Method for initially polarizing and centering a piezoelectric ceramic switching device

Abstract

Improved piezoelectric ceramic switching devices are described along with their method methods of fabrication. In addition to the devices themselves, novel electric circuits are described for the energization as well as the use of such devices as switching elements in electrical systems. Parts of both the energization circuits and/or utilization circuits employing the piezo ceramic switching device are physically mounted on and supported by non-polarized parts of the piezoelectric ceramic plate elements comprising the switching devices so that lightweight compact construction is achieved along with substantial reduction of stray inductance intercoupling.

Description

This is a division, of copending application Ser. No. 685,109, filed Dec. 21, 1984 now thebestportions capacitorusefullness usefulness with minaturized miniaturized circuit components is greatly improved. Further, because the circuit components with which the devices are used can be mounted right on a portion of the devices themselves, stray circuit inductance is greatly reduced thereby improving the circuit noise immunity characteristics during operation of the devices

The piezoelectric ceramic switching devices fabricated in accordance with the invention are of greatly improved construction and opeating characteristics than the comparable prior art devices of the same general nature. The improved piezoceramic switching devices consequently operate with greater stability, reliability and longetivity in service over extended periods of operation requiring substantial numbers of switching operations.

INDUSTRIAL APPLICABILITY

Improved piezoelectric ceramic switching devices and systems having the features of construction made available by the invention are useful in a wide number of residential, commercial and heavy industrial electrical systems for use as switching devices in controlling current flow to widely different types of electrical loads having different power ratings. Because of their novel construction, the devices are of lighter weight, less bulk and lower cost than comparable electromagnetically operated switching devices currently being used and have much faster response times.

Having described several embodiments of new and improved piezoelectric ceramic switching devices and systems using the same and their methods of manufacture in accordance with the invention, it is believed obvious that other modifications and variations of the invention will be suggested to those skilled in the art in the light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims.

Claims

1. The method of prepolarizing and centering the movable piezoceramic bender member of a piezoceramic bender-type switching device which comprises substantially completing the fabrication assembly of all of the major components of the piezoceramic switching device into a unitary structure and thereafter applying a relatively high value prepolarization potential to the respective piezoceramic plate elements of the bender member while maintaining the plate elements near their Curie temperature to achieve dipole alignment of the dipoles of the piezoceramic material and thereafter simultaneously adjusting the relative magnitudes of the prepolarizing potential applied to the respective piezoceramic plate elements of the bender member to cause it to be precisely positioned relative to the load current fixed switch contacts of the switching device.

2. The method of prepolarizing and centering the movable piezoceramic bender member of a piezoceramic bender-type switching device which comprises substantially completing the fabrication assembly of all of the major components of the piezoceramic switching device into a unitary structure and thereafter applying a relatively high value prepolarization potential to the respective piezoceramic plate elements of the bender member to achieve dipole alignment of the dipoles of the piezoceramic material and thereafter simultaneously adjusting the relative magnitudes of the prepolarizing potential applied to the respective piezoceramic plate elements of the bender member to cause it to be precisely positioned relative to the load current fixed switch contacts of the switching device.

3. A method for initially polarizing and controlling the movement of a piezoceramic bender-type switching device having a movable piezoceramic bender member comprised by at least two planar piezoceramic plate elements, the piezoceramic bender-type switching device including at least one set of coacting electrical switch contacts opened and closed by the movable bender member of the piezoceramic switching device, and clamping means securing the piezoceramic plate elements together and mechanically supporting the movable bender member in a cantilever manner for opening and closing the set of coacting electrical switch contacts comprising the steps of:

(a) connecting the piezoceramic bender-type switching device to a power source with selectively operable electrical excitation circuit means, whereby a direct current energizing potential is selectively applied to each piezoceramic plate element, causing initial polarization of the plate elements,

(b) thereafter adjusting the relative magnitudes of the initial polarization potentials applied to the respective plate elements to cause the bender member to be precisely positioned relative to the switch contacts, and

(c) subsequently applying direct current energizing potential from the power source to the polarized piezoceramic plate elements only in the same direction employed to initially polarize the respective plate elements. 4. The method of claim 3 wherein the initial polarization in each piezoceramic plate element is produced at an energizing potential level exceeding the energizing potential level of the power source. 5. The method of claim 3 wherein an end portion of each polarized piezoceramic plate element remains unpolarized.

. A method of initially polarizing and centering the movable piezoceramic bender member of a piezoceramic bender-type switching device, comprising:

substantially completing the assembly of all of the major components of the piezoceramic switching device into a unitary structure;

applying a relatively high value initial polarization potential to the respective piezoceramic plate elements of the bender member to achieve dipole alignment of the piezoceramic material; and

simultaneously adjusting the relative magnitudes of the initial polarizing potential applied to the respective piezoceramic plate elements of the bender member to cause it to be precisely positioned relative to the load

current fixed switch contacts of the switching device. 7. The method of claim 7 wherein the bender member further includes two sets of coacting electrical switch contacts disposed on opposite sides of the bender member, further including the step of applying the energizing potential in a manner which enables make or break connection of electric current to at least two separate electrically conductive paths extending through the respective sets of contacts. 8. The method of claim 3 further including preventing excess arcing across the coacting electrical contacts when opened to interrupt electrical current being applied through a load. 9. The method of claim 3 further including causing the set of coacting electrical switch contacts to close upon the application of the direct current energizing potential. 10. The method of claim 9 further including causing the set of switch contacts to open upon the removal of the energizing potential.