EP0882553B1 - Knife - Google Patents

Description

The invention relates to a knife according to the Preamble of claim 1.

DE 36 22 342 A1 discloses such a safety knife, a so-called cardboard knife, known which is used for cutting packaging boxes becomes.

The main features of the knife according to the DE 36 22 342 A1 allow the following functionality:

A translatable blade carrier is against a restoring force, namely against a spring restoring force, by means of an actuation area, which represents a push handle handle the knife housing can be extended and into the cutting position the interchangeable steel blade he picked up movable. As long as the knife blade is in Engagement with the material to be cut (carton) the friction between the knife blade and the material to be cut, so the cutting reaction force, making sure that the blade carrier against the restoring force of a tension spring in its extended operating position remains. As soon as the Cutting reaction force is less than the restoring force the tension spring, the latter pulls the one with the knife blade provided blade carrier in the retraction direction in its protective position (starting position) within the Knife housing back.

The retraction or retraction of the blade carrier but only happens when the operating hand Let go of the push handle handle. With the well-known safety knife according to DE 36 22 342 A1, it is on not wanted, but still possible, by continuously operating the push handle handle Blade holder in its extended cutting position detained so that accidental injuries Sliding of the knife from the material to be cut cannot be excluded are.

Starting from the knife described above According to DE 36 22 342 A1, the invention has the object based on the well-known knife in terms of its Improve safety function.

The invention solves this problem in that the Operating handle from one relative to the blade carrier movable separate actuating part is formed, which counter to the extension movement of the blade carrier with a separate restoring force, e.g. with a separate spring restoring force, is loaded that Blade carrier and actuating part in their starting position by a primary coupling element of the actuating part or the blade carrier and by a corresponding secondary coupling element of the Blade carrier or the actuating part only in the direction of extension the blade carrier is motion-coupled to be carried along, however in the entry direction of the blade holder are disengaged from each other that the movement of the Operating part limited in the sense of extension of the blade carrier is, and that the blade carrier an additional Relative movement in the extension direction is permitted, which the two coupling elements out of engagement with each other added.

In comparison to the safety knife described at the beginning according to DE 36 22 342 A1, it is in accordance with the invention Safety knife at first essential, that the operating handle from a relative to Blade carrier movable separate operating part is formed. Both the blade carrier and the separate one Actuating part are in the invention Knife with a separate force, preferably with a separate spring force, in their starting position reset load. That is the invention Actuating part against the extension movement of the Blade carrier resiliently loaded with a separate spring force.

Another remarkable peculiarity of the invention Safety knife is that Blade carrier and actuator in their reset or retracted starting position a primary coupling element of the actuating part or of the blade holder and by a corresponding secondary Coupling element of the blade carrier or Actuating part only in the direction of extension of the blade carrier are coupled with movement, but in the direction of entry the blade carrier out of engagement with each other are.

This peculiarity is given according to the invention their essential further education meaning that the movement of the operating part in the direction of extension of the blade carrier is limited, however, during the blade carrier an additional relative movement in the extension direction allowed is. This additional relative movement offset the two coupling elements out of engagement with each other.

This means that when the actuating part moves (which, for example, has a push handle handle can have) in the sense of extension of the blade carrier the latter because of the motion coupling between the two coupling elements towards the material to be cut is advanced until the movement of the operating part stopped for example by a stop becomes. As soon as the knife blade into the material to be cut has penetrated and the pulling cutting movement starts, tries the cutting reaction force, the knife blade (thus also the blade carrier) in the material to be cut to record what the mentioned additional relative movement of the blade carrier in the extending direction.

This additional relative movement is e.g. to used, the secondary coupling element of the blade carrier out of engagement with the primary coupling element to move the actuating part, whereby the first existing, one-sided in the direction of extension of the blade carrier existing motion clutch is disconnected. The This changes the cutting position of the blade holder not, at least not as long as the cutting work continues, and the cutting reaction force tries to hold the knife blade in the material to be cut.

But as soon as the cutting is finished, what even in the event of accidental sliding off the material to be cut the case is, the blade holder of the him separately assigned spring restoring force in its Protective position, i.e. to its starting position, moved back. This back movement of the blade carrier in its starting position occurs even when the Operating hand should try the actuator by permanent actuation in the direction of extension of the blade holder to charge.

The definition "the movement of the operating part in the sense of extension of the blade carrier "is to be defined that the shape, shape and direction of this movement are indifferent if only the movement of the actuating part the movement of the blade carrier in the direction of extension causes.

