EP1946897B1 - Knife with automatically retractable blade - Google Patents

Abstract

The knife has a knife body with a pusher (6) driving a blade holder (2), and a trigger (4) acting on the holder. The pusher has a push stop (7) gripped with a counter stop (8) of the holder. The pusher and the holder comprise ramps cooperating for disengaging the push stop from the counter stop in a lateral direction perpendicular to a longitudinal retraction direction of a blade (1) when the holder and the blade are rotated towards an inclined cut position. The holder has a rear retention pin supported against a complementary shoulder of the body to retain the blade in the cut position.

Description

The present invention relates primarily to a knife with retractable blade automatically.

It relates secondly to a rotary trigger knife.

A retractable blade knife automatically is a safety knife for which the blade automatically enters the knife body when the cutting force disappears so that the operator can not hurt himself when the cut ends or is interrupted.

This type of knife is particularly suitable for cutting cartons, packaging or other materials such as protective plastic films.

A first example of a retractable blade knife is automatically given by the document DE 43 15 495 A1 which describes a knife whose blade, carried by a blade holder, leaves a body of the knife under the action of a pusher acting on the blade holder.

According to this document, a cam track device carried by the blade holder and pin carried by the knife body allow the blade to be positioned in a first waiting position, the pin being then positioned in a first housing of the path of cam, then, when a cutting force is applied, to position itself in a second position for which the pin is in abutment against a retaining stop of the blade in the advanced position, the blade retracting automatically when the cutting force disappears by the release of the pawn of the stop.

According to this first document, the second position of the blade is made by rotation of the blade and the blade holder in the plane of the blade.

In this device, the pusher comprises a first boss pushing on a second boss of the blade holder, the first boss protruding beyond the second towards the front of the knife during the engagement of the pin in the cam path to allow the positioning of cutting the blade and retracting the blade holder.

The device described in this first document is difficult to implement because it requires very precise tolerances for its operation and because there is a free zone between the housing of the cam path and the stop and that in the When the cutting force is low, the pin can escape the cam path because of the free zone which can lead to an inadvertent retraction of the blade when the cut is not completed or is just started.

A second example of a retractable blade knife is automatically described in the document DE 197 23 279 A1 wherein a blade device springing between a pusher and a blade holder is disengaged by further relative movement of the blade in the blade output direction.

The device for automatically retracting the blade when the cutting force vanishes from this second document is based on an additional longitudinal displacement of the blade forward in the direction of exit of the blade to disengage the blade spring between the push and the blade holder.

This device requires putting the push cart in abutment and requires a large cutting force to pull the blade out of the knife body a sufficient distance to clear the spring blade.

As according to the principle of this document it is necessary that the blade is pulled out of the knife by the cutting force, irregularities of the material to be cut can create sufficient variations in the cutting force to cause a premature return of the blade.

Finally, the document EP 1 177 865 A1 discloses a knife for which a device with detachable thrust notches between a pusher and a blade holder is released by a rotational movement of the blade.

This last device requires a large clearance of the blade both forward and in rotation to allow the notches to be released and again, a significant cutting force is required to ensure the release of the blade and its implementation. automatic removal position, a reduction of the cutting force which can also lead to premature retraction of the blade in the knife body.

The present invention aims at providing an automatically retractable blade knife for which the setting in cutting position of the blade and its pre-positioning in the release position is ensured even in the case of a low cutting force and for which a reduction cutting force does not lead to premature retraction of the blade.

A retractable blade knife automatically according to the preamble of claim 1 is known from the document EP 1 273 399 A1 .

For this purpose the present invention proposes a knife with retractable blade automatically according to the object of claim 1.

Advantageously, the knife body comprises an advanced abutment limiting the stroke of the blade holder in the output direction of the blade.

The present invention further relates to a rotary trigger control knife.

The knives provided with a trigger device comprise a knife holding body in which the blade is housed in the rest position and a trigger located under the body and acting in angular rotation with respect to the body about a transverse axis. with a knife.

The trigger is maneuvered with the fingers resting on the lower part of the knife body and a difficulty is to keep a reduced stroke of the trigger, to avoid a too wide movement of the fingers of the operator and too large opening of the hand which holds the knife, while the exit stroke of the blade may need to be important.

The trigger knives of the prior art permit rotational movement of the blade while it may be desirable to have an exit and retract movement of the longitudinal blade relative to the knife body.

