Piezoceramic capsule for telephone instruments
AssigneeAlcatel Dial Face S.p.A.
InventorsAntonio D'Avolio, Luigi Pesenti
Life of this patent
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Abstract
A piezoceramic capsule for telephone instruments, of the type comprising a terminal-holder spool, a piezoceramic diaphragm in pressure contact with nail-shaped feed-through terminals forced in the spool, an elastic O-ring for producing the contact pressure and a perforated case housing them, is modified to transform the case into a cover-up disc and the spool into a case being provided with a stepped cylindric cavity designed to house, from the bottom to the top, respectively, the diaphragm, the elastic O-ring and the cover-up disc. A plurality of resilient pawls are formed by pressing inside respective cuts provided in the sidewall of the opening of said cylindric cavity and designed to snap on said cover-up disc in a closure position.
Claims8
Piezoceramic capsule for telephone instruments, comprising:
- a base in the form of a circular spool made of insulating material, provided with at least two nail-shaped feed-through terminals, forced into respective through-holes axially extending in said base, said terminals being accessible from outside said base;
- a piezoceramic diaphragm in the form of a disc having a central portion of a first face covered by a circular ceramic layer and having two poles located on said first face to be in pressure contact with heads of said two nail-shaped terminals respectively;
- an elastic element in a form of an O-ring disposed on a second face of said diaphragm for providing a selected contact pressure between said poles and said terminal heads;
- and
- a case provided with at least one opening for the transmission of acoustic waves generated by vibrations of said diaphragm, disposed in such a way as to hold said elastic element in contact with said diaphragm;
- said case being substantially formed as a cover-up disc;
- said circular spool has a cylindrical cavity hollowed out therein to house from inside to outside in an assembly order comprising, respectively, said diaphragm, said O-ring and said cover-up disc and to hold said diaphragm, said O-ring and said cover-up disc assembled with a selected pre-loading on the O-ring;
- and
- a portion of said circular spool between an outer perimeter thereof and an inner wall of an intermediate section of said cylindrical cavity being broken by a plurality of radial cuts axially extending beyond an innermost cavity section, a plurality of resilient pawls are arranged inside each of said plurality of radial cuts, each of said resilient pawls being movable in a radial direction for snapping on an outer surface of said cover-up disc and for holding said diaphragm, said O-ring and said cover-up disc assembled with said selected pre-loading on said O-ring.
Dependencies are inferred from the claim text.