Patent Publication Number: US-10759067-B2

Title: Folding knife configured for rapid assembly and disassembly

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/593,362, filed on May 12, 2017, which claims the benefit of Taiwan Patent Application No. 106111935, filed Apr. 10, 2017, now Taiwan Patent No. I642524. The prior applications are incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to folding knives and more particularly to one provided with an engaging plate so that a user can rapidly disassemble and reassemble the folding knife by operating the engaging plate. 
     BACKGROUND OF THE INVENTION 
     Commercially available folding knives are typically composed of a handle and a blade, wherein the blade is pivotally connected to the handle and can be rotated about the pivot joint in order to spin out of or be stored in the handle. Compact when folded up, this type of knives can be carried around with ease, and with the blade stored in the handle for enhanced safety. For those engaged in outdoor activities (e.g., divers), soldiers, the police, and so forth, folding knives are far more convenient than knives that are not foldable. 
     Generally speaking, a folding knife that has been used for quite a while tends to have dirt stuck in the handle as well as a blunt blade. To get rid of the dirt or detach the blade for sharpening. the folding knife must be disassembled. However, folding knives are rarely designed to be taken apart by their users. A folding knife is usually designed in such a way that the blade is pivotally connected between two plates, and that the plates are fastened together with screws or other elements to form the handle and to ensure stability of the folding knife during use. Indeed, such a design can prevent separation of the handle and the blade while the folding knife is being operated, but the same design also adds to the difficulty of disassembly and thus hinders maintenance of the folding knife. 
     To solve the aforesaid problem, many a structural improvement has been made to the conventional folding knives, as briefly described below. Referring to  FIGS. 1A-1D , the folding knife  1  is composed of two plates  11 A,  11 B; a blade  13 ; and an actuating portion  15 . One side of the plate  11 A is protrudingly provided with a pivotal connection post  111  at a position adjacent to one end of the plate  11 A. The pivotal connection post  111  is provided with a first block  113  on the top side. The portion between the first block  113  and the pivotal connection post  111  is reduced in diameter to form an engaging groove  1111 . The first block  113  is rectangular and is arranged in a tilted manner (see  FIG. 1C ). The blade  13  is formed with a pivotal connection hole  131  at a position adjacent to one end of the blade  13 . The pivotal connection post  111  extends into the pivotal connection hole  131  so that the blade  13  is rotatable about an axis defined by the pivotal connection post  111 . The actuating portion  15  has one end pivotally provided on the aforesaid side of the plate  11 A at a position adjacent to the opposite end of the plate  11 A. Moreover, the top side of the actuating portion  15  is protrudingly provided with a second block  151  at a position adjacent to the aforesaid end of the actuating portion  15 . The second block  151  is also rectangular and can rotate along with the actuating portion  15 , and the portion between the second block  151  and the actuating portion  15  is also reduced in diameter to form an engaging groove. The plate  11 B is formed with a first aperture  112  at a position adjacent to one end of the plate  11 B and a second aperture  114  at a position adjacent to the opposite end of the plate  11 B. The first aperture  112  and the second aperture  114  are both rectangular. In addition. the first aperture  112  matches the first block  113  in configuration, and the second aperture  114  matches the second block  151  in configuration. The inner wall portion of the plate  11 B that corresponds to the bottom of the first aperture  112  is protrudingly provided with an engaging block  1121 , and the inner wall portion of the plate  11 B that corresponds to the bottom of the second aperture  114  is protrudingly provided with another engaging block. 
     With continued reference to  FIGS. 1A-1D , the folding knife  1  can be put together by its user in the following manner. First, the plate  11 B is placed at a specific angle with respect to the plate  11 A such that the first aperture  112  corresponds to the first block  113  (see  FIG. 1B ). Then, the actuating portion  15  is rotated to bring the second block  151  to the orientation shown in  FIG. 1B . After that, the first block  113  is inserted through the first aperture  112 , and with the engaging block  1121  corresponding to the engaging groove  1111  of the pivotal connection post  111 , the plate  11 B is rotated so that the second aperture  114  corresponds to the second block  151 . The second block  151  is then inserted through the second aperture  114 , and with the other engaging block on the plate  11 B corresponding to the engaging groove of the actuating portion  15 , the actuating portion  15  is rotated again. Consequently, the first block  113  and the second block  151  no longer correspond to the first aperture  112  and the second aperture  114  respectively (see  FIG. 1A ), and the engaging block  1121  and the other engaging block of the plate  11 B are respectively engaged with the blocks  113  and  151 . By the same token, the first thing to be done to dismantle the folding knife  1  is to rotate the actuating portion  15  so that the second block  151  corresponds to the second aperture  114 . Following that, the plate  11 B is rotated until the first aperture  112  corresponds to the first block  113 , and only then can the plate  11 B and the blade  13  be sequentially detached, allowing individual components to be cleaned or the blade  13  to be replaced. 
