NZ233679A

NZ233679A - Telephone handset transducer mounting

Info

Publication number: NZ233679A
Application number: NZ23367990A
Authority: NZ
Inventors: Denis Abraham; Christian Bourel; Didier Beauval
Original assignee: Alcatel Australia
Priority date: 1990-05-15
Filing date: 1990-05-15
Publication date: 1992-07-28

Description

<div class="application article clearfix" id="description"> Priority Da?c{s):..../^....... ■J 5" / . Complete . ^iuCuiv/r, fi'y'J: ..1 Ciass: {[>)../: Publication Dc.tc: .Dj.L.* P.O. Journal, h'o: NSW 2F.AIAND P.' £*NT O^CE 5 --*vy}90 CSI- NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION "TELEPHONE HANDSET" WE. SfflANDARD--TELEBHOIffiS-AN0.-CABLES-A Company of the State of New South Wales, of 252-280 Botany Road, Alexandria New South Wales 2015, Australia, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it Is to be performed, to be particularly described in and by the following statement: 1 23 3 6 7 This invention relates to a telephone handset where at least the transducer is of the piezoelectric type. Telephone handsets are usually fitted with two transducers. One transducer is used as a microphone and 5 converts the sound into electrical signals, while conversely, the other, called receiver, converts the electrical signals into sound waves. These transducers, which may be identical if of the piezoelectric type, are typically housed in individual cap-10 sules which are mounted in pairs in telephone handsets. For cost-saving purposes, it is advantageous to associate in a telephone handset an electret transducer serving as a microphone with a piezoelectric transducer acting as receiver. It is also to the manufacturer's advantage to be able to fit 15 a telephone handset with either one of the existing telephone capsules, upon the client's request, and for instance, to easily replace an electrodynamic transducer with a piezoelectric transducer, if need be. These various reasons have led manufacturers to simplify the handsets as well as 20 their assembly in order to achieve competitive prices while improving their quality and ease of operation. Therefore, the invention proposes a telephone handset in which superfluous parts have been removed, thus providing a lighter structure and accordingly, a simplified installa-25 tion. The proposed telephone handset comprises a shell having two ends. At one of these ends a microphone arrangement opens sideways and at the other end a receiver arrangement. 3oth arrangements are fitted with a transducer, at least one of these transducers being piezoelectric each transducer being housed in a part incorporating a wall through which 5 the sounds are transmitted. According to the present invention there is provided a telephone handset at the two ends of the shell of which there open sideways a microphone arrangement and a receiver arrangement respectively, both arrangements being fitted 10 with a transducer, at least one of these transducers being piezoelectric, each transducer being housed in a part incorporating a wall through which the sounds are transmitted, wherein each piece housing a piezoelectric transducer and including facilities for transducer mounting and facilities 15 for electrical connection, is assembled with at least one additional part to form the shell of the handset which it closes locally with respect to the outside, either flush mounted or protruding. The invention, its characteristics and advantages are 20 detailed in the following description, to be read in conjunction with the figures mentioned below, in which: Figure 1 shows the principle diagram of a telephone handset according to the invention, cross section partly sketched. 25 Figure 2 shows an exploded perspective of Figure 1. 3 2 3" s '/ n Figure 3 shows an exploded perspective of the connection and mounting parts for the arrangement shown in Figure 2. Figures 4 and 5 shows respectively the top view and 5 side cross-section of the fastening and connection for a telephone handset according to the invention. Figure 6 shows an exploded cross-section of an arrangement according to the invention whereby an electrodynamic transducer is substituted by a piezoelectric transducer. 10 The telephone handset partly sketched in Figure 1 is assumed to have two transducers, one operating as a microphone, the other as a receiver, and each being incorporated into a separate arrangement. Only the receiver arrangement comprising a 15 piezoelectric transducer is represented here, since the assembly of the other arrangement is either identical to that of the receiver arrangement proposed here, or typical. The microphone arrangement and the receiver arrangement of a telephone handset are housed on the same side of this 20 handset, on either side of a part (1), forming a handle, of which only the beginning has been drawn. The first arrangement comprises a microphone piece which the user places near his mouth, while the second is fitted with a receiver piece which the user holds against his ear. Only the piece (2) 25 assumed here to be the receiver has been illustrated, the corresponding piezoelectric transmitter piece would be similar . 