EP0160791A1 - Push button switch - Google Patents

Abstract

The invention relates to a push button switch with a housing (1), in which a push button (2) can be moved relative to a housing base (3). A switching plunger (11) is arranged in the housing, which can be displaced longitudinally as well as deflected by a small angular range when the push button is actuated. In the housing there is also a contact bridge (5) which can be jumped around a bearing in a central contact piece between two fixed contacts. The position of the contact bridge is determined by a rocker switch, which is arranged tiltably in the housing. Shift plunger and rocker switch interact here. The counter bearing for the contact bridge forms a cutting edge bearing (32) in the rocker switch. A return spring (70) is provided between the switching plunger and the rocker switch, so that when the push button is in the rest position, the switching plunger assumes a pivoting position that deviates from the central position. Depending on the direction of movement of the push button, the transverse deflection of the switching plunger is brought about by a positive guide.

Description

The invention is based on a push button switch according to the preamble of claim 1.

In general, switches are used to connect or disconnect electrical lines several times. Regardless of which design or actuation principle they work in, they thus offer the operator of a device the opportunity to influence how it works. Switches are thus the interface between man and machine and they cannot be replaced by anything, even though they are also subject to technological change and have reached a very high technical level. Switches of various designs are one of the few electromechanical components in electronics that often have design requirements in addition to the switching function. Because they are arranged on the front panel of a device, they play a decisive role in determining its appearance. It is therefore not surprising that an almost unmanageable range of rotary, rocker, toggle, slide, pushbutton and push-button switches are available in all conceivable designs, colors and sizes. The switch described below belongs to the group of push button switches.

From DE-OS 31 51 501 a push button switch is already known, which consists of a pot-shaped housing, against which a push button is relatively displaceable. On the inside of the push button there is a web projecting into the inside of the switch, around which a switching plunger is pivotally and displaceably mounted. The switching plunger consists of a disc and a wedge-shaped shoulder. Regardless of the push button, a switching rocker is pivotably mounted below the switching plunger with the help of bearing journals mounted in end shields. This switch rocker has a T-like shape with a crossbar and a vertically downward-facing guide shoulder. The crossbar is on the The top is gable-shaped to accommodate the wedge-shaped extension of the switching plunger. The angle of inclination of the two gable halves corresponds to half the swivel angle of the switch rocker. In each of the two switch positions, one half of the gable is in a horizontal position. Two return springs are responsible for pivoting the switching plunger, which are clamped between the switching plunger and the rocker switch on different sides of the attachment. In the guide approach of the switch rocker there is a blind hole that receives a compression spring that is supported on the one hand on the bottom of the blind hole and on the other hand on a contact roller. The bottom of the housing has two identical cam surfaces in roof-like shape, on which the contact roller can slide.

Another push button switch is described in DE-OS 30 46 831. A push button can be moved relative to a rectangular housing. An inward, wedge-shaped extension is formed on the top of the push button. The tip of this approach serves as a tilt bearing for a shift plunger. This consists of a disc and a plunger pointing downwards. The plunger interacts with a wedge-shaped tip of a rocker switch. The rocker switch has a bearing journal on each side, which can rotate in a hole in the housing. The wedge-shaped tip is part of a control curve of the switch rocker. The control curve consists of a central vertex, two flanks descending from this vertex and two surfaces rising from the end of the flanks. The apex is at a certain distance from the bearing journal of the switching rocker, so that in the two switching positions it lies to the side of a plane defined by the bearing axis and the direction of sliding. This ensures that the plunger always hits one of the flanks. A return spring is clamped between the switching plunger and the rocker switch. Due to the inclined position of the switch rocker, the preload on two opposite sides is different. A spring-loaded switching pin is attached to the switching rocker, which presses on a contact rocker which is mounted such that it can be tilted about a fixed contact.

The object of the present invention is to develop a push-button switch of the type mentioned at the outset so that it has a simple mechanical switch position indicator and that, despite the compact design, it is constructed from as few individual parts as possible and can therefore be mass-produced at low cost, the contact force being immediate bar before switching should be maintained or even increased so that there is a long electrical life.

