EP4071777B1 - Electrical switch - Google Patents

Description

Technical field of the invention

Disclosed is a high-reliability, long-life electrical switch that provides excellent tactile feel upon axial actuation.

The invention relates more particularly to an electrical switch in which the tactile sensation results from the cooperation of an elastically deformable ring, and for example of the free end turn of a helical compression spring with a ramp of the upper rod of actuation which is crossed by the elastic ring which deforms radially during the actuation stroke of the switch.

Technical background

• une embase inférieure, ou boîtier 6 ;
• une tige supérieure d'actionnement 1, ou poussoir, comportant un tronçon 18 dont la paroi latérale cylindrique est guidée axialement en coulissement dans un alésage de guidage formé dans l'embase inférieure ;
• un organe élastique 4 de rappel de la tige supérieure d'actionnement vers une position haute de repos,

The document FR-A1-2420834 proposes a design of an electric switch, also called electric switch, with tactile effect with axial actuation comprising:

• a lower base, or housing 6;
• an upper actuating rod 1, or pusher, comprising a section 18 whose cylindrical side wall is guided axially by sliding in a guide bore formed in the lower base;
• an elastic member 4 for returning the upper actuating rod to a high rest position,

• qui est agencé dans un logement périphérique formé dans ladite paroi latérale ;
• qui est traversé axialement par ledit tronçon de la tige supérieure d'actionnement ;
• qui, lors de la course d'actionnement de la tige supérieure d'actionnement 1, est en appui axialement vers le bas contre une face fixe de butée 18 appartenant à l'embase inférieure 6 ;
• et qui, lors de la course d'actionnement de la tige supérieure d'actionnement 1, coopère avec un profil de came 20 formé dans ladite paroi latérale qui le déforme radialement pour produire une résistance élastique à l'actionnement de la tige supérieure d'actionnement.

Switch in which, under the action of an actuation force applied to the upper actuation rod and against the force exerted by the elastic return member, the upper actuation rod 1 moves axially with respect to the lower base 6, according to a stroke actuation, towards an active low position to modify the state of at least one electrical switching channel,
and comprising an elastic ring 17:

• which is arranged in a peripheral housing formed in said side wall;
• which is traversed axially by said section of the upper actuating rod;
• which, during the actuating stroke of the upper actuating rod 1, bears axially downwards against a fixed abutment face 18 belonging to the lower base 6;
• and which, during the actuation stroke of the upper actuation rod 1, cooperates with a cam profile 20 formed in said side wall which deforms it radially to produce an elastic resistance to the actuation of the upper actuation rod actuation.

The purpose of such a design is to solve the problem of the user's uncertainty as to the reality of the implementation of the function which he has ordered by means of the switch by acting on the upper actuating rod.

This is obtained by the tactile sensation that he perceives when he acts on the upper actuating rod.

This principle has in particular been implemented by the company C&K in the design of the reference push-button switch “K12S”.

The last free end coil of the return spring interacts with the ramp of the actuator which creates several forces, including a radial force which causes the opening of the last coil and which determines the mechanical characteristics of the switch, and an axial force which pushes the last turn of the return spring axially downwards, in the direction of the actuating stroke, this last turn being in principle stopped axially by the fixed annular abutment face belonging to the lower base.

By the combination of these two forces, the last coil is pushed radially outwards.

There is a risk that the last coil of the spring is wedged between the ramp of the upper actuating rod and the lower base, which can then lead to a significant increase in the actuation force and/or an uncontrolled variation in the actuation force and an increase in the range of values of this actuation force in the technical specification of the product.

Summary of the invention

• l'alésage de guidage comporte une série de nervures axiales dont chacune fait saillie radialement vers l'intérieur de l'alésage de guidage et est reçue en coulissement dans une rainure axiale complémentaire formée dans ladite paroi latérale ; et
• ladite surface fixe de butée est constituée par les facettes radiales d'extrémité supérieure de chaque nervure axiale.

In order to remedy this drawback, the invention proposes an electrical switch of the type mentioned above, characterized in that:

• the guide bore comprises a series of axial ribs, each of which projects radially towards the inside of the guide bore and is slidably received in a complementary axial groove formed in said side wall; And
• said fixed abutment surface is constituted by the upper end radial facets of each axial rib.

