HK1016530A - Utility knife with blade magazine - Google Patents

Description

Utility knife with blade magazine

The present invention relates to a knife, commonly referred to as a utility knife, having a hand-holdable housing carrying a thin cutting blade which projects forwardly from the housing when in its operative position. Most blades of such cutters are double-ended, i.e. have opposite ends which both serve as cutters, so that when one end becomes dull, the blade can be reversed, leaving the other end forming the working end. Such cutters are generally trapezoidal in shape with a lower cutting edge meeting the inclined end edge of the blade forming a sharp cutting point at each end.

Such utility knives find a variety of uses in situations where a hand held tool with a sharp blade is desired. When the blade is used with one or both of its ends dulled, it is necessary to replace the worn blade with a new one. For most utility knives, the old blade is manually removed from the housing and a new blade is attached, which is not only time consuming but also involves the risk of injury to the operator for the old or new blade. Attempts have been made to provide utility knives having a new blade source in the housing and having a manual mechanism for bringing the new blade into the operative position. However, for various reasons, such blades have not proven particularly satisfactory in practice.

To this end, it is an object of the present invention to provide an improved utility knife having a new blade supply within its housing that facilitates the withdrawal of a used blade into the housing and the movement of a new blade to a working position.

According to the invention there is provided a knife comprising a hand holdable housing having a front end and a rear end, and a blade magazine removably mounted in the housing and rotatable about an axis parallel to the longitudinal axis of the housing extending from said front end to said rear end. The magazine has a series of radially and longitudinally extending circumferentially spaced blade receiving slots for respectively receiving thin blades having cutting edges at least at one end, each slot having a leading end which is divergent to enable a blade therein to be removed from the magazine by forward movement of the leading end through the slot.

The housing also carries a slidable transport mechanism having an actuator projecting from the housing for engagement, the actuator being slidable between forward and rearward positions. The transport mechanism also has a blade engaging arm within the housing for positioning the actuator to a forward position such that the blade carried by the arm projects from the front end of the housing into an operative position, and movement of the actuator from the forward position to a rearward position causes the blade to be retracted from the operative position into the housing and into the cartridge interior slot. The magazine can be rotated to remove a withdrawn blade from the arm of the transport mechanism and to position a new blade from the other slot onto the arm, in a subsequent movement being brought to the working position by the actuator.

The cartridge may include a body rotatable about a longitudinal axis and having a forward end and a rearward end, the body having a series of radially and longitudinally extending circumferentially spaced blade receiving slots for respectively receiving thin blades having cutting edges at least at one end, each slot having an open forward end for allowing the blade therein to be withdrawn from forward movement through the forward end of the slot.

The rotatable body has first and second portions, the first portion having a first end with an array of radially and longitudinally extending circumferentially spaced first slot forming fingers extending longitudinally from the first end to an opposite end of the first portion, and the second portion having a second end with an array of radially and longitudinally extending circumferentially spaced second slot forming fingers extending longitudinally from the second end to an opposite end of the second portion.

The first portion is combined with the second portion by longitudinal movement of the first fingers between the second fingers to provide a blade receiving slot between each adjacent pair of the first and second fingers. Each slit is open at least at one end thereof to enable the blade in the slit to be withdrawn therefrom by longitudinal sliding movement by the delivery mechanism through the forward end of the slit.

The first finger of the blade magazine may have a forward end portion slidably fitted to and supported by an end portion of the second portion, and the second finger may have a forward end portion slidably fitted to and supported by an end portion of the first portion.

Each of the first and second fingers of the magazine has a radially outwardly facing outer surface with a circumferentially extending groove, the magazine also having a blade retaining ring circumferentially spaced around the magazine itself except for the gap and located in the grooves of the first and second fingers. The blade retaining ring is non-rotatably retained in the housing with the circumferential gap coinciding with the path of travel of the conveyor mechanism, thereby allowing an arm of the conveyor mechanism to enter the circumferential gap to remove a used blade from the arm and attach a new blade to the arm.

