Abstract:
An improved wrench includes a housing with opposite first and second ends and a pair of gears rotatably mounted in the first and second ends respectively. Each gear has a cylindrical sidewall with opposite ends and a plurality of teeth forming a sprocket extending radially outwardly from the sidewall between the opposite ends. A chain is trained about the gears within the housing. Upper and lower bushings are mounted in each end of the housing adjacent the sidewall of the respective gears to prevent contact between the gear sidewall and the housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 of a provisional application Ser. No. 61/222,549 filed Jul. 2, 2009, and, which application is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed towards a wrench having a slim profile for tightening and loosening nuts and fasteners in tight spaces or otherwise having limited access. 
       BACKGROUND OF THE INVENTION 
       [0003]    Wrenches of various sizes and shapes are commonly used for tightening and loosening nuts and bolts. One common type of wrench is a socket wrench including a socket rotated in clockwise and counterclockwise directions by a drive lever or arm. The socket typically includes a square hole on one end to matingly receive the square male drive shaft of the wrench, and a hexagon or multifaceted opening on the other end for receipt of the nut or bolt head. 
         [0004]    Specialty flat or slim profile wrenches are also known for reaching nuts and bolts in tight spaces. Both gear drive and chain drive flat wrenches are known from the prior art. The gear drive wrenches include a plurality of intermeshing gears, which increases the manufacturing cost due to the number of pieces in the wrench. Chain drive flat wrenches generally are light weight and do not allow substantial torque to be applied to the nut or bolt head. These conventional wrenches often include a ratcheting mechanism to speed the process. However, with or without the ratchet action, the wrench must rotate about the nut to turn the nut. Thus, the wrench handle requires space to allow movement along a turning arc. 
         [0005]    Therefore, a primary objective of the present invention is the provision of an improved slim profile wrench for reaching nuts and bolts in tight spaces. 
         [0006]    Another objective of the present invention is the provision of a flat wrench having snap-in wear bushings on the sprockets at each end of the wrench. 
         [0007]    A further objective of the present invention is the provision of a wrench with a first rotatable end which can be driven remotely from the opposite end. 
         [0008]    Yet another objective is the provision of a wrench which can be used to tighten and loosen various types of rotational fasteners, including nuts and bolts, and screws having various heads. 
         [0009]    A further objective of the present invention is the provision of an improved wrench which can remain in one position during use, without the need for a turning arc space for the wrench handle. 
         [0010]    Another objective of the present invention is the provision of a flat wrench having a heavy duty chain drive. 
         [0011]    Another objective of the present invention is the provision of a tight reach wrench having one piece with opposite female ends. 
         [0012]    Yet another objective of the present invention is the provision of a wrench having gears at each end with bushings engaging the sidewalls of the gears to preclude contact between the gear and the wrench housing. 
         [0013]    Still another objective of the present invention is the provision of a wrench having gears which are flush with the exterior wrench housing. 
         [0014]    Another objective of the present invention is the provision of a slim profile wrench which can be coupled with other similar wrenches in an end-to-end series through male to male couplers. 
         [0015]    Another objective of the present invention is the provision of a flat wrench having an internal channel or track for guiding the drive chain. 
         [0016]    Still another objective of the present invention is the provision of a flat wrench having flush sockets and drives. 
         [0017]    Another objective of the present invention is the provision of a flat, slim profile wrench for use in tight spaces which is economical to manufacture, and durable in use. 
         [0018]    These and other objectives will become apparent from the following description of the invention. 
