]    An object is to provide an assembly for operating a reciprocating saw blade through a rotary shaft, for example on the rotating shaft of a conventional table saw. 
         [0006]    The problem of chipping the edges of the cut on both sides of a melamine panel when using a reciprocating saw blade is solved by varying the angle of the blade depending upon both its position and moving direction relative to the panel so that when the blade teeth are entering a surface of the panel, the blade teeth are pushing the surface of the panel towards the interior thereof. 
         [0007]    In accordance with an illustrated embodiment, there is provided an assembly for operating a reciprocating saw blade through a rotating shaft of a table saw, the assembly comprising: 
         [0008]    first and second coupling elements for receiving the saw blade, wherein the first and second coupling elements are rotatably coupled to the rotating shaft of the table saw for rotation in unison therewith and at a same angular speed along respective different radii and paths; the assembly being mounted to a table of the table saw so that i) one of the first and second coupling elements which is furthermost away from the table is movable along a larger circle than the other coupling element and ii) lines intersecting both circular paths during rotation of the first and second coupling elements converge at a fixed position above the table; 
         [0009]    whereby, in operation, the reciprocating saw blade is caused by the rotating shaft to reciprocate relative to the table with an angle that varies with a reciprocating direction of the saw blade relative to the table; the angle remaining acute relative to a corresponding one of a top and bottom surfaces of the table towards which the blade moves. 
         [0010]    According to some embodiments, there is provided an assembly to mount a reciprocating saw blade to a rotating shaft, the assembly comprising: 
         [0011]    a first sprocket provided with a first offset pin; 
         [0012]    a second sprocket provided with a second and different offset pin; 
         [0013]    a flexible link interconnecting both the first and second sprockets; 
         [0014]    a saw blade holding assembly provided with a first circular mounting aperture and a second elongated mounting aperture; the first and second mounting apertures being respectively associated with the first and second offset pins; 
         [0015]    wherein a) a reciprocating saw blade is mountable to the now blade holding assembly; and b) rotational movement of the flexible link causes upstroke and downstroke movements of the saw blade holding assembly. 
         [0016]    Other objects, advantages and features of the present invention will become more apparent upon reading the following non restrictive description of illustrated embodiments thereof, given by way of example only with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    In the appended drawings: 
           [0018]      FIG. 1  is a schematic side elevation of an assembly for operating a reciprocating saw according to a first illustrative embodiment; 
           [0019]      FIGS. 2 to 8  illustrate the assembly of  FIG. 1  in operation; 
           [0020]      FIG. 9  is a schematic side elevation of an assembly for operating a reciprocating saw blade according to a second illustrative embodiment; 
           [0021]      FIG. 10  is a front elevation view of the assembly of  FIG. 9 ; and 
           [0022]      FIG. 11  is a top plan view of the assembly of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one”. Similarly, the word “another” may mean at least a second or more. 
         [0024]    As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “include” and “includes”) or “containing” (and any form of containing, such as “contain” and “contains”), are inclusive or open-ended and do not exclude additional, unrecited elements or process steps. 
         [0025]    The term “about” is used to indicate that a value includes an inherent variation of error for the device or the method being employed to determine the value. 
         [0026]    The expression “connected” should be construed herein and in the appended claims broadly so as to include any cooperative or passive association between mechanical parts or components. For example, such parts may be assembled together by direct coupling, or indirectly coupled using further parts. The coupling can also be remote, using for example a magnetic field or else. 
         [0027]    Other objects, advantages and features of the assembly to mount a reciprocating saw blade to a table saw will become more apparent upon reading of the following non-restrictive description of illustrative embodiments thereof, given by way of example only with reference to the accompanying drawings. 
         [0028]      FIG. 1  schematically illustrates an assembly  10  for operating a reciprocating saw blade  20  through a rotating shaft, such as the shaft (not shown) of a table saw (not shown), for example. 
         [0029]    The assembly  10  includes a first sprocket  22  provided with an offset mounting point in the form of a pin  24 , a second sprocket  26  having the same number of teeth as the first sprocket  22  and provided with a different offset mounting point in the form of a in  28  and a flexible link in the form of a timing type belt  30  interconnecting the first and second sprockets  22  and  26 . The first sprocket  22  is fixedly mounted to the rotating shaft so that both the first and second sprockets  22  and  26  are rotatably coupled to the rotating shaft for rotation in unison therewith. A sprocket support (not shown) is provided to rotatably receive both first and second sprockets  22  and  26 . 
         [0030]    According to another embodiment (not shown), the link  30  is replaced by a gear assembly that interconnects the first and second sprockets  22  and  26  for rotation in unison. 
