Abstract:
A reversible ratchet device is provided as a low-torque application wrench in the form of an elongated body carrying a ratchet mechanism thereon, the ratchet mechanism being operable under low-torque conditions such as are present with initial driving or final loosening of a workpiece. The device includes the ratchet mechanism carried directly on the body, both being co-axially rotatable with each other and with the workpiece.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to ratchet wrenches and, in particular, to an elongated, extension wrench having a low-torque ratchet mechanism carried thereon. 
       BACKGROUND 
       [0002]    Currently, a known issue for driving bolts or securing nuts is access to a periphery of the nut or the head of the bolt. As a mere example, the engine compartment of a passenger automobile and each of the components therein are designed and laid-out to maximize the use of the space within the engine compartment. The result of such engineering is that access to workpieces securing the various components either to the car or to the other components is limited. Accordingly, it has long been known to use an extension to reach the workpieces. 
         [0003]    A common extension is generally elongated and rod-like. During use, a distal end of the extension is mated with an apparatus known as a socket driver, while a proximal end of the extension is mated with a ratchet wrench. Generally speaking, the socket driver may be mated with the ratchet wrench, yet such an arrangement would render the socket driver unable to reach the desired workpiece. Hence, the extension distal end has structure like that of the ratchet wrench so that the distal end may mate with the socket driver in order to reach the workpiece. Likewise, the proximal end includes structure like that of the socket driver so that the proximal end is mateable with the ratchet wrench for providing torque to the workpiece. 
         [0004]    As a ratchet wrench, rotation thereof in a first direction operatively is capable of providing drive torque, while counter-rotation in a second direction opposite the first merely allows the ratchet mechanism to ratchet over a component, commonly a spring-biased pawl or pawls. In many forms, it is known for the ratchet wrench to be selectively engageable to select a drive direction and a ratchet direction. Typically this is achieved by providing a lever or similar mechanism on the ratchet wrench, reversal of the lever serving to reverse the drive and ratchet directions by adjusting a position of the pawl or pawls. 
         [0005]    The above-described extension, used with or without the ratchet wrench, nonetheless has drawbacks. For initial driving of a workpiece, or for final removal of the workpiece, it is typical for the workpiece to rotate with very little torque applied. As a specific common example, a nut will often spin freely on a threaded bolt shank until the nut comes in contact with something else, at which time increasing amounts of torque are required to tighten the nut on the bolt. The extension may be necessary for driving or removing the workpiece, even when the workpiece is able to move with small amounts of torque, due to the location of the workpiece. 
         [0006]    In using the extension with workpieces that require small torque amounts for at least some amount of rotations or turn, the extension is simply rotated by fingers applied directly to the extension. For the wratchet wrench, some amount of resistance must be offered by the workpiece in order for the ratchet wrench to ratchet; the workpiece that is able to rotate with small torque amounts in one desired direction usually will rotate in the opposite direction with similarly small torque amounts. Therefore, the resistance required for the ratchet wrench to ratchet is not present; alternating movements of rotation and counter-rotation by the ratchet wrench simply serve to rotate the workpiece back and forth. 
         [0007]    Accordingly, a user typically needs to maintain at least one hand on the extension at all times to maintain contact with the workpiece. The user then also needs to turn and release the extension with their other hand. So, in one form, a user grasps the extension connected with the workpiece with a first hand and then rotates the extension to some degree. Continuing, the user then grasps the extension with the other hand while releasing the first hand, which is repositioned for a subsequent rotation. The second hand is released as the first hand begins the subsequent rotation, and so on and so forth until the workpiece is either removed or reaches the point of requiring a higher torque. In a variation of this, a user may attempt to use the ratchet wrench with the extension by using one hand to rotate and counter-rotate the ratchet wrench while the other hand applies sufficient frictional resistance to the extension so that the rotation of the ratchet wrench in the drive direction is permitted with drive torque transmitted through the extension to the workpiece, while counter-rotation of the extension along with the ratchet wrench is resisted or prevented by the user&#39;s hand, thus providing the torque sufficient for the ratchet wrench to successfully ratchet. 
         [0008]    Accordingly, there has been a need for an improved extension and, a need for ratchet wrenches for low resistance-torque applications. 
