Patent Publication Number: US-7222429-B2

Title: Locking folding knife and associated methods

Description:
RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/443,154 filed on Jan. 28, 2003, the entire disclosure of which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to the field of knives and, more particularly, to folding knives having locking mechanisms, and related methods. 
   BACKGROUND OF THE INVENTION 
   A folding knife may generally include a lock mechanism to keep the blade of the knife in a locked position when open. This may be helpful to reduce the possibility of the blade accidentally closing on a user&#39;s hand during use. For example, U.S. Pat. No. 5,826,340 to Hull discloses a traditional lock mechanism for a folding knife. 
   The knife includes a lock bar that is pivotally connected to a handle, adjacent the blade. The lock bar includes one lock member, and the blade includes a lock member receiving recess. The lock member includes a bottom wall, and two sidewalls that extend upwardly therefrom. The lock member receiving recess is defined by a bottom wall, and a pair of opposing sidewalls that extend upwardly therefrom. When the blade is in an opened position, the opposing sidewalls of the lock member matingly engage the respective opposing sidewalls of the lock member receiving recess. In other words, when the blade is in the opened position, respective surfaces of the lock member and the lock member receiving recess are in contact with one another. 
   This type of lock mechanism may, however, be prone to accidental unlocking by the user. Another problem that may occur with this type of lock mechanism is lock failure when a force is applied to a distal portion of the blade. 
   Another type of folding knife is illustrated in U.S. Pat. No. 5,615,484 to Pittman. This type of folding knife includes a lock mechanism having a stop pin and a slide member that engages the stop pin. When the blade is in the opened position, the stop pin contacts a notch formed in the end of the blade. The stop pin also contacts a sidewall of the slide member when the blade is in the opened position, and the slide member is in an engaged position. To return the blade to the closed position, the slide member is disengaged from contact with the stop pin, allowing the blade to be freely closed. This type of lock mechanism may also be disadvantageous because it may be prone to accidental unlocking by the user. 
   SUMMARY OF THE INVENTION 
   In view of the foregoing background, it is therefore an object of the present invention to provide a folding knife that more readily locks a blade in an opened position. 
   This and other objects, features, and advantages of the present invention are provided by a folding knife comprising a handle having a distal portion and a proximal portion. The proximal portion may have a recess formed therein. The folding knife may also include a blade rotatably connected to the handle, a lock bar pivotally connected to the handle, and a lock pin between the blade and the handle for readily locking the blade in an opened position. 
   More particularly, the blade may be rotatably connected to the distal portion of the handle and moveable between an opened position and a closed position. The blade may have at least one lock member receiving recess formed therein and may include an upper edge and a lower sharpened edge. 
   The lock bar may be pivotally connected to a medial portion of the handle and moveable between an engaged position and a disengaged position. The lock bar may comprise at least one lock member, a portion of which contacts a respective portion of the blade adjacent the lock member receiving recess to define a contact point between the lock member and the blade when the blade is in the opened position. The folding knife may further comprise a lock pin connected to the handle adjacent the lock member. 
   The lock member receiving recess may include a first and a second lock member receiving recess. The first lock member receiving recess may be defined by a bottom wall and first and second opposing sidewalls extending upwardly therefrom. The second lock member receiving recess is adjacent the first lock member receiving recess and may be defined by a bottom wall and a sidewall extending upwardly therefrom. 
   The lock member may comprise a first lock member and a second lock member. The first lock member may be defined by a bottom wall and first and second sidewalls extending upwardly therefrom. The second lock member is adjacent the first lock member and may be defined by a bottom wall and a sidewall extending upwardly therefrom. 
   The bottom wall and sidewall of the second lock member may be spaced apart from the bottom wall and sidewall of the second lock member receiving recess when the lock bar is in the engaged position. 
