Patent Publication Number: US-7581321-B2

Title: Folding knife

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   The present application claims the benefit of U.S. Provisional Application No. 60/734,551, filed Nov. 7, 2005, which is incorporated herein by reference. 

   FIELD 
   The present invention relates to a folding knife, and in particular, a folding knife having a locking mechanism that rotates with the blade. 
   BACKGROUND 
   One form of conventional sport or work knives comprises a handle and one or more folding blades. The blades in such knives are closed simply by pressing on the back of the blade and rotating the blade to a closed position in the knife handle. Such knives are known for their ability to close when being used if a pressure is inadvertently applied to the back of the blade. 
   To protect against inadvertent closure, various types of locks were developed for locking a blade in an open position. A common type of locking element known as a liner lock extends longitudinally through the handle and is spring biased to snap into position adjacent to the hinged end (tang) of the blade when the blade is opened. A projecting portion of the locking element or other release mechanism is manipulated to manually move the locking element laterally away from the blade swing path so that the blade can be closed. 
   Further, various mechanisms have been developed to facilitate opening and/or closing of the blade of a conventional folding knife. Typically, the blade is provided with a thumb stud that can be manipulated by the user to open and close the blade. 
   Despite the long and continued development of folding knives, it would be desirable to provide a folding knife with a novel blade-locking mechanism and/or novel blade-opening mechanism. 
   SUMMARY 
   In one aspect, the present disclosure concerns a folding knife having a locking mechanism coupled to the blade such that pivoting the blade from the closed position to the open position, and vice versa, causes corresponding rotation of the locking mechanism about the pivot axis of the blade. The locking mechanism is operable to selectively lock the blade in the open position and optionally to selectively lock the blade in the closed position. In particular embodiments, the locking mechanism is a bolster of the knife handle. The locking mechanism can be slid longitudinally of the blade between a first, locked position to lock the blade in the open or closed positions and a second, unlocked position to permit pivoting of the blade. When the locking mechanism in this embodiment is in the locked position, it abuts an adjacent side panel of the knife so as to resemble a conventional bolster. 
   The handle can be provided with a locking element, such as in the form of a locking pin, that is positioned to engage a corresponding surface of the locking mechanism when it is slid to the locked position, thereby preventing pivoting of the blade. In certain embodiments, first and second notches for engaging the locking pin can be formed on opposite sides of the locking mechanism. When the blade is in the closed position, the locking mechanism can be slid to the locked position to engage the locking pin in the first notch, thereby locking the blade in the closed position. Opening the blade causes the locking mechanism to rotate 180 degrees about the pivot axis. In this position, the locking mechanism can be slid to the locked position to engage the locking pin in the second notch, thereby locking the blade in the open position. 
   The locking mechanism in exemplary embodiments can be coupled to the blade by a pivot element disposed in the handle and extending through an opening in a tang portion of the blade and into an opening of the locking mechanism. The pivot element can be formed with a non-circular cross-sectional profile, such as an oblong profile, where it extends through the tang portion and into the locking mechanism. The opening in the tang portion is shaped to correspond to the shape of the pivot element so that pivoting movement of the blade causes corresponding rotation of the pivot element. The pivot element also engages the sides of the slot in the locking mechanism so that pivoting movement of the blade causes rotation of the pivot element and the locking mechanism about the blade pivot axis. Conversely, rotation of the locking mechanism is effective to cause corresponding pivoting movement of the blade. In this manner, the locking mechanism can be used as an opening and closing mechanism for the blade. The slot in the locking mechanism also is dimensioned to allow the locking mechanism to be slid relative to the pivot element in a direction perpendicular to the pivot axis between the locked and unlocked positions. 
   In one representative embodiment, a folding knife comprises a handle portion having a locking pin and a blade having a tang portion pivotably coupled to the handle portion. The blade is pivotable relative to the handle portion between a closed, or folded, position and an open, or extended, position. The knife can also include a locking mechanism coupled to the tang portion of the blade such that the locking mechanism is caused to pivot with the blade when the blade is opened or closed. The locking mechanism is slidable relative to the handle portion and the blade between a rearward position engaging the locking pin to prevent pivoting of the blade from the open position and a forward position spaced from the locking pin to allow for pivoting movement of the blade. 
