FIELD OF INVENTION

The present invention relates to a connection arrangement for connect¬ ing an additional speech device in a telephone instrument of the type "DIAVOX" Ca trade mark), which arrangement comprises a push button mechanism and a cam shaft relay known per se.

DESCRIPTION OF PRIOR ART

It has long been desirable that telephone instruments, provided with the usual lowspeaking device, have the capability of having added thereto an. additional speech device by means of a simple connection. An example of such an additional speech device is a loudspeaking ele¬ ment, the main handset and so on. In presently known telephone as, for example, "ERICOVOX" this can be carried out by means of connection via an additional spring set.

In the presentlydeveloped telephone "DIAVOX" described in, for ex¬ ample, "Ericsson Review" No 3, 1977 (pages 112-113) an additional speech device for loudspeaking function is provided in the instrument, a connection arrangement being required to achieve said connection between the two telephone functions.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a connection arrange¬ ment in a telephone instrument of the above mentioned kind for connec¬ tion between two telephone functions, for example, the lowspeaking and the loudspeaking function by utilizing contact means already ex¬ isting in the telephone instrument. Accordingly, the invention is characterized as it appears from the characterizing part of claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to the accompanying drawings, in which:-

Fig 1 is a side-view of a connection arrangement according to the i vention;

Fig 2 is a plan view of the arrangement shown in Fig 1; Fig 3 is an exploded view of a push button mechanism included in th arrangement according to the invention;

Fig 4 is a cross sectional view of a telephone instrument including the arrangement according to the invention;

Fig 5 shows the same cross section as in Fig 4 but with the handset raised; and Fig 6 shows the same cross section as in Fig 5 but with connection arrangement activated.

PREFERRED EMBODIMENTS

The arrangement will at first be described with reference to Figure 1 and 2 with regard to its construction, whereafter its function in telephone set for connection and disconnection of an additional spe device will be described. The arrangement includes a push button mechanism generally denoted by 1 which includes two push buttons 1a 1b, frame formed supports 1c, 1d, for guiding the buttons 1a, 1b wh these are depressed and a cover 1e which surrounds a locking mechan for the button 1a as it will appear more in detail from the explode view according to Fig 3. The push button 1a is on its one side prov ed with a guiding pin 1f, which is intended to run in a groove 1g shaped in the cover 1e when the push button is pressed down. A tippi element, generally denoted 2 and acting as a flip-flop means is piv ally mounted on the cover 1e by means of shaft 3. The tipping eleme 2 comprises a hollow frame part 2a which surrounds the shaft 3 and arms 2b, 2c. The first arm 2b is provided with a rounded longitudin groove 2d in which the guiding pin 1f may run during the movement o the push button 1a. The second arm 2c is, as it appears best from F 1, provided with a cut-out portion so that a tongue part 2e is form the purpose of which will appear below.

The push button mechanism 1 with associated flip-flop means 2 so fa described is intended to work with a cam shaft relay known per se a

shown in Figs 1 and 2. This consists of a cover 4 which includes a contact spring set shown with contact arms and contact sheets, not shown, in order to carry out a make-before-break contact or only a ake-and-break contact. The relay is described in detail in, for ex- ample, the Swedish patent application 7605033-5. The cam shaft relay has a control member generally denoted 5. This is pivotally mounted on the shaft 6 and comprises a cover 5a, which includes a ratcheted quadrant 5b firmly connected to a rocker arm 5c. The cover 5a is pro¬ vided with a pin 5d which in the position of the rocker arm shown in Fig 1 bears against the tongue formed part 2e of the arm 2c. The ratcheted quadrant 5b engages a gear wheel 7 which is mounted on a same shaft 8 as the cam in the cover which during movement thereof makes the contact changes. The soldering tabs protruding out of the cover 5a of the cam shaft relay are indicated at 9a-d and 10a, b de- note fixed guiding pins on the underside of the cover 5a in order to facilitate the mounting of the cover on an underlying circuit card.

Fig 3 shows an exploded view of the inner parts of the push button mechanism in order to illustrate its function. A slide 11 is located in the cover 1e and can glide as shown with the arrows a and b along a groove 1k in the bottom 1 of the cover. The slide 11 is therewith biased by means of a spring 12 and is provided with two recesses 11a and 11b situated just opposite each of the push buttons 1a and 1b, respectively. The recess 11a is shaped to form a hook 11c and the re¬ cess 11b is shaped to form a bevel 11d. The two buttons are each pro- vided with a respective glide tap 1h, 1j protruding perpendicularly to the slide 11, the cross section of which tap is substantially semi¬ circular. The push button 1a is, furthermore, provided with the control pin 1f as described above.

When the push button 1a is depressed for the purpose of activating the cam shaft relay by turning the tipping element 2, the rounded surface of the ^* tap 1h"-bears against the glide surface (dotted ⁾ of the hook 11c. Continued (depression of the push button 1a causes the tap 1h to glide along the sliding surface. This forces the slide to move in a direction perpendicular to the depressing direction of the push button

as shown by arrow a. When the push button 1a is nearly completely de pressed, the slide moves according to arrow b under the influence of the spring 12 and the hook is moved over the tap 1h so that its uppe plane surface bears against the hidden lower surface of the hook. Th button 1a is thereby Locked in its depressed position. The locking c be released by depressing the push button 1b. The curved surface of the tap 1i glides along the surface (dotted) of the bevel 11d so tha the slide moves according to the arrow b and the hook releases its grip of the tap 1h, which means that the button 1a returns to its original position under the influence of the spring 13. The return springs 13 and 14 for the push buttons 1a and 1b are placed in cylin drical holes of the two guides 11, 1m.

The function of the arrangement in the instrument will now be explai ed more in detail with reference to the figures 4-6 which show a cro section through the cover of the instrument nearest to the right of the position of the push buttons 1a, 1b on its front cover. In Fig 4 the bottom plate of the instrument is denoted by 15, 16 denotes its rear cover and 17 the front cover. The hook switch of the telephone is denoted by 18 and the element 18a indicates a guide, not shown in deta l, for the hook switch. This is in Fig 4 shown in its depressed position (the rest position of the instrument) by means of the on- hook handset (not shown). The hook switch cradle of the instrument i denoted by 19 and comprises a head formed part 19a shaped as an en¬ velope curve 19b and two arms 19c, 19d. The arm 19c bears at its end part against the Lower part of the hook switch 18 and the arm 19d is at its end part fixed to a thread spring 20 tightened into the rear cover 16 of the telephone instrument. The hook switch cradle 19 is supported at its pointed part 19c towards a supporting element 21 firmly moulded to the underside of the cover 16.

The cover 1e of the push button mechanism and the cover 4 of the cam shaft are rigidly mounted on a circuit card 22. The circuit card is mounted in the telephone set in a known manner by means of 1jhe suppo 23 and the grip element 24 as appears from the Swedish patent applic tion 7711945-1. Other designations used in Figs 4-6 indicate the sam

elements as the corresponding elements in Figs 1, 2. For the sake of clarity, the ratcheted quadrant 5b and the gear wheel 7 have been ex¬ posed in Figs 4-6. In the rest position of the instrument according to Fig 4, the position of the hook switch cradle is fixed by means of the hook switch 18 and the tensed spring 20, the surface 19b bearing with¬ out pressure against the rounded part of the rocker arm 5c of the control member 5 of the cam shaft relay.

Figure 5 shows in more detail the position of the cam shaft when the handset is not in its cradle. The hook switch cradle 19 has therewith, owing to the influence of the spring 20, been turned counter-clockwise around its supporting point and its arm 19c has raised the free mov¬ able hook switch 18. The head formed part 19a of the hook switch cradle has simultaneously been turned somewhat counter-clockwise and forced the rocker arm 5c somewhat clockwise. This implies that a con- tact function (make-before-break contact) has been carried out by the spring group in the cam shaft relay so that the telephone instrument is connected to its lowspeaking state which means that connection of the telephone instrument and the speech transmission have occurred.

In the position according to Fig 6, the push button 1a of the push button mechanism has been pressed down, while the position of the hook switch cradle 19 and therewith the position of the hook switch 18 are unchanged. Depressing the push button 1a causes the control pin 1f to force the element 2 to turn counter-clockwise around its axis 3, whereby the tongue-formed part 2e will gradually come into contact with the tap 5d on the cover 5a.On continued depression to the posi¬ tion shown in Fig 6, the tongue-formed part 2e of the tipping arm will force the rocker arm 5c of the cam shaft relay to further be turned clockwise. This means that still another contact function besides the one carried out under influence of the hook switch cradle, i e one further make-before-break contact is carried out by the cam shaft relay. By this later contact the additional speech device is connected to the telephone instrument, for example, loudspeaking means and the handset is disconnected, the telephone instrument changing from its lowspeaking to its loudspeaking position. The cam shaft relay maintains

its occupied position as Long as the push button 1a is depressed whi thus indicates that the additional speech device is connected. As it appears from Fig 6, the handset can be put on, since onLy the hook switch 18 and the hook switch cradle 19 return to the original posi tion according to Fig 4, while the position of the rocker arm remai unchanged. The telephone instrument can, in addition, be provided wi elements not in detail described here which achieve the result that when the handset is off-hook, the push button 1a returns and the spr group once again occupies the position according to Fig 5, that is the lowspeaking position. The loudspeaking position can of course al be obtained with on-hook handset according to Fig 4 by depressing th push button 1a which then remains in its depressed position. When li ing the handset, the spring group returns to the position according Fig 5.