Retractable blade knife

(74) Representative (s): Jean-Louis Thebault θ Improvements to knives with automatically retractable bla des.

FR 2 552 008 - A1 (57) l.'invention relates to improvements to knives with automatically retractable blades.

The object of the invention is a knife with a retractable blade of the cutter type comprising a blade 1 mounted to slide inside a handle 2a, 2b, a control means 13 of the blade and a return means thereof. ci in the retracted position, said knife being characterized in that the control means is constituted by a retractable mounted part 13, and by means 12, 6a to convert the stroke of said part into a movement of the blade 1 so that the depression of the part corresponds to the extraction of the blade, a hard point being provided at the start of the driving stroke of the part 13 .

Application to retractable blade cutters.

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- i IMPROVEMENTS TO BLADE KNIVES

AUTOMATICALLY RETRACTABLE

The present invention rel ates to a knife of the cutter type with a retractable blade automatically as soon as the pusher, handle or trigger for controlling the exit of the blade from the handle is released.

Cutters of the above type are already known comprising a sliding blade whose exit from the handle is controlled by pressure with the thumb on a lateral pusher on the handle, the pusher automatically returning to its initial position corresponding to the total retraction of the blade as soon as stops the pressure exerted on the pusher, thanks to a return spring arranged inside the handle.

This type of instrument has two notable drawbacks. On the one hand, they do not offer all the guarantees of safety when not in use, because they are not immune to an untimely partial exit of the blade from the handle, which can be dangerous. and cause injury for example when the knife is in the pocket.

On the other hand, they are not very practical to use because, in service, they require a non-negligible constant pressure of the thumb on said pusher in order to have the blade in the working position. This can be tiring in the long run and, moreover, cause problems for left-handers because the pusher is only accessible from one side of the knife handle.

The aim of the invention is to overcome these drawbacks by providing an automatic blade retraction system that is practical, effective and safe in all circumstances.

To this end, the invention relates to a knife with a retractable blade of the cutter type comprising a blade mounted to slide axially inside a handle, a means for manual control of the output of the blade and an automatic return means. the blade in the retracted position upon release. ment of action on said control means, said knife being characterized in that said control means is constituted by a retractable mounted part at least partially inside the handle and by means for converting the stroke of said part into a displacement of the blade in translation axially to the handle so that the depression of the part corresponds to the extraction of the blade, a hard point being provided at the start of the driving stroke of the part.

According to a first embodiment, said control part is constituted by a lever, or trigger, articulated at one end on the handle so that the angular movement of the free end of said lever, or trigger, results in said displacement in translation of the blade.

According to a second embodiment, said control part is constituted by a pusher mounted movable in translation perpendicular to the axis of the handle and parallel to the plane of the blade, said pusher comprising a wedge-shaped part capable of penetrating the handle. inside the handle and cooperating with a fixed stop piece inside the handle and with a blade holder mounted to slide axially inside the handle, elastic return means being provided to return said pusher and said blade holder to the rest position. '

Such a knife offers increased safety due to the hard point of safety which may possibly constitute a locking, provided at the start of the driving stroke of said pusher or trigger, this hard point practically excluding the untimely exit of the blade by hooking or accidental pressure. requesting the pusher or the trigger.

Furthermore, the knife according to the invention is particularly practical and efficient to use without any fatigue, because the blade is released by pressure, either with the fingers of the hand or with the palm, the _ 3 - 2552008 the full hand grip of the knife ensuring both a clean and effortless extraction of the blade and a perfect hold and maintenance in the effort of the knife.

Other characteristics and advantages will emerge from the following description of an embodiment of a knife according to the invention, description given by way of example only and with reference to the appended drawings in which: '

- Figure 1 shows schematically a longitudinal vertical sectional view of a knife according to the invention, in the rest position;

- Figure 2 shows the knife of Figure 1 substantially halfway down the control trigger;

- Figure 3 shows the knife of Figure 1 in the working position, the trigger being fully depressed;

- Figure 4 shows a section along line IV-IV of the knife of Figure 3;

- Figure 5 shows schematically a longitudinal vertical cbupe view of an alternative embodiment of a knife according to the invention, in the rest position;

- Figure 6 shows the knife of Figure 5 in working position, the trigger being fully depressed, and

- Figure 7 schematically illustrates another embodiment.

The knife shown in Figures 1 to 4 is a cutter type blade 1 retractable inside a hollow handle 2 consisting of two half-handles 2a and 2b assembled using a screw system 3 and nut 4 passing through the handle 2 in its central part. In Figures 1 to 3 the half sleeve 2b is removed.

The handle 2 defines in its front part means 5 for receiving and guiding axially to the handle of the blade 1, which is carried in the usual way by a slide 6 mounted to move.

The blade 1 is positioned on the slide 6 using centering pins 7 and stop.

The slider 6 has a trapezoidal shape and consists (figure 4) of a thin plate with an I-section pre_ 4 - 2552008 feeling two guide heels 8 of the slider 6 in two parallel guide grooves 5 formed between the two half-sleeves 2a and 2b. .

