Abstract:
A folding knife including a knife blade pivotally secured to a knife handle in such manner as to permit the knife blade to be releasably locked in a closed position with respect to the handle and in practically any open position.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to knives and, more particularly, a hand-held folding knife which, in a preferred embodiment, can be locked in alternative blade orientations.  
         [0002]     Knives have been used and carried as tools and weapons since the earliest times of human existence. As the art and craft of knife making has developed, folding knives have been created as an alternative to fixed bladed knives which require a sheath for safe transport and handling.  
         [0003]     Modern examples of folding knives can be found in the recent patents to: Li Yu, U.S. Pat. No. 6,763,592 B2; Glesser, U.S. Pat. No. 6,751,868 B2; Cheng, U.S. Pat. No. 6,651,344 B2; Onion, U.S. Pat. No. 6,591,504 B2; Glesser, U.S. Pat. No. D461,387 S; Horn, U.S. Pat. No. Des. 387,966; and the publications of Chu, Pub. No. US 2004/0134075 A1 and Frazer, Pub. No. US 2003/0070299 A1. Each of these teaches a folding knife with various degrees of complexity.  
         [0004]     Examples of folding knives that are capable of being locked while in a fully open position include patents to Pittman, U.S. Pat. No. 5,615,484; Centofante, U.S. Pat. No. 5,964,036; and Glesser et al., U.S. Pat. No. 6,553,672 B2.  
         [0005]     What has been needed and which is supplied by the present invention, is a relatively simple folding knife with few parts and a simple, easily used mechanism for deploying the blade and for locking the blade in a fully open position, a fully closed position, and a plurality of partially open positions between the fully open and the fully closed positions.  
       SUMMARY OF THE INVENTION  
       [0006]     According to the present invention, a folding knife includes a knife blade pivotally secured to a knife handle in such manner as to permit the knife blade to be releasably locked in a closed position with respect to the handle and in practically any open position.  
         [0007]     According to one aspect of the present invention, a folding knife comprises: a knife handle including a lug guide; a pivot lock carried by the knife handle, the pivot lock including a blade pivot and a lug for the lug guide; a knife blade having a tang including a pivot hole and two lug slots, the blade pivot received by the pivot hole for enabling rotation of the knife blade about the blade pivot when the lug is disengaged from the lug slots, the knife blade locked in an open position with respect to the knife handle when the lug engages one of the lug slots and in a closed position when the lug engages the other of the lug slots; and a pushbutton carried by the handle and coupled to the pivot lock, the pushbutton biased for normally engaging the lug with the lug slots and for disengaging the lug from the lug slots when the pushbutton is depressed. The knife handle preferably includes a spring biasing the pushbutton in a direction away from the pivot lock for normally engaging the lug with the lug slots, the pushbutton being depressible against the bias of the spring for disengaging the lug from the lug slots. The two lug slots are preferably spaced apart by 180 degrees about the pivot hole. The tang may include at least one additional lug slot for being engaged by the lug when the knife blade is in a partially open position, the at least one additional lug slot preferably spaced from the two lug slots about the pivot hole.  
         [0008]     A preferred embodiment of a folding knife according to the present invention comprises: a knife handle including two lug guides; a pivot lock carried by the knife handle, the pivot lock including a blade pivot and two lugs for the lug guides; a knife blade having a tang including a pivot hole and two lug slots spaced about the pivot hole, the blade pivot received by the pivot hole for enabling rotation of the knife blade about the blade pivot when the lugs are disengaged from the lug slots, the knife blade locked in an open position with respect to the knife handle when one of the lugs engages one of the lug slots and the other of the lugs engages the other of the lug slots, the knife blade locked in a closed position when such one of the lugs engages such other of the lug slots and such other of the lugs engages such one of the lug slots; and a pushbutton carried by the handle and coupled to the pivot lock, the pushbutton biased for normally engaging the lugs with the lug slots and for disengaging the lugs from the lug slots when the pushbutton is depressed. The knife preferably includes a spring biasing the pushbutton in a direction away from the pivot lock for normally engaging the lugs with the lug slots, the pushbutton being depressible against the bias of the spring for disengaging the lugs from the slots.  
         [0009]     The two lug slots are preferably spaced apart by 180 degrees about the pivot hole. The tang may include at least one pair of additional lug slots spaced about the pivot hole for being engaged by the lugs when the knife blade is in at least one predetermined partially open position with respect to the knife handle. The lug slots of each of the at least one pair of additional lug slots are preferably spaced apart by 180 degrees.  
