EP0671752B1 - Keyboard - Google Patents

Description

The invention relates to a keyboard with inserted safety mats and Switching foils, and in particular such a keyboard with one on the Underside provided measure to increase the bending and Torsional stiffness and weight.

In order to achieve greater flexural rigidity on keyboard base plates, is known, which is usually made of injection molded plastic material existing base plate with reinforcing elements in the form of ribs or Surrounds.

Modern keyboards, such as be used for personal computers, have more compact and powerful due to the use Components meanwhile a very high degree of compactness and therefore accompanied by low weight.

Was previously z. B. a return spring for each individual button comprehensive reset mechanism provided, so-called Safety mats made of an elastomeric material used to the Places below the key buttons with dome-shaped elevations (so-called switching domes) are provided, which when pressing a Button pressed in order to achieve the required restoring force for to surrender the button. Furthermore, instead of the earlier in Keyboards used circuit boards much lighter these days, multilayer switching foil sets used on which electrical contacts and Lines are attached.

The associated with the use of these lighter components Weight loss can go so far that it is already again is perceived as rather disturbing, e.g. B. because the keyboards in question only still a very low support weight and thus a relatively low stability show against unintentional slipping on a support surface. moreover these lighter components lead to an undesirable lowering of the Bending and torsional rigidity of the entire keyboard.

To achieve greater flexural and torsional rigidity on keyboards, it is known which is usually made of injection molded plastic material existing base plate with reinforcing elements in the form of ribs or To provide beads, such as. B. in patent application P 44 08 331.9 is described. However, this leads to a significantly more complex geometry of the Housing and the injection molds used in its manufacture what can also lead to demolding problems in unfavorable cases.

Keyboards with pivoting housing feet are also known whose separate bearings are attached to the base plate.

A keyboard according to the preamble of claim 1 is e.g. known from GB-A-2 250 380.

The object of the present invention is a construction for a keyboard propose a switch mat and a multilayer switch film set contains, where too high a degree of complexity in the geometry of the keyboard housing is avoided, and by integrating the housing feet in the Base plate increased bending and torsional stiffness as well as a higher one Weight is achieved, with a relatively simple assembly of the individual Keyboard components are preserved.

According to the invention, this object is achieved by a keyboard with an inserted Solved metal plate according to claim 1. From the features of claims 2 to 9 there are advantageous developments of the keyboard according to the invention.

In the keyboard according to the invention is between the base plate and the lowest of the foils in the switching foil set a metal plate in a form-fitting manner Cutout inserted in the base plate and between the deformable Safety mat and the base plate clamped. Furthermore, the rigidity increased by the housing feet integrated in the base plate.

It is also provided that the multilayer Switching film set is provided with one or more openings which each have a buffer element integrated in one piece in the switch mat reaches through and on top of the metal plate or on the top of the bottom switching foil for Lying comes, and that the top of the keyboard housing on its inside is provided with ribs, of which at least a part on the top of this Buffer elements rests. This will make the safety mat in the area Buffer elements pressed onto the underlying metal plate, causing this fixed and the film set is stored essentially floating.

Other types of fixation of the metal plate, which are known in practice as have proven to be unfavorable, especially z. B. an expensive Screw the metal plate into the base plate (which for cost reasons is undesirable) or attempting a play-free adjustment of the direct, d. H. without interposing the deformable safety mat touching components of the base plate, metal plate and the upper housing part with ribs.

In a modification of the invention The keyboard is the underside of the lowest switching foil with conductor tracks and / or provided contact points that are in electrical contact with the underlying metal plate, on which this bottom switching film is pressed, with an advantageous increase in electromagnetic Shielding results.

In addition, it can be provided that at least part of the inside of the Ribs attached in the housing provided in the base plate Engage locking elements and thereby the upper with the Firmly connect the lower half of the housing.

With the keyboard according to the invention on the underside of the Keyboard housing of the keyboard integrally integrated swivel Housing feet result from the base plate of the keyboard housing uplifting, essentially U-shaped reinforcing webs with one of the base plate facing away from the base plate. One of the bottom plate facing base area takes the trunnion for the swivel Case feet on.

Housing feet are in two or more of these reinforcing webs in one piece by means of bearing recesses on the reinforcing webs molded bearing journals.

