Patent Publication Number: US-8966769-B1

Title: Folding knife with bolt locking assembly

Description:
FIELD OF THE INVENTION 
     The present invention relates to knives and more particularly to safety mechanisms on folding knives. 
     BACKGROUND OF THE INVENTION 
     Knives are useful, everyday tools. Folding knives are knives with blades that pivot between an open position in which the blade is deployed for use and a closed position in which the blade is stored for non-use. Users generally desire that the blade remain in the open position when the knife is being used and that the blade remain in the closed position when the knife is not being used. 
     Various locking systems have been developed in the past to lock the blade in position. However, many of these locking arrangements are complex or subject to accidental release. Many are not aesthetically pleasing and can interfere with the use or storage of the knife. An improved safety mechanism for a folding knife is needed. 
     SUMMARY OF THE INVENTION 
     According to the principle of the invention, a folding knife includes a bolt locking assembly for locking and unlocking a knife blade having a tang. The bolt locking assembly includes first and second bolts carried for reciprocation in the knife. When the blade is open and the bolt locking assembly is in a locked configuration, lugs on the first and second bolts are in contact with tang, preventing pivotal movement of the blade. When the blade is closed and the bolt locking assembly is in the locked configuration, at least one of the lugs on the first and second bolts is in contact with the tang, preventing pivotal movement of the blade. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings: 
         FIG. 1  is an exploded perspective view of an embodiment of a folding knife according to the principle of the invention, including a blade, a handle assembly, a grip locking assembly, bolt locking assembly, and locking member for locking the blade, and a cap assembly for preventing depression of the bolt locking assembly; 
         FIGS. 2A and 2B  are section views taken along the line  2 - 2  in  FIG. 1 , showing the grip locking assembly of  FIG. 1  in an unlocked configuration and a locked configuration, respectively; 
         FIGS. 3A and 3B  are section views taken along the line  3 - 3  of  FIGS. 2A and 2B , showing the blade in an open position and the grip locking assembly of  FIG. 1  arranged in the unlocked and locked configurations, respectively; 
         FIG. 4  is a view similar to that of  FIG. 1 , showing an alternate embodiment of a folding knife having a grip locking assembly carried in the handle assembly; 
         FIGS. 5A and 5B  are section views taken along the line  5 - 5  in  FIG. 4 , showing the grip locking assembly of  FIG. 4  in an unlocked configuration and a locked configuration; 
         FIG. 6  is a view similar to that of  FIG. 1 , showing an alternate embodiment of a folding knife having a grip locking assembly; 
         FIGS. 7A and 7B  are top plan views of the knife of  FIG. 1  showing the locking member in a raised position and a collapsed position, respectively; 
         FIG. 8  illustrates a right-half portion of the view in  FIG. 1 ; 
         FIG. 9  is an isolated, exploded perspective view of the blade and the bolt locking assembly of  FIG. 1 ; 
         FIG. 10  is an isolated side elevation view of the blade and the bolt locking assembly of  FIG. 1  in an open position of the blade; 
         FIGS. 11 and 12  are isolated, top plan views of the blade and bolt locking assembly of  FIG. 10  in a locked configuration and an unlocked configuration, respectively, of the bolt locking assembly; 
         FIG. 13  is an isolated side elevation view of the blade and the bolt locking assembly of  FIG. 1  in a closed position of the blade; 
         FIG. 14  is an isolated top plan view of the blade and bolt locking assembly of  FIG. 13  in a locked configuration of the bolt locking assembly; 
         FIG. 15  is an isolated, exploded perspective view of the blade of  FIG. 1  and an alternate embodiment of a bolt locking assembly; 
         FIG. 16  is an isolated, exploded perspective view of the blade of  FIG. 1  and an alternate embodiment of a bolt locking assembly; 
         FIG. 17  is a section view of the bolt locking assembly of  FIG. 16  taken along the line  17 - 17  in  FIG. 16 ; 
         FIG. 18  is an exploded perspective view of the blade and handle assembly of  FIG. 1  and an alternate embodiment of a bolt locking assembly; 
         FIG. 19  is an isolated, exploded view of the blade and bolt locking assembly of  FIG. 18 ; 
         FIG. 20  is an isolated, exploded perspective view of the blade of  FIG. 1  and an alternate embodiment of a bolt locking assembly; 
         FIG. 21  is a section view of the bolt locking assembly of  FIG. 20  taken along the line  21 - 21  in  FIG. 20 ; 
         FIG. 22  is an isolated, exploded perspective view of the cap assembly of  FIG. 1 ; 
         FIGS. 23A and 23B  are isolated, perspective views of the cap assembly and handle assembly of  FIG. 1  showing the cap assembly in a locked position and an operative position, respectively, over the bolt locking assembly; 
         FIGS. 24A-24C  are section views taken along the line  24 - 24  in  FIG. 23A , showing a sequence of steps of moving the cap assembly from the locked position to the operative position and depressing the bolt locking assembly; 
         FIG. 25  is an isolated, exploded perspective view of an alternate embodiment of a cap assembly; and 
         FIGS. 26A and 26B  are isolated, perspective views of the cap assembly of  FIG. 25  and the handle assembly of  FIG. 1  showing the cap assembly in a locked position and an operative position, respectively, with respect to the bolt locking assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Reference is now made to the drawings, in which the same reference characters are used throughout the different figures to designate the same components.  FIG. 1  is an exploded view of an embodiment of a folding knife  50  constructed and arranged according to the principle of the invention. The knife  50  has safety features for preventing the accidental opening and closing of the knife  50  during use and storage of the knife  50 . The knife  50  includes a blade  51  mounted for pivotal movement to a handle assembly  52  formed of opposed left and right handle portions  53  and  54 . The left and right handles portions  53  and  54  are symmetric and, as such, reference will be made to the right handle portion  54 , and the constituent parts thereof, with the understanding that the discussion applies equally to the left handle portion  53 , and the constituent parts thereof which will be identified with a prime (“′”) to distinguish those parts from the parts of the right handle portion  54 . In some instances, reference will be made to the constituent parts of the left handle portion  53  for clarity of illustration, and it should be understood that the discussion applies equally to the right handle portion  54 . Except as otherwise identified herein, all parts of the knife  50  are constructed from hard, durable, and rigid materials, such as metal, hardened metal, wood, plastic, or ceramic materials. 
     The right handle portion  54  includes a handle  55  and a liner  56 . The handle  55  has an outer surface  55   a  and an opposed inner surface  55   b , and a front  55   c  and an opposed butt  55   d . The liner  56  has an outer surface  56   a  and an opposed inner surface  56   b , and a front  56   c  and an opposed butt  56   d . Likewise, the left handle portion  53  includes a handle  55 ′ and a liner  56 ′. The handle  55 ′ has an outer surface  55   a ′ and an opposed inner surface  55   b ′, a front  55   c ′ and an opposed butt  55   d ′, and a peripheral edge  52   a . The liner  56 ′ has an outer surface  56   a ′ and an opposed inner surface  56   b ′, and a front  56   c ′ and an opposed butt  56   d′.    
     With continuing reference to  FIG. 1 , the handle assembly  52  also includes an elongate spacer  57  having a front  57   a , an opposed arcuate butt  57   b , and opposed left and right surfaces  57   c  and  57   d . The spacer  57  has a thickness A between the left and right surfaces  57   c  and  57   d . The spacer  57  is also formed with an arcuate notch  57   e  proximate to the front  57   a  extending through the spacer  57  between the left and right surfaces  57   c  and  57   d.    
