Abstract:
A pair of pliers including a first handle, a bolt movably mounted on the first handle, a first jaw secured to the first handle, a second jaw linked to the first handle, a spring connected between the first handle and the second jaw, a second handle linked to the second jaw, a strut linked to the second handle at an end and abutting the bolt at another end, and a lever linked to the second handle for control over the strut. The first jaw includes a tooth formed thereon and a flat edge formed next to the tooth. The second jaw includes a tooth and a concave edge formed next to the tooth thereof.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of Invention  
           [0002]    The present invention is related to a pair of pliers and more particularly to a pair of pliers that can retain a jaw thereof in position relative to another jaw thereof.  
           [0003]    2. Related Prior Art  
           [0004]    [0004]FIG. 9 shows a conventional pair of pliers that includes a body  10  with a first jaw  11  and a first handle (not numbered) extending from the jaw  11 . A second jaw  12  is I  11  linked to the body  10  by means of a pin  13 . A spring  17  includes an end secured to the second jaw  12  and an opposite end secured to the first handle. A second handle  14  is linked to the second jaw  12 . A strut  15  is linked to the second handle  14 . A bolt  16  is engaged with the first handle. A tip  151  of the strut  15  abuts a tip  161  of the bolt  16 . A lever  18  is linked to the second handle  14 . The lever  18  includes a first section  181  and a second section  182 . The strut  15  includes an elbow  152  in contact with the second section  182  of the lever  18 .  
           [0005]    This conventional pair of pliers can be used to drive a pipe with a smooth periphery or a bolt with a hexangular head. In use, the pipe or hexangular head is put between the jaws  11  and  12 . The bolt  16  is rotated in order to adjust the position of the second jaw  12  relative to the first jaw  11  based on the size of the pipe or hexangular head. The second handle  14  is pressed toward the first handle so that the jaws  11  and  12  close in and bites the pipe or hexangular head. The elbow  152  moves the second section  182  of the lever  18  toward the second handle  14 , thus moving the first section  181  of the lever  18  away from the second handle  14 . The pair of pliers is retained in this position by means of the spring  17 . Thus, a user does not have to grip the handles hard while rotating the pipe or bolt.  
           [0006]    When using the pair of pliers in a limited space, the user has to release the jaws from the pipe or hexangular head by moving the first section  181  of the lever  18  toward the second handle  14  after rotating the pipe or bolt by an angle. The afore-mentioned process has to be repeated in order to rotate the pipe or bolt by another angle. This is inconvenient.  
           [0007]    The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.  
         SUMMARY OF INVENTION  
         [0008]    It is an objective of the present invention to provide a pair of pliers that can retain a jaw thereof in position relative to another jaw thereof and is particularly convenient in driving a hexangular head of a bolt.  
           [0009]    According to the present invention, a pair of pliers including a first handle, a bolt movably mounted on the first handle, a first jaw secured to the first handle, a second jaw linked to the first handle, a spring connected between the first handle and the second jaw, a second handle linked to the second jaw, a strut linked to the second handle at an end and abutting the bolt at another end, and a lever linked to the second handle for control over the strut. The first jaw includes a tooth formed thereon and a flat edge formed next to the tooth. The second jaw includes a tooth and a concave edge formed next to the tooth thereof.  
           [0010]    The first handle includes a first section to which the first jaw is secured and a second section on which the bolt is movably mounted.  
           [0011]    The second section of the first handle defines a window through which a tip of the bolt can be seen. Two scales are marked on the second section of the first handle beside the window. The scales are calibrated so that a reading of the tip of the bolt in the scales indicates a distance between the tips of the jaws and or the size of an article to be driven by means of the pair of pliers.  
           [0012]    The first handle includes a hook projecting from the second section thereof for hooking an end of the spring.  
           [0013]    The first jaw may be secured to the first section of the handle by means of pin or soldering. Alternatively, the first handle and the first jaw may be made two portions of a single element.  
           [0014]    The pair of pliers includes a pin for linking the second jaw to the first handle.  
           [0015]    The pair of pliers includes a pin for linking the second handle to the second jaw.  