Each slot of the magazine may contain a blade having a recess in a radially outer edge thereof with a blade retaining ring passing through the recess of each blade.

At least one of the sections of the cartridge may have a stub shaft projecting longitudinally outwardly from one end thereof, and the housing may have a manually rotatable portion capable of receiving the stub shaft in a relatively non-rotatable manner, and rotation of the manually rotatable portion of the housing thereby causes removal of a used blade and attachment of a new blade relative to the arm of the transport mechanism.

The housing may have a body carrying the blade magazine and the transport mechanism, the body being formed in two longitudinally spaced apart sections, each section of the housing having interlocking engagement members adjacent a front end of the housing, and the housing further having an annular securing member for securing the laterally spaced apart housing sections together around the longitudinally spaced apart housing sections adjacent a rear end of the housing.

The ring mount may have a rear end cap rotatably mounted thereon and connected in a relatively non-rotating manner to the cartridge, whereby the rear end cap may be rotated by hand to rotate the cartridge to allow removal of used blades and attachment of new blades relative to the arm of the delivery mechanism.

The conveyor housing may also have a bearing surface extending forwardly and rearwardly from the arm to prevent rotation of the blade about the arm when the arm is in the operative position or when the blade is moved between the magazine and a forward position.

In addition, the housing may have a bulbous rear portion carrying the blade magazine, the bulbous rear portion being ergonomically sized to be comfortably held by a hand.

An embodiment of the invention is described below, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a utility knife according to one embodiment of the present invention;

FIG. 2 is an exploded view of the tool of FIG. 1;

FIG. 3 is a fragmentary view taken in the direction of the arrows in FIG. 2 illustrating the adjacent interlocking of the housing portions with the front end of the housing;

fig. 4 is a cross-sectional view taken along line 4-4 of fig. 2, illustrating the rear end cap in cooperation with the annular retainer ring at the rear end of the housing.

Fig. 5 is an enlarged perspective view of the blade magazine, wherein the transport member and the knife are also indicated by dotted outline lines for the sake of illustration.

FIG. 6 is a longitudinal cross-sectional view of the knife showing the blades in the magazine engaged for the feed mechanism;

FIG. 7 is a view similar to FIG. 6 showing the blade having been advanced to the operating position by the transport mechanism;

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7 illustrating the transport mechanism; while

Fig. 9 is a cross-sectional view taken along line 9-9 of fig. 6 showing the guide and transport mechanism in the housing.

Referring to the drawings, the utility knife 10 has a hand holdable housing 12 with a front end 14 and a rear end 16. The blade cartridge 18 is removably mounted within the housing 12 and is rotatable in a manner to be described below about an axis parallel to a longitudinal axis of the housing 12 extending from the front end 14 to the rear end 12. The magazine 18 has a series of radially and longitudinally extending circumferentially spaced slots 20 for independently receiving thin blades 22, the slots 20 being open at both ends. The blade 22 is of a conventional type and is trapezoidal in shape (see in particular fig. 7) with a lower cutting edge 24 meeting two inclined end edges 26, 26 to form sharp cutting points 30, 32 at each end. The upper blade edge 34 is parallel to the lower blade edge 24. The upper edge 34 has a recess 36 midway along its length, the recess 36 having a short initial flat portion 38 with parallel sides and a rounded portion 40 at the inner end of the flat portion 38.

The housing 12 also carries a slidable transport mechanism 42 which, as will be described in more detail below, has a manually engageable actuator 44 projecting therefrom and slidable longitudinally between rear and front positions shown in figures 6 and 7 respectively.

The blade magazine 18 has a rotatable body consisting of two main magazine parts 46, 48. The first portion 46 has a hub-like end 50 with a series of radially and longitudinally extending circumferentially spaced apart groove-forming fingers 52. Fingers 52 extend longitudinally from end 50 to an opposite end of first portion 46. The fingers 52 extend longitudinally beyond the hub end 50, with their free ends forming opposite ends 54 of the first pocket 46. The second pocket portion 48 has a hub-like end portion 56 with a series of radially and longitudinally extending circumferentially spaced second slot-forming fingers 58 extending longitudinally from this end portion 56 to an opposite end 60 of the second portion 48. The fingers 58 extend longitudinally beyond the hub end 56, while the free ends thereof define an opposite end 60 of the second pocket 48. The first and second fingers 52, 58 each have a groove 61 along a central portion of their radially outer surfaces, the grooves 61 extending in a circumferential direction.