     The handle assembly  52  is fastened together with fasteners  60  secured between the left and right handle portions  53  and  54 . The fasteners  60  extend from the handle  55 ′, through the liner  56 ′, the spacer  57 , the liner  56 , and the handle  55 . Secured in this manner, the inner surface  55   b  of the handle  55  is in contact with the outer surface  56   a  of the liner  56 , the inner surface  56   b  of the liner  56  is in contact with the right surface  57   d  of the spacer  57 , the left surface  57   c  of the spacer  57  is in contact with the inner surface  56   b ′ of the liner  56 ′, and the outer surface  56   a ′ of the liner  56 ′ is in contact with the inner surface  55   b ′ of the handle  55 ′. The inner surfaces  56   b  and  56   b ′ of the liners  56  and  56 ′, respectively, cooperate with the spacer  57  to define a channel  61  in the handle assembly  52  between the left and right handle portions  53  and  54  for receiving the blade  51  in a storage or closed position of the blade  51 . The peripheral edge  52   a  on the handle  55 ′ has a downward edge  52   a , referenced in  FIG. 1  on the liner  56 , about which a user&#39;s fingers are wrapped when the knife  50  is being used, and an opposed back edge  52   c . The downward edge  52   b  is directed downward when the knife  50  is gripped in a forward gripping arrangement and being used. In the forward gripping arrangement, the user&#39;s hand is wrapped around the handle assembly  52 , with the palm against the back edge  52   c  and the fingers around the downward edge  52   b  of the knife  50 . 
     The blade  51  has a tang  62  mounted to the handle assembly  52 , an opposed tip or point  63 , and an edge  64  and opposed spine  65 . The blade  51  has a thickness B as indicated in  FIG. 1  which is just less than the thickness A of the spacer  57  so that the blade  51  may be stored within the channel  61  in the spacer  57 . The tang  62  is mounted for rotation to the handle assembly  52  on a pin or rivet  60  proximate to the fronts  55   c ,  56   c ,  55   c ′,  56   c ′, and  57   a  of the handle  55 , the liner  56 , the handle  55 ′, the liner  56 ′, and the spacer  57 , respectively, for pivotal movement along double-arrowed line I about an axis C, indicated in dotted line in  FIG. 1 , between an extended, deployed, or open position in which the point  63  of the blade  51  is away from the handle assembly  52  opposite the butt  57   b  of the spacer  57 , and a retracted, stored, or closed position in which the blade  51  is within the channel  61  in the handle assembly  52  and the point  63  is proximate to the butt  57   b  of the spacer  57 . In the open position of the blade  51 , the edge  64  of the blade  51  is collinear with the downward edge  52   b  of the handle assembly  52 . 
     The tang  62  has an arcuate outer edge  62   a  defined between opposed left and right faces  62   b  and  62   c . The left and right faces  62   b  and  62   c  are flat, parallel to each other, and perpendicular to the axis C of pivotal movement of the blade  51 . The outer edge  62   a  is contoured around the tang  62  and formed with first, second, and third notches  116 ,  117 , and  118 . The left and right faces  62   b  and  62   c  are formed with detents  73  and  74 , respectively, which are generally hemispherical depressions extending into the tang  62  from the left and right surfaces  62   b  and  62   c.    
     The knife  50  has structure to lock the blade  51  when the knife  50  is gripped in the forward gripping arrangement and used. Two grip locking assemblies  75  and  76  are carried by the knife  50  on the handle assembly  52  and are operatively coupled to the blade  51 . The grip locking assemblies  75  and  76  are identical in every respect to each other, other than location and as otherwise noted herein, and as such, reference will be made only with respect to the grip locking assembly  76  with the understanding that the discussion applies equally to the grip locking assembly  75 , and the constituent parts of the grip locking assembly  75  will be identified with a prime (“′”) to distinguish those parts from those of the grip locking assembly  76 . 
     The grip locking assembly  76  includes a cam  80 , an axle  81  on which the cam  80  is mounted for rotation, a spring  82  exerting a bias on the cam  80  about the axle  81 , a depression  83  in the liner  56 , a bore  84  through the liner  56  along an axis D, a ball  85  carried in the bore  84 , and the detent  74 . The depression  83  is a recess extending into the liner  56  from the outer surface  56   a  of the liner  56  at the downward edge  52   b  of the handle assembly  52  and is sized and shaped to receive the cam  80 . The axle  81  is a bolt having an enlarged head fit within a socket  86  on the outer surface  55   a  of the handle  55 , a shank extending into the handle assembly  52  and encircled by a hole  80   a  through the cam  80 , and a threaded end secured to a threaded hole  83   a  in the depression  83 . The cam  80  is mounted with a frictional-bearing fit on the shank of the axle  81  for pivotal movement of the cam  80  with respect to the depression  83  about an axis E shown in  FIG. 1  between a raised, or released, position of the cam  80  and a lowered, or gripped, position of the cam  80 . Axis D is parallel to axes C and E and is normal to a plane defined by the pivotal movement of the cam  80 . 
     The spring  82  is a torsional spring fitted on the axle  81  which biases the cam  80  into the raised position. As seen in  FIG. 2A , which is a sectional view taken along the line  2 - 2  in  FIG. 1 , in the raised position of the cam  80 , the cam  80  projects above the downward edge  52   b  of the peripheral edge  52   a  of the handle assembly  52 . The ball  85 , which is carried in the bore  84  when the cam  80  is in the raised position, is free to move within the bore  84  and does not interact with the cam  80  which is away from the bore  84 .  FIG. 3A  illustrates a section view taken along the line  3 - 3  in  FIG. 2A , in which the cam  80  is not visible because the cam  80  is in the raised position partially out of the depression  83 , and the ball  85  is carried in the bore  84  proximate to the inner surface  55   b  of the handle  55 , out of the detent  74 . With the ball  85  located out of the detent  74 , the tang  62  of the blade  51  is free to pivot between the open and closed positions of the blade  51  without interference with the ball  85 . With both cams  80  and  80 ′ moved into the raised positions thereof projecting beyond the downward edge  52   b , and the balls  85  and  85 ′ within the bores  84  and  84 ′, the grip locking assemblies  75  and  76  each define an unlocked configuration in which the blade  51  is free to pivot. 
     As seen in  FIG. 2B , which is a sectional view also taken along the line  2 - 2  in  FIG. 1 , in the lowered position of the cam  80 , the cam  80  is recessed within the depression  83 , so that the cam  80  is one of flush with and just below the downward edge  52   b  of the peripheral edge  52   a  of the handle assembly  52 .  FIG. 3B  illustrates a section view taken along the line  3 - 3  in  FIG. 2B , in which the ball  85 , carried in the bore  84 , encounters the cam  80 . The cam  80  in the depression  83  interacts with and urges the ball  85  along axis D toward the tang  62  of the blade  51 , moving the ball  85  in translational movement through the bore  84  into the detent  74 . The detent  74  is sized and shaped to receive approximately a hemispherical portion of the ball  85 , so that with the ball  85  received in the detent  74 , a portion of the ball  85  remains outside of the detent  74  in the bore  84 , and the ball  85  is located in an interference position juxtaposed with the tang  62 . The ball  85  is maintained in this position, prevented from moving laterally along axis D with respect to the tang  62  by the detent  74  on one side of the ball  85  and the cam  80  on the other side of the ball  85 , so that the ball  85  defines an impedance to pivotal movement of the blade  51  that is fixed within the handle assembly  52 . With the ball  85  against the tang  62 , the blade  51  is prevented from moving between the open and closed positions. With both cams  80  and  80 ′ moved into the lowered positions thereof into the depressions  83  and  83 ′, and the balls  85  and  85 ′ located within the detents  74  and  73  in juxtaposition with the tang  62  of the blade  51 , the grip locking assemblies  75  and  76  each define a locked configuration in which the blade  51  is prevented from pivotal movement. 
