Knife holder for snap-off blades, especially for snap-off hook blades

Abstract

knife holder (1) for snap-off blades (2), in particular for snap-off hook blades, comprising - a handle body (6), - a blade guide channel (8) formed in or on the handle body (6) and elongated along a blade displacement direction (10), - a blade guide slide (20) which is movable in the blade guide channel (8) and which is designed to be positively coupled to a snap-off blade (2) in the intended operating state in the blade displacement direction (10), - a rocker arm (40) which is pivotably coupled to the blade guide slide (20) about a rocker axis (42), - a ratchet rail (30) which is parallel to and along the blade guide channel (8) and is fixed to it, and - a locking device (54), wherein the locking rocker (40) has a locking pin (48) which engages in one of several locking pockets (34) of the locking rail (30) in a designated locking position, and wherein the locking device (54) has an actuating element (56) which is adjustable between a locking position and an unlocking position, wherein, when the actuating element (56) is arranged in the locking position, the locking rocker (40) is secured in its locking position against pivoting into a release position.

Description

[0001] The invention relates to a knife holder for snap-off blades, in particular for snap-off hook blades. Preferably, this knife holder, especially in combination with a corresponding snap-off blade, forms a so-called carpet knife.

[0002] Snap-off blades have long proven their worth in both professional and DIY applications for various cutting tasks. The advantage of snap-off blades lies in the quick and easy way they provide a sharp edge. Unlike knives with a conventional blade that requires sharpening – a process that demands time and experience – here, only the dulled portion of the blade snaps off along a predetermined line. Once a snap-off blade is worn out, the entire blade is replaced. Various knife holders are available for this purpose. These are often referred to as utility knives or, borrowed from English, "cutter knives" due to their frequent use in this field.The latter traditionally have straight blades, while utility knives were also frequently used with so-called hook blades, which, unlike snap-off blades, were often retractable and extendable within a relatively robust blade holder. Nowadays, however, snap-off hook blades are also available that can be used in conventional utility knife handles.

[0003] Especially with hook blades, a comparatively high force acts in the direction of blade extension during cutting. This also occurs with straight blades, for example, when cutting deep material with high friction (e.g., in a foamed material such as expanded polystyrene).

[0004] Conventional carpet knives or utility knives with snap-off blades are usually not adequately protected against such linear pulling forces. Often, the only locking mechanisms used are those that rely solely on friction or clamping the blade to the handle. However, with sufficiently high pulling forces, the blade can still be pulled out of the handle. This results in extra work, as the blade must first be manually removed from the material being cut and either disposed of or reinserted into the handle.

[0005] The invention is based on the objective of providing an improved method of securing a snap-off blade against unwanted removal from a handle.

[0006] This problem is solved according to the invention by a knife holder according to the claims of claim 1. Further advantageous and partly inventive developments of the invention are set out in the dependent claims and the following description.

[0007] The knife holder according to the invention is designed and intended for holding and guiding snap-off blades, in particular snap-off hook blades. For this purpose, the knife holder has a handle body and a blade guide channel formed in or on the handle body and extending along a blade displacement direction. The knife holder also has a blade guide slide that is slidable in the blade guide channel and is designed to be positively coupled to a snap-off blade in the blade displacement direction when in its intended operating state. Furthermore, the knife holder has a locking rocker that is pivotably coupled to the blade guide slide about a rocker axis, and a locking rail that runs parallel to and along the blade guide channel and is fixed to it. Finally, the knife holder has a locking device.The locking rocker has a locking pin that, in its intended locking position, engages in one of several locking pockets of the locking rail. Advantageously, this results in a positive-locking positioning and fixation (locking) of the blade guide slide in the blade guide channel. The locking device has an adjusting element that is adjustable between a locking position and an unlocking position. When the adjusting element is in the locking position, the locking rocker is secured in its locked position against pivoting into a release position.

[0008] Due to the features described above, the blade holder is particularly well secured against the blade shifting from its intended operating position. The blade is secured in its operating position by the interaction of the positive-locking coupling between the blade and the blade guide carriage, as well as by the interaction of the blade guide carriage and the locking rocker. The locking pin of the locking rocker engages in the corresponding detent pocket when in its detent position, thus positively locking the blade guide carriage in the appropriate position along the blade's direction of travel. Additionally, the locking rocker can be advantageously secured against unintentional movement in its release position by the locking mechanism. A positive locking mechanism thus increases the force required for movement in a simple and effective manner, without the need for actively applying a clamping force.

