EP0980577A1

EP0980577A1 - Switching arrangement

Info

Publication number: EP0980577A1
Application number: EP98933440A
Authority: EP
Inventors: Rainer Kizele; Heinrich Müller; Klaus Rapp
Original assignee: Marquardt GmbH
Current assignee: Marquardt GmbH
Priority date: 1997-05-07
Filing date: 1998-05-05
Publication date: 2000-02-23
Anticipated expiration: 2018-05-05
Also published as: EP0980577B1; DE59803282D1; US6204459B1; DE19817369A1; WO1998050930A1

Abstract

The invention relates to a switching arrangement (1), specially for household appliances such a washing machines, dishwashers or the like,. The switching arrangement (1) has one housing (2) comprising at least one switching element (11, 11') which is arranged inside (16) said housing. At least one actuating member (5, 6) is disposed on the housing (2) to actuate the switching element (11, 11'). The housing (2) also comprises a support section (14) with a receiving part (15, 15') for the actuating member (5, 6). The receiving part (15, 15') in the support section (14) has an opening (17), which is allocated to the switching element (11, 11'), on the side facing the inside (16) of the housing. An elastic sealing element (18) is arranged on the opening (17) in the support section (14) between the switching element (11, 11') and the actuating member (5, 6) in the direction of movement of the actuating member (5, 6). The actuating member (5, 6) acts upon the switching element (11, 11') by means of the elastic sealing element (18). The sealing element (18) is injection molded onto the support section (14) in the form of a two-component part.

Description

ARRANGEMENT OF SWITCHES

The invention relates to a switch arrangement with at least one switching element and an actuator according to the preamble of claim 1.

Such switch arrangements are used for the selection of functions of electrical devices by the user. These electrical devices can be domestic appliances such as washing machines, dryers, dishwashers or the like.

Such a switch arrangement with a housing is known from DE 195 03 702 AI. In the interior of the housing there is an all-round encapsulated and sealed inner housing in which switching elements are arranged. Actuating elements are arranged on the housing for actuating action on the switching elements. The inner housing has a membrane-shaped wall which is arranged between the switching elements and the actuators. The actuators act on the switching elements via the membrane-shaped wall which is elastic in the direction of movement of the actuators.

The membrane-shaped wall on the inner housing thus acts as an elastic sealing element between the actuating member and the switching element, which prevents the ingress of pollutants, such as water, dust or the like, into the interior of the switch arrangement. However, the manufacture of the inner housing is very complex. In addition, the switching elements must already at Manufacturing process for the inner housing can be introduced into this. A subsequent change in the number of switching elements is no longer possible. It has therefore been found to be disadvantageous that the known switch arrangement is not very flexible and cannot be easily adapted to different device configurations.

The invention has for its object to design a switch arrangement such that a flexible adaptation to different device configurations is possible in a simple manner and yet a damaging effect of pollutants on the switching elements is avoided.

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

Further embodiments of the invention are the subject of the dependent claims.

In particular, it is preferred to inject a snap disk serving as a switching element in the manner of a two-component part directly onto the receptacle for the actuating member in the carrier part. As a result, the switching element itself acts as a sealing element, so that both the switching function and a seal can be implemented by means of a single element. An advantageous further development also consists in injection molding an all-round seal for lateral sealing of the space accommodating the switching elements in the manner of a two-component part on the carrier part. This can be done in the same tool during the injection molding of the snap disks if the same material as the snap disk is used as the material for the sealing lip. Despite the reduction in the number of parts, an excellent seal is guaranteed. In a further particularly advantageous embodiment, light guides are integrated in the carrier part. The carrier part which serves to hold the actuating members is then preferably produced from optically transparent plastic. The carrier part can thus be used at the same time for the transmission of light for functional lighting or the like of the actuators. Finally, it is also expedient to provide the side of the housing facing the carrier part with conductor tracks, for example as a MID (Molded Interconnected Device) part. The conductor tracks serve as fixed contacts for the snap disks and for establishing the required electrical connections for the switching elements.

A switch arrangement with the mentioned further developments essentially consists of two parts. The first part is the housing with the conductor tracks, which serves as the main body for the switch arrangement. The second part serves as a carrier part for the actuators and is provided as a two-component part with integrated snap disks, seals and light guides. The second part is then attached to the first part like a cover by snap connections, snap hooks or the like. Then this arrangement can also be provided with a covering panel through which the actuating members protrude. It is immediately apparent that the simple structure and the small number of parts result in a simplified assembly of the switch arrangement.