     While the folding knife described above is configured to be disassembled and reassembled by its user, the following problems are expected to arise in practical use: 
     (1) When disassembling or reassembling the folding knife, the user must adjust the positions of the plates, the blocks, and the actuating portion by turns repeatedly, which complicates the disassembly and reassembly procedures greatly. 
     (2) With the blocks and the apertures having specific shapes, the user has to adjust the positions of the blocks and the apertures carefully, for each block cannot extend through the corresponding aperture unless the former corresponds to the latter. Positional adjustment of the blocks and the apertures, however, is extremely time-consuming. 
     (3) The thickness of each engaging block must be equal to or slightly smaller than the height of the corresponding engaging groove in order for each engaging block to engage with the corresponding block after the plate to be operated (i.e., the plate  11 B) and the actuating portion are rotated. To this end, it is imperative to control the tolerances of the aforesaid thicknesses and heights within a very small range, or the folding knife will have problem being assembled (meaning the yield of the folding knife will be lowered). 
     (4) As the blocks are bound to collide respectively with the peripheries of the corresponding apertures when the user disassembles or reassembles the folding knife, the edges of the blocks or of the apertures may be damaged or deformed over time. Should the damage or deformation be severe, engagement between the blocks and their respective apertures will be made impossible, thus hampering normal use of the folding knife. 
     (5) While each block and the corresponding aperture must be adjusted to corresponding positions in order for the former to pass through the latter, it is difficult to align each block with the corresponding aperture when the folding knife is small, for in that case the blocks and the apertures will also be small. In other words, a reduction in size of the folding knife will add to the difficulty of assembly. 
     According to the above, the conventional folding knives still leave much to be desired. It is therefore a pressing issue for folding knife designers and manufacturers to develop a novel folding knife whose structural simplicity brings about greater convenience and safety of use. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the fact that the conventional folding knives fail to satisfy every user need, the inventor of the present invention incorporated years of practical experience as well as the spirit of continual improvement into extensive research and repeated trials and finally succeeded in developing a folding knife configured for rapid assembly and disassembly. The invention is intended to provide the general public with a more convenient and safer folding knife than those commercially available. 
     It is an objective of the present invention to provide a folding knife configured for rapid assembly and disassembly. The folding knife includes a blade and a handle. The handle is assembled from a first handle portion, a second handle portion, an engaging plate, and a switch. The blade is formed with a pivotal connection hole at a position both adjacent to one end of the blade and distant from the tip of the blade. The inner side of the first handle portion is connected to one end of a first engaging post and one end of a second engaging post at positions respectively adjacent to two opposite ends of the first handle portion. The opposite, or second, end of each of the engaging posts is circumferentially provided with an engaging groove. The first engaging post extends through the pivotal connection hole of the blade to pivotally connect the blade to the first handle portion so that the blade can be rotated about an axis defined by the first engaging post. The second handle portion is provided therein with a receiving space. The inner side of the second handle portion is formed with a first engaging hole at a position adjacent to one end of the second handle portion and is formed with a second engaging hole at a position adjacent to the opposite end of the second handle portion. The outer side of the second handle portion is formed with a switch hole. The first engaging hole, the second engaging hole, and the switch hole are in communication with the receiving space. When the second handle portion is assembled to the first handle portion, the second end of the first engaging post extends through the first engaging hole into the receiving space, and the second end of the second engaging post extends through the second engaging hole into the receiving space. The engaging plate is mounted in the receiving space and can be displaced toward either of two opposite ends of the receiving space. The engaging plate is provided with a first engaging portion and a second engaging portion at positions respectively adjacent to two opposite ends of the engaging plate. The first engaging portion matches the first engaging groove in configuration, and the second engaging portion matches the second engaging groove in configuration. The switch extends into and is received in the switch hole and can be displaced toward either of two opposite ends of the switch hole. The inner side of the switch is connected to the engaging plate while the outer side of the switch is exposed through the switch hole. When pushed and thereby displaced toward one of the two opposite ends of the switch hole, the switch displaces the engaging plate toward one of the two opposite ends of the receiving space, thus disengaging the first engaging portion from the first engaging groove and the second engaging portion from the second engaging groove, allowing the first handle portion, the second handle portion, and the blade to be detached from one another. When pushed and thereby displaced to the other of the two opposite ends of the switch hole, the switch displaces the engaging plate toward the other of the two opposite ends of the receiving space, thus bringing the first engaging portion into engagement with the first engaging groove and the second engaging portion into engagement with the second engaging groove. As a result, the first handle portion and the second handle portion are coupled together to form the handle, and the blade can be rotated about the axis defined by the first engaging post in order to store the cutting edge of the blade in the handle or rotate the cutting edge of the blade out of the handle. As a user only has to push the switch in order for the engaging plate to engage with or disengage from the engaging grooves and thereby bring the first handle portion and the second handle portion into a coupled or detachable state, the folding knife can be cleaned with great ease. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The above and other objectives, as well as the technical features and effects, of the present invention can be better understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which: 
         FIG. 1A  shows a conventional folding knife in a certain state; 
         FIG. 1B  shows the conventional folding, knife in  FIG. 1  in another state; 
         FIG. 1C  shows the conventional folding knife in  FIG. 1  in still another state; 
         FIG. 1D  is a partial sectional view of the two plates of the conventional folding knife in  FIG. 1 ; 
         FIG. 2  is an assembled perspective view of a folding knife according to the present invention; 
         FIG. 3  is an exploded perspective view of the folding knife in  FIG. 2 ; 
         FIG. 4  is a sectional view of the folding knife in  FIG. 2 ; 
         FIG. 5  is a perspective view showing the engaging plate and the engaging posts of the folding knife in  FIG. 2  in a certain state; 
         FIG. 6  is a perspective view showing the engaging plate and the engaging posts of the folding knife in  FIG. 2  in another state; and 
         FIG. 7  is a partial sectional view of the switch of the folding knife in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides a folding knife that can be rapidly assembled and disassembled. In one embodiment, referring to  FIGS. 2 ˜ 4 , the folding knife is assembled at least from a blade  20 A and a handle  20 B. The blade  20 A is formed with a pivotal connection hole  202  at a position both adjacent to one end of the blade  20 A and distant from the tip  201 . In addition, the side of the blade  20 A that is adjacent to the pivotal connection hole  202  and faces away from the cutting edge  203  is protrudingly provided with a pushing post  204 . Once the blade  20 A and the handle  20 B are put together, the pushing post  204  is exposed from the handle  20 B so that one who is holding the folding knife can rotate the blade  20 A out of the handle  20 B by pushing the pushing post  204  with a finger. 
     With continued reference to  FIGS. 2 ˜ 4 , the handle  20 B includes a first handle portion  21  and a second handle portion  22 . The inner side of the first handle portion  21  is protrudingly provided with a first engaging post  211  at a position adjacent to one end of the first handle portion  21  and is protrudingly provided with a second engaging post  212  at a position adjacent to the opposite end of the first handle portion  21 . In this embodiment, the first engaging post  211  and the second engaging post  212  are independent components, each configured to be fixed to the inner side of the first handle portion  21  at one end. Moreover, the opposite end (hereinafter referred to as the second end) of the first engaging post  211  is circumferentially provided with a first engaging groove  2113  while the opposite end (hereinafter referred to as the second end) of the second engaging post  212  is circumferentially provided with a second engaging groove  2123 . In other embodiments of the present invention, the first engaging post  211  and the second engaging post  212  may be integrally formed with the first handle portion  21  instead to meet production or design requirements, e.g., to reduce the number of components. 
     Referring again to  FIGS. 2 ˜ 4 , the second handle portion  22  is formed therein with a receiving space  220 . The inner side of the second handle portion  22  is formed with a first engaging hole  221  at a position adjacent to one end of the second handle portion  22  and is formed with a second engaging hole  222  at a position adjacent to the opposite end (hereinafter referred to as the second end) of the second handle portion  22 . In addition, the outer side of the second handle portion  22  is formed with a switch hole  223 . The first engaging hole  221 , the second engaging hole  222 , and the switch hole  223  are in communication with the receiving space  220 . In this embodiment, the second handle portion  22  is assembled from an inner part  22 A and an outer part  22 B, the receiving space  220  is formed between the inner part  22 A and the outer part  22 B, the first engaging hole  221  and the second engaging hole  222  are provided at two opposite ends of the inner part  22 A respectively, and the switch hole  223  is provided in the outer part  22 B. In other embodiments of the present invention, the structure of the second handle portion  22  may be adjusted as appropriate to include a single one component or multiple components, provided that the second handle portion  22  has the foregoing structural features. Besides, an engaging plate  23  is mounted in the receiving space  220  of the second handle portion  22 . The engaging plate  23  can be displaced toward either of two opposite ends of the receiving space  220  and is formed with a first engaging portion  231  at a position adjacent to one end of the engaging plate  23  and a second engaging portion  232  at a position adjacent to the opposite end of the engaging plate  23 . The first engaging portion  231  matches the first engaging groove  2113  in configuration and can be engaged in the first engaging groove  2113 . The second engaging portion  232  matches the second engaging groove  2123  in configuration and can be engaged in the second engaging groove  2123 . 
