Knife

Abstract

A knife has a housing, a blade having a cutting edge and mounted on the housing with the edge extending transversely of a predetermined direction. An actuator is movable on the housing and pivots a blade guard on the housing about a guard axis for movement in the predetermined direction from a safety position in which the blade guard covers the cutting edge of the blade into a cutting position in which the blade guard is spaced from the cutting edge and the cutting edge is freely accessible and from the cutting position in a direction opposite the predetermined position into the safety position.

Claims

1. A utility knife comprising: an elongated housing defining a longitudinal axis; a blade holder pivotal on the housing about a holder axis extending transversely to the longitudinal axis of the housing between a cutting position and a safety position; a blade secured on the holder, pivotal therewith between the safety position and the cutting position, and formed with a cutting edge extending radially of the holder axis; a blade guard pivotal on the housing about a guard axis extending transversely to the longitudinal axis of the housing and offset from the holder axis, the blade guard being pivotal between a respective safety position shielding the cutting edge when in the blade holder is in the safety position and a respective cutting position spaced angularly about the guard axis from and exposing the cutting edge when the blade holder is in the cutting position; respective sets of meshing teeth on the guard and on the holder for synchronous and opposite pivoting of the guard and holder respectively about the guard and holder axes; an actuator displaceable on the housing between an actuated position and an unactuated position; the actuator is operatively engaged to the holder for moving the cutting edge and blade guard angularly apart respectively into the cutting positions on movement of the actuator between the unactuated and actuated positions; and spring means for urging the blade guard and blade holder respectively into the safety positions.

2. The utility knife defined in claim 1, wherein the holder and guard axes are parallel to each other.

3. The knife according to claim 1, wherein the actuator disengages from the holder on movement of the cutting edge from the cutting position away from the blade guard.

4. A knife comprising: a housing extending in a predetermined direction; a blade holder pivotal on the housing; a blade in the blade holder, having a cutting edge, and pivotal on the housing with the blade holder between a safety position and a first cutting position; an actuator movable on the housing and operatively connected to the blade holder for moving the blade holder from the safety position to the first cutting position; a blade guard pivotal on the housing from a respective safety position in which the blade guard covers the cutting edge of the blade when in the blade holder is in the safety position into a respective cutting position in which the blade guard is spaced from the cutting edge and the cutting edge is freely accessible when the blade holder is in the first cutting position and from the respective cutting position into the respective safety position; coupling means between the blade guard and the blade holder for synchronously pivoting the blade guard and the blade holder in opposite directions, whereby movement of the blade holder from the safety position into the first cutting position also moves the blade guard from the respective safety position into the respective cutting position; and a spring for pivotally biasing the blade guard and the blade holder respectively into the safety positions.

5. The knife according to claim 4, wherein the actuator disconnects from the holder on movement of the cutting edge from the first cutting position away from the blade guard.

6. The knife according to claim 4 further comprising a first coupling element movably coupled with the housing and movably coupled with the holder; and wherein the actuator is a handle with second coupling element that engages with the first coupling element to define the operative connection between the holder and the actuator.

7. The knife according to claim 6, wherein the coupling elements move out of engagement with each other by movement of the blade holder from the first cutting position into a second cutting position angularly offset from the first cutting position away from the safety position, thereby decoupling the handle from the blade guard.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Further advantages of the invention are disclosed with reference to the description of an embodiment shown in the drawings. Therein:

(2) FIG. 1 is a schematic sectional view of a first embodiment of the knife with a blade fixed to the housing, the handle unactuated, and the blade guard in a safety position,

(3) FIG. 2 shows, like FIG. 1, the knife with the handle in an actuated position and the blade guard in a cutting position,

(4) FIG. 3 shows, like FIG. 2, the knife with the coupling elements of an actuator separated from one another,

(5) FIG. 4 shows, like FIG. 3, the knife with the handle in the actuated position and the blade guard in the safety position,

(6) FIG. 5 shows a second embodiment of the knife with the blade movable on the housing and in a end position and the blade guard in the safety position,

(7) FIG. 6 shows, like FIG. 5, the knife with the handle in an actuated position, the blade guard in a first cutting position, and the blade in a first working position,

(8) FIG. 7 shows, like FIG. 6, the knife with the handle in the actuated position, the blade guard in a second cutting position, the blade in a second working position, and the coupling elements of an actuator separated from one another,

(9) FIG. 8 shows, like FIG. 7 with the handle in the actuated position and the blade guard in the safety position.

