Patent Publication Number: US-11034035-B2

Title: Utility knife

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a utility knife. 
     Description of the Prior Art 
     Generally, a utility knife includes a housing, a blade carrier slidably disposed within the housing and a blade assembled to the blade carrier. The blade of the utility knife is trapezoid and has two cutting edges disposed at two opposite sides. When one of the two cutting edges is blunted or damaged, the blade is flipped to use the other of the two cutting edges or replaced by another blade. 
     However, the utility knife disclosed in TWI309197, for example, the blade carrier and the blade of a conventional utility knife are disposed between two housing members which are screwed to each other. Therefore, the two housing members have to be separated from each other to flip or replace the blade, which is inconvenient to assemble, disassemble and replace. 
     The present invention is, therefore, arisen to obviate or at least mitigate the above-mentioned disadvantages. 
     SUMMARY OF THE INVENTION 
     The main object of the present invention is to provide a utility knife with its blade quickly and safely replaceable. 
     To achieve the above and other objects, the present invention provides a utility knife, including: a first housing, a second housing, a blade carrier and a locking mechanism. The first housing includes a shaft disposed thereon and having an axis. The second housing is rotatably mounted to the shaft and includes a first engaging portion. The blade carrier is movably received between the first housing and the second housing, and is operable, from an outside of the first housing and the second housing, to move. The locking mechanism is disposed through the second housing and is non-rotatable relative to the shaft. The locking mechanism is axially slidable between a locking position and a releasing position along the shaft and rotatable about the axis. The locking mechanism includes a pressing end which is operable, from the outside of the first housing and the second housing, to move axially and an engaging end which is comovable with the pressing end. The engaging end includes a second engaging portion. One of the first engaging portion and the second engaging portion includes at least one engaging concave, and the other of the first engaging portion and the second engaging portion includes at least one projection which is releasably engageable with the at least one engaging concave. One of the at least one engaging concave and the at least one projection includes a first inclined surface which is tilted relative to the axis, and the other of the at least one engaging concave and the at least one projection includes an abutting portion which is abuttable against the first inclined surface. When the locking mechanism is in the locking position and the at least one projection is engaged within the at least one engaging concave, the second housing is non-rotatable relative to the first housing; when the locking mechanism is in the releasing position, the at least one projection is disengaged from the at least one engaging concave and the second housing is rotatable about the locking mechanism and rotatable relative to the first housing. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment(s) in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a stereogram of a preferable embodiment of the present invention; 
         FIG. 2  is a breakdown drawing of a preferable embodiment of the present invention; 
         FIG. 3  is another breakdown drawing of a preferable embodiment of the present invention; 
         FIG. 4  is a side view of a preferable embodiment of the present invention; 
         FIG. 5  is a schematic diagram of a preferable embodiment of the present invention in operation; 
         FIG. 6  is a partial schematic diagram of a preferable embodiment of the present invention; 
         FIG. 7  is a partial cross-sectional view of a preferable embodiment of the present invention; 
         FIG. 8  is another partial schematic diagram of a preferable embodiment of the present invention; 
         FIGS. 9 to 11  are schematic diagrams of configurations of a blade carrier and housings of a preferable embodiment of the present invention; 
         FIGS. 12 to 13  are cross-sectional views taken along line A-A of  FIG. 4 ; 
         FIG. 14  is a cross-sectional view taken along line B-B of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIGS. 1 to 14  for a preferable embodiment of the present invention. A utility knife  1  of the present invention includes a first housing  10 , a second housing  20 , a blade carrier  30  and a locking mechanism  40 . 
     The first housing  10  includes a shaft  11  disposed thereon and having an axis  111 . The second housing  20  is rotatably mounted to the shaft  11  and includes a first engaging portion  21 . The blade carrier  30  is movably received between the first housing  10  and the second housing  20 , and the blade carrier  30  is operable, from an outside of the first housing  10  and the second housing  20 , to move. The locking mechanism  40  is disposed through the second housing  20  and is non-rotatable relative to the shaft  11 . The locking mechanism  40  is preferably coaxial with the shaft  11 , and the locking mechanism  40  is axially slidable between a locking position (as shown in  FIGS. 7 and 12 ) and a releasing position (as shown in  FIG. 13 ) along the shaft  11 . The locking mechanism  40  includes a pressing end  41  which is operable, from outside of the second housing  20 , to move axially and an engaging end  42  which is comovable with the pressing end  41 . The engaging end  42  includes a second engaging portion  421 . One of the first engaging portion  21  and the second engaging portion  421  includes at least one engaging concave  211 , and the other of the first engaging portion  21  and the second engaging portion  421  includes at least one projection  422  which is releasably engageable with the at least one engaging concave  211 . One of the at least one engaging concave  211  and the at least one projection  422  includes a first inclined surface  423  which is tilted relative to the axis  111 , and the other of the at least one engaging concave  211  and the at least one projection  422  includes an abutting portion  212  which is abuttable against the first inclined surface  423  for stable engagement. However, the engaging concave and the projection may be configured to have no inclined surface. When the locking mechanism  40  is in the locking position and the at least one projection  422  is engaged within the at least one engaging concave  211 , the second housing  20  is non-rotatable relative to the first housing  10 ; when the locking mechanism  40  is in the releasing position, the at least one projection  422  is disengaged from the at least one engaging concave  211  and the second housing  20  is rotatable about the locking mechanism  40  and rotatable relative to the first housing  10  (as shown in  FIGS. 5 and 13 ). Therefore, a blade  100  of the utility knife  1  can be quickly and safely replaced. 
