Abstract:
The present invention provides novel ratchet head configurations for externally capturing a ratchet mechanism within the head of a powered ratchet wrench, such as a pneumatic ratchet wrench for example. Externally capturing the ratchet mechanism prevents the separation of the ears of the ratchet mechanism, caused by the application of torque to the ratchet head design. In prior art designs, repeated application of torque to the ratchet head caused separation of the ratchet head ears, and in turn, malfunctioning of the ratchet caused by loss of tension between the yoke of the ratchet and ratchet head itself. By preventing the ears from separating, the present invention maintains proper operation, and increased tool life. Furthermore, the tools maintenance and repair costs are decreased.

Description:
FIELD OF THE INVENTION 
     The present invention is generally a novel powered ratchet head design. More specifically, the present invention is a ratchet head design having external features for retaining the ratchet mechanism within the head. 
     BACKGROUND OF THE INVENTION 
     Various powered ratchet wrench designs have been designed, manufactured and marketed. As shown in FIG. 1, the prior art design is shown at  10  having a head portion  12  and a handle portion  14 . Within head portion  12  is a ratchet mechanism  16 , which is enclosed within a yoke  18 . Handle portion  14  includes a housing  20  which encloses a drive motor, not shown. Generally, such drive motors have been pneumatic, but other motors have been utilized. The end of handle portion  14  contains a compressed air inlet port  22 , which connects to a compressed air supply by various means known in the art. An actuation button or lever  24  is located between air inlet port  22  and housing  20 , which allows the operator to actuate the pneumatic motor, the drive mechanism (not shown) and ratchet mechanism  16 . 
     As shown in FIG. 2, the prior art ratchet mechanism  16  contains a shift lever  25 , a pawl  28  and a ratchet body  30  having a drive square  26 . Alternatively, ratchet mechanism  16  may contain more than one pawl  28 . Ratchet mechanism  16  fits within yoke  18  in order to allow for rotation of drive square  26  caused by interaction of pawl  28  and the teeth formed on yoke  18 . 
     When assembled, ratchet mechanism  16  is retained within ratchet head  12  on one end by ear  11  of ratchet housing  12 , which is in contact with the upper end of ratchet body  30 , opposite drive square  26 , and on the other end by an internal snap ring  32 , which fits within a groove  34  formed within ear  13 , of ratchet head  12 . Between snap ring  32  and the lower end of ratchet body  30  is provided a tensioning means, such as a compressed belleville spring washer  31 , for example. The belleville spring washer or belleville washer  31 , is held in a compressed state between the lower end of ratchet body  30  and snap ring  32 . Compressed belleville washer  31  biases ratchet body  30  toward ear  11  of head portion  12  and provides friction for ratchet mechanism  16 . This friction is commonly referred to in the art as head tension or simply tension, and allows for advancement of ratchet mechanism  16  within yoke  18 , as yoke  18  moves with reciprocating motion within ratchet head  12 . 
     Because the ratchet mechanism  16  is retained internally within ratchet housing  12  between ears  11  and  13 , when torque is applied to the ratchet head, the ears  11 ,  13  of ratchet head  12  begin to widen apart or spread. Upon repeated application of torque to ratchet head  12 , ears  11  and  13  may remain in a spread position. This causes ratchet mechanism  16  to function improperly and slip upon application of force to drive square  26  because ears  11  and  13  no longer hold the tensioning means in a compressed state, and the resulting loss of tension between the tensioning means, for example a belleville spring washer, and the ears  11  and  13  does not allow ratchet mechanism  16  to advance within yoke  18 . This is a significant problem in prior art ratchet head designs and increases the costs to maintain these ratchet wrenches for both the end user/owner and the ratchet wrench manufacturers. 
     Therefore, there is a need for an improved ratchet head design which prevents spreading of the ratchet head ears and thus, maintains proper operation of the ratchet mechanism of the pneumatic ratchet wrench. 
     SUMMARY OF THE INVENTION 
     It is a general object of the present invention to provide a powered ratchet wrench design which prevents spreading of the ratchet head, and thus proper operation of the ratchet wrench. 