The purpose of the trigger control device of the present invention is to allow a longitudinal output of the blade of a trigger knife over a large stroke while maintaining a reduced angular movement of the trigger.

To do this, the present invention provides a retractable blade knife having a blade mounted on a sliding blade holder in a knife body and a rotary trigger acting on the blade holder to release the blade from the knife body, for which the trigger acts on the blade holder through a device for transforming the rotary movement of the trigger into a longitudinal movement of the blade with respect to the knife body.

• en figure 1: une vue en éclaté perspective d'un couteau selon l'invention;
• en figure 2: une vue en perspective éclatée du mécanisme de sortie et de rétraction de la lame du couteau de la figure 1 ;
• aux figures 3A, 3B, 3C et 3D: des vues de côté du couteau de la figure 1 capot gauche enlevé, respectivement lame rentrée, la lame sortie, lame en position de coupe et lame rentrée en position de sécurité;
• aux figure 4A et 4B: des vues en perspective de l'avant du couteau de la figure 1 respectivement lame sortie et lame en position de coupe;
• aux figures 5A et 5B: des vues en coupe du porte lame et du poussoir du couteau de la figure 1 respectivement en position d'engagement et en position dégagée.

Other features and advantages of the present invention will become apparent on reading the following description of an exemplary embodiment of the non-limiting invention with reference to the figures which represent:

• in figure 1 an exploded perspective view of a knife according to the invention;
• in figure 2 : an exploded perspective view of the mechanism of exit and retraction of the blade of the knife of the figure 1 ;
• to the Figures 3A, 3B , 3C and 3D : side views of the knife from the figure 1 left cover removed, respectively blade retracted, the blade output, blade in the cutting position and blade retracted in the safety position;
• to the Figure 4A and 4B : perspective views of the front of the knife from the figure 1 respectively output blade and blade in cutting position;
• to the Figures 5A and 5B : cross-sectional views of the blade holder and knife pusher of the figure 1 respectively in the engagement position and in the released position.

The retractable blade knife automatically according to the invention is shown in exploded view in figure 1 to distinguish all the elements of the operating mechanism of the blade.

It comprises a knife body 3 provided with a housing for receiving a blade secured to a blade holder sliding in the housing.

The body of the knife comprises a right shell 3a, a left shell 3b and a removable front cover 13 to access the blade 1 and to change it.

The blade is manipulated, as will be seen later, by a rotary trigger 4 fixed in the body 3 by an axis 14 and rotatable about this axis.

The blade 1 is mounted on a blade holder 2 sliding longitudinally in the body 3 constituted by the shells 3a, 3b of the knife.

The trigger 4, rotatably mounted on the body, acts on the blade holder 2 to release the blade 1 from the knife body through a rod 5 and a pusher element 6 for driving the blade holder in a longitudinal direction of exit of the blade.

When the trigger is depressed, the rod 5 pushes the pusher which in turn drives the blade holder 2 to the output position of the blade 1.

To do this, the pusher element 6 comprises a thrust abutment 7, engaged in an outlet direction of the blade, with a counter-abutment 8 of the blade holder 2.

The rod and the pusher thus constitute a device for transforming the rotary movement of the trigger in a longitudinal movement of the blade relative to the body of the knife.

The blade holder 2 is returned to the retracted position of the blade by a first spring element 9 of spiral spring type, a first end of which is fixed to the blade holder and a second end of which is fixed to a lug 15 of the right hull 3a of the knife.

As will be explained more fully later, in the output position of the blade, the blade holder is free to pivot in the body and in the plane of the blade so that a rotation of the blade holder in the body releases the stop 7 against the abutment 8 and releases the blade holder 2 of the pusher 6, the blade holder 2 then being free to return to the retracted position of the blade under the action of the first spring element 9 and on disappearance of the cutting force.

The figure 2 represents the elements of the exploded mechanism and in particular shows the rod 5 which has a first and a second end 5a, 5b.

The first end 5a of the rod 5 is rotatably mounted on the pusher element 6 and comprises for this purpose, according to the example shown, a housing 16 receiving an axis 17 of the pusher 6.

The second end 5b of the link constitutes an axis received in a slot extending from a trigger extension so that the second end 5b of the link is rotatably mounted in the slot 10 of the trigger 4.

The light 10 is an oblong slot so that the second end 5b of the link 5 is further slidably received in the slot 10.