The advantages achieved by the invention are, in particular, that the space accommodating the switching elements of the switch arrangement is easily sealed at all openings and connection points against the ingress of water, dust or the like. is so that the switching elements are protected from damaging influences. This significantly improves the risk of premature failure of the switch arrangement, even under difficult operating conditions.

In addition, different variants of switch arrangements can be produced by the support part being provided for the maximum number of actuating elements and switching elements, but during assembly being equipped only with the actuating elements and / or switching elements actually required for the respective variant. This simplifies storage and the switch arrangement is generally less expensive. In addition, an increased functionality is achieved in the switch arrangement according to the invention with a simultaneous reduction in the number of parts compared to previous solutions.

Embodiments of the invention are shown in the drawings and are described in more detail below. Show it

1 is a plan view of a switch arrangement,

Fig. 2 shows a section along the line 2-2 in Fig. 1 and

Fig. 3 shows a section as in Fig. 2 according to another embodiment.

1 shows a top view of a switch arrangement 1 for an electrical household appliance, which is, for example, a washing machine or a dishwasher. The switch arrangement 1 has a housing 2 which is provided with an aperture 3 on the upper side. Actuators 4, 5, 6, 7, which are arranged on the housing 2, protrude through the cover 3 in a manually accessible manner, with the help of which the user can select various functions of the electrical household appliance. Also located in the panel 2 is a display 8, for example an LED or LCD display, in which the operating states of the domestic appliance are visualized for the user.

2, there are switches 9, 10 and switching elements 11, 11 "assigned to the actuators 4, 5, 6, 7 in the housing 2. Switch 9 is a mains switch for switching the domestic appliance on and off The switch 10 is a rotary switch with the aid of which the respective program of the household appliance can be adjusted. The actuating members 5, 6 ultimately serve to select various functions of the domestic appliance. The actuating member 6 consists of a button 12 and a plunger 13 and acts actuating the associated switching element 11. The actuating element 5 consists of a rocker 12 'which can be moved in two directions and acts on two switching elements 11, 11.' For example, in a washing machine, the actuating element 5 can be used to increase or decrease the temperature and by means of the Actuator 6, the execution of an additional pre-wash can be selected.

The housing 2 has a carrier part 14, which is preferably arranged in the housing interior 16 as a type of cover. Of course, the carrier part 14 can also be a component of the housing 2 or can also be formed in one piece with the housing 2. The carrier part 14 has approximately pot-shaped receptacles 15 for the actuators 5, 6. For example, the plunger 13 is movably mounted in the receptacle 15 in its longitudinal direction. The receptacle 15 in the carrier part 14 has an opening 17 on the side facing the housing interior 16 which is assigned to the respective switching element 11, 11 '. At the opening 17 in the carrier part 14 is in the direction of movement of the actuator 5, 6 elastic, in sealing element 18 configured in the manner of a membrane, so that the actuating element 5, 6 acts on the switching element 11, 11 'via the elastic sealing element 18. Thus, the housing interior 16 is sealed from the outside by the membrane-shaped sealing element 18 arranged between the switching element 11, 11 'and the actuating element 5, 6, with the result that penetration of pollutants, such as water, dust or the like, into the housing interior 16 is effectively prevented .

The carrier part 14, like the housing 2, is made of a hard plastic. It is preferably a thermoplastic, such as polyacrylate, polyamide or the like, so that the carrier part 14 and / or the housing 2 can be produced by injection molding. The sealing element 18 is molded onto the carrier part 14 in the manner of a two-component part, with a cohesive connection between the edge at the opening 17 and the sealing element 18. It is advisable to choose an elastic plastic, such as a thermoplastic elastomer, as the material for the sealing element 18, which enters into a good adhesive connection with the plastic for the carrier part 14. A block copolymer of polybutylene terephthalate and polyether glycol has proven to be particularly suitable as the thermoplastic elastomer.

In the housing 2 there is a circuit board 19 containing the electrical connections for receiving the switching elements 11, 11 '. It is advisable to also arrange the power switch 9 and the rotary switch 11 on the circuit board 19. The circuit board 19 can be a conventional circuit board. However, the circuit board 19 is preferably designed as a part of the housing 2 in the manner of a MID part. A MID (Molded Interconnected Device) part is an injection-molded plastic part with conductor tracks on it, so that the MID part is like a circuit board for receiving serves electrical and / or electronic components.

