EP0074315B1 - Hermetically sealed, modular, tactile keyboard - Google Patents

Description

The subject of the invention is a waterproof modular keyboard with a tactile effect.

It is particularly applicable to short stroke keyboards for numerically controlled machines, programmable logic controllers, typewriters and word processors.

It is known, to produce thin waterproof keyboards and at low cost, to deposit by screen printing a conductive ink on one side of a plastic sheet, the other side of which contains the inscriptions corresponding to the characters, to start depositing again. conductive ink on one side of another flexible plastic sheet, to join the two sheets together so that the two sides covered with conductive ink meet face to face, separated by a thin film of air of a few tenths of a millimeter. In this way, a thin, waterproof keyboard is obtained, which can be easily cleaned, but whose reliability is unacceptable for use on industrial products.

In addition, this type of keyboard has the major drawback of not having a stroke allowing the operator to realize without display means, by simple tactile sensation, if his action has been taken into account by the machine connected to the keyboard.

There are also reliable and robust keyboards of the typewriter type with mobile keys having large strokes of the order of 4 mm and making it possible to realize without means of visualization, by simple tactile sensation, that the key has been pressed. (e.g. US-A-3,829,646 and 3,749,859). However, these keyboards, because of their large stroke, are not waterproof and easy to maintain.

The invention combines the advantages of these different keyboards, while eliminating their respective drawbacks.

The invention enables a reliable, waterproof, easy-to-maintain, robust, modular keyboard to be produced at low cost.

According to the invention, a keypad intended to be mounted in the housing of an apparatus and comprising: a printed circuit board serving as support and connection means for a plurality of modular switches housed in housings, placed side by side side by side and each actuated by a push-button to receive and transmit the movements of a cooperating key, deformable means being associated with each push-button-switch assembly to communicate a tactile sensation to the user, an insulating, rigid spacer of generally planar shape, fixed to said card and forming a plurality of through cells housing the respective housings, is characterized in that the walls of said cells have outer edges and an internal surface substantially perpendicular to said card and having retaining means; that said deformable means comprise a membrane which covers the cells and is fixed to said outer edges, the portion of membrane which closes each cell being provided with an opening; and by the fact that each push-button assembly comprises an outer part and an inner part to the corresponding cell, connected together by a part which passes through the opening and is fixed to the membrane, said inner part having a surface portion peripheral shaped to slide along said internal surface and provided with abutment means cooperating with said retaining means.

• - une carte de circuit imprimé;
• - une entretoise moulée comprenant au moins un alvéole présentant au moins une ouverture supérieure;
• - au moins un interrupteur logé dans ledit alvéole et raccordé audit circuit imprimé à l'aide de moyens de raccordement;
• -au moins un ensemble touche-poussoir monté coulissant dans ledit alvéole de manière à actionner ledit interrupteur; et
• - des moyens déformables associés audit ensemble touche-poussoir-interrupteur pour communiquer une sensation tactile à l'utilisateur.

According to another characteristic of the invention, the key keyboard comprises:

• - a printed circuit board;
• - a molded spacer comprising at least one cell having at least one upper opening;
• - at least one switch housed in said cell and connected to said printed circuit by means of connection means;
• at least one push-button assembly mounted to slide in said cell so as to actuate said switch; and
• - deformable means associated with said push-button-switch assembly to communicate a tactile sensation to the user.

• - les moyens déformables consistent en une membrane en matériau élastique formant un bossage dont la base supérieure est solidaire d'une partie de l'ensemble touche-poussoir extérieure à l'alvéole;
• - ledit alvéole présente une surface interne dont au moins une partie est perpendiculaire à ladite carte et comprend par ailleurs autour de ladite ouverture, des bords extérieurs munis de moyens de fixation qui coopèrent avec des moyens de fixation correspondants prévus le long de la base inférieure de ladite membrane;
• - l'ensemble touche-poussoir comprend une partie intérieure à l'alvéole, agencée de manière à actionner ledit interrupteur et possédant au moins une surface de guidage périphérique coopérant avec ladite partie de surface interne de l'alvéole pour assurer un guidage axial de l'ensemble touche-poussoir.

It is more particularly characterized in that:

• - The deformable means consist of a membrane of elastic material forming a boss, the upper base of which is integral with a part of the push-button assembly external to the cell;
• - Said cell has an internal surface at least part of which is perpendicular to said card and further comprises around said opening, external edges provided with fixing means which cooperate with corresponding fixing means provided along the lower base of said membrane;
• - The push-button assembly comprises an interior part of the cell, arranged so as to actuate said switch and having at least one peripheral guide surface cooperating with said part of the internal surface of the cell to ensure axial guidance of the '' push button assembly.