   The lock pin may be connected to the handle adjacent the first and second lock members so that when the blade is in the opened position, the lock pin contacts the second sidewall of the first lock member, and the bottom wall of the second lock member receiving recess. Further, the sidewall of the second lock member receiving recess may be spaced apart from the lock pin and from the sidewall of the second lock member when the blade is in the opened position. Accordingly, the configuration of the lock member, the lock member receiving recesses, and the lock pin advantageously provides a more reliable lock when the blade is in the opened position, and when the lock bar is in the engaged position. 
   The folding knife may further comprise a lock bar spring member connected to the handle to engage a portion of the lock bar. The lock bar spring member advantageously provides resistance to the movement of the lock bar to reduce the risk of a user accidentally moving the lock bar to the disengaged position. 
   The folding knife may also comprise a blade connecting member connected to the handle. The blade may comprise a blade connecting member passageway for receiving the blade connecting member to thereby rotatably connect the blade to the handle. The folding knife may further comprise a lock bar connecting member connected to the handle. The lock bar may have a lock bar connecting member passageway formed therein for receiving the lock bar connecting member to thereby pivotally connect the lock bar to the handle. 
   The first lock member receiving recess may be U-shaped, and the second lock member receiving recess may be L-shaped. The sharpened lower edge may be adjacent a lower edge of the lock bar when the blade is in the closed position. This advantageously provides a barrier to the sharpened lower edge of the blade when in the closed position. 
   A method aspect of the present invention is for locking a folding knife in an opened position. The method may comprise moving the blade to the opened position, and moving the lock bar to the engaged position so that a portion of the lock member contacts a respective portion of the blade adjacent the lock member recess to thereby define a contact point between the lock member and the blade when the blade is in the opened position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of a folding knife according to the present invention. 
       FIG. 2  is an enlarged partial side elevational view of the folding knife shown in  FIG. 1 . 
       FIG. 3  is a side elevational view of the folding knife shown in  FIG. 1  with the blade being moved between an opened and a closed position. 
       FIGS. 4-6  are partial perspective views of another embodiment of the folding knife according to the present invention. 
       FIG. 7  is an exploded partial perspective view of the embodiment of the folding knife as shown in  FIGS. 4-6 . 
       FIG. 8  is a partial perspective view of yet another embodiment of the folding knife according to the present invention. 
       FIG. 9  is a side elevational view of the embodiment of the folding knife shown in  FIG. 8 . 
       FIG. 10  is a partial side elevational view of still another embodiment of the folding knife according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime, double prime, and triple prime notations are used to indicate similar elements in alternate embodiments. 
   Referring initially to  FIGS. 1-3 , a first embodiment of a folding knife  20  according to the present invention is now described. In  FIGS. 1 and 2 , the folding knife  20  is illustrated in an opened position. In  FIG. 3 , the folding knife  20  is illustrated as being moved between an opened position and a closed position. More specifically, the folding knife  20  includes a front cover and a rear cover, but is illustrated in  FIGS. 1-3  without the front cover for clarity. 
   The folding knife  20  illustratively includes a handle  24 , and a blade  26  rotatably connected to the handle. The blade  26  is moveable between an opened position and a closed position, and includes a proximal end portion  50  and a distal end portion  51 . 
   The folding knife  20  also includes a blade connecting member  28  connected to the handle  24 . The blade  26  also has a blade connecting member passageway formed therein. The blade connecting member passageway may receive the blade connecting member  28  to rotatably connect the blade  26  to the handle  24 . The blade connecting member  28  may be a blade connecting pin, for example, or any other type of connector that rotatably connects the blade  26  to the handle  24 , as understood by those skilled in the art. The blade connecting member  28  acts as an axis of rotation about which the blade  26  rotates when being moved from the opened position to the closed position. 
   The blade  26  illustratively includes a lock member receiving recess, which includes a first lock member receiving recess  53  formed in the proximal end portion  50  thereof. The first lock member receiving recess  53  is defined by a bottom wall  54 , and a first and second opposing sidewalls  56 ,  55  extending upwardly therefrom. The lock member receiving recess may also illustratively includes a second lock member receiving recess  57 . The second lock member receiving recess  57  is adjacent the first lock member receiving recess  53  and defined by a bottom wall  58  and a sidewall  59  extending upwardly therefrom. The first lock member receiving recess  53  may be a U-shaped recess, and the second lock member receiving recess  57  may be an L-shaped recess, for example. 