The swiveling housing feet have one of their bearing recesses opposite, rounded support area and can be via a Angular range of at least 90 ° pivoted between two end positions be, by means of suitable locking devices in these End positions are fixed. The shape and size of the case feet are like this matched to the reinforcing bars that there is no in the one end position Part of a housing foot wider than the footprint of the reinforcing webs from the base plate extends away and at the same time part of the support area in is on the same level as the footprint of the reinforcing webs. in the when unfolded, the case feet protrude from the base of the Reinforcing webs. Due to the end positions of the folded or unfolded case feet result in two inclinations for the Keyboard that allows the operator to choose an inclination that is advantageous for him Keyboard should enable. In the keyboard according to the invention, the pivotable housing feet with a non-slip bead, which is designed so that in both end positions of the pivotable housing feet each a portion of this anti-slip bead the pad forms the maximum distance from the in the respective end position Has bottom plate and together with one in the front, the operator facing area of the keyboard lying anti-slip knob forms stable multi-point support.

Close to the reinforcement bars with swiveling housing feet can also each have several rib-shaped, different from the Base plate lifting webs may be attached, which are not up to the through the footprints of the reinforcement webs defined by the level Extend the base plate away. On the one hand, these serve as additional Reinforcing elements, and on the other hand they offer the operator the Possibility to put the fingertips on it when swiveling the housing feet support.

The advantages and features of the invention also result from the following description of an embodiment in connection with the claims and the drawings.

Fig. 1

einen Teilschnitt durch eine Tastatur mit eingelegter Metallplatte;

Fig. 2

eine Unteransicht auf die Bodenplatte der Tastatur;

Fig. 3

einen ersten parallel zum Schnitt in Fig. 1 verlaufenden Schnitt in einer ersten Ausschnittsvergrößerung im Bereich der gestrichelten Umrandung II; und

Fig. 4

einen zweiten parallel zum Schnitt in Fig. 1 verlaufenden Schnitt in einer zweiten Ausschnittsvergrößerung im Bereich der gestrichelten Umrandung III.

Fig. 5

eine Ausschnittsvergrößerung der in Fig. 2 gezeigten Bodenplatte im Bereich eines mit Lagerzapfen zur Aufnahme eines Gehäusefußes versehenen Verstärkungsstegs;

Fig. 6

einen Schnitt längs der Linie III-III in Fig. 5;

Fig. 7

eine Seitenansicht der Tastatur mit einem Teilschnitt durch den Verstärkungssteg, um die Seitenansicht eines Gehäusefußes sowohl in eingeklappter als auch in ausgeklappter Stellung zu zeigen;

Fig. 8

eine Seitenansicht auf einen Verstärkungssteg im Schnitt; und

Fig. 9

einen umklappbaren Gehäusefuß von der Seite.

Show it:

Fig. 1

a partial section through a keyboard with an inserted metal plate;

Fig. 2

a bottom view of the bottom plate of the keyboard;

Fig. 3

a first section parallel to the section in Figure 1 in a first enlarged section in the area of the dashed outline II. and

Fig. 4

a second section running parallel to the section in FIG. 1 in a second enlarged section in the area of the dashed border III.

Fig. 5

2 shows an enlarged detail of the base plate shown in FIG. 2 in the region of a reinforcing web provided with bearing pins for receiving a housing foot;

Fig. 6

a section along the line III-III in Fig. 5;

Fig. 7

a side view of the keyboard with a partial section through the reinforcing web to show the side view of a housing foot both in the folded and in the unfolded position;

Fig. 8

a side view of a reinforcing web in section; and

Fig. 9

a foldable housing base from the side.

Fig. 1 shows a partial section through an inventive keyboard 1 with a in a recess in the base plate 4 positively inserted metal plate 2. A multilayer switching foil set 3 rests on this metal plate. in the Upper housing part 8, individual key buttons 9 are mounted so that they can be moved vertically. These buttons are provided on their underside with plungers 49 that are on the top of one made of an elastomeric material Switch mat 7 in one piece integrated switching domes 47.

