Abstract:
A tool for adjusting extremely tight lug nuts, such as often found on tractor-trailer trucks, consists of a socket wrench pulled by a screw and anchored against another lug nut coaxial to the one being adjusted. A hand crank turns the screw, which in turn pulls the handle of the socket wrench toward the anchor yielding very high torque multiplication. The tool is elongated and shaped to permit its use in the tight space found in the annular recess surrounding the hubs of most truck wheels.

Description:
PRIORITY CLAIM 
     This nonprovisional application for patent claims priority of copending provisional application No. 60/244,873 filed Nov. 2, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     For safety reasons, it has been desirable to fasten truck wheel lug nuts with power tools (e.g., pneumatic drivers) that can deliver higher torques than have been obtainable by hand. As a result of this need for power assistance in tightening, a power driver is required any time a tire needs to be removed or the tightness of a nut needs to be checked or adjusted. This means that such work must be done in a service center, or, in the event of a roadside emergency, by either a roadside service vehicle or an on-board power driver if available. However, roadside service is expensive and time-consuming, and sufficiently powerful on-board equipment is expensive. A need exists for a lower cost alternative. 
     The lower cost alternatives are often manual tools. However, the use of manual tools on truck wheels is complicated by the fact that most truck wheels except those on the front end have lug nuts that are recessed as much as a foot from the outer edge of the tire. If a conventional wrench or breaker bar is used with an extension enabling access to these lugs, not only does the user have to support the weight of the wrench, he also has to balance his rotational force to keep from twisting the tool off the lug nut. The present invention anchors the tool and balances the forces so that only the modest weight of the tool need be supported manually. 
     SUMMARY OF THE INVENTION 
     The present invention is a tool for tightening or loosening a fastener, the tool being anchored against reactive force to a nearby fastener or stud, and utilizing a screw to pull or push a wrench handle against the anchor. The screw increases the hand torque applied to it to levels comparable to a power driver. Further, the tool is shaped to permit its use in the tight space found in the annular recess surrounding the hubs of most truck wheels. Principal objects of the invention are to provide: a) a hand tool capable of generating the very high torques needed to adjust truck wheel lug nuts with relatively low cost, weight, and space requirements; b) a tool that can be used on a variety of lug nut configurations including both recessed nuts (such as are typically found on rear axle wheels of tractor-trailer trucks) as well as easily-accessible nuts (such as those usually found on the front wheels of truck tractors); c) a tool designed so that the active and reactive forces are collinear and the moments coaxial so that the user does not have to resist applied forces during use of the tool to keep it in place; and d) a tool designed to keep internal stresses that would reduce efficiency due to friction to a low level. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a first embodiment of the tool contemplated by the present invention. 
     FIG. 2 is a perspective view of the wrench portion of the first embodiment. 
     FIG. 3 is a perspective view of the anchor portion of the first embodiment. 
     FIG. 4 is a perspective view of the first embodiment about to be applied to a work piece and an anchor piece on a typical truck wheel. 
     FIG. 5 is a view of the first embodiment from the viewpoint of a user when applied to a work piece and an anchor piece before the work piece is loosened. 
     FIG. 6 is a view of the first embodiment from the viewpoint of a user when applied to a work piece and an anchor piece after the work piece is loosened. 
     FIG. 7 is a perspective view of the first embodiment with an added torque indicator assembly. 
     FIG. 8 is a cutaway perspective view of the first embodiment with an added torque indicator assembly. 
     FIG. 9 is a close-up cutaway perspective view of the upper portion of the torque indicator assembly. 
     FIG. 10 is a perspective view from the left showing a simple configuration for engaging the two parts of the torque indicator assembly. 
     FIG. 11 is a perspective view of a second (preferred) embodiment of the tool contemplated by the present invention. 
     FIG. 12 is a perspective view of the wrench portion of the second embodiment. 
     FIG. 13 is a perspective view of the anchor portion of the second embodiment. 