SPECIFIC DESCRIPTION OF THE INVENTION

(10) The knife according to the first embodiment as a whole is designated in FIGS. 1 to 4 with reference numeral 10. The same reference numerals in the different figures of the first embodiment designate corresponding parts.

(11) According to FIG. 1, the knife 10 has a housing 11 that forms a handle by which the knife 10 can be held by the user. A blade 12 is mounted on the housing 11. In this embodiment the blade 12 is fixed on the housing 11, and a tip of the blade 12 projects out of the housing 11. The blade 12 has a cutting edge 13 facing angularly and extending radially from a pivot axis a1. For the invention it is irrelevant whether the blade 12 is fixed or movable on the housing 11. According to an alternative embodiment, the blade could also be movable on the housing.

(12) A blade guard 14 is mounted on the housing 11 so as to pivot about the pivot axis a1 between a safety position and a cutting position and forms a pivot G1 with the housing 11. The blade guard 14 is a clip and, in the safety position shown in FIG. 1, fits around the blade 12 in such a way that it is inaccessible for a user, so that the user cannot be injured by it.

(13) A handle 15 is mounted on the housing 11 so as to pivot about a pivot axis a2 between an unactuated position and an actuated position and forms a pivot G2 with the housing 11. The end actuated position of the handle is designated below according to FIGS. 2, 3 and 4 as the “actuated position.” The handle 15 moves the blade guard 14 between the safety position and the cutting position shown in FIG. 2. The handle 15 is part of an actuator 16.

(14) In the illustrated embodiment the handle 15 is formed by a lever pivotal on the housing 11, although this is not important for the invention. In fact, according to an alternative embodiment, the handle 15 could also be formed by a slider.

(15) The handle 15 has an extension 17 with a cam 18. The cam 18 engages with an oblique surface 19 of a slide 20 inclined with respect to its directions of movement x1 and x2. The slide 20 is mounted in the housing 11 so as to be movable in the directions x1 and x2 between a rear position and a front position. A spring 21 is fastened with one end to the slide 20 and with the other end to the housing 11 and biases the slide 20 into a rear position shown in FIG. 1. The handle 15 is also biased into the unactuated position indirectly by the spring 21 via the contact between the slide 20 and the cam 18.

(16) A coupling lever 22 is pivotal on the slide 20 about a pivot axis a3 between an engaged position and a release position and forms a pivot G3 with the slide 20. The coupling lever 22 is biased into the engaged position of FIG. 1 by a spring 27 fastened with one end to the housing 11 and with another end to the coupling lever 22. A weight 24 is carried on the coupling lever 22. The weight 24 is in particular fastened to a free end 23 of the coupling lever 22. Furthermore, the coupling lever 22 is provided with a first coupling projection 25.

(17) The first coupling projection 25 engages a second coupling projection 28 of a coupling slide 29. The coupling projections 25 and 28 form a coupling 38. In the engaged position the coupling lever 22 is positioned in such a way that the first coupling projection 25 can engage the second coupling projection. In the release position the coupling projections 25 and 28 are disengaged.

(18) The coupling slide 29 is mounted in the housing 11 so as to be movable in the directions x1 and x2 between a rear position and a forward position. A spring 30 fastened with one end to the housing and with another end to the coupling slide 29 biases the slide 29 into the rear position.

(19) A first end 31 of a link 32 forms with the coupling slide 29 a pivot G4 having a pivot axis a4. A second end 33 of the link 32 forms with the coupling slide 34 a pivot G5 having the pivot axis a4.