• ledit logement est délimité axialement vers le bas par un épaulement radial inférieur et vers le haut par ledit profil de came ;
• ledit profil de came est un tronçon de cône dont le sommet est orienté axialement vers le bas formant une rampe avec laquelle coopère l'anneau élastique ;
• chaque rainure axiale formée dans ladite paroi latérale s'étend axialement vers le haut au-delà dudit profil de came ;
• ledit organe élastique de rappel est un ressort hélicoïdal de compression qui est traversé axialement par ledit tronçon de la tige supérieure d'actionnement, et dont la spire inférieure constitue ledit anneau élastique ;
• ledit ressort est monté comprimé axialement entre les facettes radiales d'extrémité supérieure de chaque nervure axiale et un épaulement radial supérieur qui délimite axialement ledit tronçon vers le haut.

According to other characteristics of the invention:

• said housing is delimited axially downwards by a lower radial shoulder and upwards by said cam profile;
• said cam profile is a cone section whose apex is oriented axially downwards forming a ramp with which the elastic ring cooperates;
• each axial groove formed in said side wall extends axially upward beyond said cam profile;
• said elastic return member is a helical compression spring which is traversed axially by said section of the upper actuating rod, and whose lower turn constitutes said elastic ring;
• said spring is mounted compressed axially between the upper end radial facets of each axial rib and an upper radial shoulder which axially delimits said section upwards.

Brief descriptions of figures

• [Fig.1] - la figure 1 est une vue latérale éclatée d'un exemple de réalisation d'un commutateur électrique selon l'invention ;
• [Fig.2] - la figure 2 est une vue en coupe, par un plan longitudinal et vertical médian, du commutateur de la figure 1 ;
• [Fig.3] - la figure 3 est une est une vue en coupe, par un plan vertical et transversal médian, du commutateur de la figure 1 ;
• [Fig.4] - la figure 4 est une est une vue en perspective éclatée de l'embase inférieure, du ressort de rappel et de la tige supérieure d'actionnement du commutateur de la figure 1 ;
• [Fig.5] - la figure 5 est une vue en perspective de la tige supérieure d'actionnement du commutateur de la figure 1 ;
• [Fig.6] - la figure 6 est une vue en perspective de la tige supérieure d'actionnement et du ressort de rappel du commutateur de la figure 1 ; [Fig.7] - la figure 7 est une vue axiale en bout de la tige supérieure d'actionnement du commutateur de la figure 1 ;
• [Fig.8A] - la figure 8A est une vue en coupe par un plan longitudinal et transversal médian de l'embase inférieure, du ressort de rappel et de la tige supérieure d'actionnement du commutateur de la figure 1 avec la tige supérieure d'actionnement représentée en position haute de repos ;
• [Fig.8B] - la figure 8B est une vue analogue à celle de la figure 8A sur laquelle la tige supérieure d'actionnement est représentée en position basse active, sans le ressort de rappel ;
• [Fig.9] - la figure 9 est une vue partielle en coupe par un plan longitudinal et transversal selon la ligne 9-9 de la figure 8A ;
• [Fig.10] - la figure 10 est une vue analogue à celle de la figure 9 qui représente un second exemple de réalisation du ressort de rappel dont la spire d'extrémité inférieure est de forme circulaire.

Other characteristics and advantages of the invention will appear during the reading of the detailed description which will follow for the understanding of which reference will be made to the appended drawings in which:

• [ Fig.1 ] - there figure 1 is an exploded side view of an embodiment of an electrical switch according to the invention;
• [ Fig.2 ] - there picture 2 is a sectional view, by a median longitudinal and vertical plane, of the switch of the figure 1 ;
• [ Fig.3 ] - there picture 3 is a sectional view, by a median vertical and transverse plane, of the switch of the figure 1 ;
• [ Fig.4 ] - there figure 4 is an exploded perspective view of the lower header, return spring, and upper switch actuating rod of the figure 1 ;
• [ Fig.5 ] - there figure 5 is a perspective view of the upper switch actuating rod of the figure 1 ;
• [ Fig.6 ] - there figure 6 is a perspective view of the upper actuating rod and switch return spring of the figure 1 ; [ Fig.7 ] - there figure 7 is an axial end view of the upper switch actuating rod of the figure 1 ;
• [ Fig.8A ] - there figure 8A is a cross-sectional view by a median longitudinal and transverse plane of the lower base, the return spring and the upper actuating rod of the switch of the figure 1 with the upper actuating rod shown in the high rest position;
• [ Fig.8B ] - there figure 8B is a view analogous to that of the figure 8A on which the upper actuating rod is shown in the active low position, without the return spring;
• [ Fig.9 ] - there figure 9 is a partial sectional view along a longitudinal and transverse plane along line 9-9 of the figure 8A ;
• [ Fig.10 ] - there figure 10 is a view analogous to that of the figure 9 which represents a second embodiment of the return spring whose lower end turn is circular.

Detailed description of the invention

For the description of the invention and the understanding of the claims, the vertical, longitudinal and transverse orientations according to the reference V, L, T indicated in the figures whose longitudinal axes L and transverse T extend in a horizontal plane.

By convention, the vertical axis V is oriented from bottom to top.

In the following description, identical, similar or analogous elements will be designated by the same reference numerals.

First example of realization

In the example that follows, the electrical switch 20 has a general design symmetry with respect to the median vertical and longitudinal plane, and with respect to the median vertical and transverse plane.

Vertically from bottom to top, the electrical switch 20 - which is notably illustrated in particular in figures 1 to 3 - comprises a lower base 22 and an upper actuating rod 24 which is slidably mounted, along the main vertical axis A with respect to the lower base 22.

The lower base 22, forming a box, is closed at its upper part by an upper actuating cover 26 which is mounted to slide axially with respect to the lower base 22.

The electrical switch 20 further comprises a helical compression spring 28 which is interposed axially between the upper actuating rod 24 and the lower base 22, and a flexible lateral sealing membrane 30 which cooperates with the upper cover 26 and the lower base 22.

The electrical switch 20 also comprises two elastically deformable electrical contact blades 32 and 34, each of which is connected to a connection terminal 36. Thus, without limitation, the electrical switch 20 is here of the normally closed type in which, in l absence of actuation, the two electrical contact blades 32 and 34 are in mutual elastic support and establish the voice of electrical switching between two connecting terminals 36 associated.

By way of non-limiting example, the electrical switch 20 is of the luminous type and comprises for this purpose a light source 38 which is for example a light-emitting diode and which is connected to connection terminals 40 for its power supply.

The lower base 22 is produced by overmoulding in plastic material around the electrical connection elements of the electrical contact blades 32 and 34 and of the light source 38.

The lower base 22 is here in the form of a cylindrical box with axis A, the lower face 42 of which comprises a pin 44 for its attachment to a support element (not shown) such as for example a printed circuit board. .

The main body 46 of the lower base 22 delimits a lower cavity 48 open vertically upwards and an upper cavity 50 of generally circular cylindrical shape also open upwards which is delimited by the upper edge 52 of the lower base 32.

The two cavities 48 and 50 are delimited relative to each other by a horizontal radial face 49 which is oriented vertically upwards.

The electrical contact blades 32 and 34 extend vertically upwards inside the lower base 22 from the bottom 47 of the lower cavity 48. The light source 38 is also arranged in the bottom 47 of the lower cavity 48 .

The side wall 54 of the lower base 22 comprises a lower radial groove 56 in which is elastically fitted a complementary annular rib 58 of the sealing membrane 30, and two vertical and diametrically opposed axial grooves 60, closed at their upper ends. .

The actuating top cover 26 includes a horizontal top plate 62 and a cylindrical tubular side wall 64 which includes two diametrically opposed hooks 66 which extend generally inward and each of which is received in an associated groove 60 of the side wall. 54 of the lower base 22.

The upper plate 62 is pierced centrally and is here closed by a translucent or transparent plate 68 which can for example be colored and/or comprise a pattern and which can make it possible to visualize the switching on of the light source 38.

The internal lower face 70 of the upper plate 62 delimits a housing 72 open axially downwards and which comprises a radial finger for angular indexing 74.