This object is achieved by the features specified in the characterizing part of claim 1.

Advantageous refinements result from the subclaims.

The invention is described below for an embodiment with reference to the drawings.

• Figur 1 in perspektivischer Seitenansicht einen Druckknopfschalter in Explosionsdarstellung,
• Figur 2 eine Seitenansicht des Druckknopfschalters im Schnitt,
• Figur 3 in Perspektivansicht im vergrößerten Maßstab eine Einzelheit des Druckknopfschalters,
• Figur 4 in Perspektivansicht im vergrößerten Maßstab einen Schaltstößel und eine Schaltwippe,
• Figur 5 im vergrößerten Maßstab einen anderen Druckknopfschalter teilweise abgebrochen in Seitenansicht im Schnitt,
• Figur 6 im vergrößerten Maßstab eine andere Ausführungsform eines Druckknopfschalters teilweise abgebrochen in Seitenansicht im Schnitt.

From the figures shows

• FIG. 1 shows a perspective side view of a push button switch in an exploded view,
• FIG. 2 shows a side view of the push-button switch in section,
• FIG. 3 shows a perspective view on an enlarged scale of a detail of the push-button switch,
• FIG. 4 shows a switching tappet and a switching rocker in a perspective view on an enlarged scale,
• FIG. 5 shows another push-button switch partially broken away in a side view in section,
• Figure 6 on an enlarged scale another embodiment of a push button switch partially broken away in side view in section.

The push button switch shown in the figures has a two-part, rectangular housing 1 made of plastic. In the pot-shaped housing base 3, a center contact piece 6 is injected in the middle on the housing base and on the side of the housing walls a fixed contact 7 made of an electrically conductive material. The associated terminal lugs 39 protrude from the bottom of the housing base. The switch is therefore suitable for installation in a printed circuit. The end Metal-made center contact piece 6 has a V-shaped cutting edge bearing 32, which continues in a likewise V-shaped recess 40 in the housing base base in such a way that the recess widens like a funnel towards the interior of the housing.

As can be seen from FIG. 1 below, lateral, protruding guide strips 35 are integrally formed on the housing base 3, specifically on the four housing base edges. In addition, a plurality of protruding locking lugs 36 are provided on the outside of the housing base 3. These locking lugs 36 cooperate with elongated holes 37, which are located in a push button 2. This rectangular push button is also made of plastic and is relatively displaceable relative to the housing base 3. The elongated holes 37 are recessed in two resilient side walls 41 of the push button 2. During assembly, the push button 2 is simply pushed over the housing base 3 until the latches 36 snap into the elongated holes 37. The side walls 41 lie here between the guide strips 35. This snap connection holds the push button on the housing base.

The two resilient side walls 41 are formed on two opposite sides of the pot-shaped push button 2. In the embodiment shown in FIGS. 1 to 4, the push button itself consists of an opaque plastic. At the front of the push button there is a narrow window 38 through which the switch position can be visibly displayed. This is important because the push button returns to its original home position after each actuation.

On the two sides on which there are no side walls 41, as can be seen from FIG. 1 above, a web 18 is formed on the inside of the push button in the sliding direction. The end of the web 18 lies both in the rest position and when the push button is depressed in a V-shaped pocket 17 of a switching plunger 4. The switching plunger 4 made of plastic itself consists of a U-shaped bracket seen from the broad side with an on Base part 11 integrally formed head part 12 and two laterally formed legs 13. Both legs 13 are of equal length and they run into a tapered tip 16 at the free end. Viewed from the narrow side, the head part 12 widens in a mushroom shape with a segment-shaped curved surface 14. On this curved surface there is a label or identification from which the switch position emerges. This label or label is, due to the inclined position of the switching plunger in the rest position, visible in the window 38 of the push button. Two marginal edges 15 of the arch surface 14 are rounded and reinforced.

In the middle of the base part 11 between the two legs 13, a holding pin 19 is formed on which one end of a return spring 10 is supported in the form of a helical spring.