The slide 6 can move between two extreme positions, one of the blade 1 output in the working position (Figure 3) and, the other, of full retraction of the blade in the handle (Figure 1). '

The slider 6 is automatically returned to the retracted position of the blade 1 by a helical spring 9 anchored, at one end, on a projection 10 integral with the half-handle 2a and, at the other end, on a projection 11 integral with the slide 6.

The rear edge 6a of the slide is shaped. in an inclined ramp capable of cooperating with a pusher, consisting of a boss 12 shaped at the end of a lever or trigger 13 articulated at the rear of the handle about an axis 14.

The trigger 13 is arranged so as to retract almost entirely inside the handle in a space provided for this purpose between the two half-sleeves 2a, 2b.

In the rest position of the trigger 1.3, the latter (Figure 1) protrudes as far as possible out of the handle and abuts by a projection 15 against a stop rim 16 formed in the handle. In this position, the boss 12 is at the height of one of the ends of the inclined ramp 6a and the blade 1 is completely retracted into the handle.

By pressing the trigger 13 with the fingers of the hand gripping the knife (or with the palm if the trigger 13 was placed on the other side of the handle), the boss 12 presses on the ramp and forces the slide 6 towards the outside against the return force of the spring 9. At the end of the travel of the trigger 13 (figure 3) the boss 12 has reached the other end of the ramp 6a and comes into abutment against the opposite wall of the handle .

In this position the blade 1 is extended to the maximum and the outer edge 13a of the trigger is substantially level with the orifice of the passage made in the handle for the trigger. '

According to another characteristic of the device according to the invention, the trigger 13 comprises a

- 5 - 2552008 safety in rest position (trigger fully extended from the handle, figure 1) formed by a hard point at the start of the trigger depression stroke. This hard point requires a momentary increase in pressure on the trigger 13 in order to overcome the resistance of the hard point, after which the resistance to sinking comes only from the spring 9. This hard point can be provided more or less resistant and, preferably, can constitute a real locking requiring special intervention in order to be able to drive in the trigger.

It is the latter variant which is shown in Figures 1 to 3. For this purpose, the end of the trigger 13 is provided with an elastic tongue 17 for locking, directed towards the handle and whose rounded end 17a 15 is capable of cooperating with a locking hollow 18 formed at the edge of the passage opening in the handle of the trigger.

In the rest position (figure 1) the tongue 17 bears on its end 17a in the recess 18 and prevents the sinking of the trigger 13. To allow the latter it is necessary to press (arrow 19) on the tongue 17 to bring it closer. of the trigger and release the end 17a of the recess 18. Thus, the. tab 17 escapes from the hollow 18 by depressing the trigger 13.

This prior action on the tongue 17 can be done with the index finger of the hand gripping the knife.

The depression of the trigger is practically not hampered by the tongue 17 which is arranged so as not to come into contact with the slide 6.

3G One can imagine many other systems for locking the trigger without, of course, departing from the scope of the invention.

Figures 5 and 6 illustrate an alternative embodiment of the elastic system of Figures 1 to 3 according to which the tongue 17, for example molded at the same time as the trigger 13 from a suitable plastic material, is replaced by a curved leaf spring 20, anchored at one end in the trigger and of which the curved free end 20a cooperates with a locking hollow 18 similar to that of FIGS. 1 to 3.

FIG. 7 schematically illustrates another embodiment of a knife according to the invention according to which the part for controlling the movement of the blade 1 is constituted by a pusher 21 partially engaged in the handle 22 and movable in translation perpendicular to the longitudinal axis of the handle.

The plane in which the pusher 21 moves is parallel to the plane of the blade, just like that in which the trigger 13 moves in the previous embodiments.

The pusher 21 comprises an external part 21a and a part 21b capable of penetrating into the handle 22, in the form of a trapezoidal wedge, the inclined rear flank 21c of which cooperates with a corresponding inclined face 23 provided on a part 24 fixed inside the handle.

The front inclined flank 21d of the wedge 21b cooperates with an inclined face 25 of a blade holder 26 similar to the blade holder 6 of the previous embodiments.

A return spring 27 is interposed between the part 24 and the blade holder 26.

The pusher 21 moves through a passage window 28.ménée for this purpose in the wall of the. handle 22.

The depression of the pusher 21 causes the partial exit of the blade holder 26 against the return force of the spring 27.

The release of the pusher 21 causes, by the action of the spring 27, the retraction of the blade holder 26 and pushes the pusher towards the outside of the handle, retained of course by a stopper (not shown). .

This device may advantageously be provided with a safety lock in the non-use position of the type shown in Figures 1 or 5 or of a similar type.

The knife of the invention thus offers absolute safety when not in use and especially when it is in the pocket. It is also particularly handy and efficient thanks to its excellent grip and its secure hold in the working position, mainly because the control member (13,21) moves substantially in the median plane of the handle, parallel to the plane of the blade. 1 and can therefore be squeezed easily and effectively by the fingers or the palm of the hand.

Finally, the invention is obviously not limited to the embodiments shown and described above but on the contrary covers all the variants thereof, in particular as regards the shapes and arrangements of the trigger 13 or of the control pusher 21 as well as the nature and arrangement of the locking means of the latter in the rest position.