The first pocket portion 46 and the second pocket portion 48 are combined by longitudinal movement of the first finger 52 between the second finger 58 to form a blade receiving slot 20 between each adjacent pair of the first and second fingers 52, 58. When assembled, the ends of the fingers 52 of the first pocket 46 slide over and support the hub-like end 56 of the second pocket 48. Similarly, the second finger 58 of the second pocket 48 slides over and supports the hub-like end 50 of the first pocket 46. When the cartridge 18 is fully assembled as described above, the hub-like end 50 of the first cartridge portion 46 abuts the hub-like end 56 of the second cartridge portion 48, as shown in fig. 6, and the circumferentially extending slots 61 in the fingers 52, 58 form a continuous circumferential slot substantially around the cartridge 18, i.e., interrupted only by the slit 20, see fig. 5.

The magazine is assembled by a blade retaining ring 62, the ring 62 having a circumferential gap 64. The ring 62 slides along the two assembled pockets 46, 48 from one end thereof until the ring 62 snaps into the circumferentially extending groove 60. Then loading one blade 22 at a time into the corresponding slot 20; the blade retaining ring 62 is moved circumferentially to position the gap 64 and the slot 20 loaded with the blade 22 in unison.

As shown in fig. 5, the circumferential width of the gap 64 in the blade retaining ring 62 is equal to the width between the blade receiving slots 20. The blade 22 is located in each slit 20 other than the one of the upper slits 20 in fig. 5. The upper end of each blade 22 projects slightly above the periphery of the pocket 18, and the retaining ring 62 passes through the circular recess 40 in each blade 22, thereby retaining the blade 22 within the slot 20 and with its lower cutting edge 24 slightly spaced from the hub-like ends 50, 56 of the first and second pocket portions 46, 48.

Each hub-like end 50, 56 has a longitudinally projecting stub shaft 66, 68, each having a square cross-section, while the blade retaining ring 62 has a radially outwardly projecting retaining member 70 positioned radially opposite the peripheral gap 64.

As shown more clearly in FIG. 2, the housing 12 is formed in two longitudinally separable sections 72, 74. The housing portions 72, 74 have an interlocking engagement adjacent the front end 14 of the housing 12, see fig. 2 and 3. As shown, this interlocking engagement is provided by a tongue/groove type connection, with the housing portion 72 providing a tongue 76 and the housing portion 74 having a groove 78 therein. To assemble the two housing portions 72, 74 together, a tongue 76 on the housing portion 72 slides from the rear end of the slot 78 into the slot 78 in the housing portion 74. The two housing portions 72-74 are mirror images of each other, except for the formation of the tongue 76 and groove 78 described above.

The rearward ends of the housing portions 72-74 each have external threads 80, 82 that combine to receive an internally threaded retaining ring 84 that is threaded into the threads 80, 82 to secure the rearward ends of the housing portions 72-74 together.

The retaining ring 84 has a rear end cap 86 rotatably mounted thereon, the end cap 86 having an annular shoulder that snaps into the rear end of the mounting ring 84 so that the end cap 86 is rotatably secured to the retaining ring 84.

The end cap 86 has a circumferential groove 90 rearward of the shoulder 88 that receives a tab 92 formed in the mounting ring 84. The circumferential groove 90 has a stop slot 94 on its bottom surface, indicated in fig. 2. The lower surface of the upper tab 92 of the mounting ring 84 has a needle 96 (fig. 4) projecting downwardly therefrom. The needle 96 is insertable into the slot 94 in the end cap slot 90 to securely position the end cap 86 in a predetermined position relative to the retaining ring 84 for a purpose to be described.