     FIG. 14 is a perspective view of the second embodiment about to be applied to a work piece and an anchor piece on a typical truck wheel. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring again to the drawings, in which like details are referenced by like numerals, a detailed description of the invention is given below. 
     FIG. 1 is a perspective view of the first embodiment of the tool contemplated by the present invention. It is an extended socket wrench, the handle of which is pulled by the action of a screw against a similarly extended and coaxial anchoring device. It comprises a wrench portion  1  having a wrench arm  2 , said wrench portion cooperating slidably and coaxially with an anchor portion  3  having an anchor arm  4 . The wrench arm  2  and the anchor arm  4  are gripped and moved relative to one another by an actuator assembly  6  comprising talons  5   a  and  5   b , respectively, riding on a screw  7  that is threaded its entire length from point X to point Y. The distance between the talons is changed by rotating screw handle  8  in either direction. As oriented in FIG. 1 with threads being right handed, when the handle is rotated clockwise (toward the reader) the screw  7  pulls talon  5   b  towards talon  5   a , thereby rotating wrench portion  1  counterclockwise within anchor portion  3 . The anchor portion  3  cannot rotate clockwise in reaction to this pull because it is held in place by anchor socket  9 , and so wrench socket  10  must turn counterclockwise. A small force on handle  8  is multiplied by the leverage of the arms  2  and  4  and the incline of the threads of screw  7  into a large torque at wrench socket  10 . The entire actuator assembly  6  is removable from the rest of the tool. In this embodiment, the arms  2  and  4  are hollow and the talons  5   a  and  5   b  grip them by means of round teeth (not shown) inserted into the arms. The depicted means of attaching the actuator assembly  6  to the arms  2  and  4  is not intended to exclude other equally strong attachment means, such as, for example, replacing the talon teeth with drill holes capable of being slipped over the ends of the arms. 
     The arms  2  and  4  extend an equal distance from the common axis of portions  1  and  3 . This ensures that the radial components of the forces on the arms (away from the axis of the tool) which would tend to detach the talons from the arms, are negligible. Further, the arms are bent as shown so that they interfere minimally when the talons are drawn close together by the screw. The bends in the arms also cause the plane of motion of the screw and the talons to be always normal to the common axis of portions  1  and  3 , thereby ensuring that forces collinear with the tool axis (thrust forces) which would tend to disengage the tool from the work piece and/or anchor piece, are minimal. If the forces on the tool components were to be diagrammed with vectors, the diagram would show net zero resultants and moments at all points except for the weight of the tool itself. 
     FIG. 2 is a perspective view of the wrench portion  1  of the first embodiment. It comprises a hollow shaft  20  to which is welded a wrench arm  2  at one end and a square socket drive  21  at the other. Wrench arm  2  is angled downward and rearward slightly at  22 , then upward and forward slightly at  23 , to better cooperate with the anchor arm depicted in the following figure. A conventional wrench socket (not shown) is affixed to the drive  21  to grip a lug nut on a truck wheel (not shown). 
     FIG. 3 is a perspective view of the anchor portion  3  of the first embodiment. It comprises a hollow tube  30  of an inside diameter greater than the outer diameter of hollow shaft  20  in FIG.  2 . Anchor arm  4  is welded to the upper end  31  of tube  30 . Arm  4  is angled upward and forward slightly at  24 , then downward and rearward slightly at  25 , to better cooperate with the wrench arm depicted in the preceding figure, i.e., so that the ends of both arms  2  and  4  always lie in the same plane, a plane perpendicular to the axes of shaft  20  and tube  30 , and so that the two arm ends can meet each other closely regardless of which way they are rotated. The depicted configuration of bends is not meant to preclude more rounded or more sharply bent arm shapes that would accomplish the same purpose. 
