Patent Abstract:
There is provided a replaceable drywall saw blade capable of reciprocating in-line when mounted to a hand held reciprocating power saw. The blade includes a generally planar body member having a generally linear top edge and a generally parallel opposed bottom edge. The blade further includes a generally linear upper piercing edge angularly offset downwardly from the top edge. The blade additionally includes a generally linear lower piercing edge angularly offset upwardly from the bottom edge. The upper piercing edge and lower piercing edge intersect to form a forward point on said blade. A mounting aperture is also formed on the blade for releasably securing the blade to the hand held reciprocating power saw.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to Provisional Application No. 60/965,673 filed on Aug. 21, 2007 entitled Reciprocating Saw Blade, the entire contents of which is incorporated herein by reference. 
     
    
     STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
       [0002]    (Not Applicable) 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates generally to saw blades and more particularly, to a saw blade for use with a reciprocating saw for cutting drywall. 
         [0005]    2. Description of the Related Art 
         [0006]    Drywall is widely used in the construction industry for both residential and commercial construction. Sheets of drywall may be pre-fabricated at an off-site location and delivered to the construction site. The drywall sheets may be quickly and easily attached to the structural frame to form a wall, ceiling, or other surface. 
         [0007]    After the drywall is attached to the structural frame, it may be necessary to cut the drywall. For instance, an electrician may cut through the drywall to install recessed lighting in a ceiling. In addition, a plumber may cut through the drywall to access plumbing located behind the drywall. Various demolition projects may also require cutting or removal of certain sections of drywall. 
         [0008]    Conventional drywall cutting tools may be used to cut through the drywall. A typical drywall cutter includes a blade that is 4″-9″ in length. A common problem associated with usage of such drywall cutting tools is that when the blade is inserted into the drywall, the blade may cut or damage utilities located behind the drywall. For instance, the blade may cut or damage electrical lines, plumbing, or other utilities disposed behind the drywall. Contact between the blade and the utilities may also place the individual cutting the drywall at risk of injury (e.g. electrical lines, gas lines). In addition, such contact may also create considerable damage, which may be very costly to fix. In the case of a hired contractor, the cost of repair may be greater than the profit expected for the original project. 
         [0009]    Another problem associated with conventional drywall cutters relates to the dust generated when cutting the drywall. In particular, conventional drywall cutters tend to generate significant amounts of dust or debris when cutting the drywall. A standard sheet of drywall includes an inner chalky layer disposed between a pair of opposing outer paper-like layers. When the blade travels through the inner chalky layer, it has a propensity to pull chunks of the inner chalky layer out of the drywall sheet, which causes dust to settle in the areas surrounding the drywall. As such, the dusted areas typically require cleaning once the drywall is cut. The cleanup adds unwanted time and expense to the construction project. 
         [0010]    As is apparent from the foregoing, there exists a need in the art for a drywall cutting blade configured to mitigate contact with utilities disposed behind the drywall as well as to reduce the dust generated with cutting the drywall. The present invention addresses this particular need, as will be discussed in more detail below. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    According to an aspect of the present invention, there is provided a replaceable drywall saw blade capable of reciprocating in-line when mounted to a hand held reciprocating power saw. The blade includes a generally planar body member having a generally linear top edge and a generally parallel opposed bottom edge. The blade further includes a generally linear upper piercing edge angularly offset downwardly from the top edge. The blade additionally includes a generally linear lower piercing edge angularly offset upwardly from the bottom edge. The upper piercing edge and lower piercing edge intersect to form a forward point on said blade. The blade also includes a mounting aperture connected to the body member for releasably securing the blade to the hand held reciprocating power saw. 
         [0012]    The blade may be sized and configured to mitigate contact between the blade and utilities which may be disposed behind the drywall. In this manner, the blade may be configured to be inserted into the drywall, with a minimal amount of the blade being completely advanced therethrough. In addition, the blade may minimize the amount of dust generated during insertion and removal of the blade into and out of the drywall. In this regard, the at least one tooth may be configured to cut through an outer layer of the drywall to mitigate the amount of dust produced when cutting the drywall. 
         [0013]    The blade may include at least one saw tooth is formed in the bottom edge. The blade may further include an upper piercing edge and a lower piercing edge that intersect at a right angle. Furthermore, the blade may include a plurality of saw teeth. In addition, the thickness of the blade may be substantially uniform along its length. 
