Abstract:
The present invention relates to the field of open-ended wrenches, and more specifically to a dual pawl assembly which can be used within an open-ended ratchet wrench to facilitate a bi-directional ratcheting motion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 12/419,791 filed on Apr. 7, 2009. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates to the field of open-ended wrenches, and more specifically an open-ended ratchet wrench with a dual pawl assembly which facilitates bi-directional ratcheting motion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  illustrates an isometric view of an exemplary embodiment of an open-ended ratchet wrench. 
           [0004]      FIG. 2  illustrates an exploded view of an exemplary embodiment of open-ended ratchet components and a ratchet wrench housing with a cavity for ratchet wrench components. 
           [0005]      FIG. 3  illustrates a perspective view of an exemplary embodiment of a open-ended ratchet wrench housing with a cavity for ratchet wrench components 
           [0006]      FIG. 4  illustrates an exploded view of an exemplary embodiment of open-ended ratchet wrench components. 
           [0007]      FIG. 5  illustrates an isolated view of an exemplary embodiment of a pair of v-pawls. 
           [0008]      FIG. 6  illustrates a top view of an exemplary embodiment of an open-ended ratchet wrench assembly. 
       
    
    
     GLOSSARY 
       [0009]    As used herein, the term “alternately engage” means to engage at alternate positions during a series of rotational movements in either direction. 
         [0010]    As used herein, the term “change detent” means a component with grooves or notches that is used to mechanically resist and enable rotation. 
         [0011]    As used herein, the term “coil spring” means any spring of wire coiled helically, having a cylindrical or conical outline. 
         [0012]    As used herein, the term “flex spring band” means any flexible piece of material which exerts a force at either end when pressure from other components is used to bend it, forcing the ends in opposite direction. A flex spring band may include a leaf spring, piece of sheet metal, piece of plastic, or a wire, 
         [0013]    As used herein, the term “portion” means a subset or part of a whole which is less than all. 
         [0014]    As used herein, the term “protuberance” means any bulge, knob, projection, or swelling, which protrudes. 
         [0015]    As used herein, the term “ratcheted crescent” means a c-shaped component with an outer rim having a plurality of ratchet teeth attached. 
         [0016]    As used herein, the term “ratchet engaging teeth” means a structural component of a pawl, which may be of varying sizes and configurations, used to engage the teeth of a ratchet. 
         [0017]    As used herein, the term “v-pawl” means a pawl, or movable component which has two lever arms in the shape of a “V,” which operates as a lever and which includes teeth which engage a ratchet. 
         [0018]    As used herein, the term “v-pawl lever arm” means an elongated section protruding from a v-pawl. 
       BACKGROUND 
       [0019]    A ratchet wrench is a type of wrench having ends that surround the nut or head of a bolt. The wrench provides a mechanical advantage by applying torque to turn bolts, nuts or other items designed to interface with a wrench. The ratcheting mechanism allows the nut or bolt to be tightened or loosened with a reciprocating motion of the wrench, without requiring that the wrench be removed, refitted, and repositioned after each turn. 
         [0020]    A ratchet wrench includes ratchet and pawl components known in the mechanical arts to control and secure movement. Ratchets consist of a ratchet wheel, and may include a spring assembly which applies pressure to a pivoting spring loaded finger called a pawl that engages the teeth. Either the teeth, or the pawl, are slanted at an angle, so that when the teeth are moving in one direction, the pawl slides up and over each tooth in turn, with the spring forcing it back with a ‘click’ into the depression before the next tooth. When the teeth are moving in the other direction, the angle of the pawl causes it to catch against a tooth and stop further motion in that direction. 
         [0021]    More specifically, a pawl is a movable component which operates as a lever and which includes protuberances which engage a ratchet. The pawl is used to control the direction of the ratchet. In various embodiments, bolt engaging components may be used to apply pressure to a pawl (e.g., a spring loaded component) to keep a pawl engaged within the teeth of a ratchet. A pawl may be machined, stamped or molded and constructed of one or more components having singular or multiple protuberances. 
         [0022]    Generally, a ratchet wheel is similar to other types of gear wheels, except that its teeth or cogs may be cut with a sloped side and a “straight” or “offcut” side. That is in contrast to the two sloped sides of the tooth or cog on a regular gear wheel. Additionally, there is usually a curve in the slope of the “regular” side that acts as a ramp for the pawl to ride on. The pawl, which is usually spring loaded to keep it engaged with the teeth, will, when the ratchet wheel is rotated in one direction, slide up or “climb” the slanted or sloped side of a tooth. The pawl will then “jump” down into the bottom of the tooth space after going over the tip of the tooth, and the spring will have pushed it there. It will then ride up the next slope on the next tooth as the ratchet wheel moves in the same “forward” direction. But if the ratchet wheel is rotated in a “backward” direction, the pawl will only allow movement until it comes in contact with the “straight” side of the next tooth back and it will jam there. This will limit backward movement of the ratchet wheel to a tooth length and no more, as long as the pawl is acting normally to check the backward rotation. 