Other features and advantages of the invention will become apparent in the light of the detailed description below.

• La fig. 1 est une vue de dessus d'un clavier reposant par l'intermédiaire d'une membrane sur une entretoise modulaire associée;
• La fig. 2 est une vue en coupe d'un mode de réalisation du clavier;
• La fig. 3 est une vue en coupe d'un module de contact;
• La fig. 4 est une vue de dessus du module de contact;
• La fig. 5 est une vue en coupe d'une touche double;
• La fig. 6 est une vue en coupe d'une touche simple utilisant un autre mode de réalisation d'une membrane modulaire et étanche;
• La fig. 7 est une vue de dessus d'une touche avec voyant;
• La fig. 8 est une vue en coupe diagonale de la même touche avec voyant;
• La fig. 9 est une vue en coupe d'un voyant fixe;
• La fig. 10 est une vue en perspective de la membrane d'étanchéité;
• La fig. 11 est une vue en perspective d'un premier mode de montage de la touche sur la membrane;
• La fig. 12 est une vue en perspective d'un deuxième mode de montage de la touche; et
• La fig. 13 est une vue en coupe d'un deuxième mode de réalisation de la membrane utilisée avec le deuxième mode de montage de la touche.

In the accompanying drawings:

• Fig. 1 is a top view of a keyboard resting by means of a membrane on an associated modular spacer;
• Fig. 2 is a sectional view of an embodiment of the keyboard;
• Fig. 3 is a sectional view of a contact module;
• Fig. 4 is a top view of the contact module;
• Fig. 5 is a sectional view of a double button;
• Fig. 6 is a sectional view of a simple button using another embodiment of a modular and waterproof membrane;
• Fig. 7 is a top view of a button with indicator light;
• Fig. 8 is a diagonal sectional view of the same button with indicator;
• Fig. 9 is a sectional view of a fixed indicator;
• Fig. 10 is a perspective view of the sealing membrane;
• Fig. 11 is a perspective view of a first method of mounting the button on the membrane;
• Fig. 12 is a perspective view of a second method of mounting the button; and
• Fig. 13 is a sectional view of a second embodiment of the membrane used with the second method of mounting the button.

Fig. 1 represents a set of keys 8 resting on a membrane 1 partially removed to reveal a spacer 3 on which the key-membrane assembly rests. This modular honeycomb spacer 3 obtained by molding comprises a plurality of cells 30 arranged in rows and columns. This plurality of housings or cells of square shape are defined by partition walls 31 having precuts 32 so as to modify the dimension of a cell and to obtain cells having several modules of length. In these housings or cells, contact modules or indicator modules are available depending on the type of keyboard that one wishes to achieve and, in cooperation with these contact modules, keys in square shape comprising the alphanumeric characters or other signs corresponding to the keyboard that we want to achieve. Depending on the type of keyboard that one wishes to achieve, all or part of the modular honeycomb spacer is used.

As will be explained below, the use of this spacer in combination with the modular elements constituting a keyboard makes it possible to obtain keyboards that are easily adaptable to demand.

Fig. 2 shows an embodiment of a waterproof modular keyboard with tactile effect and a relatively large stroke, in which there has been mounted on a support constituted by a printed circuit 4, contact modules 7 at the locations corresponding to the housings of a spacer modular 3 which is fixed on the printed circuit by means of screws 22 for example. The modular spacer 3 can also be fixed to the printed circuit by crimping or any other fixing means. This modular spacer 3 comprises partitions 31 separating the housings from the precuts 32 to detach several partitions and obtain housings with dimensions adapted to the keys and, in addition, housing covers 33 connected to the partitions delimiting the housing, by a thin web 34 allowing by pressing on the cover, detach the cover from the grid and obtain an opening at the location chosen to place a button 30. The partitions of the grid have a flat lower face in contact with the printed circuit, an upper face in which is formed a longitudinal groove 35 and two lateral faces each comprising a vertical portion 36 and an inclined portion 37 forming with the vertical portion 36 a shoulder 38.

The face of the covers, outside the housings, is in a plane parallel to the plane in which the upper faces of the partitions are situated.

A membrane 1 made of polyurethane or any other elastic and waterproof material that can be easily molded has bosses 100 in the form of a trunk of pyramid 105 with a square base, the upper base of which cooperates with a key or rests on the upper face of the associated cover in the case where there is no key, and whose lower base is secured to the spacer by longitudinal and transverse ribs 101 which are fixed in the grooves 35 of the spacer 3 by gluing, crimping, welding or any other suitable means .

