Abstract:
An adjustable wrench includes: a head having a first fixed jaw; a handle extending away from the head and having a longitudinal axis; a second jaw selectively positionable with respect the first jaw; an adjustment mechanism comprising a rotatable shaft, an actuator, and a gear train operatively coupling the shaft to the second jaw; the shaft having an external spiral groove and disposed at least partially in the handle; the actuator slidable relative to the handle and engaging the groove; first and second flanges spaced from one another; and a retainer disposed between the flanges and engaging the shaft so as to limit movement of the shaft parallel to the handle longitudinal axis in two directions via abutment with the first and second flanges. Such a wrench may have a proof torque of at least the minimum level set forth in ASME B107.8, 2003 revision.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention is directed generally to hand tools known as adjustable wrenches, and more particularly to an adjustable wrench that employs a slide-based adjusting mechanism.  
         [0002]     Adjustable wrenches are generally considered more convenient to use than conventional open-end jaw wrenches because they are adjustable over a range of sizes and therefore adaptable to a variety of workpiece sizes. Conventional adjustable wrenches include a fixed jaw and a moveable jaw, with movement of the moveable jaw controlled by rotation of an externally accessible adjusting worm gear. The user simply rotates the worm gear, typically by engaging the knurled outer surface thereof with their thumb, to move the moveable jaw toward or away from the fixed jaw. High quality examples of such wrenches are sold under the brand name “CRESCENT” by Cooper Industries, Inc. of Houston, Tex.  
         [0003]     While such wrenches have gained wide acceptance, they do not always provide the desired operational “feel” and are sometimes difficult to adjust in situ. Accordingly, alternative approaches to adjustable wrenches have been proposed. For example, U.S. Pat. No. 3,901,107 to Halls discloses an adjustable wrench that uses a “tape drive” mechanism to control movement of the moveable jaw. Likewise, U.S. Pat. No. 3,640,159 to Halls et al discloses an adjustable wrench that controls the movement of the moveable jaw via a slide-based adjusting mechanism. However, these alternative designs have not proven entirely satisfactory for various reasons. As such, there remains a need for alternative designs for adjustable wrenches, advantageously designs that are robust yet simple to use.  
       SUMMARY OF THE INVENTION  
       [0004]     In one embodiment, the present invention provides an adjustable wrench, comprising: a head having a first fixed jaw; a handle extending away from the head and having a longitudinal axis; a second jaw selectively positionable with respect the first jaw; an adjustment mechanism controlling the positioning of the second jaw and comprising a rotatable shaft, an actuator, and a gear train operatively coupling the shaft to the second jaw; the shaft having an external spiral groove and disposed at least partially in the handle and generally parallel to the handle longitudinal axis; the actuator slidable relative to the handle and engaging the groove; first and second flanges spaced from one another; and a retainer disposed between the flanges and engaging the shaft so as to limit movement of the shaft parallel to the handle longitudinal axis in two directions via abutment with the first and second flanges. The first and second flanges may be disposed between the spiral groove and the gear train. The shaft may be substantially fixed against longitudinal movement via the first flange, the second flange, and the retainer. The spiral groove may trace a helix. The gear train may comprise a rotatable worm gear operatively disposed between the shaft and the second jaw. A biasing member may bias the worm gear toward the shaft, and the biasing member may comprise a discrete spring. A retaining cap may be disposed so as to constrain axial movement of the worm gear. The first jaw may extend in a first direction generally opposite the handle; with the head further comprising a pair of spaced, generally parallel, sidewalls distal from the first jaw; with a recess defined between the sidewalls; wherein the gear train comprises a worm gear disposed substantially within the recess and having a rotational axis; the recess having a cross-sectional dimension D measured in a direction Z that is both normal to the rotational axis and generally perpendicular to the first direction; wherein the sidewalls both have a thickness in direction Z of about 25% D or more. A debris shield may be associated with the shaft, and may circumferentially surrounds the shaft. The debris shield may include a spiral slot, the spiral slot and the spiral groove having different pitches, wherein the actuator engages the spiral groove and the spiral slot. A wrench with one or more of these features may have a proof torque of at least the minimum level set forth in ASME B107.8, 2003 revision, when tested according to the method set forth in the ASME standard. A related method is also described.  
