WO2014125004A1

WO2014125004A1 - Blade holder device having a mechanism for automatic blade retraction at the end of cutting and safety knife comprising same

Info

Publication number: WO2014125004A1
Application number: PCT/EP2014/052785
Authority: WO
Inventors: Jean-Claude Peyrot
Original assignee: Mure Et Peyrot
Priority date: 2013-02-14
Filing date: 2014-02-13
Publication date: 2014-08-21
Also published as: EP2956278A1; FR3001908A1; EP2956278B1; FR3001908B1

Abstract

The subject of the invention is a safety knife provided with a mechanism for automatic retraction of the blade at the end of cutting, having a body (50), a carriage (10) and a blade holder (20), the blade holder (20) being able to slide with respect to the carriage between a withdrawn retracted position of the blade and an advanced extended position of the blade, the knife being provided with a system of journals/slideways (11, 21, 11', 21') for guiding the blade holder between the advanced position and the withdrawn position, the journals (21, 21') forming, in the advanced position, a blade holder rotation axis that is designed to incline the blade holder with respect to the direction of extension of the blade in response to a cutting force at an inclined cutting position (α) and for which the mechanism has a push rod (30) for retaining the blade holder that is disposed between the carriage and the blade holder and is designed to disconnect the blade holder from the carriage during the inclination of the carriage towards the inclined cutting position.

Description

BLADE HOLDER DEVICE WITH AUTOMATIC BLADE RETENTION MECHANISM AT THE END OF CUTTING AND SAFETY KNIFE

UNDERSTANDING

Background of the invention

Field of the invention

The present invention relates to a blade holder device with automatic blade retraction mechanism at the end of cutting and a safety knife comprising it.

As part of the protection of operators operating knives comprising a blade protruding longitudinally from a knife body for cutting objects such as packaging, cartons, plastic films, it is known to arrange the blade on a door blade driven in displacement by an operating device such as a pusher and to provide means for disengaging the pusher and the blade holder at the end of cutting and in particular an automatic blade retraction mechanism when the blade escapes from an object to cut.

Technological background

There are many embodiments of knives with a blade that can take a safety position in the knife body and a cutting position out of the knife body and having an automatic blade retraction mechanism at the end of cutting and when the blade escapes from an object to cut.

An example of a safety knife comprising a blade device with an automatic blade retraction mechanism is described in document EP 1 985 417 A1. This document describes a knife comprising a blade holder and a carriage provided with a pushing button of the sliding blade door longitudinally in the body of the knife to bring out the blade carried by the blade holder of the knife body.

In this knife, the blade holder and the carriage are connected by a first spring member applying a first drive stop of the carriage against a second drive stop of the blade holder, said first and second stops being adapted to disengage by rotation of the blade. blade door relative to the carriage under a cutting force (E).

Brief description of the invention

The present invention aims to provide a blade holder device having a compact blade retraction mechanism and adapted to provide a good guarantee of retraction of the blade holder at the end of cutting.

In addition, the device of the present invention is designed so as to allow secure operation guaranteeing the return of the blade at the end of cutting even if the blade is not completely out of the knife, especially in the case where the operator performs a cut without pushing the pusher completely.

To this end, the present invention proposes a safety knife provided with an automatic return mechanism of the blade at the end of cutting, comprising a body, a carriage and a blade holder, the blade holder being able to slide relative to the body and to the carriage between a retracted position of retraction of the blade and an advanced output position of the blade, characterized in that it is provided with a system of journals / guide rails of the blade holder between the advanced position and the retracted position, the journals further forming an axis of rotation of the blade holder adapted to incline the blade holder in a cutting position inclined with respect to the blade exit direction in response to a cutting force and for which the mechanism comprises a push rod of blade holder disposed between the carriage and the blade holder and adapted, in a first position, to urge the blade holder forward and, in a second position, to disengage the blade holder from the blade trolley when tilting the blade holder to the inclined cutting position.

According to an advantageous embodiment, the push rod is provided with a first pin and movable in rotation relative to the blade holder so that the first pin is engaged with a stop on the carriage, blade holder in position. advanced for the rod to push the blade gate, and the first toe out engaging with said stopper to disengage the blade holder from the carriage, blade holder in an inclined cutting position, so that the blade holder can pass, at the end of cutting, from the cutting position inclined to the retracted position under the action of a first return spring.

Advantageously, the push rod is mounted to rocker and comprises a front arm and a rear arm extending from two opposite sides of a rotary axis on the blade holder.

According to an advantageous embodiment, the ratio of the length of the rear arm to the length of the front arm defines an amplification of the rotational displacement of one end of the rear arm in response to a rotational displacement of one end of the front arm during a Tilt the blade holder under a cutting force. Thus, the angle of inclination of the blade holder can remain limited while the first pin clear of its abutment.