The upper base of the membrane boss has a bead 102 sealing with the button 8 which is mounted on this upper base after having made a cruciform notch 107 in the membrane, as shown in FIGS. 10 and 11, to allow the passage of the latching head 84 of the button 8 with the assembly part 11, comprising a flange 110 which limits the movement of the part 11 coming into abutment against the shoulder 38. The flange also cooperates with the faces vertical 36 of the partitions closing the housing to form a means for guiding the button when the latter moves vertically.

Thus, by removing the covers of the housings where one wishes to put keys and by mounting the keys which one desires in the desired locations one obtains a waterproof keyboard which from modular elements can have the arrangement and the number of keys that we want.

The seal between the keyboard and the housing 12 of the device using the keyboard is ensured by tightening the membrane against the housing 12, for example by means of a device such as that shown in FIG. 2 comprising a nut 122 welded to the housing, a flange 120 and a screw 121.

Figs 3 and 4 show a contact module used in the keyboard of fig. 2, comprising a polycarbonate housing 74 of circular shape provided with two holes in the bottom of the housing to allow passage to two pins 77, 78 of conductive material, provided with contact heads. The bottom of the housing also includes two bosses 70, 71 fig. 4. A contact blade 75, constituted by a thin sheet of conductive material, comes to rest in the housing bearing on the bosses 70, 71 and the pin 77 so that at rest the electrical connection between the pins 77 and 78 does not is not established, while in the working position it will be established. A thin waterproof polycarbonate film constituting a membrane 76 is bonded or welded to the housing 74.

This type of contact module has the advantage of not having a tactile effect due to the passage of a hard point. This contact module therefore avoids to superimpose a tactile effect due to the module, to the tactile effect of the boss 105 of FIG. 2.

The housing 74 has on its periphery a circular rib 79.

In operation, when a key is pressed, the sides of the boss compress until the membrane suddenly takes the shape of the reverse pyramid as shown in FIG. 4, thus creating a tactile effect. In this second position, the key presses on the contact dome and establishes the electrical connection between the pins 77 and 78. As soon as the key is released, the membrane returns to its initial shape. In places where there is no key, the cover 33 supports the boss of the membrane and prevents the membrane from being pushed in. A keyboard is thus obtained allowing the operator to feel the operations carried out by touch.

Fig. 5 shows the production and mounting of a multiple key, for example double. For this, a double key 81 of length equal to twice the length of a single key plus the distance separating two adjacent keys is produced. This double key has two latching heads 84 which are mounted by means of two assembly parts 11 on the membrane secured to the grid 3 from which an intermediate partition has been removed at the place where the key is to be mounted. double.

Fig. 6 shows a variant of the second method of mounting a unitary button with label housing. The partitions 31 of the spacer 3 do not have a shoulder 38 but have on their vertical parts 36 an extension 360 constituting a circular opening in which a contact module is fixed by snap-fastening of the rib 79 with a corresponding groove 361. The connecting piece 11 does not have a collar, but a guide surface 112 and is assembled by snap-fastening with the button 8 label holder, constituted in a manner known per se by a body 85 comprising in a housing 88 a label protector 86 in transparent material and a label 87.

The body 85 of the key and the connecting part 11 after assembly, tighten, so as to seal between the key and the membrane, a bead 102 formed at the periphery of an opening obtained in the membrane in the way represented in figs 12 and 13. A tongue 104 makes it possible to remove a piece of membrane precut according to the precut 103 of square shape and to obtain an opening 106 which allows the mounting of a key as represented in fig. 6.

Fig. 7 shows a top view of a square shaped button having in a corner of the button a transparent circular window 83 for an indicator and a label protector 86 of circular shape adapted to the shape of the finger.

Fig. 8 shows a diagonal sectional view of the button with indicator mounted on the keyboard in a housing comprising in addition to the contact module 7 a support 51 for light-emitting diode 6 mounted in an opening 41 formed in the printed circuit. The assembly piece 11 mounted in the housing includes a skylight 111 opposite the diode and the transparent window provided on the button.

Fig. 9 shows the mounting of a fixed indicator in an opening provided for a key in which a support 51 for light-emitting diode 6 has been mounted on the printed circuit. A cabochon made of transparent material 23 of shape suitable for cutting the membrane and comprising on its lateral faces 25 a groove 24 in which the bead 102 of the membrane is clamped by an internal collar 114 provided on the assembly part which just snaps onto the cap. An outer flange 113 and the lateral faces 25 prevent any movement of the cap relative to the grid. Thus, thanks to these different modular elements, grids and membranes which have predetermined dimensions, it will be possible to produce watertight keyboards, with or without sight glass, and suitable for all types of application. It is obvious that in these different embodiments it will be possible to stiffen the structure by mounting an angle 13 on the printed circuit.