         [0031]    A saw blade holding assembly  32  is mounted to both the pins  24  and  28  of the first and second wheels  22  and  26 . More specifically, the holding assembly  32  is pivotally mounted to the first pin  24 , for example via C-clips (not shown) and pivotally and slidably mounted to the second pin  28  also via C-clips (not shown). More specifically, a cylindrical aperture (not shown) of the holding assembly  32  is used to mount the assembly to the first wheel  22  and an elongated aperture  34  is used to mount the assembly to the second wheel  26 . 
         [0032]    The reciprocating saw blade  20  is mounted to the saw blade holding assembly  32  via two fasteners  36 . 
         [0033]    The first and second sprockets  22  and  26 , with their corresponding pins  24  and  28  respectively define first and second coupling elements for receiving the saw blade  20 . 
         [0034]    Both mounting pins  24  and  28  being offset from the rotation axis of their respective sprocket  22  and  26 , the rotation of the rotating shaft causes the pins  24  and  28  to move along circular paths at the same radial speed. The first pin  24  being more severely shifted away from the rotational axis of its sprocket  22 , the radius defined by its path (not shown) is greater than the radius defined by the path of the second pin  28 . 
         [0035]    According to another embodiment (not shown), the holding assembly  32  is omitted and the saw blade  20  is configured with rounded and elongated holes to be directly mounted to the first and second sprockets  22  and  26 . 
         [0036]    According to still another embodiment, the saw blade  20  or the holding assembly  32  includes two pins and the sprockets are provided with respective rounded and elongated apertures to receive the pins and to allow the pins to move along circular paths upon rotation of a rotating shaft operatively coupled to both sprockets as described hereinabove. 
         [0037]      FIG. 1  shows the assembly  10  mounted under the table  38  of a table saw and being in the process of cutting a melamine panel  40  moving in the direction of arrow  42 . The panel  40  has a first face  44  sliding against the table top  38  and a second face  46  opposite and parallel to the first face  44 . 
         [0038]    Other characteristics and features of the assembly  10  will become more apparent upon reading the following description of the operation thereof, with references to  FIGS. 1 to 8 . 
         [0039]    As can be seen from  FIG. 1 , both wheels rotate counterclockwise (see arrows  48 ) at the same angular speed. 
         [0040]      FIG. 2  shows the assembly  10  when one eighth of a full rotation has been done. Since the holding assembly  32  is pivotally mounted to wheel  22 , rotation of said wheel  22  causes a downward movement of the blade  20  (see arrow  50 ). Since the offset of pin  24  is more severe than the offset of pin  28 , the saw blade  20  is angled towards the uncut portion of the panel  40  while it goes down. This angle of the blade  20  ensures that the teeth  21  thereof are only in contact with the second face  46  of the panel and do not contact the first face  44  during the downstroke. 
         [0041]      FIG. 3  illustrates the assembly  10  when one quarter of a full rotation has been done. When the assembly is in this position, the angle  60  between the longitudinal axis of the saw blade  20  and the vertical axis is near maximum. It will be appreciated to one skilled in the art that the intersection of both the vertical and the longitudinal axis of the saw blade  20  is at all time located about in the middle of the panel  40 . In other words, during rotation of the sprockets  22  and  26 , the line that intersects both pins  24  and  28  crosses at a fixed position regardless of the angular position of respective pins  24  and  28 . The saw blade  20  is so mounted to the assembly  10 , and the assembly  10  is so positioned relative the table  38  and, considering the predetermined thickness of the panel  40 , that the saw blade  20  contacts only one face of the panel  40  at any given time. 
         [0042]    In  FIG. 4 , three eights of a full rotation has been done and the blade  20  is getting close to the vertical. 
         [0043]    When half a turn has been done, as shown in  FIG. 5 , the saw blade  20  is vertical. As can be seen from this figure, the teeth  21  of the blade  20  do not contact either surfaces of the panel  40 . 
         [0044]      FIG. 6  illustrates the beginning of the upstroke of the saw blade  20  (see arrow  52 ). Again, since the offset of pin  24  is more severe than the offset of pin  28 , the saw blade  20  is angled away from the uncut portion of the panel  40  while it goes up. This angle of the blade  20  ensures that the teeth  21  thereof are only in contact with the first face  44  of the panel and do not contact the second face  46  during the upstroke. 
         [0045]      FIGS. 7 and 8  complete the upstroke. 
