Telephone handset chassis and flexible printed circuit

#This invention relates to a telephone handset chassis and a flexible printed circuit mounted on the chassis.

#In many forms of telephone handset, the various items such as receivers and, transmitters are mounted on a housing forming part of the handset, and then hard wired, that is connected by individual conductors attached by hand. Pushbutton dials are also mounted in handsets and again these are often first assembled to a housing or other part and then hard wired. In such arrangements, there is usually provided an assembly line along which the housing or other member passes, with different items being assembled to the housing or member at various stations. Particularly with handsets with pushbutton dials, or other forms of dial, considerable wiring has to be carried out at the assembly stage. While it is known to provide a chassis onto which the various items are assembled, the assembly then being positioned in the handset, wiring of the items on the chassis is still necessary.

#The present invention provides a sub-assembly for a telephone handset in which the interconnections are made by a flexible printed circuit, and in which certain items are preassembled to the flexible circuit member. At least some of these items, which are assembled on to the flexible circuit member, snap into position on the chassis while other items are first snapped into position and then parts of the flexible circuit are connected to these items. The flexible circuit member carries the pushbutton dial assembly and the flexible circuit member passes through the chassis with the part carrying the dial being on one side, for example, the front side of the chassis, while the other part of the circuit being on the other side, for example the rear side.

#The invention will be readily understood by the following description of an embodiment, by way of example, in conjunction with the accompanying drawings, in which:

#FIG. 1 is a perspective view on the back side of a chassis;

#FIG. 2 is a longitudinal cross-section on the line II--II of FIG. 1;

#As illustrated in FIG. 1, a chassis 10 is in the form of an elongate flat member, generally of molded plastic material, and having a mounting position 11 at one end for reception of a transmitter, not shown in FIG. 1. As illustrated in FIG. 1, the back side 12 of the chassis is uppermost. The chassis has three sections 13, 14 and 15, end section 13 at one end having a mounting position 16 for a receiver, in the present example an electret receiver, and a clip-in position 17 for a recall switch. End section 15 at the other end contains the mounting position 11, in the form of an aperture, for the transmitter. The intermediate or central section 14 is adapted for mounting of the pushbutton switch or dial assembly. In the example, the receiver and recall switch are mounted from the rear side of the chassis, the transmitter is entered from the front side, and clips in, and the pushbutton dial also mounts on the front side. A transverse slot 18 extends through the chassis at one end of the center section 14, adjacent to the end section 15. Section 13 also has an extension 19 on which is mounted a jack, not shown in FIG. 1, for reception of the plug on the end of the handset cord.

#FIG. 2 illustrates the relative inclinations of the sections 13, 14 and 15. The sections are inclined to give the overall arcuate effect as required by the handset to suit the facial characteristics of a user. Making the three sections as three somewhat planar sections is more convenient for manufacturing purposes, but sections 13 and 15 could be arcuate if desired. Also seen are the positions 11, 16, 17 and 19. FIGS. 3, 4 and 5 show the back sides 12 of the various sections of the chassis. Also seen in FIGS. 1 and 2 are resilient members 20 which retain the transmitter in position. Two members 20 are provided, at the positions indicated in FIG. 5. The members deflect outwards as the transmitter is pushed into the aperture at 11 and engage over the front edge of the transmitter. The rear of the transmitter abuts a radially inward extending rim 21 on the back side of section 14. Various holes are provided through the chassis for assembly to the handset housings, as will be seen in FIGS. 6 and 9.

#FIG. 6 shows the various components which form an assembled chassis. A flexible circuit member 25 is shown, which comprises two main parts, part 25a which carries the circuit 26 on a back surface for various electronic components, not seen, mounted on a front surface, and also has mounted thereon the receiver 27 and the recall button 28. The electronic components, receiver and recall button are mounted on the front surface of part 25a and can be flow soldered to the circuit 26. Also attached and connected to part 25a is jack 29 for the handset cord plug (not shown), the jack, in the present example, being connected via conductors 30, although by suitably redesigning the jack 29, this could be mounted on an extension of the part 25a.