The switching mat 7 lies on the top of the top switching film. The multilayer film set 3 is provided with openings in several places, in immerse the buffer elements 42 integrally integrated in the switching mat 7. The inside of the upper housing part 8 is projecting downwards Stiffening ribs 46 are provided, of which at least a part on the Buffer elements 42 rests, and thereby to fix the switch mat 7 contributes. The deformable switch mat 7 serves as tolerance compensation between the (rigid) metal plate 2 and the (rigid) stiffening ribs 46th

Fig. 2 shows the base plate 4 of the keyboard 1. On the underside of this Bottom plate are several reinforcing webs 15a, 15b and 15c attached in plan view show a substantially U-shaped structure and in one piece, z. B. are integrated by injection molding into the base plate 4, and in which additionally pivotable housing feet 14 are mounted in journals 28. The Bearing journals are attached in the base area 36 of the reinforcing webs. These reinforcing webs 15a, 15b and 15c are preferably located in the backwards (in normal working position, with the down on a Storage area on the base plate 4, area facing away from the operator) the bottom plate 4. In addition to these reinforcement bars, additional rib-shaped webs 16 may be attached. These are preferably rib-shaped Web 16 parallel to the lateral front edges next to the Reinforcing webs 15a, 15c arranged, which, as explained later, that of the Serve fingers accessing the operator as a hold. The bottom plate 4 is by means of locking connections 23 on the upper housing part Keyboard 1 attached. 3 shows a first parallel to the section in FIG. 1 current cut in an enlarged section in the area of dashed outline II through the keyboard with inserted metal plate. The on the undersides of the vertically displaceable in the upper housing part 8 stored push buttons 9 attached plunger 49 lie on the switching domes 47 on. When a button 9 is pressed, it presses the underlying button Switch dome 47 and presses the extension 47a of the switch dome on the the upper switching film 3a underneath, which, like the very bottom lying switching film 3c on the inside with electrically conductive tracks and especially in the areas directly below the tappets with contact points is provided.

There is one between these two outer switching foils 3a, 3c So-called spacer film 3b, which the two outer films in one Keeps a distance from each other and thus electrical against each other isolated. In the area of the contact points at which the extensions 47a on the Press upper switching film 3a, but the spacer film 3b is with openings provided (due to the scale used not shown in Fig. 1, 3 and 4). When the extension 47a is pressed onto the upper switching film 3a, it becomes on this switching film 3a below the extension 47a electrical Contact point through the opening in the spacer film 3b on a underlying electrical contact point on the lower switching film 3c pressed so that the electrical contact between the two switching foils 3a, 3c is closed at this point. When you release the button 9 push the restoring forces acting in the elastomeric material of the safety mat 7 the switching dome 47 and thus the button 9 in its starting position back and the upper switching film 3a and the lower switching film 3c due to the restoring forces inherently acting in them and the spacer film 3b also returned to their starting position, in which they are replaced by the Spacer film 3b are separated, which causes the electrical contact between the upper and lower switching foil is lifted.

From practice it is known that the switching film set 3 in the installed state must be essentially floating to relieve tension Avoid changes in length due to changes in temperature or humidity. These tensions would inevitably change the switching travel and in the worst case lead to short circuits.

In order to achieve such a floating mounting of the switching foils, in the enlarged detail shown in Fig. 3 next to the individual Key buttons 9 and corresponding contact points assigned to them Breakthroughs in the spacer film 3b at some points between the Schaltdomen 47 through all three films breakthroughs provided by the integral in the switching mat 7 Buffer elements 42 as far as below the lower switching film 3c Reach through metal plate 2. This turns the film set 3 against the side Sliding stabilized. This stabilization can, as shown in Fig. 3, can be increased in that 8 stiffening ribs attached to the upper housing part 46 in the area of the upper switching film 3a Press the supporting buffer elements 42 onto the safety mat 7. A special one high stabilization of the safety mat combined with an advantageous The bending and torsional stiffness can be increased by that the stiffening ribs 46 are attached to the base plate 4 corresponding locking elements 48 can be snapped.

FIG. 4 shows a second section running parallel to the section in FIG. 1 in an enlarged section in the area of the dashed curve III the keyboard with an inserted metal plate. Alternatively to in connection with Fig. 3 embodiment described with through all three foils in Switching foil set 3 through openings can the openings in Area of the buffer elements 42 can also be designed so that they are only by the run through the upper switching film 3a and the spacer film 3b, but not through the lower switching film 3c, resulting in a pressing of the lower switching film 3c leads to the metal plate 2.

This pressing of the lower switching film 3c on the metal plate 2 results an additional advantage if, on the side facing away from the switch contacts, lower side of the lower switching film 3c or additional wiring Contact points are attached. In practice it has been shown that this increases the electromagnetic shielding, d. H. the EMC (= electromagnetic compatibility) leads. The one at the bottom of the lower one Switching film 3c attached cables or contact points through the buffer elements 42 at a defined location on the metal plate 2 pressed. This contacting makes said improved shielding reached.

