EP0553694B1 - Electrical switch - Google Patents

Description

The invention relates to an electrical switch according to the preamble of claim 1 (see DE-A-27 15 063).

Such electrical switches are used to switch electrical devices on and off by pressing them in each case, the actuating element being locked in the respective switching position. In particular, these switches for household appliances such as vacuum cleaners and the like. used.

Such electrical switches have become known from DE-A-27 15 063 and DE-A-22 17 690, the actuating member of which is movably guided in the housing can be brought into two detent positions by means of pressure. In the first latching position, the contact bridges arranged on the actuating member do not touch the normally closed contacts in the housing, so that the switch is in the off position, while in the second latching position, the contact bridges touch the normally closed contacts, with the switch being in the on position.

These electrical switches have a heart-shaped guide curve in which a pin engages in order to determine the locking positions. Another pin engages in another guide curve, whereby the latching positions of the switch are determined by the interaction of the pins and the guide curves.

In the switch shown in DE-A-27 15 063, the further guide curve is designed as an oblique control curve and both guide curves are located on the same side of the housing. The two pins engaging in the guide curves are coupled to one another by means of a connecting element, so that when the actuating member moves, the connecting element can be elastically deformed due to the guide of the pins in the sense of a restoring force on the pin.

A disadvantage of these switches has been found that jamming of the pins in the guide curve can occur when the actuator is tilted. In particular, in the switch shown in DE-A-27 15 063, the connecting element is subjected to bending, which means that a reduction in the restoring force on the pins can occur by wearing out the connecting element after a certain period of use of the switch. In both cases, there is then a risk of missing locking in the on or off position. This unsafe switching behavior in turn means poor operational reliability of the switch in question.

The invention has for its object to develop the switch mentioned so that a secure locking in the on and off position is guaranteed and no switching errors occur.

This object is achieved in a generic switch by the characterizing features of claim 1.

In a further embodiment of the switch according to the invention, the connecting element coupling the two pins engaging in the guide curve consists of a U-shaped bracket which is inserted into a corresponding receptacle in the base of the housing. This makes the switch particularly easy to assemble by first providing the base with the normally closed contacts and inserting the bracket into the receptacle, then placing the actuator with the switch contacts so that the pins on the U-shaped bracket engage in the guide curves and finally that Housing is slipped over the actuator and the base, which snaps into corresponding snap or snap connections on the base. In addition, when using the U-shaped bracket, an additional spring element, which is otherwise required and serves as a connecting element, can be dispensed with.

In a further advantageous embodiment of the invention, the connections for the switch are provided with a U-shaped part which serves as a normally closed contact surface. The U-shaped part is attached to appropriately shaped bars in the base. As a result, the U-shaped part can be arranged in two different positions, so that the connections can optionally emerge from the housing both downwards and to the side.

Still further refinements of the switch according to the invention are contained in the further subclaims.

The advantages achieved by the invention consist in particular in the fact that the switch has a very small overall volume and nevertheless has a very reliable switching behavior which completely excludes switching errors. The actuator is always positioned vertically even in the on position, which prevents jamming with certainty. Due to the connecting element, which couples the pins engaging in the guide curves, there is no need for elaborately shaped bolts and associated slots in the housing for receiving the bolts. Rather, simple pins and connecting elements that can be produced from wire can be selected, so that it is an inexpensive and also easy-to-install switch. The possibility of arranging the connections both downwards and laterally creates a wide range of possible uses for the switch according to the invention, depending on the desired purpose.

Fig. 1

eine Seitenansicht des erfindungsgemäßen Schalters,

Fig. 2

einen Schnitt gemäß der Linie 2-2 in der Fig. 1,

Fig. 3

einen Schnitt längs der Linie 3-3 aus Fig. 2,

Fig. 4

einen Schnitt längs der Linie 4-4 aus Fig. 2,

Fig. 5

einen Schnitt längs der Linie 5-5 aus Fig. 4,

Fig. 6

einen Schnitt längs der Linie 6-6 aus Fig. 4,

wobei die Metallteile zur besseren Veranschaulichung in den Fig. 2 bis 6 ungeschnitten dargestellt sind,

Fig. 7 bis 13

Prinzipskizzen zur Funktionsweise des Schalters in verschiedenen Betätigungsstellungen,

Fig. 14

einen Schnitt durch eine weitere Ausführungsvariante für den Schalter,

Fig. 15

einen Schnitt durch eine nochmals andere Ausführungsform und

Fig. 16

einen Schnitt entlang der Linie 16-16 aus Fig. 15.