         [0014]    The present invention is best understood by reference to the following detailed description when read in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings in which like numbers refer to like parts throughout and in which: 
           [0016]      FIG. 1  is an upper perspective view of a blade for use with a reciprocating saw to cut drywall, the blade having a blade body, a blade tip, a pair of teeth, and an engagement element; 
           [0017]      FIG. 2  is a side elevation view of the blade illustrated in  FIG. 1 ; 
           [0018]      FIG. 3  is a side elevation view of the blade connected to a reciprocating saw to define a saw-blade assembly, with the blade positioned for insertion into a section of drywall, the drywall having a first outer layer and an opposing second outer layer with an inner layer disposed therebetween; 
           [0019]      FIG. 4  is a side elevation view of the saw-blade assembly illustrated in  FIG. 3 , with the blade advanced into the drywall; and 
           [0020]      FIG. 5  is a side elevation view of the saw-blade assembly illustrated in  FIG. 4 , with the blade removed from the drywall. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring now to the drawings wherein the showings are for purposes of illustrating a preferred embodiment of the present invention only, and not for purposes of limiting the same,  FIGS. 1-6  illustrate a drywall cutting blade  10  constructed in accordance with an embodiment of the present invention. Various aspects of the invention are directed toward a blade  10  configured to reduce the amount of dust produced when cutting the drywall  40 . Furthermore, other aspects of the invention are directed toward mitigating contact between the blade  10  and utilities which may be disposed behind the drywall  40 , such as plumbing and electrical lines. 
         [0022]    The blade  10  is configured for use with a reciprocating saw  12  for cutting drywall  40 . As used herein, a reciprocating saw  12  is a tool that is engageable with a cutting instrument (such as a blade  10 ) to drive the cutting instrument through a cutting cycle. In most cases, the reciprocating saw repeatedly pushes and pulls the blade  10  through a cutting material. It is understood that reciprocating saws  12  are commonly employed in construction and demolition projects. The size and shape of the reciprocating saw  12  may vary. Reciprocating saw  12  are readily available in handheld and cordless models, as well as high-speed, high-power corded models. An exemplary reciprocating saw  12  is the DeWalt Heavy-Duty 10.0 Amp Reciprocating Saw manufactured by DeWalt, headquartered in Baltimore, Md. 
         [0023]    Referring now specifically to  FIGS. 1 and 2 , the blade  10  includes a blade body member  14  defining a body leading portion  24  and a body engagement portion  26 . As used herein, the body engagement portion  26  refers to that portion of the blade body  14  that is disposed closest to the reciprocating saw  12  when the blade  10  is connected thereto. Furthermore, the leading portion  24  refers to that portion of the blade body  14  that is farthest from the saw  12  when the blade  10  is connected thereto. The body leading portion  24  is also that portion of the body member  14  that is initially inserted into the drywall  40 . 
         [0024]    The blade body  14  includes a body top edge  18  and an opposing body bottom edge  16 . The body top and bottom edges  18 ,  16  extend along the blade body  14  between the blade engagement portion  26  and the blade leading portion  24 . It may be desirable for the body top and bottom edges  18 ,  16  to be substantially planar to facilitate insertion and removal of the blade  10  from the drywall  40 . Furthermore, in one embodiment, the top and bottom edges  18 ,  16  are substantially parallel (as shown in  FIGS. 1 and 2 ). However, it is understood that the body top and bottom edges  18 ,  16  may also define a non-parallel configuration. Furthermore, it is understood that insertion and removal of blade  10  into and out of the drywall  40  may further be facilitated by smooth, planar body top and bottom edges  18 ,  26 . 
         [0025]    The blade  10  further includes a pair of opposing lateral surfaces  20  extending along the length of the blade  10 . The lateral surfaces  20  extend between the body top edge  18  and the body bottom edge  16 . The distance between the opposing lateral surfaces  20  defines a blade thickness “T.” In one embodiment, the blade thickness T is substantially uniform. For instance, in one particular embodiment, the blade thickness T is approximately 0.05 inches. However, the thickness T may vary without departing from the spirit and scope of the present invention. 
         [0026]    Given that the blade  10  is configured to cut drywall  40  through repeated insertion and removal of the blade  10  through the drywall  40 , it is desirable to form the blade body  14  out of a strong, durable material. In one particular embodiment, the blade body  14  is formed of steel. However, other materials known by those skilled in the art may also be used. 