The side wall 63 of the upper plate 62 comprises an internal radial groove 76 in which is elastically fitted a complementary annular bead 78 of the sealing membrane 30.

The lower cavity 48 of the lower base 22 comprises an axial guide bore 80 which is in the form of a series of concave sections which, without limitation, are here six in number.

The axial guide bore 80 thus formed extends vertically upwards from the bottom 47 and emerges axially in the face 49.

In accordance with the invention, the lower cavity 48 of the lower base 22 also comprises a series of vertical axial ribs 82, each of which extends radially inwardly projecting with respect to the concave cylindrical surface of the guide bore. 80.

On a non-limiting basis, and as can be seen in particular at figure 9 , the ribs 82 are eight in number and comprise two pairs of upper and lower ribs and two lateral ribs, transversely opposed.

Each rib 82 is delimited axially upwards by a radial upper end face 84 which is coplanar with face 49.

Thus, within the meaning of the invention, the eight facets 84 are abutment facets each constituting a portion of a horizontal abutment face is oriented vertically upwards for the downward axial support of the return spring 28.

The lower cavity 48 of the lower base 22 further comprises four clearances 86 arranged angularly at ninety degrees of angle.

The upper actuating rod 24 is a molded plastic part consisting essentially of a hollow tubular body 90 which is delimited by an internal concave cylindrical wall 92 and by a convex cylindrical side wall 94.

At its upper part, the body 90 is extended by an upper cylindrical radial plate 96 which is received in the housing 72 and which comprises an angular indexing notch 97 in which is received the indexing pin 74 of the actuation cover 26 .

Inside the tubular body 90, the upper actuating rod 24 comprises two diametral plates 98 and 100 which are capable of acting on electrical contact elements.

In the example illustrated in the figures, it is the diametral plate 98 which is capable of cooperating with the two electrical contact strips 32 and 34 to move them longitudinally apart from each other in order to interrupt the electrical switching path. with which they are associated.

Thus, considering the rest position illustrated in picture 2 , an axial downward movement of the plate 98 causes an opening of the electrical contact formed by the two electrical contact elements 32 and 34 on which it acts by elastically deforming them to separate them from each other.

Such actuation is performed by acting on the upper actuation cover 26 which pushes axially on the upper radial plate 96 of the upper actuation rod 24 to move the latter axially downwards with respect to the lower base 22 and therefore relative to the electrical contact elements 32 and 34.

The side wall 94 of the upper actuator rod 24 extends axially from the lower annular radial face 102 of the radial plate 96 to the lower axial end annular radial face 104.

The side wall 94 of the upper actuating rod 24 comprises an internal radial groove 106 which is delimited by a convex cylindrical bottom wall 108.

The groove 106 is delimited axially upwards by a frustoconical upper radial shoulder 110 whose apex is oriented downwards and which constitutes a connecting ramp between the bottom wall 108 of the radial groove 106 and the convex side wall 94 of the upper actuating rod 24.

The groove 106 is delimited axially upwards by a lower radial shoulder 112 which is delimited axially by a radial face 114 oriented axially upwards.

In accordance with the teachings of the invention, the side wall 94 of the upper actuator rod 24 has a series of vertical axial grooves 116 each of which extends radially inward relative to the surface of the convex cylindrical side wall 94 .

The profile of the bottom wall 118 of each axial groove 116 is here common to the convex cylindrical profile of the bottom wall 108 of the radial groove 106. Each axial groove 116 opens axially downwards into the annular radial face of the axial end lower 104.

The number, dimensions and angular distribution of the axial grooves 116 is identical and complementary to those of the axial ribs 82 of the lower base 22.

Thus, as can be seen in particular in the figure 9 , in the assembled position in which the side wall 94 of the upper actuating rod 24 is received and guided in axial sliding in the guide bore 80, each axial rib 82 is received in axial sliding in a complementary axial groove 116 of the upper actuating rod 24.

The return spring 28 is here a helical compression spring, also called coil spring, whose circular cylindrical body is crossed by the upper actuating rod 24.

The upper end turn 120 is here generally circular in shape and it bears axially against the lower annular radial face 102 of the radial plate 96.