An embodiment of the invention is shown in the drawings and will be described in more detail below. Show it

Fig. 1

a side view of the switch according to the invention,

Fig. 2

2 shows a section along line 2-2 in FIG. 1,

Fig. 3

3 shows a section along the line 3-3 from FIG. 2,

Fig. 4

3 shows a section along the line 4-4 from FIG. 2,

Fig. 5

4 shows a section along the line 5-5 from FIG. 4,

Fig. 6

4 shows a section along the line 6-6 from FIG. 4,

the metal parts being shown uncut in FIGS. 2 to 6 for better illustration,

7 to 13

Principle sketches on how the switch works in different operating positions,

Fig. 14

a section through a further embodiment for the switch,

Fig. 15

a section through yet another embodiment and

Fig. 16

a section along the line 16-16 of Fig. 15th

As can be seen from FIG. 1, the electrical switch 1 which can be actuated by pressure and is designed as a two-pole on-off switch and can be latched in the on and off position has a housing 2 and a base 5 which carries the electrical connections 12 4, webs 44 shown in more detail in FIG. 4 are formed with guide grooves, into which corresponding counterparts 45 engage in the interior of the housing 2. As a result, the housing 2 can be pushed onto the base 5 during the assembly of the switch 1 and detachably fastened to the base 5 by means of snap or snap connections known per se. On the housing 2 there is an extension 3, which serves as a guide for an actuator 4.

As can be seen from FIGS. 2 and 3, the actuating member 4 can be moved against the pressure of a spring 6, which is located in a receptacle 7 arranged on the base 5. On the actuator 4, two contact bridges 8 equipped with switch contacts 10 are arranged elastically by means of springs 9. The switching contacts 10 of the contact bridges 8 can be brought into contact with the normally closed contact surfaces 11 of the electrical connections 12 by moving the actuating member 4 when pressure is exerted in the direction of arrow 46 (see FIG. 1), as a result of which an electrical connection between the connections 12 and thus the inputs Position of the switch 1 is made. When the actuator 4 is in the off position of the electrical switch 1 shown in FIGS. 2 and 3, the switching contacts 10 of the contact bridges 8 have a certain distance from the rest contact surfaces 11 due to the spring pressure of the spring 6, so that the electrical connection is interrupted is.

The electrical switch 1 has a detent position in the off and in the on position. The locking position in the off position is determined by the fact that the actuating element 4 with the shoulders 13 rests on corresponding surfaces of the extension 3 inside the housing 2 due to the pressure of the spring 6. In order to fix the other latching position in the on position, two guide curves 14, 15 having different shapes are attached to the actuating member 4 on opposite surfaces that run parallel to the direction of movement.

3 and 5, the first guide curve 14 consists of a surface 16 raised on the actuating member 4, the outer contour of which has the shape of a heart, which is why the surface 16 is also called the switching heart. The second guide curve 15 is formed by a surface 17 recessed on the actuator 4, in the middle of which there is an elevated, triangular surface 18, which can be seen in the comparison of FIGS. 3 and 6. As can further be seen from FIG. 6, the inner contour of the guide curve 15 is essentially heart-shaped.

A pin 19, 20 engages in each of the two guide curves 14 and 15. These two pins 19, 20 are coupled to one another by a connecting element 21. In this exemplary embodiment, the connecting element 21 has the shape of a U-shaped bracket and is inserted in a receptacle 22 on the base 5. As can be seen in the present exemplary embodiment, the pins 19, 20 and the connecting element 21 can be produced in one piece by bending a spring wire. A round cross-section can expediently be selected for the spring wire, but any other cross-sectional shape is also conceivable.

