US 3566164 A
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United States Patent Pierre Boillat Neuchatel;
Richard Challandes, Sonceboz, Switzerland 749,240
May 31, 1968 Feb. 23, 197 1 Centre Electronique Horloger S.A. Neuchatel, Switzerland June 5, 1967 Switzerland lnventors Appl. No. Filed Patented Assignee Priority SYSTEM FOR RESILIENTLY SUPPORTING AN OSCILLATION QUARTZ IN A CASING 4 Claims, 7 Drawing Figs.
US. Cl 3l0/9.l Int. Cl. H01v 7/00 Field ofSearch 310/8.l,
References Cited UNITED STATES PATENTS 4/1958 Potter m Primary Examiner-Milton O. Hirshfield Assistant Examiner-B. A. Reynolds Attorney-Stevens, Davis, Miller & Mosher ABSTRACT: This invention'involves the resilient suspension of a quartz oscillator in a casing. Resilient suspension members are provided between the nodal joints of the quartz and the casing and damping members are disposed so as to damp and limit the displacement of the quartz under conditions of shock.
piezoelectric crystal resonator.
SYSTEM FOR RESILIENTLY SUPPORTING AN OSCILLA'IION QUARTZ IN A CASING The present invention concerns a resiliently suspended The purpose of the invention is to prevent the limit of elasticity of the suspension from being exceeded.
The resonator is characterized in that it comprises at least one shock absorber whichlimits the displacement of the crystal under the influence of shocks, in a zone contained in the zone of elasticity of the suspension of the crystal.
The drawing illustrates a known resonator and, by way of examples, two embodiments of the resonator according to the invention. v
FIG. 1 is a perspective view of a quartz resonator showing the position of the nodal points. i
FIG. 2 is a diagrammatic view showing the mode of oscillation of the quartz.
FIG. 3 is a diagrammatic cross-sectional view showing how a quartz is mounted in a capsule, according to a known device.
FIG. 4 is a partial cross-sectional large scale view aiong 4-4 in FIG. 5, of a first embodiment.
. FIG. 5 is a partial view in elevation with part of the capsule cut away.
FIG. 6 is a partial crosssectional large scale view along 6-6 in FIG. 7, of a second embodiment.
FIG. 7 is a partial'cross-sectional view along 7-7 in FIG. 6. FIG. I shows a quartz rod 1", having the length L, which is free at both ends. When it oscillates in the fundamental mode and in flexion XY, two nodalpoints P, P are found which are situated a't a distance 0.224 L from the corresponding -ends, these two nodal points being separated by a distance 1-.
According to the known device illustrated in FIGS, the rod 1 is mounted in a capsule 2 by means of four springs 3, secured at one end to one of the nodal points of the quartz and at the other end, to a cross piece 4, which is insulated in 5 from the capsule 2.
When the quartz vibrates with the frequency f, the points of attachment P,P are subjected to arotation, as shown in FIG.
2, and the distance separating them is periodically shortened with a frequency which is double the frequency f of the quartz.
It is therefore necessary to provide a resilient suspension device which is such that the deformations imposed by the deformations of the quartz as indicated above, do not cause losses which would be incompatible with the'high factor of quality characterizing quartz resonators.
The mechanical characteristics of such a suspension device do not enable it to absorb high accelerations and cannot prevent the quartz from coming into contact with the capsule, which is of small dimensions (compatible with those of a watch).
The two embodiments described below make it possible:
a. to prevent the suspension device fromexceeding its limit of elasticity;
b. to prevent the quartz from coming into contact with the capsule and thus be chipped orbroken;
c. to deaden the effect of shocks and limit the displacements of the quartz in its capsule by acting at the nodal points, in order that the vibration of the quartz may suffer the least possible interference d. to avoid short-circuiting two electric poles of the quartz or one pole with the capsule when the damping device intervenes.
