Patent Publication Number: US-2005115086-A1

Title: Hacksaw with support arm

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to hacksaws. In particular, the present invention relates to a hacksaw having a retractable support arm to protect the user&#39;s wrist.  
      2. Description of the Related Art  
      Hand tools often require that downward pressure be placed on the tool using the muscles of the wrist and hand while at the same time maintaining the orientation of the extended tool by applying a moment about an axis perpendicular to the handle and the user&#39;s forearm. This places an inordinate amount of stress on the user&#39;s wrist and can be painful if such stress is prolonged.  
      There have been many attempts at relieving the stress associated with such tools, but they are generally bulky and impractical.  
      For example, U.S. Pat. No. 4,941,261, issued Jul. 17, 1990 to Glenn, discloses a knife with an integrally-formed support arm. The support arm extends to the forearm of the person holding the knife and thereby maintains the orientation of the knife with respect to the arm during use. Since it is less stressful to simply push down on the handle than to push down on the handle while at the same time keeping the knife pointed out from the arm, the support arm significantly reduces the stress associated with using the knife. However, the support arm is not adjustable for various users, nor is it retractable.  
      U.S. Design Pat. D463,083, issued Sep. 17, 2002 to Kari et al., discloses an ice scraper having a support arm. Again, the wrist brace is neither adjustable nor retractable.  
      U.S. Pat. No. 5,379,758, issued Jan. 10, 1995 to Snyder discloses a surgical retractor having an extended support arm. A fulcrum is created at the attachment between the hand grip and the handle so that stronger muscles of the user are available with a mechanical advantage instead of relying on the wrist muscles.  
      U.S. Pat. No. 5,471,700, issued Dec. 5, 1995 to Pereira, discloses a grill scraping tool having a forearm embracing portion at the proximal end. The tool purportedly protects the user against burning and requiring only one hand to generate sufficient leverage against the grill surface.  
      Finally, U.K. Patent Application GB 2,248,034, published Mar. 25, 1992 by Anderson, discloses a shovel handle adapted for use with one arm by providing a forearm support structure.  
      Accordingly, the prior art as a whole teaches the concept of providing a hand tool with a support arm extending to a user&#39;s forearm to leverage the stronger muscles in the arm thereby reducing strain on the wrist. However, they fail to show a hand tool having a support arm that is easily retractable or repositionable to suit a variety of different users.  
      Thus, none of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. A hacksaw with support arm solving the aforementioned problems is desired.  
     SUMMARY OF THE INVENTION  
      The hacksaw with support arm includes a frame having an elongated top portion extending along an axis generally from the front to the back of the frame, a front leg extending from said the axis and a back leg extending from the axis, the legs having means for supporting a blade from distal ends thereof. A support arm slidingly engages the elongated top portion. The support arm is extensible rearwardly of the back leg in the direction of the axis. The support arm includes an arm support for resting against a user&#39;s forearm during use.  
      Accordingly, it is a principal object of the invention to provide a hacksaw that requires less strain and effort than previous hacksaws.  
      It is another object of the invention to provide a support arm for a hacksaw that adjusts to improve the comfort and reduce wrist strain for a variety of users.  
      It is a further object of the invention to provide a hacksaw with an extensible support arm that can be retracted or extended depending on the preference of the user.  
      It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.  
      These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an environmental, perspective view of a hacksaw with support arm according to an embodiment of the present invention.  
       FIG. 2  is a perspective view of the hacksaw of  FIG. 1  showing salient features thereof.  
       FIG. 3  is partial cut-away view of the hacksaw of  FIGS. 1 and 2  showing the latch adjustment mechanism.  
    
