FR3107778A1 - SWITCH - Google Patents

Abstract

The invention relates to a switch comprising: - a body (1) comprising a printed circuit (4), - an actuator (2) movable in pivoting about an axis (12) of the body, - a return spring (3) configured to urge the actuator (2) in rotation towards a rest position, - a magnet (26) rigidly secured to the actuator (2), - a rotary sensor arranged on the printed circuit (4) facing the magnet (26), configured to detect the angular position of the magnet, said switch being characterized in that it comprises an indexing device for the actuator (2) comprising a metal cam (5) integral with the body (1 ) and a ball (51) adapted to circulate along the cam (5), the cam (5) being provided with cavities (50) able to temporarily receive the ball, said ball being biased by a spring (52) s' extending radially from the actuator (2), and in that the cam (5) has at each end a fork with two teeth (53), the cam (5) being ada ptée to be crimped on the body (1) by deformation of said teeth (53). Figure for the abstract: [Fig 7A]

Description

SWITCH

FIELD OF THE INVENTION

The present invention relates to a switch, of the rocker switch (“rocker” according to the English terminology) or wheel (“roller” according to the English terminology) switch type.

STATE OF THE ART

Rocker or thumbwheel switches lend themselves to a large number of applications for controlling different machines.

However, there are still improvements to be made in terms of the assembly precision of the various components, which may impact the operating performance of the switch.

In addition, depending on the applications, it may be interesting to integrate different functionalities into the switch.

However, the number of different versions of the same switch is often accompanied by the multiplication of the constituent components of the switch, which complicates inventory management and increases the cost price of the switch.

An object of the invention is to remedy the aforementioned problems.

According to a first aspect, the invention aims to design a switch with higher performance than in the state of the art.

According to a second aspect, whether or not combined with the first, the invention aims to design a switch which can integrate different functionalities without modifying the definition of the main components of the switch.

The invention proposes a switch comprising:

- a body comprising a printed circuit,

- a mobile actuator pivoting around an axis of the body,

- a return spring configured to urge the actuator to rotate towards a rest position,

- a magnet rigidly attached to the actuator,

- a rotary sensor arranged on the printed circuit opposite the magnet, configured to detect the angular position of the magnet,

said switch being characterized in that it comprises a device for indexing the actuator comprising a metal cam integral with the body and a ball adapted to circulate along the cam, the cam being provided with cavities capable of temporarily receiving the ball , said ball being biased by a spring extending radially from the actuator.

According to one embodiment, the return spring is a torsion spring comprising two rectilinear and parallel end strands arranged on either side of pads respectively integral with the body and the actuator, said pads having an identical width and being aligned in the rest position such that, in the rest position, each of the strands of the return spring is in contact with a respective side of each of said studs, the width of the studs and the length of the strands being chosen to ensure zero play between the studs and the strands in the rest position.

According to one embodiment, the ball is metallic.

According to a particularly advantageous embodiment, the cavities of the cam pass through and the body comprises one or more openings facing said cavities.

According to one embodiment, the cam has at each end a fork with two teeth, the cam being adapted to be crimped onto the body by deformation of said teeth.

According to one embodiment, the cam rests on a seat of the body having a curvature identical to that of the cam.

According to one embodiment, the printed circuit has a through orifice and is held in the body by a positioning pin extending through said orifice and an orifice arranged in the body.

According to one embodiment, in which the actuator is formed of a translucent material covered with a layer of opaque paint, having a pattern selectively formed in the layer of paint so as to expose the translucent material, and the printed circuit supports at at least one light-emitting diode arranged opposite the actuator so as to provide backlighting of said pattern.

According to one embodiment, the switch further comprises a cover rigidly secured to the actuator, the magnet being molded into said cover.

BRIEF DESCRIPTION OF FIGURES

Other characteristics and advantages of the invention will emerge from the detailed description which follows, with reference to the appended drawings in which:

- there is an exploded view of a switch according to one embodiment,

- there is a perspective view of the switch cover of the ,

- there is a perspective view of the switch actuator of the ,

- there is a sectional view of the switch from the in the assembled state,

- there is a sectional view of the switch showing the operation of the return spring,

- there is a sectional view of the switch showing the ball indexing principle,

- Figures 7A and 7B are perspective views of the switch respectively during and after assembly of the printed circuit.

Identical reference signs from one figure to another designate elements that are identical or fulfill the same function.

