EP0354312A1 - Support mechanism for a multiple key - Google Patents

Abstract

A support mechanism provided for multi-key heads consists of a U-shaped wire bracket (26), in which the free ends (30) of the legs are bent at right angles inwards or parallel to the base section (28) of the wire bracket (26). The base section (28) of the wire bracket (26) is rotatably mounted off-center on the key head parallel to the longitudinal central axis, an assembly stop (32) running from the bearing, which in one assembly causes the wire bracket (26) to hang down during assembly due to its own weight holds oblique mounting position. Bracket guides (37) are provided on the transverse sides of the key base (11), into which the free ends (30) of the legs can be inserted vertically during assembly and horizontally displaceable when the key head is actuated.

Description

The invention relates to a support mechanism for multi-button heads with a U-shaped wire bracket, which is pivotally mounted on the button head on both sides of the tappet guide and near the outer edges and on the button base and allows an essentially tilt-free tappet actuation, the free ends of the U-shaped bent Wire bracket can be moved laterally in the holder provided when you press the button head.

For the actuation behavior of key switches, as they are usually used in typewriters, the more favorable the switching behavior, the more the key head in the center, i. is applied above the ram guide. With such an actuation in the key center, i.e. There are no tilting moments introduced into the guide above the ram guide.

In conventional writing keyboards, key heads with a 1: 1 aspect ratio are generally used, with no disturbing tilting moments occurring in the layout of approximately 18 x 18 mm used, in particular since the finger recess provided on the top of the key head favors the central actuation.

A completely different actuation behavior results with so-called multi-key heads, which have a larger extension in one direction, either in the vertical or horizontal direction, ie an edge ratio greater than 1: 1. Such multi-key heads are preferably used for special functions, such as the line feed, the shift key or the space key. Because of the larger extension of the key head in one direction, it is no longer guaranteed that it is operated centrally, but rather the out-of-center operation is the rule.

However, if the button head is pressed down at its edge and there are no other mechanical precautions under the head, tilting moments occur due to the eccentric loading, which require a higher actuation force due to the higher friction of the tappet guide triggered thereby. In extreme cases, even the actuation of the button can no longer be ensured and the button head can be pushed out of the attachment on the button module.

In order to overcome these difficulties, it is known to provide an actuation mechanism in the case of multiple keys, which consists of a U-shaped wire bracket which is directly or indirectly movably connected to the key head and the key base.
The connection points on the key top are located near the two outer edges of the key tops, the free ends of the U-shaped mounting bracket running through bores and being held so that they can be tilted and displaced. The base section of the wire bracket is rotatably mounted on the key base.

In the case of an off-center actuation via the key head, the force occurring is deflected via the wire bracket rotatably mounted in the key base and redirected to the opposite side of the key head. In this way, even when the button head is actuated off-center, the side of the button head opposite the force application is pulled downward by the wire bracket, resulting in a distributed force instruction and no or no significant tilting moment acting on the guide of the button tappet. This always ensures perfect actuation behavior.

Although such a support mechanism fulfills the required function satisfactorily, the known solution has a serious disadvantage if the switch and in particular the button head are to be installed automatically on the button base.
The well-known U-shaped wire bracket can namely be threaded with an automat only with extreme effort into the mechanical support provided on the key top, so that manual assembly is still preferred for reasons of cost and because of the larger rejects that cannot be avoided in semi-automatic production. In addition, a wire bracket held in this way on the key head cannot be installed by mechanically pressing the multiple heads onto the key base, so that here too there is a need for manual assembly.

From this disadvantage, the problem underlying the invention is derived, namely that the support mechanism for multiple key heads is to be changed such that an automatic assembly together with the square key heads is possible in one automatic operation.

Starting from the support mechanism mentioned at the outset, this object is achieved in that the ends of the free legs of the U-shaped wire bracket are bent approximately at right angles, namely parallel to the base section, in that the base section of the wire bracket on the key head is eccentrically parallel to the longitudinal center axis in the mechanism carriers is rotatably mounted, the wire bracket being held in an oblique mounting position by a stop, and that the key base has bracket guides on its transverse sides, into which the free ends can be inserted vertically during mounting and can be displaced horizontally when the button head is actuated.

This configuration of the support mechanism makes it possible to use all of the key heads preassembled with the individual parts, i.e. Single buttons as well as multiple buttons can be installed automatically by completely attaching them from above and pressing them on.

• Fig. 1: eine rückseitige Ansicht auf eine Mehrfachtaste mit einer Stützmechanik gemäß der Erfindung;
• Fig. 2: eine Seitenansicht auf eine Mehrfachtaste in einer ersten Position beim Aufsetzen des Tastenkopfes;
• Fig. 3: eine Seitenansicht einer Mehrfachtaste mit aufgesetztem Tastenkopf.

The advantages and features of the invention result from the following description of an exemplary embodiment in conjunction with the claims and the drawing. Show it:

• 1: a rear view of a multi-button with a support mechanism according to the invention;
• 2 shows a side view of a multi-button in a first position when the button head is placed;
• Fig. 3: a side view of a multi-key with attached key.

The multiple key shown in the figures is intended for use in a membrane keyboard, wherein the key base 11 is fastened directly to a foil set 12 and to the carrier plate 13 running under the foil set 12 by riveting.
The inside of the key base contains a conventional contact, which is actuated via a plunger 15 and a key head 16 attached to it.