     With reference back to  FIG. 1 , the spring  82  biases the cam  80  into the raised position. When a user desires to use the knife  50 , the user grips, as by hand, the knife  50  in the forward gripping arrangement in which the user&#39;s hand is wrapped around the handle assembly  52  and the fingers are around the downward edge  52   b  of the knife  50 , so that the fingers are against the cams  80  and  80 ′. By closing or tightening the user&#39;s grip on the knife  50  in the forward gripping arrangement, the user&#39;s fingers depress the cams  80  and  80 ′ into the lowered positions thereof, urging the balls  85  and  85 ′ into the detents  74  and  73  so that the grip locking assemblies  75  and  76  are in the locked configuration while the user grips the knife  50 . The knife  50  is then used while the user maintains the forward gripping arrangement on the knife  50 , thus maintaining the cams  80  and  80 ′ in the lowered positions and the grip locking assemblies  75  and  76  in the locked configurations during operation. 
     Briefly, an alternate embodiment is shown in  FIGS. 4 ,  5 A, and  5 B as knife  50 ′.  FIGS. 5A and 5B  are section views taken along line  5 - 5  in  FIG. 4 . The knife  50 ′ includes features identical to that of the knife  50 , as indicated with common reference numbers. However, in knife  50 ′, the depressions  83  and  83 ′ are carried on the right and left handle portions  54  and  53 , respectively, rather than the liners  56  and  56 ′. One having ordinary skill in the art will understand that operation of the knife  50 ′ is the same as operation of the knife  50 . 
     Another embodiment is shown in  FIG. 6  as knife  50 ″. The knife  50 ″ includes features identical to that of the knife  50 , as indicated with common reference numbers. However, the knife  50 ″ includes alternate grip locking assemblies  90  and  91 , which are different from the grip locking assemblies  75  and  76 . The grip locking assemblies  90  and  91  are identical in every respect to each other, other than location and as otherwise noted herein, and as such, reference will be made only with respect to the grip locking assembly  91  with the understanding that the discussion applies equally to the grip locking assembly  90 , and the constituent parts of the grip locking assembly  90  will be identified with a prime (“′”) to distinguish those parts from those of the grip locking assembly  91 . 
     The grip locking assembly  91  includes a cam  92 , an axle  93  on which the cam  92  is mounted for rotation, a depression  94  in the handle  55 , a bore  95  extending along an axis G through the liner  56 , a ball  96  carried in the bore  95 , a rod  97  carried in a channel  98  extending between the depression  94  and the bore  95 , and a spring  99  exerting a bias on the rod  97  toward the cam  92 . Axis F is parallel to axis C and normal to a plane defined by the pivotal movement of the cam  92 . 
     The depression  94  is a recess extending into the handle  55  from the inner surface  55   b  of the handle  55  and is sized and shaped to receive the cam  92 . The axle  93  is a bolt having an enlarged head fit within a socket on the outer surface  55   a  of the handle  55 , a shank extending into the handle assembly  52 , and a threaded end secured to a threaded hole  94   a  in the liner  56  proximate to the depression  94 . The cam  92  is mounted with a frictional-bearing fit on the shank of the axle  93  for pivotal movement of the cam  92  with respect to the depression  94  about an axis F shown in  FIG. 6  between a raised, or released, position of the cam  92  and a lowered, or gripped, position of the cam  92 . Axis F is parallel to axis G. 
     The channel  98  is formed in the handle  55  and includes a front  98   a  located proximate to the front  55   c  of the handle  55  and an opposed rear  98   b  located at the depression  94 . A shoulder  98   c  is formed at the rear  98   b . The rod  97  is fit within the channel  98  and includes a tapered head  97   a  and an opposed angled foot  97   b . The head  97   a  is located proximate to the front  98   a  of the channel  98 , and the foot  97   b  is proximate to the rear  98   b  in juxtaposition with the cam  92 . 
     The rod  97  reciprocates in a direction generally indicated by double-arrowed line H within the channel  98  in response to pivotal movement of the cam  92 . The rod  97  moves into an advanced position along the handle  55  toward the front  55   c  in response to movement of the cam  92  into the lowered position, and the rod  97  moves into a retracted position along the handle away from the front  55   c  in response to movement of the cam  92  into the raised position. The spring  99  is a linear spring and is spaced between the shoulder  98   c  and the foot  97   b  to urge the rod  97  into the retracted position and the cam  92  into the raised position. When the rod  97  is in the retracted position, the tapered head  97   a  of the rod  97  is away from the bore  95  and from the ball  96 , and the ball  96  is free to move outside of the detent  74  within the bore  95 . With the ball  96  free to move out of the detent  74 , the tang  62  of the blade  51  is free to pivot between the open and closed positions of the blade  51  without interference with the ball  96 . With both cams  92  and  92 ′ moved into the raised positions thereof projecting beyond the downward edge  52   b  of the peripheral edge  52   a , and the balls  96  and  96 ′ within the bores  95  and  95 ′, the grip locking assemblies  90  and  91  each define an unlocked configuration in which the blade  51  is free to pivot. 
     When the cam  92  is lowered, as by taking up the knife in a forward gripping arrangement as discussed above, the rod  97  is moved into the advanced position, and the tapered head  97   a  of the rod  97  is proximate to the bore  95 , interacting with and urging the ball  96  to translate along axis G toward the tang  62  of the blade  51  into the detent  74 . The detent  74  is sized and shaped to receive approximately a hemispherical portion of the ball  96 , so that with the ball  96  received in the detent  74 , a portion of the ball  96  remains outside of the detent  74  in the bore  95 , and the ball  96  is located in an interference position juxtaposed with the tang  62 . The ball  96  is prevented from moving laterally along axis G with respect to the tang  62  by the detent  74  on one side of the ball  96  and the rod  97  on the other side of the ball  96 , so that the ball  96  defines an impedance to pivotal movement of the blade  51  that is fixed within the handle assembly  52 . With the ball  96  against the tang  62 , the blade  51  is prevented from moving between the open and closed positions. With both cams  92  and  92 ′ moved into the lowered positions thereof into the depressions  94  and  94 ′, and the rods  97  and  97 ′ moved into the advanced positions thereof in response to the movement of the cams  92  and  92 ′ into the lowered positions, and the balls  96  and  96 ′ located within the detents  74  and  73  in juxtaposition with the tang  62  of the blade  51 , the grip locking assemblies  90  and  91  each define a locked configuration in which the blade  51  is prevented from pivotal movement. The knife  50 ″ is then used while the user maintains the forward gripping arrangement on the knife  50 ″, thus maintaining the cams  92  and  92 ′ in the lowered positions and the grip locking assemblies  90  and  91  in the locked configurations during operation. 
     Attention is now directed back to  FIG. 1 . The blade  51  has opposed sides  51   a  and  51   b  and locking members  100  and  101  carried on sides  51   a  and  51   b , respectively. The locking members  100  and  101  define projections on the sides  51   a  and  51   b  to prevent the accidental movement of the blade from the open position to the closed position. The locking members  100  and  101  are identical in every respect to each other, other than location and as otherwise noted herein, and as such, reference will be made only with respect to the locking member  100  with the understanding that the discussion applies equally to the locking member  101 , and the constituent parts of the locking member  101  will be identified with a prime (“′”) to distinguish those parts from those of the locking member  100 . 
     The locking member  100  includes an elongate, slightly arcuate leaf  102  mounted within a depression  103  formed in the side  51   a  of the blade  51  at the tang  62 . The leaf  102  is thin and has opposed first and second ends  102   a  and  102   b  and an inner edge  102   c  directed toward the handle assembly  52 . The first end  102   a  is fixed to the blade  51  with a fastener, such as a bolt, a rivet, a weld, or the like, and the second end  102   b  defines a free end. The leaf  102  is proximate to the peripheral edge  52   a  of the handle assembly  52  and is aligned generally transverse with respect to the blade  51 , with the first end  102   a  proximate to the spine  65  of the blade  51  and the opposed second end  102   b  proximate to the edge  64  of the blade  51 . 
