Abstract:
A folding knife, comprising a blade pivotally connected to an elongate handle defining a recessed blade cavity and a blade opening assembly constructed and arranged to assist movement of the blade to an open position, in which the blade is extended. The blade opening assembly comprises, in one example, a bias element and an actuating member. The bias element is housed within the recessed blade cavity and has a free end. The actuating member is pivotally connected to the handle within the recessed blade cavity and is constructed and arranged to engage a portion of the tang of the blade and a portion of the bias element such that the blade may be assisted to the open position. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 C.F.R. § 1.72(b).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to folding tools, such as folding knifes, and more particularly to a mechanism for assisting the opening of a folding knife.  
           [0003]    2. Background Art  
           [0004]    Many types of folding tools are known. One well-known folding tool is the folding knife. One major concern of the user of a folding knife is the requirement of safely opening the knife to an open operative position. In the folding knife industry, there typically is provided a housing or handle for supporting the knife blade in the open position and for receiving the knife blade in the closed position. It is also known to cause the extended knife blade to be locked when in the open extended position. The present invention overcomes the deficiencies of folding knifes and opening mechanisms in the art by providing positive opening assistance to the user.  
           [0005]    The present invention allows for the opening of the folding knife with only a single hand of the user, to the advantage of the general public. Further, because, in the present invention, the knife blade of the folding knife must typically be manually moved a certain distance, whereupon the mechanism of the folding knife serves to urge the blade into the open position without the application of further outside force by the user, the folding knife of the present invention may not be considered a switch blade, and hence, is legal in most jurisdictions of the United States.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention relates to folding tools such as, for example, a folding knife. In one example, the folding knife has a blade, an elongate handle, and a bias element. The blade has tang at one end and has a cutting edge that extends along at least a portion of at least one side of the blade. The handle has a front end and a spaced back end. The handle also defines a recessed blade cavity therein. A pivot pin is provided for pivotally connecting the tang of the blade to the handle. In one example, the blade is pivotally connected to the handle proximate the front end of the handle so that the blade is rotatable about a rotational axis between an open position, in which the blade is extended, and a closed position, in which at least a portion of the cutting edge of the blade is disposed within the recessed blade cavity of the handle.  
           [0007]    The blade opening assembly comprises a bias element and an actuating member. The bias element has a proximal end that is connected to a portion of the handle and a free end spaced from the proximal end. The bias element is housed within the recessed blade cavity of the handle. In one embodiment, the bias element lies substantially in a plane defined by the blade of the folding knife.  
           [0008]    The actuating member is pivotally connected to the handle intermediate the tang of the blade and the bias element. Similar to the bias element, the actuating member is housed within the recessed blade cavity. In one embodiment, the actuating member may lie substantially in the plane defined by the blade. The actuating member has a peripheral edge surface defining a first arm and a second arm. In operation, a portion of the free end of the bias element engages the edge surface of the first arm of the actuating member and the second arm of the actuating member engages the tang of the blade such that the blade opening assembly assists movement of the knife blade to its open position.  
           [0009]    In one example, the tang of the blade has an edge that defines a shoulder therein. At least a portion of the shoulder defines a drive surface. In use, the actuating member is movable between a first position, in which the blade is in its closed position, and a second position, in which a portion of the second arm of the actuating member contacts a portion of the drive surface of the shoulder to create a toggle point such that the blade is selectively locked in its open position. Further, the blade opening assembly exerts an opening force to urge the blade into the open position when the user manually moves the blade from its closed position to beyond an equilibrium position. 
       
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a partial cut-away side view of a folding knife in the closed position showing the construction and arrangement of a bias element and an actuating member housed within a recessed blade cavity of a handle when in its closed position.  
         [0011]    [0011]FIG. 2 is a partial cut-away side view of the folding knife of FIG. I with a knife blade being manually moved toward its open position.  
         [0012]    [0012]FIG. 3 is a partial cut-away side view of the folding knife of FIG. 1 with a knife blade being urged toward its open position by a blade opening assembly.  
         [0013]    [0013]FIG. 4 is a partial cut-away side view of the folding knife of FIG. 1 with a knife blade in its open extended position showing the knife blade being selectively locked in its open position.  
         [0014]    [0014]FIG. 5 is a top plan view of the folding knife in its open position.  
         [0015]    [0015]FIG. 6 is an exploded perspective view of the folding knife.  
         [0016]    [0016]FIG. 7 is an expanded partial cut-away side view of the folding knife of FIG. 4.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Thus, the embodiments of this invention described and illustrated herein are not intended to be exhaustive or to limit the invention to the precise form disclosed. They are chosen to describe or to best explain the principles of the invention and its application and practical use to thereby enable others skilled in the art to best utilize the invention. As used in the specification and in the claims, “a,” “an,” and “the” can mean one or more, depending upon the context in which it is used. The preferred embodiment is now described with reference to the figures, in which like numbers indicate like parts throughout the figures.  