         [0023]    Reversible ratchet wrenches are also known in the art. A reversible ratchet wrench has a handle portion and a head portion. Key features of a reversible ratchet wrench include one or two pawls having teeth which alternately engage the teeth on a ratchet wheel. In the case of two pawls, both pawls typically share a common pivot point. A lever determines the direction in which torque force is applied by engaging one pawl or the other. As seen in ratchet wrenches known in the art, one of the two pawls will engage the ratchet while the other pawl does not. One pawl will contain protuberances or teeth adapted to allow the ratchet to apply torque in one direction while the other pawl contains protuberance or teeth in an opposite configuration to allow the ratchet to apply torque in the other direction. Likewise, when a single pawl assembly is used, only one side of the pawl is engaged at a time. The torque force of the ratchet is alternately applied, the pressure released, and the ratchet wrench repositioned for the next application of torque force. 
         [0024]    One problem generally known in the art with box type wrenches using ratchet and pawl systems is that the head of the wrench is generally closed, and threaded components (such as brake lines) will not allow the wrench to fit over them. 
         [0025]    Various attempts are known in the art to create an open-ended ratchet wrench. However, these wrenches require a large rotational degree in order to use the wrench which is not possible in confined spaces. The need for a large rotational movement lessens the utility of these wrenches. If a large degree of motion is required to rotate the ratchet, the wrench cannot be used in smaller spaces. Attempts are also known in the art to create more efficient ratcheting mechanisms. 
         [0026]    A need exists for an open-ended ratchet wrench assembly that can rotate a ratchet within small degrees, known as ratcheting arc to a person of ordinary skill in the art. 
         [0027]    It is desirable to introduce an open-ended box wrench using a ratchet and dual pawl system which can operate at small rotational degrees (ratcheting arc) and which can be affordably manufactured and mass produced, and which does not require specialized parts or multi-component pawl assemblies. 
       SUMMARY OF THE INVENTION 
       [0028]    The present invention is a reversible open-ended ratchet wrench which utilizes a dual v-pawl ratchet assembly comprised of an open-ended wrench housing having a cavity to enclose critical ratchet assembly. 
         [0029]    In various embodiments the ratchet assembly components may include a ratcheted crescent with an outer ratchet edge including a plurality of ratchet teeth. The cavity further includes at least two pivotal v-pawl components. 
         [0030]    Each of the v-pawl components is comprised of two angled v-pawl lever arms positioned at a critical angle of 90 to 150 degrees relative to each other. The v-pawl lever arms have an outer end from which a plurality of ratchet engaging teeth are formed. The ratchet engaging teeth of each of the v-pawl lever arms alternately engage a portion of the ratchet teeth all times. 
         [0031]    In various embodiments a multi-position change detent can be used to exert a variable force on said flex spring band when actuated by a thumb lever. The flex spring band is connected to each of the v-pawls and will cause them to pivot and engage the ratchet. Finally, the reversible ratcheted wrench includes a cover plate which separates the thumb lever and the multi-position change detent. 
         [0032]    This configuration allows smaller for a reduced ratcheting arc of 50 percent and therefore a smaller wrench rotation of down to 2.5 degrees required to apply torque. The present invention further allows for a larger opening on the ratcheted crescent wheel because of the dual v-pawl assembly. The dual v-pawl assembly is advantageous because one pawl will always be in contact with the ratcheted crescent, even if one v-pawl passes over the open end of the ratcheted crescent. 
       DETAILED DESCRIPTION OF INVENTION 
       [0033]    For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of a simplified open-ended ratchet wrench with dual v-pawl assembly only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent simplified open-ended ratchet wrenches with dual pawl assembly may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. 
         [0034]    It should be understood that the drawings are not necessarily to scale; instead, emphasis has been placed upon illustrating the principles of the invention. In addition, in the embodiments depicted herein, like reference numerals in the various drawings refer to identical or near identical structural elements. 
         [0035]    Moreover, the terms “substantially” or “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. For example, a simplified open-ended ratchet wrench with dual pawl assembly may use two identical pawl mechanisms or may use two varied pawl components to engage opposite sides of the ratchet component. 
         [0036]      FIG. 1  illustrates an isometric view of an exemplary embodiment of reversible open-ended ratchet wrench. Open-ended ratchet wrench  100  may be used to apply torque force in a clockwise or counter-clockwise direction and may also be placed in a neutral position where ratcheted crescent  70  can spin freely within open-ended wrench head  20   a.    
         [0037]    In the embodiment shown, open-ended ratchet wrench  100  includes an ergonomic handle and a standard open-ended box wrench. As seen in the embodiment of  FIG. 1 , open-ended ratchet wrench  100  has ratchet wrench housing  10 , open-ended wrench heads  20   a  and  20   b  with head openings  24   a  and  24   b . Also shown in the embodiment is partially exposed ratcheted crescent  70 . Ratcheted crescent  70  is housed within open-ended wrench head  20   a.    