The mode of operation of the switch 1 according to the invention is shown in more detail in FIGS. 7 to 13, in which the guide curve 15 can be seen in plan view and the guide curve 14, which is hidden on the opposite surface of the actuating member 4, is shown in dashed lines. The two pins 19, 20 are through Circles shown, the connecting element 21 is omitted for reasons of clarity.

7 shows the locking position corresponding to the off position. The two pins 19, 20 are located opposite each other in the same position, which is approximately in the central plane of the actuator 4, below the two guide curves 14 and 15. As already mentioned, this locking position is due to the interaction of the spring 6 and the paragraphs 13 with fixed to the housing 2.

If the actuator 4 is moved by pressure in the direction of arrow 46 (see FIG. 1), the pin 19 comes into contact with the guide curve 14, which is formed by the outer contour of the raised surface 16, and becomes corresponding to the obliquely upwardly extending outer contour deflected in the direction of arrow 23. Due to the connecting element 21, the pin 20 is deflected equally and finally, as can be seen in FIG. 8, touches the inner contour of the guide curve 15. Approximately in this position of the pins 19, 20, the switching contacts 10 of the contact bridges 8 come into contact with the normally closed contact surfaces 11 of the electrical connections (see also Fig. 2), whereby the electrical connection is made.

With further movement by pressure on the actuator 4, the pin 20 is then guided along the inner contour of the guide curve 15 essentially vertically upward in the direction of the arrow 24.

At the same time, the pin 19 is deflected a little further in the oblique direction 23 and finally likewise is guided vertically upwards along the outer contour of the guide curve 14 according to the arrow 25. As can be seen from the arrows 24 and 25, the two pins 19, 20 are deflected differently due to the different shape of the two guide curves 14, 15, so that the connecting element 21 is elastically deformed in this movement section. As a result of this elastic deformation, the connecting element 21, which is designed as a U-shaped bracket in the present exemplary embodiment, is subjected to torsion. During this movement, the springs 9 of the contact bridges 8 (see FIG. 2) are tensioned at the same time, since the switch contacts 10 are already resting on the normally closed contact surfaces 11.

The two pins 19, 20 finally reach the position shown in FIG. 9. While the pin 20 is moving there in the direction of the arrow 26 into the upper channel 34, the pin 19, due to the tension caused by the torsion of the U-shaped bracket, snaps back in the direction of the arrow 27 to the deflection corresponding to the pin 20 , because then the forced movement is ended by the guide curve 14. The downward movement of the actuator 4 is finally ended by the stop of the lower surface 35 of the actuator 4 on the base 5 (see also Fig. 5).

In this position, the pressure on the actuating member 4 now decreases, so that it is moved upward again against the arrow 46 of FIG. 1 due to the elastic force of the spring 6. However, due to the tension of the springs 9, this is a concern Switch contacts 10 guaranteed at the rest contact surfaces 11. During this upward movement of the actuating member 4, the pin 19 now comes into contact with the obliquely downwardly extending outer contour of the guide curve 14 and moves along this in the direction of the arrow 28, as can be seen in FIG. 10, until the upper depression 36 in the Guide curve 14 is reached. The pin 20 is carried in a corresponding deflection to the pin 19 by the connecting element 21 and also comes into contact with the triangular surface 18 when the depression 36 is reached by the pin 19. When the upper depression 36 is reached by the pin 19, the electrical switch is located 1 in the second detent position shown in FIG. 11, which corresponds to the on position.

If the electrical switch 1 in the on position is to be switched off, the actuating member 4 is pressed again in the direction of the arrow 46 in FIG. 1, as a result of which the pin 19 along the vertically upwardly extending outer contour of the guide curve 14 in the direction of the arrow 29 is performed, as can be seen in Fig. 11. At the same time, the pin 20 is guided vertically upwards until it abuts against the inner contour of the guide curve 15 and there along obliquely upwards in the direction of the arrow 30. The connecting element 21 is in turn elastically deformed. In the present exemplary embodiment, the U-shaped bracket is subjected to torsion, since the pin 20 is deflected further in the direction of the arrow 30 than the pin 19 guided in the vertical direction 29, as shown in FIG. 12. If the upper point 37 of the guide curve 14 is reached by the pin 19, this snaps due to the Torsional tension in the same position as the pin 20. The electrical connection is still in this position, ie the switch contacts 10 are still in contact with the normally closed contact surfaces 11. At the same time, the movement of the actuator 4 in the direction of arrow 46 in this position is again by contact the lower surface 35 terminated on the base 5.