       SUMMARY 
       [0009]    In accordance with an aspect, an extension device for providing torque to a workpiece is disclosed, the extension including an elongated body having a first end proximate a user during operation for receiving torque and having a second end distal a user during operation for transmitting the torque, and a ratchet mechanism disposed around the body and located on the first end, the ratchet mechanism having a grip portion for manual manipulation, the ratchet mechanism transmitting torque to the body for when the grip portion is rotated in a drive direction, and the ratchet mechanism allowing the grip portion to slip relative to the body when rotated in a ratchet direction opposite the drive direction. 
         [0010]    In some forms, the extension device rotates around an axis, and the workpiece and grip portion rotate around the same axis. 
         [0011]    In some forms, the elongated body is a unitary and integral component. 
         [0012]    In some forms, the second end includes structure for engaging and securing with a socket driver for transmitting torque to the workpiece. 
         [0013]    In some forms, the ratcheting mechanism is a low-torque ratchet mechanism. The second end may include structure for engaging with and securing with a secondary wrench for high-torque application. 
         [0014]    In some forms, the ratchet mechanism includes a reversing lever for selecting drive and ratchet directions, the grip portion is formed on a first component of the ratchet mechanism, and the reversing lever is a second component of the ratchet mechanism. 
         [0015]    In some forms, the ratchet mechanism includes a pawl assembly including at least a ratchet gear carried on and secured with the body, at least one pawl, and a bias member for biasing the pawl into engagement with the ratchet gear. 
         [0016]    In some forms, the ratchet gear and body may have non-circular cooperating engagement structure to prevent relative rotation therebetween. The cooperating engagement structure may include a flat or a lobe. 
         [0017]    In some forms, the pawl assembly may include a pair of pawls, and the reversing lever is rotatable around the axis of the body, rotation of the reversing lever shifting one of the pawls out of engagement with the ratchet gear and permitting one of the pawls to shift into engagement with the ratchet mechanism. 
         [0018]    In some forms, the reversing lever is in abutment with the first component and rotatably carried on the body. 
         [0019]    In some forms, the reversing lever is rotatably carried on the first component. The reversing lever may include a ring, and the first component may include a ring, the lever ring being disposed around the first component ring. 
         [0020]    In some forms, extension device further includes positioning structure on the reversing lever and the first component for providing defined positions therebetween. The reversing lever may include a ring, the first component may include a ring, the lever ring being disposed around the first component ring, and the positioning structure may be formed on the rings. 
         [0021]    In some forms, the first component includes a cavity for receiving the pawl assembly. The reversing lever may encloses the cavity. The ratcheting mechanism may further include a cover plate enclosing the cavity. 
         [0022]    In some forms, the extension device further includes a retainer for securing the ratcheting mechanism on the body. The body may include a channel, and the body and ratcheting mechanism may include cooperating engagement structure for mounting the ratcheting mechanism thereon, the retainer being a C-shaped clip securable in the channel and against the body cooperating engagement structure for securing the ratcheting mechanism on the body. The the cooperating engagement structure may include a flat or a lobe. The cooperating engagement structure may be non-circular. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    In the Figures,  FIG. 1  is a side elevation view of a first form of a low-torque application extension of the present invention including an on-board and integrated ratchet drive mechanism; 
           [0024]      FIG. 2  is a exploded perspective view of the extension of  FIG. 1 ; 
           [0025]      FIG. 3  is a second exploded perspective view of the extension of  FIG. 1 ; 
           [0026]      FIG. 4  is a cross-sectional view of the extension taken through the line  4 - 4  of  FIG. 1 ; 
           [0027]      FIG. 5  is a second cross-sectional view of the extension taken through the line  5 - 5  of  FIG. 1 ; 
           [0028]      FIG. 6  is a side elevation view of a second form of a low-torque application extension of the present invention including an on-board and integrated ratchet drive mechanism; 
           [0029]      FIG. 7  is an exploded perspective view of the extension of  FIG. 6 ; 
           [0030]      FIG. 8  is a second exploded perspective view of the extension of  FIG. 6 ; 
           [0031]      FIG. 9  is a cross-sectional view of the extension taken through the line  9 - 9  of  FIG. 6 ; 