   The folding knife  20  also includes a lock bar  30  pivotally connected to the handle  24 . More specifically, the lock bar  30  is moveable between an engaged position and a disengaged position. The folding knife  20  includes a lock bar connecting member  22  connected to the handle  24 . Further, the lock bar  30  has a lock bar connecting member passageway formed therein. The lock bar connecting member passageway receives the lock bar connecting member  22  to pivotally connect the lock bar  30  to the handle  24 . The lock bar connecting member  22  may be provided by a lock bar connecting pin, for example, or another type of connecting member suitable for pivotally connecting the lock bar  30  to the handle  24 . 
   The lock bar  30  is elongate and has a proximal end portion  32  and a distal end portion  34 . The lock bar  30  also includes a lock member  25  along the distal end portion  34  thereof. The lock member  25  includes a first lock member  40  defined by a bottom wall  41  and first and second sidewalls  43 ,  42  extending upwardly therefrom. More specifically, the first lock member  40  extends downwardly from a lower edge of the lock bar  30 . 
   The lock member  25  also includes a second lock member  46  adjacent the first lock member  40 . The second lock member  46  is defined by a bottom wall  47  and a sidewall  48  extending upwardly therefrom. The bottom wall  47  of the second lock member  46  illustratively contacts the second sidewall  42  of the first lock member  40  to form an L-shape. 
   As illustrated in  FIGS. 1 and 2 , the lock bar  30  is preferably in an engaged position when the blade  26  is in the opened position. As illustrated in  FIG. 3 , the lock bar  30  is moved from the engaged position to the disengaged position to move the blade  26  from the opened position to the closed position. When the blade  26  is in the opened position, a portion of the first sidewall  43  of the first lock member  40  contacts a portion of the first sidewall  56  of the first lock member recess  53  to define a contact point  88  between the lock bar  30  and the blade  26 . 
   The folding knife  20  further illustratively comprises a lock pin  70  connected to the handle  24  adjacent the first and second lock members  40 ,  46  so that when the blade  26  is in the opened position, the lock pin contacts the second sidewall  42  of the first lock member  40  and the bottom wall  58  of the second lock member receiving recess  57 . Accordingly, the second lock member  46  may be a lock pin cover member, for example. 
   As perhaps best illustrated in  FIGS. 1 and 2 , the bottom wall  47  and sidewall  48  of the second lock member  46  are spaced apart from the bottom wall  58  and sidewall  59  of the second lock member receiving recess  57  when the lock bar  30  is in the engaged position. The sidewall  59  of the second lock member receiving recess  57  is also spaced apart from the lock pin  70  when the blade  26  is in the opened position. 
   As further illustrated in  FIGS. 1 and 2 , when the blade  26  is in the opened position, the lock pin  70  illustratively contacts the bottom wall  58  of the second lock member receiving recess  57 , and also contacts the second sidewall  42  of the first lock member  40 . Further, the sidewall  59  of the second lock member receiving recess  57  is spaced apart from the sidewall  48  of the second lock member  46  when the blade  26  is in the opened position. Accordingly, when the blade  26  is in the opened position, and the lock bar  30  is in the engaged position, the lock pin  70  contacts portions of the blade and portions of the lock bar to advantageously provide additional lock stability to the blade. 
   This configuration further advantageously reduces the risk of the blade  26  inadvertently being moved to the closed position due to lock failure. The contact of the lock pin  70  with the second sidewall  42  of the first lock member  40  advantageously causes the first lock member to be wedged between the lock pin and the first sidewall  56  of the first lock member receiving recess  53  to thereby enhance the strength of the lock member  25 . In other words, the lock pin  70  enhances the lock strength associated with contact between the lock bar  30  and the blade  26  when the blade is in the opened position, and the lock bar is in the engaged position. 
