HOOK SWITCH FOR A TELEPHONE INSTRUMENT OF SINGLE BODY TYPE

COMMUTATEUR POUR TELEPHONE MONOBLOC

English Abstract

ABSTRACT OF THE DISCLOSURE
A hook switch arrangement for a telephone instrument
of the single body type comprises actuating means protruding
through the bottom surface of the instrument to actuate the
hook switch of the instrument by means of a support on which the
instrument is placed after a call. The actuating means cooper-
ate with elements actuating the springs of the hook switch. The
elements comprising rods provided with arms to convert the move-
ment of the actuating means to rotating movement and a spring
actuated rack member engaging a pinion, which on rotation actuates
the hook switch. The rods are provided with further arms which
on rotation displace the rack member.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a telephone instrument of the single-body type
having a hook switch and a bottom surface, an arrangement for ac-
tuating the hook switch comprising displaceable members pro-
truding from said bottom surface and arranged so as to be pushed
into the instrument when it is placed on a support surface, rods
provided with arms cooperating with said protruding members to
convert the displacement of the protruding members into a
rotary movement of said rods, a spring-biased rack member dis-
placeable by further arms on said rods against -the action of said
spring when said rods are rotated, and a pinion engaging said
rack member and actuating the hook switch when the rack member
is displaced by at least one of said further arms.
2. A telephone instrument according to claim 1,
wherein the rack member comprises a support bar and a rack adjus-
table relative to the support bar, said rack being located on
the support bar by means of eccentric cams engaging oblong holes
in the rack, whereby the rack is displaceable transversally and
longitudinally on the support bar to enable the clearance be-
tween the teeth of the rack and pinion, and contact operation
of the switch to be adjusted.
3. A telephone instrument according to claim 1, compri-
sing two said rods, are. at each end of said rack member, the
further arm of each said rod cooperating with a respective abut-
ment on the rack member, said further arms being on the same
side of their respective abutments so that rotation of one of
said rods displaces said rack member but does not cause rotation
of the other of said rods.
4. A telephone instrument according to claim 3, compri-
sing the rods are arranged so that depression of their associated
protruding members causes them to rotate in opposite senses.
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Description

This invention relates to a -telephone ins-trument of the
sin~le bo~y type, comprising actuating means protruding -through
its bottom surface for actuating a hook switch by means of a
support on which the instrument is placed after a call. The
actuating means cornprises members distributed along the peri-
phery oE the bottom surface, each member cooperating with elements
actuating springs of the hook switch. By hook switch is meant
the switch in the telephone instrument for holding the line to
the exchange and thereby enabling a telephone conversation to take place.
Arrangements of the mentioned type are previously known,
for example, from U.S. Patent No. 3,562,447, and are particularly
effective when it is desired to guarantee a correct hook switch
~unction in the case of an uneven support.
The known arrangement comprising two longitudinally dis-
placeable arms which through their displacement actuate a rotat-
able contact element has the disadvantage that the force required
to actuate the contact elements is relatively large at the begin-
ning of their movement and smallest in the middle of -their
movement when the contact element, consisting of a rotatable arm,
is perpendicular to the direc-tion of the displaceable arms. In
unfavourable cases, locking can occur such that the return spring
cannot bring the contact element back to its rest position.
An object of the invention is to provide a hook switch
function with an even and relatively low operating power. With
the arrangement according to the invention easier adjustment,
easier mounting, and elimination of the risk of self-locking is
also achieved.
According -to the present invention there is provided in
a telephone instrument of the single-body type having a hook
switch and a bottom surface, an arrangement for actuating the hook
switch compirsing displaceable members protruding from said bot-
tom surface and arranged so as to be pushed into the instrument

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when it is placed on a support surface, rods provided with arms
cooperating with said protruding members to convert the displace-
ment of the protruding members into a rotary movement of said
rods, a spring-biased rack member displaceable by further arms
on said rods against the action of said spring when said rods
are rotated, and a pinion engaging said rack member and actuating
the hook switch when the rack member is displaced by at least
one of said further arms.
The invention will now be described in more detail, by
way of example only, with reference to the accompanying drawings,
in which:-
Figure 1 is an exploded view of a hook switch arrange-
ment according to the invention; and
Figure 2 is a side view of a rack-and-pinion forming
part of the arrangement.
In Figure 1 only those parts of a telephone instrument
: necessary to explain the idea of the invention have been shown,
while other parts have been omitted.
The hook switch arrangemellt has a long actuating means
~ 10 and two shorter actuating means 11 and 12, which, in a tele-
phone instrument of single-body type, for example, the telephone
instrument EPRICOFON T~, protrude through the bottom surface of
the instrument (not shown in the drawing) and are pushed into
the instrument when it is placed on a support. They then actu-
ate elements which in their turn actuate contact springs in
the contact device of the instrument. The elements comprise
rods 13,14, which are rotatable by the actuating means, and a
rack arrangement 15, which is displaceable in the longi-tudinal
. direction by the rotation of at least one of said rods. The
30 rack arrangement 15 has an adjustable rack ~ cooperating with
a pinion 16 on the camshaft of a camshaft controlled relay 17.
Tlle rod 13 cooperates with the actuating means 10, and the rod 1

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cooperates with -the actuating means 11 and 12, with the aid of
arms 20 which are turned when the respective actuating means is
displaced vertically. The rods 13,14 are at one of their ends
provided with a further arm 21, which on rota-tion of the rod dis-
places the rack arrangement in the longitudinal direction against
the force of a spring 18. The rods 13,14 are arranged in such
a way that the rack arrangement 15 is actuated regardless of
whether only one or all of the actuating means are depressed.
As appears from -the drawing, the arm 21 of the rod 13 is turned
anti-clockwise when the actuating means 10 is pushed inwards
and by means of the projection 22 displaces the rack arrangement
against the force of the spring 18. If only one of the actuating
means 11. or 12 is pushed inwards, the arm 21 on the rod 14 is
turned clockwise and by means of the projection~23 displaces
the rack arrangement against the force of -the spring 18.
Figure 2 shows the rack gear-device on a larger scale
in side view. The rack 2~ is adjustable vertically as well as
longitudinally rela-tive to the suppor-ting bar lS by means of two
rotatable eccentric cams 25 and 26, which are provided with
screwhead grooves or a hexayon head 27,28 and engaye oblong ho]es
29,30 in the rack 24. The hole 29 ex-tends in -the longi-tudinal
direction of the rack, and the hole ~0 extends in the transversal
direction. The eccentric cam 25 displaces the rack transversal-
ly to adjust the clearance between the teeth, while the eccentric
cam 26 displaces the rack longitudinally to adjust the first and
the last contact position in the spring ~roup of the relay.
The fac-t that the holes are oblong makes it possible to ad]ust
the eccentric cams independently of each other.
The adjustment of the rack enables the actuating means
10,11,12 to be pushed inwards a certain distance of about 1 mm
before the first contact closing of -the spring group occurs
providing protection against acciden-tal discollnection of tele-

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phone conversations, and furthermore the actuating means to
be pushed inwards further a certain distance of about 2 mm after
the last contact disconnection providing security maryin for
interruption of telephone conversations on replacement in case
of an uneven support.
The advantage of described cons-truction compared with ~lown
constructions, where the camshaft of the relay is actuated by
a xotatable arm through a rod mechanism, is that the turning
moment exerted on the camshaft of the relay does not vary dur-
ing the rotating movement but is constant, and self-locking is
prevented.