         [0046]    The sequence of movements schematically illustrated in  FIGS. 1 to 8  are repeated for each rotation of the rotating shaft (not shown) to which the assembly is mounted until the panel  40  has been cut. During a full rotation of the rotating shaft, the movement of the saw blade  20  is such that its teeth always touch faces  44  and  46  in a favorable moving direction, which is to push the panel faces towards the interior thereof. 
         [0047]    One skilled in the art will understand that the saw blade extends from the table with an angle that varies according to the reciprocating direction of the saw blade, so that the angle remains acute relative to a corresponding one of a top and bottom surfaces of the table towards which the blade moves, i.e. the second face  46  during the downstroke and the first face  44  during the upstroke. This results in the surface layers on both sides of the melamine panel being cleanly cut without being chipped. 
         [0048]    One skilled in the art will understand that the mounting means used to mount the reciprocating saw blade  20  to the mounting assembly  32 , such as the fasteners  36 , could be different depending upon the type of reciprocating saw blade used. 
         [0049]    Many saw blade tooth geometry can be used. As a non-limiting example, the reciprocating saw blade commercialized by the company Bosch, under model number T234X has been found adequate. 
         [0050]    Turning now to  FIGS. 9 to 11  of the appended drawings, an assembly  108  for operating a reciprocating saw blade  118  through rotating shaft  106  of a table saw  100  according to a second illustrative embodiment be described. 
         [0051]    The table saw  100  includes a table top  102 , a table saw shaft  106 , reversely driving sprockets  120 ,  122 , and  132 , and a stabilizing spring type bracket  104 . 
         [0052]    The assembly  108  to operate a reciprocating saw blade through a rotating shaft  106  includes a frame  110 , a driving sprocket  112  mounted on the table saw shaft  106 , idler sprockets  114  and  116 , a reciprocating saw blade  118  mounted to an assembly similar to the one described with reference to  FIGS. 1 to 8 , i.e. including first and second sprockets  120 ,  122  supporting a blade holder  124  via respective pins  126  and  128 . A counterbalancing saw blade  130  is mounted opposite the cutting saw blade  118  via the first and a third sprockets  120  and  132  via a blade holder  134  mounted to respective pins  136  and  138  thereof. A flexible link such as a double sided timing type belt  140  interconnects the various sprockets. 
         [0053]    One skilled in the art will understand that the assembly  108  operates as described hereinabove with reference to  FIGS. 1 to 8 . However, the purpose of the counterbalancing blade  130  is to minimize the vibration potentially caused by the upstroke/downstroke movements of the cutting blade  118 . 
         [0054]    As is apparent from  FIG. 10 , the blade holders  124  and  134  respectively supporting the saw blades  118  and  130  are positioned on either sides of the sprocket  120  to prevent interference therebetween. 
         [0055]    Also from  FIG. 10 , the frame  110  includes sidewalls with apertures designed to mount the various sprockets thereto. 
         [0056]    According to another embodiment (not shown), the second saw blade  130  is replaced by another element that counterbalances the first saw blade during operation thereof. 
         [0057]    It is to be noted that while the offset attaching points are described hereinabove as pins, other element(s) could be used to mount the saw blade holding assembly to the first and second sprockets while allowing the required pivoting movements therebetween. 
         [0058]    One skilled in the art will understand that by using disposable reciprocating saw blades, the user does not have to worry any longer about non negligible resharpening costs as well as cumbersome reinstallation and alignment techniques associated with the use of conventional and well known dual circular scoring saw blade system. 
         [0059]    Also, one skilled in the art will appreciate that some of the safety components required in conventional table saws, such as and without limitations, a splitter guard, are irrelevant for a table saw equipped with a reciprocating saw blade as described herein. 
         [0060]    Also, the above described assemblies to operate a reciprocating saw blade through rotating shaft are not limited to being used to cut melamine panels only. 
         [0061]    It is also to be noted that while the above description and the appended drawings are concerned with mounting a reciprocating saw blade to a table saw, the assembly described herein could also very well be used as an alternative to a band saw, primarily in view of the fact that it would permit cuts in stocks of almost limitless dimension sizes. 
         [0062]    It is to be understood that the assembly to mount a reciprocating saw blade to a rotating shaft is not limited in its application to the details of construction and parts illustrated in the accompanying drawings and described hereinabove. The assembly to mount a reciprocating saw blade to a rotating shaft is capable of other embodiments and of being practiced in various ways. It is also to be understood that the phraseology or terminology used herein is for the purpose of description and not limitation. Hence, although the assembly to mount a reciprocating saw blade to a rotating shaft has been described hereinabove by way of illustrative embodiments thereof, it can be modified, without departing from the spirit, scope and nature of the subject invention.

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