         [0005]     In another embodiment, the present invention provides an adjustable wrench, comprising: a head having a first fixed jaw extending in a first direction, a pair of spaced, generally parallel, sidewalls distal from the first jaw, and a recess defined between the sidewalls; a handle extending away from the head in a second direction generally opposite the first direction and having a longitudinal axis; a second jaw selectively positionable with respect the first jaw; an adjustment mechanism controlling the positioning of the second jaw and comprising a shaft, an actuator, and a gear train operatively coupling the shaft to the second jaw; the shaft disposed at least partially in the handle and having an external spiral groove; the actuator slidable along the handle and engaging the groove; wherein the gear train comprises a worm gear rotatable about a rotational axis and disposed in the head recess; wherein the recess has a cross-sectional dimension D measured in a direction Z that is both normal to the rotational axis and generally perpendicular to the first direction; wherein the sidewalls both have a thickness in direction Z of about 25% D or more. Other features discussed above may be included in such a wrench, alone or in combination. A related method is also described. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  shows one of many embodiments of an adjustable wrench constructed in accordance with the present invention, with the jaws in the fully open position.  
         [0007]      FIG. 2  shows a reverse perspective view of one of many embodiments of a moveable jaw.  
         [0008]      FIG. 3  shows a partially exploded view of the wrench body of  FIG. 1 .  
         [0009]      FIG. 4  shows a horizontal cross-section of the wrench of  FIG. 1 .  
         [0010]      FIG. 5  shows a partial cutaway side view of the wrench of  FIG. 1  with some components removed for clarity and the actuator moved to an intermediate position corresponding to the moveable jaw at a position between fully open and fully closed.  
         [0011]      FIG. 6  shows more detail of  FIG. 4 .  
         [0012]      FIG. 7  shows an exploded view of the shaft portion of the adjustment mechanism, actuator, and cover plate. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]     The adjustable wrench of the present invention employs a slide actuated adjustment mechanism  70 , and includes numerous features that may be used alone or in combination to form a robust wrench which is, in some embodiments, advantageously capable of passing the proof torque test requirement of ASME B107.8 (2003).  
         [0014]     One embodiment of the wrench is shown in  FIG. 1  and generally indicated at  10 . The wrench includes a wrench body  12  with a jaw  20  moveably mated thereto. The wrench body  10  includes a head section  30 , an integrally formed handle  50 , and an adjusting mechanism  70 . The head section  30  includes a fixed jaw  32  that extends forward in direction X from one lateral side portion of the head section  30 , and a pair of opposing sidewalls  34   a , 34   b  that form a pair of recesses  40 , 46  that open to the other lateral side of the head section  30 . As explained further below, the moveable jaw  20  and a worm gear  120  are mated to the head section  30  via these recesses  40 , 46 .  
         [0015]     The moveable jaw  20  includes a conventional jaw body  22 , an intermediate web  24 , and a somewhat cylindrical lower portion  25 . The jaw body  22  may be of a conventional type known in the art, typically with a planar jaw face  23 . The jaw lower portion  25  includes a series of teeth  27  commonly collectively referred to as a rack  26 . The rack  26  is typically oriented in a direction that is perpendicular to the plane of jaw face  23 . The rack  26  is somewhat larger in cross section than the intermediate web  24 , so that the jaw  20  can be mounted in the wrench body  12  by sliding web  24  through slot  48  discussed further below. The fixed jaw  32  and moveable jaw  20  cooperate to form the working end of the wrench  10 .  
         [0016]     The handle  50  provides a convenient means to grip the wrench  10 , and also houses a portion of the adjusting mechanism  70 . The handle  50  extends away from the head section  30  in direction Y, which may be parallel to direction X or at an angle thereto. As is conventional, the handle  50  may advantageously include a hanging hole  52  toward one end. In addition, the handle  50  includes a recess  54  that is substantially covered by cover plate  56 . The recess  54  is advantageously generally rectangular and oriented so that its long dimension is parallel to the handle&#39;s longitudinal axis L. One or more threaded holes  59  may be located proximate the recess  54  for securing the cover plate  56  to the remainder of the handle  50 .  