       SUMMARY OF THE INVENTION 
       [0019]    A slim profile wrench is provided for reaching nuts and bolts in tight spaces. The wrench includes first and second rigid casing members secured together to form a housing and having opposite ends. An internal wall in at least one casing member defines longitudinally extending channels or tracks for a drive chain. The casing members are secured together by fasteners extending into the central channel wall. Rotatable sprocket gears are provided at each end of the wrench. Each sprocket has a female drive on each end or side of the wrench. Each end of each casing member includes a recess for snap-fit receival of a wear bushing residing on each end of each sprocket. The sprocket drives are flush with the exterior surface of the casing members so that the wrench has flat upper and lower surfaces. The drive chain extends around the sprockets and along the internal channel in the housing to transfer rotational drive from the gear at one end of the wrench to the gear at the other end. Thus, the wrench handle does not need to pivot about a nut during use, and no ratcheting mechanism is required. Multiple wrenches can be connected in an end-to-end series through the use of an adapter or coupler having opposite male ends. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a perspective view of the wrench of the present invention. 
           [0021]      FIG. 2  is an exploded perspective view of the wrench of the present invention. 
           [0022]      FIG. 3  is a partially exploded perspective view of the wrench in a partially assembled state. 
           [0023]      FIG. 4  is a perspective view of one of the bushings of the wrench. 
           [0024]      FIG. 5  is a plan view of the bushing. 
           [0025]      FIG. 6  is a side elevation view of the bushing. 
           [0026]      FIG. 4A  is a perspective view of an alternative embodiment of the bushing. 
           [0027]      FIG. 5A  is a plan view of the alternative bushing. 
           [0028]      FIG. 6A  is a side elevation view of the alternative bushing. 
           [0029]      FIG. 7  is a perspective view of one embodiment of the sprocket gear of the wrench. 
           [0030]      FIG. 8  is a side elevation view of the gear. 
           [0031]      FIG. 9  is a plan view of the gear. 
           [0032]      FIG. 10  is a perspective view showing the wrench used with a drive ratchet wrench. 
           [0033]      FIG. 11  is a side elevation view of the male-to-male connector which mounts the drive wrench to the slim profile wrench of the present invention. 
           [0034]      FIG. 12  is a side elevation view of an alternative extension having a Phillips tip for turning a Phillips head screw or fastener. 
           [0035]      FIG. 13  is a side elevation view of another alternative extension with a flat blade tip for turning a screw having a slotted head. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    The wrench  10  has a slim profile for use in tightening and loosening nut and/or bolts in tight spaces having minimal clearance. The upper and lower outer surfaces of the wrench are flat, for ease of insertion into a small space without interference. 
         [0037]    The wrench includes first and second casing members  12 ,  14 , which in a preferred embodiment, are identical to one another. The casing members are preferably cast metal. Each casing member  12 ,  14  includes a perimeter lip  34 . The casing members  12 ,  14  include holes for receiving threaded fasteners  13 . The holes on one of the casing members  12 ,  14  are threaded, while the holes on the other of the casing members  12 ,  14  are not threaded, such that the fasteners  13  extend through the unthreaded holes for threaded receipt in the threaded holes. When the casing members  12 ,  14  are assembled, the perimeter lips  34  engage one another so as to form a housing and enclose a chain  18 . 
         [0038]    Each casing member  12 ,  14  has an internal wall  20  extending longitudinally, so as to define channels or tracks on opposite sides of the wall  20 . The channels provide a track for the chain  18 , while the wall  20  precludes the chain  18  from rubbing against itself between the ends of the wrench. In an alternative embodiment, the wall can be formed on one casing member, while the other casing member has a flat inside surface to abut the wall when the members are assembled. 
         [0039]    The wrench also includes gear sprockets  16  at the opposite ends, with the internal chain  18  trained about the sprockets to rotate the sprockets in clockwise and counterclockwise directions, as described below. Each sprocket  16  includes female drives  17  on each end. Preferably, the sprocket  16  is formed as a one piece unit for strength and ease of assembly of the wrench. Each sprocket  16  includes a cylindrical body  19  with opposite ends  21 , and a sidewall  23  with a plurality of teeth  25  extending radially outwardly approximately mid-way between the opposite ends. 
