Abstract:
A utility knife comprising a casing, blade moving mechanism slidably mounted within the casing, the blade storage in the casing, the blade storage comprising a guide finger under which blades are stacked and along which blades are slidably movable. The blade moving mechanism is adapted to be moved to a position opposite the guide finger and a mechanism for advancing blades toward the blade moving mechanism along the guide finger. The blade moving mechanism having a blade pickup finger and the blade moving mechanism adapted to move a blade off of the guide finger and on to the blade pick up mechanism.

Description:
BACKGROUND 
     The present invention relates to utility knives and more particularly to utility knives in which a new blade can be automatically replaced in the knife. 
     Utility knives have been in use for many years. They usually comprise a blade movable within a casing. The blade is pushed forward in order to expose the cutting edge of the blade and when desired the blade may be withdrawn within the casing so that it does not pose a hazard. Some utility knives provide for the blade to be removed and automatically replaced after the cutting edge becomes dull or for some other reason. Many of these utility knives comprise complicated mechanisms for exposing and retracting the blade and for removing and replacing the blade as well as for locking the blade in extended or retracted positions. Many of such utility knives are expensive to manufacture, are complex to use and are difficult to assemble. 
     OBJECTS 
     The present invention overcomes these defects and has for one of its objects the provision of an improved utility knife which is simple to use. 
     Another object of the present invention is the provision of an improved utility knife in which the blades can be easily placed in an extended or a retracted position. 
     Another object of the present invention is the provision of an improved utility knife in which blades can be easily removed and replaced automatically. 
     Another object of the present invention is the provision of an improved utility knife in which the blade can be easily locked in an extended or retracted position. 
     Another object of the present invention is the provision of an improved utility knife which is simple to use. 
     Another object of the present invention is the provision of an improved utility knife which is inexpensive to manufacture. 
     Another object of the present invention is the provision of an improved utility knife which may be easily assembled. 
     Other and further objects will be obvious upon the understanding of the illustrative embodiment about to be described, or which 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. 
    
    
     DRAWINGS 
     A preferred embodiment of the invention has been chosen for the purposes of illustration and description and is shown in the accompanying drawings forming a part of the specification wherein: 
     FIG. 1 is an exploded perspective view of a utility knife made in accordance with the present invention. 
     FIG. 2 is a perspective view of the second casing half of the utility knife of the present invention. 
     FIG. 3 is a sectional view taken along line  3 — 3  of FIG.  2 . 
     FIG. 4 is an elevational view of a first casing half of the utility knife. 
     FIG. 5 is a top view of the interior of the utility knife showing the position of some of the parts when the blade is in extended position. 
     FIG. 6 is a top view similar to FIG. 4 showing the position of some of the parts when a new blade is to be added. 
     FIG. 7 is a sectional view taken along line  7 — 7  of FIG.  5 . 
     FIG. 8 is a sectional view taken along line  8 — 8  of FIG.  5 . 
     FIG. 9 is a top plan view of a blade moving slide used with the present invention. 
     FIG. 10 is a bottom plan view thereof. 
     FIG. 11 is a rear plan view thereof 
     FIG. 12 is a plan view of one side thereof. 
     FIG. 13 is a plan view of the other side thereof. 
     FIG. 14 is a top plan view a control slide used with the present invention. 
     FIG. 15 is a side plan view thereof. 
     FIG. 16 is a front plan view thereof. 
     FIG. 17 is a side plan view partly broken away showing the utility knife in the process of receiving a new blade. 
     FIG. 18 is a side plan view similar to FIG. 17 showing the blade in its extended position. 
     FIG. 19 is a side plan view similar to FIG. 18 showing the blade in its retracted position. 
     FIG. 20 is a sectional view taken along line  20 — 20  of FIG.  17 . 
     FIG. 21 is a sectional view taken along line  21 — 21  of FIG.  18 . 
     FIG. 22 is a fragmentary side plan view showing the position of the parts when the blade is locked in its extended position. 
     FIG. 23 is a side plan view similar to FIG. 22 showing the position of the parts when the blade is locked in its retracted position. 
     FIG. 24 is a schematic side view showing the relationship of the slides before being assembled together. 
     FIG. 25 is a schematic plan view showing the relationship of the slides when assembled together. 
     FIG. 26 is a sectional view taken along line  26 — 26  of FIG.  25 . 
     FIG. 27 is a schematic plan view showing the relationship of the slides when the blade is locked in position. 
     FIG. 28 is a sectional view taken along line  28 — 28  of FIG.  27 . 
     FIG. 29 is a sectional view taken along line  29 — 29  of FIG.  27 . 
    
    
     DESCRIPTION 
     The blade B preferably used with the present invention is best shown in FIG.  4  and is trapezoidal in shape having a lower cutting edge C, inwardly inclined end edges E and a shorter top edge T having a pair of notches N. It will be understood that other blades may also be used with the present invention. 