Thus, when the trigger is operated, the link 5 transforms the rotational movement of the trigger into a translational movement of the pushing push but, on the other hand, as will be seen later, the end 5b of the link is able to advance in the light 10 to increase the longitudinal displacement of the pusher and provide a reduction in the movement of the pusher.

To obtain this movement of the rod in the forward light, that is to say towards the part of the knife from which the blade leaves, and to obtain this reduction, the second end 5b of the link is rotatably connected to a first end 11a of a thrust arm 11.

The counter-thrust arm has a second end 11b rotatably mounted on the body 3a of the knife. The second end 11b has for this purpose a housing receiving an axis 18 protruding from the shell 3a towards the inside of the knife and represented in particular in figure 1 .

The link 5 and the arm 11 form two branches of an articulated leg and form adjacent sides of a deformable triangle. The junction point of the rod 5 and the arm 11 provides a hinge located at the top of the deformable triangle.

Advantageously and to guide the rod, the hinge is positioned in the oblong slot of the trigger.

To achieve the articulation, the arm 11 has a tubular axis 20 of diameter slightly less than the width of the light and the link has a cylindrical axis 21 inserted into the hole of the tubular axis 20.

The light receives the articulation at the junction point of the rod and the arm, the rod and the arm forming the two adjacent sides of the deformable triangle, so that pressing the trigger causes the deployment and extension of the leg caused by the sliding of the joint of the leg in the light.

The arm and the rod are arranged on either side of the trigger to balance the forces applied to the deformable triangle by the movement of the trigger.

The oblong light is made in a canvas of an extension of the trigger.

The second end 11b of the counter-thrust arm provides a fixed fulcrum on the body 3a.

A further advantage of the present invention is to allow to create a hard point at the beginning of the extraction movement of the blade to prevent inadvertent release of the blade on a low pressure on the trigger.

The leg constituted by the rod and the arm is comparable to a compass whose first free end achieves a fixed point, the extension of the compass when pressing on its top pushes the pusher 6, arranged at the second free end of the compass , to take out the blade.

The longitudinal displacement of the blade holder results from the extension of the jamb.

Because the articulation of the leg can slide in the light, we obtain a reduction in the distance traveled by the blade holder relative to the distance traveled by the trigger.

The rotational movement of the trigger is transformed into longitudinal movement of the blade holder by movement of the joint in the lumen and extension of the leg.

According to this particular embodiment of the invention, the forces applied to the trigger and its stroke remain moderate relative to the output stroke of the blade and a hard point can be obtained at the beginning of movement according to the angle that the gives between the link and the arm and according to the inclination of the light.

The Figures 3A, 3B and 3C represent the different operating phases of the knife from the rest position to the cutting position and finally 3D figure , seen from the front of the knife, the safety position at the end of cutting for which the trigger is still pressed but the blade has already returned.

The figure 3A represents in particular the rest position of the blade knife retracted before pressing the trigger.

The figure 3B represents the blade in the exit position and the leg being extended.

The figure 3C represents the blade in cutting position and the 3D figure represents the blade retracted into the safety position while the trigger 4 is still actuated and the pusher 6 is still in the advanced position.

These figures more particularly illustrate the operation of the thrust device of the blade and the device for holding the blade in the cutting position.

In these figures is represented in particular the positioning of the pusher element 6 with respect to the blade holder 2.

To push the blade holder and lift the knife blade, the pusher has a thrust stopper 7, engaged in a longitudinal direction of output of the blade with a counter-abutment 8 of the blade holder 2.

Thus, in the exit direction of the blade as shown in Figures 3A and 3B , the thrust stop is engaged with the rear face of the abutment and when the trigger 4 is pressed, the pusher 6 pushes the blade holder 2 forward which causes the blade to come out.

When a cutting operation is performed, the blade holder pivots in the plane of the blade in the position of the 3D figure in response to the cutting force.

To hold the blade in this inclined cutting position, the blade holder 2 comprises a rear retaining pin 31 coming to bear against a shoulder 32 complementary to the body.

During the rotation of the blade holder, according to the principle of the present invention The thrust of the pusher abutment and the abutment of the blade holder are disengaged so as to arm the knife safety device allowing rapid retraction of the blade into the blade. body of the knife when the cutting force is canceled.

To allow the disengagement of the thrust stop and against the stop, the pusher and the blade holder comprise ramps 22, 23 cooperating to release the thrust abutment 7 of the abutment 8 in a lateral direction perpendicular to said longitudinal direction under the action of the rotation of the blade holder and the blade to the inclined cutting position.