           [0032]      FIG. 10  is a second cross-sectional view of the extension taken through the line  10 - 10  of  FIG. 6 ; 
           [0033]      FIG. 11  is a side elevation view of a third form of a low-torque application extension of the present invention modifying the second form of  FIG. 6 ; 
           [0034]      FIG. 12  is an exploded perspective view of the extension of  FIG. 11 ; 
           [0035]      FIG. 13  is a second exploded perspective view of the extension of  FIG. 11 ; and 
           [0036]      FIG. 14  is a cross-sectional view of the extension of taken through the line  14 - 14  of  FIG. 11   
       
    
    
     DETAILED DESCRIPTION 
       [0037]    Referring to the  FIGS. 1-5 , a first form of a reversible, low-profile, low-torque application ratchet extension  10  of the present invention is illustrated. As described, the extension  10  permits a user to access a workpiece that would otherwise be difficult to access, in the manner known for a conventional extension. Additionally, the extension  10  includes a distal end  12  having structure  14  for releasably engaging with a socket driver (not shown), and includes a proximal end  16  having structure  18  for releasably engaging with a ratchet wrench (not shown). As will be described in greater detail below, the extension  10  further includes a reversible ratchet mechanism  20  allowing the user to select a drive direction and accompanying ratchet direction, the ratchet mechanism  20  being constructed for low torque applications. Thus, the extension  10  is operable with standard socket drivers for engaging and rotating workpieces in a drive direction, including when the workpieces have limited access and/or when the workpieces provide little resistance to support the ratcheting of the ratchet wrench. 
         [0038]    The extension  10  includes a body  30  similar in construction to a conventional extension. More precisely, the body  30  is generally elongate and has a circular cross-section of varying diameter. The proximal end structure  18  includes a socket opening  32  for receiving a post of a ratchet wrench (not shown). As the extension  10  includes the ratchet mechanism  20 , use of the extension in a ratcheting manner does not require the ratchet wrench. The distal end structure  14  is generally a post  34  that permits connection with a socket driver (not shown), the socket driver engaging with a workpiece for applying torque thereto. As the socket driver is otherwise operable with a ratchet wrench as well, the socket driver includes a socket opening operatively identical in construction as the socket opening  32  for receiving the post  34 . 
         [0039]    The extension  10  is modified or altered with respect to a conventional extension by carrying and by being operable via the ratchet mechanism  20 . In brief terms, the ratchet mechanism  20  includes a ratchet housing  40  with an outer surface  42  grippable by a user for use of the extension in a ratchet-drive manner, and the ratchet mechanism  20  includes a reversing lever  44  for selection of a drive direction for the extension  10 . Therefore, upon selection of a drive direction, a user gripping the housing  40  and rotating the housing  40  in one direction provides drive torque through the extension  10  as a whole and to a workpiece. Rotation of the housing  40  in the opposite direction allows the ratchet mechanism  20  to skip or ratchet so that the extension body  30  does not rotate, and no torque is provided to the workpiece. 
         [0040]    Note, it is recognized that, generally speaking, the extension  10  is considered to provide torque to the socket driver connected with the distal end structure  14 , and the socket driver transmits the torque to a workpiece. For simplicity&#39;s sake and in recognizing that the extension  10  distal end structure  14  may be constructed to engage directly with a workpiece, discussion of providing torque from the extension  10  to a workpiece is in intended to refer to such without distinguishing whether an intermediate structure is present. 
         [0041]    As can best be seen in  FIG. 3 , a ratchet gear  46  is provided in the ratchet mechanism  20 . The ratchet gear  46  includes a generally circular and toothed outer periphery  48  along its radial surface. The ratchet gear  46  is ring-like having a central opening  50  for receiving the body  30  therein. The opening  50  is generally circular so that the ratchet gear  46  is largely annular in a proper sense, except that a flat  52  extends inwardly. 
         [0042]    The ratchet gear  46  is received over a portion of the body  30  having a corresponding structure. That is, the body  30  has a portion  30 a having a generally circular or cylindrical outer surface  54  with a flat  56  corresponding to the ratchet gear flat  52 . The ratchet gear  46  is positioned and closely received on the extension  10  with the respective flats  52  and  56  mating so that rotation of the extension  10  rotates the ratchet gear  46  and vice versa. 