   In another representative embodiment, a folding knife comprises a handle portion and a blade having a tang portion pivotably coupled to the handle portion. The blade is pivotable relative to the handle portion between a closed, or folded, position and an open, or extended, position. A locking mechanism can be coupled to the tang portion of the blade such that the locking mechanism is caused to pivot with the blade when the blade is opened or closed. The knife can also include a pivot element defining a pivot axis for the blade and the locking mechanism. The pivot element can be disposed in the handle portion and can extend through the tang portion and into an opening in the locking mechanism. The locking mechanism is slidable relative to the pivot element between a first, locked position to prevent pivoting of the blade from the open position and a second, unlocked position to allow for pivoting movement of the blade. 
   In another representative embodiment, a folding knife comprises a handle portion and a blade having a tang portion coupled to the handle portion. The blade is pivotable relative to the handle portion between a closed, or folded, position and an open, or extended, position. The knife can further include a blade locking member that is pivotable 180 degrees with the blade when the blade is pivoted between from the open position to the closed position and vice versa. A pivot element, defining a pivot axis extending through the locking member, is disposed in the handle portion and extends through the tang portion. When the blade is in the open position, the locking member can be moved longitudinally of the blade between a first, locked position to prevent pivoting of the blade and a second, unlocked position to allow the blade to be pivoted to the closed position. 
   In still another representative embodiment, a folding knife comprises a handle portion having a blade locking mechanism and a blade having a tang portion coupled to the handle portion. The blade is pivotable relative to the handle portion between a closed, or folded, position and an open, or extended, position. A pivot element defines a pivot axis for the blade and can have a portion extending through a non-circular opening in the tang portion, said portion of the pivot element having a non-circular cross-sectional profile which causes the pivot element to rotate about the pivot axis upon pivoting movement of the blade. The locking mechanism can be connected to the pivot element and can be operable to rotate about the pivot axis to cause corresponding rotation of the pivot element and pivoting movement of the blade about the pivot axis. The locking mechanism can be moved relative to the pivot element in a direction perpendicular to the pivot axis between a first, locked position to prevent pivoting of the blade from the open position and a second, unlocked position to allow the blade to be pivoted to the closed position. 
   In another representative embodiment, a folding knife comprises a handle portion and a blade having a tang portion pivotably coupled to the handle portion. The blade is pivotable relative to the handle portion between a closed, or folded, position and an open, or extended, position. A pivot element extends through the tang portion of the blade and defines a pivot axis. The pivot element is adapted to rotate about the pivot axis upon pivoting movement of the blade. The knife can also include a blade-opening mechanism connected to the pivot element and being operable to rotate about the pivot axis to cause corresponding pivoting movement of the blade. The blade-opening mechanism is moveable relative to the pivot element and the blade in a direction perpendicular to the pivot axis to a position off-center from the pivot element to provide additional leverage for opening the blade. 
   The foregoing and other features of the invention will become more apparent from the following detailed description of several embodiments, which proceeds with reference to the accompanying figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a side view of a folding knife shown with the blade in the open position, according to one embodiment. 
       FIG. 1B  is a side view of the knife shown with the blade in the folded, or closed, position. 
       FIG. 1C  is a fragmentary side view of the knife shown with the blade in the open position and with the cover plate of the locking mechanism removed for clarity. 
       FIG. 1D  is a side view of the knife similar to  FIG. 1C  but showing the blade in the closed position. 
       FIG. 1E  is a cross-sectional view taken along line  1 E- 1 E of  FIG. 1A . 
       FIG. 1F  is a cross-sectional view taken along line  1 F- 1 F of  FIG. 1B . 
       FIG. 2  is a perspective view of the knife shown with the blade in the closed position. 
       FIG. 3  is a perspective view of the knife showing the locking mechanism in an unlocked position to allow the blade to be pivoted to the open position. 
       FIG. 4  is a perspective view of the knife showing the blade being pivoted to the open position. 
       FIG. 5  is a perspective view of the knife showing the blade in the fully extended, open position and the locking mechanism in an unlocked position. 
       FIG. 6  is a perspective view of the knife showing the blade in the fully extended, open position and the locking mechanism in a locked position to retain the blade in the open position. 
       FIG. 7  is a perspective view of the knife similar to that shown in  FIG. 6  but with the cover plate of the locking mechanism removed for illustrating the inside of the locking mechanism. 
       FIG. 8  is a perspective view of the knife similar to that shown in  FIG. 7  but showing the locking mechanism in the unlocked position to allow the blade to be closed. 
       FIG. 9  is a perspective, exploded view of the knife. 