The operation of the ramps is represented in particular Figures 4A and 4B and to Figures 5A and 5B sectional views of the blade holder and the pusher.

In Figure 4A seen from the front of the knife in perspective without the left cover, the blade is shown in the advanced position, the thrust stopper 7 being engaged behind the abutment 8. At the Figure 4B seen from the front of the knife in perspective without the left cover, the blade is shown in the cutting position with the lug 31 received in the housing 32 to retain the blade holder.

Under the action of the ramp 23 of the blade holder 2 on the ramp 22 of the pusher, the pusher pivots laterally so that the stop 7 deviates laterally from the abutment 8.

The abutment 8 then passes under the abutment 7 by simply rotating the blade holder during pivoting and / or by a slight recoil of the blade and the blade holder.

To move from the advanced exit position to the cutting position, the rotation of the blade between the advanced position and the inclined cutting position is around an axis perpendicular to the plane of the blade.

Unlike the device described in the document DE 197 23 279 A1 , the disengagement between the pusher and the blade holder does not result from an additional movement towards the front of the blade holder but results from a rotation of the blade holder upwards and backwards, which is particularly advantageous because there is no need for a tensile cutting force to arm the safety device ensuring the retraction of the blade when the cutting force is canceled.

Moreover, as we see in Figure 4A , the knife body comprises an advanced stop 33 limiting the stroke of the blade holder 2 in the output direction of the blade.

Conversely, the stroke of the pusher 6 is not limited forward which promotes the action of the ramps 22, 23 and the passage of the thrust abutment 7 beyond the top of the abutment 8 as shown in FIG. Figure 4B .

The relative positions of the blade holder and the pusher Figures 4A and 4B are represented at Figures 5A and 5B respectively which are sectional views in a vertical plane perpendicular to the major axis of the knife and passing approximately through the middle of the tab constituting the thrust abutment 7.

The Figure 5A represents the blade holder and the pusher during the thrust with the relative position of the abutment 8 with respect to the thrust abutment dotted, the thrust stop being parallel to the body bearing the abutment, the Figure 5B represents, in an exaggerated position for the illustration, the pusher inclined by the support of the ramp 23 on the ramp 22 until the thrust stop can escape from the abutment 8.

Thus, a rotation of the blade holder upwardly leads to a rotation of the pusher to the right to disengage the abutment from the abutment while the blade holder remains in an inclined cutting position due to the retention of the stub 31 in the dwelling 32.

As previously seen, the blade holder 2 is connected to the body by a first spring element 9.

The first spring element 9 is positioned to be adapted to return the blade holder in retracted position of the blade from the inclined cutting position in the absence of cutting force.

The retracted position of the blade holder is shown at 3D figure .

The retraction of the blade is done when the operator releases its support on the object to cut or when the blade out of the object to be cut which allows the blade to rebase into the exit position and then enter the body since the thrust stop is no longer in engagement with the counter-stop.

The pusher 6 is for its part recalled to a retracted position by a second spring element 12 which further allows to bring the trigger in the remote position when the operator releases the latter.

This second spiral spring type spring element has a first end which is hooked on the pusher and a second end which hooks on a lug 19 in the body of the knife.

When the trigger is released, it is desirable that the blade retracts into the body and the pusher 6 is recalled to a position retracted by the second spring element 12.

This spring also makes it possible to place the pusher in the rear stop position in which the abutment 7 of the pusher is positioned behind the abutment 8 of the blade holder to re-position the pusher in the drive position of the blade holder during a bearing. later on the trigger.

As seen above, the operation of the stop device and the disengagement system between the pusher and the blade holder are based on the realization of a first longitudinal ramp 22, above the abutment 7 of the pusher, on which rests a shoulder forming a second ramp 23 in the upper part of a support against the abutment 8.

When the blade holder is raised, the stop is pushed laterally by the thrust of the ramp 23 of the shoulder on the ramp 22 and is thus released from the abutment 8. As soon as the cutting force is released, the blade holder recalled by its spring element 9 back in the body of the knife even if the trigger is maintained pressed.

When the trigger is released, the pusher moves back and the thrust stopper 7 returns to the top of the abutment 8 thanks to the presence of two ramps 24 and 25 arranged facing respectively on the blade holder and on the pusher and represented in FIG. 3D figure .