The conveyor 84 has a body member 100 with transverse wings 102, 104 that slide along the housing portions 72, 74 and longitudinally extending ridges 106, 108, respectively. A post 110 depends from the body member 100 and has a transversely extending arcuate blade carrying arm 112 at its end. The blade carrier arm 112 is movable into the gap 64 in the blade retaining ring 62 and has a similar cross-section to the ring 62 except that the lower surface 114 of the blade carrier arm 112 is flat and at a height that positions the lower surface 114 over the slots 60 in the fingers 52, 58 of the first and second pockets 46, 48.

Body member 100 also has a rearward extension 116 which carries a post 118. A coil spring 120 is disposed around and protrudes above the rod 118. The lower end of the coil spring 120 is supported by the extension 116 and the upper end of the coil spring 120 carries the hand engageable actuator 44. As shown, the upper end of the coil spring 120 extends into a recess 122 in the underside of the actuator 44. The actuator 44 has a pair of transverse projections 124, 126 which slide generally under longitudinally downwardly extending shoulders 128, 130 in the housing portions 72, 74, respectively. The housing portion 74 has four longitudinally spaced recesses 132, 133, 136, 138 extending from the shoulders 128, 130, and within each of these recesses the actuator 44 is biased by the coil spring 120 to lock the transport mechanism 42 into any one of four predetermined positions as will be described in greater detail below. The housing portion 72 has four similar recesses (not shown). The forward-most end of the body member 100 has a nose 140 shaped to match the configuration of the front end 14 of the housing 12 when the body member 100 is in its forward-most position, and the housing portions 72, 74 define an aperture 142 (see fig. 3) for receiving the nose 140.

The housing portion 74 has a vertically spaced pair of guides 144, 146 which guide the blade 22 as it is moved to its operative position as will be described in more detail hereinafter. The chassis 74 has similar guides 145, 147. Housing portion 72 also has a semi-circular recess 148 which, together with a similar recess 149 in housing portion 74, forms a bearing in which the forward stub shaft of cartridge 18 can rotate. The rotatable end cap 86 has a square recess 150 centrally located in its inner surface for receiving the rear stub shaft 68 of the cartridge 18 in relatively non-rotatable relation.

The housing portions 72, 74 have recesses 154, 156 at the rear ends of their lower edges forming a slot 158 extending forwardly from the rear end 16 of the housing 12 for receiving the protrusion 70 on the blade retaining ring 62, as will be described in greater detail below.

Before describing the operation of the utility knife, it should be noted that the two housing portions 72, 74 cooperate to provide the housing 12 with the bulbous rear portion 152 in which the pocket 18 is located, the bulbous rear portion 152 being sized and configured to be comfortably held by a person's hand.

In the case of a knife, the end cap 86 is disengaged from the housing 12 by inserting a suitable tool into the slot 87 of the retaining ring 84, and the cartridge 18 with the knife mounted thereon is then inserted into the rear end of the housing 12 with the forward stud 66 entering the bearing formed by the recesses 148, 149 in each of the housing portions 74, 72. It should be appreciated that stub shaft 66 is free to rotate in this bearing. The projections 70 on the blade retaining ring 62 enter the slots 158 in the bottom of the housing 12 and are thereby prevented from rotating. The retainer ring 84 has a slot 89 that mates with the slot 158 to allow the projection 70 to pass through the retainer ring 84. The end cap is then snapped back into the retaining ring 84.

The actuator point 44 is now depressed to release the projections 124,126 from the recesses 132 in the housing portion 74 and the corresponding recesses in the case portion 72, and the actuator 44 is then slid back to its final position, i.e., adjacent the rear end of the case 12, so that the blade carrier arms 112 on the body member move into the gaps 64 in the blade retaining ring 62, see fig. 5. In this position, the projections 124, 126 engage in a final recess 139 in the housing portion 74 and a corresponding recess in the housing portion 72, locking the feed mechanism 42 in this final or "retracted" position. The end cap 86 is then rotated through a "detent" position, i.e., one slot 94 is clear of the needle 96 on the tab 92 and the next slot 94 receives the needle 96, and the magazine 18 is rotated through an increment, i.e., the blade 22 is cleared from the retaining ring 62 onto the blade carrier arm 112, as shown in fig. 6 and 9. Finger grips 160 are provided on the end cap 86 to facilitate this rotation.