FIG. 5 shows an enlarged section of the area around that in FIG. 2 left reinforcing web 15a, which with two journals 28 for Bearing of a housing foot 14 (shown in FIG. 2 at the reinforcing web 5c) and one lying essentially in the plane of the base plate 4 Locking tongue 33 and a standing area rising from this base plate 4 27 is provided.

FIG. 6 shows a section through the area shown in FIG. 5 along the line IV-IV. The next to the reinforcing web 15a to the end face of the base plate 4 rib-shaped webs 16 arranged in addition to the Reinforcing webs 15 for increasing the flexural rigidity of the base plate. They do not have the same height above the base plate 4 as that Reinforcing webs 15a, 15b and 15c.

The size and shape of the housing feet (not shown in FIG. 6) are matched to the reinforcing webs 15a, 15b and 15c in such a way that the housing feet do not protrude beyond the standing surface 27 of the reinforcing webs when folded. Thus, the base plate 4 of the keyboard according to the invention rests with the base on the support surface indicated by the broken line a when the housing feet are folded in. If there is a sufficient gap between the rib-shaped webs 16 and the support surface, the operator can support a finger behind the rib-shaped webs 16 with the reinforcement webs 15a, 15c resting on the support surface a and slide another finger between the rib-shaped webs 16 and the support surface, around the to be pivoted in the reinforcing web 15a or 15c, folded housing foot 14.

FIG. 7 shows a side view of the keyboard 1, with a section through the reinforcing web 15a in order to show a housing foot both in the folded-in position 14a and in the unfolded position 14b. For both positions of the housing base, the possible orientations of the support surfaces relative to the keyboard 1 with associated inclination angles α and β are indicated by dashed lines a and b . The inclination angles .alpha. And .beta. Are each determined by the anti-slip knob 22 located on the front of the keyboard 1 facing the operator and the position of the housing foot 14a or 14b. The housing base is mounted in the bearing journal 28 and can be pivoted between the two end positions 14a and 14b shown in FIG. 7.

The housing base is provided with a slightly rounded support area 29 facing away from the journal 28, which is provided with a z. B. is provided in a groove running, anti-slip bead 19. The size and shape of the housing base and this anti-slip bead 19 are matched to the reinforcing web 15 in such a way that the housing base does not protrude in the folded state 14a beyond the bearing surface a extending through the anti-slip knob 22 and the standing surface 27 of the reinforcing web 15. Section 19a of this anti-slip bead lies in the plane of the support surface a . By the above the base plate 4 reinforcing web 15 in connection with the in the folded state reaching to the level of the support surface a housing foot 14a ensures that the keyboard 1 shows a pre-inclination towards the operator in the folded state of the housing foot, which is determined by the inclination angle α is, and that the keyboard is further supported by the resting of the portion 19a of the anti-slip bead 19 on the support surface a non-slip.

If the housing foot is pivoted around the bearing pin 28 through an angle of at least 90 ° into its unfolded position, the inclination of the keyboard 1 to the new support plane b is now determined by the inclination angle β.

8 and 9 show enlarged representations of a reinforcing web 15 with bearing pin 28 or a housing foot 14 that can be placed on the bearing journal 28 with the bearing recess 47. The housing foot 14 is provided with two locking notches 18 on the outer circumference of its anchoring region 26 pivotably mounted on the bearing journal 28 , which are offset from one another by at least 90 ° along the circumference, and into which a locking rib 17, which is attached to the latching tongue 33 of the reinforcing web 15 shown in FIG. 8, engages, in order to thereby pivot the pivotable housing foot 14 in its two end positions 14a and 14b (see FIG 7) to fix. The housing foot is provided with a knob 32 which rests on the inner wall 35 of the reinforcing web 15 when the housing foot 14 is folded out. Furthermore, the housing base 14 is rounded on its support area 29 facing away from the bearing recesses 37 and with a z. B. in a groove guided, partially circumferential, anti-slip bead 19 which, as explained in connection with FIG. 7, rests in both snap-in end positions 14a and 14b of the pivotable housing foot 14 on the respective level of the contact surface a and b and so for one keyboard provides increased slip resistance.