   

   DETAILED DESCRIPTION 
   As used herein, the singular forms “a,” “an,” and “the” refer to one or more than one, unless the context clearly dictates otherwise. 
   As used herein, the term “includes” means “comprises.” For example, a device that includes or comprises A and B contains A and B but may optionally contain C or other components other than A and B. A device that includes or comprises A or B may contain A or B or A and B, and optionally one or more other components such as C. 
   Referring to the drawings, a folding knife  10 , according to one embodiment, comprises a blade  12  pivotably coupled to a handle  14  (also referred to as handle portion). The blade  12  is pivotable between a folded, or closed, position inside the handle  14  ( FIG. 2 ) and a fully extended, open position ( FIG. 5 ). As best shown in  FIG. 9 , the handle  14  in the illustrated embodiment comprises first and second inner liners  16  and  18 , respectively, and first and second side panels  20  and  22 , respectively, disposed outside of the liners  16 ,  18 . The knife  10  includes a locking mechanism  24  that is mounted for rotational movement with the blade and is operable to lock the blade  12  in the open position and optionally lock the blade  12  in the closed position, as described in detail below. The locking mechanism  24  in the illustrated embodiment is in the form of a first bolster of the knife. The knife  10  can also include a second bolster  26  positioned on the opposite side of the handle. 
   The blade  12  has a tang portion  28  disposed between the forward end portions of the liners  16 ,  18 , which can be separated by spacers  46 . The liners  16 ,  18  and the side panels  20 ,  22  can be held together by screws  78  extending through corresponding openings in the side panels and tightened into the spacers. In alternative embodiments, the handle  14  can have various other configurations. For example, each liner  16 ,  18  and corresponding side panel  20 ,  22  can be formed as a unitary member rather than separate components held together with fasteners. 
   A stop pin  84  or equivalent structure can be positioned between the liners  16 ,  18  to limit pivoting of the blade past the open and closed positions. As shown in  FIG. 1C , the stop pin  84  is positioned to contact the back edge of the tang portion  28  to limit pivoting movement of the blade  12  past the open position. When the blade is closed, the stop pin  84  may contact a lower edge of the tang portion to prevent pivoting of the blade past the closed position ( FIG. 1D ). 
   The liners  16 ,  18  can be formed with respective openings  30  and  32  for receiving a pivot element  34  for supporting the blade  12  and the locking mechanism. The pivot element  34  in the illustrated example defines a pivot axis extending through the tang portion  28  and the locking mechanism  24 . The pivot element  34  in particular embodiments includes a circular base  36  and an extension portion  38  having a non-circular cross-sectional profile that extends through a complimentary shaped opening  40  in the tang portion  28  and into an elongated slot, or opening,  56  in the locking mechanism  24 . In the illustrated embodiment, for example, the extension portion  38  of the pivot element has a relatively narrow, oblong cross-sectional profile with flat sides and the opening  40  in the tang portion  28  has a similar oblong shape. The slot  56  has straight sides defining a relatively narrow width that is slightly greater than the width of the extension portion  38 . By virtue of the shape of the extension portion  38 , the opening  40 , and the slot  56 , pivoting movement of the blade  12  causes corresponding rotation of the pivot element  34  and the locking mechanism  24  about the pivot axis. Thus, in the illustrated example, pivoting the blade  12  from the closed position to the open position, and vice versa, causes the locking mechanism  24  to rotate 180 degrees about the pivot axis. In alternative embodiments, various other shapes can be utilized for the extension portion  38 , the opening  40 , and the slot  56  to effect simultaneous movement of the blade, pivot element and the locking mechanism. For example, the extension portion  38  and the opening  40  can be a square, rectangle, triangle, ellipse, or various combinations thereof. 
   The second bolster  26  can include an inner plate  42  and an outer plate, or panel,  44 , which can be secured to the plate  42  by screws  49 . The plate  42  can be formed with a recess, or bore,  48  that receives the base  36  of the pivot element  34 . As best shown in  FIG. 1E , when the knife is assembled, the base  36  is disposed in the bore  48  and the extension portion  38  extends through openings  30 ,  32  in the liners  16 ,  18 , the opening  40  in the blade, and into the slot  56  in the locking mechanism  24 . 