   Those skilled in the art will appreciate that the second lock member  46  is not necessary for the blade  26  to be locked in place when in the open position. More specifically, the folding knife  20  may be readily used to lock the blade  26  in the open position without the use of the second lock member  46 . This is possible because of the configuration of the lock pin  70 . In other words, if a force is applied to the distal end  51  of the blade  26  while the lock bar  30  is in the engaged position, the second sidewall  42  of the first lock member  40  would contact the lock pin  70 , and cause the first lock member to be wedged in the first lock member receiving recess  53 , thereby enhancing the strength of the lock member  25 . More specifically, the lock strength associated with contact between the lock bar  30  and the blade  26  may advantageously be greatly enhanced. 
   The blade  26  illustratively comprises an upper edge  62 , and a lower edge  60 . The lower edge  60  may be a sharpened lower edge. The upper edge  62  and the lower edge  60  of the blade  26  extend from the proximal end portion  50  of the blade initially spaced from one another, to the distal end portion  51  of the blade, where the upper edge and the lower edge of the blade meet to form a tip  64 . The upper edge  62  of the blade  26  may include portions that are sharpened. 
   In other embodiments, however, the upper edge  62  of the blade  26  may remain completely unsharpened, or completely sharpened, as understood by those skilled in the art. The upper edge  62  of the blade  26  may also be serrated, for example, or have any other type of finish, as understood by those skilled in the art. The sharpened lower edge  60  of the blade  26  is illustratively adjacent a lower edge of the lock bar  30  when the blade is in the closed position. 
   A recess  36  may be formed in a proximal end portion  32  of the handle  24 . The recess  36  allows a user to access the proximal end  32  of the lock bar  30  to move the lock bar between the engaged and the disengaged positions. 
   The folding knife  20  may also comprise a lock bar spring member  80  connected to the handle  24  to engage a portion of the lock bar  30 . When a user depresses the lock bar  30  along the recess  36  in the handle  24 , the spring member  80  provides a predetermined amount of resistance. Further, upon releasing the lock bar  30  adjacent the recess  36  in the handle  24 , the resistance provided by the spring member  80  returns the lock bar to the engaged position. It should be noted that the lock bar  30  is generally in the engaged position, and is moved to the disengaged position when moving the blade  26  between the opened and closed positions. 
   The blade  26 , handle  24 , lock bar  30 , spring member  80 , lock bar connecting member  22 , blade connecting member  28 , and lock pin  70  may all be made of high strength, light weight material, such as stainless steel, for example, or any other type of material having similar high strength properties, as understood by those skilled in the art. 
   Referring now additionally to  FIGS. 4-7 , a second embodiment of the folding knife  20 ′ is now described. In the second embodiment of the folding knife  20 ′, the lock pin  70 ′ illustratively includes a first end  71 ′ and a second end  72 ′. The first end  71 ′ of the lock pin  70 ′ may be tapered. The second end  72 ′ of the lock pin  70 ′, which opposes the first end  71 ′ of the lock pin, may be threaded. 
   Referring now more specifically to the exploded view of the folding knife  20 ′ illustrated in  FIG. 7 , the second embodiment of the invention is now described in greater detail. The handle  24 ′ of the folding knife  20 ′ may further include a lock pin receiving passageway  74 ′ formed therein. The lock pin receiving passageway  74 ′ may also be threaded to threadingly receive the second end  72 ′ of the lock pin  70 ′. More specifically, the tapered end of the lock pin  70 ′ may advantageously be readily inserted through the lock pin receiving passageway  74 ′ to a point where the second end  72 ′ of the lock pin engages the threaded portion of the lock pin receiving passageway. Accordingly, a user may turn the lock pin  70 ′ in a predetermined direction to secure the lock pin in the lock pin receiving passageway  74 ′. 
   The tapered and threaded lock pin  70 ′ advantageously allows a user to adjust the tension of the lock strength to be compensated for ware, when needed. Further, the tapered and threaded lock pin  70 ′ advantageously allows a user to adjust positioning within the lock pin receiving recess  74 ′. The other elements of the second embodiment of the folding knife  20 ′ are similar to those of the first embodiment, are labelled with prime notation, and require no further discussion herein. 
