Patent Publication Number: US-2022219341-A1

Title: Folding Knife Safety Mechanism

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/814,642 filed Mar. 10, 2020, which claims priority to U.S. Provisional Application No. 62/816,748 filed Mar. 11, 2019, each of which is titled “Folding Knife Safety Mechanism” and each of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of knives. The present invention relates specifically to a knife, such as a folding knife, that includes a sliding lock to restrain the blade within the handle. 
     SUMMARY OF THE INVENTION 
     According to one embodiment, a folding knife includes a handle, an internal cavity defined by the handle, a blade rotatably coupled to the handle, a sliding lock slidably coupled to the handle, and a locking spring. The blade rotates with respect to the handle into and out of the internal cavity between a retracted position and an extended position. The locking spring is coupled to the handle. A first end of the locking spring interfaces with a recess defined by the blade, such as a notch, when the blade is in the retracted position. The locking spring interfaces against the sliding lock and biases the sliding lock away from a tip of the blade when the blade is in the retracted position. 
     According to another embodiment, a folding knife includes a handle including a top and a bottom opposite the top, an internal cavity defined by the handle, a blade rotatably coupled to the handle, a locking spring coupled to the handle, and a sliding lock slidably coupled to the handle. The blade rotates with respect to the handle into and out of the internal cavity between a retracted position and an extended position out of the bottom of the handle. The blade defines a recess, such as at a tang of the blade opposite the tip of the blade. The locking spring includes a middle portion that protrudes towards the bottom of the handle. A first end of the locking spring is within the recess when the blade is in the retracted position. The sliding lock interfaces against the middle portion of the locking spring. 
     According to another embodiment, a folding knife includes a handle, an internal cavity defined by the handle, a blade rotatably coupled to the handle, a locking spring coupled to the handle, and a sliding locking slidably coupled to the handle. The blade rotates with respect to the handle into and out of the internal cavity between a retracted position and an extended position. The blade defines a recess, such as at a tang of the blade opposite the tip of the blade. The locking spring defines a first end and a second end. The first end of the locking spring is within the recess of the blade when the blade is in the retracted position, and the second end of the locking spring defines a V-shape. 
     According to one embodiment, a folding knife includes a handle and a blade pivotably coupled to the handle via a pivot screw. The handle has an internal cavity with an opening that the blade pivots into and out of the internal cavity. The tang of the blade is coupled to the pivot screw to pivot between a retracted position, an extended position, and a range of intermediate positions. The folding knife includes a locking spring and a sliding lock to restrict opening of the blade from the retracted position. One end of the locking spring is rigidly coupled to the knife handle, and the other end of the locking spring includes an extension that interfaces against the tang of the blade. The tang of the blade has a notch that the locking spring extension is within when the blade is in the closed and locked position. The notch includes a locking wall that interfaces against the locking spring extension when a user attempts to rotate the blade out of the retracted position. In one embodiment the locking wall of the notch is collinear with a radial line extending from a center of the pivot screw. 
     Additional features and advantages will be set forth in the detailed description which follows, and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description included, as well as the appended drawings. It is to be understood that both the foregoing general description and the following detailed description are exemplary. 
     The accompanying drawings are included to provide further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain principles and operation of the various embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-3  are several side views of a knife, according to an embodiment. 
         FIGS. 4-5  are several cross-section views of the knife of  FIG. 1 . 
         FIG. 6  is a detailed perspective view of the knife of  FIG. 1 . 
         FIG. 7  is a detailed perspective view of the knife of  FIG. 1 . 
         FIGS. 8-11  are several cross-section views of the knife of  FIG. 1  transitioning from a closed position to an opened position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring generally to the figures, various embodiments of a knife and elements thereof are shown. Various embodiments of a knife discussed herein relate to a folding knife and a mechanism for securing the blade within the handle. The knife includes a sliding lock that locks a folding knife in the closed position via a unique interface between the sliding lock and the blade. The interface between the sliding lock and the blade minimizes the chances of the blade being opened accidentally while still permitting the blade to be removed from the handle when a user performs a deliberate series of steps to disengage the sliding lock with the blade. This helps prevent injuries occurring because the blade was unexpectedly exposed. 
     Referring to  FIGS. 1-3 , a knife, such as a folding knife  10 , is shown according to an exemplary embodiment. In general, folding knife  10  comprises blade  20  and handle  60 . Blade  20  is rotatably coupled to handle  60  such that blade  20  rotates around longitudinal axis  12  centered on pivot screw  14  with respect to handle  60 . Pivot screw  14  passes through pivot screw hole  70 . 
     In one embodiment, handle  60  defines internal cavity  68  within which blade  20  is retracted. In a specific embodiment handle  60  comprises first side shell  62  and second side shell  64 . Blade  20  rotates with respect to handle  60  into and out of internal cavity  68  between a retracted position and an extended position. Handle  60  defines a bottom  80  and a top  82  opposite the bottom  80 , and blade  20  rotates out of bottom  80  of handle  60 . When knife  10  is in the retracted position, blade  20  is closed within internal cavity  68  so that cutting edge  24  and tip  26  are safely secured. Sliding lock  54  is slidably coupled to handle  60 . Sliding lock  54  secures blade  20  within internal cavity  68  when blade  20  is in the closed and locked position. 