DETAILED DESCRIPTION OF EMBODIMENTS

Generally speaking, the switch comprises a body which supports the various components. In particular, the body comprises an axis on which an actuator is pivotally mounted. The actuator is adapted to be pivoted by an operator to activate the switch. The pivoting of the actuator is detected by a sensor arranged on a printed circuit which produces an output signal. A return spring is arranged between the body and the actuator to return the actuator to a rest position.

The switch can be rocker or thumbwheel. In the case of a thumbwheel switch, the angular displacement of the actuator is typically ± 30°; in the case of a rocker switch, the angular displacement is typically ± 15°.

As will be described in detail below, the return spring is advantageously designed to minimize the play between the body and the actuator when the product is released, guaranteeing better positioning over time.

According to one embodiment, the switch may further comprise an actuator indexing device. This indexing device, which comprises a cam and a ball circulating on the cam by drive by the actuator, defines one or more preferred angular positions of the actuator.

According to one embodiment, the switch may comprise a device for fixing the printed circuit in the body, which provides precise and constant positioning of the printed circuit with respect to the body.

According to one embodiment, the actuator may comprise a pattern backlit by means of light-emitting diodes arranged in the body.

There is an exploded view of a switch according to one embodiment of the invention, and the is a sectional view of said switch in the assembled state. The illustrated switch integrates all the aforementioned embodiments, but it goes without saying that it could only include some of these functionalities, depending on the intended application. Each feature can therefore be considered independently of the others and does not affect the design of the other components of the switch.

The body 1 comprises a shaft 12 on which the actuator is intended to be pivotally mounted. The axis 12 comprises a cylindrical external surface of revolution, adapted to receive a return spring 3 of the actuator, and a cylindrical internal surface also having a geometry of revolution, adapted to receive a cylindrical axis of the actuator. The return spring tends to return the actuator to a rest position of the switch. The restoring force must be overcome by the operator to activate the switch.

The return spring 3 is a torsion spring having at least two circular coils and two straight and parallel end strands 30, 31. In view in a plane perpendicular to the winding axis of the turns, the strands are separated from each other by a controlled distance. As will be seen below with reference to the , this spacing D, which is controlled over a length L of the strands 30, 31 which is increased compared to known switches, makes it possible to control the clearance at the level of the rest position.

The actuator 2 is mounted on one side of the shaft 12 of the body and is closed by a cover 22 arranged on the other side of the shaft 12. The actuator 2 and the cover 22 therefore form a rigid assembly which defines an interior volume surrounding a part of the body 1, the return spring 3 and the electronic components of the switch. This set includes an axis adapted to be received in the axis 12 of the body; the part of said axis extending from the cover is designated on the by reference 23; although not visible in Figures 1 or 3, the actuator also includes a shaft portion adapted to be received in shaft 12.

Said electronic components are mounted on a printed circuit 4; their nature and function depend on the application of the switch and will not be described in detail in this text.

The printed circuit 4 is arranged in a housing of the body 1, to which it is rigidly attached, for example by means of glue 14. Electric wires 40 extend from the printed circuit outside the body 1 to allow its connection to a machine.

The analog output of the switch is produced by a rotary Hall effect sensor associated with a cylindrical magnet. The rotary sensor 41 is mounted on the printed circuit 4 and is therefore fixed to the body 1, while the magnet 26 is fixed to the cover 22 and therefore to the actuator 2. The sensor makes it possible to detect a rotation of the magnet 26 generated by an action exerted on the actuator.

The actuator 2 has on its outer surface a gripping zone 21 for manipulation by an operator. Advantageously, the gripping zone is materialized by a boss which allows easier gripping by a finger of the operator. Naturally, the gripping zone could have any other shape or surface finish.

As seen best on the , the magnet 26 is a cylindrical magnet whose poles each extend along the axis of the cylinder, on either side of a plane which contains said axis. Magnet 26 is integral with cover 22, the axis of the cylinder being coaxial with the axis of rotation of the actuator-cover assembly. The attachment of the magnet vis-à-vis the cover can be achieved by overmolding, gluing, or any other appropriate means.

When the switch is assembled, the distance between the face of the magnet opposite the sensor and the sensor is of the order of 1 mm to a few mm.

The cover 22 also has one or more fixing lugs 24 (three in number in the illustrated embodiment) configured to snap onto clips 25 arranged in the actuator. Naturally, this method of assembly is only given by way of illustration and the person skilled in the art could choose any other means of securing the cover to the actuator, for example by snap-fastening, gluing, welding, screwing, etc.