         [0010]     The knife handle preferably includes an elongate first scale including the lug guide, and an elongate second scale secured to the first scale and laterally spaced therefrom for accommodating the knife blade between the first scale and the second scale; the pivot lock is carried by the first scale; and the pushbutton is carried by the second scale.  
         [0011]     Depressing the pushbutton moves the lugs out of engagement with the lug slots, permitting the blade to rotate on the blade pivot. When the blade is in a desired orientation, as determined by aligning the lugs with the desired lug slots, the pushbutton is released and, under the bias of the spring, the lugs engage the lug slots, holding the blade in the selected orientation. Throughout pushbutton operation, the lugs move within, but are never free of, the lug guides in the first scale.  
         [0012]     The lug slots are typically arranged in opposed pairs that correspond to an opposed pair of lugs. The lug slots can be varied in number and can be further varied in their location around the blade&#39;s pivot hole. In one configuration, four pairs of opposed lug slots may be located about the pivot hole with the slots of one pair being at 0 and 180 degrees, respectively (i.e., substantially along the knife&#39;s longitudinal axis, for fully open or closed blade positions), the slots of the second pair at 45 and 225 degrees (for a partially open position), the slots of the third pair at 90 and 270 degrees (for another partially open position), and the slots of the fourth pair at 135 and 315 degrees (for yet another partially open position). The lug slots can be located in any other location around the pivot hole. The pivot lock is operable with one or more lugs.  
         [0013]     Accordingly, an object of this invention is to provide a simple folding knife that is easily manufactured and assembled. An additional object of this invention is to provide a folding knife that is easily deployed. It is a further object of this invention to have a folding knife with a blade that can be releasably locked in a closed position and in at least one open position of practically any degree of openness. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The novel features which are characteristic of the invention, both as to structure and method of operation thereof, together with further objects and advantages thereof, will be understood from the following description, considered in connection with the accompanying drawings, in which a preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purpose of illustration and description only, and is not intended as a definition of the limits of the invention.  
         [0015]      FIG. 1  is an exploded perspective view of a preferred embodiment of a folding knife in accordance with the instant invention;  
         [0016]      FIG. 2  is a front side view of the assembled knife embodiment of  FIG. 1 ; and  
         [0017]      FIG. 3  is a magnified cross-sectional view of a portion of the knife of  FIG. 2  taken along the line  3 - 3  in the direction of the appended arrows.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]      FIGS. 1-3  illustrate a typical preferred embodiment of a folding knife  18  of the instant invention. A knife handle  20  includes an elongate rear scale  21  attached to an elongate front scale  22 , such as by screws  23 , although rivets or other means could be employed to fasten the parts together. A spacer  24  between the rear scale  21  and the front scale  22  holds the rear scale  21  and front scale  22  at a fixed lateral distance and position with respect to one another sufficient to accommodate a knife blade  25  having a tang  26 . In this manner, the width of the spacer  24  controls the amount of friction or pressure applied to the tang  26  by the rear scale  21  and the front scale  22 .  
         [0019]     The rear scale  21 , spacer  24 , front scale  22 , and tang  26  are configured to collectively accommodate a lug assembly  27  that allows a user to lock the blade  25  of the knife in a closed position and in a plurality of open positions, including a fully open position and at least one partially open position where the knife blade  25  is rotated to a position other than a fully open position. The lug assembly  27  comprises a pivot lock  28 , a spring  29 , and a pushbutton  30 . The pivot lock  28  further comprises a blade pivot  31  and, as shown, a pair of lugs  32 ,  32 ′. The pushbutton  30  further includes a pivot retainer  33  and a spring cavity  46 . The spring cavity  46  is best seen in  FIG. 3 .  
         [0020]     The front scale  22  has a spring well  34  that further comprises a spring seat  35  and a front pivot hole  36 . The spring  29  resides in the spring well  34  and is located between the spring seat  35  and the spring cavity  46  of the pushbutton  30 . As can be seen in  FIG. 3 , the pivot retainer  33  passes through the front pivot hole  36  and is attached to the pivot lock  28  by a screw  44  or other means.  
