Abstract:
A strap wrench comprising a gripping member, a flexible member, an end of the gripping member comprising a first slot for receiving the flexible member, a locking member engagable within a flexible member wrap portion, the flexible member wrap portion and locking member having an interference engagement within the first slot, a second slot parallel to the first slot for receiving another end of the flexible member, and the locking member having a tapered cross-sectional form and having a surface texture for frictionally engaging the flexible member wrap portion within the first slot.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a strap wrench, and further to a strap wrench comprising a locking member having a cross-sectional form and having a surface texture for frictionally engaging a flexible member wrap portion within a first slot. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many different strap wrenches have been developed over the years. Most include a strap attached to a handle, with a loose end that is coupled to the handle once the loop of the strap is made to be a desired size. The handle provides leverage to tighten the strap while turning the object enclosed by the strap. 
         [0003]    Some strap wrenches have a tendency for the strap to slip on the work as the handle is turned. In others the loose end of the strap will loosen while the handle is turned. 
         [0004]    Various uses include as oil filter wrenches or for removal of chain sprockets. Strap wrenches may be used on any workpiece that is not amenable to a box end or open end wrench, such as large diameter workpieces. 
         [0005]    Representative of the art is U.S. Pat. No. 8,555,753 which discloses a strap wrench including a strap that is a continuous loop and has notches. No portion of the strap is affixed to any portion of the wrench. The strap is placed around an object that needs to be turned such as an oil filter on an engine. A tension mechanism is then used to tighten the strap into place around the object to be turned. A ratchet mechanism engages one or more notches on the strap to prevent movement of the strap in one direction while allowing movement of the strap in the opposite direction. The combination of the notched continuous loop strap and ratchet mechanism allow the strap wrench to have a ratcheting action after the strap is tightened into place around the object to be turned. 
         [0006]    What is needed is a strap wrench comprising a locking member having a cross-sectional form and having a surface texture for frictionally engaging a flexible member wrap portion within a first slot. The present invention meets this need. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary aspect of the invention is to provide a strap wrench comprising a locking member having a cross-sectional form and having a surface texture for frictionally engaging a flexible member wrap portion within a first slot. 
         [0008]    Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings. 
         [0009]    The invention comprises a strap wrench comprising a gripping member, a flexible member, an end of the gripping member comprising a first slot for receiving the flexible member, a locking member engagable within a flexible member wrap portion, the flexible member wrap portion and locking member having an interference engagement within the first slot, a second slot parallel to the first slot for receiving another end of the flexible member, and the locking member having a tapered cross-sectional form and having a surface texture for frictionally engaging the flexible member wrap portion within the first slot. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with a description, serve to explain the principles of the invention. 
           [0011]      FIG. 1  is a bottom perspective view of the strap wrench. 
           [0012]      FIG. 2  is a top perspective view of the strap wrench. 
           [0013]      FIG. 3  is a cross-sectional view of the strap wrench. 
           [0014]      FIG. 4  is a perspective view of the locking member. 
           [0015]      FIG. 5  is a cross-sectional view of the locking member. 
           [0016]      FIG. 6  is a top perspective view of the wrench head. 
           [0017]      FIG. 7  is a bottom perspective view of the wrench head. 
           [0018]      FIG. 8  is a perspective view of an alternate locking member. 
           [0019]      FIG. 9  is an end view of the alternate locking member in  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]      FIG. 1  is a bottom perspective view of the strap wrench. The inventive strap wrench comprises a gripping member  10  connected to an end or head portion  50 . A flexible member  150  is engaged with end  50 . 
         [0021]    Flexible member  150  comprises a strap of any suitable material known in the art, for example, elastomer, nylon, poly, metallic or natural material. Flexible member  150  may also comprise a multi-ribbed belt used for power transmission in the automotive or industrial industries. The multi-ribbed belt may comprise a plurality of tensile cords  153  embedded in the belt which enhance the tensile load bearing properties of the belt. The tensile cords run in a lengthwise direction. In the multi-ribbed embodiment the ribs run lengthwise in the longitudinal direction. Flexible member  150  is not a continuous loop, that is, it comprises a length having a proximal and distal end. Flexible member  150  may also be flat on both sides wherein a multi-ribbed surface is not present. 
         [0022]      FIG. 2  is a top perspective view of the strap wrench. Surface  11  is for a user to grip the tool. 