     It is another object of the present invention to provide a powered ratchet wrench design which contains components which are easily replaceable upon excess wear. 
     It is yet another object of the present invention to provide a powered ratchet wrench that has decreased maintenance costs. 
     These and other objects of the present invention are accomplished by providing a ratchet head design which externally captures the ratchet mechanism between the ears of the ratchet head. Capturing the ratchet mechanism externally prevents the ears from spreading. The present invention also provides easily and rather inexpensively replaceable wear washers positioned adjacent the wear surfaces of the ratchet head. Through the prevention of spreading of the ratchet head and having replaceable wear surfaces, the life of the tool is increased. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a prior art ratchet head design; 
     FIG. 2 is an exploded perspective view of a prior art ratchet head design; 
     FIG. 3 is perspective view of a first preferred embodiment of the present invention; 
     FIG. 4 is an exploded perspective view of a first preferred embodiment of the present invention; 
     FIG. 5 is an exploded perspective view of a first preferred embodiment of the present invention. 
     FIG. 6 is a perspective view of an assembled first preferred embodiment of the present invention. 
     FIG. 7 is a front perspective view of an assembled second preferred embodiment of the present invention. 
     FIG. 8 is a rear perspective view of an assembled second preferred embodiment of the present invention. 
     FIG. 9 is an exploded perspective view of a second preferred embodiment of the present invention. 
     FIG. 10 is a front perspective view of an assembled third preferred embodiment of the present invention. 
     FIG. 11 is an exploded front perspective view of a third preferred embodiment of the present invention. 
     FIG. 12 is an exploded rear perspective view of a third preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     As shown in FIG. 3, there is shown a first preferred embodiment of the present invention, shown generally at  100  having a head portion  112  and a handle portion  114 . Head portion  112  has two ears  111  and  113  between which is inserted yoke  118 . Bores are formed within ears  111  and  113  to allow for placement of a ratchet mechanism  116  as described herein. Yoke  118  also has a bore formed therein having teeth formed about the circumference of the bore which engage teeth formed on a pawl  160  of ratchet mechanism  116 . Handle portion  114  includes a housing  120  which encloses a drive motor, not shown. Although a pneumatic drive motor is described as the preferred power source, and is well known in the art, other motors such as electric motors, can be used to drive ratchet wrench designs of the present invention. The end of handle portion  114  has an air inlet port  122  for connection to a compressed air supply by various means known in the art. An actuation button is located between housing  120  and air inlet port  122 , which allows the operator to actuate the pneumatic motor, the drive mechanism, and the ratchet mechanism  116 . This actuator may be a button as shown, a lever, or any other type of throttle valve activating device known and used in the art. 
     Referring to FIG. 4 there is shown a disassembled view of the first preferred embodiment of the present invention. The drive mechanism is comprised of a crank  150  and a drive bushing  148  which fits within head portion  112 , when assembled. Drive bushing  148  fits within a recess formed in yoke  118 . Crank  150  is rotated by a pneumatic motor (not shown), which in turn causes drive bushing  148  to revolve and yoke  118  to reciprocate. 
     The ratchet mechanism, shown generally as  116  in FIG. 3, is comprised of a ratchet body  154 , one or more pawls  160 , a drive square  158 , and a shift lever  140 . Ratchet body  154  has a first groove  155  at the upper end of ratchet body  154 , and a second groove  156  formed at the lower end of ratchet body  154 . Shift lever  140  allows for selection of the direction of rotation of drive square  158  and any socket affixed to drive square  158 . Ratchet mechanism  116  fits within yoke  118  to allow for rotation of drive square  158 . 
     Also provided with the present design are replaceable wear washers  144 ,  146  and  152 . Wear washers  144 ,  146  and  152  are provided along the primary wear surfaces of the ratchet wrench head of the present invention, and thus prevent head portion  112  from becoming worn. Thus, wear washer  144  is placed on the outer surface of ear  111 , wear washer  146  is placed on the inner surface of ear  111  and wear washer  152  is placed on the outer surface of ear  113 . Wear washers  144 ,  146  and  152  are replaced as necessary to prevent damage to head portion  112 . 