         [0018]    The invention relates to folding tools having a handle and a working portion in which at least a portion of the working portion is foldable within a portion of the handle when the tool is not in use. Accordingly, the term “folding knife” as used herein should also be understood to include other types of folding implements such as files, hand saws, and the like. Furthermore, those skilled in the art will appreciate that the device described herein, and its principles of operation and implementation, is broadly applicable to a wide variety of foldable implements generally and may be adapted to tools rather than knifes. Thus, while the present invention is hereinafter described with particular reference to a folding knife, the skilled artisan will note its many other applications.  
         [0019]    Referring to the figures, a folding knife  10  is generally composed of a handle or casing, a blade opening assembly held within the handle or casing, and a blade  30 . The handle has a front end  22  and a spaced back end  24 .  
         [0020]    In one embodiment, the handle has a pair of spaced opposing side members  40 , each with a front end  42  and a back end  44 . Each side member may also have an interior lining  46  positioned on at least a portion of the interior side of the side member. The side members  40  and, if used, the interior linings  46 , define a recessed blade cavity  26  within the handle  20 . The blade cavity is shaped so that at least a portion of the blade  30  may be disposed within the blade cavity when the blade is placed into a closed position. Each side member  40  has a plurality of openings  45  that receive conventional fasteners  60 , such as for example, threaded screws, bolts, nuts, and the like, to secure the side members  40  in spaced relation to each other. The interior lining, if used, may have a plurality of holes  47 .  
         [0021]    The blade  30  has a cutting edge  31  along at least a portion of one side thereof and a tang  32  at one end. In one embodiment, the tang of the blade has a peripheral edge  33  that defines a shoulder  34  and a stop  36  therein. The shoulder is spaced from the stop. At least a portion of the shoulder  34  of the tang defines a drive surface  35 .  
         [0022]    The blade is rotatably mounted to the handle about a rotational axis. In one example, the blade is mounted on a pivot pin  28  extending between the side members  40  of the handle proximate the front end  22  of the handle. The tang defines a bore  37  constructed and arranged to receive the pivot pin  28 . In one example, the pivot pin may be a conventional fastener. In operation, the blade is rotatable between the closed position, in which at least a portion of the cutting edge  31  is disposed within the blade cavity, and an open position, in which the blade is in an operative extended position.  
         [0023]    The folding knife may also include a spacer member  70  constructed and arranged for disposition between the side members  40 . In one example, the spacer member is connected to the handle proximate the back end of the blade cavity. The spacer member defines a slot  72  that extends generally toward the front end  22  of the handle when the spacer member is connected to the handle. The spacer member may also define an elongate portion  76  that extends generally toward the front end and at least partially along the upper edge of the handle when the spacer member is connected to the handle. The spacer member may be secured to the side members by conventional fasteners, adhesives, and the like. If conventional fasteners are used, the spacer member may have at least one bore  74  extending therethrough for operative receipt of at least a portion of the conventional fastener.  
         [0024]    In addition, one of the side members may have at least one male projection  48  extending substantially normal to interior side of the side member and the other side member may have at least one female depression  49  constructed and arranged for receipt of the ends of the male projection. One of the male projections  48  proximate the front end of the handle may form a stop pin  50 . The stop pin, by extending across the front end of the blade cavity, communicates with the stop  36  of the tang of the handle when the blade is positioned in the open, extended, position. In one example, at least one conventional fastener  60  is received within at least one of the holes  47  in the interior lining  46  and at least one male projection  48  is received within at least one of the holes of the interior lining. One will appreciate that each male projection  48  may be formed by a conventional fastener  60  that extends from one side member  40  to the other side member  40 .  
         [0025]    The folding knife of the present invention houses a blade opening assembly  80  within the blade cavity  26 . The blade opening assembly comprises a bias element  90  and an actuating member  100 . The bias element  90  has a proximal end  92  that is connected to a portion of the handle and a free end  94  that is spaced from the proximal end. In one embodiment, the proximal end of the bias element is received within the slot  72  defined within the spacer member  70 . When the bias element is received within the slot and the spacer member is connected proximate the back end of the handle, the free end  94  of the bias element extends generally toward the front end of the blade cavity. In one embodiment, a portion of the bias element may contact a portion of the elongate portion  76  of the spacer member when the actuating member is in a second position. As shown in FIG. 8, the bias element may be a conventional spring, such as, for example, a leaf spring, that is positioned within the blade cavity  26  so that the free end  94  of the bias element extends upwardly toward an upper edge  25  of the handle when the bias element is in an unloaded condition. Further, in one embodiment, the bias element  90  is housed within the blade cavity  26  such that the bias element lies substantially in a plane defined by the blade  30 .  