     Referring to  FIGS. 4-7 , locking spring  42  interfaces with tang  22  of blade  20  to lock blade  20  in the closed position. Tang  22  of blade  20  is opposite tip  26  of blade  20 . Sliding lock  54  interfaces against locking spring  42  to selectively disengage locking spring  42  from notch  28 , which frees blade  20  to pivot into the open position (e.g., where edge  24  and tip  26  are rotated from handle  60 ). Stated another way, locking spring  42  interfaces against the sliding lock  54  and biases the sliding lock  54  away from tip  26  of blade  20  when blade  20  is in the retracted position. 
     In a specific embodiment, sliding lock  54  interfaces against middle portion  49  of locking spring  42 . Middle portion  49  protrudes away from top  82  of handle  60  towards bottom  80  of handle  60 . 
     Fixed end  44  of locking spring  42 , shown in  FIG. 7  as comprising a V-shape, is rigidly coupled to handle  60 . In one embodiment, locking spring  42  is fixedly coupled to one of first side shell  62  and second side shell  64  of handle  60 . In another embodiment, locking spring  42  is fixedly coupled to both first side shell  62  and second side shell  64 . Free end  46  of locking spring  42  is biased to engage within notch  28  and interface with notch  28  when blade  20  is in the retracted position (shown in  FIGS. 6-7 ), thus biasing blade  20  towards the retracted position. Free end  46  of locking spring  42  pivots with respect to fixed end  44 . In a specific embodiment notch  28  is at tang  22  of blade  20 , and thus free end  46  of locking spring  42  interfaces against tang  22  of blade  20 . 
     Turning to  FIGS. 8-11 , illustrated therein are a series of steps to transition folding knife  10  from a locked and retracted position to an unlocked and extended position. Starting at  FIG. 8 , blade  20  is in the closed position within handle  60 . Free end  46  of locking spring  42  biases towards pivot screw  14 , and as a result locking extension  50  of locking spring  42  interfaces with a recess within blade  20 , shown as notch  28 , when blade  20  is in the retracted position. Sliding lock  54  is biased away (to the left in  FIG. 8 ) from displacement wall surface  48  in direction  56  away from tip  26  of blade  20 . If a user were to attempt to rotate blade  20  clockwise from the perspective of  FIG. 8 , locking wall surface  30  of notch  28  would interface against free end  46  of locking spring  42  to exert an increasing biasing force against blade  20  rotating clockwise out of handle  60 . In at least one embodiment locking wall surface  30  of notch  28  is radially aligned with respect to longitudinal axis  12  at the center of pivot screw  14 . 
     Turning to  FIG. 9 , a user forces sliding lock  54  along sliding lock aperture  66  towards and against displacement wall surface  48 . Displacement wall surface  48  is angled with respect to sliding lock aperture  66  so that the interface between sliding lock  54  and displacement wall surface  48  forces free end  46  of locking spring  42  to pivot away from pivot screw  14  and disengage from notch  28 . The amount of force necessary to displace free end  46  from notch  28  is a function of several aspects, including the angle of displacement wall surface  48  with respect to sliding lock aperture  66  and the thickness  52  of locking spring  42  (e.g., its resistance to being deformed). To reduce the force necessary to unlock sliding lock  54 , the thickness  52  of locking spring  42  may be decreased and/or the angle between displacement wall surface  48  and sliding lock aperture  66  can be reduced (e.g., displacement wall surface  48  may be adjusted further from perpendicular and closer to collinear with respect to sliding lock aperture  66 ). 
     Turning to  FIG. 10 , after free end  46  is disengaged from notch  28 , blade  20  is rotated clockwise from the perspective of  FIG. 10 . As a result, cutting edge  24  and tip  26  of blade  20  are exposed outside of handle  60 . In a specific embodiment free end  46  of locking spring  42  does not interface with blade  20  when blade  20  is in the extended position. 
     Turning to  FIG. 11 , after blade  20  is fully opened, sliding lock  54  is biased to the left (from the perspective of  FIG. 11 ) and interfaces against upper surface  32  of tang  22 . The interface between upper surface  32  and sliding lock  54  exerts a biasing force against blade  20  from being rotated towards the closed position (e.g., blade  20  rotating counter-clockwise from the perspective of  FIG. 11 ). In this position, free end  46  of locking spring  42  is idle. To start closing blade  20  from the open position, sliding lock  54  is slid to the right from the perspective of  FIG. 11  until sliding lock  54  is clear of upper surface  32  and blade is free to rotate counter-clockwise, again from the perspective of  FIG. 11 . 
     It should be understood that the figures illustrate the exemplary embodiments in detail, and it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for description purposes only and should not be regarded as limiting. 
     Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements, shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention. 
     Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more component or element, and is not intended to be construed as meaning only one. As used herein, “rigidly coupled” refers to two components being coupled in a manner such that the components move together in a fixed positional relationship when acted upon by a force. 
     Various embodiments of the invention relate to any combination of any of the features, and any such combination of features may be claimed in this or future applications. Any of the features, elements or components of any of the exemplary embodiments discussed above may be utilized alone or in combination with any of the features, elements or components of any of the other embodiments discussed above.