     As shown in  FIGS. 2 ˜ 4 , the second handle portion  22  is mounted with a switch  30 . The switch  30  extends into and is received in the switch hole  223  and can be displaced toward either of two opposite ends of the switch hole  223 . The inner side of the switch  30  is connected to the engaging plate  23  in order for the switch  30  to drive the engaging plate  23  into displacement. The outer side of the switch  30  is exposed through the switch hole  223  so that a user can push the switch  30  with a finger, thereby displacing the engaging plate  23  toward either a first end or an opposite second end of the receiving space  220 . Once the blade  20 A is pivotally connected to the first handle portion  21  by inserting the first engaging post  211  through the pivotal connection hole  202  of the blade  20 A, and the second handle portion  22  is assembled to the first handle portion  21  by inserting the second ends of the first engaging post  211  and of the second engaging post  212  into the first engaging hole  221  and the second engaging hole  222  respectively, the user can bring the first engaging portion  231  and the second engaging portion  232  of the engaging plate  23  respectively into engagement in the first engaging groove  2113  and the second engaging groove  2123  of the engaging plate  23  (see  FIG. 5 ) simply by pushing the switch  30  with a finger and thus displacing the engaging plate  23  toward the second end of the receiving space  220  (e.g., rightward as shown in  FIG. 4 ). Thus, the first handle portion  21  and the second handle portion  22  are rapidly and securely coupled to each other to form the handle  20 B, with the engaging portions  231 ,  232  restricted respectively by the engaging grooves  2113 ,  2123  to prevent the first handle portion  21  and the second handle portion  22  from separating from each other. The blade  20 A can now be rotated about its pivot shaft (i.e. the first engaging post  211 ) in order to store the cutting edge  203  between the first handle portion  21  and the second handle portion  22 , leaving only the pushing post  204  outside the handle  20 B (see  FIG. 2 ). In this embodiment, the switch  30  is located on one side of the second handle portion  22  and is adjacent to the second end of the second handle portion  22 , the engaging plate  23  is formed with an engaging hole  234 , and the switch  30  is assembled to the engaging plate  23  by having the inner side of the switch  30  engaged in the engaging hole  234 . In practice, however, the way the switch  30  and the engaging plate  23  are assembled together may be adjusted according to product requirements. The position of the switch hole  223  may also be adjusted so that the switch  30  is located elsewhere on the second handle portion  22 , as long as the switch  30  can be used to displace the engaging plate  23 . 
     Referring again to  FIGS. 2 ˜ 4 , when it is desired to disassemble the folding knife in order to get rid of the dirt therein, the user only has to push the switch  30  with a finger and thereby displace the engaging plate  23  toward the first end of the receiving space  220  (e.g., leftward as shown in  FIG. 4 ), and the first engaging portion  231  and the second engaging portion  232  of the engaging plate  23  will be disengaged respectively from the first engaging groove  2113  and the second engaging groove  2123  at the same time (see  FIG. 6 ). Once the engaging portions  231 ,  232  are no longer engaged in the engaging grooves  2113 ,  2123  respectively, the user can detach the second handle portion  22  and the blade  20 A sequentially from the first handle portion  21  in order to clean the folding, knife or replace the blade  20 A with a new one. The structure of the folding knife of the present invention is so designed that, simply by pushing the switch  30 , the user can render the folding knife rapidly but surely into a state where disassembly is allowed (see  FIG. 6 ) or a state where disassembly is prevented (see  FIG. 5 ). Now that the complicated steps required to disassemble and reassemble the conventional folding knives are no more necessary, the folding knife of the present invention features greater convenience of use. Furthermore, in contrast to the conventional folding knives (e.g., the folding knife  1  described in Description of Related Art, whose users have to adjust the positions of the blocks and the apertures carefully), the folding knife of the present invention allows the engaging plate  23  to be adjusted in position (to either engage with or disengage from the engaging posts  211 .  212 ) by no more than a push on the switch  30 . 