At the mouth end of the V-shaped pocket 17 of the switching plunger 4 lugs 20 are formed on both sides, which cooperate with protruding elevations 28 of a rocker switch 8.

The restoring spring 10 is arranged between the switching plunger 4 and the rocker switch 8, which is partially guided in a blind hole 26 of the rocker switch 8 and is supported on the bottom of this blind hole. This return spring is designed so that it seeks to push the switching plunger and rocker switch away from each other.

The switching rocker 8 molded from plastic is designed in the manner of a two-armed lever with a short and a long arm. The short arm here consists of two resilient side walls 21, which are integrally formed laterally at a distance. This forms a chamber 22 which is open on three sides and receives the base part 11 of the switching plunger 4. In addition, the return spring 10 is arranged between the two side walls 21. At two corners in each case, the side walls 21 carry inwardly directed elevations 28 which interact with the lugs 20 of the switching plunger. On the outside, the side walls each have a spherical elevation 27 about which the rocker switch can be pivoted in a small angular range.

The long arm 23 of the rocker switch tapers slightly in cross section towards its end, since the rocker switch should be pivotable. If it had the same cross-section over the entire length, the long arm 23 would abut the wall of the housing base and a pivoting would thus be prevented.

At the free end, the long arm 23 has on the two outer sides a V-shaped cutting edge bearing 24, the boundary of which is two wedge-shaped Contact surfaces 9 is formed. These contact surfaces together with the cutting edge bearing are laterally raised compared to the long arm 23. As will be explained later, these contact surfaces 9 interact with the tips 16 of the switching plunger. A recess 25 is provided in the long arm between the two cutting edge bearings 24.

The electrical connection between the fixed contacts 7 and the center contact piece 6 produces an E-shaped contact bridge 5 made of metal. Details of this contact system are shown in Figure 3. The contact bridge 5 has two outer snap tongues 29 and a contact tongue 30 which is longer than the snap tongues and arranged between the snap tongues and which has a tubular contact element 42 at the front end. The snap and contact tongue are connected by a connecting web 31. As can be seen from FIG. 3, the contact bridge 5 lies with the edge of the connecting web 31 in the cutting edge bearing 32 of the center contact piece 6. The edge at the free end of the snap tongue 29 lies in the cutting edge bearing 24 of the contact rocker 8. The contact bridge 5 is thus clamped between these two cutting edge bearings and in an inclined position, which is caused by the fact that the preloaded return spring in the installed state tries to push the rocker and switching plunger apart, the switching plunger being pressed against the inner wall of the push button. The contact tongue 30 with its contact element 42 also projects into the recess 25 of the rocker switch 8.

As can be seen from FIG. 2, the housing base 3 has a plurality of integrally formed sliding ribs 33 on the inside, on two opposite sides. These sliding ribs extend almost to the bottom of the housing base. On the mouth side, the sliding ribs 33 are provided with run-on bevels 34 which taper towards the free end. In the exemplary embodiment shown in the figures, as shown in FIG. 1, three sliding ribs are provided on each side.

From Figure 2 it can be seen that the switching rocker 8 rests with its convex elevations 27 on the sliding ribs 33 of the housing base 3. The rocker switch can be swiveled around these elevations in a small angular range. As already mentioned, both the rocker switch and the switching plunger are in an inclined position in the rest position (FIG. 2). If you now press the push button down, the switch plunger is also moved downwards in the inclined position. The switching plunger is carried by the web 18, the end of which is supported on the bottom of the V-shaped pocket 17. Because the return spring 10 is compressed, the pressure with which the contact element 42 is pressed against the fixed contact 7 also increases. When the push button is depressed, the tip 16 of the switching plunger 4 reaches either the right or the left contact surface 9 as the movement progresses. It is then no longer possible to jump from one side to the other without snapping the contact bridge. Finally, the edge 15 of the switching plunger abuts the bevel 34 and while the push button is pressed further, the marginal edge runs along the bevel and forcibly pivots the switching plunger toward the center. The tip 16 presses the rocker switch 8 abruptly over the contact surfaces 9 to the other side. The sliding along the edge 15 on the run-up slopes 34 and then the sliding ribs 33 represents a first positive guide for the switching plunger.