         [0021]     The rear scale  21  has a hole  37  therethrough in which the blade pivot  31  resides. One or more lug guides  38  extend through the rear scale  21  near the rear scale hole  37  and are configured in location and number to receive the lugs  32 . The blade  25  has a pivot hole  39  in its tang  26  that allows the blade  25  to rotate on the blade pivot  31 . The tang  26  also has one or more lug slots  40  around the pivot hole  39 . The blade pivot  31  passes through the rear scale hole  37  and through the pivot hole  39  in the tang  26 . The blade pivot  31  is sufficiently long so that when the pushbutton  30  is fully depressed along the pivot axis against the bias of the spring  29 , fully displacing the lugs  32  from the lug slots  40  in the tang  26 , the blade pivot  31  remains within the blade&#39;s pivot hole  39 . The lugs  32  are of a length such that they are fully removed from the lug slots  40  but are still within the lug guides  38  when the pushbutton is fully depressed.  
         [0022]     In normal operation, the spring  29  outwardly biases the pushbutton  30  to correspondingly urge the attached pivot lock  28  to maintain the lugs  32  in engagement with the lug slots  40 , locking the blade  25  against rotation. A user fully depressing the pushbutton  30  against the bias of the spring  29  correspondingly moves the attached pivot lock  28  to disengage the lugs  32  from the lug slots  40 . In this state, the blade  25  is free to rotate about the blade pivot  31  and can be rotated to a closed position or to an open position as selected by the user, whereupon the user releases the pushbutton  30  to lock the blade  25  in the selected position.  
         [0023]     The embodiment shown allows a typical operation wherein two lugs  32 - 32 ′ collectively and simultaneously engage any one of four different pairs of lug slots  40   a - a ′,  40   b - b ′,  40   c - c ′ or  40   d - d ′. In the illustrated example, the two lugs  32 - 32 ′ are radially directed about the rear scale hole  37 , substantially along the longitudinal axis a of the knife  18 , and are rotationally spaced apart by 180 degrees. Each of the slots  40  through the tang  26  are radially directed about the pivot hole  39 , and the slots  40  of each pair of slots are spaced apart by 180 degrees for receiving the two lugs  32 - 32 ′. The pairs of slots  40  may be uniformly rotationally spaced about the pivot hole  39 ; in the illustrated example of four slot pairs, the successive slot pairs may be separated by 45 degrees.  
         [0024]     One of the slot pairs (e.g. slot  40   a  and  40   a ′) is oriented with respect to the lug guides  38  and  38 ′ (which are in correspondence with the lugs  32  and  32 ′, respectively) such that the blade  25  is in its fully open position (substantially along the knife&#39;s longitudinal axis a) when the blade  25  has been rotated with lug  32  received by slot  40   a  and lug  32 ′ received by slot  40   a ′, and the blade  25  is in its closed position (also substantially along the knife&#39;s longitudinal axis a) when the blade  25  has been rotated with lug  32  received by slot  40   a ′ and lug  32 ′ received by slot  40   a.    
         [0025]     Similarly, the blade  25  is open 45 degrees from the closed position when lugs  32  and  32 ′ engage, respectively, lug slots  40   d  and  40   d ′, the blade  25  is open 90 degrees from the closed position when lugs  32  and  32 ′ engage, respectively, lug slots  40   c  and  40   c ′, and the blade  25  is open 135 degrees from the closed position when lugs  32  and  32 ′ engage, respectively, lug slots  40   b  and  40   b ′. The number and location of the lugs  32 , lug guides  38 , and lug slots  40  can all be varied so that practically any degree of open position can be obtained. The folding knife can be fully operational with one or more lugs  32  engaging one or more lug slots  40 .  
         [0026]     The blade  25  has a back edge  41  and a stop notch  42  between the back edge  41  and the tang  26 . When the blade  25  is rotated to a fully open position 180 degrees from the closed position, the stop notch  42  makes contact with a stop tip  43  on the spacer  24 . This contact prevents the blade from rotating beyond the fully open position. If the blade is to rotate more than 180 degrees beyond the closed position, the stop notch  42 , or stop tip  43 , or both may be omitted from the structure.  
         [0027]     The disclosed knife embodiment and its various components may be manufactured using fabrication methods and of materials well known in the art. For example, the knife blade is preferably fabricated of steel, and the scales and other components may be fabricated of metallic materials such as steel, titanium or aluminum alloys, or of polymeric materials. If desired, a single-piece knife handle including the scales and spacer may be made by milling a single piece of stock, by forming it from a mold, or by other means known in the art.  
         [0028]     The foregoing description is for illustrative purposes only. It will be apparent to those skilled in the art that various changes and modifications can be made to the instant invention without departing from the overall spirit and scope of the instant invention. It is in that context that the following claims are made.