     To the lower end  32  of the tube  30  is fixedly attached a slotted guide  33 . The purpose of the guide  33  is to provide an adjustable anchor point for the tool on an adjacent lug nut. The distance between lug nuts on truck wheels varies due to the size and type of hub and the number of lug nuts per wheel, so the anchor point is comprised of a lug nut socket (not shown) on the square end  39  of a movable boss  35  that rides in the slot  38  of the guide  33 . The guide  33  is curved in a plane normal to the axis of tube  30 , the curvature having a radius R matching that of the typical lug nut array (not shown) on a truck wheel (not shown). This is helpful in the event the lug nuts are recessed into a narrow annular space around the hub of the wheel, as they often are; the width of the guide  33  and its attached parts is narrow enough to fit into the annular space containing the lug nuts. A bolt  34  is screwed into a square boss  35  through washer  36 , guide  33  and washer  37  without compressing the washers against the guide, so that the boss  35  can ride slidably along the guide  33  and rotate freely on an axis parallel to the axis of tube  30 . Boss  35  has a square end  39  identical to socket drive  21  of FIG. 2, so that identical and interchangeable sockets can be used on both the anchor piece and the work piece. The guide  33  and the washers  36  and  37  are wide in a direction normal to the axis of tube  30  so that when the boss  35  is pushed sideways by reactive torque during operation of the tool, the axis of boss  35  is kept parallel to the tool axis, reducing any tendency of the tool to twist loose from either the work piece or the anchor piece during use. The square end of boss  35  accommodates a conventional wrench socket (not shown) identical to that applied to the wrench shaft  20  of FIG. 2 which grips the anchor piece, typically another lug nut (not shown) on the same truck wheel. 
     FIG. 4 is a perspective view of the wrench portion  1  and the anchor portion  3  of the first embodiment assembled together coaxially and ready for application to a work piece  40  and an anchor piece  41  on a typical truck wheel  42 . Assembly is accomplished by sliding the square drive end of portion  1  into the upper end  31  of portion  3  until the wrench arm  2  comes in contact with upper end  31 . When applied to a wheel, the direction of anchor arm  4  will be toward whichever lug nut or stud is to be used as the anchor piece  41  for the tool. The orientation of wrench arm  2  about the tool axis may be any one of N directions for an N-sided socket applied to a work piece consisting of an N-sided lug nut. (N is typically six.) Out of these N directions, the user must choose the direction that will put the ends of the arms as far apart as they can be yet still be gripped by talons  5   a  and  5   b  on actuator assembly  6  (FIG.  1 ). Screw  7  of FIG. 1 should be long enough to span the ends of the arms  2  and  4  when the initial angle Ai between them, in their plane of revolution, is as large as about 110 degrees. 
     FIG. 5 is a view of the first embodiment from the viewpoint of a user when applied to a work piece (hidden under socket  10 ) and an anchor piece (hidden under socket  9 ) on truck wheel  42  before the work piece is loosened. Actuator assembly  6  may be put in place by rotating talon  5   b  around the threads of screw  7  (or rotating screw  7  within talon  5   b ) until the distance between the talons is such that the talon teeth (not shown) can be inserted into the ends of arms  2  and  4 . Note the position of mark M on the side of wrench socket  10 , and the initial angle Ai between arms  2  and  4 . 
     FIG. 6 is a view of the first embodiment from the viewpoint of a user when applied to the same work piece and anchor piece after the work piece is loosened. Assuming right-handedness on all threads, handle  8  on actuator assembly  6  has been rotated in direction C (into the drawing) a number of times, drawing talon  5   b  closer to talon  5   a  and reducing angle Ai in FIG. 5 between arms  2  and  4  to angle Af This has caused shaft  20  to rotate counterclockwise within tube  30  a small amount, in turn forcing wrench socket  10  to rotate in a counterclockwise direction as well. This is clear from the fact that mark M on socket  50  in this figure has been displaced to the left of its position in FIG.  5 . Only a few degrees of motion should be necessary in most cases to loosen a work piece to a degree sufficient to enable complete removal by hand or conventional lug wrench after the talons  5  have been drawn fully together. In the event further loosening is required, it is necessary for the user to remove the actuator assembly  6  (to the right in this figure) from the arms  2  and  4 , re-orient the wrench portion  1  one “flat” clockwise on the work piece, wind talon  5   b  away from talon  5   a  on screw  7 , reapply the actuator assembly to the arms, and turn the handle in direction C again. 
