US2210045A

US2210045A - Piezo-electric crystal holder

Info

Publication number: US2210045A
Application number: US235928A
Authority: US
Inventors: Schneider Wilhelm
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1937-10-30
Filing date: 1938-10-20
Publication date: 1940-08-06
Anticipated expiration: 1957-08-06

Description

g- 1940- w. SCHNEIDER PIEZO-ELECTRIC CRYSTAL HOLDER Filed Oct. 20, 1938 QUARTZ CRYSTAL Y mmgm T5 .W M A Patented Aug. 6, 1940 UNITED STATES PATENT OFFWE PIEZO-ELECTRIO CRYSTAL HOLDER.

tion of Germany Application October 20, 1933, Serial No. 235,928 In Germany October 30, 1937 7 Claims.

This invention relates to a novel supporting or mounting for piezoelectric oscillator crystals. It concerns more particularly the mode of accommodating two crystals inside a minimum amount of space. An arrangement of this kind is useful to particularly great advantage in heterodyne sets in which two piezoelectric crystals are to oscillate at different frequencies in such a way as to result in as stable as feasible a frequency difference. In order to secure a steady and stable frequency difference it is advantageous to mount the two crystals under similar conditions and at the greatest possible proximity to each other, while taking care so that they are subject to the identical external conditions as to temperature, etc.

The object of the invention satisfies these requirements, while it solves at the same time the problem of holding or mounting the crystals inside a minimum space.

A feature of this invention is a twin crystal mounted in a case comprising two ceramic cups or shells comprising a central electrode common to both oscillator crystals and adjustable external electrodes.

The invention shall be described more fully by reference to the appended drawing. The single.

figure is a sectional view of an embodiment of my invention. The ceramic cups or shells I support the electrodes 3 adjustably held in the bushes or sleeves 2. The central electrode 4 has a peripheral enlargement 5 of annular form, and the inner circumference thereof has screw-threads cut therein upon both sides. Screwed into these screw-threads are the supporting rings 6; by the aid of clamp screws 7 they may be locked in a definite position. In the holder rings 6 are held the quartz crystals 8 by the agency of screws 9. By rotation of the said holder rings in their screw-threads they may be looked a certain distance from the central electrode. The outer parts of the mounting l, 2 and 3 referred to above are secured by screws iii on the holder rings 6, and this insures a stable and dependable union and assembly of all constituent parts.

A special merit of the invention as described is that the oscillation crystals individually are settable in reference to the central electrode, as well as that the outer electrodes are adjustable individually without it being necessary to demount the device to this end. In fact, to set the crystals in relation to the central electrode all that is necessary is to loosen the clamp screw 1 in order to allow turning the entire top part comprising crystal, holder rings, ceramic shells and external electrode whereby the distance between the crystal and the median electrode is altered. The adjustment of the outer electrodes 3 is effected by rotation of the screw-threads of bushes 2. It will thus be noted that the setting of the inter-electrode 5 distances is feasible under conditions independent of each other, without incidentally the adjustment of one electrode distance affecting that of the other in any way.

It will be understood that in lieu of an arrange- 10 ment comprising holder rings being adjustable in reference to the central electrode it is also possible to resort to a simplified embodiment in which the holder rings are fitted firmly upon the median electrode and are screwed together therewith. 16

What is claimed is:

1. Holder or mounting for two piezoelectric vibratory or oscillatory crystals, with the characteristic feature that a central electrode common to both quartz crystals is provided which has an an- 20 nular enlargement in which are screwed the rings serving for holding the quartz.

2. Twin crystal mounting or holder as claimed in claim 1, with the characteristic feature that the distance between each of the crystals and the 25 middle electrode is individually and separately adjustable by rotation of the crystal mounting ring in the screw-thread of the middle electrode.

3. Twin-crystal mounting or holder as claimed in claim 1, with the characteristic feature that 30 held on the crystal holder ring by means of screws upon each side thereof is a ceramic half-shell or cup in which the outer electrode is adjustably mounted.

4. A holder for a pair of piezoelectric crystals 35 comprising a central electrode having an annular rim, crystal holding rings in individual adjustable relationship with said rim whereby the spacing between said central electrode and each of the crystals carried by said rings may be independently adjusted, insulating cups carried by each of said rings and outer electrodes adjustably carried by said cups.

5. A holder for a pair of piezoelectric crystals comprising a central electrode having an annular 45 rim, said rim being screw-threaded on its inner surface, crystal holder rings in threaded engagement with said rings, said rings being individually adjustable along said rim whereby the spacing between said central electrode and each of the crystals carried by said rings may be independently adjusted, insulating cups carried by each of said rings and outer electrodes adjustably carried by said cups.

6. A holder for a pair of piezoelectric crystals comprising a central electrode having an annular rim, said rim being screw-threaded on its inner surface, crystal hold-er ringsin threaded engagement with said rings, said rings being individually adjustable along said rim whereby the spacing between said central electrode and each of the crystals carried by said rings may be independently adjusted, insulating cups carried by each of said rings and outer electrodes within each of said cups and threaded means for varying the spacing between each of said crystals and its adjustable outer electrode.

7. A holder for a pair of piezoelectric crystals comp-rising a central electrode having an annular rim, said rim being screw-threaded on its in ner surface, crystal holder rings in threaded engagement with said rings, said rings being individ ually adjustable along said rim whereby the spacing between said central electrode and each of the crystals carried by said rings may be independently adjusted, insulating cups carried by each of said rings, a threaded bushing in each of said cups and outer electrodes having threaded shanks engaged in said bushings whereby each of said outer electrodes may be adjustably positioned with respect to its adjacent crystal.

TlLI-IELM SCHNEIDER.