   The locking mechanism  24  is configured to be slidable relative to the pivot element  34  in a direction perpendicular to the pivot axis to lock and unlock the blade when the blade is in the open position and optionally when the blade is in the closed position. In the illustrated example, the locking mechanism is configured to slide longitudinally of the blade (lengthwise of the blade) to lock and unlock the blade (as indicated by double-headed arrow  70  in  FIGS. 3 and 5 ). In certain embodiments, the locking mechanism  24  comprises a slidable inner plate  50  and an outer plate, or panel,  52 , which can be secured to the plate  50  by screws  54 . The slot  56  (which receives the extension portion  38  of the pivot element  34 ) is formed in the inner plate  50 , which can also be formed with first and second notches  58  and  60 , respectively, formed at opposite ends of the plate. The locking mechanism  24  can be secured to the pivot element  34  by screws  62  that extend through corresponding openings in a washer  64  and slot  56 , and are tightened into corresponding threaded openings  66  ( FIGS. 1E and 9 ) in the extension portion  38  of the pivot element  34 . The slot  56  is sized and shaped such that rotation of the pivot element  34  causes the locking mechanism  24  to rotate with the pivot element and the blade and allow the locking mechanism  24  to slide lengthwise of the blade relative to the pivot element to effect locking of the blade in the open or closed positions, as further described below. 
   The handle  14  is provided with a locking element, for example in the form of a locking pin  68  extending transversely from the first liner  16 , that is positioned to engage the notches  58 ,  60  in the slidable plate  50  of the locking mechanism. The locking mechanism  24  is operable to slide relative to the handle portion  14  and the blade  12  between a forward, unlocked position and a rearward, locked position when the blade  12  is in the open position and the closed position. As shown in  FIG. 7 , to lock the blade  12  in the open position, the locking mechanism  24  is slid to the rearmost, locked position with the locking pin  68  engaging the notch  58 , thereby resisting pivoting of the blade to the closed position. To unlock the blade, the locking mechanism  24  is slid to the forward-most position toward the tip of the blade to remove the plate  50  from engagement with the locking pin  68  ( FIG. 8 ). At this point, the blade  12  is free to pivot to the closed position. Once in the closed position, the blade  12  can be locked in place by sliding the locking mechanism rearwardly to cause the locking pin  68  to engage the notch  60  in the plate  50  ( FIG. 1D ). 
   As best shown in  FIG. 3 , the locking mechanism  24  in the illustrated configuration is formed with arcuate end portions  72 ,  74  that correspond to a similarly shaped end surface  76  of the first side panel  20 . The end portions  72 ,  74  desirably are curved so that the locking pin  68  does not interfere with the rotation of the locking mechanism  24  when the blade is opened or closed. In addition, as depicted in  FIGS. 2 and 6 , when the locking mechanism  24  is in the locked position, the locking mechanism abuts the side panel  20  and resembles a conventional bolster. In alternative embodiments, the locking mechanism  24  can have various other shapes or configurations and still effect locking of the blade in the manner described above. For example, the locking mechanism can be a disc or wheel that is connected to the pivot element  34  as previously described. 
   Another unique feature of the locking mechanism  24  in the illustrated embodiment is that it can be used to open or close the blade. For example, to open the blade from the closed position ( FIG. 2 ), the locking mechanism is first slid to the unlocked position ( FIG. 3 ), such as by applying pressure to the locking mechanism with the thumb. The locking mechanism  24  can then be rotated by applying thumb pressure in the direction of arrow  80  ( FIG. 3 ) to cause the blade  12  to pivot outwardly from the handle to the open position ( FIG. 5 ). The locking mechanism  24  can then be slid rearwardly to the locked position with the thumb to engage the locking pin  68  ( FIG. 6 ). The blade  12  can be pivoted closed by performing the foregoing steps in the reverse sequence. By virtue of its elongated shape in the illustrated embodiment, the locking mechanism  24  can function as a lever for opening and closing the blade. Further, when slid to the unlocked position, the locking mechanism  24  is positioned off-center from the pivot element  34  (the pivot element  34  is positioned closer to one end of the locking mechanism  24 , as best shown in  FIG. 8 ), which creates additional leverage to facilitate opening and closing of the blade. 
   In an alternative embodiment, the locking mechanism  24  can have a construction similar to that shown in the figures, but is not formed with a notch  60  to engage the locking pin  68  when the blade  12  is in the closed position. Thus, in this alternative embodiment, the locking mechanism  24  functions only to lock the blade when it is in the open position. The screws  62  can be tightened to provide sufficient frictional force to prevent the blade  12  from opening under its own weight, such as when holding or carrying the knife. 
   In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. I therefore claim as my invention all that comes within the scope and spirit of these claims.