Abstract:
A self-loading utility knife including an elongate handle having an internal chamber defining an axis and at one end is flat aperture for the passage of an active blade. The flat aperture defines a cutting plane extending through said handle along the axis. A blade-holder is slidably mounted in the chamber for movements in directions along the axis and is adapted to secure a single active blade for movement through the aperture when the blade holder is in the extended position. A blade-holder release button is coupled to the blade holder and is slidingly movable relative to the handle to move blade holder between retracted and extended positions. The handle has a blade compartment which is open to the chamber and can receive a stack of spare blades when a cover to the compartment is opened and blades can be shifted transversely relative to the axis into the chamber. The blade holder is provided with a recess having a depth no greater than the thickness of one blade to allow at least a portion of a single blade to be received in a retaining relationship within the recess to cause an end-most blade in the stack to be received within said recess to follow the movements of the blade holder. A spring biases the blades in the blade compartment inwardly in the direction of the blade holder. A blade releasing disc on the blade holder selectively locks a blade to the blade holder when the blade holder is in the extended position. The blade holder only receives a single blade within the recess. A belt clip s provided on the compartment cover.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 12/773,283, filed May 4, 2010, which claims benefit of U.S. provisional patent application Ser. No. 61/175,234, filed May 4, 2009. Each of the aforementioned related patent applications is herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention generally related to a hand tools, and more specifically to a self loading utility knife with a quick release blade mechanism. 
         [0004]    2. Description of the Related Art 
         [0005]    Conventional utility knives have various types of structures including fixed, foldable and retractable. They are generally used to cut paper, fabric, and leather. The Chinese Patent Application No. 93208241.6 (Publication Date: Jun. 22, 1994) disclosed “a retractable rope-cut utility knife”, in which a blade stored in a handle is extended out step by step by moving a slider. However, it is not convenient to replace the blade. The Chinese Patent Application No. 03223149.0 (Publication Date: Dec. 24, 2003) disclosed “a combined utility knife”. It is convenient to replace a blade by arranging the blade in a groove of the handle assembly and using a top cover in connection with a lock member. However, the following problems exist. The structure is complex; when replacing a blade, a user needs to release the lock member first and then rotate the top cover, which is complicated and inconvenient. The Chinese Patent Application No. 20042010202117.2 (Publication Date: Feb. 8, 2006) disclosed “a utility knife” in which a blade is arranged in a mounting groove of a handle assembly and a fixing hole is provided in the handle assembly. A bolt anchored in the fixing hole secures the blade. This utility knife is also disadvantageous because extra tools are used when the blade is replaced. 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly, it is an object of the invention to provide a retractable utility knife that is self loading, that does not include the disadvantages inherent in prior art utility knives. 
         [0007]    It is another object of the invention to provide a retractable self loading utility knife that is simple in construction and economical to manufacture. 
         [0008]    It is still another object of the invention to provide a retractable self loading utility knife as in the previous objects which permits one hand operation for releasing a blade from the knife. 
         [0009]    It is yet another object of the invention to provide a retractable self loading utility knife of the type under discussion that is easy and convenient to use. 
         [0010]    It is a further object of the invention to provide a retractable self loading utility knife as suggested in the previous objects that is ergonomically configured to allow a blade to be released with the thumb of a user while the blade is being held in the same hand of the user. 
         [0011]    It is still a further object of the invention to provide a self loading utility knife as in the previous objects that is easy to load with a supply of blades. 
         [0012]    It is yet a further object of the invention to provide a utility knife the previous objects that includes a safety mechanism for preventing inadvertent movement of the carriage and, therefore, the blade mounted on it, to the extended operative and exposed position. 
         [0013]    It is yet a further object of the invention to provide a utility knife that is self loading and includes an access panel to the blades storage compartment that also serves as a panel that is integrally formed with a spring clip for attaching the utility knife on a belt or the like. 
         [0014]    It is an additional object of the invention to provide the utility knife as in the previous objects that provides a smooth operation, includes a quick release blade mechanism that is only accessible when the blade supporting carriage is in its extended position thereby concealing the blade release mechanism in the retracted position of the carriage so that the blade cannot be inadvertently released. 
         [0015]    It is yet an additional object of the invention to provide a utility knife wherein the blade is released with a side-mounted, sliding member that permits a user to release a blade without the necessity of manipulating a top mounted release member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    Other objects and features of the present invention may become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which: 
           [0017]      FIG. 1  is a front perspective view of the self loading utility knife in accordance with the invention, showing the blade-supporting carriage in its forward extended position to expose the blade as during its normal use; 
           [0018]      FIG. 2  (A) is a side elevational view of the utility knife showing  FIG. 1 , showing partially broken way to illustrate the internal carriage and supported blade; the retracted locked position of the carriage; 
           [0019]      FIG. 2  (B) is similar to  FIG. 2  (A) but showing the locked carriage moved to the extended position exposing the quick release blade mechanism; 
           [0020]      FIG. 3  (A) is a fragmented view of the reverse side of the carriage shown in  FIGS. 2(A)  and  FIG. 2(B) , illustrating the tab which is integrally formed with the blade release disc in the manner in which it engages a notch in a blade; 
           [0021]      FIG. 3  (B) is similar to  FIG. 3  (A), but illustrating the manner in which the blade release disc is rotated to raise the tab  42   c  to clear the notch in the blade and the manner in which the blade is released; 
           [0022]      FIG. 4  is a exploded perspective view illustrating the manner in which the clip cover also used to close the blade storage or reservoir is opened for adding additional blades that become available for self loaded when the cover is closed; 
           [0023]      FIGS. 5A-5C  are top views of the utility knife showing the blade holder in different locations relative to the handle; 
           [0024]      FIG. 6  is a perspective view of the knife illustrating an alternative embodiment of a blade release; 
           [0025]      FIG. 7  is a section view illustrating a retention means for a blade releasing slide member; 
           [0026]      FIG. 8  is an exploded view sowing the slide and its relation to a disk; and 
           [0027]      FIGS. 9 and 10  illustrate the lock and un-lock positions of the release mechanism. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Referring now specifically to the Figures come up in which identical or similar parts as designated by the same reference numerals throughout, and further referring to  FIG. 1 , the self loading utility knife in accordance with the present invention is generally designated by reference numeral  10 . 
         [0029]    The utility knife  10  includes a handle  12  formed of a pair of complementary shells, a right shell  14  and a left shell  16 , together forming a substantially enclosed clamped shell arrangement having a front aperture  12   a  ( FIG. 4 ). The right shell  14  includes a lock slot  14 ( a ) and the sign is shown. While the upper edge of the right shell  14  is generally smooth and slightly curved as shown there is provided a disc cut-out  14   b  at the front end of the handle  12 , for reasons to be discussed. 
         [0030]    The left shell  16  is provided with an elongate recess  16   a  ( FIGS. 2A ,  2 B) that generally extends from the rear end of the handle to the right end as shown and generally following the curvature of the upper edge portion of the handle. A complementary or similar elongate recess is also provided on the right shell  14  (not shown) so that both of the associated elongated recesses generally follow each other and are parallel along the internal facing surfaces of the respective right and left shells. Each of the elongate recesses  16   a  include a front notch  16   b  ( FIG. 2B ) and a rear  16   c  ( FIG. 2B ). The left shell  16  is also provided with a recess  16   d  sufficiently in deep to receive a locking mechanism to be described. 
         [0031]    The left shell  16  is provided with a generally flat upper edge  18  while the right shell  14  is provided with a cut-out  20  defining a rear edge  22  and a front edge  24 , the cut-out  20  forming and defining a slot  26  extending between the rear and front edges  22 ,  24 . The lower edge  28  of the handle is shown provided with a curvature to provide an ergonomic or comfortable feel when the handle  12  is held. Ribs  30  may be provided along the lower edge  28  to provide a better grip on the handle and to prevent slippage. 
         [0032]    Within the handle  12  there is provided a carriage or blade holder  32  that includes holes  32   a  that are spaced from each other as shown in  FIGS. 3A ,  3 B. A B shaped cut-out  32   b  is provided in the upper region of the carriage between the holes  32   a , having a lower narrow portion  32   c  and a upper wider portion  32   d.    
         [0033]    The carriage  32  is provided with a front recessed region  34  that is recessed to a depth that substantially corresponds to the quick release disc to be described. A rear recessed region  36  is provided in the carriage ( FIG. 2B ) that includes an upperwardly extending notch  36   a . Mounted on the carriage  32  is a blade release mechanism  38  that includes a generally circular disc  40 . Referring, for example, to  FIGS. 2A ,  2 B, the disc  40  is actually shown as a partial disc, approximately a semi-circle with an indentation or cu-out  42   a  that defines a bearing edge  42   b . A tab  42   c  extends normal to the plane of the disc, extending through aperture  42   d  to project these partially beyond the opposing face or surface of the carriage. A rivet  42  supports the disc in rotatable relationship to the carriage so that disc  40  can rotate between locking and releasing positions, as being described. The disc  40  is also preferably provided with teeth or other serrations  44  on the upper or exposed circular portion of the disc to facilitate gripping with the thumb or the finger of the user. 
         [0034]    Referring to  FIGS. 2A and 2B , a leaf spring  46  has two opposing free ends, one of which is secured to the carriage by any suitable attachment means  48  while the other end extends into the region of the cut-out  42 A and approximate to the bearing surface  42 B of the cut-out. Leaf spring  46  has a thickness equal to or less than the depth of the front recessed region  34  so as to not to protrude beyond the face of the carriage or in any way interfere with the movements of the carriage within the handle. The leaf spring  46  is so configured and biased so that it normally abuts against the bearing edge  42   b  and causes the disc  40  to rotate to the extreme counterclockwise position, as unit  FIG. 2B , the motion being limited when the tab  42   c  engages one of the aperture  42   d  within the carriage. This extreme counterclockwise position of the disc  40  corresponds to the locking position of the blade release mechanism  38  when the tab  42   c  is in its lowermost position towards the Blade. Referring to  FIG. 3A , this is a view of the reverse side of the carriage, indicating the position of the tab  42   c , its lowermost position, corresponding to a extreme clockwise direction of the disc as unit  FIG. 3A . In this condition, the locking tab  42   c  is received within a notch b of the Blade to prevent the blade from moving within its own plane relative to the carriage. When the disc  40  is rotated in a clockwise direction (as viewed in  FIGS. 2A ,  2 B) or in a counterclockwise direction (as viewed in  FIGS. 3A ,  3 B), the tab  42   c  is lifted out of the notch b, as shown in  FIG. 3B , thereby releasing the Blade through the front aperture  12   a . The position of the disc  40  in  FIG. 40   b , therefore corresponds to the blade releasing position. The disc  40  is positioned to be accessible to the user by placement of the thumb of the user&#39;s hand that also holds the utility knife handle  12 . 
         [0035]    The specific means  48  for attaching the spring is not critical for purposes of the invention and any suitable means may be used, including press fitting within a narrow slot, welding, bonding, and the like. 
         [0036]    Provided on the inside surface of the right shelf  14  is a recessed hinged support  50  for a blade replacement cover, to be described. The hinge support includes a suitable fastener  50   a  and a hinge  50   b . The hinge support  50  is recessed below the inside surface of the left shell  16 , the hinge  50   b  extending through the left shell and being accessible to the reverse or exterior side of the left shell  16  as best shown in  FIG. 4 . 
         [0037]    Extending through the lock slot  14   a , and the rear of the right shell  14  is a carriage lock toggle  52  accessible from the exterior from the handle formed with a locking tab  52 ′ projecting into the carriage and dimensioned to be selectively received within the notch  36   a  of the rear recessed  36  of the carriage. Lock  52 ′ as dimensioned to be received within the notch  36   a  when the toggle  52  is manually lifted or moved upwardly to the position shown  2 A. Being received the notch  36   a , the locking tab  52 ′ enters the notch  36   a  and prevents the carriage from moving forwardly, as suggested in  FIG. 2A . Only when the lock toggle  52  is moved downwardly, as shown in  FIG. 2B , does the locking tab  52 ′ move out of the notch  36   a , this allowing the carriage to move towards the front of the handle as shown in  FIG. 2B . Suitable spring loading or other frictional or other means may be used to maintain the carriage lock toggle  52  in place once moved to the locking or unlocking positions so that it remains in the selected position and can only be moved to the alternate or other position when sufficient manual force is applied to the toggle  52  to move it as desired. 
         [0038]    A release button  54  generally has a T-shaped configuration, as viewed from the side and having a generally uniform thickness as viewed from the top. The release  54  includes a wide upper portion  54   a  and a narrow lower portion  54   b . Formed within the wider portion  54   a  is a transverse slot  54   c  that extends through the entire thickness of the release button. A transverse bar  56  is dimensioned to be received within the transverse slot  54   c  with some clearance so that it can be readily asserted through the transverse slot. While the transverse bar is shown to be generally rectangular, this is the presently preferred embodiment although other shapes can be used including, for example, square. The length of the transverse bar  56  is selected to have both three ends of the bar receivable within opposing elongate recesses  16   a , both the right and left shells  14 ,  16 . The transverse  56  is also configured and dimensioned to correspond to the front and rear notches  16   b ,  16   c  so that the transverse bar can also be received within those notches. 
         [0039]    Alignment pins  58   a ,  58   b  are dimensioned to be receivable within the holes  32   a  in the carriage. Again, the specific cross-sectioned configurations of the pins  58   a ,  58   b  is not critical as long as they can be received within the elongate recesses  16   a  on both of the right and left shells  14 ,  16 . The lengths of the alignment pins  58   a ,  58   b  are, therefore, substantially the same lengths as the transverse bar  58 . The alignment pins  58   a ,  58   b  are preferably configured to prevent entry into a locking engagement with the notches  16   b ,  16   c , the alignment pins having the sole functional purpose to maintain the carriage in the desired orientation and prevent it from excessively rotating in relation to the handle. The alignment pins  58   a ,  58   b  do not however, have any locking function but only to maintain the carriage and a desired aligned orientation. 
         [0040]    The release button  54  is provided, on the narrow portion  54   b  with a downwardly open bore  54   b  dimension for receiving a helical compression spring  60  to normally urge the release button  54  to move upwardly in relation to the carriage. The release button  54   b  is, accordingly, moveably mounted relative to the carriage for limited upward and downward movements within the correspondingly shaped upper opening in the carriage. To maintain the release button  54  within the plane of the carriage any suitable may used. In the presently preferred embodiment, generally transverse movements of the release button  54  in relation to the carriage is prevented by providing recesses  32   e  on forward and opposing edges  32   e  along the narrow portion  54   b  of the release button, while correspondingly dimensioned ribs  32   f  are provided on the carriage so that the ribs  32   f  can be slidingly received within the recesses  32   e  with some clearance so that the release button  54  can freely move upwardly and downwardly but not transversely in relation to the carriage. 
         [0041]    Referring to  FIG. 4 , the cover lock  62  includes a slide number  64  having an outwardly extending Fig. grip  64   a  accessible to a user from outside of the handle and an inwardly extending latch extending latch  64   b . Any suitable spring or other biasing means may be used to normally urge the finger grip  64   a  and latch  64   b  towards the front of the housing or aperture  12   a . By manually gripping the finger grip  64   a  and applying a rearward force to it the entire latch  64   b  can be retracted below the cover plate  64   d  ( FIG. 4 ). 
         [0042]    A cover  66  serves a couple of different functions. The cover  66  includes a generally flat plate  66   a  that is hingedly connected to the hinge  50   b . on the exterior side of the plate  66   a  is a spring clip  66   b  inwardly formed therewith an configured to slide over a retaining member such as a belt. Extending inwardly to the opposite side of the location of the clip  66   b , is a locking tab  66   c  positioned and configured to clear the cover plate  64   d  and enter into the recess  16   d  with the slide  64  is fully retracted against the action of a spring or other biased member. Once the tab  66   c  is below the cover plate  64   d  and the slide  64  is released the latch  64   b  moves into a position above the tab  666   b  to lock it and prevent the clip cover  66  from opening. However, when the finger grip  64   a  is moved rearwardly, as viewed in  FIG. 4 , the latch  64   b  moves below the cover plate  64   d , thereby releasing the tab  66   c . A leaf spring  66   d  is noted in any suitable manner on the plate  66   a  as shown in  FIG. 4 , being arranged to apply a force on a stack of Blades that are received within the blade compartment  70  formed within the left shell  16  to be appreciated that the leaf spring  66   d  urges one or more Blades to be urged inwardly in the direction of the carriage  32  disposed on the other side of the blade compartment  70 . 
         [0043]    The operation of the utility knife  10  will now described. Initially, the finger grip  64   a  is manually urged towards the rear of the handle  12  to release the tab  66  as described. The clip cover  66  can now be pivoted about the hinge  50   b  to the fully opened position as shown in  FIG. 4 . The stack of Blades can now be inserted into the blade compartment  70 . In the presently preferred embodiment conventional trapezoidal Blades with two spaced notches b as shown are used. However, it will be evident to those skilled in the art that differently shaped blades can be used and the blade compartment  70  and the carriage suitably modified to accommodate differently shaped blades with different degrees of advantage. Once the blades are inserted within the compartment  70 , the finger grip  64   a  is moved towards the rear of the handle  12  to move the latch  64   b  into a fully retracted condition below the cover plate  64   d . The cover plate  66   a  can now be pivoted about the hinge b to a fully closed position and the finger grip  64   a  released to engage the tab  66   c  and lock the cover plate. 
         [0044]    When the carriage or blade holder  32  is moved to its fully retracted position to the rear of the handle  12  the recess  16   d  is slated for the blade is moved into alignment with the blade compartment  70  so that the recess  16   d  can receive the rear portion of the Blade as suggested in  FIG. 3A . Because the recess  16   d  has a depth substantially corresponding to the thickness of the Blade at least a portion of the blade that meets with the contour of the recess  16   d  receives the corresponding portion of the blade as shown in  FIG. 3A . The surface of the Blade facing outwardly on the page in  FIG. 3A  is substantially co-extensive with the raised surface of the carriage in which the recess  16   d  is formed, to effectively provide a smooth and continuous surface between the carriage and the blade in a generally common plane. The movement of the Blade into the recess  16   d  is facilitated by the pressure applied by the leaf spring  66   d  that forces the blade to the compartment  70  towards the carriage and the recess  16   d.    
         [0045]    Once a Blade is received within the recess  16   d  of the left shell, the tab  42   c  is also received within one of the notches b in the blade as shown in  FIG. 3A . Since the blade is captured between the carriage and the inner surface of the left shell  16  the blade is immobilized laterally and also longitudinally by the tab  42   c . To move the carriage from the retracted position shown in  FIG. 2A  to the extended position shown in  FIG. 2B  the release button  54  is depressed downwardly against the action of the spring  60 . When so depressed, the transverse bar  56  mounted on the release button is moved out of the rear notch  16   c  to unlock the button from the rear position. Application of a forward pressure on the release knob while the button is depressed downwardly allows the transverse bar  56  to slide within the elongated recesses  16   a  until the transverse bar  56  reaches the front notch  16   b . A release button  54  causes the spring  60  to urge the transverse bar  56  into the notch  16   b  and thereby lock the carriage against longitudinal frontward or rearward movements. In the forward position shown in  FIG. 2B  the blade is locked and ready to be used. Similarly, to retract the Blade the release button  54  is depressed while simultaneously applying a force on the release button in a rearward direction. This releases the transverse bar  56  from the notch  16   b  and allows both the transverse bar  56  as well as the alignment pins  58  to slide through the elongated recesses  16   a  in the two right and left shells,  14 ,  16 . This is also illustrated in  FIGS. 5A-5C . In  FIG. 5A , the carriage is in a forward position but no blade is exposed because a blade has not yet been lodged onto the carriage. Rearward movement of the release button  54  brings the carriage to the rearmost position in the spring  66   d  urges a blade to be received onto the surface of the carriage and more specifically within the blade recess  16   d . After a blade is inserted, as suggested by the arrows in  FIG. 5B , a further sliding movement of the release button  54  brings the carriage forward and together with it a Blade that has now been secured to the carriage. 
         [0046]    To release a defective or used blade, the carriage is moved to the forward most or extended position as shown in  FIGS. 1 and 2B . As a result of the disc cut-out  14   b , the release disc  40  is only accessible and even visible in that extended position. When the carriage is retracted the disc  40  is dimensioned so as not to protrude above the upper edge of the handle. Therefore, when the carriage and blade are retracted the quick release disc  40  is not accessible and cannot be gauged to inadvertently release the blade. However, in the position shown in  FIGS. 1 and 2B ,  1 B,  2 B and  3 A, a user&#39;s thumb of the hand holding the utility knife can contact the disc and pull towards the back causing the disc to rotate in a clockwise direction in Fig. B or in a counterclockwise direction in  FIG. 3A . This lifts the tab  42   c  out of a notch of the blade and the blade can be pulled forwardly through the front aperture  12   a . Now, after the blade is removed, movement of the carriage towards the rear of the handle, as suggested in  FIG. 5B , will result in the utility knife automatically reloading and on the blade from the blade compartment  70  as described. 
         [0047]    Once the utility knife has been used and is no longer needed the carriage can be retracted to the rear of the handle  12  and the carriage lock toggle can be lifted or raised to the position suggested in  FIG. 2A  to lock the carriage. 
         [0048]    In another embodiment illustrated in  FIGS. 6-10 , a disk  80  is not accessible by a user but is itself manipulated by a slide member  70  movable in a slot  72  formed in shell  14 . In one instance, the slide  70  includes a head  74  for manipulation by a user&#39;s finger and a shaft portion  75  ( FIG. 8 ) extending towards the disk  80 . The shaft extends through a smaller slot  72   a  formed in the handle and includes a reduced-diameter neck portion  76  that, in combination with a clip  77  retains the slide in slot  72   a , thereby permitting lateral movement of the slide while keeping it in a fixed position relative to the disk  80 . Additionally, the head  74  includes two flat portions  78  ( FIG. 8 , only one visible) for mating with two corresponding flat portions  79  ( FIG. 6 , only one visible) formed on slot  72 . The flat portions  78 ,  79  work together to prevent rotation of the slide  70  in operation. 
         [0049]    As shown in  FIG. 7 , the slide  70  is acted upon by a leaf spring  85  that biases the slide towards the front of the knife handle  12 . Notably, in the embodiment shown, leaf spring  85  operates in conjunction with leaf spring  46  that biases the disk  80  in a position whereby the blade is locked in the blade holder. As shown in  FIG. 8 , a first side of the disk  80  includes a cut-out portion  90  that interacts with a distal end of the shaft  75  as the slide  70  is moved by a user from a forward position relative to the handle  12  to a rearward position. In operation, the cut-out  90  causes the disk  80  to rotate as the slide  70  is moved in a rearward direction.  FIG. 9  illustrates a locked position wherein a tab  95  on a second side of the disk  80  interferes with a notch b formed in the blade B.  FIG. 10  illustrates an unlocked position wherein the tab no longer interferes with the cut out as a result of the slide  70  being moved in a rearward direction in slot  72   a  and the disk  80  rotating in a clock wise direction. 
         [0050]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.