Claims (12)

1. A keyboard adapted to be fitted with an apparatus casing and comprising: a printed circuit card serving itself as a support and as a connection means for a plurality of modular switches (7) accomodated in housings (74) disposed in a side-to- side relationship and each adapted to be actuated by a push button which receives and transmits the movements of a key (8) cooperating therewith, deformable means being associated to each key-push button -switch assembly to impart a tactile feeling to the user, an insulating, rigid, generally planar spacer (3) fixed to said card (4) and forming a plurality of passing through alveoles (30) acco- modating the respective housings (74), characterized in that the walls of said alveoles (30) have outer edges and an internal surface (36) substantially perpendicular to said card and having means (38) for retaining the key (8); in that said deformable means comprise a diaphragm (1) which covers the alveoles and is fixed to said outer edges, the part of-the diaphragm which closes each alveole being provided with an opening (107); and in that each key-push button assembly comprises an outer portion (8) and an inner portion (11) with respect to the corresponding alveole, connected together by a portion (84) which passes through the opening and is fixed to the diaphragm, said inner portion having a peripheral surface portion adapted for sliding along said internal surface and provided with abutment means (110) cooperating with said retaining means (38).

2. A keyboard according to claim 1, characterized in that bosses having a truncated pyramidal shape (105) are provided on said deformable diaphragm (1), said bosses having their lower base secured to said planar spacer (3) and their movable upper base supporting the outer part of the keys (8, Fig. 2), said bosses being associated to means (84-11-102) for sealingly fitting the keys.

3. A keyboard according to claim 2, characterized in that said means for sealingly fitting the keys comprise a bead (102) which is secured to said deformable diaphragm (1) and is clamped between a supporting surface of the outer portion of the key and a supporting surface of the inner portion (11) which is snap-fastened to the outer portion (84).

4. A keyboard according to claim 3, characterized in that the key comprises a circular housing (88), a label (87) accomodated in said housing and covered with a label cover (86) fitting into said housing.

5. A keyboard according to claim 4, characterized in that the key is substantially square shaped and includes in a corner thereof a port-hole (83) for a sight.

6. A keyboard according to claim 1, characterized in that the bottom of the casing of each modular switch is provided with a pair of bosses (70, 71) and a pair of contact pins (77, 78) extends through said casing bottom, a metal contact strip (75) being in supporting relationship on said bosses (70, 71) and a further diaphragm (76) covering said casing.

7. A keyboard according to claim 6, characterized in that the outer surface of said casing is provided with a circularly extending rib (79, Fig. 3) cooperating with a groove (361, Fig. 6) which is provided on side surfaces (36) of the housing walls.

8. A keyboard according to claim 2, characterized in that the said deformable diaphragm (1) has pre-cut openings therein having the same shape and substantially the same dimensions as said keys.

9. A keyboard according to claim 8, characterized in that a sight cap (23) is fitted in a diaphragm opening (106).

10. A keyboard according to claim 1, characterized in that said keyboard is sealingly fitted in the casing of an apparatus to be used therewith by tightening of said deformable diaphragm (1) against the inner side of the outer wall of said apparatus casing (Fig. 2).

11. A keyboard of the type comprising:

- a printed circuit card;

- a moulded spacer comprising at least one alveole having at least an upper opening;

- at least a switch housed in said alveole and connected to said printed circuit by connecting means;

- at least a key-push button unit slidably mounted in said alveole so as to actuate said switch; and

- deformable means associated with said key-push button-switch unit so as to communicate to the user a tactile feeling,

characterized in that:

-the deformable means consist of a membrane (1) made of resilient material forming a boss (100), the upper base of which is integral with a part of the key-push-button unit which is not contained in the alveole;

- said alveole has an internal surface at least one part of which is perpendicular to said card and further comprises, around said opening, outer edges provided with fixing means (35) cooperating with the corresponding fixing means (101) provided along the lower base of said membrane (1);

- the key-push button unit (8, 11) comprises a part housed in the alveole, adapted to actuate said switch and having at least one peripheral guiding surface (112) cooperating with said part of the inner surface of the alveole so as to provide axial guiding of the key-push button unit.

12. Keyboard according to claim 11, characterized in that said membrane comprises an opening and in that the outer and the inner parts of the key-push button unit are connected together by a part passing through said opening.

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