         [0023]      FIG. 3  is a cross-sectional view of the strap wrench. End  50  comprises a first slot  51  and a second slot  52 . First slot  51  and second slot  52  are parallel. Gripping member  10  comprises a gripping member centerline axis A-A. Second slot  52  is disposed between the first slot  51  and gripping member axis A-A with reference to a direction normal to axis A-A. First slot  51  is disposed radially outward of the second slot  52  with respect to the gripping member. 
         [0024]    Flexible member wrap portion  152  is wrapped about a locking member  151 . Wrap portion  152  and locking member  151  have an interference fit within first slot  51 , thereby preventing pull out of the flexible member during use. First slot  51  is wider at one end  51   b  to facilitate the interference fit, see  FIG. 7 . Wider end  51   b  of first slot is the end that receives the wrap portion and locking member combination. The end of flexible member  150  which is wrapped about locking member  151  extends within the first slot and is then folded back on itself so it reengages flexible member  150 , all within first slot  51 . 
         [0025]    When in use the flexible member  150  exerts a force “L” on wrap portion  152  and locking member  151 . Force “L” is represented by a vector L. An end of the flexible member is disposed for pressing engagement against the gripping member  10  by a user. A user grips the gripping member while simultaneously gripping a loose end of the flexible member  150  thereby pressing it against the gripping member surface  11  which is knurled. Knurling on surface  11  enhances the grip capacity on the flexible member, which increases the torque capacity of the strap wrench. A force F applied by a user causes flexible member  150  to tightly engage a work piece (not shown). 
         [0026]    The size capacity of the wrench may be adjusted by either extending or retracting the loose end of the flexible member through second slot  52 . The loose end of flexible member  150  is simply pulled snug against the work piece and then gripped against surface  11  by the user. 
         [0027]      FIG. 4  is a perspective view of the locking member. Locking member  151  comprises a tapered form when viewed in cross-section. Locking member  151  comprises a textured surface which engages the flexible member  150 . The textured surface may comprise a plurality of parallel elongate grooves  156  extending normal to the taper direction for gripping the flexible member  150  within the first slot  51 . The textured surface of locking member  151  may also comprise knurling, striations or any other surface feature suitable for a frictional engagement with the flexible member  150 . 
         [0028]      FIG. 5  is a cross-sectional view of the locking member. When engaged in first slot  51  the taper of locking member  151  from broad end to narrow end extends in the direction of vector L, see  FIG. 3 . Locking member  151  comprises a major curved portion  153  which faces a minor curved portion  154 . The radius of the major curved portion is greater than the radius of the minor curved portion. Planar portions  155  extend between portion  153  and portion  154 . This may also be referred to as a “tear drop” shape. 
         [0029]    Grooves  156  comprise a rectilinear cross-section, see  FIG. 5 . The rectilinear cross-section facilitates the frictional gripping action between locking member  151  and the flexible member  150 . Grooves  156  may also be triangular, arcuate or other suitable cross-section to create a frictional engagement with the flexible member  150 . 
         [0030]      FIG. 6  is a top perspective view of the wrench head. Wrench head  50  is disposed at an end of gripping member  10 . First slot  51  and second slot  52  are adjacent to each other and are parallel. Ribbed surface  53  is disposed adjacent second slot  52 . Ribbed surface  53  engages flexible member  150  to increase purchase when the wrench is in use. 
         [0031]      FIG. 7  is a bottom perspective view of the wrench head. 
         [0032]      FIG. 8  is a perspective view of an alternate locking member. In an alternate embodiment locking member  251  may comprise a triangular cross-section having three sides  255 . Sides  255  are joined by arcuate vertices  253  disposed therebetween. Locking member  251  is a triangular cross-section may comprise a smooth, textured, or grooved surface  256  for frictionally gripping the flexible member  150  within the first slot  51 . Locking member  251  may also comprise a circular cross-section having a smooth, textured or grooved surface for gripping the flexible member  150  within the first slot  51 . 
         [0033]    Grooves  256  comprise a rectilinear cross-section. The rectilinear cross-section facilitates the gripping action between locking member  251  and the flexible member  150 . Grooves  256  may also be triangular, arcuate or other suitable cross-section to create a frictional engagement with the flexible member  150 .  FIG. 9  is an end view of the alternate locking member in  FIG. 8 . 
         [0034]    Although a form of the invention has been described herein, it will be obvious to those skilled in the art that variations may be made in the construction and relation of parts without departing from the spirit and scope of the invention described herein.