DE8400256U1 - Push button - Google Patents

Description

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The invention relates to a push button of the type specified in the preamble of claim 1.

Such pushbuttons are often used in keyboard, also used in particular in keypads for telephones. There is a requirement that the The actuation time of the contact when the button is pressed lasts at least a few tenths of a second. In order to avoid expensive electronic switching means such as debouncing devices and monostable switching elements, it is known to train the switch / that the contact before the end of the stroke when the button is pressed is actuated and this actuation state lasts until the end stop is reached. With the known buttons In this way, the contact is operated by lateral pressure, whereby the button element - in the manner of a Söhleif- bahn - slides along a contact spring or the like, so that the contact in each case until it reaches the The end of the travel remains actuated.

The disadvantage here is that the contact elements or their actuators must be attached to the side of the button element.

In the case of compact keypads and especially in the case of keypads for compact telephones, however, there is the Requirement that the keys should be attached as closely as possible so that the keys required for a 12-key field

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There is space for the necessary base area, for example, on the inner surface of a handset.

The invention specified in claim 1 is therefore based on the object of specifying a pushbutton switch of the type mentioned at the outset which "assumes its actuating function already during the key travel and until the end of the travel maintains, whereby the area occupied by the individual button should be as small as possible.

It is particularly advantageous that the mechanical spring elements can at least partially consist of elastic plastic and in those components which who make contacts, can be integrated into them * It is irrelevant whether the contacts to be operated are designed as work or break contacts.

In a preferred embodiment of the invention, one of the elastic elements is designed as a helical spring and can therefore be conveniently inserted into the interior of the operating button, so that the resulting extension of the spring element provides good linearity over the Actuating travel is achievable.

The invention is based on the knowledge that an elastic element is provided between the keyboard and the contact should be, which takes up an upper stroke, whereby the period of time to cover the upper stroke with normal actuation (and possibly the way back to the release of the contact)

3d with normal operation, the minimum operating time of the Contact to trigger the desired function.

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speaks. The dimensioning is preferably carried out in the Neise that only the return path of the key element into his Starting position, the duration of which is determined solely by the elasticity of this spring element, be greater should be the minimum time, since this path is not subject to the influence of the operator, because - especially with compact keypads - the individual keys cannot be reached with the fingers, for example to be pulled out more quickly. on In this way, the desired function is ensured regardless of the type of actuation.

Another elastic element is required to cancel the contact function after releasing the button borrowed, which brought the idle state of the contact back represents. In this case, an element is preferably used which is connected in series with the first-mentioned spring element, the spring stiffness being lower, so that this element pressed together first and thus the Contact state is established. When the button springs back In its starting position, the first-mentioned spring element is also relaxed first, so that the contact state is maintained until shortly before reaching the end position of the button. Only then is the contact state by relaxing the second spring element as well canceled again. The delay in the way back is supported in particular when the key element is subjected to a slight mechanical friction on its actuation path.

The spring element connected to the contact must have a spring stiffness which is large enough to the

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Key - also opposite to gravity - safe in f; returned to their starting position. Is this elasticity insufficient or the second-mentioned elasticity is missing Element, a second spring is inserted instead, which is located directly between a fixed reference point (the contact level) and the key is effective. The maximum spring stiffness applies to this second spring no special dimensions as for the first-mentioned spring elements. The spring stiffness must if necessary however, it should be chosen to be low if there is a certain minimum period of time for the return movement of the key arrives, with the spring stiffness on the other hand as well must be large enough to generate the necessary restoring force for the button.

In other preferred embodiments of the invention, the second-mentioned elastic element with the contact is conical and formed as part of a contact mat - preferably consisting of silicone rubber. As the actuation path for the contact is small compared to the actuation travel of the key element, the required Diameter of the frustoconical elastic element as part of the contact mat is relatively small Value so that the keys can be built up close together.

When the first-mentioned elastic element is designed as a helical spring and inside the key element is arranged, the key itself can also be relatively be made slim so that the spaces between the keys are sufficiently large to accommodate the

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To feel the individual keys for actuation safely with the fingers and to exclude operating errors.