     As shown in FIG. 5, the ratchet wrench of the present invention includes a tensioning mechanism that creates the required friction within head mechanism  116 . This friction is commonly referred to in the art as head tension or simply tension. In this embodiment, and example of such a tensioning mechanism is shown as a compressed spring  164  and ball  166 , which are used to provide sufficient tension to ratchet  116 , caused by spring  164  biasing ball  166  into wear washer  146 . This creates the required head tension for ratchet mechanism  116 , containing pawl  128 , to advance the ratchet within yoke  118 , as yoke  118  moves with reciprocating motion. At least two spring  164  and ball  166  combinations are used to provide sufficient tension to ratchet  116 . The combination of spring  164  and ball  164  are held in position upon ratchet body  154  within depressions  157 . Other tensioning mechanisms may be used, such as a belleville washer, a compression spring, a compression spring and a cylindrical plunger or other friction surface, as well as any other tensioning means known and used in the art. 
     Ratchet mechanism  116  and yoke  118  are retained within head portion  112  by means of mechanical fasteners, such as snap rings  142  and  162 . Yoke  118  is placed between ears  111  and  113  of head portion  112 . Wear washers  144 ,  146  and  152  are positioned about ratchet body  154 . Snap rings  142  and  162  are then affixed within grooves  155  and  156 , respectively, completing assembly of the ratchet head. Because snap rings  142  and  162  are positioned externally, ears  111  and  113  are prevented from spreading upon the application of torque to head portion  112 . This prevents malfunctioning of ratchet mechanism  116 , caused by the decrease in head tension, thus causing ratchet mechanism  116  not to advance within yoke  118  and a loss of the ratcheting action between the teeth formed on pawl(s)  160  and the teeth formed on the inner surface of yoke  118 . 
     As this ratchet head design externally retains the ratchet mechanism by snap rings  142  and  162  which are in rotational contact with wear washers  114  and  152  respectively, wear washers  144  and  152  may be utilized to prevent wear to ratchet head portion  112 . Since wear washers  144  and  152  are replaceable, damage to head portion  112  is decreased and the life of the tool is increased. Wear washer  146  is in contact with balls  166  of the rotating tensioning means, and therefore also helps to decrease wear to head portion  112 . 
     Referring now to FIGS. 7,  8  and  9 , there is shown a second preferred embodiment of the present invention. The second preferred embodiment, and the third preferred embodiment described below are similar to the first embodiment in having similar tensioning mechanisms, drive mechanisms, housings, handle portions, actuation button, and air inlet ports. As such, these similar aspects are not discussed in relation to the additional embodiments of the present invention. 
     Second preferred embodiment  200  includes a ratchet head  212  having ears  211  and  213 . Within ears  211 ,  213  are formed bores for placement of a ratchet mechanism  216  as described below. Inserted between ears  211  and  213  is yoke  218 . Yoke  218  has a bore formed within it having teeth formed about the circumference of the bore. Yoke  218  also has a drive bushing journal for engagement with drive bushing which imparts force on yoke  218  from the crank, as shown in FIG. 4, causing yoke  218  to swivel or reciprocate. Ratchet mechanism  216  comprises a ratchet body  254 , at least one pawl (not shown), and drive square  258 . A shift lever such as is shown in FIG. 4 designated as  140 , is inserted within the bore formed within ratchet body  254 . Ratchet body  254  has a groove  255  formed at the upper end of ratchet body  254  and a flange  264  which extends radially outwardly from the lower end of ratchet body  254  adjacent drive square  258 . 
     When assembled ratchet mechanism  216  is inserted within the bores formed in ear  211 , yoke  218  and ear  213 . Wear washers  252 ,  246  and  244  are position about ratchet mechanism  216  along the areas of contact between ratchet mechanism  216 , and ratchet head  212 . Wear washers  252 ,  246  and  244  are replaceable and decrease wear on the ratchet head  212 . Ratchet mechanism  216  is retained within ratchet head  212  by placing external snap ring  242  within groove  255  formed on ratchet mechanism  216 . 