         [0017]     An adjustment mechanism  70  controls the positioning of the moveable jaw  20  relative to the fixed jaw  32 . Broadly viewed, the adjustment mechanism  70  includes a rotatable shaft  80 , an actuator  72 , and a gear train  110  operatively connecting the shaft  80  to the moveable jaw  20 . The shaft  80  is rotatably mated to handle  50  and disposed mostly, if not entirely, in recess  54 . The shaft  80  includes a rear portion  82 , a forward portion  84 , and a middle portion  90 . The rear portion  82  typically takes the form of a simple rod-like extension, and fits into a corresponding support  64  of handle  50 . The middle portion  90  is of larger diameter, and has an spiral groove  92  in its outer surface. The spiral groove  92  extends over a substantial length of the shaft  80 , and may advantageously follow a helical path about the shaft  80 . The shaft forward portion  84  may have a stepped profile, with a proximal portion generally having a diameter matching the middle portion, and a rod-like distal portion of a smaller diameter that is typically longer in length than the rear portion  82 . The forward portion  84  is supported by two spaced apart support flanges  60   a , 60   b  that are located some distance back from the end of the shaft  80 . In addition, the forward portion  84  includes a circumferential recess  86  this is aligned with the gap  62  between the two support flanges  60   a , 60   b . A retainer  66  fits between the support flanges  60   a , 60   b  to engage this circumferential recess  86 . It is intended that the retainer  66  will abut against the corresponding support flanges  60   a , 60   b  to thereby limit the longitudinal movement of the shaft  80 . Advantageously, the retainer  66  is appropriately sized so as to just fit between the support flanges  60   a , 60   b , and thereby longitudinally fix the shaft  80  against longitudinal movement. The retainer  66  may take the form of a simple U-shaped wire of stiff material, a spring clip, or other suitable device that engages recess  86  on shaft  80 , but allows shaft  80  to rotate.  
         [0018]     An optional debris shield  100  may circumferentially surround the shaft middle portion  90  to keep external debris from entering spiral groove  92 . The debris shield  100  may take the form of a simple hollow cylinder having an inner diameter greater than the outer diameter of the middle portion of shaft  80 . The debris shield  100  includes a spiral slot  102  therethrough. In some embodiments, this spiral slot  102  may be helical, with a pitch P DS  longer than the pitch P SG  of the spiral groove  92  of shaft  80 . For example, the spiral slot  102  may have a pitch that is five to six times the pitch of the spiral groove  92 . The debris shield  100  fits loosely on the shaft  80 , and is captured between the rearmost support flange  60   b  and support  64 . The debris shield  100  helps cover, and thereby protect, the surface of the shaft  80 , so that very little, if any, of spiral groove  92  is exposed to a potentially dirty external environment. Such an arrangement is believed to help ensure long-term smooth operation.  
         [0019]     The actuator  72  may take the form of a simple external knob or button  74  of any convenient shape, with a downwardly extending drive peg  76 . The drive peg  76 , when assembled, extends through a corresponding slot  57  in cover plate  56 , through spiral slot  102  if debris shield  100  is present, and into spiral groove  92 . The actuator  72  may be retained with cover plate  56  by any suitable means. For example, drive peg  76  may have a thin flange proximate the underside of cover plate  56 , and the button portion  74  may be pinned to the peg  76 , capturing the cover plate  56  therebetween. Of course, other joining methods known in the art may be used. In addition, the button  74  may have a suitable structure on its underside to engage slot  57  in a way to prevent undesirable rotation of the button  74 . The connection method should allow the actuator  72  to traverse back and forth relative to the handle  50  in what is referred to herein as a sliding motion. Note that this sliding motion does not necessarily require contact between the sliding elements. That is, the actuator button  74  may actually be suspended above the cover plate  56  (e.g., by drive peg  76 ) while still being considered as visually “sliding along” the cover plate  56  (and thus handle  50 ). Due to the inter-engagement of drive peg  76  and spiral groove  92 , sliding the actuator  72  relative to handle  50  causes the shaft  80  to rotate.  
         [0020]     The gear train  110  converts rotational movement of the shaft  80  into translational movement of the moveable jaw  20 . The gear train  110 , in one embodiment, includes three gears, the first of which  150  rotates with the shaft  80 , and the last of which  120  engages teeth on the moveable jaw  20  to cause the jaw  20  to move back and forth. For simplicity, these gears are referred to as shaft bevel gear  150 , worm bevel gear  140 , and worm gear  120 .  
         [0021]     The worm gear  120  typically takes the form of an elongate body that is rotatably mounted in the wrench head section  30  with a seating portion  122 , a main portion  130 , and a securing portion  126 . The seating portion  122  typically takes the form of a short longitudinally extending rod-shaped portion on one end of the worm gear  120 . The seating portion is intended to extend into a corresponding hole  42  in the main body of the wrench head section  30  to help locate the worm gear  120 . The main portion  130  of worm gear  120  includes an external helical tooth  132  that directly engages teeth  27  on the moveable jaw  120  so that when the worm gear  120  turns about its rotational axis R, jaw  20  moves. The main portion  130  has a diameter larger than the seating portion  122 , thus a shoulder  124  is formed at the interface therebetween. If desired, a biasing element  121  may press against this shoulder  124  so as to urge the worm gear  120  in a direction along its rotational axis R, away from the fixed jaw  32 . This biasing element  121  may take the form of a simple coil spring disposed about the seating portion  122  and captured between the head  30  and the shoulder  124 , but any other biasing means known in the art may alternatively be used, including compressible washers, compressible foam, and the like.  