Advantageously, a distal end of the rear arm of the push rod carries the first pin and a distal end of the front arm carries a second pin, said second pin being received in a groove of the carriage.

The second pin, retained by the sides of the groove of the carriage, and the rotary shaft, retained on the blade holder, are advantageously configured to cause, when the blade door is tilted relative to the carriage, a rotation of the rear arm the push rod relative to the carriage, which rotation disengages the first pin from the stop.

According to particular embodiments, the stopper comprises a tongue or a shoulder prohibiting the return of the first pin in engagement with the stopper.

Advantageously, the first pin, once disengaged from the stop, is found in a cam track or a gutter extending to a rear portion of the carriage corresponding to a retracted position of the blade gate defining the retracted position of the blade.

The cam path preferably comprises a profile adapted to return the first pin in alignment with the stopper, blade holder in the retracted position.

According to an advantageous embodiment, the carriage comprises a maneuvering pusher protruding from the body through an opening of the body. The carriage is advantageously connected to the body through a second return spring of the carriage in a rear rest position.

According to a particular embodiment, the blade holder is connected to the body through the first return spring.

The carriage being positioned in a rear position of rest, the body preferably comprises a positioning stop of the blade holder relative to the carriage so as to engage the first pin with the stopper.

The carriage advantageously comprises a temporary stop adapted to hold the blade holder in the advanced position in the presence of a cutting force.

The gutter is preferably constituted by a window of the carriage in which is positioned a spring arm carrying the stopper.

According to a first variant, the rails for receiving the journals are made by windows in the carriage, according to a second variant the rails for receiving the journals are made by grooves in the body of the knife.

Brief description of the drawings

Other features and advantages of the invention will become apparent on reading the following description of a nonlimiting exemplary embodiment of the invention with reference to the drawings which represent:

in Figure 1: an exploded perspective view of a knife made according to the invention;

in Figures 2A to 2D: schematic side views of the knife of Figure 1 according to different phases of operation;

in FIG. 3: a view showing a side view of a blade holder and a carriage according to the principle of the invention;

in FIGS. 4A and 4B: side views of the blade and carriage holders of FIG. 4 according to two operating positions;

in FIGS. 5A and 5B: exploded views of an alternative embodiment of the invention;

in FIG. 6: a perspective sectional detail of the carriage of the variant of FIG. 5A;

in Figure 7: a perspective view of the carriage of the variant of Figure 5A. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION An example of a safety knife made according to the invention is described in exploded at the fiqurel.

It comprises a knife body 50, a carriage 10 and a blade holder 20. The blade holder is inserted into the carriage which is adapted to slide in the body 50.

The blade holder receives a blade 1 which extends to the front of the blade holder.

The blade holder 20 can slide longitudinally with respect to the carriage 10 between a retracted retraction position of the blade and an advanced output position of the blade.

There is thus a double sliding, that of the carriage approaching the blade holder of an opening 53, blade outlet of the knife body 50, and that of the blade holder in the carriage which, in the advanced position, realizes the effective exit of the blade and, in retracted positon, the blade enters the knife whatever the position of the carriage.

To remove the blade from the knife, the carriage has an operating button or pushbutton 16 protruding from the body through an opening 51 of the body.

This pusher, actuated by the operator, moves the carriage forward of the knife body where the opening 53 of the output blade.

The blade holder is biased back by a first spring 40, the carriage being returned to a rear rest position by a second spring 60.

The first and second springs are fixed on retaining means disposed on the body of the knife.

The blade holder comprises pins 21 formed by cylindrical pins aligned along a common axis perpendicular to the sliding movement of the blade holder and arranged in the lower rear portion of the blade holder, these pins being defined as cylindrical parts around which the blade holder is capable to have a rotational movement.

These pins move in slides 1 1 made on the carriage in the example of Figures 1 to 4B.

A rocking push rod 30 whose function will be seen further is articulated on the blade holder by means of a rotary shaft 22 and a housing 35, the axis being here on the blade holder and the housing on the push rod, this configuration can however be reversed in the context of the invention.

The push rod 30 includes a front arm 33 and a rear arm 32 extending from two opposite sides of the housing 35 for the rotary shaft 22 on the blade holder.

A distal end of the rear arm 32 of the push rod 30 carries a first pin 31 and a distal end of the front arm 33 carries a second pin 34, said second pin being received in a groove 13 of the carriage.