(20) In order to carry out a cutting operation, the handle 15 is pivoted out of the unactuated position of FIG. 1 in the direction u1 into the actuated position of FIG. 2. In this case the cam 18 exerts a force F on the inclined surface 19. The force F has a component that acts in the direction x1, so that the slide 20 is moved against the force of the spring 21 out of the rear position of FIG. 1 in the direction x1 into the front position (see FIG. 2), and the cam 18 slides on the inclined surface 19 from a first point 35 to a second point 36. The coupling lever 22 pivotal on the slide 20 is also moved in the direction x1. The first coupling projection 25 of the coupling lever 22 engages the second coupling projection 28 of the coupling slide 29 so that it is also moved against the force of the spring 30 out of the rear position in the direction x1 into the forward position.

(21) When the coupling slide 29 is moved into the forward position, it pivots the blade guard 14 by the link 32 and the lever arm 34 in the direction w1 into the cutting position (see FIG. 2).

(22) The knife 10 has an automatic blade guard return movement. If, during cutting, the user should slide off the material to be cut, due to the sudden movement downward in the direction z the coupling lever 22 is pivoted because of the mass moment of inertia against the spring force of the spring 27 in the direction v1, and the first coupling projection 25 and the second coupling projection 28 move out of engagement (see FIG. 3) with each other. In order that the coupling lever 22 can pivot in the direction v1, a cutout 26 is provided on the slide 20. Then the coupling slide 29 is moved by the spring 30 into the rear position, thereby moving the blade guard 14 by the link 32 and the lever arm 34 in the direction w2 into the safety position (see FIG. 4), although the handle 15 is still in the actuated position. During movement into the safety position, the blade guard 14 is moved forward toward a side 37 of the blade 12 provided with the cutting edge 13.

(23) As the force on the handle 15 diminishes, the slide 20 is moved back by the spring 21 into the rear position and the handle 15 is also moved indirectly in the direction u2 into the unactuated position. The first coupling projection 25 of the coupling lever 22, which is biased by the spring 27 in the direction v2, moves again into engagement with the second coupling projection 28 of the coupling slide 29 (see FIG. 1).

(24) A second embodiment of the knife is shown in FIGS. 5 to 8. The knife according to the second embodiment is designated overall by the reference numeral 110. The same reference numerals in the different drawings of the second illustrated embodiment designate corresponding parts.

(25) The knife 110 has a housing 111. A blade holder 112 can pivot on the housing 111 between a first end position shown in FIG. 5, a first working position shown in FIG. 6, a second working position shown in FIG. 7 and a second end position shown in FIG. 8. The blade holder 112 forms with the housing 111 a pivot G2 having a pivot axis a2. A blade 113 with a cutting edge 114 is releasably held in the blade holder 112.

(26) A blade guard 115 forms with the housing 111 a pivot G1 having a pivot axis a1. The blade guard 115 can move between a first safety position shown in FIG. 5, a first cutting position shown in FIG. 6, a second cutting position shown in FIG. 7 and a second safety position shown in FIG. 8. In the first and second safety positions the blade guard 115 fits over a cutting edge 114 in such a way that the cutting edge 114 is inaccessible for a user. In the first cutting position the blade guard 115 is moved away from the cutting edge 114, so that the cutting edge 114 can be placed on the material to be cut and a cut can be made.

(27) The blade holder 112 and the blade guard 115 are coupled for joint movement. The blade guard 115 is in the first safety position when the blade holder 112 is in the first end position (see FIG. 5). When the blade holder 112 moves into the first working position, the blade guard 115 moves into the first cutting position (see FIG. 6), and when the blade holder 112 moves into the second working position, the blade guard 115 moves into the second cutting position (see FIG. 7). The blade guard 115 is in the second safety position when the blade holder 112 is in the second end position (see FIG. 8).

(28) The coupling in terms of movement takes place for example by teeth 116 of the blade holder 112 that mesh with teeth 117 of the blade guard 115. In this way the blade holder 112 and the blade guard 115 pivot in opposite directions. This means that when the blade holder 112 pivots in the direction u1 the blade guard 115 pivots in the direction w1, and when the blade holder 112 pivots in the direction u2 the blade guard 115 pivots in the direction w2.

(29) A handle 118 is part of an actuator mechanism 122 and is provided for actuation of the blade holder 112 as well as the blade guard 115. The handle 118 is movable in a straight line in the directions x1 and x2 between an unactuated position shown in FIG. 5 and an actuated position shown in FIG. 6. The handle 118 is movable out of the unactuated position in the direction x1 into the actuated position. The handle 118 is movable out of the actuated position in the direction x2 into the unactuated position. The handle 118 is biased into the unactuated position for example by a restoring force of a spring 125 only indicated schematically by a broken line. The spring 125 is fastened to the housing 111 and to the handle 118.