         [0022]     The securing portion  126  is disposed opposite the seating portion  122 . The securing portion  126  typically takes the form of a short rod-like section that has a stepped-down diameter towards its distal end to form shoulder  128 . The outermost portion of the securing section  126  extends into a corresponding portion of retaining cap  129 , so as to be rotatably supported thereby.  
         [0023]     Worm bevel gear  140  is mounted on the securing portion  126 , inboard of the retaining cap  129 , so as to be rotationally coupled to the worm gear  120 . The worm bevel gear  140  includes a central bore  142 , through which the securing portion  126  extends. The central bore  142  includes an internal stepped section forming shoulder  144 . It is intended that the securing portion&#39;s shoulder  128  will abut the bevel gear&#39;s shoulder  144  so as to limit the relative movement of the worm bevel gear  140  toward the main portion  130  of the worm gear  120 . Advantageously, the worm bevel gear  140  is mounted so that its gear teeth  146  face inward toward the centerline of the wrench  10 .  
         [0024]     Shaft bevel gear  150  is mounted to the forwardmost portion of shaft  80  so as to rotate therewith. The teeth  152  of shaft bevel gear  150  face forward, and engage corresponding the teeth  146  on worm bevel gear  140 . With this arrangement, rotational movement of the shaft  80  causes shaft bevel gear  150  to rotate, which causes worm bevel gear  140  to rotate, which causes worm gear  120  to rotate, which moves rack  26 , which moves moveable jaw  20 . Thus, the gear train  110  operatively couples shaft  80  to moveable jaw  20 .  
         [0025]     As noted above, worm gear  120  is mounted substantially inside head section  30  of wrench body  12 . In order to accommodate this, the head section  30  includes a corresponding worm mounting recess  40 . The worm mounting recess  40  may advantageously have a generally cylindrical cross section, centered on the worm gear rotational axis R. One end of the recess  40  narrows, such as via a suitable taper, to form hole  42  for accepting the seating portion  122  of worm gear  120 . The other end of recess  40  helps form opening  36 . An internal passage connects worm mounting recess  40  to handle recess  54 , with shaft bevel gear  150  disposed in this internal passage. Head section  30  also includes another recess, known as the rack mounting recess  46 , for accommodating rack  26  of moveable jaw  20 . The rack mounting recess  46  includes a forwardly open (i.e., opening generally in direction X) slot  48  for accommodating moveable jaw web  24 . Rack mounting recess  46  opens directly into worm mounting recess  40 , so that rack  26  may engage worm tooth  132 . Opening  36  is thus shaped somewhat like the numeral “ 8 ” with an upwardly extending center leg. See  FIG. 5 . The lower portion of opening  36  is centered about the worm gear&#39;s rotational axis R.  
         [0026]     In operation, the movement of jaw  20  is controlled by the rotation of worm gear  120 . However, unlike in conventional adjustable wrenches, the user does not directly turn the worm gear  120  to adjust the jaw spacing. Instead, the user adjusts the jaw spacing by moving actuator  72  along handle  50  in a sliding fashion. This movement causes the shaft  80  to rotate, with this rotational movement transferred to the worm gear  120  as described above.  
         [0027]     The marketplace expects adjustable wrenches to be robust. As such, many commercial adjustable wrench products are tested against the proof torque requirements of ASME B107.8 (2003). Some embodiments of the present invention incorporate various measures, which may found alone or in combination, in order to be more robust so as to pass the proof torque requirements of ASME B107.8. One approach taken is to strengthen the sidewalls  34   a , 34   b  proximate the worm mounting recess  40  so as to help keep the worm gear  120  in better contact with the moveable jaw&#39;s rack  26  during loading. To that end, the thickness T of the sidewalls  34   a , 34   b  is increased in some embodiments. That is, if recess  40  centered about the worm gear&#39;s rotational axis R is considered to be a cylindrical bore with diameter D, then the wall thickness T of the proximate sidewalls  34   a , 34   b  should each be about 1/4  D or more. This thickness is measured from the worm gear&#39;s rotational axis R radially outward in a direction Z that is both normal to the rotational axis R and generally perpendicular to direction X. This thickness T is believed to strengthen the sidewalls  34   a , 34   b  against a spreading deflection outward away from each other (up/down in the view of  FIG. 5 ), thereby maintaining the worm gear  120  and the moveable jaw&#39;s rack  26  in proper engagement.  
