DE20216287U1 - Piezo switches - Google Patents

Description

Dipl.-Phys. WOL*FGANG&Oacgr;&Ogr;&Ugr;" '"· PATENT ATTORNEY

EUROPEAN PATENT ATTORNEY

Applicant:

Schurter GmbH Elsässer Str. 3 79346 Endingen

D-79108 FREIBURG
Zaehringer Str. 373

Telephone 0761/554521 Fax 07 61/55 45 25

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1267

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Date

22.10.2002

Piezo button

The invention relates to a piezo button according to the preamble of claim 1.

Conventional, somewhat vandal-proof piezo buttons are usually installed in a sleeve-shaped metal housing, the front element of which is made in one piece with the actual housing and in which the piezo disk is located. These piezo buttons are characterized by the fact that they are resistant to freezing and sticking. The reason for this is that the housing has a continuous front. When pressure is applied to this front, it bends slightly. This deflects the piezo disk behind the front and emits a voltage due to the piezo effect. This voltage is detected by electronics and converted into a switching signal. The associated evaluation electronics can either be part of the piezo button or an external component.

In order to be able to deflect the front of the housing, the thickness of the material must not be too great. It is therefore in the range of a few 1/10 mm. But this is also a disadvantage of these conventional piezo buttons. The thin front can be relatively easily pierced with a knife, for example, or dented with a blunt object. The resulting deformation causes destruction or permanent pre-stressing of the piezo disk located directly behind the front. Both lead to a total failure of the piezo button.

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Based on this, the invention is based on the object of creating a piezo button of the type specified at the beginning with improved vandal protection.

The technical
Claim 1.

Solution is characterized by the features in the characteristic of the

This creates a super vandal-proof piezo button with a high IK protection level. The basic idea of the piezo button according to the invention is to break through the metal front of the housing and instead use an actuating disc that is separate from the housing. This actuating disc can be made of metal, bulletproof glass, plastic, etc. The actuating disc is mounted on the elastomer element that is also provided and can therefore be deflected in the required area. Theoretically, the actuating disc can be as thick as desired and is therefore considerably more vandal-proof than the thin front of conventional piezo buttons. The elastomer element absorbs blows from blunt objects and deformations of the actuating disc due to such blows from blunt objects no longer lead to total failure. In addition, if the actuating disc is thick enough, it can no longer be pierced with sharp objects. Overall, the piezo button according to the invention is therefore considerably more vandal-proof than conventional piezo buttons.

A wide variety of technical implementations and forms are conceivable as an elastomer element. Preferably, the elastomer element according to the embodiment in claim 2 is an elastomer disk.

The development according to claim 3 creates a bearing for the actuating disk within the housing. Preferably, the radially inwardly projecting projection extends around the entire circumference of the housing, wherein the elastomer disk presses the actuating disk against this projection.

The development according to claim 4 creates a seal on the back of the actuating disk around the peripheral edge. The sealing ring can be a silicone ring.

The further development according to claim 5 has the advantage that the entire interior area in the area of the elastomer disk is filled with a likewise elastomeric casting material, so that overall an elastomeric structure is obtained in this area.

The development according to claim 6 creates a rigid support for the piezo disk including hybrid with cable. The ring can be a clamping ring or a pressure ring.

Finally, the further development according to claim 7 is to be seen in connection with the previously described soft casting in the area of the elastomer disk. By filling the area of the piezo disk with a hard casting material according to the further development in claim 7, a rigid mounting of the piezo disk inside the housing is created, so that the pressure exerted on the actuating disk is fully transferred to the piezo disk.

An embodiment of a piezo button according to the invention is described below with reference to the drawing, which shows a schematic longitudinal section through such a piezo button.

The piezo button has a sleeve-shaped housing 1. Its upper edge - in the drawing - has a circumferential, nose-shaped and radially inward-facing projection 2.

An actuating disk 3 made of metal, bulletproof glass, plastic or the like rests against this projection 2. The peripheral edge of this actuating disk 3 is sealed to the inner wall of the housing 1 by means of a sealing ring 4 made of silicone.

Furthermore, a ring 5 is fixedly arranged inside the housing 1. A piezo disk 6 is mounted on this ring 5 and is completely cast with a hard casting material 7.

An elastomer disk 8 is located between the piezo disk 6 and the actuating disk 3. This space within the housing 1 in the area of this elastomer disk 8 is also filled with a potting material 9, which, however, is a soft potting material 9 in contrast to the hard potting material 7.

It works as follows:

The actuating disk 3 is movably mounted on the elastomer disk 8 and can be deflected in the required range. This means that when pressure is exerted on the actuating disk 3, the pressure is exerted via the elastomer disk 8 onto the piezo disk 6, which emits a voltage due to the piezo effect. Since the actuating disk 3 can be as thick as desired, it cannot be struck with sharp objects if it is of the appropriate thickness.

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objects. Any deformation of the metal disk caused by impacts with blunt objects is compensated by the elastomer disk 8 and no longer leads to a total failure of the piezo button.

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List of reference symbols

Housing

head Start

Actuating disc

Sealing ring

ring

Piezo disc

Casting material (hard)

Elastomer disc

Casting material (soft)

Claims (7)

1. Piezo button
with a housing ( 1 ),
with a piezo disk ( 6 ) arranged in the housing ( 1 ) and
with a movable actuating element arranged in front of the piezo disc ( 6 ), which is in operative connection with the piezo disc ( 6 ),
characterized ,
that the actuating element is a rigid actuating disc ( 3 ) formed separately from the housing ( 1 ),
that an elastomer element is arranged between this actuating disc ( 3 ) and the piezo disc ( 6 ) and
that the actuating disk ( 3 ) is movably mounted on this elastomer element in the housing ( 1 ) in such a way that the pressure exerted on the actuating disk ( 3 ) can be transferred via the elastomer element to the piezo disk ( 6 ). 2. Piezo button according to the preceding claim, characterized in that the elastomer element is an elastomer disk ( 8 ). 3. Piezo button according to one of the preceding claims, characterized in that the housing ( 1 ) has an inwardly projecting, circumferential projection ( 2 ) against which the circumferential edge of the actuating disk ( 3 ) rests. 4. Piezo button according to claim 3, characterized in that a circumferential elastomeric sealing ring ( 4 ) is arranged on the other side of the actuating disk ( 3 ) in the housing ( 1 ). 5. Piezo button according to one of the preceding claims, characterized in that the area inside the housing ( 1 ) with the elastomer element is filled with a soft, elastomeric potting material ( 9 ). 6. Piezo button according to one of the preceding claims, characterized in that a ring ( 5 ) is arranged in the housing ( 1 ) as a support for the piezo disk ( 6 ). 7. Piezo button according to one of the preceding claims, characterized in that the area inside the housing ( 1 ) with the piezo disk ( 6 ) is filled with a hard potting material ( 7 ).