         [0038]    In the embodiment shown, open-ended wrench head  20   a  includes crescent shaped cover plate  80 , corresponding to the shape of ratcheted crescent  70 . Crescent shaped cover plate  80  is attached to the top of open-ended wrench head  20   a  and covers the top side of ratcheted crescent  70  and the inner assembly of ratchet wrench components (not shown in this figure). In the embodiment shown, crescent shaped cover plate  80  is attached to open-ended ratchet head  20   a  with cover plate screws  82   a  and  82   b . In other embodiments, crescent shaped cover plate  80  may be attached using other attachment means known in the art such as welding, rivoting, adhesive, machining, intregally molding; soldering, or any other means known to one of ordinary skill in the art. 
         [0039]    In the embodiment shown, open-ended ratchet wrench  100  includes thumb lever  81  which is located on top of crescent shaped cover plate  80 , but thumb lever  81  may be located in other positions closer or further to open-ended wrench head  20   a . In the embodiment shown, thumb lever  81  is a tear-drop shaped component with both a rounded and enlongated portion and attached by screws  83   a  and  83   b . As shown in the embodiment, thumb lever  81  pivots around its rounded upper portion and is used to change the direction and amount of torque or rotational resistance applied to ratcheted crescent  70 . Thumb lever  81  is used to actuate two internal v-pawls and a crescent-shaped ratchet component shown in subsequent drawings. 
         [0040]      FIG. 2  is an exploded view of an exemplary embodiment of open-ended ratchet components and ratchet wrench housing  10  with a cavity  22  for ratchet wrench components. In the embodiment shown, open-ended ratchet wrench components consist of ratcheted crescent  70 , v-pawls  90   a  and  90   b , leaf spring  71 , hinge pins  75   a  and  75   b , change detent  73 , ball bearing  72 , and coil spring  74 . In the embodiment shown, crescent shape cover plate  80  contains the ratchet wrench components within cavity  22 . 
         [0041]      FIG. 3  illustrates a perspective view of exemplary embodiment of ratchet wrench housing  10  which includes cavity  22  for ratchet wrench components (shown in  FIG. 2 ). Cavity  22  is critically contoured to receive and secure various ratchet wrench components. The critical contoured features of cavity  22  includes rounded inner surface  11  and a series of three indentations  12   a ,  12   b  and  13  at the end of rounded inner surface  11  which is most proximate to the wrench handle. V-pawl indentations  12   a  and  12   b  are symmetrical and accommodate v-pawls  90   a  and  90   b  (shown in  FIG. 2 ). Change detent indentation  13  is a larger semi-circular contour to accommodate the upper rounded portion of changed detent  73  (shown in  FIG. 2 ). Change detent indentation  13  further includes ball bearing aperture  76 . Cavity  22  is also defined by bottom surface  16  which further includes change detent aperture  77  and hinge pin apertures  14   a  and  14   b.    
         [0042]    As shown in the embodiment, cavity  22  is surrounded by securing rim  87  which is protrusion or edge that spans the outer rim of open-ended wrench head  20   a . Apertures  15   a  and  15   b  receive plate screws  82   a  and  82   b  to fixedly attach crescent shaped cover plate  80  to ratchet wrench housing  10 . 
         [0043]      FIG. 4  is an exploded view of an exemplary embodiment of open-ended ratchet wrench components. As shown in the embodiment, v-pawls  90   a  and  90   b  are curved components with v-pawl lever arms  94   a ,  94   b ,  94   c , and  94   d  in the shape of a “V.” In other embodiments, v-pawls may have more than two v-pawl lever arms each. In the embodiment shown, v-pawls  90   a  and  90   b  are positioned so that v-pawl lever arms  94   a ,  94   b ,  94   c , and  94   d  may engage ratchet teeth  78  on ratcheted crescent  70 . V-pawls  90   a  and  90   b  also include v-pawl slits  91   a  and  91   b . Further, in the embodiment shown, v-pawls  90   a  and  90   b  include v-pawl apertures  97   a  and  97   b  which receive hinge pins  75   a  and  75 . Hinge pins  75   a  and  75   b  are pivoting components which allow v-pawls  90   a  and  90   b  to pivot around hinge pins  75   a  and  75   b  at a rotation of 1 to 90 degrees. In other embodiments, hinge pins  75   a  and  75   b  may be other devices known in the art to allow v-pawls  90   a  and  90   b  to pivot or rotate around apertures  97   a  and  97   b . Hinge pins  75   a  and  75   b  engage hinge pin aperatures  14   a  and  14   b  (shown in  FIG. 3 ) and v-pawl apertures  97   a  and  97   b , thus allowing v-pawls  90   a  and  90   b  to pivot. 
         [0044]    As shown in the embodiment, ratcheted crescent  70  is an open-ended ratchet wheel in the shape of a crescent located within cavity  22 . Ratcheted crescent  70  has a pluarlity of proturbences or ratchet teeth  78  on its outer ratchet edge. Various embodiments of ratcheted crescent  70  may include more, fewer or differently proportioned ratchet teeth. In the embodiment shown, the inside of ratcheted crescent  70  is designed to match or correspond to a standard standard six-sided or hexagonal shaped nut, bolt head, or other hardware. In other embodiments, the inside of ratcheted crescent  70  may be designed to accommodate or engage other shaped mechanical pieces or hardware. 