When the push button is released, it returns from the switch position to the initial rest position due to the return spring. Here, the lugs 20 of the switching plunger abut the elevations 28 of the rocker switch and there is a forced rotation of the switching plunger, so that the tip 16 comes to rest on the other contact surface 9 when the push button is depressed again. The forced rotation of the shift plunger thus represents a second forced guidance for the shift plunger.

The inclined position of the switching plunger, which is provided in the rest position of the push button, enables an extremely simple switching position display. In the exemplary embodiment illustrated in FIGS. 1 to 4, the push button consists of an opaque plastic, a window 38 being left free in the push button on the front side.

FIGS. 5 and 6 show further exemplary embodiments for a switch position indicator. In the example shown in Figure 5, the Push button 43 made of a transparent plastic. On the inside of the push button, a cover 44 made of an opaque material is embedded in a recess, which has an opening 47 through which the inscription or marking of the arch surface 14 is visible. This embodiment has the advantage that the housing is sealed.

The push button 45 of the exemplary embodiment according to FIG. 6 also consists of a transparent plastic. A cap 46 is also pushed over the actual push button 45 and has a recess 48 on the front. The inscription or marking of the arch surface 14 is visible through this recess. The housing of the switch of this exemplary embodiment is thus tight and protected against dust and foreign parts.

4/84 Pt. + Hgm

• 1 push button switch
• 2 push buttons
• 3 housing bases
• 4 switching plungers
• 5 contact bridge
• 6 center contact piece
• 7 fixed contact
• 8 rocker switch
• 9 contact surface
• 10 return spring
• 11 base part
• 12 headboard
• 13 legs
• 14 vaulted surface
• 15 edge
• 16 top
• 17 bag
• 18 bridge
• 19 retaining pins
• 20 nose
• 21 side wall
• 22 chamber
• 23 arm
• 24 cutting edge bearings
• 25 recess
• 26 blind hole
• 27 survey
• 28 increase
• 29 snap tongue
• 30 contact tongue
• 31 connecting bridge
• 32 cutting edge bearings
• 33 sliding ribs
• 34 bevels
• 35 guide bar
• 36 latch
• 37 slot
• 38 windows
• 39 connection lug
• 40 incision
• 41 side wall
• 42 contact element
• 43 push button
• 44 cover
• 45 push button
• 46 cap
• 47 opening
• 48 recess

Claims (22)