     One of the pressing end  41  and the engaging end  42  includes at least one engaging hole  411 , and the other of the pressing end  41  and the engaging end  42  includes at least one engaging arm  424  engaged with the at least one engaging hole  411 . Preferably, the second housing  20  further includes at least one guiding slot  213  extending about the axis  111 , and the at least one engaging arm  424  is rotatable about the axis  111  and disposed through the at least one guiding slot  213 . Each of the at least one guiding slot  213  includes a broadened segment  214  which is broaden radially and outwardly so as to be convenient for the engaging arm  424  to dispose therethrough. In this embodiment, a circumferential wall of the pressing end  41  includes two of said engaging holes  411 , the engaging end  42  includes two of said the engaging arms  424 , a distal end of each of the two of said engaging arms  424  includes a hooked portion  425 , and the second housing  20  includes two of said guiding slots  213 . Each of the two of said engaging arms  424  penetrates through one of the two of said guiding slots  213  and is connected with one of the two of said engaging holes  411  by the hooked portion  425  (as shown in  FIGS. 6 and 8 ). The second housing  20  is stably rotatable about the two of said engaging arms  424  by the two of said guiding slots  213 . 
     In this embodiment, the second housing  20  has the at least one projection  422 , and the engaging end  42  has the at least one engaging concave  211 . The at least one projection  422  includes a plurality of ribs  426  extending radially, and the at least one engaging concave  211  includes a plurality of grooves  215  which extend radially and are releasably engageable with the plurality of ribs  426  so as to achieve stable engagement and multi-step positioning. In other embodiments, the at least one projection may have only one of said rib and the at least one engaging concave may include a plurality of grooves. The abutting portion  212  includes a second inclined surface  216  which is abuttable against the first inclined surface  423 . Gradients of the first inclined surface  423  and the second inclined surface  216  relative to the axis  111  are substantially the same, and a depth of the engaging concave  211  is larger than a height of the projection  422  (as shown in  FIG. 7 ); however, the gradients of the first inclined surface and the second inclined surface relative to the axis may be different from each other. Therefore, the first inclined surface  423  and the second inclined surface  216  are stably abutted against each other. The locking mechanism  40  further includes an elastic member  43  which is sleeved to the shaft  11  and elastically abutted against and between the first housing  10  and the engaging end  42  so that the abutting portion  212  is stably abutted against the first inclined surface  423 . 
     One of the first housing  10  and the second housing  20  includes at least one elastic engaging member  50 , and the other of the first housing  10  and the second housing  20  includes at least one recession  51  within which is releasably engageable with the at least one elastic engaging member  50 . One of the first housing  10  and the second housing  20  further includes at least one through hole  52  in which the at least one elastic engaging member  50  is received and a lid member  53  which covers the at least one through hole  52 . In this embodiment, the first housing  10  has the through hole  52 , and an engaging member  54  and a resilient member  55  of the at least one elastic engaging member  50  are easy to be installed into the through hole and covered by the lid member  53  (as shown in  FIG. 14 ), without additional process of narrowing the opening of the through hole. The second housing  20  further includes a channel  22 , and the blade carrier  30  includes a restricting member  31  extending in a direction toward the second housing  20  and movable into or out of the channel  22  (as shown in  FIGS. 10 and 11 ). The blade carrier  30  is movable between a protruding position and a retracting position relative to the first housing  10 . When the blade carrier  30  is in the retracting position (as shown in  FIG. 10 ), the restricting member  31  is located out of the channel  22  and free of interference with the second housing  20  in a rotational direction of the second housing  20 , and the second housing  20  is rotatable about the locking mechanism  40  and rotatable relative to the first housing  10  when the locking mechanism  40  is in the releasing position; when the blade carrier  30  is moved toward the protruding position (as shown in  FIG. 11 ), the restricting member  31  is moved into the channel  22  and the second housing  20  is non-rotatable relative to the first housing  10 . For safety, the second housing  20  is rotatable only when the blade  100  is entirely retracted. 
     Preferably, the first housing  10  further includes a magnetically attractable member  60  (as shown in  FIGS. 2 and 3 ), and the magnetically attractable member  60  and the blade carrier  30  are magnetically attractable to each other. At least one of the magnetically attractable member  60  and the blade carrier  30  has magnetism. For example, the magnetically attractable member  60  is a magnet, and the blade carrier  30  includes magnetically attractable metal material. Therefore, the blade carrier  30  is magnetically attractable by the magnetically attractable member  60  and the blade carrier  30  can be held on the first housing  10  during removement of the blade  100  from the blade carrier  30 . One of the first housing  10  and the second housing  20  preferably include a blocking edge  12  which is blockable with the other of the first housing  10  and the second housing  20  so as to ensure closed positions of the first housing  10  and the second housing  20 . Preferably, the other of the first housing  10  and the second housing  20  includes a notch  23  or inner blocking shoulder for stopping the blocking edge  12  (as shown in  FIG. 2 ) so as to have a smooth appearance. 
     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.