The plunger 15 is inserted into a socket 16 on the underside of the key head 18, this socket 16 being located in the center with respect to the longitudinal and transverse extension of the multiple key head.

On both sides of the plug-in socket 16, namely close to the outer edges of the multi-key head, further plug-in sockets 20 are provided, in each of which a mechanical support 22 is inserted.

This mechanical carrier 22 is shown in its side view from FIGS. 2 and 3 and reveals that it has a rotary bearing 24 in the region of the front edge of the multi-key head, which is designed as a snap-in bearing and serves to receive a wire bracket 26.

As can be seen from Fig. 1, this wire bracket 26 is bent in a U-shape, so that there is a long base section 28 which extends approximately over the entire length of the multi-key head and snapped into the pivot bearing 24 in the mechanical support 22 at sections as far out as possible can be.

The free ends 30 of the wire bracket 26 are bent inwards so that they run parallel to the base section 28 and end in a plane which extends somewhat outside the outer boundary plane of the key socket 11.

The mechanical support 22 extends to the central region of the multi-key head and has an upwardly projecting pin which can be inserted into the plug-in socket 16.

Outside the pivot bearing 24, a mounting stop 32 runs obliquely downwards at an angle, so that the wire bracket 26 inserted into the pivot bearing 24 with the base section is held in an inclined position in the hanging state, which, as is evident from the later explanation, ensures that that the free ends 30 of the wire bracket are fixed in the correct mounting position when the multi-button head is placed on the button base.

A guide rib 36 is also provided on the mechanical support 22, which runs along the inside of the bent wire bracket when the button is pressed and ensures a horizontal alignment.

On the transverse sides of the key base 11 shown in FIGS. 1 and 2 is as A guide projection 40 is provided for the bracket guide 37 for the free end 30 of the wire bracket. A guide shoulder 38 runs vertically downward at a distance from the guide projection 40 which corresponds approximately to two or more times the diameter of the wire bracket 26.

The guide projection 40 consists of an L-shaped rib projecting over the transverse side of the key base, the long leg of which runs parallel to the film set or parallel to a projecting base edge 42 of the key base. This creates a recess extending in the transverse direction, the inner guide shoulder of the guide projection 40 running at a distance from the base edge which is somewhat larger than the diameter of the free end 30 of the wire bracket 26.

Such a guide approach is attached to both sides of the key base.

To assemble the keyboard, the individual key bases are placed on the foil set and riveted to the carrier plate.

To attach the button heads, they are placed in a pallet with all pre-assembled parts and sucked in using a template. When the button heads held in this way are put on, the wire brackets mounted on the multiple heads fall down due to their own weight and come to rest against the mounting stop 32, as a result of which they assume the mounting position necessary for automatic mounting. In this position, the key heads are moved further downward, so that the free ends 30 of the wire brackets 26 are moved down between the guide shoulder 38 and the guide projection 40 to the base edge 42 until they come to bear against it. This position is shown in Fig. 3 with excellent lines and represents the position of the fully assembled button.

When the multi-button head is actuated, it is moved further downward, as a result of which the free ends 30 of the wire bracket 26 move laterally between the guide projection 40 and the base edge 42, as can be seen from the broken line in FIG. 3.

Since the wire clips rest loosely on the inside of the guide ribs 36, a horizontal alignment is also ensured.

If an actuation takes place off-center in the case of a multi-key head assembled in this way, it is ensured that the forces are also transmitted to the other end of the head through the wire bracket and thus a two-sided introduction of the actuating force is ensured while preventing a tilting moment.

Claims (4)

1.Support mechanism for multi-button heads with a U-shaped wire bracket, which is pivotally mounted on the button head on both sides of the tappet guide and near the outer edges as well as on the button base and allows an essentially tilt-free tappet actuation, the free ends of the U-shaped wire bracket at Pressing the button head can be moved laterally in the holder provided;
characterized by
that the ends (30) of the free legs of the U-shaped wire bracket (26) are bent approximately at right angles and parallel to the base section (28) inwards;
that the base section (28) of the wire bracket (26) on the key top (18) is rotatably mounted off-center in the mechanical supports (22) parallel to the longitudinal central axis, the bearing brackets being held in an oblique mounting position by a mounting stop (32),
and that the key base (11) has bracket guides (37, 38, 40, 42) on its transverse sides, into which the free ends (30) can be inserted vertically during assembly and horizontally displaceable when the key top is actuated. 2. support mechanism according to claim 1,
characterized by
that the mechanical support (22) for holding the base section (28) of the wire bracket (26) are provided with rotary bearings (24) to which a downwardly inclined mounting stop (32) is assigned, which hangs freely on the button head wire bracket (26) in holds an inclined position suitable for installation. 3. support mechanism according to claims 1 or 2,
characterized by
that the guides on the key base consist of a vertical bracket guide for insertion and a transverse guide defined by a guide projection (40) and a base edge (42) of the key base (11). 4. Support mechanism according to one of claims 1-3,
characterized by
that on the mechanical support (22) guide ribs (36) are attached in order to position the wire bracket (26) horizontally in the rest position and in the operating position relative to the key base (11) and the mechanical supports (22).

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