Abstract:
The present invention provides a fold knife comprising a handle and a blade hinged to the handle. The fold knife further comprises a switch mechanism for manual and semi-automatic operation which is positioned in the inner chamber of the handle. The switch mechanism for manual and semi-automatic operation has a first position in which it is allowed to manually open the blade from the handle and a second position in which it is allowed to automatically open the blade from the handle. The fold knife according to the present invention is capable of easily switching between the manual operation condition and the semi-automatic operation condition by means of the switch mechanism for manual and semi-automatic operation, so as to satisfy various requirements of a user where, on one hand, it can guarantee the safety in use for the users such as a kid and on the other hand it can obtain the facilitation in the opening procedure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority based on Chinese Patent Application No. 200720183483.9 filed on Dec. 6, 2007 which is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a folding knife. 
       BACKGROUND OF THE INVENTION 
       [0003]    A fold knife has become a common tool in the daily life, bringing about great convenience for people. The existing folding knifes can be classified into a manual type fold knife and a semi-automatic type fold knife. Just as the name implies, the manual type fold knife needs to be operated by a user&#39;s hand throughout its whole opening procedure, whereas as for the semi-automatic fold knife, the user only needs to exert a force at the beginning stage of the opening while in the sequential stage the fold knife is automatically opened by means of a device inside the knife. 
         [0004]    It is appreciated from the above that since the user needs to operate the manual fold knife throughout the whole opening procedure, it needs a great effort to open it but on the other hand it is comparatively safe to use for the users such as kids. Contrarily, the semi-automatic fold knife can be facilitated in opening while degraded in terms of safety. As a result, there is a need of a fold knife capable of switching between the manual operation condition and the semi-automatic operation condition depending on the requirements of a user. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is made exactly for aiming to the above problems. The object of the present invention is to provide a fold knife which can meet various requirements, that is, it can be switched either into the manual operation condition under which it is comparatively safe for the user (such as a kid) to use or into the semi-automatic operation condition under which it is relatively facilitated during the opening. 
         [0006]    According to the present invention, it is provided a fold knife which comprises a handle and a blade hinged to the handle. The fold knife further comprises a switch mechanism for manual and semi-automatic operation which is positioned in the inner chamber of the handle and has a first position in which it is allowed to manually open the blade from the handle and a second position in which it is allowed to semi-automatically open the blade from the handle. 
         [0007]    Preferably, the switch mechanism for manual and semi-automatic operation includes: a resilient portion pivotally mounted in the handle; and a switch member provided on the handle with its one part exposed to the outside and has a first switch position in which the end of the resilient part adjacent to the blade slightly contacts the blade or is out of contact with it and a second switch position in which the switch member biases the resilient portion such that when the blade is closed, the end of the resilient portion presses against the corresponding end of the blade toward the open side of the handle so as to maintain the switch mechanism for manual and semi-automatic operation in the second position. 
         [0008]    Preferably, the switch member is a slider which is slidably connected to the handle by inserting the projections provided on the opposed sides of the slider into the corresponding slots of the handle respectively. 
         [0009]    Preferably, the switch member is a pin which is slidably connected to the handle by passing through the corresponding slot of the handle. 
         [0010]    Preferably, the switch member is provided on one side of the resilient portion opposed to the open side of the handle and provided between the pivot axis and the blade in the manner of approaching the pivot axis of the resilient portion. 
         [0011]    Preferably, the resilient portion has an extension part at one side of the pivot axis of the resilient portion opposed to the blade and the switch member is provided below the extension part. 
         [0012]    Preferably, at one of the first switch position and the second switch position, the resilient portion is provided with a recess capable of accommodating the switch member. 
         [0013]    Preferably, the resilient portion has an extension part at one side of the pivot axis of the resilient portion opposed to the blade with the tail tip of the extension part having a bending part toward the open side of the handle, and also the switch member is a cam assembly which comprises: a rotating wheel pivotally mounted on the handle with the pivot axis positioned below the extension part; and a first and second projections which form an angle with respect to the center of the rotating wheel wherein the angle is set such that when the switch mechanism for manual and semi-automatic operation is in the first position only the first projection contacts and presses against the extension part whereas when the switch mechanism for manual and semi-automatic operation is in the second position the second project contacts the bending part. 