A simple design of the knife according to the invention is in any case due to a translational rectilinear To achieve movement of the moving part.

A variant of the knife according to the invention can in a translationally curved movement of the actuating part consist.

As mentioned earlier, the movement of the operating part in the direction of extension of the blade carrier limited in a simple manner by a stop, the expediently forms the knife housing.

In a further embodiment of the invention the common movement of the actuator and the Blade holder in the exit sense of the latter one Switching movement prepared, by means of which the two Coupling elements are separable. Advantageous this happens so that the two coupling elements separable from each other across their trajectories are.

In particular, the switching movement can be prepared that the trajectories of the two Coupling elements or the movement paths of blade carriers and actuating part including those assigned to them Coupling elements run differently.

An advantageous way to prepare the switching movement consists in the use of a backdrop control, which in particular the actuator and the Knife housing can be assigned.

According to a preferred embodiment is at least one slot or at least one Guide groove with a respective assigned guide pin provided, the longitudinal course of the slot slot or the guide groove in the direction of the actuating part with respect to the direction of extension of the blade carrier diverges.

One embodiment can be that the link slot or the guide groove along one arranged transversely to a main surface of the knife blade Level extends. Another advantageous embodiment e.g. in that the backdrop slot or the guide groove along an in or parallel arranged to a main surface of the knife blade Extend level.

Another embodiment variant according to the invention consists in that the assigned to the actuating part Link control two link slots or guide grooves with two corresponding guide pins for Has generation of the switching movement. Is expedient the respective link slot or the guide groove formed by the knife housing while the respective Guide pin is formed by the actuating part.

A particularly essential embodiment of the invention is that the switching movement to Preparatory separation of the two coupling elements initially just a potential spring energy generated that only in the course of the additional relative movement of the blade carrier effective in the direction of extension becomes.

That is from the joint movement of the actuating part and blade carrier derived a movement which serves to charge a spring element. As soon as the one caused by the cutting reaction force additional extension path of the blade carrier a certain Has reached dimension, the two coupling elements disengaged so that the potential previously generated Spring energy is capable of a separating movement bring about, at least on a coupling element relates and both coupling elements from each other distant. The distance is done in such a way that those stored by the blade carrier and operating part two coupling elements move past each other can, if the cutting reaction force in one reduced to such an extent that the spring return force in is able to retract the blade carrier into its Starting position to move. On the other hand, the Distance between the two coupling elements also Possibility to create that regardless of position the blade carrier the released actuator of the spring restoring force assigned to it in its starting position can be moved back.

In a further embodiment of the invention, one is of the two coupling elements from a recess and the other of the two coupling elements with one the recess lockable projection of a pressure transmission element educated.

The pressure transmission element (or more generally: Power transmission element) can, for example, by a link-controlled and / or spring-loaded jack (Pressure pawl or pull pawl) are formed, which too Start of the additional relative movement of the blade carrier disengaged from the recess in the direction of extension becomes. Basically, it is the same whether the transmission element the actuating part or the recess Blade carrier or in reverse the blade carrier or are assigned to the actuating part.

A simple safe uncomplicated design is given that the pressure transmission element a one side clamped buckling bar forms its movable free end the lead as primary or secondary Coupling element, which with a Recess as a secondary or primary coupling element interacts. The invention also has the Possibility provided that already in the free buckling bar a particularly effective spring force integrated is by making the free buckling bar from a spring metal, in particular from spring steel.

This also applies to certain applications Choosing alternative can be that the Buckling bar the blade carrier or the actuating part is integrally formed and in particular from one plastic has elastic properties.

A particularly practical one according to the invention Embodiment is that blade carriers and Actuator side by side in one to a main surface the knife blade parallel or inclined plane are arranged.

In this context, it is expedient for the actuating part to be designed so that this on a Long side one the blade carrier on its narrow side overarching approach, which at its the inner side facing the narrow side of the blade carrier forms one or the other coupling element, while the narrow side of the blade carrier is the other or that carries a coupling element.

A further development according to the invention exists in that the push handle handle on the above-described approach attached with one long side, in particular is integrally connected, such that the actuating part a total of one encompassing the blade carrier C-shaped cross section.

