Patent Publication Number: US-6212779-B1

Title: Knife with pivotally mounted blade

Description:
BACKGROUND OF THE INVENTION 
     Folding knives are well known in the art and serve a variety of uses, with the primary purpose of the folding feature being to conceal the sharpened edge of the blade so that the knife may be safely carried without an additional cover or sheath. An additional purpose is to reduce the overall length of the knife for more convenient carrying. 
     Numerous designs of folding knives have been developed in the past, both of the locking and non-locking variety. The primary benefits of the simple, non-locking foldable knife are its simplicity and economy, since there is usually only one principal moving part, the blade. However, any inability to lock the blade in its extended position places serious limitations on the use of such a knife for purposes such as self defense and other demanding activities. 
     Locking foldable or retractable knives have taken many forms, including blades which slide out of the handle and lock, and pivoting blades which are released and locked by one or more mechanisms operated by the user. While such knives have broad utility and are available in many forms, they usually suffer from one or more of the following deficiencies: inability to accommodate a blade with more than one sharpened edge; inability to be opened or closed with either hand; awkward or unreliable operation of the blade locking mechanism; inability to be quickly and easily disassembled for maintenance or repair; and susceptibility to contaminants which could render the knife inoperable. Therefore, despite the long and continued development of folding knives capable of being positively locked in the open position, there still exists the need for a knife of economical construction which can satisfactorily overcome the aforementioned deficiencies of contemporary folding knives. 
     SUMMARY OF THE INVENTION 
     In accordance with this invention I have provided a novel folding knife having a pivotally mounted blade, with this knife utilizing two elongate handle members. When fitted together, these handle members form a mounting means for pivotal movement of the blade and safely enclose the blade when the knife is not in use and in addition, provide a means for grasping the knife when the blade is in the extended position. 
     Each of the elongate handle members provided in accordance with this invention has an internal surface and an external surface, with a protrusion located on the internal surface of each elongate handle member, adjacent one end of the handle member. The protrusion is disposed on only one side of a longitudinal centerline extending along the internal surface of each elongate handle member, with the part of the protrusion remote from the longitudinal centerline having an essentially semi-circular surface. An aperture is defined in each elongate handle member, disposed on the longitudinal centerline and located closely adjacent the protrusion. 
     When the elongate handle members have been fitted together, the protrusions define a substantially circular component, suitable for the mounting of a pivotally movable blade. 
     The blade is elongate with the sharpened edges originating at one end and a circular aperture adjacent the other end, with the aperture of the blade being of a diameter such that it can be closely received upon the protrusions when the protrusions have been juxtaposed so as to form the substantially circular component. 
     Significantly, the elongate handle members may be moved apart for a limited extent by the user, so as to make possible the pivotal movement of the blade into its extended position. When in such extended position, it will be strongly held and restrained against undesirable movement. 
     Instead of necessitating an expensive or complicated spring mechanism for causing the elongate handle members to be biased together when the blade is either in the folded or the extended position, my novel design permits the highly advantageous use of a compression spring of straightforward construction, thus assuring that my knife can be produced economically, and the spring easily replaced should such ever become necessary. An actuating disk is disposed in each handle member, with the simultaneous depression of the actuating disks bringing about the compression spring being compressed. 
     It will hereinafter be seen that I utilize two pairs of alignment pins of essentially cylindrical configuration and through contact with the respective actuating disk, each pair of alignment pins is pushed into contact with the base portion of the blade, so that when the actuating disks have been fully depressed, the alignment pins positively locate the blade in a centered position between the elongate handle members, which permits the blade to freely rotate from the folded position into the extended position, or from the extended position into the folded position. 
     Additionally, my novel design of the handle members is such that a multi-edged blade, rather than merely a single edged blade, can be accommodated. 
     It is therefore a primary object of my invention to provide a folding knife of economical construction that advantageously may be safely and conveniently opened or closed by one handed operation. 
     It is another object of my invention to provide a folding knife having handle members biased together by spring means to safely enclose the blade, with these handle members being movable apart for a limited extent when it is desired to deploy the blade, with the handle members then reclosing under the bias of the spring means to firmly and securely hold the blade in the extended position when the blade is to be put into use. 