         [0027]    The blade  10  includes a blade tip  28  for piercing through the drywall  40  upon insertion of the blade  10  into the drywall  40 . The blade tip  28  is connected to the body leading portion  24 . In one embodiment, the blade tip  28  is integrally formed with the blade body  14 . The blade tip  28  includes an upper piercing edge  30  connected to the body top edge  18  to define an upper tip angle α therebetween. The blade tip  28  further includes a lower piercing edge  32  connected to the body bottom edge  16  to define a lower tip angle φ therebetween. The upper piercing edge  30  and the lower piercing edge  32  intersect at a forward point  29  to define a primary tip angle θ. In one embodiment, and as depicted in the figures, the primary tip angle is 90 degrees. In other words, the upper piercing edge  30  is substantially orthogonal to the lower piercing edge  32 . Accordingly, the upper and lower tip angles α, φ are obtuse in nature. In this regard, the upper and lower tip angles α, φ are greater than 90 degrees but less than 180 degrees. 
         [0028]    The upper piercing edge  30  defines an upper piercing length “U,” defined as the distance between the forward point  29  and the intersection between the upper piercing edge  30  and the body top edge  18 . The lower piercing edge  32  defines a lower piercing length “P,” defined as the distance between the forward point  29  and the intersection between the lower piercing edge  32  and the body bottom edge  16 . According to various embodiments, the upper piercing length U and the lower piercing length P may vary. For instance, in one embodiment, the upper piercing length U is greater than the lower piercing length P. However, in another embodiment, the upper piercing length U is less than the lower piercing length P. Furthermore, in an additional embodiment, the upper piercing length U and the lower piercing length P are substantially identical. 
         [0029]    The blade tip  28  may be formed of strong durable material capable of penetrating through the drywall  40 . In one embodiment, at least a portion of the blade tip  28  is formed of a carbide material (e.g. tungsten carbide, titanium carbide). Carbide may be desirable because of its tendency to remain sharp after repeated use. In another embodiment, the blade tip  28  may be formed of steel or other materials known by those skilled in the art. In this manner, the blade tip  28  may be formed of the same or different material used to form the blade body  14 . 
         [0030]    According to one aspect of the invention, the blade  10  also includes one or more teeth  34  for cutting a portion of the drywall  40 . The teeth  34  are connected to the engagement portion  26  of the blade body member  14 . As shown in  FIGS. 1 and 2 , the blade  10  includes a pair of teeth  34  connected to the engagement portion  26  at the body bottom edge  16 . However, it is understood that the size, shape, and number of teeth  34  may vary. For instance, when cutting thicker pieces of drywall  40 , larger teeth  34  may be desirable. The interaction between the teeth  34  and the drywall  40  will be described in more detail below. 
         [0031]    The distance between the forward point  29  and the most rearward tooth  34  defines an operative blade length “L,” as depicted in  FIG. 2 . It is understood that utilities, including but not limited to, electrical wiring and plumbing may be disposed behind a sheet of drywall  40 . When the blade  10  is advanced through the drywall  40  for purposes of cutting the drywall  40 , there is a risk of contacting the utilities. Contact between the blade  10  and the utilities may damage the utilities as well as create a safety hazard. For instance, if the blade  10  contacts a live electrical wire, the user may be electrocuted. In addition, if a blade  10  punctures a plumbing line, the surrounding areas may become flooded. Consequently, considerable time and money may be expended to repair damage caused by inadvertent contact between the blade  10  and the utilities. Therefore, by minimizing the operative blade length L, contact between the blade  10  and utilities disposed behind the drywall  40  may be mitigated. It is understood that various embodiments of the present invention include a blade length L that is considerably less than conventional saw blades. In this manner, it is less likely that the blade  10  will contact utilities disposed behind the drywall  40 . It is also understood that the blade length L may vary according to the thickness of the drywall  40 . For instance, for thicker pieces of drywall  40 , a larger blade length L may be desired. 
         [0032]    The blade  10  additionally includes an engagement element  36  connected to the engagement portion  26  of the blade body member  14 . The engagement element  36  is sized and configured to be engageable with the reciprocating saw  12 . Many conventional reciprocating saws  12  engage with a blade  10  by way of a through-hole formed in the blade  10 . Accordingly, the embodiment illustrated in  FIGS. 1 and 2  includes a mounting aperture  38  for engagement with a reciprocating saw  12 . The mounting aperture  38  extends between the opposing lateral surfaces  20  of the blade  10 . It is understood that the engagement element  36  may take on other configurations without departing from the spirit and scope of the present invention. 