Fig. 1 eine Ansicht auf die eine Schieberbetätigungshandhabe zeigende Hauptfläche eines Sicherheitsmessers, Fig. 2 das Sicherheitsmesser gemäß Fig. 1 in einer axialen Schnittansicht,

die Fig. 3-7 unterschiedliche Betriebszustände des Messers gemäß den Fig. 1 und 2 und

Fig. 8 eine Ausführungsvariante analog zu der in Fig. 2 dargestellten Ausführungsform.

In the drawings, preferred exemplary embodiments according to the invention are shown more schematically,

1 is a view of the main surface of a safety knife showing a slide actuation handle, FIG. 2 shows the safety knife according to FIG. 1 in an axial sectional view, FIG.

3-7 different operating states of the knife according to FIGS. 1 and 2 and

Fig. 8 shows an embodiment variant analogous to the embodiment shown in Fig. 2.

A knife 10 has a knife housing 11, which from an upper housing shell 12 and from one lower housing shell 13 is composed. Both housing shells 12, 13 face each other with their hollow sides and are more appropriate in unspecified Attached to each other (e.g. detachable), for example by screwing or by clipping.

Inside the cavity 46 of the lower shell 13 is a knife blade 14 Blade carrier 15 along the central axis labeled M, in the extension direction x and in the retraction direction z, translationally displaceable. The a partially visible main area (broad area) of the Knife blade 14 bears the reference number 47.

The blade carrier 15 points in the area of the rear Handle extension 16 of the knife housing 11 a Guide extension 17 with a guide projection 18, which on the rectilinear inner surface 19 of the knife housing 11 is performed. On its two long sides the guide extension 17 each form a longitudinal recess 20, 21.

For example, where the guide extension 17 adjoins the connects the front area of the blade carrier 15, forms the blade carrier has an eyelet 22 into which the front End 23 of a tension spring 24 is hooked. The back End 25 of the tension spring 24 is on one of the knife housing 11 formed pin 26 attached.

The blade carrier 15 is partially from an operating part 27 subordinate, which is a separate Represents component. The actuator 27 is independent by the blade carrier 15 translationally linearly movable namely along a dash-dotted line Straight line L, which is also dash-dotted with represent central axis M an angle α forms.

The actuating part 27 is along the straight line L. in the exit direction of the blade carrier 15 in the direction a and movable in direction e of the blade carrier 15 in the direction e.

To guide the actuating part 27, this has two guide pins to be addressed as link pins 28 on the underside of the actuating part 27 for Project the bottom 29 of the lower housing shell 13. At the same time, the guide pins 28 protrude in the form of slot grooves to be addressed guide grooves 30, 31, which extend straight and into the bottom 29 of the bottom Housing shell 13 are embedded. The two Longitudinal axes LN of the two guide grooves 30, 31 are related the central axis M also at an angle α inclined.

The actuating part 27 has on one long side one the blade carrier 15 on its narrow side H comprehensive approach 32, shown in longitudinal section is. The approach 32 forms on its narrow side H of the blade carrier 15 facing the inside K a primary coupling element P, while the narrow side H of the blade support 15 is a secondary coupling element S has.

2-7 is in the approach 32 at a clamping point 33 a buckling bar 34 clamped on one side made of spring steel, the free end of which primary coupling part P forms.

The secondary coupling part S is according to the Fig. 2-7 from a recess on the narrow side H of the Blade carrier 15. The opening 36 of the recess has backwards in the direction of retreat z. So that the himself straight extending kink rod 34 in the unloaded Condition with its free end P in the undercut Can engage recess, the buckling bar 34th in the clamping point 33 a little towards the narrow side H of the blade carrier 15 arranged inclined.

At its rear end, the operating part has 27 an eyelet 37 into which the front end 35 a tension spring 38 is hooked. The back end 39 of the tension spring 38 is on a pin 40 of the lower Housing shell 13 of the knife housing 11 attached.

The knife 10 shown functions as follows:

The stored in the lower housing shell 13 and compared to the knife housing 11 only linearly translational movable blade carrier 15 is made using the Tension spring 24 held in its starting position A.

The actuating part 27 is described above Way by means of its guide pin 28 in the housing side rectilinear guide grooves 30, 31 in one Angle α led to the central axis M. The actuator 27 is by means of the in the longitudinal recess 21st of the extension 17 arranged tension spring 38 in held its rear starting position A.

The actuating part 27 has an actuating recess 41 of the upper housing shell 12 accessible Push handle handle 42, which the blade carrier 15 overlaps on the top and which with a Handle recess 43 is provided. The arrangement is like this met that on the neck 32 of the actuating part 27th the push handle handle 42 is fastened with one long side, is cohesively connected, such that the actuating part 27 a total Blade carrier 15 encompassing a C-shaped cross section having.