         [0028]     Another approach to making the wrench more robust, found in some embodiments, is used to help insure that the bevel gears  140 , 150  stay engaged. To this end, longitudinal shifting of the shaft  80  position is limited, or advantageously entirely prevented, by the interaction of retainer  66  against support flanges  60   a , 60   b . This movement restriction helps insure that shaft bevel gear  150  does not move away from worm bevel gear  140  under load, which may otherwise occur due to the slanted gear-to-gear interaction.  
         [0029]     The wrench  10  may be assembled in a variety of ways. In one embodiment, a forged wrench body  12  is provided that includes the handle  50 , the fixed jaw  32 , the sidewalls  34   a , 34   b , handle  50 , etc. In addition, shaft bevel gear  150  is attached to shaft  80 , such as by press fitting and/or pinning. The shaft  80  is then fed through support flanges  60   a , 60   b , through debris shield  100 , and into support  64 . During this process, the shaft  80  may need to be guided onto peg  76  of actuator  72 . Then, retainer  66  is inserted into gap  62  between support flanges  60   a , 60   b , and button  74  is affixed to peg  76 , thereby joining shaft  80  to cover plate  56 . Worm bevel gear  140  is joined to (e.g., press fit onto) securing section  126  of worm gear  120 . Optional bias spring  121  is placed around seating section  122 , rack  26  and worm gear  120  inter-engaged, and worm gear  120  inserted into worm mounting recess  40  and rack  26  inserted into rack mounting recess  46  with web  24  of moveable jaw  20  inserted into slot  48 . The retainer cap  129  is then loosely screwed into wrench body  12  to retain worm gear  120 . The shaft  80  assembly is then added, so that shaft bevel gear  150  engages worm bevel gear  140 , and cover plate  56  is secured to handle  50  via one or more suitable screws. Note that care should be taken to have the actuator  72  in an appropriate location along shaft  80  that corresponds to the location of the moveable jaw  20 . Indeed, in some advantageous embodiments, the full travel of the actuator  72  corresponds to the full travel of the moveable jaw  20 , and the components should be assembled accordingly. The retainer cap  129  is then tightened and secured in place, such as by staking or glue.  
         [0030]     The various components of the wrench may be made from any suitable materials known in the art, such as hardened steel, reinforced plastics, and the like. However, it may be advantageous for the shaft  80  and debris shield  100  to be made from brass or other materials that are easier to machine. The external portions of the wrench may be nickel chrome plated, or otherwise treated for a desirable appearance. The gears  140 , 150  may be metal injection molded (MIM&#39;d) if desired with a hardness of 35-40 Rockwell C. The worm gear  120  should be formed of a suitably hard material to withstand the interactions with the teeth  27  of rack  26  under load, such as by having a hardness of about 41-47 Rockwell C, with the teeth  27  having a hardness of about 43-47 Rockwell C. In addition, the support flanges  60   a , 60   b  and support  64  may be braised to cover plate  56  if desired.  
         [0031]     It should noted that the rack  26  of moveable jaw  20  may be shorter in length than in conventional adjustable wrenches so as to allow portions of the moveable jaw  20  to traverse beyond gear  140  for greater adjustability. Further, in some embodiments, the wrench  10  may optionally include one or more scales  34  that indicate the spacing between the jaws. A portion of such scale  34  can be on the main wrench body  12 , with an indicator  29  printed or etched on moveable jaw  20 . One scale  34  may be in “English” units on one face of the wrench  10  and another scale  34  may be in metric units on the opposing face of the wrench  10 . Also, in some embodiments, the spiral groove  92  on the shaft  80 , the bevel gears  140 , 150 , and the tooth  132  on worm gear  120  may, if desired, be sized such that the worm gear  120  and the shaft  80  rotate the same number of revolutions for a given amount of travel by moveable jaw  20 .  
         [0032]     While the discussion above has assumed that the support flanges  60   a , 60   b  and retainer  66  are disposed between the spiral groove  92  and the shaft bevel gear  150 , such is not absolutely necessary. In some embodiments, the support flanges  60   a , 60   b  and the retainer  66  may be disposed rearward of the spiral groove  92 , distal from the shaft bevel gear  150 . However, such arrangement is believed to be more susceptible to adverse manufacturing tolerances.  
         [0033]     The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.