FR3086795A1 - SWITCH COMPRISING A DEFORMABLE ACTUATOR - Google Patents

Abstract

The present invention relates to a switch (100) comprising a barrel (1) and an actuator (2) integral with the barrel, the actuator being adapted to deform under the action of a user, mainly characterized in that the actuator ( 2) comprises an actuator body (20) and a transparent or translucent film (21) which covers the actuator body, said film having an internal face (210) in contact with the actuator body, and an external face (211) opposite the internal face, said film being deformable with the actuator body, and in that the film (21) comprises a visual pattern (212) on its internal face (210) and visible through its external face (211).

Description

SWITCH COMPRISING A DEFORMABLE ACTUATOR

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a switch comprising a deformable actuator, as well as to a method for manufacturing such a switch.

STATE OF THE ART

Industrial machine switches are widely used in industry. They are connected to the control system of the machine, and allow an operator to interact with the control system, in particular to stop the operation of the machine in the case of an emergency stop switch for example.

There are different mechanisms for actuating a switch (rocker actuator, rotary wheel actuator, deformable membrane, etc.).

A particular type of switch includes a switch body, called a "barrel", surmounted by an actuator configured to deform when it is acted upon by an operator.

When the operator presses the switch actuator, the actuator deforms as it sinks into the barrel. An instruction corresponding to the function of the switch is sent to the control system which then controls the various effector members of the machine according to the instruction received.

The actuator generally comprises a pattern, such as a word, part of a word or a symbol making it possible to identify its function, such as the word "STOP" in the case of an emergency stop switch for example. . This pattern can be made on the exposed face of the actuator, that is to say the face on which the operator comes to press. For example, the pattern can be stamped or screen printed. Alternatively, the actuator is covered with a layer of paint and then the paint is removed locally by laser engraving to form the pattern.

Such an actuator must meet a certain number of technical specifications, such as resistance to scratching, resistance to abrasion, resistance to chemical attack, in order to guarantee the maintenance of its integrity throughout its use.

However, according to the specifications imposed, some of these specifications are difficult to meet, leading to a risk of damage or gradual erasure of the pattern, which leads to a decrease in its readability.

BRIEF DESCRIPTION OF THE INVENTION

An object of the invention is to provide a switch enabling the drawbacks described above to be overcome.

To this end, the invention relates to a switch comprising a barrel and an actuator integral with the barrel, the actuator being adapted to deform under the action of a user. The switch is mainly characterized in that the actuator comprises an actuator body and a transparent or translucent film which covers the actuator body, said film having an internal face in contact with the actuator body, and a face external opposite to the internal face, said film being deformable with the actuator body, and in that the film comprises a visual pattern on its internal face and visible through its external face.

The pattern is made on the inside of the film. It is visible to the operator through the transparent or translucent material of the film. The film can be "transparent" in that it lets light through and allows the operator to distinguish the elements located on the other side of the film from it, or "translucent" in that it lets pass the light without however allowing the operator to distinguish the elements located on the other side of the film from him. The pattern on the inner side of the film is visible to the user who is viewing the film from its exposed side, and whether the film is transparent or translucent.

The realization of the pattern on the internal face of the film avoids any contact between the operator and the pattern. The physical integrity of the pattern is thus preserved when the switch is used, throughout the life of the film.

According to other aspects, the switch has the following different characteristics taken alone or according to their technically possible combinations:

the actuator body is molded between the barrel and the film. Overmolding is relatively simple to implement on an industrial scale, and the actuator body obtained follows the shape of the overlying film, which allows the actuator body and the film to deform in an integral manner when the operator presses on the actuator;

the visual motif is a screen-printed motif on the internal face of the film. Screen printing has the advantage of being both quick to implement and of representing a relatively low financial cost compared to other techniques, such as inkjet printing, spraying, or even stamping. ;

the actuator body is made of an injectable thermoplastic elastomer material, such as for example a thermoplastic polyurethane (TPU), or a styrene-ethylene-butylene-styrene copolymer (SEBS). These elastomers have elastic properties which are particularly suitable for their use in a switch actuator, in addition to being injectable, which makes it possible to manufacture the actuator body by injection-molding;

the film is made of a thermoplastic polymer material, such as for example a polyurethane (PU). These thermoplastic polymers give the film good mechanical strength in order to protect the actuator body from the outside environment, while preserving the flexibility of the film.