     In another embodiment of the present invention, referring again to  FIGS. 2 ˜ 4 , the folding knife further includes an elastic plate  24  mounted between the first handle portion  21  and the second handle portion  22 . The elastic plate  24  is formed with a first through hole  241  at a position adjacent to one end of the elastic plate  24  and is formed with a second through hole  242  at a position adjacent to the opposite end of the elastic plate  24  so that the first engaging post  211  can pass through the first through hole  241  into the first engaging hole  221  while the second engaging post  212  passes through the second through hole  242  into the second engaging hole  222 . The elastic plate  24  is further provided with a stopping portion  243 . When the blade  20 A has been rotated completely out of the handle  20 B, the stopping portion  243  is engaged with the aforesaid end of the blade  20 A such that the blade  20 A cannot be rotated into the handle  20 B. Only when the stopping portion  243  is forced out of engagement with the blade  20 A can the blade  20 A be rotated again and thereby stored in the handle  20 B. While the stopping portion  243  is depicted in the drawings as a plate, it is feasible in another embodiment of the present invention to configure the stopping portion  243  otherwise (e.g., as a protuberance), and in that case, the aforesaid end of the blade  20 A will be provided with a groove corresponding in position to the protuberance in order to engage with the protuberance. 
     To prevent excessive rotation of the blade  20 A, referring to  FIGS. 3 and 4 , the blade  20 A in still another embodiment of the present invention is formed with a curved position-limiting groove  205  at a position adjacent to the aforesaid end of the blade  20 A while the handle  20 B is provided therein with a position-limiting post  25 . In this embodiment, the position-limiting post  25  extends through the position-limiting groove  205  and has two opposite ends connected respectively to the inner side of the first handle portion  21  and the inner side of the second handle portion  22 . The position of the position-limiting post  25  within the position-limiting groove  205  is changed when the blade  20 A is rotated. For example, when the blade  20 A has been rotated completely out of the handle  20 B, the position-limiting post  25  is pressed against the wall of one end of the position-limiting groove  205 . When the blade  20 A is subsequently rotated to be stored in the handle  20 B, the position of the position-limiting post  25  in the position-limiting groove  205  is gradually changed. Once the blade  20 A is entirely stored in the handle  20 B, the position-limiting post  25  is pressed against the wall of the opposite end of the position-limiting groove  205 . Thus, by adjusting the length of the position-limiting groove  205 , it can be ensured that the blade  20 A will be kept securely at the predetermined terminal positions, without fear that a user may rotate the blade  20 A excessively. It should be pointed out that, when the folding knife includes the elastic plate  24 , the position-limiting post  25  extends through the elastic plate  24  (see  FIG. 4 ). 
     In yet another embodiment of the present invention, referring, to  FIG. 3  and  FIG. 7 , the bottom side of the switch  30  is formed with a recess  300 . The recess  300  is mounted therein, from the inside out, with a spring  301  and a ball  303 . In addition, the inner side of the second handle portion  22  is concavely provided with a first positioning hole  225  and a second positioning hole  227 , both corresponding in position to the switch hole  223 . In this embodiment, the first positioning hole  225  and the second positioning hole  227  are provided in the inner side of the inner part  22 A at positions corresponding to the switch hole  223 . When the switch  30  has been pushed and thereby displaced to one end of the switch hole  223 , the ball  303  corresponds to the first positioning hole  225  and is pushed by the spring  301  into engagement in the first positioning hole  225 , thereby securing the switch  30  in place. In the course in which the switch  30  is pushed and thereby displaced in the opposite direction, the ball  303  is forced to push the spring  301  further into the recess  300 . Once the switch  30  reaches the opposite end of the switch hole  223 , the ball  303  corresponds to the second positioning hole  227  and is pushed by the spring  301  into engagement in the second positioning hole  227 , thereby securing the switch  30  where it is. The switch  30 , therefore, cannot be displaced without being pushed by a force that can overcome the force applied by the spring  301  to the ball  303 . This technical feature allows the folding knife to be placed safely in a bag or pocket because the switch  30  will not be displaced, let alone allow separation of the blade  20 A and the handle  20 B, even when accidentally pushed by an object in the bag or pocket. 
     The above-mentioned descriptions represent merely the exemplary embodiment of the present disclosure, without any intention to limit the scope of the present disclosure thereto. Various equivalent changes, alternations or modifications based on the claims of present disclosure are all consequently viewed as being embraced by the scope of the present disclosure.