Actuator 44 is then slid forward and held in a forward-most position until projections 124, 126 reach within recess 132 of front end housing portion 174 of housing 12 and corresponding recesses of housing portion 72. During the above-described movement. The body member 100 of the transport mechanism carries the blade 22 forwardly out of its slot 20 to the operative position shown in fig. 7, where the front of the blade 22 projects from the front end of the housing 12. During this forward movement, the blade 22 is guided by the guides 144, 146 and 145, 147. If it is desired that the insert 22 protrude less, the actuator 44 may be engaged with one of the two more rearward positions defined by the recesses 136, 138 of the housing portion 74 and the corresponding recess in the housing portion 72. Should it be desired to temporarily retract the blade 22, the actuator may be moved back into the recess 138 of the housing portion 74 and the corresponding recess of the housing portion 72. It will be appreciated that the blade 22 is prevented from rocking by engaging the upper edge 34 of the blade 22 with the lower surface 162 of the body member 100 of the transport mechanism 42, see fig. 6 and 7.

To replace the leading end of the blade 22 when it becomes dull, for example, the actuator 46 is slid back to its final position, with the dull blade 22 returning to its original slot 20. Further incremental rotation by the end cap 86 then rotates the magazine 18 to the next number as shown above, thereby causing the dull blades 22 to be withdrawn from the blade carrier arms 112 onto the blade retaining ring 62. At this point, a new blade 22 is moved over the blade carrier arm 112 and can be moved to the working position by depression and forward movement of the actuator 44.

When all of the blades in the magazine 18 have been used, i.e., the magazine 18 has been rotated through 360, the magazine 18 can be removed from the housing 12 and reversed to allow access to the other end of the blade 22. For this reason, both ends of the slit 20 are naturally open. After which a new blade magazine 18 is used.

The advantages of the present invention will be readily appreciated from the above description of the preferred embodiments. Other embodiments of the invention will be readily apparent to those skilled in the art and the scope of the invention should therefore be determined by the appended claims.

Claims (16)

1. A blade holder including a manually graspable housing having a front end and a rear end, and a blade magazine removably mounted in the housing and rotatable about an axis parallel to a longitudinal axis of the housing extending from said front end to said rear end; the magazine having a series of radially and longitudinally extending circumferentially spaced blade receiving slots for respectively receiving thin blades having cutting edges at least at one end, each slot having an open front end to enable a blade therein to be removed from the magazine by forward movement of the front end through the slot;

said housing further carrying a slidable transport mechanism having a manually engageable actuator projecting from the housing, the actuator being slidable between forward and rearward positions, and a blade engaging arm in the housing, the actuator being positionable to a forward position to permit the blade carried by said arm to project from the forward end of the housing into an operative position, and movement of the actuator from the forward position to a rearward position to cause the blade to be withdrawn from the operative position into the housing and into the cartridge interior slot; the magazine can be rotated to remove a withdrawn blade from the arm of the transport mechanism and to position a new blade from the other slot onto the arm, in a subsequent movement being brought to the working position by the actuator.

2. The knife of claim 1 wherein said magazine includes first and second sections, said first section having a first end with a series of radially and longitudinally extending circumferentially spaced first slot forming fingers extending longitudinally from said first end to an opposite end of said first section; the second portion having a second end with a series of radially and longitudinally extending circumferentially spaced second slit forming fingers extending longitudinally from the second end to opposite ends of the second portion;

the first portion is combined with the second portion by longitudinal movement of the first fingers between the second fingers to provide a blade receiving slot between each adjacent pair of the first and second fingers, each slot being open at least at one end thereof to enable the blade in the slot to be withdrawn therefrom by the transport mechanism by longitudinal sliding movement therethrough via the forward ends of the slots.