4 2 3 3 6 7 The microphone piece and the receiver piece are assembled with at least one other piece, such as part (1), in order to form the handset shell. This shell is preferably built from one or several rigid insulating materials, it en-5 closes the other components making up the telephone handset. In the proposed embodiment, the receiver piece (2) contains the other components making up the receiver arrangement, it fits in a recess or the telephone handset shell which it closes at this level. The same applies to the 10 handset microphone piece, not shown here. Mounting of the various components making up the telephone handset shell, including the receiver piece and the microphone piece, can be carried out according to any standard procedure, for example by means of latch, electronic soldering, or glue, or 15 even by means of screws and nuts. The receiver piece (2) takes the shape of a box, at least roughly round, its base closing the telephone handset shell locally. It is designed to improve the transmission of sounds towards the user and to be comfortable when placed 20 against the ear of the user. To this end, the centre of the base of piece (2) is concave on the outside and communicates via calibrated orifices (3) with the inside of the box, thus formed by this receiver piece. Here, the orifices are recessed at the 25 level of parallel grooves (^) where the wall is thinning, as can be seen in Figure 2 where these grooves are shown in 5 -y ~r c o o "-t y cross-section, the longitudinal axis of each groove being perpendicular to the section plane- Orifices (3) lead to the centre of a cylindrical acoustic chamber (5) recessed in the box forming piece (2), be-5 tween a transducer disc and a flat inner wall of the box, which is crossed by orifices (3) and to which the disc is parallel. In a preferred design, represented in Figure 6, the inner wall, where orifices (3) are recessed, is thinner due to the presence of concentric circular grooves (31) re-10 cessed around a central hole (32) on the inner face of this wall. The transducer disc (Figure 1 and 2) comprises a circular diaphragm (6), electrically conducting, with good tensile and rigid properties to be able to vibrate for elec-15 trical signals in the 300-3000 Hz telephone band. A piezoelectric ceramics inset (7) is held by one of its sides against the diaphragm (6) to form the transducer disc; it is externally coated with an electrically conducting layer on its other side. 20 The diaphragm (6) rests by its periphery on a self- centring circular seat (8), visible in Figure 2. This seat is recessed at the extremity of chamber (5) in piece (2) in order to provide for precise positioning of the diaphragm. A fine disc (9), made of waterproof and insulating material 25 such as MYLAR is typically placed against the diaphragm (6), on the other side of the latter in relation with the inset 6 2.6 1 q (7), here being placed between the circular part (8) and this support diaphragm (6). The diaphragm (6) is held against the circular seat (8) by an assembly (10) detailed in Figures 2 to 5• The assem-5 bly (10) comprises a section (11) made of insulating material, cylindrical in appearance, which immobilises the diaphragm (6) and the disc (9), by wedging their periphery against the circular part (8) by means of a pressure tip (12) with tapered side wall, self-centered in a hollow ta-10 pered housing, complementing a cylindrical contour (13) around the circular seat (8) on piece (2), (see figures 2 and 5) • The extremity of the pressure tip (12) which comes to bear against the diaphragm, forms a ring radially crossed by 15 grooves (14) directing acoustic leaks towards a rear acoustic chamber (0), here recessed at the centre of the tip, according to a standard technique (see Figure 5). Section (11) stops and presses against the periphery of diaphragm (6) due to the action of fastening lugs (15) grab-20 bing in an internal circular groove (16) of piece (2), this groove being parallel to seat (8) in order to push section (11) towards chamber (5)- In the proposed example of implementation, four spring metal fastening lugs (15) are simultaneously made from a 25 flat blank which is first cut and bent to form a cross-shaped part, such as (17) in Figure 3- The cross-shaped part (17) is cast from a mould (not shown) filled with insu- 7 ?33679 lating hardening compound, this method allows for prccisc positioning of the various lugs (15). A portion of these lugs remains embedded in section (11). The relative positioning of a lug (15) in relation with the other lugs is initially ensured by sections (18) of cross-shaped part (17). These sections are shown in Figure 3 outside dotted circle (A), and arc removed after the compound-filling operation, once the lugs arc secured in position by the hardened compound forming scction (11). In the design illustrated, insertion of scction (II) into the open box formed by part (2). requires a centripetal compression of the spring blades making up lugs (15), the free ends of these lugs rub against the inner wall of this box until they spring away into circular groove (16). The end of each lug (15) is then braccd against the wall of this circular groove (16) such that scction (11) is pushed down the base of the box and presses against scat (8), via diaphragm (6). Selective powering up, or more precisely establishment of the electrical connection between diaphragm (6) and piezoelectric insert (7), is achieved by means of two contacts (19 and 20) respectively, these contacts having been made in the shape of independent resilient