FIGS. 2A to 2D show steps in the operation of a knife according to the invention and in particular make it possible to visualize the sliding of the blade holder 20 in the carriage between an advanced output position of the blade and a retracted retracted position of the blade. blade.

The sliding between the output position of the blade and the retracted position is achieved by means of an automatic retraction mechanism of the blade at the end of cutting.

In FIG. 2A, the blade is released by pushing on the pusher 16 of the carriage 10 which drives the blade holder by the engagement of the first pin 31 with the stopper 12. With the blade holder in the advanced position, the first pin 31 is engaged with the stopper 12 of the carriage.

In FIG. 2B, under the action of a cutting force E, the blade holder pivots at an angle α about an axis constituted by the journals 21 abutting in the slides 1 1.

This pivoting disengages the first pin 31 from the stopper 12, the pin 31 then being in engagement with a temporary stopper 101 so that the blade remains in engagement with the object to be cut.

Once the cutting force is canceled, the pin disengages from the temporary stop and the blade holder retreats under the action of the return spring 40 which makes the blade enter the body of the knife even if the carriage is still pushed by the operator pressing the pusher 16. This retracted position of the advanced carriage blade corresponds to Figure 2C.

Finally, when the operator releases the carriage 10, the latter returns to the retracted position according to FIG. 2D and the blade holder returns to the position of departure for which the first pin 31 is in engagement with the stopper 12.

The mechanism is therefore mainly achieved by means of the rocker push rod and a stop stop 12 retaining the blade holder in the advanced position, engaged in said advanced position with the first pin 31 of the push rod 30 .

The stopper is made by means of a flexible tongue 12a in the embodiment of Figures 1 to 4B.

According to the embodiment of Figure 1, the blade holder and the carriage comprise a trunnion / guide system 1 1, 21 for guiding the blade holder between the advanced position and the retracted position during sliding of the blade holder.

Two journals, one on the left and one on the right of the blade holder slide in two slides 1 1 on each side of the carriage 10.

The journals 21 further form an axis of rotation of the blade holder that the blade holder is fully advanced or in a forward intermediate position.

Therefore, the blade holder is adapted to tilt backward in response to a cutting force by rotation about the axis constituted by the pins in the slides 1 1 to take a cutting position inclined at an angle shown in Figure 2B.

During the inclination of the blade holder 20, 20 ', the push rod 30 has a tilting movement about its axis of rotation 22 on the blade holder as shown in Figure 3 where the blade holder and the carriage are shown separately.

The starting position of the push rod is represented in dashed line according to the angle β and initially the first pin is at the marked position 31 a.

The tilting movement of the push rod is caused by the rotation of the front of the blade holder with respect to the carriage which induces a rotation of the arm carrying the second pin 34 retained in the groove 13 of the carriage with respect to the axis 22 .

In this lever movement, the first pin 31 moves itself in rotation about the axis 22 according to the angle β in a movement amplified by the lever arm effect of the push rod. The arrival position of the first pawn is marked 31 b.

As a result, the first pin 31 disengages from the stopper 12. The ratio of the length of the rear arm 32 to the length of the front arm 33 defines the amplification of the rotational displacement of the end of the rear arm in response to the rotational displacement of the end of the front arm during the inclination of the blade holder under a cutting effort.

This amplification allows as shown at the top of Figure 3 free clearance of the pin 31 relative to the stop 12 while maintaining a reduced angle and therefore a small displacement of the second pin.

The mechanism of automatic re-entry of the blade holder at the end of cutting is based on the use of the push rod 30 placed between the carriage and the blade holder and designed to separate the assembly during the inclination of the blade holder in the position of inclined cut. This separation is effected according to the example by the engagement output of the first pin with the stop, blade holder in inclined cutting position, so that the blade holder can move back under the action of the first return spring 40 arranged between the blade holder and the knife body at the end of cutting when the force on the blade is released.

According to the example of FIG. 1, the stopper is associated with a tongue 14 preventing the return of the first pin 31 in engagement with the stopper 12.

FIGS. 4A and 4B of the embodiment of FIG. 1 represent an enlarged view of the operation of the device in the return phase of the blade holder in the retracted rear position. In FIG. 4A the first pin 31 is disengaged from the stopper, the blade holder being in an inclined position according to the angle a under the action of the cutting force and the springs 40, between the blade holder and the body. knife and 60, between the carriage and the body of the knife, are stretched.

When the cutting force is canceled, the blade holder, the first pin 31 is no longer retained, moves back to take the rear position of Figure 4B where the pin 31 is at the end of the rear stroke in the carriage 10 and where the spring 40 is relaxed.

In its recoil movement, the pin 31 is guided in a cam path 15 extending to a rear portion of the carriage corresponding to a retracted position of the blade holder defining the retracted position of the blade.