     The leaf  102  is constructed from a spring material having resilient and shape-memory material characteristics. The material characteristics and shape of the leaf  102  bias the leaf  102  outwardly away from the side  51   a  of the blade  51 , such that the second end  102   b  defines a projection above the side  51   a , arcuately curving away from the first end  102   a  secured within the depression  103 . The second end  102   b  is directed toward the direction of pivotal movement of the blade  51  from the open position to the closed position, preventing accidental depression of the leaf  102  from the raised position simply by closing the blade  51 . 
     The leaf  102  moves between a collapsed position and a raised position when the blade  51  is in the open position. In the closed position of the blade  51 , the leaf  102  is in the collapsed position and is maintained in the collapsed position by interaction with the liner  56 . As seen in  FIG. 7A , in the open position of the blade  51  and the raised position of the leaf  102 , the second end  102   b  of the leaf  102  is raised out of the depression and projects above the side  51   a . The inner edge  102   c  of the leaf  102  is in direct contact with the peripheral edge  52   a  of the handle assembly  52 , and the leaf  102  extends away from the handle assembly  52 . The direct juxtaposition of the inner edge  102   c  of the leaf  102  with the peripheral edge  52   a  of the handle assembly  52  in the raised position of the leaf  102 , prevents movement of the blade  51  from the open position to the closed position. 
     As seen in  FIG. 7B , in the open position of the blade  51  and the collapsed position of the leaf  102 , the second end  102   b  of the leaf  102  is depressed with respect to the handle assembly  52 , is depressed into the depression  103 , and is one of flush with and just inboard of the side  51   a , so as present a surface on the side  51   a  of the blade  51  that is free of impedance to the pivotal movement of the blade  51  from the open position to the closed position so as to allow the blade  51  to pivot from the open to the closed position. 
     The leaf  102  is moved into the collapsed position by taking up the knife  50 , as by hand, and depressing the second end  102   b  of the leaf  102  with a finger toward the blade  51 . The leaves  102  and  102 ′ may be simultaneously placed into the collapsed position by the user placing his fingers on each of the leaves  102  and  102 ′ and pinching his fingers into the blade  51 . 
     Attention is now directed to  FIG. 8 , which depicts the same knife  50  as in  FIG. 1  but shows a right half of the knife  50  in greater detail. A bolt locking assembly  110  is shown in exploded view. Bolt locking assembly  110  includes a first bolt  111  carried in the handle assembly  52 , a second bolt  112  carried in the handle assembly  52  (shown in  FIG. 1 ; not shown in  FIG. 8 ), and a linear compression spring  113  compressed between the first and second bolts  111  and  112 . 
     The first bolt  111  has an enlarged head  111   a , a hollow, co-axial shank  111   b  extending from the head  111   a  and terminating at an open end  111   c  along an axis J, and a lug  111   d  formed on the shank  111   b  at the open end  111   c . The lug  111   d  is a protuberance from a surface of the shank  111   b  and projects radially outward from the shank  111   b  along an axis indicated by line K in  FIG. 8 . 
     The second bolt  112  has an enlarged head  112   a , a hollow, co-axial shank  112   b  extending from the head  112   a  and terminating at an open end  112   c  along axis J, a lug  112   d  formed on the shank  112   b  at the open end  112   c , and an axial slot  112   e  offset from the lug  112   d  extending along the shank  112   b  from the open end  112   c  to the head  112   a . The shank  112   b  with the slot  112   e  defines a severed sleeve. The lug  112   d  projects radially outward from the shank  112   b  along an axis indicated by line L in  FIG. 8 . 
     The first and second bolts  111  and  112  are coaxial and are carried for reciprocation in the handle assembly  52  with respect to each other. Coaxial first and second bores  114  and  115  are formed through the handle assembly  52  and carry first and second bolts  111  and  112 . The first bore  114  is formed in the left handle portion  53  and is sized and shaped to receive the shank  111   b  proximate to the end  111   d  and the lug  111   d  for reciprocation of the first bolt  111  within the first bore  114 . The first bore  114  defines an opening  114   a  through the liner  56 ′ and the handle  55 ′, and includes a notch  114   b  extending radially outwardly away from the opening  114   a  along the line K. The opening  114   a  is sized to receive the head  112   a  of the second bolt  112 . The opening  114   a  in the handle  55 ′ includes an inner annular shoulder  114   c  to prevent the head  112   a , which is formed with a flange  112   f , from passing axially through the handle  55 ′. 
     The second bore  115  is formed in the right handle portion  54  and is sized and shaped to receive the shank  112   b  proximate to the end  112   d  and the lug  112   d  for reciprocation of the second bolt  112  within the second bore  115 . The second bore  115  defines an opening  115   a  through the liner  56  and the handle  55 , and includes a notch  115   b  extending radially outwardly away from the opening  115   a  along the line L. The opening  115   a  is sized to receive the head  111   a  of the first bolt  111 . The opening  115   a  in the handle  55  includes an inner annular shoulder  115   c  to prevent the head  111   a , which is formed with a flange  111   e , from passing axially through the handle  55 . 
     In operation, the bolt locking assembly  110  is useful for locking and unlocking the blade  51  into the open and closed positions of the blade  51 . The first bolt  111  fits within a bore  112   g  formed in the second bolt  112 , with the lug  111   d  protruding through the slot  112   e  beyond the shank  112   b  of the second bolt  112 , so that the first bolt  111  is free to reciprocate within the bore  112   g  of the second bolt  112  and the lug  111   d  is free to reciprocate within the slot  112   e . The lugs  111   d  and  112   d  extend radially outward along respective axes along lines K and L, respectively, and are radially offset by an amount θ, which is preferably 40 degrees but could be another amount as will be understood. The spring  113  is located between the first and second bolts  111  and  112  and exerts an axial bias outwardly on each of the first and second bolts. 
     The tang  62  of the blade  51  is formed with structure to engage with the first and second bolts  111  and  112 . With reference to  FIG. 9 , which shows the blade and the bolt locking assembly in greater detail, the arcuate outer edge  62   a  of the tang  62  includes the first, second, and third notches  116 ,  117 , and  118 . The first and second notches  116  and  117  are directed toward the spacer  57  when the blade  51  is in the open position. The first and second notches  116  and  117  are radially spaced apart on the outer edge  62   a  and aligned with lines K and L, respectively, along which lugs  111   d  and  112   d  extend, and are shaped to receive lugs  111   d  and  112   d , respectively. A projection, or finger  119 , extends radially outward from the tang  62  between the notches  116  and  117  to define and separate the notches  116  and  117 . 
     With the blade  51  in the open position, the lug  111   d  reciprocates past the notch  116  along axis J, and the lug  112   d  reciprocates past the notch  117  along axis J. Reference is now made to  FIG. 10 , which shows the bolt locking assembly  110  engaged with the tang  62  and the blade  51  pivoted about axis C into the open position of the blade  51 . The lugs  111   d  and  112   d  are aligned with the arcuate outer edge  62   a  and are closely received within the notches  116  and  117 , respectively, as shown in  FIG. 11 . Although not visible in  FIG. 10 , the lug  111   d  is fit within both the notch  116  and the notch  114   b  in the handle  55 ′ and the liner  56 ′, so that the lug  111   d  is fixed with respect to the handle  55 ′ and the first bolt  111  is prevented from rotational movement about axis J by the interaction of the lug  111   d  with the notch  114   b . Similarly, the lug  112   d  is fit within both the notch  117  and the notch  115   b  in the handle  55  and the liner  56 , so that the lug  112   d  is fixed with respect to the handle  55  and the second bolt  112  is prevented from rotational movement about axis J by the interaction of the lug  112   d  with the notch  115   b . With the lugs  111   d  and  112   d  are each engaged with the tang  62  in an interference position, and the blade  51  in the open position, the bolt locking assembly  110  is arranged in a locked configuration preventing the rotation of the blade  51  from the open position toward the closed position. 
