HOOK SWITCH FOR A TELEPHONE INSTRUMENT OF SINGLE BODY TYPE

Abstract: Hook switch arrangement for a telephone instrument of single body type. The arrangement comprises actuating means (10, 11, 12) protruding through the bottom surface of the instrument to actuate the hook switch (17) of the instrument by means of a support on which the instrument is placed after a call. The actuating means cooperate with elements actuating the springs of the hook switch, said elements comprising rods (13, 14) provided with arms (20) to convert the movement of the actuating means to rotating movement and a spring actuated rack arrangement (15) engaging a gear (16) which by its rotation actuates the springs of the hook switch. The rods (13, 14) are provided with further arms (21) which at their rotation by engagement with the rack arrangement displace the same.

Description: HOOK SWITCH FOR A TELEPHONE INSTRUMENT OF SINGLE 80DY TYPE. FIELD OF THE INVENTION The invention relates to a telephone instrument of single body type comprising actuating means protruding through the bottom surface of the instrument for actuating the hook switch of" the instrument by means of a support on which the instrument is placed after a call said protruding actuating means comprising parts distributed along the periphery of the bottom surface, each part cooperating with ele¬ ments actuating the springs of the hook switch for transmitting the movement of the actuating devices to these elements. DESCRIPTION OF PRIOR ART Arrangements of the mentioned type are previously known, for example from the US patent No 3562447 and are particularly suitable if it is desired to guarantee a correct hook switch function also when the support is uneven. SUMMARY Of THE INVENTION The known arrangement which comprises two longitudinally displaceable arms which through their displacement actuate a- rotatable contact element has the disadvantage that the power required to actuate the contact element is relatively great at the beginning of the movement and smallest in the middle of the displacing movement when the contact element consisting of a rotatable arm is perpendicular to the direction of the displaceable arms. In unfavourable cases a locking can occur so that the return spring cannot bring the contact element back to its rest position. The object of the invention is to achieve a hook switch function with an even and relatively low operating power. By the arrangement accoi— ding to the invention also easier adjustment, easier mounting and eli- mination of the risk of self-locking is achieved. The invention is characterized as appears from the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be closer described below by means of an embodiment with reference to the accompanying drawing in which Figure 1 shows the arrangement according to the invention in perspective and Figure 2 shows the rack in side view. PREFERRED EMBODIMENT Figure 1 shows the arrangement according to the_ nvention with the parts of a telephone instrument necessary to explain the idea of the invention while the other parts have been omitted. A long actuating means is designated 10 and two shorter actuating means are designated 11 and 12 which, in a telephone instrument of single body type for example the telephone instrument ERIC0F0N, protrude through the bottom surface of the instrument (not shown in the drawing) and are pressed into the instrument when placing the same on a support and then actuate elements which in their turn actuate contact springs in the contact device of the instrument. Said elements comprise rods 13, 14 rotatable by * the actuating means and a rack arrangement 15 displaceable in the longitudinal direction by the rotation of at least one of said rods and having an adjustable rack 24 cooperating with a gear 16 on the cam¬ shaft of a camshaft controlled relay 17 known per se. The rod 13 co¬ operates with the actuating means 10 and the rod 14 cooperates with the actuating means 11 and 12 by their 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 at the rotation of the rod displaces the rack arrangement in longitudinal direction against the power of a spring 18. The rods 13, 14 are arranged in such a way that the rack arrangement 15 is actuated in¬ dependently of whether only one of the actuating means or all of them are pushed on. As appears from the drawing the arm 21 of the rod 13 is turned anti-clockwise when the actuating means 10 is pressed in¬ wards and by means of the projection 22 displaces, the rack arrange- ment against the power of the spring 18. If only one of the actuating means 11 or 12 should be pressed inwards the arm 21 on the rod 14 is turned clockwise and by means of the projection 23 displaces the rack arran ement a ainst the ower of th s rin 18. Fiαur 2 the rack gear—device in a larger scale in side view. The rack part 24 is adjustable vertically as well as longitudinally relatively to the supporting part 15 by means of two rotatable eccentrics 25. and 26 which are provided with screwhead grooves or a hexagon head 27, 28 and are engaging oblong holes 29, 30 in the rack 24. The hole 29 extends in the longitudinal direction of the rack and the hole 30 in the trans¬ versal direction. The eccentric 25 displaces at turning the rack traπsversally to adjust the allowance between the teeth while the eccentric 2ό displaces the rack longi udinally to adjust the fi st and the last contact function in the spring group of the relay. The fact that the holes are oblong makes it possible to adjust the eccen¬ trics independently of each other. The purpose with the adjustment of the rack is that the actuating means 10, 11, 12 shall be able to be pressed inwards a certain distance of about 1 mm before the first contact closing of the spring group occurs (protection against unvolαntary disconnection of telephone con¬ versations) furthermore it shall be possible after the last contact disconnection to press the actuating means further inwards a certain distance of about 2 mm Csecutity margin for interruption of telephone conversations on replacement in case of an uneven support). The advantage of a construction according to the invention compared with the known construction where the camshaft of the relay is actu¬ ated by a rotatable arm through a rod mechanism is that the turning moment exerted on the camshaft of the relay does not vary during the rotating movement but is constant and -self-locking is prevented.

Claims: WHAT WE CLAIM IS : 1 Hook switch arrangement for a telephone instrument of single body type comprising actuating means (10, 11, 12) protruding through the bottom surface of the instrument to actuate the hook switch (17 ) of the instrument by means of a support on which the instrument is placed after a call, said protruding actuating means (10, 11, 12) comprising parts distributed along the periphery of the bottom surface, each part cooperating with elements actuating the springs of the hook switch (17) for transmitting the movement of the actuating means to these elements, characterized in that said elements comprise rods (13, 14) provided with arms (20) for converting the movement of the actuating means (10. 11.12) into a rotating movement and a spring actu¬ ated rack device (15, 24) engaging a gear (1ό) on a rotatable contact element actuating/when rotating,the springs of the contact switch, the rods (13, 14) being provided each with a further arm (21) which at the turning of the respective rod by engagement with the rack device displaces the same against the power of the spring (18). 2 Hook switch arrangement according to claim 1, characterized in that the rack device comprises a support part (15) and a rack part ( 24 ) adjustable relatively to the support part, said rack part being fixed on the support part by means of eccentrics (25, 26) en- gaging oblong holes ( 29, 30) in the rack part, so that the " rack part (24) can be displaced transversally as well as longitudinally on the support part ( 15 ) to adjust the allowance between the teeth and to adjust the contact function of the spring group respectively.

Inventors: LINDMAN BOERJE LENNART, PETERSON SVEN TAGE
Applicants: ERICSSON TELEFON AB L M, LINDMAN BOERJE LENNART, PETERSON SVEN TAGE
Application year: 1982
Main classification: H04M1
IPC codes: H04M1