lugs, one of them resting on one of the inserts on a side of the insert opposite the diaphragm, and the other resting on the diaphragm outside the insert, as shown in Figure 1 where the position of contacts (19), (20) on the transducer disc is indicated by dashes. In the proposed implementation example, contacts (19 and 20) are achieved by catting and bending a blank made of conducting metal and in the shape of a conducting piece initially single (21) which is pressed against piece (17) before compound-filling section (11). Bending is carried out such that the contacts protrude, at an angle and In the shape of lugs, beyond pressure tip (12) when section (11) is in position, one contact then makes electrical contact with diaphragm (6) and the other with inset (7) respectively. Positioning of piece (21) in relation with piece (17) before compound-filling is ensured here by the penetration of four extensions (22, 23, 24, 25) which are bent at right angles, on the other side of the initial blank in relation with contacts (19, 20), and which penetrate into four corresponding notches (26) in piece (17). Parts (34) shown in Figure 3 outside dotted circle (B), are cut after compound-filling of section (11) over attached pieces (17 and 21). Cutting of parts (18 and 34) after compound-filling ensures the removal of electrical connection components formed by these parts between extensions (22, 24) and contact (20) on the one hand, and extensions (23, 25) and contact (19) on the other hand. It should be noted that Figure 1 Is a principle diagram and does not show the exact relative positions of lugs (15) and contacts (19> 20). In the proposed design, extensions (24, 25) protruding outside section (11) and opposite pressure tip (12), are formed to receive wire connections, with FASTON-type lugs 23 3 6 7 for instance, while extensions (22> 23) are designed to directly receive connection wires, for instance for a standard coil (not shown) designed to create, from the audio current received from the telephone line via terminals (24, 25), an 5 electromagnetic field to be used by the hearing aid of a hearing-impaired used. As indicated in the description, section (11) is compound-filled over pieces (17 and 21). Parts (18 and 34) of these pieces are removed after the compound-filling oper-10 ation in order to obtain a body, of cylindrical appearance in the proposed design, where contacts (19, 20) protrude at one end to form pressure tip (12). Here, the other end is hollow and its base contains parallel grooves (27, 28, 29, 30). 15 Grooves (27 and 29) allow extensions (22, 24 and 23, 25 respectively) to protrude into the cavity obtained in the hollow of the said other end. Implementation of a receiver or microphone piece (2) and of the telephone handset it includes is accordingly sim-20 plified. Casting of the box of piece (2), compound-filling of section (11) over pieces (17, 21) and cutting of parts (18, 34) away from these pieces are separate operations, all that remains to obtain an assembly is to stack disc (9), 25 transducer disc (6-7) and section (11) in the cavity of the box of piece (2) in the appropriate centre position, and latch lugs (15) in circular grooves (16). 10 Contacts (19 and 20) are positioned such that one contact is close to the periphery of diaphragm (6) and the other is in the central zone of the inset which is coaxial with the said diaphragm. Positioning is ensured from the 5 time the transducer disc (6-7) is correctly placed on its seat and when the pressure tip is introduced in tapered portion (13) and rests on the disc, without particular angular constraint in the cross plane. After connection of the telephone handset electric 10 wires to the extensions, namely (24, 25), assembling the telephone handset involves a simple assembly, for instance appropriate positioning and latching of piece(s) (2) with the additional part(s) of the box. The arrangement shown in Figure 6 is designed to allow 15 for substitution, as required, of an electrodynamic transducer by a piezoelectric transducer such as mentioned above. To this end, an adapter sleeve (33), here of cylindrical appearance and made up of elastomer material, is placed 20 in the housing piece (2) where a standard electrodynamic telephone capsule (34) Is to be installed, its sound transmission extremity being recessed at the end of cylindrical portion (35). One of the extremities of the adapter sleeve (33) cov-25 ers the sound transmission extremity of capsule (34) by enclosing cylindrical portion (35), such an assembly is illustrated by a dotted line in the centre area of Figure 6. 11 The other extremity of the adapter sleeve (33) is placed in the housing piece (2) in relation with the sclf-ccntring scat (8) against which it is pressed. In a preferred example of implementation, the sleeve is fitted with a circular end groove (36) which covers the cylindrical protuberance (13) by resting on circular scat 5 (8) and against the inner and outer walls of protuberance (13), as shown by a dotted line at the bottom of Figure 6, where the capsule is shown positioned. Capsule (34) is then at least partly immobilised by the pressure of the sleeve wedged between itself and the inner cylindrical wall of the housing piece. 10 15 20 25 7 APR J992.C 12 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 733679 What wc claim is:-