[0009] The term "positive locking" or "positive locking connection" between at least two interconnected parts is understood here and in the following to mean, in particular, that the cohesion of the interconnected parts is achieved, at least in one direction, by a direct interlocking of the contours of the parts themselves or by an indirect interlocking via an additional connecting element. The "blocking" of mutual movement in this direction is thus due to the form.

[0010] According to a suitable design, the detent pockets of the detent rail are arranged successively parallel to the blade displacement direction.

[0011] Preferably, the detent pockets define discrete ejection positions. In particular, the detent pockets are formed by preferably rectangular, especially square, recesses in a web.

[0012] According to another advantageous embodiment, the blade guide channel is open along the blade displacement direction, i.e., particularly along one longitudinal side. For example, the blade guide channel is roughly U- or C-shaped in cross-section. The locking rocker is accessible on the outside of the blade guide channel for manual adjustment between the locking position and the release position. In particular, the locking rocker can therefore be manually operated and adjusted.

[0013] According to a preferred embodiment, the locking rocker is spring-loaded towards the locking position. This enables, in particular, automatic adjustment of the locking rocker into the locking position and thus automatic "locking" of the blade in its intended operating position (extended position). This represents a particularly user-friendly design.

[0014] According to a practical design, the rocker axis of the locking rocker is aligned parallel to the blade movement direction. In this case, the locking rocker must therefore be "operated," i.e., tilted, perpendicular to the blade movement direction.

[0015] According to a preferred embodiment, the actuating element of the locking device is formed by a screw. This screw is guided by a lever arm of the locking rocker opposite the detent pin (and thus also the detent rail) via the rocker axis. In particular, a thread for the screw is also provided in this lever arm, for example, cut into a corresponding bore or introduced by means of a threaded insert. In its locking position, the screw is screwed by the lever arm against a counter surface in or on the blade guide channel. The screw thus forms an adjustable stop for the locking rocker, preventing it from tilting when the screw is screwed into the lever arm for intended locking and rests against the counter surface.

[0016] Alternatively, within the scope of the invention, it is also conceivable that the locking device, as an actuating element, comprises a type of rail which is lifted and positioned against the lever arm described above from an underside of the locking rocker. For example, in this case, the locking device can have an eccentric which can be operated, for example, by means of a lever or the like, and which, when adjusted, lifts the aforementioned rail against the lever arm.

[0017] In a preferred embodiment, the locking rail partially covers the blade guide channel. In particular, the locking rail forms a kind of overhanging edge to the blade guide channel. Specifically, the aforementioned counter surface for the screw is formed on a web that extends across the longitudinal opening of the blade guide channel opposite the locking rail and also partially covers the blade guide channel.

[0018] Advantageously, the blade guide slide is guided slidably between a base (in particular, a base opposite the longitudinal opening) of the blade guide channel and the locking rail, as well as, in particular, the aforementioned web that supports the counter surface for the screw. In cross-section, the blade guide channel is thus roughly C-shaped, so that the blade guide slide – and therefore also the blade held on it – is guided within the C.

[0019] According to a manufacturing-advantageous embodiment, the locking rail is injection-molded from plastic, for example from polyamide, polypropylene, a polycarbonate-acrylobutadiene styrene block polymer (PC-ABS), or the like. Preferably, the locking rail is formed in one piece, particularly monolithically (i.e., from the same material and in a single process step), with the handle body.

[0020] In a practical embodiment, the knife holder has a knife guide plate that is coupled to the handle body at an oblique angle to the blade movement direction. "Oblique" here and in the following refers specifically to an angle between 0 and 90° to the blade movement direction. Optionally, the knife guide plate has two contact surfaces aligned at right angles to each other, with the blade guide channel being oriented such that the blade, guided and extended within it, intersects the point where the two contact surfaces meet. This allows the knife holder, which in combination with the snap-off blade forms a carpet knife, to be advantageously used for cutting flooring in a corner between the floor and wall, whereby the guide plate can be used to press the flooring into the corner and simultaneously cut it within the corner.

[0021] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing schematically and exemplarily shows: Fig. 1. A knife holder with a snap-off blade in a perspective view, Fig. 2. The knife holder in a side view, Fig. 3. The knife holder in a top view, and Fig. 4 in a partial section view IV-IV according to Fig. 2 a blade guide channel and a locking rocker for securing the snap-off blade.

[0022] Corresponding parts in all figures are always marked with the same reference symbols.

[0023] In Fig. Figures 1-3 schematically depict a knife holder 1 for a snap-off blade 2 in various views. The knife holder 1, together with the snap-off blade 2 held on it, forms a carpet knife 4. The carpet knife 4 has a handle body 6 on which an elongated blade guide channel 8 is formed. The longitudinal extent of the blade guide channel 8 runs along a blade displacement direction 10.