     Referring to the drawings and more particularly to FIGS. 1,  2  and  3  the utility knife  1  of the present invention comprises a first casing half  2  and a second casing half  3  which are assembled together to form the complete casing  4 . The first casing half  2  has a side wall  6 , a top wall  5 , a bottom wall  7 , a rear wall  8 , and a front wall  9 . The front wall  9  is angled with a partial mouth slot  10 . The top wall  6  has an elongated partial slide slot  11  therein. The rear wall  8  has a slot  12  in its upper end and an opening  13  at its lower end. The side wall  6  is also provided with an angled twine cutting slot  14  near its if front wall  9 . A plurality of magnets  15  and  16  may also be provided in side wall  6  to hold the blades B in place. The side wall  6  has a blade leveling assembly  20  on which a pivoted blade leveling arm  21  is mounted. The blade leveling arm  21  is spring pressed by spring  22  to a position at right angles to the blade leveling assembly  20  (FIG. 5) but is pivotable to a position in lengthwise alignment with and over the blade leveling assembly  20  (FIG.  6 ). The side wall  6  below the top wall  5  is provided with a plurality of lock notches  17  and an undercut of elongated slide groove  18  on each side thereof. 
     The second casing half  3  comprises a top wall  25 , bottom wall  26 , front wall  27 , rear wall  28  and side wall  29 . The front wall  27  is angled and has a partial mouth slot  30  adapted to match the partial mouth slot  10  in the first casing half  2  in order to form a mouth  10 - 30 . The side wall  29  also has a twine cutting slot  14  to match the twine cutting slot  14  in the first casing half  2 . The side wall  29  has a trapezoidally shaped opening  31  to receive a plurality of blades B and which is adapted to be closed by a trapezoidally shaped cover  33 . The side wall  29  also has a blade supporting platform  34  mounted on a plurality of spaced platform supports  35  and an inwardly extending blade notch guide finger  36  under which blades B are stacked with the blade notch guide finger  36  inserted in the notch N of the blades and along which blades B will slide inwardly away from the side wall  29  (FIGS.  2  and  3 ). The upper part of the interior of the side wall  29  has a plurality of lock notches  37  adopted to cooperate with corresponding lock notches  17  on the first casing half  2  and an undercut elongated slide groove  39  on each side thereof adapted to cooperate with matching slide groove  18  in the first casing half  2  to form slide groove  18 - 39 . The top wall  25  has an elongated partial slide slot  38  to match the partial slide slot  11  in the first casing half  2  to form a slot  11 - 38 . The top wall  25  has a lock hook  49  adapted to enter into the slot  12  of the top wall  5  in the first casing half  2  to hold the casings  2  and  3  together. Screw holes  40  may also be provided at various points on both casing halves  1  and  2  to hold them together. A blade ejection button  41  is provided at the front end of the side wall  29  to permit a blade B to be removed, as will be further described hereinbelow. 
     Blades B are stored in stacked relationships in the second casing half  3  through opening  31  and are supported by the support platform  34 . They are also held in place by the magnet  16  against which they abut. When a blade B nearest the magnet  16  is removed, the other blades will be attracted toward the magnet  16  and move inwardly. The cover  33  of the opening  32  also has a spring  42  which will push the blades B inwardly against the magnet  16 . The blades B are also held in place in stored and stacked positions beneath pivoted blade-leveling arm  21  which is in its extended position so that the blades B are held in place between the blade-leveling arm  21 , the support platform  34 , the magnet  16  and the spring  42 . The blades B are held against lateral movement by the inwardly directed guide finger  36  which is inserted in one of the notches N at the top edge T of the blades B and along which the blades B slide when moving inwardly. The guide finger  36  terminates at the inner edge of the second casing half  3 . 
     A blade moving slide  50  (FIGS. 9-13) comprises a top finger button  51  and a downwardly extending body  52  adopted to extend through and slide along slide slot  11 - 38  in the top wall  5 - 25  of the casing  4 . A pair of spaced resilient lock fingers  53  extend rearwardly from the body  52 . Each lock finger  53  has a stop head  54  extending away from each other, a stop tooth  55  extending toward each other and a grip edge  32  extending toward each other between the stop teeth  55  and the body  52 . The lock heads  54  will normally slide in the slide grooves  18 - 39  in the two casing halves  2 - 3 . A stop block  62  extends from each side of the body  52  above the lock fingers  53  for a short distance. Extending downwardly from the body  52  is an elongated platform  56  at right angles to body  52  with a downwardly extending support bar  57  at right angles to the platform  56 . A resilient blade carrier  58  is attached to the support bar  57  by screw  61  and has a lower pick-up finger  59  extending inwardly through lower opening  63  in the support bar  57  and an upper blade release finger  60  also extending inwardly through upper opening  64  in the support bar  57 . The blade carrier  58  is resilient so that its fingers  59  and  60  may move inwardly in and out of the openings  63  and  64  in the support bar  57 . 