         [0045]    In the embodiment shown, change detent  73  has three grooves  61   a ,  61   b , and  61   c  on its base side which are in contact with ball bearing  72 . Ball bearing  72  is held in contact with change detent  73  by coil spring  74 . Ratchet wrench housing  10  includes coil spring aperture  76  (shown in  FIG. 3 ) which is located within change detent indentation  13 . Coil spring  74  is located inside of coil spring aperture  76  (shown in  FIG. 3 ) along with ball bearing  72 . Coil spring  74  forces ball bearing  72  to engage or contact the grooves  61   a ,  61   b , and  61   c  of change detent  73 . 
         [0046]    As shown in the embodiment, change detent  73  also has change detent slit  79 . One end of leaf spring  71  is wedged into v-pawl slit  91   a  on v-pawl  90   a  while the other end is wedged into v-pawl slit  91   b  on v-pawl  90   b . The middle of leaf spring  71  is wedged into change detent slit  79 . 
         [0047]    As shown in the embodiment, thumb lever  81  is located on top of crescent shape cover plate  80  and is attached to change detent  73  by screws  83   a  and  83   b  into change detent apertures  86   a  and  86   b . Screws  83   a  and  83   b  go through hole  85  in crescent shaped cover plate  80 . In other embodiments, thumb lever  81  may be attached to change detent  73  with only one screw or by other attachment devices known to one of ordinary skill in the art. 
         [0048]      FIG. 5  illustrates an isolated close up view of an exemplary embodiment of v-pawls  90   a  and  90   b . In the embodiment shown, v-pawls  90   a  and  90   b  have two v-pawl lever arms each,  94   a ,  94   b ;  94   c , and  94   d . In other embodiments, v-pawl components  90   a  and  90   b  may have fewer or more v-pawl lever arms. In the embodiment shown, v-pawls  90   a  and  90   b  also include ratchet engaging teeth  93   a ,  93   b ,  93   c , and  93   d  at the end of v-pawl lever arms  94   a ,  94   b ,  94   c , and  94   d . In other embodiments, ratchet engaging teeth may vary in size, shape and length designed to interact with ratchet teeth  78  (shown in  FIG. 4 ). 
         [0049]      FIG. 6  is a top view of an exemplary embodiment of open-ended wrench head  20   a  withoutout cover plate  80  and thumb lever  81 . In the embodiment shown, cavity  22  contains ratcheted crescent  70 , v-pawls  90   a  and  90   b , leaf spring  71 , hinge pins  75   a  and  75   b , change detent  73 , ball bearing  72 , and coil spring  74  (not shown). Cavity  22  consists of rounded inner surface  11  adapted to accommodate the shape of ratcheted crescent  70 . Further, v-pawl indentation  12   a  and  12   b  are contoured accordingly to accommodate the shape of v-pawls  90   a  and  90   b  while change detent indentation  13  is contoured to accommodate the shape of change detent  73 . 
         [0050]    As seen in the embodiment of  FIG. 6 , leaf spring  71  is located between v-pawls  90   a  and  90   b . Leaf spring  71  is a flex spring band adapted to rotate or pivot v-pawls  90   a  and  90   b  when force is applied. In the embodiment shown, the ends of leaf spring  71  are wedged in the v-pawl slits  91   a  and  91   b  of v-pawls  90   a  and  90   b . In other embodiments, the ends of leaf spring  71  may be fixedly attached to v-pawls  90   a  and  90   b  by welding, adhesives, or any other attachment means known to one of ordinary skill in the art. Also, in other embodiments, leaf spring  71  may also be other types of flex spring bands affixed to change detent  73  and v-pawls  90   a  and  90   b  adapted to rotate v-pawls when the change detent is rotated. 
         [0051]    As seen in the exemplary embodiment, leaf spring  71  is attached in its middle to change detent  73 . In the embodiment shown, change detent  73  is a triangular shaped component which has three grooves  61   a ,  61   b , and  61   c  on its base side corresponding to multiple positions. Change detent  73  has change detent slit  79  where it is attached to leaf spring  71 . The bottom of change detent  73  has a small proturbance which fits into to the change detent aperture  77  (seen in  FIG. 3 ). The small proturbance on the bottom of change detent  73  allows change detent  73  to pivot about change detent aperture  77 . In other embodiments change detent  73  may be other shapes which have grooves or notches. Change detent  73  also includes change detent apertures  84   a  and  84   b  where thumb lever screws  83   a  and  83   b  attach change detent  73  to thumb lever  81  (shown in  FIG. 2 ). 
         [0052]    As shown in the embodiment, if change detent  73  is pivoted counter-clockwise, leaf spring  71  will bend and slightly pivot v-pawls  90   a  and  90   b  in a clockwise direction and the ends v-pawl lever arms  94   b  and  94   d  will engage with ratcheted crescent  70 . The angle of v-pawl lever arms  94   b  and  94   d  will allow ratchet teeth  78  to slide over ratchet engaging teeth  93   b  and  93   d  when ratcheted crescent is rotating in a clockwise direction. However, if ratcheted crescent  70  rotates in a counter-clockwise direction, ratchet engaging teeth  93   b  and  93   d  will catch and v-pawls  90   a  and  90   b  will lock in place, and the user may then apply torque to ratcheted crescent  70 . The opposite is also true if change detent  73  slightly rotates in the clockwise position; ratcheted crescent  70  will be able to rotate counter-clockwise but not clockwise. If change detent  73  remains in the neutral or middle position, no v-pawl lever arms will be engaged and ratcheted crescent can freely rotate in either direction. 
         [0053]    This embodiment allows for a smaller ratcheting arc and therefore a smaller wrench rotation of down to 2.5 degrees, or less depending on the number of ratchet teeth. In the exemplary embodiment shown, ratcheting arc is calculated using the equation: 
         [0000]    
       
