DE1068358B - Electric wobble device, especially for ultrasonic devices ^ - Google Patents

Description

There are numerous constructions of frequency converters known, d. H. of facilities to determine the fundamental and natural frequency of an oscillatory circuit to change alternately. Particularly in the field of ultrasonic technology, one often makes use of it Transmitter whose frequency is changed, the frequency conversion generally being in the range moved from 20 to SO Hertz.

A relatively simple design for frequency conversion of a generator in the one mentioned Frequency range consists in using a vibrator with a part made of magnetic material, which alternately approaches the coil of an oscillating circuit of the generator and again away from her. If you use such devices in devices that are used for thickness measurement or for Serve detection of errors with the help of ultrasound, then there are disadvantages that these vibrators in general, be it in terms of frequency or in terms of vibration amplitude, do not have sufficient stability. This also applies to the well-known alternating current generators, in which the required change in the self-induction of the oscillation circuit by the arrangement of a rotor with spatially periodically distributed electrical conductivity in the field of a number a disc near the periphery of which is arranged coils. In addition, one can with such a Device also only change the speed of the rotor, so that the frequency of the inductance fluctuations is about twice as large as the natural frequency of the connected oscillating circuit. Of the The oscillating circuit then excites itself, and the required alternating current is generated in it generated with this one desired frequency.

An inductor machine with permanent magnets has also become known, in which the change in the lines of force in the coils attached to the magnets is effected by connecting pieces, which are evenly distributed in a non- +0 magnetic disc rotating between the magnetic poles, whereby for generation a magnetic shunt to the induced coils, a second row of tail pieces can be arranged on the disc. The frequency of ER testified alternating currents depends therefore on the number of iron trailer tracks on the rotating disk. However, since this arrangement does not have a resonant circuit with a capacitor and self-induction coil with variable inductance, the frequency cannot be changed during operation, because the number of iron terminal pieces cannot be changed while the disk is rotating.

The invention is based on this prior art electrical wobble device,
especially for ultrasound devices

Applicant:

Holding Electrosonic SA,
Friborg (Switzerland)

Representative: Dr.-Ing. F. Mayer, patent attorney,
Berlin-Dahlem, Hüttenweg 15

Claimed priority:
Switzerland from April 13, 1956

Roger Legrand, Geneva (Switzerland),
has been named as the inventor

and consists essentially in the fact that in place of a transmitter with a fixed frequency an electrical wobble device is set, as it is known per se from communications engineering. It is characterized by an oscillating circuit with an induction coil on a magnetic one Core is applied, and a known arrangement of a rotating disk with individual on this arranged pieces of ferromagnetic material, which are so distributed on the disk are that they pass the core one after the other as they rotate, the disk being more known per se Way is driven by the interposition of a friction wheel, the speed of the disc by Change in the distance of the friction wheel from the axis of the disc is adjustable and the distance of the Disc can be changed from the core.

In a preferred embodiment of the subject matter of the invention, the magnetic core has Shape of a pot, and the magnetic pieces have the same diameter as this pot.

The drawing shows, schematically and by way of example, an embodiment of the electric wobble device shown according to the invention.

Fig. 1 shows in side view and

2 shows the new device in plan view.

On a base plate 1 bearing blocks 2 and 3 for a shaft 4 are attached, which as a rotatable member a disk 5 carries. The disc can be essentially

909 647/175

Claims (2)

Union constant speed are driven by an electric motor 6, which acts via a reduction gear 7 on a rubber-coated friction wheel 8. The motor 6 is held by means of a screw 9 and a clamp 10 fastened to the bearing block 3. It rotates at a constant speed, whereby the desired speed of the disk 5 can be adjusted by changing the position of the unit 6, 7, 8 and thus varying the distance between the friction wheel 8 and the shaft 4. Another support 11, which has a non-circular bore 12, is seated on the base plate 1. A threaded bolt 13 with a corresponding cross-section can be displaced in the said bore and, at its end facing the disk 5, has an attachment 14 made of agglomerated iron, which forms the magnetic core of a coil indicated at 15. This coil together with the capacitor 16 represents the oscillation circuit of an ultrasonic generator. A screw nut 17 with a knurled edge, which sits on the bolt 13 in an incision in the support 11, allows the axial adjustment of the bolt 13. The disk 5 carries six to the pot like approach 14 matching "cover" 18, which are made of magnetic material and are usually composed of agglomerated iron. As the disc 5 rotates, the elements 18 pass one by one past the core 14 so that the inductance of the coil 15 is changed periodically. However, this results in a periodic change in the fundamental frequency of the oscillating circuit of the generator, that is, a wobble in the frequency. The periodicity of the wobble is determined by the speed of rotation of the disk 5 and by the number of pieces 18 carried by it. The amplitude of the wobble, i.e. H. the distance between the maximum and minimum frequencies of the oscillating circuit depends on the inductance of the coil 15 and can be changed by adjusting the magnetic core 14 closer or further away from the pieces 18 by means of the screw 17. The device described is of a very simple design and has great stability, so that it can be used particularly advantageously for portable generators which are exposed to more or less strong vibrations during use. Naturally, this level of stability could also be achieved with other constructive solutions such as the one shown by way of example, provided that only a rotatable member is used, which is driven by a motor at a constant speed, and at least one element made of magnetic material is attached to it in such a way that it periodically moves past a coil. The changes in inductance of the coil are greater when the coil has a magnetic core. In addition, it could be useful for certain portable devices to replace the electric motor with a spring motor. Patent claims: 1. Electrical wobbling device, characterized by an oscillating circuit (15, 16) with an induction coil (15) which is applied to a magnetic core (14), and a known arrangement consisting of a rotating disc (5) with individual ones arranged on it Pieces (18) made of ferromagnetic material, which are distributed on the disc, that they pass the core (14) one after the other as they rotate, the disk in at is driven in a known manner by the interposition of a friction wheel (8), the speed the disc (5) can be regulated by changing the distance between the friction wheel and the axis of the disc and the distance between the disc (5) and the core (14) can be changed. 2. Apparatus according to claim 1, characterized in that the magnetic core (14) the Has the shape of a pot and the magnetic pieces (18) have the same diameter as this Have pot. Considered publications:
German patent specifications No. 633 258, 157 152. 1 sheet of drawings »909 647/175 10.59