         [0026]    The actuating member  100  is pivotally connected to the handle intermediate the tang  32  of the blade and the spacer member  70 . The actuating member has a peripheral edge  102  and defines a first arm  104  generally extending toward the back end of the blade cavity and a second arm  106  generally extending toward the front end of the blade cavity. The actuating member  100  also defines a bore  108  intermediate the first and second arms that is constructed and arranged to receive a male projection or a conventional fastener to allow for rotational movement of the actuating member. In one embodiment, the actuating member  100  is housed within the blade cavity  26  such that the actuating member lies substantially in a plane defined by the blade  30 .  
         [0027]    In operation, at least a portion of the second arm  106  of the actuating member is placed in continuous urging contact with a portion of the edge  33  of the tang  32  of the blade in response to a force applied to the first arm  104  of the actuating member by the bias element  90 . At least a portion of the free end  94  of the bias element is in continuous urging engagement against a portion of the edge surface  102  of the first arm  104  of the actuating member.  
         [0028]    The actuating member  100  is movable between a first position, in which the blade is in its closed position, and a second position, in which a portion of the second arm, such as, for example, its end, contacts a portion of the drive surface  35  of the shoulder  34  to create a toggle point, or dead point such that the blade may be selectively locked in its open position. In the open position, the blade is selectively locked in the open position as chord AB defined in the shoulder of the tang and longitudinal axis BC defined in the second arm of the actuating member are co-axial. In this configuration, a torque applied to the blade  30  by attempting to move the blade toward the closed position cannot induce rotation of actuating member  100  or the blade  30 . In one embodiment, when the blade is in the open position and the actuating member is in its second position, the stop  36  of the tang of the handle contacts the stop pin  50 , which aids in selectively locking the blade in the open position.  
         [0029]    The bias element  90  and the actuating member  100  of the blade opening assembly  80  may assist in movement of the blade to the open position. In one embodiment, to open the blade, the knife  10  in a closed position is typically grasped with the back end  24  of the handle oriented toward the operator&#39;s wrist and the bottom edge of the handle resting the operator&#39;s palm. This allows the operator to use their thumb to engage the thumb extension  39  and apply rotational torque to the blade  30 . The pressure applied by the operator onto the thumb extension  39  causes the blade to rotate about the pivot pin  28  and exit the blade cavity  26 . When an equilibrium position is reached as the blade is lifted out of the blade cavity and the drive surface  35  of the blade rotates about the pivot pin  28  and with respect to the second arm  106  of the actuating member, the bias element and the actuating member exert an opening force onto the blade.  
         [0030]    The tension in the bias element  90  acts against the actuating member  100  when a portion of the drive surface  35  of the tang is positioned at a certain critical angle relative to the rotational axis of the blade, which in turn forces the actuating member to act against the tang of the blade to cause the blade to quickly move to the open position. Beyond the equilibrium position, the first arm  104  is forced to move in a first rotation direction R 1  due to a force vector applied by the tension applied by the bias element  90 . This rotational movement of the actuating member  100  forces a portion of the second arm  106  of the actuating member into urging contact against a portion of the drive surface  35  of the tang, which, in turn, causes the tang  32  of the blade to rotate in a second rotational direction R 2  until the blade  30  is in the open position and the actuating member  100  is in the second position. In one embodiment, the equilibrium position is reached when a portion of the drive surface  35  of the tang  32  is positioned overcenter relative to the rotational axis of the blade. It will be appreciated that the blade opening assembly  80  provides positive pressure to facilitate the movement of the blade to the open position. Only a limited amount of operator assistance is required, i.e., that required to move the blade to the equilibrium position.  
         [0031]    To close the knife, the first arm  104  of the actuating member may be depressed by the operator, in a third rotational direction R 3  that is opposite to the first rotational direction, to initiate movement of the actuating member from the second position to the first position. The initial movement of the actuating member  100  from the second position towards the first position spaces the portion of the second arm of the actuating member  100  from the portion of the drive surface  35  of the tang, which selectively disturbs or breaks the toggle point and, thus selectively unlocks the knife from its fully open position. The blade  30  of the knife can then by manually rotated by the operator into its closed position, which also places the actuating member  100  back into its first position.  
         [0032]    In one embodiment, a portion of the edge surface  102  of the first arm  104  of the actuating member may be positioned proximate the upper edge  25  of the handle when the actuating member is in the second position to facilitate movement of the first arm  104  of the actuating member in the third rotational direction R 3 . The upper edge  25  of the handle may also define a female recess  27  in the upper edge. If side members are used, the female recess  27  may be formed by a pair of spaced female recesses  27 ′,  27 ″ that are positioned in opposition to each other (one of the pair of female recesses defined in the upper edge of each of the side members). The female recess  27  adjoins a portion of the blade cavity and is constructed and arranged so that the portion of the edge surface  102  of the first arm  104  of the actuating member is positioned within the female recess  27  when the actuating member is in the second position. Typically, in the second position the edge surface of the first arm will not extend beyond the plane defined by the upper edge of the handle. In operation, the operator simply presses a portion of the first arm  104  into the recess  27  to initiate closing the blade of the knife.  
         [0033]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.