In the present case, the circuit board 19 is produced in one piece with the housing 2 using injection molding technology, specifically as a housing end part on the underside of the housing 2 assigned to the switching element 11, 11 '. As already stated, on the opposite side is on the top side assigned to the actuating member 5, 6 of the housing 2, the panel 3. The side of the housing end part containing the electrical connections for the circuit board 19 faces the housing interior 16. The switching element 11, 11 'fastened on the circuit board 19 is designed as a snap disk, switch cap or contact element made of plastic, such as a thermoplastic elastomer. Such a snap disc, which is provided with a bridging contact, is known for example from DE-OS 41 12 754. On the circuit board 19 there are contact surfaces serving as fixed contacts and in contact with the conductor tracks, with which the bridging contact in the snap disk interacts to make contact when the plunger 13 acts on the snap disk via the sealing element 18. Of course, the conductor tracks themselves can also serve as fixed contacts.

Furthermore, an electronic circuit 20 for evaluating the switching signals generated by the switching elements 11, 11 'and optionally by the rotary switch 10 is located on and / or in the housing 2. The electronic circuit 20 is located on a circuit board 22 fastened to the circuit board 19 serving as the housing end part by means of snap hooks 21. The electronic circuit 20 can additionally convert the switching signals into corresponding electrical signals, such as bus signals or the like. The electrical signals are then transmitted between the electronics via an interface electronics arranged in the electronic circuit 20 electronic circuit 20 and other components, such as a microcomputer or the like, in the household appliance.

The carrier part 14 is fastened by means of snap hooks 23 or similar locking elements in the housing 2, specifically there on the circuit board 19. The switching elements 11, 11 'are located in the interior 16 of the housing, specifically in the space 24 between the carrier part 14 and the circuit board 19. At the openings 17, this space 24 is sealed by the sealing elements 18. At the edge of the carrier part 14 there is an essentially all-round elastic sealing lip 25 which laterally seals the space 24. The sealing lip 25 also consists of a thermoplastic elastomer, such as the block copolymer mentioned above, and is in turn molded onto the carrier part 14 in the manner of a two-component part. With the free surface, the sealing lip 25 abuts the circuit board 19. If necessary, an elevated edge 40, as can be seen in FIG. 3, can be formed on the circuit board 19 as a counter stop surface. This prevents the penetration of pollutants into the space 24 and the switching elements 11, 11 '. It should be emphasized that in the area of the power switch 9 and the rotary switch 10, such a seal 26 on the carrier part 14 for sealing the bushings from the actuator 4, 7 can be molded into the interior 16 of the housing.

As can be seen further with reference to FIG. 2, individual receptacles 15 ′ can be present in the carrier part 14, in which the actuating element and the associated switching element are missing. In this way, different variants of switch arrangements 1 can be produced by the carrier part 14 with receptacles 15, 15 'for the maximum number of

Actuators 5, 6 and the circuit board 19 are provided for equipping with the maximum number of switching elements 11, 11 '. During assembly, the carrier part 14 and the circuit board 19 but only equipped with the switching elements 11, 11 'and actuators 5, 6 actually required for the respective variant, and then provide the housing 2 with the cover 3 corresponding to the desired variant. Since only one carrier part 14 is required for all variants, considerable cost savings can be achieved. It should be emphasized that the empty receptacles 15 'are also provided with a sealing element 18, so that penetration of pollutants into the space 24 is excluded at these points.

Another embodiment of the invention is shown in FIG. 3. Here, the snap disk 34 serving as switching element 11, 11 'is molded directly onto the opening 17 of the receptacle 15 in the manner of a two-component part. The snap disk 34 consists of a base part 35 arranged on the circuit board 19 and a cover 36 connected to the base part 35 via a lateral surface 37 and protruding into the opening 17. The actuating member 5, 6 acts via the plunger 13 on the cover 36 for actuating the snap disk 34. A spring-like, elastic connecting element 38 is preferably connected in one piece to the edge of the base part 35 and on the other hand to a fastening element 39. Distance tolerances to the board 19 are compensated for by the connecting element 38.

The fastening element 39 is injection molded on the edge of the opening 17, specifically on the side facing the housing interior 16. Again, in addition to the injection molding of the snap disk 34 together with the fastening element 39 and the connecting element 38, the sealing lip 25 can also be injection molded at the same time. The flow channels 41 used in the injection molding in the carrier part 14 for the plastic for the production of the snap disk 34 and the sealing lip 25 are in section in FIG. 3 on the side facing the diaphragm 3 see. The snap disk 34, including the connecting element 38 and the fastening element 39, made of a thermoplastic elastomer, such as the block copolymer specified above, then acts simultaneously as a sealing element, so that the separate sealing element 18 can be dispensed with. Here, too, receptacles 15 'not occupied by actuators can also be provided with molded-on snap disks 34 for the simple production of variants.