     It is still another object of my invention to provide a folding knife involving a minimal number of components, with a pair of alignment pins utilized on each side of the blade to serve a blade centering purpose, thus to cause the blade to reside essentially equidistant from the handle members when the handle members have been moved apart. 
     These and other objects, features and advantages will become more apparent as the description proceeds. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of the novel elongate handle members of my knife, with the protrusions that are juxtaposed to form a support means for the knife blade being made apparent, with this view also making clear that I am advantageously able to use a compression spring for biasing the elongate handle members together; 
     FIG. 2 a  is a view which depicts the position of the knife blade when in its folded position, as well as one of the two actuating disks that are to be pressed together when the knife blade is to be moved either to the folded or the extended position; 
     FIG. 2 b  is a view which depicts the position of the knife blade when in its extended position, with this view making clear that a multi-edged blade may be utilized in accordance with this invention; 
     FIG. 3 a  is an end view of my novel knife, to a substantially larger scale, with this view revealing not only the placement of the compression spring, but also how the shoulder of one handle member is normally biased into contact with the shoulder of the adjacent handle; and 
     FIG. 3 b  is an end view closely related to FIG. 3 a , but here showing how the shoulders are momentarily caused to move apart to permit rotation of the knife blade at such time as the user has caused the actuating disks to move simultaneously inward and to bring about further compression of the compression spring. 
    
    
     DETAILED DESCRIPTION 
     With initial reference to FIG. 1 it will be seen that I have shown in exploded form, a novel knife  10  in accordance with this invention, involving a pivotally mounted blade  12  having sharpened edges  14  and  16 . The base portion  18  of the blade is provided with an aperture  20  serving as the mounting means for the blade. The terminus  21  of the blade may be either pointed or rounded, and the blade may be constructed of any suitable material upon which sharpened edges can be maintained. 
     Operatively associated with the blade  12  is a first elongate handle member  22  and a second elongate handle member  24 . The handle members  22  and  24  are intended to be fitted together so as to represent an effective containment means for the blade  12  when the blade is not in use; note FIG. 2 a.    
     As will shortly be explained in greater detail, the elongate handle members  22  and  24  can momentarily be moved apart for a limited extent so as to permit the blade  12  to be rotated into the extended position depicted in FIG. 2 b.  The assembled elongate handle members  22  and  24  form at that time a sturdy and highly effective grip, simplifying the manipulation and usage of the blade  12 . 
     Certain significant aspects of the construction of my novel knife are to be noted in FIG. 1, with it there being revealed that the elongate handle member  24  has an essentially flat internal surface  25 , with an upstanding protrusion  44  located adjacent one end thereof. Also to be noted is the fact that extending around a substantial portion of the perimeter or marginal edge of the elongate handle member  24  is a shoulder  28 . More particularly, I prefer for the shoulder  28  to extend down both of the long edges of the handle member  24  and then curve around the end of the handle member opposite from the location of the protrusion  44 . 
     It is to be understood that the elongate handle member  22  is closely similar to the handle member  24 , with a shoulder  26  extending around a substantial portion of the perimeter or marginal edge of the elongate handle member  22 . Although the shoulder  26  is not clearly visible in FIG. 1, it is to be understood that the shoulder  26  extends around the internal surface  23  (not shown in this figure) of the handle member  22  in an essentially identical manner as the shoulder  28  extends around the periphery of the internal surface  25  of the handle member  24 . 
     Continuing with handle member  22 , it is to be noted that projecting perpendicularly upward from the internal surface  23  of elongate handle member  22  is a protrusion  42 . It is important to note that the protrusion  42  as well as the protrusion  44  forming an intrinsic part of the handle member  24  have surfaces permitting the protrusions to be placed in an abutting, relatively slidable relationship when the handle members have been placed in juxtaposition; note FIGS. 3 a  and  3   b.    
     Both of the substantially identical protrusions  42  and  44  project for a relatively short distance perpendicularly from the internal surface of the respective handle member, and quite significantly, each of the protrusions is disposed on only one side of a longitudinal centerline  40  extending along the internal surface of each elongate handle member. The centerline  40  is visible on the internal surface  25  of the handle member  24  as viewed in FIG.  1 . Also to be noted is the fact that the part of each of the protrusions remote from the longitudinal centerline has an essentially semi-circular surface. In FIG. 1 it will be seen that protrusion  42  of handle member  22  has an essentially semi-circular surface  43 , and protrusion  44  of handle member  24  has an essentially semi-circular surface  45 . 