When the actuating member 4 is released or the pressure on the actuating member 4 is released, the latter moves upward due to the force of the spring 6 and in the opposite direction of the arrow 46 according to FIG. 1. The pin 19 becomes along the outer contour of the guide curve 14 in the direction of the arrow 31 and then moved vertically downwards. At the same time, the switch contacts 10 are lifted off the normally closed contact surfaces 11 (see FIG. 2), the electrical connection being interrupted again. During this movement, the pin 20 is carried in the same position until it finally comes into contact with the inner contour of the guide curve 15 and is moved there obliquely downward in the direction of the arrow 33 according to FIG. 13. Since the pins 19 and 20 are now moved again along the different guide curves 14 and 15, the U-shaped bracket is again subjected to torsion in this movement section, so that the pin 19 along the arrow direction 32 when the lower point 38 of the guide curve 14 is reached snaps into the first latching position corresponding to the off position of the electrical switch 1.

In some cases, such a switch requires a pressure point that is clearly noticeable when it is switched on. This can be realized by the distance between the inner contour of the guide curve 15 and the outer contour of the triangular surface 18 at the constriction lying in the switch-on path through which the pin 20 travels from the detent position corresponding to the off position to the detent position corresponding to the on position 39, which can be seen in more detail in FIG. 6, is the same or slightly smaller than the cross-sectional width or the diameter with a round cross-section of the pin 20. If the pin 20 then reaches the constriction 39, it must be brought through the constriction 39 by means of increased pressure on the actuating member 4. After the pin 20 has passed the constriction 39, a lower pressure is again sufficient for the further movement of the actuating member 4, so that the typical pressure point behavior is present.

As can be seen in more detail in FIGS. 4 to 6, the electrical connections 12 are provided with a U-shaped part 40 which is widened compared to the connection 12, the connection 12 being bent off from one leg of the U. The rest contact surfaces 11 are formed by the other leg of the U's. The U-shaped part 40 is attached to a correspondingly shaped web 41 of the base 5. This makes it possible to attach the U-shaped part 40 so that the connections 12 protrude vertically downward from the housing 2 in order to be connected to the connecting conductor tracks on a printed circuit board by means of plated-through holes. The U-shaped part 40 can also be attached to the web 41 as shown in FIG. 14 can be seen. The connections 12 then protrude laterally at the bottom of the housing 2, which makes this switch particularly suitable for surface mounting on a printed circuit board. In this case, the rest contact surfaces 11 are formed by the base of the U. It should also be emphasized that there is no need for corresponding holes in the housing 2 for the implementation of the connections 12, since these protrude from the switch 1 on the base 5, which closes the housing 2 at the bottom.

A further variant for the electrical connections of the switch 1 can be seen in FIG. These are not cranked connections. The connection 42 consists of a direct extension of a leg of the U-shaped part 43, which is attached to the web 41. Connections 42 designed in this way are particularly simple to manufacture in terms of production technology. As can still be seen in FIG. 16, the connections 42 of this variant have essentially the same width as the U-shaped part 43.

The invention is not limited to the exemplary embodiment described. It is also within the scope of the invention to arrange the two guide curves instead of on the actuating member on the inner surfaces of the housing and the connecting element for the pins on the actuating member. It is important in the exemplary embodiment, however, that the two guide curves have a different shape, as a result of which the connecting element coupling the two pins is elastically deformed in sections during the movement of the actuating member. This elastic deformation creates a force exerted the respective pin, whereby this, as described with reference to FIGS. 7 to 13, is moved in the direction of the switching path, so that incorrect switching is excluded with certainty.