           [0016]    The pair of pliers includes a pin for linking the strut to the second handle.  
           [0017]    The strut includes an elbow formed thereon for contact with the lever.  
           [0018]    The pair of pliers includes a pin for linking the lever to the second handle, thus dividing the lever into a first section to be pressed and a second section for contact with the elbow of the strut.  
           [0019]    The first jaw may include a series of miniature teeth formed next to the flat edge, and the second jaw may include a series of miniature teeth formed next to the tooth.  
           [0020]    Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the attached drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0021]    The present invention is described through detailed illustration of embodiments referring to the attached drawings wherein:  
         [0022]    [0022]FIG. 1 is a perspective view of a pair of pliers in accordance with an embodiment of the present invention;  
         [0023]    [0023]FIG. 2 is a cross-sectional view of the pair of pliers shown in FIG. 1  
         [0024]    [0024]FIG. 3 is similar to FIG. 2 except for showing the pair of pliers engaged with a head of a bolt;  
         [0025]    [0025]FIG. 4 is similar to FIG. 3 except for showing the head rotated clockwise by 90 degrees from the position shown in FIG. 3 by means of the pair of pliers;  
         [0026]    [0026]FIG. 5 is similar to FIG. 4 except for showing counterclockwise rotation of the pair of pliers by an angle from the position shown in FIG. 4 without rotation of the head;  
         [0027]    [0027]FIG. 6 is a side view of a pair of pliers according to another embodiment of the preferred embodiment of the present invention;  
         [0028]    [0028]FIG. 7 is a side view of a pair of pliers according to a third embodiment of the present invention engaged with a head of a bolt;  
         [0029]    [0029]FIG. 8 is similar to FIG. 7 except for showing the pair of pliers engaged with a pipe; and  
         [0030]    [0030]FIG. 9 is a side view of a conventional pair of pliers. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0031]    Referring to FIGS. 1 and 2, a pair of pliers according to an embodiment of the present invention includes a first handle  20 , a first jaw  30 , a second jaw  40 , a second handle  50 , a strut  60 , a spring  70  and a lever  80 .  
         [0032]    The first handle  20  includes a first section  21  and a second section  22 . The second section  22  of the first handle  20  is engaged with a bolt  23 . A hook  24  projects from the second section  22 . The second section  22  of the first handle  20  defines a window through which a tip of the bolt  23  can be seen. Two scales  251  are marked on the second section  22  of the first handle  20  beside the window  25 . The scales  251  are calibrated so that a reading of the tip of the bolt  23  in the scales  251  indicates a distance between the tips of the jaws  30  and  40  or the size of an article to be driven by means of the pair of pliers.  
         [0033]    The first jaw  30  is connected with the first section  21  of the handle  20  by means of a pin  31 . The connection of the first handle  20  with the first jaw  30  may be enhanced by means of soldering. Thus, the first handle  20  and the first jaw  30  are integrated with each other. The first jaw  30  includes a tooth  32  projecting from a flat edge  33 . In this embodiment, the first handle  20  and the first jaw  30  are made two elements so that the first jaw  30  can be fabricated positively and, more particularly, the tooth  32  and the flat edge  33  can be shaped positively. However, the first handle  20  and the first jaw  30  can be made two portions of a single element.  
         [0034]    The second jaw  40  is linked to the first handle  20  by means of a pin  41 . The second jaw  40  can be pivoted relative to the first handle  20 . The spring  70  includes an end secured to the second jaw  40  and another end  72  secured to the first handle  30 . The first end  71  of the spring  70  is inserted through a hole defined in the second jaw  12 , and the second end  72  of the spring  70  is hooked to the hook  24  projecting from the first handle  20 . The second jaw  40  includes a tooth  42  and a concave edge  43  formed next to the tooth  42 .  
         [0035]    The second handle  50  is linked to the second jaw  40  by means of a pin  51 . The second handle  50  can be pivoted relative to the second jaw  40 .  
         [0036]    The strut  60  includes a first end, a second end  62  and an elbow  63  formed between the first and second ends thereof. The first end of the strut  60  is linked to the second handle  50  by means of a pin  61 . Thus, the strut  60  can be pivoted relative to the second handle  50 . The second end  62  of the strut  60  abuts a tip of the bolt  23 .  