         [0014]    Preferably, the resilient portion includes a tab which is pivotally mounted in the handle and a pre-pulling member which is at one end fixed to the handle and at the other end fixed to the tab and allows the end of the tab adjacent to the blade to have the trend of rotating away from the open side of the handle. 
         [0015]    Preferably, the pre-pulling member is a coil spring or spring string. 
         [0016]    The fold knife according to the present invention can easily switch between the manual operation condition and the semi-automatic operation condition by means of the switch mechanism for manual and semi-automatic operation, so as to satisfy various requirements of a user wherein it on one hand can guarantee the safety of the users such as a kid and on the other hand can provide the facilitation in the opening procedure. 
         [0017]    It should be appreciated that the above general description and the following detailed description are of exemplification and illustration. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The accompanying figures constituting a part of the present specification helps to make the present invention more understandable wherein the figures illustrate embodiments of the present invention and are used together with the specification for describing the principle of the present invention, in which 
           [0019]      FIG. 1A  is the fold knife according to the first embodiment of the invention wherein the fold knife is under the semi-automatic operation condition and the blade is closed inside the inner chamber of the handle; 
           [0020]      FIG. 1B  is the fold knife according to the first embodiment of the present invention wherein the fold knife is under the semi-automatic operation condition and the blade is semi-opened from the inside of the handle and furthermore the part of the handle on one side is removed for clarification; 
           [0021]      FIG. 1C  is the fold knife according to the first embodiment of the present invention wherein the fold knife is under the semi-automatic operation condition and the blade is fully opened from the inside of the handle and moreover the blade is automatically opened by the resilient force of the tab during the movement from the operation condition shown in  FIG. 1B  to the operation condition shown in  FIG. 1C ; 
           [0022]      FIG. 1D  is the fold knife according to the first embodiment of the present invention wherein the fold knife is under the manual operation condition and the blade is semi-opened from the inside of the handle; 
           [0023]      FIG. 1E  is the tab of the fold knife according to the first embodiment of the present invention; 
           [0024]      FIG. 2  is the fold knife according to the second embodiment of the present invention wherein the fold knife is under semi-automatic operation condition and the blade is fully opened from the inside of the handle; 
           [0025]      FIG. 2A  is the slider of the fold knife according to the second embodiment of the present invention; 
           [0026]      FIG. 3  is the fold knife according to the third embodiment of the present invention wherein the fold knife is under the semi-automatic operation condition and the blade is fully opened from the inside of the handle; 
           [0027]      FIG. 3A  is the front view of the cam assembly of the fold knife according to the third embodiment of the present invention; 
           [0028]      FIG. 3B  is the side view of the cam assembly of the fold knife according to the third embodiment of the present invention; and 
           [0029]      FIG. 3C  is the tab of the fold knife according to the third embodiment of the present invention. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0030]    Hereinafter, a detailed description is made to certain embodiments of the present invention in conjunction with the figures. In Figures, a same reference number denotes the same or corresponding component. 
       First Embodiment 
       [0031]    Below, the first embodiment according to the present invention is described referring to  FIG. 1A-FIG .  1 E. The fold knife  100  according to the present invention comprises a handle  10 , a blade  20  hinged to the handle  10 , and a switch mechanism for manual and semi-automatic operation  30  positioned in the inner chamber of the handle  10  and used for allowing the fold knife  100  to switch between the manual operation condition and the semi-automatic operation condition. 
         [0032]    As shown in  FIG. 1A-FIG .  1 D, the switch mechanism for manual and semi-automatic operation  30  comprises: a tab  31  pivotally mounted in the inner chamber of the handle  10  wherein an extension portion  312  is provided on one side of the pivot axis of the tab  31  opposed to the blade  20  and a recess  3123  is provided in the bottom side of the extension portion  312 , as shown in  FIG. 1E ; a spring string  33  which is at one end fixed to the handle  10  and at the other end fixed to the tab  31  and allows the end  311  of the tab  31  adjacent to the blade  20  to have the trend of rotating away from the open side of the handle; and a pin  343  which is provided below the extension portion  312  and passes through the corresponding slot  36  of the handle  10  so as to be slidably connected to the handle  10 . In addition, for the sake of the convenience in use, the pin  343  has a part exposed to the outside of the handle  10 . 