     FIG. 7 is a perspective view of the first embodiment completely assembled as in FIG. 6, but with an added torque indicator assembly  74  comprising a rod  70 , a pointer  71 , a pivot  72  and a scale  73  attached to the shaft  20  and arm  2  of wrench portion  1 . 
     FIG. 8 is a cutaway perspective view of the first embodiment with the added mechanical torque indicator of FIG.  7 . The cutaway is necessary to show that the rod  70  extends all the way to the bottom end  78  of hollow shaft  20 . The lower end  75  of rod  70  is rigidly attached to the inside of the bottom end  78  of hollow shaft  20 . The upper end  76  of rod  70  curves over the top edge  77  of shaft  20  and flexibly engages pointer  71 , as is more clearly shown in FIGS. 9 and 10. Pivot  72  and scale  73  are fixedly attached to arm  2 . 
     FIG. 9 is a close-up cutaway perspective view of the upper portion of the mechanical torque indicator of FIG. 7, more clearly showing how pin  80  through pointer  71  rests slidably on pivot  72 . When wrench arm  2  is pulled toward the viewer in an attempt to loosen a lug nut engaged by drive  21  on the bottom of shaft  20  (not visible), the arm  2  will apply a counterclockwise torque on shaft  20  as indicated by arrow T. This torque will cause the top edge  77  of shaft  20 , as well as arm  2 , pivot  72 , and scale  73 , to be displaced in a counterclockwise direction relative to the bottom of the shaft (not shown) because of the elasticity of the material in the shaft. The curved upper end  76  of the indicator rod  70 , however, because it is rigidly attached to the bottom of the shaft, tends not to move with the upper end of shaft  20  and attached parts. The upper end  76  of rod  70  tends therefore to prevent the inner end  82  of pointer  71  from moving counterclockwise. Because the pivot  72  is also moving counterclockwise with arm  2 , it tends to rotate pointer  71  counterclockwise about pivot  72 , causing the tip  81  of the pointer  71  to move in a counterclockwise direction. Because pivot  72  is much closer to the upper edge  77  of the shaft  20  than the center  83  of the pointer  71 , The counterclockwise motion of pointer tip  81  is magnified relative to the counterclockwise rotation of arm  2  and scale  73 , so that tip  81  will move visibly over the scale  73  toward the viewer in this drawing. All of these displacements will be proportional to the applied torque, and as long as the elastic limit of the shaft material is not exceeded, they will also be reproducible. Therefore, indicia  84  may be placed on the scale  73  in units of torque to indicate replicable torque readings. Such readings may be of use in preventing the hazard of over- or under-tightening fasteners. 
     FIG. 10 is a close-up perspective view of the mechanical torque indicator from the left showing a simple means of flexibly engaging inner end  82  of pointer  71  with upper end  76  of rod  70 . A slot  90  formed into end  76  fits slidably over the upper comer  91  of inner end  82  so that rod  70  can push end  82  from side to side as torque in either direction is applied to the tool. This motion in turn causes a magnified and opposite side to side motion in the opposite end  81  of pointer  71 . 
     FIG. 11 is a perspective view of a second embodiment of the tool contemplated by the present invention. In the following figures, parts of the second embodiment corresponding to parts of the first embodiment are indicated by a prime (′) after the numeral. The second embodiment differs from the first in that: a) arm  2  of the preceding figures is replaced by driven gear  100  which is toothed around its entire periphery and is rigidly attached to the upper edge  77  of shaft  20  (now  77 ′ and  20 ′, respectively); b) arm  4  is shortened and comprises a worm gear bearing  101 . Bearing  101  comprises journals  102   a  and  102   b , which hold a worm gear  103  which is turned by, and is fixedly engaged to, a handle  104 . The worm gear  103 , handle  104 , and bearing  101  and journals  102  replace the screw  7 , handle  8  and talons  5  shown in FIG.  1 . If The worm gear  103  has right-handed threads, it will engage the teeth of driven gear  100  such that when handle  104  is turned in direction D, the driven gear will turn in direction E, rotating shaft  20 ′, socket  10 ′, and a work piece (not shown) in the same direction. By suitably sizing the gears, arms and handle, sufficiently high mechanical advantage can be achieved to loosen the tightest fasteners with moderate manual pressure. 