[0024] The blade displacement direction 10 is inclined relative to a guide plate 12 of the knife holder 1. The latter has two contact surfaces 14 that are at right angles to each other. The snap-off blade 2 is guided in the blade guide channel 8 such that, in an extended state, the snap-off blade 2 at least approximately overlaps the intersection of the two contact surfaces 14, i.e., is arranged in particular in line with an edge 16 between the two contact surfaces 14. Furthermore, the blade displacement direction 10 is inclined at an oblique angle, here approximately 30 to 40 degrees, to the edge 16.

[0025] To prevent the snap-off blade 2 from being pulled out of the blade guide channel 8 during intended use, the blade holder 1 has a locking device which is described in more detail below.

[0026] For guiding and moving the snap-off blade 2, the knife holder 1 has a blade guide slide 20, which is slidably mounted and guided in the blade guide channel 8 along the blade displacement direction 10. In its intended operating state, the blade guide slide 20 is positively coupled to the snap-off blade 2 in the blade displacement direction 10. For this purpose, the blade guide slide 20 has a retaining pin 22, which in its intended operating state (see figure) Fig. 1 and Fig. 2) engages in a corresponding recess in the snap-off blade 2.

[0027] The locking device has a locking rail 30 which projects over the blade guide channel 8 as a kind of bridge or edge (cf. Fig. 4) Opposite the locking rail 30, a further web 32 projects over the blade guide channel 8. The blade guide carriage 20 is slidably guided in the blade guide channel 8 in the blade displacement direction 10 beneath the locking rail 30 and the web 32.

[0028] The ratchet rail 30 has a plurality of “ratches”, specifically ratchet pockets 34, along its longitudinal extent, which runs parallel to the blade guidance direction 10, here in the form of rectangular, specifically approximately square, recesses.

[0029] The knife holder 1, specifically the locking device, also has a locking rocker 40. This is coupled to the blade guide carriage 20, but is pivotable relative to it about a rocker axis 42 between a locking position and a release position and is accessible from the outside to the blade guide channel 8. The locking rocker 40 has two sections, designated as lever arms 44 and 46, which are opposite each other across the rocker axis 42 (see figure). Fig. 4) On the lever arm 44, which faces the locking rail 30, the locking rocker 40 carries a locking pin 48. This is designed to be complementary or at least corresponding to the locking pockets 34, so that when the locking rocker 40 is in the locking position, the locking pin 48 engages in one of the locking pockets 34 and thus locks the blade guide slide 20 and consequently also the snap-off blade 2 in the corresponding insertion position (extension position).

[0030] The locking rocker 40 is further pre-tensioned to the blade guide slide 20 by means of a spring, specifically a C-shaped clamp spring 50, so that the locking rocker 40 is spring-loaded in its locking position. Therefore, to move the snap-off blade 2, the locking rocker 40 must be actively (manually) tilted (pivoted) from the locking position to a release position. This is done by pressing on the lever arm 46 opposite the locking rail 30. The rocker axis 42 runs parallel to the blade movement direction 10. Thus, the locking rocker 40 tilts perpendicular to the blade movement direction 10 around the rocker axis 42 towards the rib 32. This lifts the locking pin 48 out of the corresponding locking pocket 34 and the blade guide slide 20 can be moved. Once the desired operating position (extension position) is reached, the pressure can be released from the lever arm 46 and the locking rocker 40 tilts back towards its locking position.If the manually set position of the snap-off blade 2 is such that the locking pin 48 rests between two locking pockets 34 on the locking rail 30, the locking pin 48 can be brought into alignment with the locking pocket 34 in front or behind by a slight movement of the blade guide slide 20 and "snap" into it.

[0031] To prevent the locking rocker 40 from unintentionally releasing from its detent position, the blade holder 1 has a locking device 54. This device has an actuating element that can be manually moved into a locking position and an unlocking position. In the locking position, the actuating element prevents the locking rocker 40 from tilting into its release position, so that the detent pin 48 can no longer be lifted out of the corresponding detent pocket 34.