The cam path 15 has a profile adapted to return the first pin 31 in alignment in a longitudinal axis A of the knife with the stopper 12, blade holder 20 in the retracted position. The temporary stop 101 shown in Figure 2A keeps the blade advanced as the blade is in the cutting position even if the cutting force is low, the pin being in back support against the temporary stop as shown in Figure 2B.

On the other hand, as soon as the blade has emerged from the material to be cut, the blade holder can return to the non-inclined position under the action of the pull of the spring 40.

This spring is in particular arranged relative to the axis constituted by the pins 21, 21 'so as to return the blade holder from the inclined position to a position in alignment with the carriage. This causes the first peg to come out of the temporary stop and move the blade holder back into the retracted position of the blade.

To maneuver the knife, the pusher 16 protrudes from the body through an opening 51 of the body. This pusher, integral with the carriage 10, 10 ', allows to push in the advanced position. The second return spring 60 of the carriage in a rear rest position acts against the thrust on the pusher 16.

As seen previously, the blade holder 20 is connected to the body 50 through the first return spring 40.

When the carriage 10 is positioned in a rear rest position under the action of the second return spring 60, the body comprises a stop 52 which stops the blade holder in its recoil under the action of the first spring 40 and allows the setting of the blade holder in advanced position relative to the carriage and the engagement of the first pin with the stopper 12 as shown in FIG. 2D.

In other words, the carriage moves back with respect to the blade holder by a distance sufficient for the pin to come into engagement with the stopper.

The example shown in FIGS. 5A to 7 corresponds to a variant of the invention which makes it possible in particular to reduce the width and the height of the knife.

Indeed, in the first place, in this variant, the carriage does not surround the blade holder laterally but straddles the blade holder which reduces the width of the knife.

In addition, the trunnions of the blade holder are received in slides 1 1 'of the knife body instead of sliders of the carriage which reduces the height of the carriage and therefore the knife. A difference with respect to the previous embodiment is that the stopper 12 'is carried by a flexible arm 12b in the embodiment of FIGS. 5A to 7

According to this embodiment, the flexible arm 12b bearing the abutment 12 'equivalent to the abutment 12 is shown in perspective section in Figure 6. The abutment 12' is constituted by a shoulder at the end of the arm, a cover 12c covering the abutment remaining resting on the first pin 31 to maintain the arm in constraint as the first pin bears against the stopper.

According to Figure 5A, the slides 1 1 'are further made not by lights on the carriage but by grooves in two half-shells forming the knife body receive the pair of pins 21' of the blade holder.

The pins in this case slide in the pair of slides on the knife body.

This is simpler to achieve for a knife whose body 50 'is curved but does not change the principle of the invention since the blade holder 20' tilts rearwardly relative to the carriage 10 'in the same way as in the previous embodiment in the cutting position during the rotation of the blade holder about the axis constituted by the pins 21 retained in the slides 1 1 'at the end of the slides or before the end of the slides.

In the embodiment of Figure 6, the arm 12b comprises a shoulder prohibiting the return of the first pin 31 in engagement with the stopper 12 'formed by a side face 12d of the arm 12b. This shoulder has the same use as the tongue 14 of the previous embodiment while being easier to manufacture.

In this last embodiment, when the pin moves and leaves its engagement with the stop 12 ', it disengages the cover 12c which eliminates the bending stress of the arm and allows it to return to a rest position in which the pin 31 abuts laterally against the lateral face 12d of the arm and can not come into engagement with the face 12 'stop stop.

In this position, the pin no longer holds the blade holder forward and the latter moves back under the action of the return spring 40 as soon as the first pin leaves its engagement with the temporary stop 101 'made in the carriage 10'. Once past the temporary stop 101 'adapted to retain the blade holder in the advanced position as the cutting force is present, the pin is found here free to retreat into a groove formed by the window 102 of the carriage 10' in which is positioned the arm 12b carrying the stopper 12 as shown in Figure 7.

Once the blade holder in the retracted position, that is to say when the pins 21 'are found in the rear part of the slides 1 1', a stop 52 'ensures that the blade holder 20' is positioned parallel to the carriage so that the rod thrust is found in alignment with the abutment 1 1.

An important aspect of the invention is that the push rod is a toggle piece between the carriage and the blade holder and that its angular tilting is controlled by the rotational movement of the blade holder relative to the carriage. This is a continuously constrained movement for which the push rod takes positions defined by the rotation of the rod under the action of the rotation of the blade holder unlike for example a device where a spring between the blade holder and the carriage is stressed and released by an additional relative movement towards the front of the blade holder relative to the carriage.