1. A telephone handset transducer receptacle arrangement including a transducer retaining cavity formed integrally with a first scction of the handset case, the cavity having an acoustic transmission wall which is part of the first scction of the handset case, the acoustic transmission wall including one or more through holes for acoustic transmission, the cavity having a first peripheral wall substantially perpendicular to the transmission wall, the cavity enclosing transducer mounting means including a first flat surfacc substantially parallel with the transmission wall, the first flat surface being adapted to engage the periphery of the transducer and being open over the majority of the active area of the transducer, the mounting means including a second peripheral wall tapering outwards from the first flat surfacc, the arrangement including a transducer retaining member having a peripheral projecting rim to engage the transducer opposite to the first flat surfacc, the retaining member and the first peripheral wall having co-operating resilient snap-lock arrangement to firmly retain the transducer in the cavity.

2. An arrangement as claimed in claim I, wherein the transducer is a circular piezoelectric disc, and wherein the retaining member comprises a substantially cylindrical body, the projecting rim being tapered to conform with the second peripheral wall.

3. An arrangement as claimed in claim 1 or claim 2. wherein the retaining member includes first and second resilient electrical contacts to contact corresponding elcctrical contact pads on the transducer.

4. An arrangement as claimcd in any one of claims 1 to 3. wherein the snap-lock arrangement comprises a circumfcrcntial groove on the first peripheral wall and a plurality of resilient fastening lugs projecting from the retaining member. 233679

5. An arrangement as claimed in claim 4 as appended to claim 3. wherein portions of the contacts and the lugs are embedded in the retaining member which member is made of insulating material moulded around the contacts and lugs.

6. An arrangement as claimed in claim 5, wherein the embedded portions of fas-5 tening lugs and resilient contacts arc made up of rcspcctivc first and second formed metal pieccs held against one another and in electrical contact prior to moulding; and thereafter parts of the formed metal picccs being cut off at an edge of the pieccs to electrically isolate groups of the resilient contacts and lugs from one another.

7. An arrangement as claimed in claim 3 or any one of claims 4 to 6 as appended 10 to claim 3, wherein the resilient contacts protrude from the projecting rim towards the transducer and incorporate individual connection extensions extending from the cm-bedded portions and protruding into a cavity of the retaining member located on the other side of the retaining member with respect to the contacts.

8. A telephone handset including a first arrangement as claimed in any one of 15 claims 1 to 7 and a second arrangement including a transducer retaining cavity formed integrally with a first section of the handset case, the cavity having an acoustic transmission wall which is part of the first scction of the handset case, the acoustic transmission wall including one or more through holes for acoustic transmission. the cavity having a first peripheral wall substantially perpendicular to the 20 transmission wall, the cavity enclosing transducer mounting means including a first flat surfacc substantially parallel with the transmission wall, the first flat surfacc being adapted to engage the periphery of the transducer and being open over the majority of the active area of the transducer, the mounting means including a second peripheral wall tapering outwards from the first flat surfacc. the second arrangement 25 including an adapter sleeve for an electrodynamic capsule to hold said capsulc in position in the cavity. ;2 — 233679

9. A telephone handset as claimed in claim 8. wherein the adapter sleeve is adapted to be located on a self-centring circular scat of the cavity for positioning the sleeve in the handset.

10. A telephone handset as claimed in claim 9, wherein the adapter sleeve is made 5 up of elastomer material, which incorporates a circular groove at one end for positioning the sleeve inside the self-centring circular scat of the cavity by surrounding the sccond peripheral wall and. wherein the sleeve is adapted to hold an electrodynamic capsule.

11. A telephone handset transducer rcceptacle arrangement substantially as herein 10 described with reference to the accompanying drawings. ALCATEL AUSTRALIA LIMITED 15 P.M. Conrick Authorized Agent P5/1/1703 20 25 </div>