Advantageous further developments of the invention are characterized in the subclaims or are discussed in the next Described in detail together with a preferred embodiment of the invention.

In the embodiment shown in the figure,

if a normally open contact is to be actuated, it consists of a contact element 1 and a mating contact 2. These are in a elastic mat 3, consisting of silicone rubber embedded, which has a frustoconical elevation at each Has push button, which is elastically resilient and when pressure is applied from above, elements 1 and 2 are brought closer together Making contact possible. It is actuated by a button 5, which is guided within an opening of a housing 6 with an adapted cross-section and widens downwards so that it is in the resting position tion by means of the stop surface 7 in their way through the Housing 6 is limited. Inside the button 5, a helical spring 8 is provided, which on the one hand attaches itself to an inner surface of the button 5 and on the other hand on the conical surface of the truncated cone 4 of the contact mat 3 acts. The helical spring 8 is now dimensioned in such a way that, in its relaxed position, it forms the truncated cone 4 not yet depressed and the key 5 holds in its rest position.

The spring stiffness of the helical spring 8 is greater than that of the cone 4, so that when the button is pressed

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the cone is first depressed and makes contact between elements 1 and 2. The hub of the The key is limited by a pin 9 arranged in the helical spring, which on the one hand is the visual cube spring leads, and on the other hand also serves as a support. This results in a defined touch feeling for the operator, so that the activity is psychologically inevitable until this "hard" limit is reached ur> d thus also a confirmation is given that the the desired function triggered by the push button is safely carried out.

After releasing button 5, it returns to its starting position lifted back, the way through the friction between the key outer surface 5 and the opening is possibly deliberately slightly hindered in the housing surface 6, so that the key return stroke for a time requires, which is greater than the desired minimum contact time when the button is pressed once.

Similar key elements - which are not shown in the drawing, can be lined up close together, so that the desired compact design can be achieved. In particular, the truncated cone 4 can be dimensioned so that that it does not protrude laterally beyond the cross section of the key element 5 below the housing surface 6 and thus the size is determined exclusively by the dimensions of the button 7 used.

When actuated, due to the low elasticity of the, the contact elements are in their rest position

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holding elastic element already shortly after the beginning of the path of the tactile working condition, which is up to complete depression is retained and thus a predetermined minimum value with the usual manual actuation does not fall below. This minimum contact time is increased by additional measures, which - how shown - affect the time required for the return stroke.

The invention is not limited in its implementation to the example given above. Rather, a large number of variants are conceivable, which of the one shown Make use of the solution even if the designs are fundamentally different.

Claims (6)

ELMEG - January 2nd, 1984 Elektro-Mechanik GmbH D-3150 Peine push button claims 1. Push button, especially for use with a keypad for a compact telephone with at least one elastic element, which exerts a force on the button element opposite to the actuation direction, and a contact element / on the Button element acts, / 2 • · · * · ftf · f · E83.G9 page 2 characterized, that a first elastic element between the button element (5) and the actuated contact element {l _r 2) is arranged, the spring stiffness of which is greater than the spring stiffness of a second elastic element (4), which holds the actuated contact element in its rest position. 2. Push button according to claim 1, characterized in that with only low spring stiffness of the second elastic element, or on whose place, a further elastic element (8) is provided, which between the button (5) on the one hand and a fixed reference point is clamped on the other hand and against the direction of actuation of the push button to Driving back the key element is biased in its rest position. 3. Push button according to one of the preceding claims, characterized in that the erote and / or further elastic element (8) is designed as a helical spring. 4. Push button according to claim 3, characterized in that that the helical spring (8} at least partially inside the hollow Button (5) is arranged and in the relaxed state in «I till E83.G9 page 3 Direction of the contact elements (1, 2) protrudes from this. 5. Push button according to Anspxuch .4 / characterized in that the screw pin (8) is also guided over a pin (9), which is with its lower surface is supported at least indirectly on the contact element (1). 10 6. Push button according to one of the preceding claims, characterized in that the second elastic element as a frustoconical part (4) a contact mat (1) is formed. / 4