     A control slide  70  (FIGS. 14-16) has a top finger button  71  and a downwardly extending body  72  which slides in slide slot  11 - 38  in the top wall of the casing. The body  72  has a pair of gripping arms  73  extending forwardly therefrom. Each gripping arm  73  has a stop  74  extending inwardly toward each other. The space between the gripping arms  73  is equal to or is greater than the distance between the stop block  62  on the body  52  of blade moving slide  50 . The distance between grip edges  32  on the lock arms  53  is less than the thickness of the body  52  of blade moving slide  50 . The distance between the grip edges  32  and the body  72  on central slide  70  is approximately equal to the length of the body  52  of the blade moving slide  50 . 
     The two slides  50  and  70  are adapted to face each other and slide in the slide slot  11 - 38  with their lock fingers  53  and gripping arms  73 , respectively, pointing toward each other and slidable adjacent slide grooves  18 - 39 . As shown in FIG. 24,  25  and  27 , when the slides  50  and  70  face each other the lock fingers  53  of the blade moving slide  50  are located below the gripping arms  73  of the control slide  70 . The lock fingers  53  closely embrace the body  72  of control slide  70  so that the two slides  50  and  70  can move together, i.e. the body  72  of the control slide  70  is held between body  52 , arms  53  and grip edges  32  of blade moving slide  50 . The control slide  70  can be separated slightly from the blade moving slide  50  since the flexibility of the grip fingers  53  will permit the body  72  thereof to move between grip edges  32 . This will spread grip finger  53  apart with the body  72  being held there by stop heads  54 , as will be more fully disclosed hereinafter. 
     In order to pick up a new blade B the two slides  50  and  70  are moved together rearwardly toward the stack of blades. The body  52  of the blade moving slide  50  lies in front of the body  72  of the control slide  70  between lock fingers  53  but does not exert any outward force on the lock fingers  53 . When the slides  50  and  70  are moved adjacent to the stack of stored blades B, the slide  70  moves the pivoted blade leveling arm  21  out of the way to its folded position to free the stored blades B from any top pressure. The body  72  of the control slide  70  bears against the blade leveling arm  21  and keeps it in its folded position. In this position the spring  42  in the cover  33  will move the blades B inwardly along the guide finger  36  toward magnet  16  so that the innermost blade is moved off the end of the guide finger  36  and onto the pick-up finger  59  of the resilient blade carrier  58  which is in its extended position through lower opening  63  which is inserted in the notch N and holds the blade B in place. When the slides  50  and  70  are moved forward, the pickup finger  59  will move the blade B forward to a position adjacent magnet  15 . The body  72  of control slide  70  releases the blade leveling arm  21  which returns to its normal extended position by means of spring  22 . The blade B is held steady because its upper edge is held by the pickup finger  59  in one of the notches N and by the magnet  15 . In this position the slides  50 - 70  can be moved to the forward end of the casing  4  in order to expose the blade B . After use, the blade can be retracted back into the casing  4  by moving the slides  50 - 70  back. 
     In order to lock the blade B in a particular position (either with the blade exposed or with the blade retracted) both slides  50  and  70  are moved to the desired position. In order to lock the blade B in that position, the control slide  70  is moved back slightly away from the blade moving slide  50  so that its body  72  now moves between the grip edges  32  of two locking arms  53  of the slide  50  to spread them apart. Further rearward movement of the body  72  away from slide  50  is prevented by the stop teeth  55 . The stop heads  54  are thereby moved into the lock notches  17 - 37  in the side walls  6 - 29  to lock the blade B in a position When it is desired to again move the blade to a different position, the control slide  70  is moved forward toward the control slide  50  so that its body  72  is not exerting any outward force on the grip edges  32  to thereby permit the lock fingers  53  to return to their normal positions and cause the stop heads  54  to move out of the lock notches  17 - 37 . Hence, the two slides  50  and  70  are again free for movement together with blade B along the slide slot  11 - 38  and the slide groove  18 - 39 . 
     A spring pressed blade ejection button  41  is mounted at the forward end of the second casing half  3  and biased outwardly by spring  44 . The ejection button  41  is at the same level as the upper blade release finger  60  extending from the resilient blade carrier  58 . When it is desired to remove the blade B, the blade B is placed in its most forward position so that it protrudes from the mouth  9 - 27 . At this point the inner edge  43  of the ejection button  41  is on the same level with the upper blade release finger  60  in the blade carrier  58 . When the ejection button  41  is pressed inwardly against the bias of spring  44 , its inner edge  43  strikes the release finger  60  and moves it inwardly. This flexes the resilient support bar  57  inwardly to move the pick up button  59  inwardly and out of the upper notch N in the blade B. This releases the blade B and the blade B can then be removed manually from the mouth  9 - 30 . 
     It will thus be seen that the present invention provides an improved utility knife in which the blades can be easily placed in an extended or retracted position, in which blades can be easily removed and replaced automatically, in which the blade can be easily locked in an extended or retracted position and which is simple to use and inexpensive to manufacture. 
     As many varied modifications of the subject matter of this invention will become apparent to those skilled in art from the detailed description given herein above, it will be understood that the present invention is limited only as provided in the claims appended hereto.