3. The knife of claim 2, wherein the first finger of the blade magazine can have a front end slidably fitted over and supported by an end of the second portion, and the second finger can have a front end slidably fitted over and supported by an end of the first portion.

4. The knife of claim 2 wherein each of the first and second fingers has a radially outer surface with a circumferentially extending slot, said magazine further having a blade retaining ring surrounding the magazine itself except for the gap and located in the slots of the first and second fingers with a circumferential gap, the blade retaining ring being non-rotatably retained in the housing such that the circumferential gap coincides with the path of travel of the conveyor mechanism, thereby allowing the arm of the conveyor mechanism to enter the circumferential gap to remove a used blade from the arm and attach a new blade to the arm.

5. The knife of claim 4 wherein each slot of the magazine holds a blade having a recess in a radial edge thereof, and the blade retaining ring passes through the recess of each blade.

6. The cutter of claim 2 wherein at least one of said sections of said magazine has a stub shaft projecting longitudinally outwardly from one end thereof, and said housing has a manually rotatable portion capable of receiving the stub shaft in a relatively non-rotatable manner, whereby rotation of the manually rotatable portion of the housing causes removal of a used blade and attachment of a new blade relative to the arm of said transport mechanism.

7. The cutter of claim 1 wherein said housing has a body carrying the blade magazine and the feed mechanism, the body being formed in two longitudinally spaced sections, each section of the housing having interlocking engagement members adjacent a front end of the housing, and the housing further having an annular securing member for securing the laterally spaced housing sections together around said longitudinally spaced housing sections adjacent a rear end of the housing.

8. The knife of claim 7 wherein said annular fixture has a rear end cap rotatably mounted thereon and connected in a relatively non-rotating manner to said magazine, whereby rotation of the rear end cap by hand rotates the magazine to allow removal of used blades and loading of new blades relative to the arm of said feed mechanism.

9. The knife of claim 1 wherein the transport mechanism further has a bearing surface extending forward and rearward from the arm to prevent rotation of the blade about the arm when the arm is in the working position or when the blade is moved between the magazine and a forward position.

10. The knife of claim 1 wherein the housing has a bulbous rear portion carrying the blade magazine, the bulbous rear portion being sized to be comfortably held by a human hand.

11. A blade magazine, comprising: a body rotatable about a longitudinal axis and having forward and rearward ends, the body having a series of radially and longitudinally extending circumferentially spaced blade receiving slots for respectively receiving thin blades having a cutting edge at least at one end, each slot having an open forward end enabling the blade therein to be withdrawn through the forward end of the slot by forward movement.

12. The blade magazine as recited in claim 11, wherein the rotor comprises first and second portions; the first portion having a first end with a series of radially and longitudinally extending circumferentially spaced first slit-forming fingers extending longitudinally from said first end to an opposite end of said first portion; and the second portion having a second end with a series of radially and longitudinally extending circumferentially spaced second slit-forming fingers extending longitudinally from said second end to an opposite end of said second portion; said first portion being combined with said second portion by longitudinal movement of said first fingers between said second fingers to provide a blade receiving slot between each adjacent pair of said first and second fingers; at least one end of the slot is open to allow the blade in the slot to be withdrawn through the open end thereof.

13. The blade magazine of claim 12, wherein the first finger member has a first end slidably engaged with and supported by said end of the second section and the second finger member has a first end slidably engaged with and supported by said end of the first section.

14. A blade magazine according to claim 12 wherein each of the first and second fingers has a radially outer surface with a circumferentially extending slot, said magazine having a blade retaining ring with a circumferential gap around the magazine itself except for said gap and located in the slots of the first and second fingers.

15. A blade magazine according to claim 14 wherein each slot contains blades having a recess in the radially outer edge thereof and the blade retaining ring passes through the recess of each blade.

16. A blade magazine according to claim 12 wherein at least one of the magazine sections has a stub shaft projecting longitudinally outwardly from its end.