The invention also relates to a method for manufacturing a switch as described above, mainly characterized in that it comprises the following steps:

• the supply of a transparent or translucent deformable film, and of a switch barrel, • the positioning of the film and the barrel opposite one another in a mold comprising a mold impression of the body actuator, • overmolding of the actuator body on the barrel and the film by injection of a polymer material constituting said actuator body into the mold, in order to form the actuator.

The method of the invention thus makes it possible to form the actuator in a mold, according to known technology "in mold", but differs from known methods based on this technology in that the actuator body is molded on a flexible surface , which is that of the film. This gives good adhesion of the film to the actuator body.

According to other aspects, the process has the following different characteristics taken alone or according to their technically possible combinations:

the film is shaped prior to overmolding of the actuator body, so that the shape of said film corresponds to the shape of the actuator. Thus, the actuator body directly takes the form of the film during overmolding;

the film is shaped by thermoforming;

the method further comprises, prior to the shaping of the film, the production of a visual pattern on the internal face of the film;

the visual motif is produced by screen printing;

the visual motif is produced by etching;

the polymeric material is injected between the barrel and the film in a lateral direction relative to the barrel;

the polymer material constituting the actuator body comprises an injectable thermoplastic elastomer, such as for example a thermoplastic polyurethane (TPU), or a styrene-ethylene-butylene-styrene copolymer (SEBS);

the polymer material constituting the film comprises a thermoplastic polymer, such as for example a polyurethane (PU).

DESCRIPTION OF THE FIGURES

Other advantages and characteristics of the invention will appear on reading the following description given by way of illustrative and nonlimiting example, with reference to the following appended figures:

Figures 1A and 1B show sectional views of a switch according to an embodiment of the invention, which illustrate the deformation of the actuator when pressure is exerted by an operator on the latter;

FIG. 2 represents a plan view of a film of thermoplastic polymer in which a pattern is produced;

FIG. 3 represents a perspective view of a film shaped in a tool so as to form the profile of the actuator;

FIGS. 4A, 4B, and 4C represent schematic views which illustrate the overmolding of the actuator body on the film and the gun of the switch;

FIG. 5 represents a sectional side view of the switch during the clipping of the film;

FIG. 6 shows in section of a switch obtained after overmolding of the actuator body and trimming of the film.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the switch according to the invention is shown in Figures 1A and 1B.

With reference to FIGS. 1A and 1B, the switch 100 comprises a barrel 1 as well as a deformable actuator 2 secured to the barrel. The actuator 2 comprises an actuator body 20 mounted on the barrel, as well as a film 21 which covers the actuator body.

Barrel 1 is a classic part of a switch. It constitutes the body of the switch, and serves as a support for the actuator.

The barrel 1 is in the form of a hollow cylindrical body whose internal volume 11 is delimited by a side wall 10. The internal volume 11 contains mechanical and electronic elements, not shown, allowing the switch to communicate with the control system of an industrial machine, so that the operator can interact with the control system by pressing or releasing the switch.

The base of the barrel is adapted to be physically connected to the machine. The top of the barrel is advantageously provided with a peripheral edge 12 making it possible to improve the grip of the actuator body 20 on the barrel 1.

The actuator body 20 is arranged between and in contact with the barrel 1 and the film 21. Preferably, the actuator body is molded between the barrel and the film.

The actuator body 20 is hollow and defines an internal volume 201 which communicates with the internal volume 11 of the barrel. It comprises a central part 202 and a peripheral part 203 arranged on the periphery of the top of the barrel, in particular on the edge 12 of the barrel.

The actuator body 20 is flexible and configured to deform elastically by pressure exerted by the operator, illustrated by the arrow F in FIG. 1B. In particular, at least the central part 202 of the actuator body is deformable, it being understood that the pressure of the operator is exerted on said central part, when the switch is actuated.

To this end, the actuator body 20 is preferably made from a thermoplastic elastomer material, and more preferably from a thermoplastic elastomer material chosen from a thermoplastic polyurethane (TPU), or a styrene-ethylene-butylene-styrene copolymer (SEBS). These thermoplastic elastomers have the advantage of being flexible and injectable, which makes them particularly suitable for the manufacture of the switch by injection-molding of the actuator body.

The actuator body 20 is preferably curved and bent outward. This facilitates the deformation of the actuator body, the curvature of the external face of which is reversed towards the inside of the switch in the direction of the barrel, as illustrated in FIGS. 1A and 1B.