     It is important to observe that an aperture is defined in each elongate handle member closely adjacent the respective protrusion, with aperture  46 , clearly visible in FIG. 1, being located adjacent the upstanding protrusion  42  of handle member  22 . Similarly, aperture  48  is defined in handle member  24  adjacent the upstanding protrusion  44 . When viewed from the interior of the handle member, each of the apertures  46  and  48  is approximately the same size as the adjacent protrusion, but when each aperture is viewed from the exterior of the respective handle member, it is seen to be circular, for a purpose shortly to become apparent. Each aperture is located on the longitudinal centerline of the respective handle member. 
     The elongate handle members  22  and  24  are capable of being interfitted in a relatively movable manner and when interfitted, the pair of protrusions  42  and  44  form a highly satisfactory mounting means for the knife blade  12 . It has already been mentioned that the surface of each protrusion remote from the centerline  40  is essentially semi-circular, with the result being that when the protrusions  42  and  44  have been caused to reside closely together, the essentially semi-circular surfaces  43  and  45  form a substantially circular component, which is of consequence from the standpoint of a desirable blade support. The protrusions  42  and  44  are of sufficient length that they continue to form an effective mounting means for the knife blade even when the protrusions have undertaken relative movement in a slidable manner as a consequence of the handle members moving apart for a limited extent. 
     With reference to FIGS. 3 a  and  3   b , it will be noted that the base portion  18  of the knife blade adjacent the aperture  20  is revealed in cross section, and it will be apparent from these figures that portions of the base of the knife blade are depicted on each side of the protrusions  42  and  44 . When the handle members have been caused to move away from the compacted relationship illustrated in FIG. 3 a  and into the somewhat separated positions depicted in FIG. 3 b , it is readily possible for the knife blade  12  to be moved from the folded or retracted position into the extended position depicted in FIG. 2 b.    
     With reference back to FIG. 1, it will be seen that I have illustrated actuating disks  32  and  34 . The disk  32  is to be secured to the protrusion  42  of the elongate handle member  22 , such as by a pair of small screws  52 , at such time as the handle members have been interfitted and the protrusion  42  has been caused to reside in aperture  48  in the handle member  24 . In a like manner, the actuating disk  34  is to be secured to the protrusion  44  of the elongate handle member  24  by a pair of small screws  54  when the handle members have been interfitted and the protrusion  44  has been caused to reside in aperture  46  in the handle member  22 . 
     Each of the disks is of course equipped with a suitable pair of small holes to receive the aforementioned small screws, and each of the protrusions is provided with threaded holes that line up with the holes in the actuating disks. I provide tapped holes in protrusion  42  (not visible in FIG. 1) to receive the small screws  52 , and I provide tapped holes  64  in protrusion  44  to receive the small screws  54 , with the small screws  52  and  54  being tightly received in the respective threaded holes. Each of the operating disks is of a slightly smaller diameter than the aperture in which it is operatively disposed. 
     It is thus to be understood that after the handle members have been moved into the interfitting relationship, the actuating disk  32  is operatively disposed in the aperture  48  located in the second elongate handle member  24 , and the actuating disk  34  is operatively disposed in the aperture  46  located in the elongate handle member  22 . 
     A mid portion of the protrusion  44  is configured to define an elongate recess  58  and a like recess is defined in the protrusion  42  such that when the protrusions reside in a relatively movable juxtaposed relationship, the compression spring  30  can be accommodated between the protrusions. The spring  30  extends between the actuating disks  32  and  34  and resides in contact with the interior surface of each disk. Because, in a manner of speaking, each actuating disk is secured to the “opposite” handle member, the compression spring  30  serves to bias the handle members  22  and  24  together rather than apart. 
     It is thus to be seen that the actuating disks  32  and  34 , when simultaneously depressed, cause a further compression of the spring  30  and the moving apart of the elongate handle members for a limited extent, in the manner depicted in FIG. 3 b . At the time of the cooperative movement of the actuating disks in the inward direction it becomes readily possible for the blade to be moved in a pivotal manner around the substantially circular support means formed by the interfitted protrusions  42  and  44 . 