         [0033]    Referring to  FIG. 1D , when the pin  343  is located in the recess  3123 , the pin  343  does not press against the tab  31 . Herein, the tab  31  has the trend of rotating away from the open side of the handle  10  under the effect of the pulling force of the spring string  33 . As a result, when the blade  20  is closed, the end  311  of the tab  31  adjacent to the blade  20  slightly contacts the blade  20  or is out of contact with it, such that the tab  31  does not exert or exert little force on the blade  20 . Consequently, during the opening of the blade  20 , the tab  31  does not function as the assistant force, i.e., the fold knife  100  is under the manual operation condition. 
         [0034]    In addition, referring to  FIG. 1A-FIG .  1 C, when the pin  343  is slid away from the blade  20  until moving out of the recess  3123 , the pin  343  biases the tab  31 , such that when the blade  20  is closed, the end  311  of the tab  31  presses against the corresponding end of the blade  20  toward the open side of the handle  10 . Therefore, when the blade  20  is manually opened from the position shown in  FIG. 1A  to the position shown in  FIG. 1B , the blade  20  can be automatically opened up to the position shown in  FIG. 1C  by means of the resilient force of the tab  31 . That is, the fold knife  100  in  FIG. 1A-FIG .  1 C is under the semi-automatic operation condition. 
         [0035]    Obviously, the present embodiment is not limited to the above, for example, the pin  343  may be provided on one side of the tab  31  opposed to the open side of the handle  10  and provided between the pivot axis of the tab  31  and the blade  20  in the manner of approaching the pivot axis of the tab  31 , i.e., the pin  343  is located at the position of the slider  341  shown in  FIG. 2 . 
       Second Embodiment 
       [0036]    The second embodiment according to the present invention is substantially same as the first embodiment in construction except for the switch mechanism for manual and semi-automatic operation  30 . Therefore, only the different construction of the second embodiment from the first embodiment is described hereinafter. 
         [0037]    Next, the second embodiment according to the present invention is described in conjunction with  FIG. 2-FIG .  2 A. 
         [0038]    As shown in  FIG. 2 , the switch mechanism for manual and semi-automatic operation  30  includes a tab  31  which is pivotally mounted in the handle  10  and is provided with a recess  3111  in the vicinity of the pivot axis; a spring string  33  which is at one end fixed to the handle  10  and at the other end fixed to the tab  31  allowing the end  311  of the tab  31  adjacent to the blade  20  to have the trend of rotating away from the open of the handle  10 ; and a slider  341  which is provided on one side of the tab  31  opposed to the open side of the handle  10  and provided between the pivot axis of the tab  31  and the blade  20  in the manner of approaching the pivot axis of the tab  31 . Particularly, as shown in  FIG. 2A , the opposed sides of the slider are provided with projections  3411  and  3412  respectively wherein the projections  3411  and  3412  are inserted into the corresponding slots  36  of the handle  10  respectively, such that the slider  341  is slidably connected to the handle  10 . 
         [0039]    Furthermore, for the convenience in use, the slider  341  has a part exposed to the outside of the handle  10 . Preferably, the part of the slider  341  exposed to the outside of the handle  10  is provided thereon with a decorative pattern  3413  for enhancing the friction. 
         [0040]    When the slider  341  is located inside the recess  3111  the slider  341  does not apply pressure against the tab  31 . Herein, the tab  31  has the trend of rotating away from the open side of the handle  10  under the effect of the pulling force of the spring string  31 . Therefore when the blade  20  is closed, the end  311  of the tab  31  adjacent to the blade  20  slightly contacts the blade  20  or is out of contact with it, resulting in that the tab  31  exerts little pushing pressure on the blade  20 . Consequently, during the opening of the blade  20 , the tab  31  does not function as the assistant force, i.e. the fold knife is under the manual operation condition. This manual operation condition is similar to that shown in  FIG. 1D . 
         [0041]    In addition, as shown in  FIG. 2 , when the slider  341  is slid toward the blade  20  until moving out of the recess  3111 , the slider  341  biases the tab  31  such that when the blade  20  is closed, the end  311  of the resilient portions  31 ,  33  presses against the corresponding end of the blade  20  toward the open side of the handle  10 , and therefore during the opening of the blade  20 , the tab  31  functions as the assistant force, i.e. the fold knife  100  is under the semi-automatic operation condition. This semi-automatic operation condition is similar to that shown in  FIG. 1A-FIG .  1 C. 
