Abstract:
A liner lock folding knife with an improved liner lock mechanism which provides increased safety in use. The locking mechanism provides for simple one-handed operation and the ability to tactilely know when the blade is securely locked in the open position.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to folding knives, and in particular to an improved blade-locking mechanism for a folding knife with added safety features. 
         [0002]    The prior art employed a liner lock to keep the blade of the folding knife locked in place while in use and will be well known to one familiar with the art. A liner is a thin metal sheet that is placed along the inside of the scale of a folding knife, next to the blade. A section of this liner is cut and bent to produce a spring action so that when the blade is opened, it snaps inward, wedging itself against the blade and thus locking the blade in the open position. The lock is also cut in such a way that the lower edge extends slightly below the edge of the scale. To disengage the lock, pressure is exerted against this edge to push the locking element of the scale back against the body of the scale, freeing the blade so that it may be closed. 
         [0003]    Such a design has been disclosed in Walker U.S. Pat. No. 4,896,424 and Weatherly U.S. Pat. No. 5,755,035 where a locking finger is cut into the liner of a folding knife and engages with the back of the blade locking it in the open position. 
         [0004]    This design can create complications for the user. In order to open the blade, the user must either pull out the blade with the fingers from the opposite hand, or use a thumb stud, thumb hole built into the blade or flipper built into the blade, if opening the knife one-handedly. Even with these modifications, one-handed opening can be difficult, particularly if the user is wearing gloves or if the knife or hands are wet. Typically, the user relies on a “click” as the blade settles into the lock to inform them that the lock has engaged. If the lock fails to fully engage as a result of the aforementioned complications or due to its design, the blade could close unexpectedly on the user&#39;s fingers and cause injury. To unlock and close the knife, the user has to press the locking element against the side of the knife handle, and in the process, the user&#39;s fingers are put in the path of the blade, which also risks injury. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The present invention uses a unique lock design and floating pivot which work in tandem to create the locking and unlocking actions and should be understood by one familiar with the art. The liner inside the knife handle acts as the lock, similar to knives of the prior art, but in the present invention the lock is cut from within the center of the liner, rather than along the edge of the liner. The lock terminates at the floating pivot, which is the mechanism that allows the blade to pivot and acts as a release for the lock and allows the user to tactilely detect that the blade is fully engaged. This lock is bent in such a way as to provide a spring action which facilitates the engagement of the lock. To facilitate opening the blade, a tang is provided which extends outward from the back of the blade. Rotational pressure on the tang allows for opening the blade with one hand, even in non-optimal conditions. As the blade is opened, the lock is automatically engaged by the force of the spring, pushing the lock into the notch which has been cut into the blade. The terminal end of the lock resides in a groove which is cut into the body of the floating pivot and when the lock is engaged, it pushes the floating pivot from one side of the knife to the other. To disengage the lock, the floating pivot is pressed to the opposite side of the knife, returning it to its original position, which forces the lock out of the notch in the blade and against the scale, freeing the blade and allowing it to fold shut. The position of the floating pivot prevents the user&#39;s fingers from being in the path of the blade at any time. 
         [0006]    The present invention&#39;s locking mechanism and ease of use resolve the concerns related to the prior art, which were noted in THE BACKGROUND OF THE INVENTION. Whereas folding knives of the prior art have no simple way to discern whether a lock is fully engaged, the present invention&#39;s floating pivot serves as both a visual and tactile method to detect whether the knife has been properly locked. Furthermore, the user can keep the thumb on the pivot during use as a safety precaution. By disengaging the lock at the pivot, the user does not have to place their fingers in the travel of the closing blade and the risk of injury is reduced. Additionally, the present invention&#39;s design improves the ease of use tremendously over knives in the prior art. The user can easily disengage the lock with one hand, even in poor weather or while wearing gloves. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0007]      FIG. 1  is an exploded view of the knife. 
           [0008]      FIG. 2  shows a detailed view of the floating pivot in end view and cross-section view, as well as a view of the floating pivot attached to the liner. 
           [0009]      FIG. 3  is a cross section view through the center of the floating pivot showing the lock engaged and disengaged. 
           [0010]      FIG. 4  shows the fully assembled knife, with the blade opened and the stone insets in place. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    The exploded view of the knife in  FIG. 1  shows the general assembly of the knife, which consists of the following main components: the blade  2 , scales  4  and  10 , the liners  6  and  8 , a spacer  14 , and the floating pivot  12 . The blade  2  includes a cutout  16  for a stone inset, a precision machine hole  20  for the floating pivot  12 , a machined face  22  where the locking mechanism  34  wedges, and a tang  18  to facilitate opening the blade. To open the knife, pressure is applied to the tang  18  of the blade  2 , providing a force which will rotate the blade on the floating pivot  12  into the open position. The first liner  6  has a precision hole  32  for the pivot mechanism  12 . The second liner  8  has the locking spring  34  cut into its body. This is then bent to provide the spring force for the locking mechanism. When fully opened, the locking bar  34  is forced against the locking face  22  of the blade, securing it in the open position; in doing so, the floating pivot  12  moves from one side of the knife to the other. The two scales  4  and  10  have precision holes  24  and  28  drilled into them for the floating pivot  12  as well as cutouts  26  and  30  for stone insets. The floating pivot  12  is precision machined in diameter and contains a precision notch to receive the locking mechanism  34 . The spacer  14  is cut to support the back of the knife and provide space for the blade between the sides of the knife Each side of the knife is assembled using small pins  36 ,  38 ,  40 ,  42 ,  44 ,  46 ,  48 ,  50 ,  54 ,  52 ,  56 , and  58  which are peened into place to attach the scale and liner together into a scale assembly; this includes scale  4  with liner  6 , and scale  8  with liner  10  respectively. The floating pivot  12  is inserted on the locking mechanism  34  with it extending through the hole  28 . To close the blade  2 , the extended portion of the floating pivot  12  is pressed, disengaging the locking bar  34  from its contact with the locking face  22 , allowing the blade  2  to be rotated on the floating pivot  12  to the closed position. To begin final assembly, first the blade is slid over the pivot  12  using the provided hole  20 . The spacer  14  is then set into place at the end of the knife. The other scale assembly is then placed over the floating pivot  12  using the provided holes  24  and  32 . Assembly is completed by inserting pins  60 ,  62 , and  64  in their appropriate holes and peening them into place. 
         [0012]    A cross sectional and end view of the floating pivot is shown in  FIG. 2   a , showing the location of the notch which is machined to provide mounting on the locking spring  34 .  FIG. 2   b  shows the floating pivot  12  attached to the locking spring  34 . 
         [0013]    A cross sectional view through the center of the floating pivot is shown in  FIG. 3 .  FIG. 3  a shows the floating pivot  12 , the scales  6  and  8 , the liners  4  and  10 , and the blade  2 . The locking liner  8  has the body and the locking mechanism in alignment, which will allow the blade  2  to pivot. In  FIG. 3  b, the floating pivot  8  is pushed to the opposite side, which moves the locking portion of  8  within the notch of the blade  2 , thus locking the blade in place in the open position. 
         [0014]    A view of the completed knife with the blade in the open position is shown in  FIG. 4 . Also in place are  2  stone insets  66  and  68 , which have been placed in the cutouts  16  and  26 . 
         [0015]    It will be obvious to those skilled in the art to make various changes, alterations and modifications to the invention described herein. To the extent such changes, alterations and modifications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.