[0032] Specifically, the actuating element is formed by a screw 56 with a manually operated head 58. The screw 56 is guided by the lever arm 46, which faces away from the detent rail 30. For simplified manufacturing, a threaded bushing, here a nut 60, is incorporated into the lever arm 46, specifically on its underside (e.g., glued in or injection-molded). However, an internal thread can also be directly integrated into the lever arm. In this embodiment, the screw 56 is screwed through the nut 60. The nut 60 is arranged such that when the screw 56 is screwed deeper into the nut 60, it comes to rest against an upper surface of the web 32 (which forms a counter or stop surface for the screw 56) (locking position). This prevents the detent rocker 40 from pivoting towards its release position. Optionally, this also results in the detent rocker 40 being clamped against the detent rail 30.To adjust the snap-off blade 2, the screw 56 must first be unscrewed far enough from its locking position so that the locking rocker 40 can be tilted sufficiently to lift the locking pin 48 out of the locking pocket 34 (unlocking position of the screw 56). Thus, the locking rocker 40 cannot be unintentionally actuated – provided the screw 56 is in the locking position – and the snap-off blade cannot be released.

[0033] In the present embodiment, the handle body 6 and the ratchet rail 30 are manufactured in one piece from plastic, for example by injection molding.

[0034] According to an alternative embodiment, not shown in detail, a screw is provided which passes through the blade guide slide 20 and clamps it against a base (or bottom) of the blade guide channel 8 when screwed in. In this case, however, actuation of the locking rocker 40 would still be possible.

[0035] The subject matter of the invention is not limited to the embodiment described above. Rather, further embodiments of the invention can be derived by a person skilled in the art from the above description. Reference symbol list 1 knife holder 2 snap-off blades 4 carpet knives 6 handle bodies 8 blade guide channel 10 Blade displacement direction 12 Guide plate 14 Plant area 16 edge 20 blade guide slides 22 retaining pins 30 ratchet rail 32 Bridge 34 Rest pockets 40 Rest rocker 42 rocker axle 44 Lever arm 46 Lever arm 48 locking pins 50 clamp springs 54 Locking device 56 screw 58 heads 60 mother

Claims

[1] Knife holder (1) for snap-off blades (2), in particular for snap-off hook blades, comprising - a handle body (6), - a blade guide channel (8) formed in or on the handle body (6) and elongated along a blade displacement direction (10), - a blade guide slide (20) which is movable in the blade guide channel (8) and which is designed to be positively coupled to a snap-off blade (2) in the intended operating state in the blade displacement direction (10), - a rocker arm (40) which is pivotably coupled to the blade guide slide (20) about a rocker axis (42), - a ratchet rail (30) which is parallel to and along the blade guide channel (8) and is fixed to it, and - a locking device (54), wherein the locking rocker (40) has a locking pin (48) which engages in one of several locking pockets (34) of the locking rail (30) in a designated locking position, and wherein the locking device (54) has an actuating element (56) which is adjustable between a locking position and an unlocking position, wherein, when the actuating element (56) is arranged in the locking position, the locking rocker (40) is secured in its locking position against pivoting into a release position. [2] Knife holder (1) according to claim 1, wherein the detent pockets (34) of the detent rail (30) are arranged successively parallel to the blade displacement direction (10). [3] Knife holder (1) according to claim 1 or 2, wherein the blade guide channel (8) is open along the blade displacement direction (10), and wherein the locking rocker (40) is accessible on the outside of the blade guide channel (8) for manual adjustment between the locking position and the release position. [4] Knife holder (1) according to one of claims 1 to 3, wherein the detent rocker (40) is spring-loaded in the direction of the detent position by means of a spring (50). [5] Knife holder (1) according to one of claims 1 to 4, wherein the rocker axis (42) of the rocker arm (40) is aligned parallel to the blade displacement direction (10). [6] Knife holder (1) according to one of claims 1 to 5, wherein the actuating element of the locking device (54) is formed by a screw (56) which is guided by a lever arm (46) of the locking rocker (40) opposite the locking pin (48) via the rocker axis (42), wherein the screw (56) in the locking position is screwed by the lever arm (46) against a counter surface in or on the blade guide channel (8). [7] Knife holder (1) according to one of claims 1 to 6, wherein the ratchet rail (30) partially covers the blade guide channel (8). [8] Knife holder (1) according to claim 7, wherein the blade guide slide (20) is guided slidingly between a base of the blade guide channel (8) and the locking rail (30), and in particular a web (32) running opposite and parallel to the locking rail (30) and carrying the counter surface for the screw (56). [9] Knife holder (1) according to any one of claims 1 to 8, wherein the ratchet rail (30) is injection molded from plastic, in particular in one piece with the handle body (6). [10] Knife holder (1) according to one of claims 1 to 9, comprising a knife guide plate (12) which is coupled to the handle body (6) at an oblique angle to the blade displacement direction (10).

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