The film 21 is transparent or translucent. It is arranged on and in contact with the actuator body 20 so that the internal face 210 of the film covers the external face of the actuator body. The outer face 211 of the film is exposed and configured to come into contact with the user's hand. The film 21 includes a central part 212 which covers the central part 202 of the actuator body, and a peripheral part 213 which covers the peripheral part 203 of the actuator body. Thus, the film 21 follows the shape of the actuator body 20. In particular, when the actuator body is curved, the film is also curved.

The film 21 is flexible and configured to deform with the actuator body 20 by pressure exerted by the operator, while protecting the actuator body from the external environment, that is to say in particular from shocks , abrasion, or chemicals. In particular, at least the central part 212 of the film is deformable, it being understood that the pressure of the operator is exerted on said central part, when the switch is actuated.

To this end, the film 21 is preferably made from a thermoplastic polymer material, which is stiffer than the thermoplastic elastomer material of the actuator body, and more preferably from a thermoplastic polymer material chosen from polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyethylene (PE) and polyurethane (PU). These thermoplastic polymers give the film good mechanical strength in order to protect the actuator body from the outside environment, while preserving the flexibility of the film.

The film 21 is a thin film, the thickness of which is preferably between 150 μm and 300 μm, and more preferably between 200 μm and 250 μm.

The film 21 comprises a visual pattern 214 on its internal surface 210. This pattern is visible to the operator, who is facing the external face 211 of the film, and sees the pattern through said external face, thanks to the transparent nature or translucent film. It is specified that although a translucent film does not allow the operator to see what is behind the film, that is to say beyond the internal face of the film, such a film allows the operator to see the pattern made on the inside of the film.

The pattern 214 can be for example a word, a part of a word, a symbol, a drawing, or any other visual element usually enabling the operator to know the function of the switch without having to press it. In the case of an emergency stop switch, the reason may for example consist of the word "STOP", clearly indicating to the operator that actuation of the switch causes the machine to stop.

The pattern 214 is preferably produced by screen printing, which is a rapid technique to implement and which has a relatively low financial cost. The pattern can be produced by any other suitable technique, such as for example inkjet printing, spraying, stamping, engraving such as laser or chemical engraving.

Producing the pattern 214 on the internal face 211 of the film makes it possible to physically isolate said pattern from the operator. When the operator presses the switch, his hand contacts the outside of the film, which preserves the integrity of the pattern on the inside. The pattern is also protected from the outside environment. In particular, the film seals the switch so that water or any other liquid such as a product or a chemical composition cannot pass through the film and therefore does not reach the pattern or the body. nor the internal volume of the barrel.

Referring to Figure 1B, when the operator exerts pressure on the actuator 2, his hand comes into contact with the outer surface 211 of the film. The film 21 and the actuator body 20 are deformed integrally in the direction of the force, illustrated by the arrow F, towards the inside of the switch in the direction of the barrel 1.

The central parts 202, 212 of the actuator body and of the film have a curvature oriented towards the inside of the switch in the direction of the barrel, and the internal volume 201 of the actuator body is reduced.

When the operator releases the pressure, the actuator body 20 returns to its initial position illustrated in FIG. 1A due to its elasticity. The return of the actuator body to the initial position causes the film 21 to return to the initial position.

The switch can then be actuated again in the same manner as what has just been described.

An embodiment of the method for manufacturing the switch 100 will now be described with reference to FIGS. 2 to 6.

A first step in the process consists in providing the film 21 and the barrel 1.

According to one embodiment, a pattern is produced on one of the faces of the film which will constitute the internal face of the film within the switch.

FIG. 2 illustrates a thermoplastic polymer film in which a trumpet symbol 214 has been screen printed on the internal face.

The film is then shaped so that the shape of the film matches the shape of the actuator. To obtain the actuator of FIG. 1A, it is a question of forming a hollow and curved film.

The film can be formed by thermoforming in a tool suitable for this purpose, as illustrated in FIG. 3. On the film 21 illustrated, the symbol "AUX" was screen printed on one side of the film before it was formed.

The mold being open, the film 21 is then positioned in a first part 31 of the mold, as illustrated in FIG. 4A. The barrel 1 is inserted on a second part 32 of the mold comprising an injection channel 33, 34, as illustrated in FIG. 4B, so that the injection channel opens into the internal volume 11 of the barrel, in the vicinity of the internal face 210 of the film.

Once positioned in the mold, after closing of said mold, the film 21 and the barrel 1 are located opposite one another, and define with the mold a molding imprint 30 of the actuator body 20, like the illustrates Figure 4C.