         
           
             
               Ratcheting 
                
               
                   
               
                
               
                 Arc 
                  
                 ° 
               
             
             = 
             
               
                 
                   360 
                    
                   ° 
                 
                 
                   Number 
                    
                   
                       
                   
                    
                   of 
                    
                   
                       
                   
                    
                   Teeth 
                    
                   
                       
                   
                    
                   on 
                    
                   
                       
                   
                    
                   Ratchet 
                 
               
               × 
               
                 1 
                 2 
               
             
           
         
       
     
         [0054]    As seen in the embodiment, change detent  73  has three positions caused by the contact between ball bearing  72  and grooves  61   a ,  61   b , and  61   c  on change detent  73 ; these positions represent neutral, clockwise torque, or counter-clockwise torque. In other embodiments, change detent  73  may have a plurality or multiple grooves or positions which may be used to apply variable rotational resistance to ratcheted crescent  70 . Change detent  73  is held in place and restricted from rotating because of the pressure exerted by ball bear bearing  72  in grooves  63   a ,  63   b , or  63   c  and the frictional resistance between change detent  73  and crescent shaped cover plate  80 . Change detent  73  will not rotate until a user rotates thumb lever  81  (shown in  FIG. 2 ). When a user rotates thumb lever  81 , change detent  73  shifts into a new position, thus moving ball bearing  72  into another groove and locking it in position. Depending on the position of thumb lever  81 , change detent  73  will apply varying degrees of pressure to leaf spring  71  in different directions; leaf spring  71  will force v-pawls  90   a  and  90   b  to pivot and engage ratcheted crescent  70 .