Ericsson DIALOG - Instrument Case

Fig. 15 a Th e dial unit-rear view
Fig.
1 6
3.5 Inst rume nt case
Fig. 15 b The dial unit-front view
The dial mechanism is the same as in L M Ericsson's previous
telephone instruments and is guaranteed for an average of one
million operations, which, for six-digit numbers, corresponds to
18 dialled calls per day for 25 years.
The dial speed is easy to adjust by means of a screw-driver.
The rim of the impulse cams is domed to provide a perfect sliding
surface for the impulse springs. The impulse cams are thus
protected against damage from the edges of the springs. The
impulse wheel is made of nylon. Owing to the low friction of nylon,
no
lubrication is necessary.
The thermoplastic material used in the instrument case (fig. 17)
gives a smooth. colour-fast surface, which has good resistan ce
to impact and is not easily scratched. It is not affected by
perspiration , skin creams, and lipstick. The material has good
ageing properties. Water and soap will remove almost any stain.
The instrument cradle is designed so that the handset , even if
carelessly replaced. always falls into the correct rest position.
Fig , 17
The instru-
me nt case
13
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