The polymeric material is then injected from the injection channel into the mold cavity to overmold the actuator body on the barrel and the film.

According to a preferred embodiment, a lateral injection of the polymer is carried out, so that the polymer circulates in a first portion 34 of the injection channel orthogonal or oblique with respect to the axis of the switch, before circulating in a second portion 33 of the injection channel parallel to the axis of the switch. The positioning of the first portion 34 along the axis of the switch is adjusted so as to reduce the length of injection into the mold, that is to say to minimize the path of circulation of the polymer before reach the molding footprint 30. This reduces the shearing of the polymer against the walls of the injection channel and improves the uniformity and speed of filling of the molding impression.

According to a variant of this embodiment, a lateral injection of the polymer is carried out directly in the vicinity of the film. In other words, the first portion 34 of the injection channel is located directly in the vicinity of the film. In doing so, the length of injection into the mold is minimal, and the shear is then greatly reduced since it is present only in the vicinity of the molding footprint.

A trimming step, illustrated in FIG. 5, makes it possible to cut the periphery of the film which is not overmolded on the actuator body and to obtain at the end of process 5 the switch illustrated in FIGS. 1A-B and 6.

Claims (18)

1. Switch (100) comprising a barrel (1) and an actuator (2) integral with the barrel, the actuator being adapted to deform under the action of a user, characterized in that the actuator (2) comprises a actuator body (20) and a transparent or translucent film (21) which covers the actuator body, said film having an inner face (210) in contact with the actuator body, and an opposite outer face (211) on the internal face, said film (21) being deformable with the actuator body (20), and in that the film (21) comprises a visual pattern (214) on its internal face (210) and visible through its external face (211). 2. Switch (100) according to claim 1, wherein the actuator body (20) is molded between the barrel (1) and the film (21). 3. Switch (100) according to one of claims 1 or 2, wherein the visual pattern (214) is a screen-printed pattern on the inner face (210) of the film. 4. Switch (100) according to one of the preceding claims, wherein the actuator body (20) is made of an injectable thermoplastic elastomeric material. 5. Switch (100) according to claim 4, wherein the injectable thermoplastic elastomeric material of the actuator body (20) is chosen from: a thermoplastic polyurethane (TPU), a styrene-ethylene-butylene-styrene copolymer (SEBS). 6. Switch (100) according to any one of the preceding claims, wherein the film (21) is made of a thermoplastic polymeric material. 7. Switch (100) according to claim 6, wherein the thermoplastic polymeric material of the film (21) comprises a polyurethane (PU). 8. Method for manufacturing a switch (100) according to any one of the preceding claims, characterized in that it comprises the following steps: supplying a transparent or translucent deformable film (21), and a switch barrel (1), positioning the film (21) and the barrel (1) facing each other in a mold (3) comprising an imprint (30) for molding the actuator body (20), the overmolding of the actuator body (20) on the barrel (1) and the film (21) by injection of a polymeric material constituting said actuator body in the mold, in order to form the actuator (2). 9. The manufacturing method according to claim 8, wherein the film (21) is shaped prior to overmolding of the actuator body (20), so that the shape of said film corresponds to the shape of the actuator. . 10. The manufacturing method according to claim 9, wherein the film (21) is shaped by thermoforming. 11. The manufacturing method according to one of claims 9 or 10, further comprising, prior to the shaping of the film (21), the production of a visual pattern (214) on the internal face (210) of the film. . 12. The manufacturing method according to claim 11, wherein the visual pattern (214) is produced by screen printing. 13. The manufacturing method according to claim 11, wherein the visual pattern is produced by etching. 14. The manufacturing method according to any one of claims 8 to 13, wherein the polymeric material is injected between the barrel (1) and the film (21) in a lateral direction relative to the barrel. 15. The manufacturing method according to any one of claims 8 to 14, wherein the polymeric material constituting the actuator body (20) comprises an injectable thermoplastic elastomer. 16. The manufacturing method according to claim 15, wherein the injectable thermoplastic elastomer is chosen from: a thermoplastic polyurethane (TPU), a styrene-ethylene-butylene-styrene copolymer (SEBS). 17. Manufacturing process according to any one of the preceding claims, in which the polymer material constituting the film (21) comprises a thermoplastic polymer. 18. The manufacturing method according to claim 17, wherein the thermoplastic polymer comprises a polyurethane (PU).