The angular positioning of the actuator relative to the cover is ensured by two studs 29 of the cover 22 cooperating with complementary shapes of the actuator.

The cover 22 also has, in the vicinity of its circumference, a stud 28 intended to be interposed between the two end strands 30, 31 of the return spring 3. The width of the stud is equal to the distance D between the two strands 30 , 31 at rest.

According to one embodiment, the switch comprises one or more light-emitting diodes (LEDs) providing backlighting of the actuator. The actuator is decorated with a pattern 20 (logo, text or other marking) at least partially transparent to the light emitted by the LEDs. For example, the actuator can be made of a translucent material, covered with a layer of opaque paint on its outer surface, then the pattern 20 is engraved by laser in order to locally remove the paint and expose the translucent material.

The light-emitting diodes 13 are arranged on the printed circuit 4. A translucent encapsulation material 17, such as silicone, is arranged between the body and the part of the printed circuit comprising said diodes.

The body, the actuator and the cover are advantageously manufactured by injection of a plastic material.

There is a sectional view of the switch along a first plane perpendicular to the pivot axis of the actuator, the spring extending in this first plane.

The return spring 3 is arranged around the pivot axis 12 of the actuator, and is held in position on the body 1 by a stud 10 of the body and on the cover by the stud 28 described above.

Stud 10 has the same width D as stud 28, which corresponds to the distance between strands 30, 31 at rest.

In the rest position of the switch, which is that shown on the , the pads 10 and 28 are aligned.

Strands 30 and 31 of return spring 3 are arranged on either side of these two studs. The width D of the studs 30, 31 being equal to the distance between the strands 30, 31, each strand is in contact with a respective side of each of these two studs.

Compared to the switches of the state of the art, the width D of the pads and the length L of the strands have been chosen to ensure that there is no play of the spring vis-à-vis the pads in the rest position, and consequently more precise centering of the actuator with respect to the body.

In particular, the choice of these two dimensions results from a compromise in the design of the switch.

Regarding the length L of the strands, it has been increased compared to the springs used conventionally. Indeed, the spring manufacturing process suffers from large dispersions in terms of orientation of the strands relative to the turns and parallelism of the strands between them when the strands are relatively short. Extending the length of the strands makes it possible to control much more precisely the orientation of the strands and their parallelism. On the other hand, the elongation of the strands involves providing sufficient space in the body and the actuator to accommodate said strands.

With regard to the width D of the studs, it is optimized between a threshold value below which play with the spring will be difficult to avoid (the studs not being wide enough to apply a preload between the two strands of the spring ) and a ceiling value above which the angle of movement of the actuator becomes too low compared to the specifications.

When a force is applied to the gripping zone 21 of the actuator, the actuator and the cover are driven together in rotation, which has the effect of causing the stud 28 to pivot with respect to the stud 10 against the biasing of the return spring 3, thus driving one of the strands of the return spring. When the force exerted on the gripping area is released, the return spring 3 tends to bring the stud 28 back into its position of alignment with respect to the stud 10.

There is a sectional view of the switch along a second plane perpendicular to the pivot axis of the actuator, illustrating one embodiment of an actuator indexing device.

The actuator 2 is provided with a blind housing 27 open outwards, in which is arranged a compression spring 52 which urges a ball 51 radially outwards.

The ball 51 is adapted to circulate along a cam 5 whose profile is in the form of an arc of a circle parallel to the circumference of the actuator. The cam 5 advantageously rests on a seat 15 formed on the body with a curvature identical to that of the cam, which has the effect of stiffening the cam during the circulation of the ball.

The cam 5 is provided with one or more cavities 50 of diameter slightly smaller than the diameter of the ball, each cavity being capable of temporarily retaining the ball under the effect of the pressure exerted by the spring 52. The various cavities 50 therefore define as many indexed positions of the actuator. The force of the spring can be overcome by the exertion of a force on the gripping zone of the actuator by an operator, which makes it possible to move the actuator from one indexed position to another.

Advantageously, the cavities 50 of the cam pass through and are arranged facing respective openings 16 provided in the seat 15. Thus, any dust present in the body does not accumulate in the cavities (which could obstruct them and degrade the indexing function), but are evacuated through the openings 16.

Particularly advantageously, the ball 51 and the cam 5 are metallic, so that they have very good resistance to wear.