    
      Similar reference characters denote corresponding features consistently throughout the attached drawings.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       FIG. 1  shows a hacksaw  10  having an extensible arm  20  to relieve wrist strain. As will be described in detail below, extensible arm  20  is adjustable and fully retractable so that hacksaw  10  may be used as an ordinary hacksaw or as one with added the advantages of an adjustable support arm.  
      Referring now to  FIG. 2 , hacksaw  10  includes a frame  15  supporting blade  17  in any known manner. Frame  15  includes an elongated top portion  23  extending generally along an axis, a front leg  24  extending away from the axis of top portion  23 , and a back leg  26  also extending away from the axis of top portion  23 . Front leg  24  and back leg  26  may extend generally perpendicularly from top  23  to form C-shaped frame  15 . Blade  17  is retained by and extends between distal ends of front leg  24  and back leg  26  of frame  15  as is generally known and understood in the art.  
      Hacksaw  10  also includes a handle  22 . Handle  22  is fixed to and extends from top portion  23  behind back leg  26  thereby providing a space for a user&#39;s fingers to wrap around handle  22 , as shown in  FIG. 1 . Handle  22  is connected to frame  15  at the top of handle  22  and to the distal end of back leg  26 . However, it is also contemplated that handle may be attached only at its top to frame  15 , as is known in the art and sometimes referred to as a “pistol grip.” It is also contemplated that back leg  26  may double as a handle such that a separate handle  22  is not needed. Frame  15  and handle  22  are preferably made of metal or composite material and may manufactured by any generally known method. Handle  22  may also be made of plastic or other suitable moldable material. For example, frame  15  may be made of cast aluminum or aluminum alloy and handle  22  made of impact-resistant plastic.  
      Referring now to  FIG. 3 , top  23  slidingly receives extensible arm  20  which has a U-shaped cross-section with the legs of the “U” pointing down towards the blade. Note that, while extensible arm  20  preferably has a U-shaped cross-section, other cross-sections are possible. For example, extensible arm  20  may be formed from a simple strip of metal or other stiff material lying generally in the plane of blade  17 . However, to increase lateral strength, it is preferred that arm  20  have significant lateral dimension. For example, extensible arm  20  may have an angle-shaped cross section, T-shaped cross, section, I-shaped cross section, etc. Extensible arm  20  may also be formed from a solid rod, bar, or hollow tube. Thus, the actual shape of extensible arm  20  may depart from the preferred shape without departing from the spirit and scope of the invention.  
      A trigger-actuated latch mechanism  25  is conveniently provided just forward of back leg  26 . Referring now to  FIG. 4 , latch mechanism  25  includes a latch  27  including a trigger portion  31 , a latching portion  39  a pivot  29  and a spring  33 . Latch  27  is preferably formed of moldable material such as plastic or metal.  
      Spring  33  is shown as a coiled compression spring, however springs of other shapes are contemplated. For example, spring  33  may be formed of plastic and molded integrally with latch  27 . Spring  33  therefore urges latch  27  to rotate in a clockwise direction about pivot  29  as shown in  FIG. 4  by biasing against wall  26  formed in frame  15 . Pivot  29  may comprise a pin extending through frame  15  and latch  27 .  
      Latching portion  39  is therefore biased by said spring to engage notches  37  formed in a lower edge of extensible arm  20 . To release latching portion  39  from one of notches  37 , the user simply pulls on trigger  31 , overcoming the force generated by spring  33  to rotate latch  27  counter-clockwise about pivot  27  thereby disengaging latching portion  39  from notch  37 . The user is then free to retract, extend, or reposition extensible arm  201 . Once extensible arm  20  is in the desired position, trigger  31  is released and latching portion  39  will engage a notch  37  upon alignment of latching portion  39  with one of notches  37 .  
      Hacksaw  10  may therefore be used with extensible arm  20  in the fully retracted state where it looks and operates just like an ordinary hacksaw. However, when extended or rigorous use is anticipated, the user may depress trigger  31  and extend retractable arm  20  it to any of a plurality of degrees of extension thereby providing a support arm having a comfortable length to suit any user. By allowing arm support  14  to rest against the user&#39;s forearm, hacksaw  10  may be used with significantly less strain on the user&#39;s wrist.  
      It is to be understood that the present invention is not limited to the embodiment described above, but encompasses any and all embodiments within the scope of the following claims.