   Referring now additionally to  FIGS. 8 and 9 , a third embodiment of the folding knife  20 ″ is now described in greater detail. The third embodiment of the folding knife  20 ″ illustratively includes a lock bridge  90 ″. The blade  26 ″ of the third embodiment of the folding knife  20 ″ has a first lock member receiving recess  53 ″ and a second lock member receiving recess  57 ″ formed therein. 
   The lock bar  30 ″ of the second embodiment of the folding knife  20 ″ includes a lock member  40 ″. The lock bridge  90 ″ may have an H-shape so that a medial portion of a first side  92 ″ of the lock bridge may contact the sidewall  42 ″ of the lock member  40 ″, and so that a medial portion of the second side  93 ″ of the lock bridge is adjacent to the sidewall  59 ″ of the second lock member receiving recess  57 ″ when the blade  26 ″ is in the opened position. More specifically, the medial portion of the second side  93 ″ of the lock bridge  90 ″ is spaced apart from the sidewall  59 ″ of the second lock member receiving recess  57 ″. 
   The lock bridge  90 ″ may have a trapezoidal shape, but may also have another shape suitable for contacting portions of the lock bar  30 ″ when the lock bar is in the engaged position, as understood by those skilled in the art. The lock bridge  90 ″ further illustratively includes a set screw  91 ″ and a set screw receiving passageway formed therein. Both the set screw  91 ″ and the set screw receiving passageway are preferably threaded to thereby engage one another when turning the set screw to position the blade  26 ″ to a desired height. 
   A bottom portion of the set screw  91 ″ may contact the bottom wall  58 ″ of the second lock member receiving recess  57 ″ when the blade  26 ″ is in the opened position. The height of the blade  26 ″ may advantageously be adjusted by a user using the set screw  91 ″. The lock bridge  90 ″ eliminates the need for the lock pin  70 ,  70 ′ disclosed in the first and second embodiments of the folding knife  20 ,  20 ′. 
   The lock bridge  90 ″ advantageously enhances the lock strength of the folding knife  20 ″ associated with contact between the lock bar  30 ″, the set screw  91 ″, and the blade  26 ″ when the blade is in the opened position and the lock bar is in the engaged position. The other elements of the third embodiment of the folding knife  20 ″ are similar to those of the first embodiment, are labelled with double prime notation, and require no further discussion herein. 
   Turning now additionally to  FIG. 10 , a fourth embodiment of the folding knife  20 ′″ is now described. The fourth embodiment of the folding knife  20 ′″ illustratively includes a lock pin  70 ′″, and a lock bar  30 ′″ including a first lock member  40 ′″ and a second lock member  46 ′″. The blade  26 ′″ illustratively includes a first lock member receiving recess  53 ′″ defined by a bottom wall  54 ′″, and first and second opposing sidewalls  55 ′″,  56 ′″, extending upwardly therefrom. 
   The fourth embodiment of the folding knife  20 ′″ further illustratively includes a blade set screw  100 ′″ for setting a desired height of the blade  26 ′″. The blade  26 ′″ further has a blade set screw passageway formed in the bottom wall  54 ′″ of the first lock member receiving recess  53 ′″ for receiving the blade set screw  100 ′″. The blade set screw  100 ′″ and the blade set screw receiving recess may be threaded so that the height of the blade set screw may be adjusted by a user, thereby adjusting the height of the blade  26 ′″. The other aspects of the fourth embodiment of the folding knife  20 ′″ are similar to those of the first embodiment of the folding knife  20 , are labelled with triple prime notation, and require no further discussion herein. 
   A method aspect of the present invention is for locking a folding knife  20  in an opened position. The method may comprise moving the blade  26  to the opened position, and moving the lock bar  30  to the engaged position so that a portion of the lock member  25  contacts a respective portion of the blade adjacent the lock member recess  53  to thereby define a contact point  88  between the lock member and the blade when the blade is in the opened position. 
   Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.