         [0043]    The housing  40  is positioned around the ratchet gear  46  and includes a reversible pawl assembly  60  for selecting drive and ratchet directions via engagement with the ratchet gear  46 . Turning to  FIG. 4 , the housing  40  includes an opening  62  having three distinct portions: first and second portions  62   a  and  62   b  are formed as pawl pockets for receiving first and second pawls  64   a  and  64   b,  while a third portion  62   c  is generally circular and is positioned closely around the teeth of the ratchet gear  46 . 
         [0044]    In  FIG. 4 , the first pawl  64   a  is engaged with the ratchet gear  46  and, thus, a drive direction D and ratchet direction R are selected, as shown by the arrows labeled as such. The first pawl  64   a  is biased by a resiliently compressible member in the form of a first coil spring  66   a  into engagement with the ratchet gear  46  or, viewed another way, into engagement with an inwardly sloping wall  68   a  formed on the first pawl pocket  62   a,  which in turn directs the first pawl  64   a  into engagement with the ratchet gear  46 . Thus, when the housing  40  is rotated in the drive direction D, the first pawl  64   a  is pressed between the sloping wall  68   a  and the ratchet gear  46  to lock the housing  40  with the ratchet gear  46 . When the housing  40  is rotated in the opposite direction, the ratchet direction R, only the spring  66   a  provides any force to maintain the first pawl  64   a  in engagement with the ratchet gear  46 : to the degree rotation of the ratchet gear  46  and extension in the ratchet direction R provide torque resistance, the teeth of the ratchet gear  46  cause the first pawl  64   a  to compress the first spring  66   a  and, in a sense, the teeth of the ratchet gear  46  act to cam the first pawl  64   a  out of engagement. The first pawl  64   a  will shift a sufficient amount until the respective teeth thereof are able to slip, or ratchet, over the teeth of the ratchet gear  46 . 
         [0045]    While the ratcheting ability is understood by one skilled in the art, it is simply noted that such depends on the relative use of springs  66  with a low spring constant (a “light” spring), and teeth for both the pawls  64  and the ratchet gear  46  that are small relative to the diameter of the ratchet gear  46 . 
         [0046]    As can be seen, the second pawl  64   b  is held out of engagement with the ratchet gear  46  by a post  70 . Were the reversing lever shifted  44 , the drive direction D and the ratchet direction R would be reversed, the second pawl  64   b  would be shifted into engagement like is shown in  FIG. 4  for the first pawl  64   a,  and the first pawl  64   a  would be shifted out of engagement like is shown in  FIG. 4  for the second pawl  64   b.    
         [0047]    The post  70  is carried on the reversing lever  44 . In the present configuration, the post  70  is shown as somewhat trapezoidal in order to have a first ramp  72   a  for contacting a first chamfer  74   a  formed on the first pawl  64   a,  and a second ramp  72   b  for contacting a second chamfer  74   b  formed on the second pawl  64   b.  As the reversing lever  44  is rotated, discussed below, the post  70  is shifted relative to the housing  40  and the pawl assembly  60  so that the first ramp  72   a  either contacts or moves away from the first chamfer  74   a,  while the second ramp  72   b  does the opposite with respect to the second chamfer  74   b.  In this manner, the reversing lever  44  serves to force a pawl  64  (such as second pawl  64   b ) out of engagement so that the other pawl  64  (first pawl  64   a ) is forced into engagement with the ratchet gear  46  by its spring  66  (i.e., first spring  66   a ). 
         [0048]    A detent mechanism  76  is provided for generally maintaining the reversing lever  44  and housing  40  in defined positions for the selected drive and ratchet directions D, R. The reversing lever  44  generally abuts the housing  40  and rotates generally co-axially therewith around the body  30 . The housing  40  includes a blind recess or bore  78  for receiving a plunger  80  and spring (not shown) that biases the plunger  80  towards the reversing lever  44 . The reversing lever  44 , in turn, has a recess  82  for receiving a tip  84  of the plunger  80 . The recess  82  is slightly arcuate to account for the small relative rotation between the reversing lever  44  and the housing  40  when the reversing lever  44  is rotationally shifted between positions to select the drive and ratchet directions D, R. The recess  82  includes two distinct positions, such as having a pair of slight cups  82   a  formed therein for receiving the plunger tip  84 , and the ends of the recess  82   b  provide stops for limiting rotation of the reversing lever  44  relative to the housing  40 . 