If the blade carrier carrying the knife blade 14 15 is to be placed in the cutting position an operating force F is exerted on the recessed grip 43. This actuating force F initially causes the actuating part 27 pushed a little towards a so that the front end (primary coupling element P) of the actuating part 27 in the recess (secondary coupling element S) of the blade carrier 15 engages, as can be seen from Fig. 3.

With further action of the actuating force F and Displacement of the actuator 27 in the direction a finally hit the two guide pins 28 of the Actuating part 27 on the front inner surfaces 44 of the two guide grooves 30, 31. The front inner surfaces 44 of the inclined guide grooves 30, 31 form accordingly stops for the movement limitation of the actuating part 27 in the direction of extension of the blade carrier 15, 4 shows in detail.

As a comparison between Fig. 3 and Fig. 4 shows the actuating member 27 compared to the Blade carrier 15 moves up, the buckling bar 34 bent to form potential spring energy, while the free end of the buckling bar 34 in the recess is held positively.

If now the knife blade 14 in the material to be cut 45 engages and the entire knife 10 a cutting movement 5 in the cutting direction C, tries a cutting reaction force in the blade carrier 15 positively received knife blade 14 in To hold cutting material 45. This has the consequence that the blade carrier 15 an additional relative movement can perform path x in the direction of extension x while the actuator 27 by means of its guide pin 28 on the stops 44 of the two inclined Guide grooves 30, 31 or another stop of the knife housing 11 is blocked.

Through this additional relative movement with the Path R in the extension direction x become the two coupling elements P and S disengaged, where the buckling rod 34 relaxes and stretches, so that the free end (primary coupling element P) on a path of movement to the side of the recess (secondary coupling element S).

If the cutting movement of the knife 10 in Cutting direction C is continued while the Knife blade 14 is in the material to be cut 45, the Push handle handle 42 are released, so that Actuating part 27 in its starting position (cf. starting position A can return according to FIG. 2), like Fig. 6 shows.

But as soon as the knife blade 14 the material to be cut 45 leaves, even if the knife blade 14 accidentally slides from the material to be cut 45, so that the Cutting reaction force is no longer present, pulls the tension spring 24 the blade carrier 15 with the knife blade 14 in the protected starting position A according to Fig. 2 back.

This retraction of the blade support 15 in the Starting position A also occurs when the blade holder 15 accidentally left in its forward position was like a comparison between the two 5 and 7 results easily.

The components 12, 13, 15, 27 and 42 form cast parts, So plastic injection or metal die-cast parts.

Fig. 8 shows an alternative embodiment, at which, in geometrical inversion, the buckling bar 34 intrinsically elastic plastic and the blade carrier 15 is integrally formed. The recess is from the approach 32 of the actuator 27th educated.

Claims (28)