         [0040]    Each casing member  12 ,  14  includes a circular opening  29  through which the ends of the sprocket  16  extends. A wear bushing  30  is snap-fit into each casing opening  29  so as to preclude direct contact between the sprocket sidewall  23  and the casing member  12 ,  14 . Preferably, the bushings  30  are snap-fit, press-fit, or friction-fit into the casing opening  29 , so as to be fixed with respect to the opening  29 , and without rotation in the opening  29 . Such a snap-fit is achieved through mating surfaces on the bushing  30  and the casing member  29 . As seen in  FIGS. 6-8 , the bushing  30  has opposite sides  31 , with a central diameter  33  slightly greater than the diameter at each side  31  of the bushing  30 . Thus, the bushing  30  includes a central perimeter portion with a slightly curved profile, which in a preferred embodiment, is matingly received in the casing member opening  29 , which has a corresponding curved wall or recess. If the bushing  30  becomes worn, it can be easily pushed out of the casing member  12 ,  14  and replaced with a new bushing. The bushings provide a bearing surface at each drive end  21  of the sprocket  16 , between the sprocket sidewall  23  and the edge of the hole  29 , to rotatably support the sprocket  16  in the casing member  12 ,  14 . Preferably, the bushing  30  is made of an ultra high molecular weight material. 
         [0041]    In an alternative embodiment, a bushing  30 A shown in  FIGS. 6A-8A . The bushing  30 A includes one or more tabs  35  to be received in a notch formed in the annular wall of the opening  29  of the casing member  12 ,  14 , so as to assure that the bushing  30 A will not rotate within the casing. 
         [0042]    In use, one of the female drives  17  receives a coupler  22  with opposite male ends  24  and a socket  26  to be placed on the nut, and the second or outer female drive receives a drive shaft from another wrench  28  or drill so as to turn the socket  26  via the drive chain  18 . The female drives  17  of each sprocket  16  preferably are in the form of a square hole to matingly receive a square drive shaft on the conventional socket wrench  28 , as seen in  FIG. 10 . Thus, when the socket wrench  28  is actuated to rotate the female drive  17  at one end of the wrench, the socket  26  at the other end of the wrench is rotatably driven by the chain  18  so as to tighten or loosen the nut and bolt assembly. Thus, either end of the wrench  10  can be used as the drive end and the socket end. 
         [0043]    As another option, an extension or adapter  36  with a square male end  38  can be inserted into one of the female drives, with the extension having a head adapted to tighten and loosen various fasteners, such as screws having a Phillips head  40 , a straight slot head  42 , a hex head, or a torx head.  FIG. 12  shows an extension having a Phillips head  40 , while  FIG. 13  shows an extension having a head  42  for a slotted screw. As another alternative, the extension  36  may be magnetized so that the fastener is magnetically connected to the extension  36  when removed. Similarly, the sprockets  16  can be magnetized, with the magnetism automatically passing through the inserted socket  26  or extension  36  to retain a fastener after loosening and removal. 
         [0044]    As an alternative, the female socket  17  of each sprocket  16  preferably has a hexagon opening or a multi faceted opening adapted to fit over the head of a bolt or onto a nut. A set of wrenches can be provided each having different sized female sockets, in English and/or metric versions. Thus, each wrench is an integral unit, and the set of wrenches eliminates the need to substitute different sized sockets in a single wrench. 
         [0045]    Multiple wrenches  10  can also be used in an end-to-end series for an extended reach. For such an end-to-end series, then adapter  22  is provided which has a square male head  42  on each end for receipt in the female drive  17  of the respective wrenches. The adapter may lock the wrenches in a desired angular relationship. Adapters with different lengths may be provided. 
         [0046]    The chain tracks and the integral, one piece construction of each sprocket  16 , allows the wrench  10  to apply high torque. Also, pneumatic drives can be applied to the wrench  10 . 
         [0047]    The wrench  10  functions with a 0° turning arc. In other words, the wrench  10  does not require any lateral space to pivot, as in conventional wrenches. The housing of the wrench  10  remains stationary relative to the nut, and only the female drives  17  and chain  18  rotate. 
         [0048]    The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.