To place the housing foot 14 on the bearing pin 28 is on both sides A slightly wedge-shaped cutout 38 is provided in the central longitudinal plane narrowest point is smaller than the diameter of the bearing recess. By this configuration, the housing foot is easy on the journal 28 in the postponed position and snaps into place.

In summary, the advantages of the invention are therefore inexpensive Increasing your own weight accompanied by an improvement in Torsion and bending stiffness in the interaction of the housing feet with a simple and play-free clamping of the metal plate without one complex geometry for stiffening grooves or beads in the keyboard housing require. The metal plate also provides an easy way to Improve electromagnetic compatibility by adding one to their Bottom with electrical contacts provided lower switching film 3c on the Metal plate 2 is pressed.

Claims (9)

1. Keyboard (1) with inlaid switching mat (7) and multi-layer switching film set (3), wherein between the bottom tray (4) and the lowermost of the switching films in the switching film set a metal plate (2) is laid in the keyboard in form-locking relationship and clamped between the switching mat and the bottom tray (4), wherein reinforcing webs (15) which are integrated in one piece in the lower side of the keyboard housing and project above the bottom tray (4) of the keyboard housing are provided, which extend in a U shape and have a stand surface (27) facing away from the bottom tray, and wherein in the base region (36) of the reinforcing webs (15) there are journals (28) for pivotable housing feet (14), characterised in that the housing feet (14) can be latched by latch notches (18) in latch ribs (17), and in that the multi-layer switching film set (3) is provided with one or more apertures which pass right through or only through the upper layers of the multi-layer switching film set and through each of which a buffer element (42) integrated in one piece in the switching mat (7) passes and comes to lie on the upper side of the metal plate (2) or on the upper side of the lowermost switching film.
2. Keyboard according to claim 1, characterised in that the lower side of the lowermost switching film (3c) is provided with strip conductors and/or contact points which are in electrical contact with the metal plate (2) underneath.
3. Keyboard according to either of claims 1 or 2, characterised in that the upper housing portion (8) of the keyboard (1) is provided on its inner side with ribs (46) at least some of which rest on the upper side of the buffer elements (42).
4. Keyboard according to any of claims 1 to 3, characterised in that at least some of the ribs (46) of the upper housing portion (8) engage in corresponding latch elements (48) mounted on the bottom tray (4), and in that the buffer elements (42) are located directly below these points of engagement.
5. Keyboard according to one or more of claims 1 to 4, characterised in that the housing feet (14) at their end opposite the mounting recesses (37) have a support region (29) provided with a non-slip bead (19), in that the housing feet (14) are pivotable through an angular range of at least 90° between two end positions, wherein they can be fixed by means of suitable latch devices in these end positions, in that the housing feet (14) are coordinated in shape and size with the reinforcing webs (15) in such a way that in one end position no part of a housing foot (14) protrudes away from the bottom tray (4) further than the stand surface (27) of the reinforcing webs (15) and at the same time part of the support region (29) lies in the same plane as the stand surface (27) of the reinforcing webs (15), and in that in the other end position some of the housing feet (14) extend away from the bottom tray (4) further than the stand surface (27) of the reinforcing webs (15).
6. Keyboard according to claim 5, characterised in that the non-slip bead (29) is mounted in a groove extending partially around the support region, and in that in both end positions of the pivotable housing feet (14) in each case a partial region of this non-slip bead (19) forms the region of the housing foot (14) which in the respective end position exhibits the maximum distance from the bottom tray (4).
7. Keyboard according to claim 5 or 6, characterised in that the pivotable housing feet (14) in their anchoring region (26) are provided with two latch notches (18) in which engage the latch ribs (17) which are mounted on the bottom tray (4) or on the base regions (36) of the reinforcing webs (15) and which fix the pivotable housing feet (14) in their two end positions.
8. Keyboard according to one or more of claims 1 to 7, characterised in that adjacent to the reinforcing webs (15) provided with pivotable housing feet (14) are additionally mounted in each case several rib-like webs (16) protruding from the bottom tray (4), and in that these rib-like webs (16) extend away from the bottom tray (4) not as far as the plane fixed by the stand surface (27) of the reinforcing webs (15).
9. Keyboard according to claim 7, characterised in that the bottom tray (4) between the arms of the reinforcing webs (15) extending in a U shape is designed as a latch tongue (33) which engages by a latch rib (17) in the latch notches (18) on the housing feet (14).

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