1. Knife (10) having a knife housing (11), in which a blade carrier (15) holding a knife blade (14) is guided so as to be relatively movable, which blade carrier is displaceable by means of an actuating handle (42) counter to restoring force (tension spring 24) from a normal position (A), in which the knife blade (14) is retracted and protected in the knife housing (11), into a cutting position, in which the knife blade (14) projects from the knife housing (11), characterized in that the actuating handle (42) is formed by a separate actuating part (27), which is movable relative to the blade carrier (15) and is loaded counter to the movement of extension of the blade carrier (15) by a separate restoring force (38), that blade carrier (15) and actuating part (27) in their normal position (A) are motionally coupled by a primary coupling element (P) of the actuating part (27) or of the blade carrier (15) and by a corresponding second coupling element (S) of the blade carrier (15) or of the actuating part (27) for driving only in the direction of extension (x) of the blade carrier (15) but are mutually disengaged in the direction of retraction of the blade carrier (15), that the movement of the actuating part (27) in the direction of extension of the blade carrier (15) is limited, and that the blade carrier (15) is allowed an additional relative movement in extension direction (x), which moves the two coupling elements (P, S) out of engagement with one another.
2. Knife according to claim 1, characterized by a translatory rectilinear movement of the blade carrier (15).
3. Knife according to claim 1 or according to claim 2, characterized by a translatory rectilinear movement of the actuating part (27).
4. Knife according to claim 1 or according to claim 2, characterized by a translatory curved movement of the actuating part (27).
5. Knife according to one of claims 1 to 4, characterized in that the movement of the actuating part (27) in the direction of extension of the blade carrier (15) is limited by a stop (44).
6. Knife according to claim 5, characterized in that the stop (44) is formed by the knife housing (11).
7. Knife according to one of claims 1 to 6, characterized in that the joint movement of the actuating part (27) and the blade carrier (15) in the direction of extension of the latter (15) is a preliminary to a switching movement, by means of which the two coupling elements (P, S) are separable from one another.
8. Knife according to claim 7, characterized in that the two coupling elements (P, S) are separable from one another at right angles to their paths of motion.
9. Knife according to claim 7 or according to claim 8, characterized in that the preliminary to the switching movement is a different course of the paths of motion of the two coupling elements (P, S).
10. Knife according to claim 7 or according to claim 8, characterized in that the preliminary to the switching movement is a different course of the paths of motion of blade carrier (15) and actuating part (27) including their associated coupling elements (S, P).
11. Knife according to one of claims 7 to 10, characterized in that the preliminary to the switching movement is a link control (30, 31, 28).
12. Knife according to claim 11, characterized in that the link control (30, 31, 28) is associated with the actuating part (27) and the knife housing (11).
13. Knife according to claim 12, characterized by at least one link slot or by at least one guiding groove (30, 31) with, in each case; associated guide pins (28), wherein the longitudinal extension of the link slot or of the guiding groove (30, 31) in direction (a) of the actuating part (27) diverges relative to the direction of extension (x) of the blade carrier (15).
14. Knife according to claim 13, characterized in that the link slot or the guiding groove (30, 31) extends along a plane disposed at right angles to a main surface (47) of the knife blade (14).
15. Knife according to claim 13, characterized in that the link slot or the guiding groove (30, 31) extends along a plane disposed in or parallel to the main surface (47) of the knife blade (14).
16. Knife according to one of claims 12 to 15, characterized in that the link control (30, 31, 28) associated with the actuating part (27) comprises two link slots and/or guiding grooves (30, 31) with two corresponding guide pins (28) for producing the switching movement.
17. Knife according to one of claims 12 to 16, characterized in that the respective link slot or the respective guiding groove (30, 31) is formed by the knife housing (11), while the respective guide pin (28) is formed by the actuating part (27).
18. Knife according to one of claims 7 to 17, characterized in that the switching movement for separating the two coupling elements (P, S) from one another generates as a preliminary initially only a potential spring energy, which becomes effective only in the course of the additional relative movement of the blade carrier (15) in extension direction (x).
19. Knife according to one of claims 1 to 18, characterized in that one of the two coupling elements (S) is formed by a recess and the other of the two coupling elements (P) is formed by a projection of a load or pressure transmission element (34), which projection is latchable with the recess.
20. Knife according to claim 19, characterized in that the pressure transmission element forms a strut (34), which is clamped in at one end and the movable free end of which is the projection serving as primary (P) or secondary coupling element, which cooperates with a recess serving as secondary (S) and primary coupling element.
21. Knife according to claim 20, characterized in that the strut (34) is made of spring metal, in particular of spring steel.
22. Knife according to claim 20, characterized in that the strut (34) is formed cohesively on the blade carrier (15) or on the actuating part (27) and is made in particular of a plastics material having elastic properties.
23. Knife according to one of claims 19 to 22, characterized in that the recess is provided on the blade carrier (15) or on the actuating part (27).
24. Knife according to claim 23, characterized in that the recess is formed on the blade carrier (15) or on the actuating part (27).
25. Knife according to one of claims 1 to 24, characterized in that blade carrier (15) and actuating part (27) are disposed adjacent to one another in planes parallel to the main surfaces (47) of the knife blade (14).
26. Knife according to claim 24, characterized in that blade carrier (15) and actuating part (27) are disposed adjacent to one another in planes inclined relative to the main surfaces (47) of the knife blade (14).
27. Knife according to claim 25 or according to claim 26, characterized in that the actuating part (27) at one longitudinal side forms a projection (32), which overlaps the blade carrier (15) at its narrow side (H) and which at its inner side (K) directed towards the narrow side (H) of the blade carrier (15) forms the one (P) or the other (S) coupling element, while the narrow side (H) of the blade carrier (15) carries the other (S) or the one (P) coupling element.
28. Knife according to claim 27, characterized in that the sliding handle (42) is fastened, in particular cohesively joined, by one longitudinal side to the projection (32) in such a way that the actuating part (27) has a C-shaped cross section encompassing the blade carrier (15).

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