FIGS. 4-and 5 illustrate the suspension of the quartz in one of its nodal axes P-'-P. g
The quartz I0 is secured to the capsule 11 by means of two the spring I4 is integral with a flat flange 22, of a generally circular shape, the spring [4 and the flange 22 being situated in the same plane. The resilience of the spring is such that the quartz is enabled to vibrate correctly without this spring introducing losses which would be incompatible with those of the quartz.
The suspension members 12 and 13 are each also provided with a protecting member such as spring 16, constituted by an inclined arm 17 the free end of which ends in a circular part 18 partially surrounding the wire 15. This circular part is situated in a plane which is parallel to the flange 22 and to the quartz 10. The flanges 22 of each of the suspension members l2, 13 are respectively welded to a rod 19 made of Kovar, the rod passes through the capsule 11 through a glass ring 20 secured in a fluid-tight manner to the capsule II by means of a sleeve 21.
In the case of shocks or accelerations exceeding certain values which the suspension spring 14 are unable to absorb, the wires 15 or the quartz 10 will come into contact with the part 18 of the protecting springs 16 of lower elasticity which will absorb the shocks thus preventing thequartz from coming into contact with the capsule .11.
The suspension members l2, 13 being in one piece are everywhere at the same voltage, which suppresses the necessi- 'ty of particular insulation in order to avoid a short circuit.
It may be remarked that owing to the fact that shocks are absorbed at nodal points they only cause a trifling perturbation of the mode of oscillation of the quartz.
suspension members 12 and 13, arranged on either side of the quartz 10, two other identical members being provided at the other nodal axis. a
The suspension members 12,13 each comprise a resilient means such as suspension spring 14 the free end of which is welded to one end of a wire 15-, the other end of which is welded to the nodal point of the quartz 10. The other-end of The rigidity of each of the" protecting springs 16 will be greater than the rigidity of the assembly of suspension springs 14.
FIGS. 6 and 7 are FIGS; corresponding to FIGS. '4 and 5 and illustrate the suspension of the quartz in one of the nodal axes P-P.
The quartz 30 is secured to the capsule 31 by two suspension members 32 and 33 disposed on-either side of the quartz 30, two other identical members being provided at the other nodal axis.
Each of these suspension members comprises a suspension element or wire 34 one end of which is wound around a corresponding damping element or wire 35 to which it is welded, one of the ends of this wire being secured to the corresponding nodal point of the quartz 30. The other end of the suspension wire 34 is secured to the inner end of a transverse Kovar rod 36 which is held by a glass ring 37 secured to the capsule 31 by means of a sleeve 38, secured in a fluid-tight manner to the capsule 31. The free end of the wire 35 cooperates with an annular stop 39 and with an axial stop 40 constituted by watch jewels. These stops 39 and 40 are held in spaced relation by means of a washer 41 in a hollow support 42. It may be seen that the wires 35, which are less resilient than the wires 34, have a certain clearance in relation to the stops 39 and 40, which are insulated from the capsule 31. When shocks occur, the quartz will be limited in its displacements by the stops coming into contact with the damping wires 35.
It is obvious that in the two preceding embodiments, the capsule 11 or 31 could be replaced by a support.
I. A resonator device, comprising a casing, a quartz crystal oscillator, a plurality of resilient members for holding said oscillator for free oscillation in said casing, and a plurality of damping means for limiting the displacement of said oscillator within said casing under the influence of shocks, each resilient member being fixed at one end to a pin located in the wall of said casing, and at the other end to a second pin soldered toa nodal point of said oscillator, each second pin extending from the corresponding nodal point along the corresponding nodal axis; and each of said damping means including a rigid end fixed to said casing and a resilient end surrounding said second pin, the stiffness of said resilient end being greater than the stiffness of each of said resilient members.
2. A resonator device according to claim I wherein four resilient members and four damping means are used.
dered to a nodal point of said oscillator, each second pin extending from the corresponding nodal point along the corresponding nodal axis, and each of said damping means comprising an annular stop and an axial stop for each second pin.
4. A resonator device according to claim 3 wherein four resilient members and four damping means are used.