DE7133085U - VIBRATION SENSORS FOR ALARM SYSTEMS - Google Patents

Description

PATENT ADVOCATE Reinhard Kinne

b2. Nov 1971

• 000 MÖNCHEN 60 FRITZ'BtRNI'tTR. S.

IB-Hti / MM «

ι «« wen ^{G 71 5J} ^ ⁵ - ³

8031 Stockdorf, Mitterweg 37

Vibration sensor for alarm systems

The innovation relates - to a vibration sensor for alarm systems.

In the case of alarm systems, the problem arises in certain applications by determining ion vibrations, which caused by an unauthorized action, trigger an alarm. On the other hand, an alarm from such may say Vibrations that occur during normal operation are not triggered. Especially with alarm systems that can trigger a police emergency call, a false alarm should be ruled out with certainty.

Vibration sensors are already known in which an oscillating mass is pressed against a contact by a spring will. If this vibration sensor is shaken, the vibrating mass is removed from the contact against the spring force thrown away, causing an open circuit

141

is brought about, which is used to trigger an alarm signal. Such vibration sensors already speak to very low frequencies, which occur, for example, when a passer-by unintentionally with the Hand or elbow against a secured pane of glass. An increase in the spring force increases the Frequency of this vibration sensor, however, makes it less sensitive, i.e. the oscillation amplitude causing the contact to be interrupted must be greater. In addition, such a vibration sensor has the disadvantage that its contacts, in particular because of the on the The inside of glass panes, which are normally high in moisture, can be easily corroded as a result the tendency to trigger nuisance alarms is increased.

The innovation is based on the task of creating a vibration sensor for alarm systems that only responds to vibrations with high frequencies - ultrasound - responds sensitively and cannot be influenced by interference.

This task is solved by one for ultrasound permeable disc, which forms a wall of a housing and on the inside of which sits a piezoelectric ceramic disc, through one in the housing to another Wall-mounted transformer, whose primary connections to the Electrodes of the piezoelectric ceramic disc connected

.. 3 -

and the secondary connections of which are connected to a shielded cable which is passed through a housing wall opening Is introduced into the housing, and by a preferably made of plastic molding compound that the remaining Fills the cavity in the housing completely.

The log, which is permeable to ultrasound, is preferably made of glass. However, it can also be made of plastic or such as exist. The piezoelectric ceramic disk is glued to the ultrasound-permeable disk. To secure a pane of glass, for example a shop window or a display window, the Vibration sensor according to the innovation with that for ultrasound The permeable pane is glued to the glass pane to be secured by means of an appropriate adhesive. The one in this Vibrations occurring in the glass pane are thus transmitted to the ultrasound-permeable pane transferred piezoelectric ceramic disc. Their natural frequency is in the ultrasonic range, so they only emits a significant output signal when the frequency of the vibrations transmitted to it is above its Natural frequency and thus also in the ultrasonic range. This can cause low-frequency vibrations that for example, if the secured glass pane is accidentally knocked, it usually occurs frequently, Do not trigger a false arm, while the ultrasonic vibrations that constantly occur with splintering glass panes are also involved Security trigger an alarm.

I ·

The arrangement of the transformer in the housing enables the closed-circuit current monitoring of all elements and lines required for alarm systems. This RuhestroNuberr? .Chung JLtUiLi at the aetterungsgesäSen Sehvliigus & srühler take place in that a direct current loop is closed via the secondary winding of the transformer. A separate monitoring of the primary circuit of the transformer is not necessary, since it is completely enclosed by the housing and practically cannot be separated from the outside.

So that the piezoelectric xeramik disc close to the for ultrasound permeable pane can be applied,

ä "and yet see a T.jyh <mAohTmB mifgebx ^ atht on both sides

can be, a recess is provided in the ultrasound-permeable pane, which is partially of the piezoelectric ceramic disc is covered. The relevant solder connection then lies in this recess of the piezoelectric ceramic disc, an opening being left free through the recess through which a connection line can be led to this solder connection can.

The body of the housing is preferably made of plastic. However, other materials are also possible. For example metal can also be used. The housing is preferably cuboid, but can also have other shapes,

for example, have a cylindrical or pyramid shape. The pane that is permeable to ultrasound is accordingly square or round or has any polygonal shape.

In an advantageous embodiment, the edges of the ultrasound-permeable pane are beveled and sit in an undercut on the edge of the case. The bevel is usually designed so that the disc tapers outwards. However, it is a reverse bevel is also possible, in which case the disk can be glued to the edge of the housing.