         [0049]    A retainer  90  is provided for maintaining the ratchet mechanism  20  on the body  30 . In the illustrated embodiment, the retainer  90  is generally a C-shaped snap ring, and the body  30  includes a channel  92  cut into the surface thereof proximate portion  30   a.  The snap ring  90  includes enlarged portions  90   a  which are received on the flat body  56  to prevent rotation of the snap ring  90 . 
         [0050]    It should be noted that the extension  10  provides a low profile. In a preferred form, the portion  30   a  on which the ratchet mechanism  20  including the grip surface  42  is secured is of a reduced diameter in comparison with proximal end structure  18 . Thus, a shoulder  96  on the body  30  between proximal end structure  18  and the portion  30   a,  the ratchet mechanism  20  being secured between the shoulder  96  and the snap ring retainer  90 . It should also be noted that the housing opening  62  passes through the housing  40  for the third, circular portion  62   c,  while the pawl pockets  62   a,    62   b  do not pass through. The pawl pockets  62   a,    62   b  thus somewhat define a cavity  63  in which the pawls  64  and the springs  66  are located. The reversing lever  44 , in abutment with the housing  40 , thus serves as a cover for the cavity. 
         [0051]    Turning now to  FIGS. 6-10 , a second form of a reversible, low-profile, low-torque application ratchet extension  100  of the present invention is illustrated. As for the above-discussed extension  10 , the second form of an extension  100  includes a body  130  having ends  112 ,  116  for connecting with a workpiece, a ratchet wrench, and/or a socket driver (not shown). A ratcheting mechanism  120  is secured with the body  130  via a retainer  190 . The ratcheting mechanism  120  includes a housing  140  with a grip surface  142  and including a reversing lever  144  for selecting drive and ratchet directions D, R. The reversing lever  144  shifts pawls  164  into and out of engagement with sloping walls  168  formed on pawl pockets  162   a,    162   b  of an opening  162  in the housing  140  positioned around a ratchet gear  142 . The ratchet gear  142  is mated with the body  130  to prevent or restrict relative rotation therebetween, preferably via respective flats  152 ,  156  therebetween. 
         [0052]    As the operation and many of the components of the second extension  100  are generally the same as the first extension  100 , the differences shall be highlighted. As can be seen, the pawl pockets  162   a,    162   b  are part of a cavity  163  that is oriented towards the proximal end  116 , while the first extension  10  has such cavity  63  facing the distal end  12 . To enclose the cavity  163 , a cover plate  167  is provided. While this cover plate  167  is an additional component, it can be secured to the housing  40  to reduce the ingress of contaminants into the cavity  163  in comparison with the form of the first extension  10 . It should also be noted that slot  169  ( FIG. 8 ) is added to the housing  140  to allow the post  170  of the reversing lever  144  to pass through the housing  140  and into the cavity  163 . 
         [0053]    Additionally, the use of the cover plate  167  allows a reduction in the size of the reversing lever  144  in comparison to the reversing lever  44 , amongst other features. As can best be seen in  FIGS. 6 ,  8 , and  10 , the reversing lever  144  is carried directly on the housing  140 . Towards this end, the housing  140  includes a ring  141  extending distally away from a body portion  143 . The reversing lever  144  includes a ring  145  and a tab  147  extending radially therefrom, the reversing lever ring  145  being positioned around the housing ring  141 . The tab  147  is enlarged relative to the lever ring  145 , but preferably no larger in radial extent from the extension axis of rotation, so that rotation of the reversing lever  144  to select drive and ratchet directions is ergonomically easy for a user. 
         [0054]    In the illustrated form, the reversing lever  144  and housing  140  include a plunger  180  and a cupped recess  182 , like that discussed for the first extension  10 . However, additionally or in the alternative, the rings  141 ,  145  of the housing  140  and reversing lever  145 , respectively, may also provide distinct positions and stops for relative rotation therebetween. As can be seen, the lever ring  145  includes tabs  149 , while the housing ring  141  includes key ways  151  for receiving the tabs  149 . With reference to  FIG. 10 , the cooperation between tabs  149  and key ways  151  can be seen. The tabs  149  and key ways  151  can be constructed as guides for minimizing friction between the reversing lever  144  and housing  140 , as well as can be constructed with appropriate contours such that they operate to lock and/or provide stops, such as by frictionally engaging or by having a ramp to a flat, then a depression, (not shown). 