         [0037]    The lever  80  is linked to the second handle  50  by means of a pin  81 , thus dividing the lever  80  into a first section and a second section. The elbow  63  of the strut  60  can be in contact with the second section of the lever  80 .  
         [0038]    The pair of pliers according to the present invention is very similar to the conventional pair of pliers described in the Related Prior Art except for including the novel jaws  30  and  40 . Therefore, the following description of the pair of pliers according to the present invention will be focused on the jaws  30  and  40 .  
         [0039]    [0039]FIG. 3 shows a hexangular head  90  of a bolt (not shown) engaged with the pair of pliers. The hexangular head  90  includes corners  1 ˜ 6 . To rotate the bolt clockwise, the hexangular head  90  is located between the jaws  30  and  40 . The bolt  23  is rotated in order to properly position the second jaw  40  relative to the first jaw  30  based on the size of the hexangular head  90 . The second handle  50  is pressed toward the first handle  20  so that the jaws  30  and  40  close in until the tooth  32  abuts the corner  1  from the left and the tooth  42  abuts the corner  4  from the right. The elbow  63  pushes the second section of the lever  80  toward the second handle  50 , thus moving the first section of the lever  80  away from the second handle  50 . The pair of pliers is retained in this position by means of the spring  70  so that a user does not have to grip the handles  20  and  50  hard while rotating the bolt. For the tooth  32  abuts the corner from the left and the tooth  42  abuts the corner  4  from the right, clockwise pivot of the pair of pliers results in clockwise pivot of the bolt.  
         [0040]    When using the pair of pliers in a limited space, the user may only be allowed to pivot it from the position shown in FIG. 3 to the position shown in FIG. 4 before he or she has to pivot it counterclockwise as shown in FIG. 5. The concave edge  43  of the second jaw  40  allows the jaws  30  and  40  to rotate counterclockwise relative to the hexangular head  90 . Thus, the user can pivot the pair of pliers counterclockwise by an angle. When appropriate, the user can pivot the pair of pliers clockwise without rotating the bolt until the tooth  32  abuts a corner of the hexangular head  90  such as the corner  6  from the left and the tooth  42  abuts another corner of the hexangular head  90  such as the corner  4  from the right. Further clockwise pivot of the pair of pliers results in clockwise pivot of the bolt.  
         [0041]    [0041]FIG. 6 shows a pair of pliers in accordance with a second embodiment of the present invention. The pair of pliers shown in FIG. 6 is identical to the pair of pliers shown in FIGS.  1 ˜ 5  except for including jaws  30 ′ and  40 ′ that are longer and sharper than the jaws  30  and  40 .  
         [0042]    [0042]FIG. 7 shows a pair of pliers according to a third embodiment of the present invention. The pair of pliers shown in FIG. 7 is identical to that shown in FIGS.  1 ˜ 5  except for including jaws  30 ″ and  40 ″ instead of the jaws  30  and  40 . The first jaw  30 ″ is identical to the first jaw  30  except for including a series of the teeth  34  formed to the right of the flat edge  33 . The second jaw  40 ″ is identical to the second jaw  40  except for two features. Firstly, instead of the concave edge  43 , an inclined edge  43 ″ is formed on the second jaw  40 ″. The inclined edge  43 ″ extends from the tooth  42  to the tip of the second jaw  40 ″. Finally, the second jaw  40 ″ includes a series of the teeth  44  formed to the right of the tooth  42 .  
         [0043]    As shown in FIG. 7, the tooth  32  of the first jaw  30 ″ and the tooth  42  of the second jaw  40 ″ can be engaged with the hexangular head  90 . As shown in FIG. 8, the series of teeth  34  of the first jaw  30 ″ and the series of teeth  44  of the second jaw  40 ″ can be engaged with a pipe  92 .  
         [0044]    The present invention has been described through detailed illustration of the preferred embodiment thereof. Those skilled in the art can derive many variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention. The scope of the present invention can only be defined in the attached claims.