(30) According to an unillustrated alternative embodiment the handle could also be formed by a lever pivotal on the housing 111 as in the first embodiment.

(31) The handle 118 has a first coupling element 119 in the form of a resiliently deformable arm. The first coupling element 119 is for example formed on the handle 118 or is connected to the handle 118. A free end of the first coupling element 119 can be moved into engagement with a second coupling element 120 and can also be separated therefrom. The second coupling element 120 is formed by part of an actuating element 121 of the actuator mechanism 122.

(32) The actuating element 121 is formed by a lever forming on a guide 123 a pivot G3 having a pivot axis a3. The guide 123 is movable in the housing 111 in the directions x1 and x2. The pivot axis a3 is not movable relative to the guide 123, but is movable relative to the housing 111. According to an alternative embodiment that is not illustrated, for example no guide 123 is provided and a pin of the pivot G3 forming the pivot axis a3 is received in a guide slot of the housing 111, and the guide slot allows movement of the pin in the directions x1 and x2 as well as pivoting of the actuating part 121 around the pin.

(33) In this embodiment the actuating element 121 is formed by a two-armed lever. The actuating element 121 has a first lever arm 124 and a second lever arm itself forming the second coupling element 120. A fourth pivot G4 with a pivot axis a4 is formed between the actuating element 121, in particular the first lever arm 124 of the actuating element 121, and the blade holder 112. The pivot G4 is eccentric to the pivot axis a2 on the blade holder 112 so that movement of the actuating part 121 in the direction x1 pivots the blade holder 124 in the direction u1.

(34) In the starting position of the knife of FIG. 5, the first coupling element 119 and the second coupling element 120 are in engagement. According to an alternative embodiment that is not illustrated, after a short movement of the handle 118 out of the unactuated position in the direction x1 the first coupling element 119 and the second coupling element 120 come into engagement, whereas in the unactuated position of the handle 118 they are still disengaged.

(35) When the user moves the handle 118 in the direction x1 out of the unactuated position shown in FIG. 5 into the actuated position of FIG. 6, the actuating element 121 pushes the guide 123 in the direction x1 by the pivot G3. In this case the actuating part 121 pivots the blade holder 112 about the pivot G4 in the direction u1 into the first working position of FIG. 6. The engaged tooth systems 116 and 117 force the blade guard 115 to pivot in an opposite direction of rotation to the blade holder 112 in the direction w1 into the first cutting position that is shown in FIG. 6. Moreover, due to the pivoting of the blade holder 112 the actuating element 121 is also pivoted in the direction p2, and the first coupling element 119 is deflected by its resiliently restoring force in direction y1.

(36) If, while in the position of FIG. 6, the blade 112 is placed on the material to be cut, a resulting force F on the blade pivots the blade holder 112 in the direction u1 into the second working position and pivots the blade guard 115 in the direction w1 into a second cutting position of FIG. 7. In this case the actuating element 121 is pivoted further in the direction p2 into the position of FIG. 7, and the first coupling element 119 and the second coupling element 120 are released from one another. After release of the coupling elements 119 and 120, the first coupling element 119 is moved back by its resilient restoring force in the direction y2 into its starting position (see FIG. 7).

(37) After the coupling elements 119 and 120 have been separated from one another, the blade holder 112, which is biased into the rest or safety position by a spring 126 (only shown schematically in part in FIG. 8), can pivot back in the direction u2 into the second end position, even if as shown in FIG. 8 the handle 118 is in the actuated position. Because of movement of the blade holder 112 in the direction u2, the blade guard 115 is pivoted in the direction w2 into the second safety position and the actuating element 121 is pivoted about the pivot axis a3 in the direction p1. Moreover, the guide 123 is moved back in the direction x2. As soon as the handle 118 is released by the user, it is moved by the force of the spring 125 into the unactuated position of FIG. 5. In this case the coupling elements 119 and 120 are brought into engagement again.