         [0055]    A further form of a reversible, low-profile, low-torque application ratchet extension  200  of the present invention is illustrated in  FIGS. 11-14 . The extension  200  is similar in many respects to the extension  100  and includes a body  230  having ends  212 ,  216  for connecting with a workpiece, a ratchet wrench, and/or a socket driver (not shown). A ratcheting mechanism  220  is secured with the body  230  via a retainer  290 . The ratcheting mechanism  220  includes a housing  240  with a grip surface  242  and includes a reversing lever  244  for selecting drive and ratchet directions D, R. The reversing lever  244  shifts pawls  264  into and out of engagement with sloping walls  268  formed on pawl pockets  262   a,    262   b  of an opening  262  in the housing  240  positioned around a ratchet gear  242 . The pawl pockets  262   a,    262   b  are part of a cavity  263  oriented towards the proximal end  216 , the cavity  263  closed by a cover plate  267 , and slot  269  ( FIG. 12 ) allows post  270  of the reversing lever  244  to pass through the housing  240  and into the cavity  263 . 
         [0056]    The housing  240  includes a ring  241  extending distally away from a body portion  243 , and the reversing lever  244  includes a ring  245  and a tab  247  extending radially therefrom, the reversing lever ring  245  being positioned around the housing ring  241 . The tab  247  is enlarged relative to the lever ring  245 , but preferably no larger in radial extent from the extension axis of rotation, so that rotation of the reversing lever  144  to select drive and ratchet directions is ergonomically easy for a user. 
         [0057]    The reversing lever  244  and housing  240  include a plunger  280  and a cupped recess  282 . The rings  241 ,  245  of the housing  240  and reversing lever  245 , respectively, may also provide distinct positions and stops for relative rotation therebetween. As can be seen, the lever ring  245  includes tabs  249 , while the housing ring  241  includes key ways  251  for receiving the tabs  249 . 
         [0058]    Turning towards the differences between the extension  200  of  FIGS. 11-14  and the extension  100  of  FIGS. 6-10 , it is noted that the extension  100  includes the ratchet gear  142  mated with the body  130  to prevent or restrict relative rotation therebetween. To achieve such, for the extension  100 , the ratchet gear  142  and body  130  have respective flats  152 ,  156  therebetween. For the extension  200  of  FIGS. 11-14 , the body  230  and ratchet gear  242  again have cooperating or abutting structure to achieve such; however, the body  230  is provided with a pair of diametrally positioned flats  256   a,    256   b,  while the ratchet gear  242  is provided with a pair of diametrally positioned surfaces  252   a,    252   b  having a lobed shape and, preferably, having a pair of lobes  253  on each surface  252   a,    252   b.    
         [0059]    Additionally, it is noted that the housing  240  includes cut-outs  271  passing therethrough. The cut-outs  271  are aligned with the key ways  251  and simplify manufacturing and assembly. 
         [0060]    As described, the forms of extensions  10 ,  100 ,  200  provide an elongated extension as is conventionally known for accessing workpieces small or low clearance locations, obviate the need for a separate ratchet wrench as the ratchet mechanism is carried on the extension, and provide such ratchet mechanism in a low-torque form for low-torque applications. As described, the extensions also permit the use of a separate ratchet wrench and conventional socket drivers by having cooperating engagement structure therefor, which allows the secondary ratchet wrench to be used in the event high torque is required. The extensions  10 ,  100 ,  200  are operable by gripping a portion thereof, such as manually grasping grip portions  42 ,  142 ,  242 , and rotating and counter-rotating in drive and ratchet directions D, R, the rotation being about a common axis of rotation for the extension  10 ,  100 ,  200  itself as well as a common axis for a workpiece. To permit and facilitate ease of use, the ratchet mechanism is carried near the proximal end, during use, of the extension, as is a reversing lever for selecting and changing the drive and ratchet directions. 
         [0061]    While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims.