EP0029489B1 - Key switch - Google Patents

Description

The invention relates to a key switch with a guided in a frame, biased against its axial actuation direction in the rest position and in its working position actuating at least one contact spring set, and with a locking the key shaft in the working position and releasing when pressed again, the switching gate with a heart curve and includes a cam follower guided therein, the switching link and the cam follower being able to be moved in an approximately perpendicular triggering direction to the actuating direction of the push button shaft and the plane of the heart curve, relative to each other, for external control of the locking position of the switching lock independently of the key actuation.

Such pushbuttons are preferably used in telecommunications systems, for example in telephone sets, to control the operating state, for example from the dialing state to the receiving state and vice versa, and on the other hand to control an additional function such as listening.

From DE-C-1 179 259 a push button switch is already known, which is designed for double-pressure actuation. In this case, a push-button shaft actuating the contact spring sets is locked by means of a key switch when depressed for the first time and released from the locked working position when depressed again. The key switch used has a backdrop with a heart curve, in which a guide pin fastened to the push button shaft and movable with it slides and automatically ensures the locking or releasing of the push button shaft when passing through the heart curve. It is also already known to design such a switch lock with a heart labyrinth, in which a ball slides, which is freely movable in a groove transversely to the direction of movement of the part to be locked, for example the pushbutton shaft, and together with the heart labyrinth the locking or the release brings about.

In addition to the simple reversal of the operating state, it has now often been found necessary in practice to additionally change the operating state influenced by the push-button switch as a function of other functions of a telephone set, for example picking up or hanging up the handset. With a simple push-button switch, it is necessary to release the locking status by manual operation again, in accordance with the previously set operating status. This leads to cumbersome handling and can cause operating errors.

To overcome this practical disadvantage, a push-button switch according to the preamble of claim 1 is described in DE-B-1 415 591. In this pushbutton switch, a locking lever with a heart curve is attached to the pushbutton shaft that is moved in the longitudinal direction when the switch is actuated, and a locking pin engages in this when the pushbutton is actuated. This locking pin is in turn attached to the armature of an electromagnet mounted in the frame. To release the locking position of the key switch, the electromagnet is excited so that the locking pin is pulled out of the heart curve and the key shaft together with the locking lever is released for return movement to the rest position.

In such a known arrangement, it proves in many practical cases, for example when used in telecommunications systems, to be very disadvantageous in that electrical energy is required for the external triggering of the locking position by an electromagnet. Especially in telecommunications networks with their own power supply, this additional pulsed current load is neither desirable nor permissible.

Furthermore, DE-A-2 846 198 describes an electrical switch which can be locked in its working position by means of a catch. This catch is fixed in a holding body made of fusible material, which can be melted by electrical heating, so that the catch is released and thus the locking position of the push button switch is released. The external triggering is also based on an electrical power supply in this switch.

From DE-A1-2 653 470 a key switch system for electromagnetic and mechanical interlocks is known, in which the key shaft is locked by means of a locking mechanism after being depressed. This locking mechanism can be controlled by a magnetic coil by electrical excitation such that the locking position is released.

DE-A-1 064 562 also describes a light button for telecommunications systems, the switch lock of which corresponds to that of DE-G-1 179 259 mentioned above, that is to say no external triggering is permitted.

The object underlying the invention is to develop a push button switch of the type mentioned in the preamble of claim 1 in such a way that the external triggering is possible without the use of electrical energy.

According to the invention, this object is achieved by the features mentioned in the characterizing part of claim 1.

In this embodiment according to the invention, it is possible, for example, to bring about the external mechanical triggering in a telephone set by the part of a hook switch that is moved when the handset is placed and / or lifted. Is of particular advantage thereby that only very small mechanical forces are required for pivoting the rocker provided, since for example the mechanical forces available in a telephone are limited due to the limited weight of the handset and the actuating force required for the hook switch itself.

Particularly preferred refinements and developments of the push button switch according to the invention are characterized in the subclaims.

• Fig. 1 eine Seitenansicht eines ersten Ausführungsbeispiels des erfindungsgemäßen Tastschalters mit Teillängsschnitt der Schaltereinheit, wobei das Schaltschloß in Ruhestellung dargestellt ist;
• Fig. 2 eine vereinfachte Seitendarstellung des Tastschalters der Fig. 1, wobei das Schaltschloß in Lösestellung verschwenkt ist;
• Fig.3 eine Schnittansicht der Schaltereinheit entlang der Linie A-A der Fig. 2;
• Fig.4 eine perspektivische Darstellung der Spindel und Sternglocke des Schauzeichens;
• Fig. 5 eine Seitenansicht des Schaltschlosses, gesehen von links in der Fig. 1;
• Fig. 6 eine Rückansicht des in der Fig. 5 dargestellten Schaltschlosses;
• Fig. 7 eine vereinfachte Seitenansicht eines zweiten Ausführungsbeispiels des erfindungsgemäßen Tastschalters mit Teilschnitt des Schaltschlosses;
• Fig. 8 eine Seitenansicht des Schaltschlosses, gesehen von links in der Fig. 7; und
• Fig. 9 einen Teilschnitt des Auslösehebels entlang der Ebene B in der Fig. 7.

The invention is explained in more detail below with reference to the drawing; it shows

• Figure 1 is a side view of a first embodiment of the push button switch according to the invention with partial longitudinal section of the switch unit, the switch lock being shown in the rest position.
• Fig. 2 is a simplified side view of the key switch of Figure 1, wherein the switch lock is pivoted in the release position.
• 3 shows a sectional view of the switch unit along the line AA of FIG. 2;
• 4 shows a perspective view of the spindle and star bell of the indicator;
• Fig. 5 is a side view of the key switch, seen from the left in Fig. 1;
• Fig. 6 is a rear view of the switch lock shown in Fig. 5;
• 7 shows a simplified side view of a second exemplary embodiment of the push-button switch according to the invention with a partial section of the switch lock;
• Fig. 8 is a side view of the key switch, seen from the left in Fig. 7; and
• 9 shows a partial section of the release lever along plane B in FIG. 7.

As can be seen from FIGS. 1 and 2, the push button switch consists of a frame 10 with a base 11, on which, on the one hand, a bearing block 13 for a release lever 15 and, on the other hand, an upwardly projecting holder 12 for the actual switch unit 30 are molded or attached are. The bracket 12 and the bracket 13 are aligned with each other such that one end of the trigger lever 15 pivotally mounted on the journal 14 of the bracket 13 can engage with an actuating element 72 of the switch 60 of the switch unit 30. As shown schematically in FIG. 1, the arm 82 of the release lever 15 projecting from the switch unit 30 can be actuated by a fork plunger 16 which moves together with the fork 18 of a telephone set when a handset 17 is placed or removed. As can be seen from Fig. 1, in this embodiment, both a pivoting movement of the trigger lever 15 from the position shown in solid lines and the pivoting movement in the opposite direction, starting from the position of the trigger lever shown in broken lines, the desired engagement with the actuating element 72 of the key switch 60 bring about that in both cases the actuating element 72 is pressed to the right in FIG. 1.

1 and 3 in particular that the switch unit 30 has a frame 31 which is attached to the holder 12 of the frame 10 in a suitable manner, for. B. is fastened by screwing. In the frame 31, a push button shaft 32 is slidably guided in the longitudinal direction. The push-button shaft 32 consists of a tubular sleeve 34 and a switching cam 33 attached or molded to the lower end thereof, which is provided on its lower outer peripheral edge with bevels (3) for actuating the contact spring sets 39 which are insulated in a contact base 40. In the lower end face of the switching cam 33 of the push-button shaft 32, two downwardly projecting guide shafts 38 are fastened, which can be slid in the corresponding bores of the contact base 40 when the push-button shaft 32 is actuated. Springs 37 for resetting the push-button shaft 32 against its actuating direction are arranged on these guide shafts 38, each of which is supported on the one hand on the lower end face of the switching cam 33 and on the other hand on the upper side of the contact socket 40.

A button head 36 is attached to the upper end of the button shaft 32, outside the frame 31 and the frame 10. This key head 36 serves on the one hand for manual actuation of the key switch and on the other hand as a protective cap for the indicator 50 accommodated in its interior cavity. In order to make the indicator 50 visible from the outside, the key head consists of a material which is transparent at least on the upper end face, e.g. B. made of plastic.

The display part of the indicator 50, which is visible through the transparent button head 36, is designed like a conventional star indicator and therefore does not require any detailed explanation. It consists of a cap-shaped diaphragm 52, divided into sectors of 60 ° in each case, and a star bell 51 which can be rotated back and forth within this diaphragm 52 by approximately 60 ° and is provided with sector-shaped color markings, which is particularly clear in FIGS is recognizable.

Projecting axially downward on this star bell 51 is a spindle 53, which is received in an axial bore 41 in the tubular sleeve 34 of the push-button shaft 32 and is rotatably guided therein in the radial direction. The spindle 53 is generally cylindrical in shape, but extending over part of its length is a spiral helical surface 54 which is axially closed on both sides by radial shoulders 57 at a distance from the respectively adjacent ends of the spindle, so that at both ends of the spindle in each case a cylindrical spindle collar 58 remains, which is the radial one Guidance of the spindle 53 within the axial bore 41 ensures rotation. The axial fixation of the spindle 53 is ensured by a spindle counter bearing 56 formed centrally in the diaphragm 52, on which the uppermost point of the star bell 51 is rotatably supported.

A switching pin 55 is provided transversely to the direction of actuation of the push-button shaft 32 and runs diametrically through its longitudinal center axis, the two ends of which are anchored in diametrically opposite bores of the frame 31 of the switch unit 30. This switching pin on the one hand passes through two diametrically opposed, longitudinal slots 35 in the tubular sleeve 34 of the push-button shaft 32 and, on the other hand, slidably abuts the helical surface 54 of the spindle 53 of the indicator 50.

This arrangement ensures that the helical surface 54 of the spindle 53 slides on the switching pin 55 fixed in the frame 31 and forcibly executes a rotational movement when the push-button shaft 32 is depressed or when it returns from the locking position. In this way it is achieved without the use of external energy that when the push-button shaft is depressed and also when it returns in the opposite direction, the star bell 51 fixedly connected to the spindle 53 is rotated by a predetermined angle, so that the color markings of the star bell 51 either from the fixed aperture 52 are covered or released and made visible. The switch positions of the pushbutton switch are thus forcibly mechanically coupled directly to the two display positions of the indicator 50.

The switch lock 60 of the embodiment of the push-button switch shown in FIGS. 1 and 2 has a rocker 70 which can be pivoted in bearings 71 attached to the frame 31 of the switch unit 30 about a rocker axis aligned transversely to the actuating direction of the push-button shaft 32. The part of the rocker 70 projecting downward from the rocker axis 64 is equipped with an actuating element 72 in the form of a freely rotatable roller and to the left in FIG. 1 by means of a return spring 73 which is supported on the frame 31 biased.

As is shown in detail in FIGS. 5 and 6, on the side of the rocker 70 facing away from the frame 31, a shifting link 65 designed in the form of an arm movable on one side about a pivot bearing 63 is attached. At its free end, which can be pivoted on both sides in the direction of the arrows in FIG. 5, a heart curve 66 of known shape, which is open toward the frame 31 of the switch unit 30, is formed in this switching link 65. Between the part having the heart curve 66 and the pivot bearing 63, a transversely extending recess 69 is formed in the switching link 65, which is interspersed with play by a spring pin 67 anchored to the rocker 70. The spring pin 67 carries springs 68 on both sides of the shift gate, which are supported on the one hand on the rocker 70 and on the other hand on the associated side of the shift gate 65, so that the heart curve 66 of the shift gate is biased into a predetermined rest position and can be deflected from this rest position to both sides .

The second element of the switch lock 60 which interacts with the heart curve 66 of the switching link 65 is designed in the form of a guide pin 61 anchored in the push-button shaft 32 and projecting laterally transversely to its longitudinal axis. This guide pin protrudes through an elongated recess 62 formed in the frame 31 parallel to the direction of movement of the push-button shaft and beyond the outer surface of the frame 31 so that its free end can engage the switching link 65.

When the push-button shaft 32 is depressed in the actuating direction, starting from the rest position shown in FIG. 2, the guide pin 61 moves downwards together with the push-button shaft 32 and initially slides along the upper outer edge 65a of the switching link 65 (see FIG. 6), until he enters the entry opening 66a of the heart curve 66. At the same time, the shifting gate 65 is pivoted to the right in FIG. 6 against the bias of the spring 68. After the push-button shaft has reached its lower end position, it is released again and pressed upwards by the springs 37 against the direction of actuation. Under the action of the spring 68 shown on the right in FIG. 6, the shifting link 65 is now pivoted to the left, while the guide pin 61 moves upward in the heart curve 66 until it engages in the locking groove 66b. As a result, the upward movement of the push-button shaft 32 is stopped in the locking position and the switch unit remains in its locked working position in which the contact spring sets 39 are actuated by the switching cam 33. This switching state is shown in FIG. 1.

For manual release of the locking state of the pushbutton switch, the pushbutton shaft 32 is pressed downward again in the actuating direction, as a result of which the guide pin 61 emerges from the catch groove 66b along the heart curve 66 to the bottom right. If the push-button shaft is released in this fully pressed position, it moves together with the guide pin 61 under the action of the springs 37 upward against the actuation direction and the guide pin 61 slides upward on the right edge of the switching link 65 (FIG. 6), until it returns to its released rest position above the shift gate 65. During this upward movement of the guide pin 61, the switching link 65 is pivoted counter to its spring preload to the left in FIG. 6 and then, after the guide pin 61 has been released upward, returns to its rest position determined by the springs 68. Now the switch unit 30 is in its unlocked rest position, in which the Kon clock spring sets 39 are not actuated. In this respect, these functions correspond to a conventional push button switch with double pressure actuation.

In the push button switch designed according to the invention, however, the locking position of the push shaft 32 and thus the working position of the contact spring sets 39 can be released without manual intervention in that the rocker 70 of the switch lock 60 from the position shown in FIG. 1 into the position shown in FIG. 2 shown position is pivoted against the biasing force of the return spring 73. During this pivoting movement, the shifting gate 65 together with the rocker 70 is moved away from the frame 31 in such a way that the guide pin 61 slides out of the catch groove 66b of the heart curve 66 and, together with the push-button shaft 32, freely moves upward against the actuating direction under the action of the springs 37 can move so that the key shaft 32 comes to its rest position in which the contact spring sets 39 are not actuated. A one-time pivoting of the rocker 75 carrying the rocker switch 65 of the key switch 60 thus ensures that the push button switch returns to its rest position if it was in the locked position before actuation of the rocker 70 or remains in its rest position if it had previously been used .

In the embodiment of the pushbutton switch shown in FIGS. 1 to 7, the pivoting movement of the rocker 75 and thus the release of the locking position of the switch lock 60 is achieved simply by the fact that on the actuating element 72 of the rocker 70, which is designed as a freely rotatable roller, the pretensioning force of the return spring 73 overcoming force is exerted. For this purpose, the two-armed trigger lever 15 is pivotally mounted on the frame 10 of the pushbutton switch, the lever arm facing the switching lock at the free end of which carries two mutually angled sliding surfaces 80 and 81, each of which can slide along the actuating element 72 when the trigger lever 15 is pivoted and this presses against the return spring 73 towards the frame 31, that is, the rocker 70 is pivoted in the desired sense to release the switch lock. From Fig. 1 it can be seen that this function is possible starting from two pivot positions of the trigger lever 15. Starting from the position of the trigger lever 15 shown in solid lines, the sliding surface 81 causes the rocker 70 to pivot, while in the reverse movement, starting from the position of the trigger lever 15 shown in broken lines, the sliding surface 80 engages with the actuating element 72.

The other lever arm of the trigger lever 15 is designed as a fork-like slotted arm 82, the fork prongs of which engage around the fork plunger 16 of the fork 18 of a telephone set (not shown). When the handset 17 is placed on the fork 18, the fork plunger 16 is moved downward in FIG. 1, whereby the release lever 15 is pivoted upward from the position shown in solid lines in FIG. 1. Similarly, when the handset 17 is removed, the release lever 15 is automatically pivoted out of the position shown in dash-dotted lines in FIG. 1, the switch lock 60 again being unlocked in the manner described above. For precise adjustment of the interaction of the slotted arm 82 with the fork plunger 16, the fork opening of the slotted arm 82 can be adjusted by means of a screw 83.

This exemplary embodiment of unlocking the switch lock 60 is particularly advantageous in practice in the case of a telephone apparatus if, for example, a listening device or a loudspeaker device is switched on by the push-button switch. Whenever the handset is removed from the fork or put back on it, it is ensured at the same time that the key switch is returned to its unlocked rest position, in which, for example, the monitoring device is switched off. This can ensure that the monitoring device does not remain switched on inadvertently.

A further embodiment of the push-button switch according to the invention is shown in FIGS. The parts corresponding to the embodiment of FIGS. 1 to 6 are provided with the same reference numerals.

As can be seen in particular from FIGS. 7 and 8, this exemplary embodiment differs from the one explained above, in particular in the design of the switch lock 100. The switch gate of the switch lock 100 is formed in the side face of the push-button shaft 85, that is to say with the push-button shaft when actuated Heart curve 84, which can be moved up and down, is also of conventional construction. The second element of the switch lock 100 which interacts with the heart curve 84 for locking purposes is shown as a guide pin 74 which is connected to a rocker 75 which is pivotably mounted on the outer surface of the frame 31 of the pushbutton switch. As shown in FIG. 8, this rocker 75 can be pivoted by means of a rocker shaft 96 in bearing blocks 97 attached to the frame 31. A spirally wound spring 78 is attached to the rocker shaft 96 and has two free straight legs 78a and 78b. The lower leg 78a of the spring 78 is supported on the frame 31, while the upwardly projecting leg 78b is fastened to the outside of the rocker 75 by means of a spring fixation 95. This arrangement of the spring biases the rocker 75 against the frame 31 in the rest position. The preferred below the cradle shaft 96 part of the rocker 75 has designed as a freely rotatable roller actuator 72, as shown in FIG., The _"sliding surfaces 80 and 81 of a trigger lever 90 can engage to pivot the rocker 75.

In the part of the rocker 75 located above the rocker axis 96, a recess 77 is formed, in which a slide 76 is received so as to be displaceable transversely to the actuating direction of the push-button shaft 85. Attached to the carriage 76 is the guide pin 74 which, when the rocker 75 is in the rest position, projects through a slot 98 in the frame 31 and can engage with the heart curve 84 of the push-button shaft 85. The laterally displaceable in the rocker 75 together with the guide pin 74 slide 76 is biased by the upper leg 78b of the spring 78 into a rest position from which it can be deflected on both sides when the guide pin 74 engages with the heart curve 84. To guide the leg 78b, two guide brackets 79 are attached to the outside of the rocker 75.

As long as the rocker 75 is in the rest position under the pretension of the lower leg 78a of the spring 78, the guide pin 74 interacts with the heart curve 84 in the push-button shaft 85 in the same way as already described above with reference to the embodiment in FIGS 6 has been explained. Starting from the locking position of the key switch as shown in FIG. 7, unlocking of this state can also be brought about by pivoting the rocker from its rest position and thereby pulling the guide pin 74 out of the heart curve 84. The key shaft 85 is thereby released and returns up to its rest position, in which the contact spring sets are not actuated.

Although not shown in the drawing, the guide pin 74 and the slide 76 of the rocker 75 can also be replaced by a ball which can move freely in a groove in the rocker 75 if the heart curve 84 is suitably known.

The trigger lever 90 shown in the exemplary embodiment in FIG. 7, the function and mode of actuation of which completely correspond to the trigger lever 15 of the exemplary embodiment in FIG. 1, is designed in a special way. Its lever arm facing away from the switching lock 100 is designed as a fork-shaped slotted arm 91 which is pivotally and fixably attached to the main body of the release lever 90 by means of a bearing pin 94. To enable the angle to be adjusted, an arc slot 92 is formed in the slotted arm 91, through which, as can be seen in particular from FIG. 9, a clamping screw 93, which can be screwed into the main body of the release lever 90, projects. The resulting angular adjustment of the slotted arm 91 allows the interaction of the trigger lever 90 with, for example, the fork plunger 16 of a telephone set to be precisely adjusted in a particularly advantageous and simple manner, as already explained with reference to FIG. 1.

Claims (6)

1. Push-button having a key shaft (32; 85), which is guided in a frame (31), which is biassed in the inoperative position against its axial acutation direction and which in its operational position actuates at least one resilient contact assembly (39), and also having a switch latch (60; 100), which retains the key shaft (32; 85) in the operational position and which releases it in the event of repeated acutation and which comprises a switching gate (65) having a cardioid curve (66; 84) and a curve-following member which is guided in the latter, wherein the switching gate (65) and the curve-following member may be disengaged from eacht other in a release direction, which is substantially perpendicular to the actuation direction of the key shaft (32; 85) and the plane of the cardioid curve (66; 84), in order to release the retaining action of the switch latch (60; 100) in an externally controlled manner irrespective of the key actuation, characterised in thrt the switching gate (65) or the curve-following member is mounted on a rocker (70; 75) which is pivoted on the frame (31) and in that the rocker (70; 75) is biassed in the inoperative position towards the frame (31) and may be swung horizontally against the bias through mechanical external control in the release direction.

2. Push-button according to claim 1, characterised in that the rocker (70; 75) is provided with an actuating element (72) for the external control, which element is spaced from the axis (64; 96) of the rocker's pivotal mounting.

3. Push-button according to claim 2, characterised in that the actuating element (72) may be moved against the bias of the rocker (70; 75) through engagement with in each case one of two sliding surfaces (80; 81) on a release leyer (15), the said sliding surfaces (80; 81) being arranged at angles to one another.

4. Push-button according to one of the claims 1 to 3, characterised in that the curve-following member is constructed as a guide pin (61).

5. Push-button according to one of the claims 1 to 4, caracterised in that the curve-following member is constructed as a sphere.

6. Push-button according to one of the claims 1 to 5, characterised in that the kay shaft (32) bears a key head (36), which is at least partly transparent and in which there is arranged a visual indicator (50) showing the respective switch position.

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