     To move the blade  51  from the open position to the closed position, the bolt locking assembly  110  must be moved from the locked configuration to an unlocked configuration. To do so, the user places his fingers on the heads  111   a  and  112   a  and depresses the first and second bolts  111  and  112  inward along axis J. The first bolt  111  is depressed along axis J in a direction indicated by arrowed line M in  FIG. 11  until the lug  111   d  is opposite the tang  62  from the head  111   a  of the first bolt  111 , proximate to the left face  62   b  of the tang  62 , as shown in  FIG. 12 . Movement along line M is limited by the interaction of the open end  111   c  with the head  112   a . Similarly, the second bolt  112  is depressed along axis J in a direction indicated by arrowed line N in  FIG. 11  until the lug  112   d  is opposite the tang  62  from the head  112   a  of the second bolt  112 , proximate to the right face  62   c  of the tang  62 , as shown in  FIG. 12 . Movement along line N is limited by the interaction of the open end  112   c  with the head  111   a . In this condition, shown in  FIG. 12 , the bolt locking assembly  110  is in an unlocked configuration and the lugs  111   d  and  112   d  define a groove  120 , formed between the lugs  111   d  and  112   d , in which the outer edge  62   a  of the tang  62  is received during pivotal movement of the blade  51  between the deployed and closed positions. The blade  51  is then rotated between the open and closed positions with the bolt locking assembly  110  in the unlocked configuration. When the blade is moved to the open or closed position and the user releases his fingers from the first and second bolts  111  and  112 , the spring  113  compressed between the first and second bolts  111  and  112  urges both the first and second bolts  111  and  112  back into the locked configurations in which the first and second bolts  111  and  112  are in an interference position with the tang  62 . 
     Attention is now directed to  FIG. 13 , which shows the blade  51  in the closed position. The third notch  118  formed in the arcuate outer edge  62   a  of the tang  62  is opposite the tang  62  from the first and second notches  116  and  117  and is aligned with line L along which the lug  112   d  extends when the blade  51  is in the closed position. The lug  112   d  is aligned with the arcuate outer edge  62   a  and is closely received within the notch  118 . The lug  112   d  is fit within both the notch  118  and the notch  115   b  in the handle  55  and the liner  56 , so that the lug  112   d  is fixed and the second bolt  112  is prevented from rotational movement about axis J by the interaction of the lug  112   d  with the notch  115   b . With the lug  112   d  engaged with the tang  62  in an interference position, and the blade  51  in the closed position, the bolt locking assembly  110  is arranged in a locked configuration preventing the rotation of the blade  51  from the closed position toward the open position. While in this illustration only the second bolt  112  is depicted as preventing movement out of the closed position of the blade  51 , one having skill in the art will readily appreciate that another notch formed in the tang  62  apart from the notch  118  and aligned with the lug  111   d  would allow the first bolt  111  to secure the blade  51  in the locked configuration. 
     As shown in  FIG. 14 , to release the bolt locking assembly  110  from the locked configuration, the user places his fingers on the head  112   a  and depresses the second bolt  112  inward along axis J, moving the second bolt  112  along axis J in a direction indicated by the arrowed line N, until the lug  112   d  is opposite the tang  62  from the head  112   a  of the second bolt  112 , proximate to the right face  62   c  of the tang  62 . The first bolt  111  is already depressed along axis J with the lug  111   d  opposite the tang  62  from the head  111   a  of the first bolt  111 . The blade is then free to pivot from the closed position to the open position. 
     An alternate embodiment of the bolt locking assembly  110  is shown in  FIG. 15  and is referenced as a bolt locking assembly  130 . The bolt locking assembly  130  includes a first bolt  131  carried in the handle assembly  52 , a second bolt  132  carried in the handle assembly  52 , and a spring  133  between the first and second bolts  131  and  132 . 
     The first bolt  131  has an enlarged head  131   a , a hollow, co-axial shank  131   b  extending from the head  131   a  and terminating at an open end  131   c  along an axis P, and a lug  131   d  formed on the shank at the open end  131   c . The lug  131   d  projects radially outward from the shank  131   b  along an axis indicated by line Q in  FIG. 15 . 
     The second bolt  132  has an enlarged head  132   a , a hollow, co-axial shank  132   b  extending from the head  132   a  and terminating at an open end  132   c , a slotted lug  132   d  formed on the shank  132   b  at the open end  132   c , and an axial slot  132   e  extending along the shank  132   b  from the open end  132   c  to the head  132   a  through the lug  132   d . The lug  132   d  projects radially outward from the shank  132   b  along an axis generally indicated by line R in  FIG. 15 . Lines Q and R are aligned and parallel, so that the lugs  131   d  and  132   d  are aligned axially and aligned circumferentially on bolts  131  and  132 , respectively. The lug  132   d  is formed with a cutout  132   f  communicating with the open end  132   c  and the slot  132   e  to allow the second bolt  132  to encircle and receive the open end  131   c  and the shank  131   b  of the first bolt  131  in reciprocation. 
       FIG. 15  illustrates an alternate embodiment of the blade  51  with the tang  62  having two opposed notches  134  and  135  formed in the arcuate outer edge  62   a  of the tang  62 . The notch  134  is formed completely through the tang  62  between the left and right faces  62   b  and  62   c . The notch  134  has a staggered profile through the tang  62 . The notch  134  proximate to the right face  62   c  has a height that is greater than the height of the notch  134  proximate to the left face  62   b . The height of the notch  134  proximate to the right face  62   c  corresponds to the lug  132   d  so as to receive the lug  132   d . The height of the notch  134  proximate to the left face  62   b  corresponds to the lug  131   d  so as to receive the lug  131   d . The lug  132   d  defines a key, and the notch  135  is a keyway, or blind channel, extending partially into the right face  62   c  for receiving the slotted lug  132   d  of the second bolt  132 . One having skill in the art will understand that the bolt locking assembly  130  works in the same fashion as the bolt locking assembly  110 , with the first and second bolts  131  and  132  reciprocating along axis P to alternately engage and disengage with the tang  62  to lock and unlock, respectively, the blade  51 . In the closed position of the blade  51  and the locked configuration of the bolt locking assembly  130 , the first bolt  131  is depressed along axis P with the lug  131   d  opposite the tang  62  from the head  131   a  of the first bolt  131 , and the lug  132   d  of the second bolt  132  received in contact in the notch  135  on the tang  62 , preventing movement of the blade  51 . 
     An alternate embodiment of the bolt locking assembly  110  for use with the knife  50  is shown in  FIG. 16  and is referenced as a bolt locking assembly  140 . The bolt locking assembly  140  includes a first bolt  141  carried in the handle assembly  52  (not shown), an opposed second bolt  142  carried in the handle assembly  52 , and a spring  143  between the first and second bolts  141  and  142 . 
     The first bolt  141  has an enlarged head  141   a , a hollow co-axial shank  141   b  extending from the head  141   a  and terminating at an open end  141   c , an upstanding lug  141   d  formed on the circumference of the shank  141   b  at the open end  141   c , and an axial slot  141   e  extending along the shank  141   b  from the open end  141   c  to the head  141   a . The shank  141   b  with the slot  141   e  defines a severed sleeve. The lug  141   d  projects radially outward from the shank  141   b  along an axis indicated by line X in  FIG. 16  proximate to the slot  141   e . The lug  141   d  is offset to a side of the shank  141   b  opposite the slot  141   e.    
     The second bolt  142  has an enlarged head  142   a , a hollow-co-axial shank  142   b  extending from the head  142   a  and terminating at an open end  142   c , and an upstanding lug  142   d  formed on the circumference of the shank  142   b  at the open end  142   c . The lug  142   d  is offset to a side of the shank  142   b  and projects radially outward from the shank  142   b  along an axis indicated by line Y in  FIG. 16 . As seen in the section view of  FIG. 17 , the lugs  141   d  and  142   d  are circumferentially offset with respect to each other, and the axes X and Y of the lugs  141   d  and  142   d  are parallel. In this way, the lugs  141   d  and  142   d  define a single projection for interference with the tang  62 . 