The cam 5 can be manufactured very easily, by cutting out a metal sheet, drilling cavities 50 and bending to give it the desired radius of curvature.

In a particularly advantageous manner, the cam 5 has at each of its ends a fork formed of two teeth 53. After assembly of the cam on the body, the teeth 53 can be deformed by a suitable tool, so that the cam 5 is crimped on the body in a non-reversible way.

A particular advantage of this indexing device is that it can be integrated into the switch or not, depending on the customer's need, without affecting the design and manufacture of the rest of the switch. In fact, the integration of the indexing device simply involves assembling the cam 5 on the body, the spring 52 in the housing 27 of the actuator and the positioning of the ball 51 between the spring 52 and the cam 5.

Figures 7A and 7B represent an embodiment of the switch in which the printed circuit is positioned in the body using a fixing pin. Compared to switches of the state of the art, in which the printed circuit is simply inserted and glued into the body, the present embodiment makes it possible to ensure precise positioning of the printed circuit with respect to the body, which makes it possible to ensure proper centering of the sensor relative to the cylindrical magnet.

To this end, the printed circuit 4 is provided with a through hole 42, and the body 1 also has a through hole 11 intended to be coaxial with the hole 42 of the printed circuit when the latter is inserted into the body. Advantageously, for reasons of space, the orifice 11 is located near the passage of the wires 40.

A pin 43 is inserted through holes 11 and 42.

Advantageously, the pin 43 comprises a rod and a head whose diameter is greater than that of the rod. The orifice 11 then advantageously comprises an inlet portion whose diameter is large enough to receive the head of the pin, and a passage portion of smaller diameter adapted to the passage of the rod of the pin. Thus, as seen in the , the pin does not protrude from the body once the rod has been inserted through the printed circuit.

The pin can be made of a thermoplastic material.

After positioning the pin, glue can be injected into the housing in order to block the printed circuit and the pin 43 in the position thus defined.

Claims (8)

Switch including:
- a body (1) comprising a printed circuit (4),
- an actuator (2) movable in pivoting around an axis (12) of the body,
- a return spring (3) configured to urge the actuator (2) in rotation towards a rest position,
- a magnet (26) rigidly secured to the actuator (2),
- a rotary sensor (41) arranged on the printed circuit (4) facing the magnet (26), configured to detect the angular position of the magnet,
said switch being characterized in that it comprises a device for indexing the actuator (2) comprising a metal cam (5) integral with the body (1) and a ball (51) adapted to circulate along the cam ( 5), the cam (5) being provided with cavities (50) capable of temporarily receiving the ball, said ball being biased by a spring (52) extending radially from the actuator (2), and in that the cam (5) has at each end a fork with two teeth (53), the cam (5) being adapted to be crimped onto the body (1) by deformation of said teeth (53). Switch according to Claim 1, in which the return spring (3) is a torsion spring comprising two rectilinear and parallel end strands (30, 31) arranged on either side of studs (10, 28) respectively of the body (1) and of the actuator (2), said studs (10, 28) having an identical width (D) and being aligned in the rest position such that, in the rest position, each of the strands (30, 31) of the return spring is in contact with a respective side of each of said studs (10, 28), the width (D) of the studs (10, 28) and the length (L) of the strands (30, 31 ) being chosen to ensure zero play between the studs (10, 28) and the strands (30, 31) in the rest position. Switch according to one of Claims 1 or 2, in which the ball (51) is metallic. Switch according to one of Claims 1 to 3, in which the cavities (50) of the cam pass through and the body (1) comprises one or more openings (16) facing the said cavities (50). Switch according to one of Claims 1 to 4, in which the cam (5) bears on a seat (15) of the body having a curvature identical to that of the cam. Switch according to one of Claims 1 to 5, in which the printed circuit (4) has a through hole (42) and is held in the body (1) by a positioning pin (43) extending through the said hole (42) and an orifice (11) arranged in the body (1). Switch according to one of Claims 1 to 6, in which the actuator (2) is formed of a translucent material covered with a layer of opaque paint, presenting a pattern (20) selectively formed in the layer of paint so to expose the translucent material, and the printed circuit (4) supports at least one light-emitting diode (13) arranged opposite the actuator (2) so as to provide backlighting of said pattern. Switch according to one of claims 1 to 7, further comprising a cover (22) rigidly secured to the actuator (2), the magnet (26) being molded into said cover (22).