To avoid any risk of separating the pusher from the blade holder when the blade holder is pulled in the blade outlet position, the blade holder comprises a pin 26 holding the pusher in a direction directed towards the rear of the blade holder so that pulling on the blade holder drives the pusher.

The longitudinal guide of the blade holder in the knife is formed by a lower bearing surface 30 on which slides a lower rim 29 of the blade holder as shown in FIG. figure 1 and the longitudinal guide of the pusher is formed by a device comprising grooves 27 in the upper part of the blade holder, these grooves receiving rails 28 made in the wall of the shells 3a, 3b of the body 3 of the knife.

The invention is not limited to the example shown and in particular the safety device for retracting the blade at the end of cutting is adaptable to a knife for which a maneuvering button actuates directly the pusher or is integrated in the pusher as in the document DE 43 15 495 A1 .

In addition, the realization of the rotary joints between the rod and the pusher and between the arm and the body of the knife can be reversed so that the rod and the arm have an axis while the pusher and the body comprise receiving housing of these axes while remaining within the scope of the present invention.

Similarly, the trigger and linkage operating system can be adapted to a knife without retractable blade automatically.

Claims (11)

1. A knife with an automatically retractable blade, comprising a knife body provided with a housing receiving a blade secured to a blade holder and provided with a pusher for driving the blade holder in a longitudinal direction of deployment of the blade, for which the pusher element (6) comprises a thrust stop (7), in engagement, in a longitudinal direction of deployment of the blade, with a counter-stop (8) for the blade holder (2), the pusher and the blade holder comprising ramps (22, 23) cooperating so as to free the thrust stop (7) from the counter-stop (8), characterised in that the freeing of the stops is achieved by pivoting of the pusher element in a lateral direction perpendicular to said longitudinal direction under the action of a rotation of the blade holder and blade upwards and rearwards towards an inclined cutting position, the blade holder (2) for its part comprising a rear holding lug (31) coming to bear against a complementary shoulder (32) on the body in order to hold the blade in the inclined cutting position.
2. A knife according to claim 1, wherein the knife body comprises an advanced stop (33) limiting the travel of the blade holder (2) in the direction of deployment of the blade.
3. A knife with retractable blade according to claim 1 or 2, wherein the blade holder (2) is connected to the body by a first spring element (9) and wherein the first spring element (9) is positioned so as to be arranged to return the blade holder into the retraction position of the blade from the inclined cutting position in the absence of any cutting force.
4. A knife with retractable blade according to one of the preceding claims, wherein the pusher (6) is returned towards a retracted position by a second spring element (12).
5. A knife according to one of the preceding claims, wherein the rotation of the blade between an advanced position and the inclined cutting position takes place around an axis perpendicular to the plane of the blade.
6. A knife with retractable blade according to one of the preceding claims, comprising a blade (1) mounted on a blade holder (2) sliding in a body (3a, 3b) of the knife, and a rotary trigger (4) acting on the blade holder (2) in order to bring the blade (1) out of the knife body, wherein the trigger acts on the blade holder through a device (5, 6) converting the rotary movement of the trigger into a longitudinal movement of the blade with respect to the body of the knife, the trigger (4) being mounted so as to rotate on the body, the conversion device comprising a link (5) and a pusher element (6) driving the blade holder (2) in the deployed position of the blade (1) in a longitudinal direction with respect to the body of the knife.
7. A knife with retractable blade according to claim 6, wherein the link (5) comprises first and second ends (5a, 5b), the first end (5a) of the link (5) being mounted so as to rotate on the pusher element (6), the second end (5b) of the link being mounted so as to rotate in an aperture (10) in an extension of the trigger (4).
8. A knife with retractable blade according to claim 7, wherein the aperture (10) is an oblong aperture, the second end (5b) of the link (5) being slideably received in the aperture (10).
9. A knife with retractable blade according to claim 7 or 8, wherein the second end (5b) of the link is connected rotatably to a first end (11a) of a counter-thrust arm (11) also comprising a second end (11b) mounted for rotation on the body (3a) of the knife.
10. A knife with retractable blade according to claim 9, wherein the link (5) and the arm (11) form two branches of an articulated pair of legs and form adjacent sides of a deformable triangle, the junction point of the link (5) and arm (11) producing an articulation situated at the vertex of the deformable triangle, this articulation being positioned in the aperture in the trigger.
11. A knife with retractable blade according to claim 9 or 10, wherein the second end (11b) of the counter-thrust arm produces a fixed abutment point on the body (3a).

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