Push button switch (1) - With a multi-part housing, a push button (2) being displaceable relative to a housing base (3), with a switching plunger (4) which can be displaced longitudinally and deflected transversely to this direction by means of the push button (2), with a contact bridge (5) which can be jumped around a bearing in a center contact piece (6) between two stops, of which at least one stop is designed as a fixed contact (7), With a switching rocker (8) that determines the position of the contact bridge (5), which is tiltably arranged in the switch housing and which has at least one wedge-shaped contact surface (9) for the switching plunger (4), which in a first or second tilting position on the switching plunger ( 4) is aligned and has a position which, when loaded by the shift plunger (4), leads to a moment in the sense of tilting into the other tilted position and a corresponding deflection of the shift plunger (4), and - With a return spring (10), which is supported on the switching plunger (4) and on the switching rocker (8),
characterized in that the counter bearing of the contact bridge (5) is located on the switching rocker (8), the contact bridge pretension being generated by the return spring (10) in the installed state in such a way that in the rest position of the push button (2) the switching plunger (4) only occupies a pivot position deviating from the central position, and
that the transverse deflection of the switching plunger (4) is accomplished by two force guides, of which the first positive guidance is effective when moving from the rest position to the switching position and the second positive guidance is effective when moving from the switching position to the rest position. 2. push button switch according to claim 1,
characterized,
that the switching plunger (4) consists of a U-shaped bracket with a molded on a base part (11) head part (12) and two side legs (13) of the same length. 3. push button switch according to claim 2, characterized in
that the head part (12) has a curved surface (14) on the front with rounded and reinforced edge (15). 4. push button switch according to claim 2, characterized in
that the width of each of the side legs (13) gradually decreases towards the free end in one or more steps and ends in a tip (16) which cooperates with the wedge-shaped contact surfaces (9) of the switching plunger (4). 5. Push button switch according to one of claims 1 to 4, characterized in
that in each leg (13) on the outside, near the connection to the base part (11), a V-shaped pocket (17) is recessed into which a driver of the push button (2) protrudes, the one lying through both ends of the pocket Axis represents the displaceable axis of rotation of the switching plunger (4). 6. Push button switch according to claim 5, characterized in
that the drivers are integrally formed on the inside, projecting and extending in the sliding direction webs (18) which are arranged on opposite sides of the push button (2). 7. push button switch according to claim 2, characterized in
that a holding pin (19) for the return spring (10) is formed on the side of the base part (11) opposite the head part (12) in the sliding direction. 8. push button switch according to one of claims 1 to 6,
characterized,
that each leg (13) has protruding lugs (20) formed on both sides in transverse deflection. 9. push button switch according to one of claims 1 to 8, characterized in
that the rocker switch (8) is designed in the manner of a two-armed lever with a short and a long arm, the short arm being formed by two resilient side walls (21) projecting beyond the width of the long arm, whereby one after Chamber (22) open on several sides for receiving the base part (11) of the switching plunger (4). 10. Push button switch according to claim 9, characterized in
that the long arm (23) of the rocker switch (8) has a tapering cross section towards the free end. 11. Push button switch according to claim 9 and 10, characterized in
that the end of the long arm (23) is provided with at least one cutting edge bearing (24) for the contact bridge (5), the outline of which extends in the sliding direction is formed by the wedge-shaped contact surfaces (9). 12. Push button switch according to claim 11, characterized in
that a recess (25) is provided between two outer cutting edge bearings (24) in the long arm (23). 13. Push button switch according to claim 9, characterized in
that the long arm (23) in the sliding direction of the push button (2) has a blind hole (26) for partially receiving the return spring (10). 14. push button switch according to claim 13,
characterized,
that the return spring (10) is a coil spring. 15. Push button switch according to claim 9, characterized in
that the side walls (21) have convex elevations (27) on the outside. 16. Push button switch according to claim 9, characterized in
that the side walls (21) are designed at the free end with a plurality of inwardly directed toward each other elevations (28) which cooperate with the lugs (20) of the switching plunger (4) in the sense of a forced pivoting of the switching plunger (4). 17. Push button switch according to claim 1, characterized in
that the contact bridge (5) is E-shaped and in one piece, with two parallel, the snap moment providing outer snap tongues (29), and an intermediate, longer contact tongue (30), wherein snap tongues (20) and contact tongue (30) by one transversely arranged to them connecting web (31) are interconnected. 18. Push button switch according to claim 17, characterized in
that the contact bridge (5) with its connecting web (31) in the cutting edge bearing (32) of the center contact piece (6) and with the snap tongues (29) in the cutting edge bearings (24) of the rocker switch (8) is mounted. 19. Push button switch according to claim 1, characterized in
that the housing base (3) has on the inside, on both sides at least one sliding rib (33) with a longitudinally extending run-up slope (34) on which the edge edges (15) of the head part (12) of the switching plunger (4) slide to pivot of the switching plunger (4). 20. push button switch according to claim 1,
characterized,
that the housing base (3) has molded on the outside guide strips (35) for guiding the push button (2). 21. Push button switch according to claim 1, characterized in
that the housing base (3) has projecting locking lugs (36) which protrude into the elongated holes (37) of the push button (2) and interact with them in the sense of a snap-holding mechanism with a stop. 22. Push button switch according to claim 1, characterized in
that in the push button (2) a front window (38) for switching position indication with the help of the pivot position of the switching plunger (4) is left out.

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