The turn 122 of the lower end, also called the last turn of the return spring 28, is here generally triangular in shape and it bears axially against the radial face 114 oriented axially upwards from the lower radial shoulder 112.

Thus, as can be seen, for example, in figure 6 , when assembling the spring on the actuating rod, the return spring is mounted slightly compressed axially without play between the opposite radial faces 102 and 114.

In this initial state of the return spring 24, and as can also be seen in figures 2 and 3 , the last turn 122 is arranged in the housing of the side wall 94 of the upper actuating rod 24 which constitutes the radial groove 106.

The average internal diameter of the last turn is reduced compared to the internal diameter of the other turns so as to be adjacent to the convex cylindrical side wall of the radial groove 106. Thus, the turn 122 is in axial support on the facets 84 and the tactile sensation during actuation is optimized.

In the high rest position of the upper actuating rod 24, the last turn 122 bears axially downwards against the radial face 49 of the lower base 22 and the spring 24 exerts an elastic return force, towards the top, of the upper actuating rod 24, this high rest position being determined by the axial support upwards of the hooks 66 against the upper bottom 61 of the axial grooves 60.

As can be seen in detail at figure 9 , different sections of the last turn 122 of the return spring 28 bear axially against an abutment facet 84 of an axial rib 82, or extend facing an abutment facet 84 of an axial rib 82.

Thus, when the switch is actuated and the upper actuating rod 24 is depressed axially downwards against the elastic return force which is applied to it by the spring 28, the last turn 122 bears axially on the facets 84 without risk of jamming of this turn 122 between the upper actuating rod 24 and the lower base 22, including when the last turn 122 cooperates with the cam profile formed by the frustoconical ramp 110.

Second example of realization

In the second exemplary embodiment shown in figure 10 , the last turn 122 is generally circular.

Claims (6)

1. Electrical switch (20) with axial actuation comprising:

   - a lower base (22);

   - an upper actuating rod (24) comprising a section whose cylindrical side wall (94) is guided axially sliding in a guide bore (80) formed in the lower base (22);

   - a elastic member (28) for returning the upper actuating rod (24) to a high rest position,

   wherein, under the action of an actuating force applied to the upper actuating rod (24) and against the force exerted by the elastic return member (28), the upper actuating rod (24) is displaced axially with respect to the lower base (22), along an actuating travel, towards an active lower position for changing the state of at least one electrical switching way (32, 34),

   and comprising an elastic ring (122):

   -- which is arranged in a peripheral housing (106) formed in said side wall (94)

   -- which is axially traversed by said section of the upper actuating rod (24)

   -- which, during the actuation travel of the upper actuation rod (24), is in axially downward abutment against a fixed stop surface belonging to the lower base (22);

   -- and which, during the actuation travel of the upper actuation rod (24), cooperates with a cam profile (110) formed in said side wall (94) which deforms it radially in order to produce an elastic resistance to the actuation of the upper actuation rod (24)

   characterised in that:

   - the guide bore (80) comprises a series of axial ribs (82) each of which projects radially inwardly of the guide bore (80) and is slidably received in a complementary axial groove (116) formed in said side wall (94); and

   - said fixed abutment surface is constituted by the radial upper end facets (84) of each axial rib (82).
2. Switch according to the preceding claim, characterised in that said housing (106) is delimited axially downwards by a lower radial shoulder (112) and upwards by said cam profile (110).
3. Switch according to the preceding claim, characterised in that said cam profile (110) is a cone section whose apex is oriented axially downwards forming a ramp with which the elastic ring (122) cooperates.
4. A switch according to any one of claims 2 or 3, characterised in that each axial groove (116) formed in said side wall (94) extends axially upwardly beyond said cam profile (110).
5. Electrical switch according to any one of the preceding claims, characterised in that the said elastic return member (28) is a helical compression spring through which the said section of the upper actuating rod (24) passes axially, the lower turn (122) of which constitutes the said elastic ring.
6. An electrical switch according to the preceding claim taken in combination with any one of claims 2 to 4, characterised in that said spring (28) is mounted axially compressed between the upper radial end facets (84) of each axial rib (82) and an upper radial shoulder (102) which axially delimits said section upwards

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