         [0042]    Of course, the present embodiment is not limited to the above, for example, an extension part  312  is provided on one side of the pivot axis of the tab  31  opposed to the blade  20  and the slider  341  is provided below the extension portion  312 . Additionally, the spring string  33  may be replaced by a coil spring. 
       Third Embodiment 
       [0043]    The third embodiment according to the present invention is substantially same as the first embodiment in construction except for the switch mechanism for manual and semi-automatic operation  30 . Therefore, only the different construction of the third embodiment from the first embodiment is described hereinafter. 
         [0044]    Next, the third embodiment according to the present invention is described in conjunction with  FIG. 3-FIG .  3 C. 
         [0045]    The switch mechanism for manual and semi-automatic operation  30  includes a tab  31  which is pivotally mounted in the handle  10  wherein an extension portion  312  is provided on one side of pivot axis of the tab  31  opposed to the blade  20  and has at its tail tip a bending part  3122  toward the open side of the handle  10 , as shown in  FIG. 3C ; a spring string  33  which is at one end fixed to the handle  10  and at the other end fixed to the tab  31  allowing the end  311  of the tab  31  adjacent to the blade  20  to have the trend of rotating away from the open side of the handle  10 ; and a cam assembly  342 . 
         [0046]    As shown in  FIG. 3A  and  FIG. 3B , the cam assembly  342  comprises: a rotating wheel  35  pivotally mounted in the handle  10  with the pivot axis provided below the extension part  312 ; and a first projection  3421  and a second projection  3422  provided on the rotating wheel  35  wherein the first projection  3421  and the second projection  3422  form an angle with respect to the center O of the rotating wheel  35  and the angle is set such that when the switch mechanism for manual and semi-automatic operation  30  is in the first position (i.e., when the fold knife  100  is under the semi-automatic operation condition), only the first projection  3421  contacts and presses against the extension part  312  and when the switch mechanism for manual and semi-automatic operation  30  is in the second position (i.e., when the fold knife  100  is under the manual operation condition), the second projection  3422  contacts the bending part  3122 . In addition, in order to assure good contact, the first projection  3421  and the second projection  3422  are preferably designed as an elongated shape, as shown in  FIG. 3A . 
         [0047]    In addition, for convenience in use, the rotating wheel  35  has a part exposed to the outside of the handle  10 . Preferably, the part of the rotating wheel  35  exposed to the outside of the handle  10  is provided thereon with a decorative pattern enhancing the friction. 
         [0048]    When the second projection  3422  contacts the bending part  3122 , the cam assembly  342  is clamped down due to the contact between the second projection  3422  and the bending part  3122 , and at this time, the cam assembly  342  does not apply pressure against the tab  31 . Herein, tab  31  has the trend of rotating away from the open side of handle  10  under the effect of the pulling force of the spring string  33 , such that when the blade  20  is closed, the end  311  of the tab  31  adjacent to the blade  20  slightly contacts the blade  20  or is out of contact with it, resulting in that the tab  31  does not exert or exert little force on the blade  20 . Consequently, during the opening of the blade  20 , the tab  31  does not function as the assistant force, i.e. the fold knife  100  is under the manual operation condition. This manual operation condition is similar to that shown in  FIG. 1D . 
         [0049]    In addition, as shown in  FIG. 3 , when the rotating wheel  35  of the cam assembly  342  is rotating clockwise until the first projection  3421  contacts the extension part  312 , the first projection  3421  presses against the extension part  312  therefore biasing the tab  31 , such that when the blade  20  is closed, the end  311  of the tab  31  presses against the corresponding end of the blade  20  toward the open side of the handle  10 . Consequently, during the opening of the blade  20 , the tab  31  functions as the assistant force, i.e. the fold knife  100  is under the semi-automatic operation condition. This semi-automatic operation condition is similar to that shown in  FIG. 1A-FIG .  1 C. 
         [0050]    Of course, the present embodiment is not limited to the above, for example, the first projection  3421  and the second projection  3422  may be provided as an extruding cylinder shape and the spring string  33  may be replaced by a coil spring, and so on. 
         [0051]    Although the present invention has been described in conjunction with the figures and the preferable embodiments, it is obvious for those skilled in the art that various changes and variations can be made to the present invention without departing from the spirit and the scope of the present invention. All such changes and variations of the present invention are covered by the appended claims and the equivalent thereof.