Reference symbol list:

1:

Electrical switch

2:

casing

3:

approach

4:

Actuator

5:

base

6:

Spring (for actuator)

7:

Holder (for spring 6)

8th:

Contact bridge

9:

Spring (on contact bridge)

10:

Switch contact

11:

Resting contact surface

12:

electrical connection

13:

Paragraph (on the actuator)

14, 15:

Leadership curve

16:

raised surface (switching heart)

17:

recessed area (switching heart)

18:

triangular surface

19, 20:

pen

21:

Fastener

22:

admission

23 to 33:

Arrows (direction of movement of the pins)

34:

channel

35:

lower surface (of the actuator 4)

36:

upper depression (of the guide curve 14)

37:

upper point (the guide curve 14)

38:

lower point (the guide curve 14)

39:

Narrowing

40:

U-shaped part (of connector 12)

41:

Footbridge (in base 5)

42:

Connection (further variant)

43:

U-shaped part

44:

Footbridge (at the base)

45:

Counterpart (in housing)

46:

Arrow (according to pressure)

Claims (12)

1. Electrical switch with an actuating member (4) guided to move in a housing (2), for producing an electrical connection, two guide curves (14, 15) of different shape for at least two stop locations being located on surfaces of the switch (1) or of the actuating member (4) extending parallel to the direction of movement of the actuating member (4), in which stop locations engage pins or cams (19, 20) attached to a connecting member (21) and connected to each other by the connecting member (21), which pins or cams cooperate with the guide curves (14, 15) so that the connecting member (21) is elastically deformable on account of the guidance of the pins (19, 20) during the movement of the actuating member (4) in the sense of a restoring force on the pin (19, 20) and that in this case the actuating member (4) can be locked from a switch off position into a switch on position and vice versa, characterised in that the guide curves (14, 15) are located on two opposing surfaces of the actuating member (4) or of the switch housing (2), so that the two pins (19, 20), at the time of movement by the actuating member (4) are deflected to a different extent so that at the time of the elastic deformation, the connecting member (21) is subject to torsion.
2. Electrical switch according to Claim 1, characterised in that the connecting member (21) is constructed as a U-shaped clip, that the pins (19, 20) and the U-shaped clip consist of one piece and that the U-shaped clip and the pins (19, 20) are made from spring wire.
3. Electrical switch according to Claim 2, characterised in that the spring wire has a round cross-section.
4. Electrical switch according to one of Claims 1 to 3, characterised in that the interrupter contact surfaces (11) are located on a base (5), on which webs (44) with guide grooves are integrally formed, in which corresponding counterparts (45) inside the housing (2) engage and the housing (2) is detachably fastened by means of snap-action connections to the base (5).
5. Electrical switch according to one of Claims 2 to 4, characterised in that the U-shaped clip is inserted in a holder (22) in the base (5).
6. Electrical switch according to one of Claims 1 to 5, characterised in that the first guide curve (14) consists of a raised surface (16) on the actuating member (4), whereof the outer contour is heart-shaped and the second guide curve (15) consists of a recessed surface (17) in the actuating member (4), whereof the inner contour is essentially heart-shaped.
7. Electrical switch according to Claim 6, characterised in that a raised triangular surface (18) is located in the centre of the recessed surface (17) of the guide curve (15).
8. Electrical switch according to Claim 7, characterised in that for producing a pressure point for the switching-on operation between the outer contour of the triangular surface (18) and the inner contour of the guide curve (15), a constriction (39) lying in the switching-on path is provided, whereof the spacing is equal to or slightly less than the cross-sectional width of the engaging pin (20).
9. Electrical switch according to one of Claims 4 to 8, characterised in that the interrupter contact surfaces (11) are formed by a leg of a U-shaped part (40, 43), the electrical connection (12, 42) projecting from the other leg of the U-shaped part (40, 43) and the U-shaped part (40, 43) being fitted on correspondingly shaped webs (41) of the base (5).
10. Electrical switch according to Claim 9, characterised in that the electrical connection (42) extends in the direction of the leg of the U-shaped part (43).
11. Electrical switch according to Claim 9, characterised in that the electrical connection (12) is bent from the leg of the U-shaped part (40).
12. Electrical switch according to one of Claims 9 to 11, characterised in that the connections (12, 42) on the base (5) project from the housing (2).

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