In addition, when the blade holder is connected to the carriage by means of the push rod, the blade holder is secured to the carriage so that the blade holder can not advance relative to the carriage.

The invention is not limited to the examples shown and encompasses variants of thrust rod devices between a carriage and a blade holder falling within the scope of the claims and in particular it is possible to use embodiments of the first embodiment of the invention. realization described with the second and vice versa. For example, it is possible to use the feature that the trunnion receiving rails are on the body with a stop and stop device of the type of the first embodiment.

Claims

R E V E N D I C A T IO N S

1 - Safety knife provided with a mechanism for automatic re-entry of the blade at the end of cutting, comprising a body (50), a carriage (10) and a blade holder (20), the blade holder (20) being slidable by relative to the body and the carriage between a retracted position of retraction of the blade and an advanced output position of the blade, characterized in that it is provided with a trunnion / slide system (1 1, 21, 1 1 ', 21 ') for guiding the blade holder between the advanced position and the retracted position, the journals (21, 21') further forming an axis of rotation of the blade holder adapted to incline the blade holder in an inclined cutting position (a) relative to the direction of exit of the blade in response to a cutting force and for which the mechanism comprises a push rod (30) of the blade holder disposed between the carriage and the blade holder and adapted, in a first position, to push the blade holder forwards and, in a second position, to disengage the carriage slide holder when tilting the blade holder to the sloped cut position.

2 - Safety knife according to claim 1 wherein the push rod (30) is provided with a first pin (31) and rotatable relative to the blade holder so that the first pin is engaged with a stop 'stop (12, 12') of the carriage, blade holder in the advanced position, and the first pin (31) is out of engagement with said stopper, blade holder in inclined cutting position, so that the blade holder can passing, at the end of cutting, the cutting position inclined to the retracted position under the action of a first return spring (40).

3 - Safety knife according to claim 2 wherein the blade holder (20) is connected to the body (50) through the first return spring (40).

4 - Safety knife according to claim 1, 2 or 3 for which the push rod (30) is mounted to rocker and comprises a front arm (33) and a rear arm (32) extending from two opposite sides of a rotary shaft (22) of the push rod on the blade holder.

5 - Safety knife according to claims 2 and 4 wherein a distal end of the rear arm (32) of the push rod (30) carries the first pin (31) and a distal end of the front arm (33) carries a second pin (34), said second pin being received in a groove (13) of the carriage. 6 - Safety knife according to claim 5 wherein the ratio of the length of the rear arm (32) to the length of the front arm (33) defining an amplification of the rotational displacement of an end of the rear arm in response to a rotational movement of one end of the front arm when tilting the blade holder under a cutting force.

7 - Safety knife according to claim 5 or 6 for which the second pin (34), retained by the sides of the groove (13) of the carriage, and the rotary shaft (22, 35), retained on the blade holder, are configured to cause, during a tilting (a) of the blade carrier relative to the carriage, a rotation of the rear arm of the push rod relative to the carriage, which rotation disengages the first pin (31) from the stop of stop (12).

8 - Safety knife according to claim 7 wherein the stopper comprises a tongue (14) or a shoulder (12d) prohibiting the return of the first pin (31) in engagement with the stopper (12) .

9 - Safety knife according to claim 7 or 8 for which the first pin (31), once disengaged from the stopper, is found in a cam path (15) or a gutter extending to a rear part of the trolley.

10 - Safety knife according to claim 9 wherein the cam path (15) comprises a profile adapted to bring the first pin (31) in alignment with the stopper (12), blade holder (20) in the retracted position .

1 1 - Safety knife according to claim 9 for which the gutter is constituted by a window (102) of the carriage (10 ') in which is positioned a spring arm (12b) carrying the stopper (12').

12 - Safety knife according to any one of the preceding claims wherein the carriage comprises a pusher (16) maneuvering protruding from the body through an opening (51) of the body.

13 - Safety knife according to any preceding claim wherein the carriage (10, 10 ') is connected to the body through a second spring (60) for returning the carriage in a rear position of rest.

14 - Safety knife according to any one of the preceding claims wherein the body comprises a stop (52, 52 ') for positioning the blade holder so as to engage the first pin (31) with the stopper (12). , 12 '). 15 - Safety knife according to any one of the preceding claims for which the carriage comprises a temporary stop (101, 101 ') adapted to retain the blade holder in the advanced position in the presence of a cutting force.

16 - Safety knife according to any preceding claim wherein the rails (1 1) for receiving the pins (21) are formed by windows in the carriage.

17 - Safety knife according to any one of claims 1 to 15 for which the rails (1 1 ') for receiving the pins are formed by grooves in the knife body.