         [0033]    Referring now to  FIGS. 3-5 , there is illustrated a sequence of blade positions relative to a section of drywall  40  during operation of the blade  10 . The blade  10  is operable to cut drywall  40  upon repeated blade  10  insertion and removal into and out of the drywall  40 . Conventional drywall  40  includes a first outer layer  42  and an opposing second outer layer  44 . The first and second outer layers  42 ,  44  are generally formed from a paper-like material. The drywall  40  includes a drywall inner layer  46  disposed between the opposing first and second outer layers  42 ,  44 . The inner layer  46  typically includes a chalky material that tends to generate a substantial amount of dust as the blade  10  is advanced and removed therethrough. Conventional drywall  40  is typically manufactured in a number of standard thicknesses. The drywall thickness “D” is defined by the distance between the first outer layer  42  and the second outer layer  44 . Drywall  40  having a thickness of ¼ inch, ½ inch, or ⅝ inch, is commonly used in the construction industry. 
         [0034]      FIG. 3  depicts a blade-saw assembly  50  including a blade  10  connected to a reciprocating saw  12  having a saw guard  55 . The blade-saw assembly  50  is positioned to cut the drywall  40 . In this regard, the blade  10  is positioned to enter the drywall  40  through the first outer layer  42 . The blade  10  is inserted into the drywall  40  along an insertion axis  52 . According to one embodiment, the insertion axis  52  is substantially orthogonal to a drywall axis  54  defined by the first outer layer  42 . In this manner, the blade-saw assembly  50  is held substantially orthogonal to the plane of the drywall  40  when cutting the drywall  40 . 
         [0035]    Referring now to  FIG. 4 , the saw  12  is pressed toward the drywall  40  to cause the saw guard  55  to be disposed adjacent the first outer layer  42 . Furthermore, the blade  10  is advanced through the drywall  40  to cause the blade tip  28  to pass through the first outer layer  42  and the drywall inner layer  46 . The blade tip  28  also comes in contact with the second outer layer  44 . In one embodiment, the blade tip  28  may be configured to completely pass through the second outer layer  44 . This may be desirable to make a cleaner and more efficient cut of the drywall  40 . However, in another embodiment, the blade tip  28  may not pass completely through the second outer layer  44 . It may be desirable to mitigate complete blade tip  28  penetration through the second outer layer  44  to protect against inadvertent contact with utilities. For instance, if a user knows, or has good reason to believe that utilities are disposed adjacent the second outer layer  44 , then full penetration of the second outer layer  44  by the blade tip  28  may be undesirable. 
         [0036]    Once the blade  10  reaches its fully advanced position, it retracts through the drywall  40 . Upon retraction, the teeth  34  may cut through the first outer layer  42  to facilitate removal of the blade  10  from the drywall  40 . The cutting of the first outer layer  42  by the teeth  34  mitigates bunching of the first outer layer  42 . In other words, if the first outer layer  42  is not cut by the teeth  34 , the first outer layer  42  has a tendency to gather and disrupt cutting of the drywall  40 . The smooth and planar body upper and lower edges  18 ,  16  enable the blade  10  to glide through the drywall inner layer  46 , which mitigates the amount of dust generated by cutting the drywall  40 . 
         [0037]    It is contemplated that one particular embodiment of the blade  10  does not include blade teeth  34 . Alternatively, the blade  10  may include blade teeth  34  that are not advanced into the drywall  34 . In this manner, the blade  10  does not have to be inserted to a point where the teeth  34  at least pass through the first outer layer  42 . Rather, the blade  10  may be inserted until the blade tip  28  contacts the second outer layer  44 . Once the blade tip  28  achieves penetration through the second outer layer  44 , further insertion is not required. This may be desirable when it is known that utilities are disposed in close proximity to the second outer layer  44 . By minimizing the penetration depth, the chance of puncture or other damage to the utilities is reduced. Another benefit to the blade  10  not having teeth  34  is that the blade  10  may cut the drywall  40  in two directions. More specifically, the blade  10  may cut the drywall  40  along the body upper edge  18 , or alternatively along the body lower edge  16 . 
         [0038]    When making the cut through the drywall  40 , the user presses the saw  12  against the drywall  40  to keep the saw guard  55  adjacent the first outer layer  42 . The user may also direct the saw  12  to in a direction to perform the desired cut. In this manner, the blade  10  reciprocates through the drywall  40  to make the cut. Once the user completes the desired cut, the blade  10  is removed from the drywall  40 , as illustrated in  FIG. 5 . 
         [0039]    The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combinations described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.

Technology Classification (CPC): 8