       FIG. 16  also illustrates an embodiment of the blade  51  with the tang  62  formed with two opposed blind notches  144  and  145  extending partially into the tang  62  from the left and right faces  62   b  and  62   c , respectively. The notch  144  is formed between the arcuate outer edge  62   a  and the left face  62   b  and extends into the tang  62  to a generally intermediate location between the left and right faces  62   b  and  62   c . The notch  144  is rectangular and corresponds to the lug  141   d  so as to receive the lug  141   d  snugly. The notch  145  is formed between the arcuate outer edge  62   a  and the right face  62   c  and extends into the tang  62  to a generally intermediate location between the left and right faces  62   b  and  62   c . The notch  145  is rectangular and corresponds to the lug  142   d  so as to receive the lug  142   d  snugly. 
     During operation, the first and second bolts  141  and  142  of the bolt locking assembly  140  reciprocate with respect to each other. The first and second bolts  141  and  142  are coaxial, and the shank  142   b  of the second bolt  142  is received coaxially within the shank  141   b  of the first bolt  141  so that the second bolt  142  is encircled by the first bolt  141 . The lug  142   d  projects outward from the side of the shank  142   b  of the second bolt  142  through the slot  141   e  of the first bolt  141 . The spring  143  is held within the shank  142   b  and is compressed between the heads  141   a  and  142   a  so as to exert an axial bias outward along line Z in  FIG. 16 . 
     A notch  146  is formed in the arcuate outer edge  62   a  opposite the notches  144  and  145 . The notch  146  is formed between the left face  62   b  and the arcuate outer edge  62   a  and extends into the tang  62  from the left face  62   b  to a generally intermediate location between the left and right faces  62   b  and  62   c . The notch  146  is rectangular and corresponds to the lug  141   d  so as to receive the lug  141   d  snugly. 
     In operation, when the blade  51  is in the open position, the first and second bolts  141  and  142  interlock with the tang  62  to lock the blade  51  in the open position. The spring  143  biases the first and second bolts outward along line Z so that the lug  141   d  is biased into an interference fit with the notch  144  and so that the lug  142   d  is biased into an interference fit with the notch  145 . In this way, the bolt locking assembly  140  is in a locked configuration and the blade  51  is prevented from rotating from the open position to the closed position. 
     To move the blade  51  from the open position to the closed position, the bolt locking assembly  140  must be moved from the locked configuration to the unlocked configuration. One having ordinary skill in the art will appreciate that the steps involved in moving the bolt locking assembly  110  from the locked configuration to the unlocked configuration, as described above, are generally the same as those for moving the bolt locking assembly  140  from the locked configuration to the unlocked configuration. When the bolt locking assembly  140  is in the unlocked configuration and the blade  51  is in the open condition, the lugs  141   d  and  142   d  are retracted out of the notches  144  and  145 , respectively, and are just off the left and right faces  62   b  and  62   c , respectively, of the tang  62  so that the blade  51  may be moved from the open condition to the closed position. With the blade  51  moved into the closed position, the first and second bolts  141  and  142  are released from the user&#39;s fingers, and the spring  143  biases the first and second bolts  141  and  142  apart. The lug  141   d  on the first bolt  141  is received in the notch  146 , and the lug  142   d  is received in contact against the right face  62   c , defining a locked configuration of the bolt locking assembly  140  when the blade is in the closed position. One having skill in the art will understand that this arrangement could be reversed or that both lugs  141   d  and  142   d  could be received in notch  146  and another notch formed proximate to notch  146 . 
     Turning now to  FIG. 18 , another embodiment according to the present invention is illustrated and identified as a knife  150 . The knife  150  includes features identical to that of the knife  50 , as indicated with common reference numbers. However, the knife  150  carries a different bolt locking assembly  151 , and the tang  62  is formed with different notches  152 ,  153 , and  154 . 
     The bolt locking assembly  151  includes a first bolt  155  carried in the right handle portion  54  and a second bolt  156  carried in the left handle portion  53 . The first and second bolts  155  and  156  are carried in offset, elbow-shaped bores  157  and  158  for reciprocation. The bores  157  and  158  define a common channel through liners  56  and  56 ′ in which both bolts  155  and  156  reciprocate in sliding contact side-by-side, against and alongside each other. 
     With reference now to  FIG. 19 , which shows the bolt locking assembly  151  in greater detail, the first bolt  155  has a proximal end  155   a , an opposed distal end  155   b , a prismatic shank  155   c  extending between the proximal and distal ends  155   a  and  155   b , and an upstanding lug  155   d  at the distal end  155   b . A cylindrical button  160  is fixed to the proximal end  155   a  of the first bolt  155 . The button  160  is formed with a prismatic recess  160   a  for receiving the proximal end  155   a  of the first bolt  155  and with a bore  160   b  extending from an annular sidewall  160   c  of the button  160  through the button  160  into the recess  160   a . The proximal end  155   a  of the first bolt  155  is formed with a transverse bore  155   e  entirely through the first bolt  155 , and when the proximal end  155   a  of the first bolt  155  is received in the recess  160   a , the bores  160   b  and  155   e  are aligned and a pin  161  is frictionally fit in the bores  160   b  and  155   e  to secure the button  160  on the first bolt  155 . 
     Referring briefly back to  FIG. 18 , the button  160  is received in a socket  162  formed through the handle  55 . The socket  162  has a first bore  162   a  extending into the handle  55  from the outer surface  55   a , and a larger diameter, co-axial second bore  162   b  extending into the handle  55  from the inner surface  55   b . The button  160  is received in the socket  162  and has an inner annular flange  160   d  which corresponds in diameter to the second bore  162   b . With the button  160  fit in the socket  162 , the button  160  is flush with the outer surface  55   a  of the handle  55  so that the button  160  is available to be depressed by the user. The button  160  is limited from moving out of the socket  162  by the interaction of the flange  160   d  with the smaller-diameter first bore  162   a.    
     With continuing reference back to  FIG. 18 , a washer  163  and a conical spring  164  are applied on the shank  155   c  and located in the second bore  162   b  between the button  160  and the liner  56 . The spring  164 , compressed against the washer  163  which is against the liner  56 , urges the button  160  outwardly into the handle  55  and the first bolt  155  outwardly so as to locate the lug  155   d  in an interference position with the tang  62 . The lug  155   d  is received in the notch  153 . Now returning back to  FIG. 19 , the notch  153  is formed on the tang  62  between the left face  62   b  and the arcuate outer edge  62   a , extends into the tang  62  to a location generally intermediate between the left and right faces  62   b  and  62   c , and is sized and shaped to receive the lug  155   d  on the distal end  155   b  of the first bolt  155 . With the spring  164  biasing the lug  155   d  into the notch  153 , the tang  62  is locked and the blade  51  is prevented from rotating. 
     With continuing reference to  FIG. 19 , the second bolt  156  has a proximal end  156   a , an opposed distal end  156   b , a prismatic shank  156   c  extending between the proximal and distal ends  156   a  and  156   b , and an upstanding lug  156   d  at the distal end  156   b . A cylindrical button  170  is fixed to the proximal end  156   a  of the second bolt  156 . The button  170  is formed with a prismatic recess  170   a  for receiving the proximal end  156   a  of the second bolt  156  and a bore  170   b  extending from an annular sidewall  170   c  of the button  170  through the button  170  into the recess  170   a . The proximal end  156   a  of the second bolt  156  is formed with a transverse bore  156   e  entirely through the second bolt  156 , and when the proximal end  156   a  of the second bolt  156  is received in the recess  170   a , the bores  170   b  and  156   e  are aligned and a pin  171  is frictionally fit in the bores  170   b  and  156   e  to secure the button  170  on the second bolt  156 . 