     FIG. 12 is a perspective view of the wrench portion  1 ′ of the second embodiment, comprising shaft  20 ′, square drive  21 ′, and driven gear  100 . 
     FIG. 13 is a perspective view of the anchor portion  3 ′ of the second embodiment, comprising tube  30 ′, a shortened anchor arm  4 ′, and worm gear bearing  101  welded to arm  4 ′. The remaining parts of the anchor portion of the second embodiment are the same as those of the first embodiment. 
     FIG. 14 is a perspective view of the wrench portion  1 ′ and the anchor portion  3 ′ of the second embodiment assembled together coaxially and ready for application to a work piece  40  and an anchor piece  41  on a typical truck wheel. Assembly and positioning are accomplished first by sliding the square drive end of the wrench portion  1 ′ into the upper end  31 ′ of anchor portion  3 ′, and attaching wrench socket  10 ′ and anchor socket  9 ′ to the square drive (hidden) and anchor boss (hidden) respectively; second, by placing the anchor socket  9 ′ over anchor piece  41 ′ on a wheel next to whichever work piece  40 ′ it is desired to loosen; and third, by placing the wrench socket  10 ′ over the selected work piece  40 ′. It may be necessary to turn the driven gear  100  by hand prior to meshing the driven gear  100  and the worm gear  103 , or by meshing these gears and then turning handle  104  in either direction, to cause the wrench socket  10 ′ to fit over the work piece  40 ′. The work piece  40 ′ can then be loosened or removed completely, without removing the tool from the wheel, by turning handle  104  as many revolutions as required. 
     Although not specifically illustrated, the torque indicator portion of the first embodiment may also be incorporated readily into the second embodiment by affixing the pivot  72  and the scale  73  of FIG. 7 to the upper surface of the driven gear  100  of FIG. 11, the rest of the assembly being identical to that shown in FIG.  8 . Further, it is noted that similar mechanical torque indicating devices may be attached alternatively to anchor portion  3 . Still further it is noted that in either of the embodiments, an electronic strain gauge may be attached to any one of various stressed parts of this tool, instead of mechanical indicator parts, such that an analog or digital readout of torque could be displayed at a convenient spot on the tool. For example, a strain bridge could be attached to the inner.wall of wrench shaft  20  or  20 ′, energized by a small battery and readable by a potentiometer installed in the shaft and displayed on an LCD mounted on top of the shaft. 
     In light of the drawing descriptions, the differences between these two embodiments can be summarized by saying that the first embodiment may be less expensive than the second to fabricate, because it does not comprise gears and does not require the small manufacturing and assembly tolerances necessary for smooth and efficient meshing of the gears. The advantage of the second embodiment is one of convenience, in that the loosening process can be extended to the point of complete removal of the fastener, if desired, without repositioning parts of the tool. 
     This invention contemplates a third embodiment, not illustrated, in which a pipe wrench is employed in place of wrench arm  2  in the first embodiment. The jaws of the pipe wrench are placed around that section of shaft  20  protruding above tube  30  so that they grip the shaft when the handle of the pipe wrench is pulled in the fastener-loosening direction. A screw-operated actuator assembly capable of gripping the handle of the pipe wrench and the end of anchor arm  4  similar to assembly  6  shown in the illustrations of the first embodiment is used to pull the handle of the pipe wrench toward anchor arm  4 . A common c-clamp or bar clamp with its ends adapted to hold securely the handle of the pipe wrench and the end of anchor arm  4  serves the purpose of an actuator for this third embodiment of the tool. The advantage to this embodiment over the first two might be cost if a suitable pipe wrench and clamp are available.