The transducer is preferably located in the middle of the housing wall, that of the ultrasound-permeable disk is opposite. In this case, the transformer can be in a recess in one of the bottom of the housing wall, for example seated by adhesive bonded printed circuit board, over which the secondary connections of the transformer are passed.

The innovation is illustrated below with the aid of schematic drawings explained in more detail using exemplary embodiments.

Pig. Fig. 1 shows a plan view of an element of the vibration sensor according to the invention;

Pig. 2 shows a partial section along line II-II in Pig. 1;

Fig. 3 shows a partial section of the vibration sensor according to the innovation.

The element shown in Fig. 1 of the innovation according to the invention The vibration sensor consists of an ultrasound-permeable disc 2 on which a circular Piezoelectric ceramic disk 1 glued on. There is a recess in the pane 2 which is permeable to ultrasound provided, which is partially covered by the piezoelectric ceramic disc. From this recess 3 is a connecting line.7 led out from a solder joint (not shown in this figure) on the Underside of the piezoelectric ceramic disc 1 comes. On top of the piezoelectric ceramic disc 1 a connection line 8 with a solder connection 6 is attached.

As can be seen from FIG. 2, there is a solder connection located on the underside of the piezoelectric ceramic disk 1 in the recess 3 in the ultrasound-permeable pane 2. The gluing of the ultrasound-permeable pane Disk 2 with the piezoelectric ceramic disk 1 is indicated at 4.

As can be seen from Fig. 3, the ultrasound-permeable disk 2 with beveled edges sits firmly in an undercut which is provided on the edges 16 of a housing 15. It forms a wall this housing 15 and closes with its surface

713308 ^ 1,172

■ I J I I .11 '/ [

I 1 I. I J \ .l

II · ·, ι ι ■ Λ Λ

• '' · '· · SI Sl

it · ■ I · ··· ill ■ ft · «^ T f χ #

flush with the edges 16 of the housing. On the inside of this pane 2 which is permeable to ultrasound a piezoelectric ceramic disk 1 is attached in the aforementioned manner. On the bottom wall that the for Opposite ultrasound permeable disc, a printed circuit board 13 is attached, which has a central recess owns, in which a transformer 14 sits. The connecting cables 7 and 8 of the piezoelectric ceramic disc 1 lead to the primary connections of this transformer 14, while its secondary connections are connected to conductor tracks 11 and 12 via lines 9 and 10, c'ie on the printed circuit board, and on which the wires of a shielded cable leading to the outside (not shown) are connected.

The cavity remaining within the housing 15 is completely filled with a plastic compound which secures all elements of the vibration sensor according to the innovation in their position and against external influences, for example by moisture, heat, light etc., shields

m. 72

Claims (1)

It «ft · Protection claims; 1. Vibration sensor for alarm systems, characterized by a disc (2) which is permeable to ultrasound and which forms a wall of a housing (15) and on the inside of which a piezoelectric ceramic disc (1) sits, by a bjo in the housing (15). Another wall-mounted transmitter (1 * 0, whose primary connections are connected to the electrodes of the piezoelectric ceramic disc (1) and whose secondary connections are connected to a shielded line that is inserted into the housing (15) through a housing wall opening, and preferably through a Plastic molding compound which completely fills the remaining space in the housing (15). 2. Vibration sensor according to claim 1, characterized in that that the natural frequency of the piezoelectric ceramic disc (1) is in the ultrasonic range. 3- vibration sensor according to claim 1 or 2, characterized characterized in that the ultrasound permeable disc (2) consists of glass. ·, Vibration sensor according to one of claims 1 to 3, characterized in that the disc (2) permeable to ultrasound is one of the piezoelectric Ceramic disc (1) has partially covered recess (3) which has a solder connection (5) of the piezoelectric Lie a plumb line 7 Ή 30 8 S, 71.1.72 Picks up ceramic disc (1) and releases an öff, jag, through the one connection line (7) to this solder connection (5) leads. 5. Vibration sensor according to one of the preceding claims, characterized in that the body of the Housing (15) consists of plastic. 6. Vibration sensor according to one of the preceding claims, characterized in that the edges of the for ultrasound-permeable disc (2) bevelled -are and in a recess on a * edge of the housing (16) are stuck. 7 · Vibration sensor according to one of the preceding Claims, characterized in that the transformer (14-) sits in the cement of the housing wall, which is opposite the ultrasound-permeable pane (2). 8. Vibration sensor according to one of the preceding 'Claims, characterized in that the transformer (14) is seated in a recess in a printed circuit board (13) attached to the bottom -edtoer housing wall ' , over the dl .- * the secondary connections of the transformer (14) out.