     Referring briefly back to  FIG. 18 , the button  170  is received in a socket  172  formed through the handle  55 ′. The socket  172  has a first bore  172   a  extending into the handle  55 ′ from the outer surface  55   a ′, and a larger diameter, co-axial second bore  172   b  extending into the handle  55 ′ from the inner surface  55   b ′. The button  170  is received in the socket  172  and has an inner annular flange  170   d  which corresponds in diameter to the second bore  172   b . With the button  170  fit in the socket  172 , the button  170  is flush with the outer surface  55   a ′ of the handle  55 ′ so that the button  170  is available to be depressed by the user. The button  170  is limited from moving out of the socket  172  by the interaction of the flange  170   d  with the smaller-diameter first bore  172   a.    
     A washer  173  and a conical spring  174  are applied on the shank  156   c  and located in the second bore  172   b  between the button  170  and the liner  56 ′. The spring  174 , compressed against the washer  173  which is against the liner  56 ′, urges the button  170  outwardly into the handle  55 ′ and the second bolt  156  outwardly so as to locate the lug  156   d  in an interference position with the tang  62 . The lug  156   d  is received in the notch  152 . The notch  152  is formed on the tang  62  between the right face  62   c  and the arcuate outer edge  62   a , extends into the tang  62  to a location generally intermediate between the left and right faces  62   b  and  62   c , and is sized and shaped to receive the lug  156   d  on the distal end  156   b  of the second bolt  156 . With the spring  174  biasing the lug  156   d  into the notch  152 , the tang  62  is locked and the blade  51  is prevented from rotating. 
     With the blade  51  in the open position and the first and second bolts  155  and  156  urged outward so as to locate the lugs  155   d  and  156   d  in the notches  153  and  152 , respectively, the blade  51  is locked and the bolt locking assembly  151  is arranged in a locked configuration preventing pivotal movement of the blade  51  from the open to the closed position. To move the blade  51  from the open position to the closed position, the user need only depress, as by the user&#39;s fingers, each of the buttons  160  and  170  inwardly, overcoming the spring force of the springs  164  and  174 , so as to move the lugs  155   d  and  156   d  out of the notches  153  and  152 , respectively, so that the lugs  155   d  and  156   d  are moved out of the interference position with tang  62 . While the buttons  160  and  170  are depressed, the blade is pivoted into the closed position. In this position, the buttons  160  and  170  are released, and the lug  156   d  is urged, by the spring  174 , into the notch  154 . The notch  154  is formed on the tang  62  between the right face  62   c  and the arcuate outer edge  62   a , extends into the tang  62  to a location generally intermediate between the left and right faces  62   b  and  62   c , and is sized and shaped to receive the lug  156   d  on the distal end  156   b  of the second bolt  156 . One having skill in the art will understand that a second notch could be formed proximate to the notch  154  for receiving the lug  155   d  when the blade  51  is in the closed position, or that the notch  154  could be formed on the left face  62   b  and receive the lug  155   d . In the embodiment described above, the blade  51  is secured in a closed position and the bolt locking assembly  151  is in a locked configuration with respect to the closed position of the blade  51 . 
     Attention is now directed to  FIG. 20 , which illustrates an alternate embodiment of a bolt locking assembly identified with the reference character  180 . The bolt locking assembly  180  includes a first bolt  181 , a second bolt  182 , and two linear compression springs  183  and  184  compressed between the first and second bolts  181  and  182 . 
     The first bolt  181  has an enlarged head  181   a , a semi-cylindrical shank  181   b  extending from the head  181   a  and terminating at an end  181   c , and an upstanding lug  181   d  formed on the shank  181   b  at the end  181   c . The lug  181   d  is a projection from a surface of the shank  181   b  and projects radially outward from the shank  181   b.    
     The second bolt  182  has an enlarged head  182   a , a semi-cylindrical shank  182   b  extending from the head  182   a  and terminating at an end  182   c , and an upstanding lug  182   d  formed on the shank  182   b  at the end  182   c . The lug  182   d  is a projection from a surface of the shank  182   b  and projects radially outward from the shank  182   b.    
     The first and second bolts  181  and  182  are carried for reciprocation past each other in the handle assembly  52  (not shown). The shanks  181   b  and  182   b  of the first and second bolts  181  and  182  are each formed with flat, inner faces  181   e  and  182   e , respectively. The inner faces  181   e  and  182   e  are parallel and aligned with each other, so that during reciprocation of the first and second bolts  181  and  182 , the inner faces  181   e  and  182   e  are received in sliding contact against and along each other. As seen in  FIG. 21 , the lugs  181   d  and  182   d  extend radially outward along respective axes, respectively, and are radially offset by an amount θ, which is preferably 40 degrees but could be another amount as will be understood by one having ordinary skill in the art. With reference back to  FIG. 20 , the spring  183  is located between the head  181   a  of the first bolt  181  and the liner  56  (not shown), and the spring  184  is located between the head  182   a  of the second bolt  182  and the liner  56 ′ (not shown). The springs  183  and  184  urge the first and second bolts  181  and  182  axially outward. 
     The tang  62  is formed with structure to engage with the first and second bolts  181  and  182 . The tang  62  includes notches  190 ,  191 , and  192  formed along the arcuate outer edge  62   a . The notches  190  and  191  are directed toward the spacer  57  when the blade  51  is in the open position, and the notch  192  is directed toward the spacer  57  when the blade  51  is in the closed position. The notches  190 ,  191 , and  192  are radially spaced apart about the arcuate outer edge  62   a , and are shaped to receive the lug  182   d ,  181   d , and  182   d , respectively. 
     With the blade  51  in the open position, the spring  183  urges the first bolt  181  axially outward so as to locate the lug  181   d  in the notch  191  in an interference fit. Likewise, the spring  184  urges the second bolt  182  axially outward so as to locate the lug  182   d  in the notch  190  in an interference fit. In this way, the lugs  181   d  and  182   d  engage the tang  62  to prevent the blade  51  from pivoting, defining a locked configuration on the bolt locking assembly  180 . To move the blade  51  from the open position to the closed position, the heads  181   a  and  182   a  are depressed, as by a user&#39;s fingers, to move the lugs  181   d  and  182   d  out of the notches  191  and  190 , respectively. In this way, the blade  51  is free to pivot from the open position to the closed position, and the heads  181   a  and  182   a  are then released, allowing the springs  183  and  184  to bias the first and second bolts  181  and  182  axially outward, so that the lug  182   d  is received in the notch  192 . As one having skill in the art will readily appreciate, the blade  51  is locked in the closed position by the second bolt  182  alone, but could be locked by the first bolt  181  alone, or by both the first and second bolts  181  and  182  with the addition of additional notches to the tang  62  as described above with reference to other embodiments. 
     With reference now to  FIG. 22 , a cap assembly  200  is illustrated. The cap assembly  200  is useful for preventing the accidental depression of the first and second bolts  111  and  112  out of the locked configuration of the bolt locking assembly  110 . The cap assembly  200  is shown in  FIG. 22  configured over the first bolt  111 , but it should be understood that the cap assembly  200  is similarly configured over the second bolt  112 , the first bolt  131 , and the second bolt  132 . 
     The cap assembly  200  includes a cap  201  mounted for pivotal movement to the head  111   a  of the first bolt  111  about an axis S between a locked position and an operative position. The cap  201  is cylindrical and has a diameter D1. The cap  201  includes an outer face  202 , an opposed inner face  203  held against the head  111   a , and a bore  204  extending through the cap  201  from the outer face  202  to the inner face  203  at axis S. A corresponding threaded bore  205  aligned with the bore  204  extends into the head  111   a  of the first bolt  111 . A screw  206  is set into the bore  204 , through the cap  201 , and is threadably engaged with the threaded bore  205 . The screw  206  has an enlarged head  206   a  and a threadless shank  206   b  extending from the head  206   a  and terminating in a threaded portion  206   c . The enlarged head  206   a  is seated in the bore  204 , preventing axial movement of the cap  201  off the head  111   a  of the first bolt  111 , the threaded portion  206   c  is threadably engaged with the threaded bore  205  in the first bolt  111 , and the cap  201  encircles the threadless shank  206   b  so that the cap  201  may pivot about the axis S and the screw  206  installed along axis S. 