     With reference back to FIG. 1, it will be noted that the base portion  18  of the blade  12  has straight sides, such that the blade  12  will be held tightly between the shoulders  26  and  28  when the handle members  22  and  24  are in contact with one another. Because of this, the blade of my novel knife is held very stably in the extended position. To be understood is the fact that only when the elongate handle members  22  and  24  have been caused to move apart to the limited extent to be noted from FIG. 3 b  will it be possible for the knife blade  12  to be rotated either to its extended position or back to its folded position. 
     It is thus to be understood that the spring means  30 , visible in FIGS. 1,  3   a  and  3   b , normally bias the elongate handle members into a closely fitted relationship, with the elongate handle members being moved apart by the user, against the bias of the spring  30 , for a distance slightly exceeding blade thickness at such time as the user simultaneously presses upon the actuating disks  32  and  34 . 
     It is to be noted from FIG. 1 that in addition to the previously mentioned components, I have depicted in this figure a pair of alignment pins  72 , closely associated with protrusion  42 , and a pair of alignment pins  74 , closely associated with protrusion  44 . Each of the alignment pins is of essentially cylindrical configuration, with suitable bores (not visible) being provided in the protrusion  42  and handle member  22  to receive the alignment pins  72 , and bores  75  provided in protrusion  44  and handle member  24  to receive the alignment pins  74 . It is the purpose of the alignment pins to contact the portion of the base portion  18  of the blade  12  in the vicinity of the aperture  20 , thus to cause the blade to reside essentially equidistant from the handle members when the handle members have been moved apart into the relationship depicted in FIG. 3 b.    
     It is thus to be understood that through contact with the respective actuating disk, each pair of alignment pins is driven through its respective bore into contact with the base portion of the blade. When the actuating disks  32  and  34  have been fully depressed in the manner depicted in FIG. 3 b , the alignment pins positively locate the blade in a centered position between the elongate handle members, which permits the blade to freely rotate from the folded position into the extended position, or from the extended position back into the folded position. 
     Although in the preferred embodiment of my invention, I prefer the use of the two pairs of alignment pins for blade centering purposes, I am not to be restricted to this arrangement. In some instances it may be possible or desirable to use other blade centering means, such as a conically-tapered compression spring situated around the protrusions and located on each side of the base portion  18  of the blade  12 . 
     From referring to FIGS. 3 a  and  3   b , the operation of my knife should be quite apparent, with it to be noted that in FIG. 3 a  I have shown the coiled spring  30  serving to hold the actuating disks  32  and  34  apart. In this instance, it will be noted that protrusions  42  and  44  are disposed in what may be regarded as an offset relationship, brought about by the bias provided by the spring  30 . It is also to be noted from each side of FIG. 3 a  that the shoulder  26  on the handle member  22  is in firm contact with the shoulder member  28  on the handle member  24 . With regard to FIG. 3 a , the appearance is the same whether the knife blade is in the extended or retracted position. 
     With reference now to FIG. 3 b , it is there illustrated how the actuating disk  32 , which is secured to protrusion  42 , and the actuating disk  34 , which is secured to protrusion  44 , have been moved simultaneously in the inward direction, thus causing the spring  30  to become further compressed, and the protrusions to be moved from the offset relationship into what may be regarded as the aligned relationship depicted in FIG. 3 b.    
     Of considerable consequence is the fact that in FIG. 3 b  I have shown the shoulders  26  and  28  having been momentarily moved apart so as to create a space sufficiently adequate that the knife blade  12  can be rotated in a pivotal manner about the protrusions  42  and  44 , and into the extended relationship depicted in FIG. 2 b.    
     At this point the user releases the actuating disks  32  and  34  which move, under the influence of the spring  30 , back into the separated relationship depicted in FIG. 3 a . At this time the shoulders  26  and  28  return to the touching relationship, with the blade being either held firmly in an extended position, or else encapsulated in a retracted position. It is to be noted that when the blade is in the retracted position, the shoulders moving into touching contact amounts to a relationship in which the blade is fully enclosed in a safe manner.