     Although the second embodiment of the present invention is shown and described having the radially extending flange  264  on the lower portion of ratchet mechanism  216 , flange  264  may be formed on the upper portion of ratchet mechanism  216  by inverting the position of drive square  258  and flange  264  to the upper end of ratchet body  254 . In turn, groove  255  would be formed on the lower portion of ratchet mechanism  216  for acceptance of snap ring  242 . Reversing the positions of flange  264  and groove  255  would still allow for externally capturing ratchet mechanism  216  within ratchet head  212 . 
     As ratchet mechanism  216  is externally captured within ratchet head  212  on the upper end by snap ring  242 , and the lower end by flange  264 , the ears  211 ,  213  of ratchet head  212  cannot readily spread apart. As described in association with the first preferred embodiment, preventing ears  211 ,  213  from spreading inhibits malfunction of the ratchet action of wrench  200 . 
     Referring now to FIGS. 10 through 12, there is shown a third preferred embodiment of the present invention shown generally at  300 . Ratchet design  300  includes a ratchet head portion  312  having ears  311  and  313 . Ears  311  and  313  each have a bore formed therein for acceptance of a ratchet mechanism  316 . Positioned between ears  311 ,  313  is yoke  318 , which in turn has a bore formed therein having teeth formed about the circumference of said bore. 
     As illustrated in FIGS. 11 and 12, ratchet design  300  also includes a ratchet mechanism  316 . Ratchet mechanism  316  includes a ratchet body  354 , a slot for accepting at least one pawl (not shown), and a drive square  358 . Like the first and second preferred embodiments of the present invention, a shift lever is placed within a bore formed within ratchet body  354  for selecting the direction of rotation of drive square  358 . A groove  355  is formed on the upper portion of ratchet body  354 . 
     In assembling ratchet design  300 , ratchet mechanism  316  is placed through ear  313  and within the bore formed in ear  311  and the bore formed within yoke  318 . The lower portion of ratchet body  354  is positioned adjacent to the bore formed in ear  313 . Wear washer  346  is placed about ratchet mechanism  316  along the inner surface of ear  311 , while wear washer  344  is placed around ratchet mechanism  316  along the outer surface of ear  311 . Snap ring  342  is placed within groove  355  to retain ratchet mechanism  316  within the ratchet head portion  312  and complete the assembly. Because ratchet mechanism  316  is externally retained by snap ring  342 , loss of head tension is deterred because, as discussed in previous embodiments, the tensioning mechanisms are captured between the ratchet body  354  and wear washer  346  and held there by external snap ring  342 . Spreading of ears  311  and  313 , while not prevented as in other embodiments, does not effect head tension, and in turn functioning of the ratchet wrench  300 . Further, as with the previous embodiments, use of replaceable wear washers  344  and  346  along the wear surfaces decreases wear and damage to ratchet head portion  312  itself, increasing the life of the tool and decreasing tool maintenance costs. 
     As shown in FIGS. 3 through 12, yoke  118 ,  218  and  318  of the three preferred embodiments of the present invention may be provided with a lubrication port for application of lubricants, such as grease for example, to the area of engagement between the teeth formed on the inner surface of yoke  118 ,  218  or  318 , and the teeth formed on the ends of the pawl(s) of the ratchet mechanism. Further, lubrication port may be provided with more than one outlet, with one of these outlets allowing for the application of lubricants to the drive mechanism, i.e. the ball and crank, of the powered ratchet wrench. 
     Although the principles, preferred embodiments and preferred operation of the present invention have been described in detail herein, this is not to be construed as being limited to the particular illustrative forms disclosed. They will thus become apparent to those skilled in the art that various modifications of the preferred embodiments herein can be made without departing from the spirit or scope of the invention as defined by the appended claims.