Folding knife

[0001] This application claims priority based on Chinese Patent Application No. 200720183483.9 filed on Dec. 6, 2007 which is incorporated herein by reference.

[0002] The present invention relates to a folding knife.

[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'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.

[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.

[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.

[0031] Below, the first embodiment according to the present invention is described referring to FIG. 1A-FIG. 1E. 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. 1D, 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. 1C, 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. 1C 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.

[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. 2A.

[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. 1C.

[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.

[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. 3C.

[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. 1C.

[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.