     With reference now to  FIG. 22  as well as to the sequence of  FIGS. 23A ,  23 B, and  24 A- 24 C, the cap  201  moves between the locked and operative positions. An axially-projecting post  210  is carried on the head  111   a  of the first bolt  111  extending out toward the cap  201 . The inner face  203  of the cap is formed with a depression  211  for receiving the post  210 . The depression has an inner sidewall  212  extending around the cap  201 . A torsional spring  213  secured about the threadless shank  206   b  has outwardly extending fingers in contact with the post  210  and the inner sidewall  212 , such that the spring  213  is compressed between the post  210  and the sidewall  212 . The spring  213  biases the cap  201  off the head  111   a  until the inner sidewall  212  contacts the post  210 , limiting further movement of the cap  201  with respect to the head  111   a . When the first bolt  111  is in the locked configuration, the head  111   a  is located flush at the outer surface  55   a  of the handle  55 , and the spring  213  biases the cap  201  into a locked position in which the cap  201  is offset from the head  111   a  of the first bolt  111 , as shown in  FIG. 23A , thus preventing depression of the first bolt  111 . The head  111   a  has a diameter D2, and the diameter D1 of the cap  201  is equal to the diameter D2, so that when the cap  201  is offset from the head  111   a , a portion of the inner face  203  is in contact with the outer surface  55   a  of the handle  55  and prevents axial translation of the first bolt  111  into the handle assembly  52  into the unlocked configuration. 
     To move the cap assembly  200  from the locked position, shown in  FIG. 23A  and  FIG. 24A , to the operative position, shown in  FIG. 23B  and  FIG. 24B , in which the first bolt  111  may be depressed, the user need only apply force to the cap  201  about axis S in a direction opposite to that urged by the spring  213 , as indicated by the curved line T in  FIG. 23A , moving the cap  201  from an offset position to an aligned position with respect to the head  111   a  as shown in  FIG. 23B  and  FIG. 24B . Curved line T lies in a plane normal to the axis S and to the axis J along which the first and second bolts  111  and  112  reciprocate. Because the diameters D1 and D2 of the cap  201  and head  111   a  are equal, the cap  201  may now pass through the second bore  115  so that the first bolt  111  may be depressed along line U toward the unlocked configuration of the bolt locking assembly  110  to move the blade  51 , as shown in  FIG. 24C . The cap  201  is depressed until the outer face  202  of the cap  201  is flush with the outer surface  55   a  of the handle  55 . 
     After the user has moved the blade  51  into the desired position, the user merely releases the first bolt  111  and the cap  201 , and the spring  113  urges the first bolt  111  back into the locked configuration of the bolt locking assembly  110  with the head  111   a  of the first bolt  111  located at the outer surface  55   a  of the handle  55 , and the spring  213  urges the cap  201  back into the offset position. In this manner, the knife  50  can be operated without accidentally moving the bolt locking assembly  110 . An access bore  214  is formed through the cap  201  from the outer face  202  to the inner face  203  to provide access to the spring  213  with a small tool such as a pin or paper clip so as to aid in assembly of the cap assembly  200  on the first bolt  111 . 
     A cap assembly  220  in an alternate embodiment from that of the cap assembly  200  is shown in  FIG. 25 . The cap assembly  220  is useful for preventing the accidental depression of the first and second bolts  111  and  112  out of the locked configuration of the bolt locking assembly  110 . The cap assembly  220  is shown in  FIG. 25  configured over the first bolt  111 , but it should be understood that the cap assembly  220  is similarly configured over the second bolt  112 , the first bolt  131 , and the second bolt  132 . 
     The cap assembly  220  includes a cap  221  mounted for translational movement to the head  111   a  of the first bolt  111  along a line V between a locked position and an operative position. The cap  221  is cylindrical and has a diameter D3. The cap  221  includes an outer face  222 , an opposed inner face  223  held against the head  111   a , a recessed face  223   a  inboard of the inner face  223 , and an elongate bore  224  extending through the cap  221  from the outer face  222  to the inner face  223 . A corresponding threaded bore  225  aligned with the bore  224  extends into the head  111   a  of the first bolt  111 . A screw  226  is set into the bore  224 , through the cap  221 , and is threadably engaged with the threaded bore  225 . The screw  226  has an enlarged head  226   a  and a threadless shank  226   b  extending from the head  226   a  and terminating in a threaded portion  226   c . The enlarged head  226   a  is seated in the bore  224  for reciprocal movement of the cap  221  along line V with respect to the first bolt  111 , preventing axial movement of the cap  221  off the head  111   a  of the first bolt  111 , and the threaded portion  226   c  is threadably engaged with the threaded bore  225  in the first bolt  111 . Line V is aligned parallel to the outer surface  55   a  of the handle  55  and is normal to the axis J along which the first and second bolts  111  and  112  reciprocate. 
     With reference now to  FIG. 25  as well as the sequence of  FIGS. 26A and 26B , the cap  221  translates between the locked and operative positions. An axially-projecting post  230  is carried on the recessed inner face  223   a  of the cap  221  and extends out toward the head  111   a . A slot  231  extends into the head  111   a  opposite the post  230  and is aligned with the elongate bore  224  along line V. The slot  231  is sized to receive the post  230  and allow the post  230  to reciprocate along line V within the slot  231 . A spring  232  is secured on the threadless shank  226   b  and on the post  230 . When the first bolt  111  is in the locked configuration with the head  111   a  located flush at the outer surface  55   a  of the handle  55 , the spring  232  biases the cap  221  into the locked position in which the cap  221  is offset from the head  111   a  of the first bolt  111 , as shown in  FIG. 26A , thus preventing depression of the first bolt  111 . The diameter D3 of the cap  221  is equal to the diameter D2, so that when the cap  221  is offset from the head  111   a , a portion of the inner face  223  is in contact with the outer surface  55   a  of the handle  55  and prevents axial movement of the first bolt  111  into the handle assembly  52  into the unlocked configuration. 
     To move the cap assembly  220  from the locked position, shown in  FIG. 26A , to the operative position, shown in  FIG. 26B , in which the first bolt  111  may be depressed, the user need only apply force to the cap  221  in a direction along the arrowed line V in  FIG. 26A  opposite to the bias urged by the spring  232 , moving the cap  221  from an offset position to an aligned position with respect to the head  111   a  as shown in  FIG. 26B . Because the diameters D3 and D2 of the cap  221  and head  111   a  are equal, the cap  221  may now pass through the second bore  115  so that the first bolt  111  may be depressed along line U toward the unlocked configuration of the bolt locking assembly  110 . The cap  221  is depressed until the outer face  222  of the cap  221  is flush with the outer surface  55   a  of the handle  55 . 
     After the user has moved the blade  51  into the desired open or closed position, the user merely releases the first bolt  111  and the cap  221 , and the first bolt  111  is urged back into the locked configuration of the bolt locking assembly  110  with the head  111   a  of the first bolt located at the outer surface  55   a  of the handle  55 , and the spring  232  urges the cap  221  back into the offset position. In this manner, the knife  50  can be operated without accidentally moving the bolt locking assembly  110  into the unlocked configuration. 
     The present invention is described above with reference to a preferred embodiment. However, those skilled in the art will recognize that changes and modifications may be made in the described embodiment without departing from the nature and scope of the present invention. 
     One having skill in the art will recognize that changes and modifications may be made in the above described embodiment without departing from the nature and scope of the present invention. Various further changes and modifications to the embodiments disclosed herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extend that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof. 
     Having fully described the invention in such clear and concise terms as to enable one having skill in the art to understand and practice the same, the invention claimed is: