Patent Publication Number: US-2012030949-A1

Title: Folding utility knife

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application is a continuation of U.S. patent application Ser. No. 12/803,466, filed Aug. 6, 2010, and entitled “FOLDING UTILITY KNIFE,” which is a continuation of U.S. patent application Ser. No. 11/986,725, filed Nov. 26, 2007, and entitled “FOLDING UTILITY KNIFE,” each of which is incorporated herein in its entirety by reference. 
     The subject matter of U.S. patent application Ser. No. 11/800,684, filed May 7, 2007, and entitled “FOLDING UTILITY KNIFE,” is incorporated into the present application in its entirety by reference. 
    
    
     BACKGROUND 
     The present invention relates to a utility knife and more particularly to a folding utility knife in which the blade may be folded into the handle when the knife is not in use. 
     Folding utility knives have been in use for a number of years. In such knives the blades are mounted on a blade holder which is foldable within a handle when the knife is not in use. However, some of these folding utility knives have many movable parts which makes them difficult to use and expensive to manufacture. In addition, in some of these folding utility knives replacement of the blade is a complicated operation which may require the use of special tools. 
     Objects 
     The present invention overcomes these problems and has for one of its objects the provision of an improved folding utility knife in which the blade holder may be easily folded into the handle. 
     Another object of the present invention is the provision of an improved folding utility knife in which the blade is held securely on the blade holder. 
     Another object of the present invention is the provision of an improved folding utility knife in which improved means are provided for replacing the blade on the blade holder. 
     Another object of the present invention is the provision of an improved folding utility knife which is simple to use and inexpensive to manufacture and maintain. 
     Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to described, or will be indicated in the appended claims and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings forming a part of the specification, wherein: 
         FIG. 1  is a side plan view of a utility knife made in accordance with the present invention. 
         FIG. 2  is a top plan view thereof. 
         FIG. 3A  is a partial sectional side view showing the position of the parts when the folding utility knife is in its unfolded position. 
         FIG. 3B  is a partial sectional side view similar to  FIG. 3A  showing the position of the parts when the folding utility knife in a partially folded position. 
         FIG. 3C  is a partial sectional side view similar to  FIG. 3A  showing the position of the part when the folding utility knife in its fully folded position. 
         FIG. 4  is a side plan view of the blade holder of the present invention. 
         FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 4  showing the blade locking means in its blade locking position. 
         FIG. 6  is a sectional view taken along line  6 - 6  of  FIG. 3 . 
         FIG. 7  is a sectional view similar to  FIG. 4  showing the blade locking means in its blade releasing position. 
         FIG. 8  is a sectional view taken along the line  8 - 8  of  FIG. 7 . 
         FIG. 9  is an exploded view of the blade holder of the present invention. 
         FIG. 10  is a perspective view showing the position of the parts with the blade releasing mechanism in its blade locking position. 
         FIG. 11  is a perspective view similar to  FIG. 10  showing the position of the parts with the releasing mechanism in its blade releasing function. 
         FIG. 12  is a perspective view similar to  FIG. 10  showing the blade being replaced. 
         FIG. 13  is an enlarged sectional detail showing the position of the part when the blade is in its locked position. 
         FIG. 14  is an enlarged sectional detail showing the position of the parts when the blade is in its unlocked position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, the folding utility knife  1  of the present invention comprises a handle  2  and a blade holder  3 . 
     The handle  2  comprises a pair of handle halves  2 A and  2 B each having an outer side wall  11 , an upper edge  7  and a lower edge  9 . A rear spacer  4  is provided between the handle halves  2 A and  2 B to maintain the handle halves  2 A and  2 B separated and to create a space  5  between handle halves  2 A and  2 B. The spacer  4  and the handle halves  2 A and  2 B may be held together by fasteners  6  which pass through the spacer  4  and the handle halves  2 A and  2 B in order to hold them together. The upper edge  7  of the handle halves  2 A and  2 B (i.e. the entire handle  2 ) has a finger notch  8  and the lower edge  9  of the handle halves  2 A and  2 B (i.e. the entire handle  2 ) may be undulated in order to permit the user&#39;s fingers to grip the handle  2 . If desired, a clip  10  may be mounted on a side wall  11  of the handle halves  2 A and/or  2 B to permit the utility knife  1  to be fastened onto the user&#39;s belt or some other convenient place. 
     Interposed between the handle halves at  2 .A and  2 B and along the upper edges  7  of the handle halves  2 A and  2 B there is provided a lock lever assembly  15  ( FIGS. 3A to 3C ) which is pivotally mounted between the handle halves  2 A and  2 B on a pivot pin  16  which extends through the two handle halves  2 A and  2 B and the lock lever assembly  15 . The lock lever assembly  15  is preferably a two arm lever having front and rear arms  17  and  18 , respectively. The front arm  17  is provided with a downwardly extending lock finger  19 . Below the rear arm  18  of the lock lever assembly  15  there is provided a spring  14  which normally bears against the bottom edge of the rear arm  18  to force the rear arm  18  upwardly and the front arm  17  downwardly around the pivot  16  so that rear arm  18  protrudes above the notch  8 . It will be seen that when the rear aim  18  of the lock lever assembly  15  is pressed down manually through the notch  8  against the action of spring  14 , the front arm  17  will be raised. 
     The blade holder  3  of the present invention comprises a rear end  31  and a front end  32 . The rear end  31  of the blade holder  3  has rear edge  31 A, bottom edge  31 B and upper edge  31 C. The blade holder  3  is pivotally mounted in the space  5  between handle halves  2 A and  2 B on a pivot pin  30 . The upper edge  31 C of the rear end  31  has a lock groove  33  into which the downwardly extending lock finger  19  of the lock assembly  15  is adapted to enter when the blade holder  3  is in its extended or unfolded position. 
     The blade holder  3  comprises a thin wall  34  and a thin guard wall  35  which are held together by any well known means such as by welding them together or by fastening them together with suitable fasteners  36 . If desired they may be made of one piece and integral with each other. The main wall  34  is thinner than the upper edge  31 C to form an upper hollow control area  50  and a lower slit  52  therebelow which is adapted to receive and hold a blade B between walls  34  and  35 . The blade B preferably hag a lower cutting edge  37  and spaced notches  38  in its upper edge  39 . The blade B is adapted to slide in and out of a slit  52  formed between the walls  34  and  35 . 
     A blade lock lever arm  45  is pivotally mounted within the groove  50  on a pivot pin  46  pivotally mounted on upper edge  31 C for movement in a plane perpendicular to the plane of the side walls  34  and  35 . A pair of opposed panels  51  are mounted to enclose the upper area  50  on opposed sides of the upper edge  31 A. The blade lock lever  45  has a front arm  47  and a rear arm  48  with a downwardly extending blade finger  49  depending from its front arm  47  ( FIGS. 13 and 14 ). The blade finger  49  has re-entrant tip  43  adopted to enter a groove  38  on the blade B. 
     When the blade lock lever  45 , is pivoted around pivot  46  in one direction the tip  43  of its blade finger  49  will enter into one of the upper notches  38  on blade B in order to lock the blade B in place. When it is desired to remove and replace the blade B the blade lock arm  45  is pivoted in the opposite direction to move the tip  43  of the blade finger  49  out of the blade notch  38  to release the blade B and permit it to be slid out of the slit  52 . The rear arm  48  of the blade lock lever  45  has a plate  60  depending therefrom. A spring  61  is mounted on one side of the plate  60  the opposite side has a finger button  42  which extends through one of the plates  31 . Normally the spring  61  biases the lever on  45  so that the front arm  47  is located toward blade B with the tip  43  of the lock finger  49  entered into the notch  38  in the blade B. When the finger button  42  is pushed inwardly against the bias of the spring  61 , the rear arm  48  of the lock lever  45  is in a pushed-in position thereby moving the front arm  47  away from blade B and the finger tip  43  out of the notch  38  in the blade. It will be understood that rather than a single blade finger  49 , as shown, it is within the purview of the present invention to have a plurality of blade fingers  47  to enter the notches  38  in the blade. 
     In operation, the utility knife  1  is placed in its operative unfolded position with the blade holder  3  unfolded and ready to be used. The blade B is held in the slit  52  by the top  43  of the blade finger  47  of the blade lock arm  45  (which is in its normal position) extending into a notch  38  in the top edge  39  of the blade B. The lock finger  19  of the front arm  17  of the lock lever assembly  15  is in its lower position (because of the pressure of spring  14  on rear arm  18 ) and is positioned in the groove  33  in the blade holder  3  in order to hold the blade holder  3  in its unfolded position. The rear arm  18  of the lock lever assembly  15  is in its raised position and protrudes above the finger notch  8  at the top edge  7  of the handle  2 . 
     When it is desired to place the utility knife  1  into its folded inoperative position, the rear arm  18  of the lock lever assembly  15  is pressed down manually through the notch  8  against the bias of the spring  14 . This causes the front arm  17  of the lock lever assembly  15  to be raised thereby moving the lock finger  19  out of the groove  33  to release the blade holder  3  and permit it to pivot downwardly around the pivot pin  30  ( FIG. 4 ). This may be accomplished by pushing down on the finger knob  41 . The blade holder  3  is then pivoted down completely into the space  5  between the handle halves  2 A and  2 B ( FIG. 5 ). When pressure on rear arm  18  is released, the spring  14  moves the rear arm  18  back to its original raised position by the tension of the spring  14 . This causes the lock finger  19  to bear against the button edge  31 B of the blade holder  3  thereby holding the blade holder  3  in its folded position. 
     When it is desired to use the blade B the reverse procedure is followed. The blade holder  3  is pivoted in the opposite direction. It may be desirable for the rear arm  18  of the lock lever assembly  5  to again be depressed manually to assist in unfolding the blade holder  3 . The blade holder  3  is continued to be rotated counter-clockwise (as seen in  FIG. 4 ) until the lock forger  19  of the front arm  17  enters into the groove  33  in the rear end  31  of the blade holder  3  in order to hold the blade holder  3  in its extended position. 
     When it is desired to replace a blade B the blade holder  3  is placed in its unfolded position (as shown in  FIGS. 3A to 3C ) and the blade lock arm  45  is moved in one direction around pivot  46  by means of finger tab button  42  against the bias of spring  61  thereby moving the tip  43  of the blade finger  49  out of the notch  38  in the upper blade edge  39  of the blade B to release the blade B. The blade B can then be moved out of the blade holder  3  through slit  52  and a new blade B can be placed therein through the slit  52 . When this occurs the push button  42  is released so that the blade lock arm  45  moves the top  43  of the blade finger  49  into the notch  38  in the blade B to lock the blade B in place. 
     As many and varied modifications of the subject matter of this invention will become apparent to those skilled in the art from the detailed description given hereinabove, it will be understood that the present invention is limited only as provided in the claims appended hereto.