The carrier part 14 is preferably designed as a multifunctional part which, on the one hand, holds the actuating members 5, 6 as described above and, on the other hand, serves to transmit light, which is generated by lighting elements 27 in the interior 16 of the housing, to the outside of the housing 2. For this purpose, as can be seen in FIG. 1, windows 28 can be arranged on the outside of the housing 2, for example on the cover 3. A lighting up of the lighting element 27 can signal, for example, the actuation of the corresponding actuating member 5, 6.

As can be seen from FIG. 2, the required lighting elements 27, for example light-emitting diodes, are arranged in the housing 2 on the circuit board 19. To transmit the light, a light guide rod 29 assigned to the luminous element 27 is integrated in the carrier part 14 and points in the direction of the diaphragm 3. In particular, it is preferred to integrally integrate the light guide rod 29 into the carrier part 14. For this purpose, the carrier part 14 consists of a plastic that is largely transparent to light in the visible region. The carrier part 14 then has a first region 30, which runs essentially parallel to the circuit board 19, and a second region 31, which is approximately perpendicular to the first region 30. The first area 30 contains the receptacles 15, 15 'for the actuators 5, 6, while the second area 31 as actual light guide rod 29 is used. As a result, the light from the luminous element 27 is guided via the carrier part 14 essentially towards the outside of the housing 2.

In order to prevent the light generated by the lighting element 27 from being weakened, the transition 32 between the first region 30 and the second region 31 is now designed such that the light guided in the second region 31 essentially does not pass into the first region 30 is. For such a design of the transition 32, constrictions 33, depressions or the like are available, for example. It is thereby achieved that the light in the light guide rod 29 is guided to the diaphragm 3 and cannot or only to a small extent spread laterally on the optically transparent carrier part 14.

The invention is not restricted to the exemplary embodiments described and illustrated. Rather, it also includes all professional training within the scope of the inventive concept. Thus, the invention can also be used on switch arrangements for machine tools, motor vehicles, keyboards or the like.

Reference symbol list:

1: switch arrangement

2: housing

3: aperture

4: actuator (for rotary switch)

5, 6: actuator (button, rocker)

7: actuator (for power switch)

8: display

9: power switch

10: rotary switch

11.11 ': switching element

12: key

12 ': seesaw

13: pestle

14: carrier part

15: Recording

15 ': recording (unoccupied)

16: housing interior

17: opening

18: sealing element

19: circuit board

20: electronic circuit

21: snap hook (for printed circuit board)

22: PCB

23: snap hook (for carrier part)

24: space (to accommodate the switching elements)

25: sealing lip

26: seal

27: light element

28: window 29 light guide rod 30 first area (from support part) 31 second area (from support part) 32 transition (between first and second

Area)

33 constriction 34 molded snap-on washer 35 base part 36 cover 37 lateral surface 38 connecting element 39 fastening element 40 raised edge (on circuit board) 41 flow channel (in the carrier part)

Claims

Claims:

1. Switch arrangement, in particular for domestic appliances such as washing machines, dryers, dishwashers or the like, with a housing (2), with at least one switching element (11, 11 ') located inside the housing (16), with at least one on the housing (2 ) arranged actuating member (5, 6) for actuating action on the switching element (11, 11 '), ^{and arranged} with a sealing of the housing interior (16) between the switching element (11, 11') and the actuating member (5, 6) , in the direction of movement of the actuating member (5, 6) elastic sealing element (18), the actuating member (5, 6) acting via the elastic sealing element (18) on the switching element (11, 11 '), characterized in that the housing (2 ) has a carrier part (14), in particular arranged in the interior of the housing (16), which has a receptacle (15, 15 ') for the actuating member (5, 6), that the receptacle (15, 15') in the carrier part (14) on the inside of the housing (16) facing an opening tion (17), which is assigned to the switching element (11, 11 '), that the sealing element (18) is attached to the opening (17) in the carrier part (14), and that the sealing element (18) in the manner of a two -Component part is molded onto the carrier part (14).

2. Switch arrangement according to claim 1, characterized in that the switching element (11, 11 ') is designed as a snap disk made of plastic, preferably the switching element (11, 11') on an in the housing (2) containing electrical connections The circuit board (19) is arranged such that, in particular, the snap disk serving as switching element (11, 11 ') is provided with a bridging contact and with fixed contacts cooperates, the fixed contacts preferably being arranged on the circuit board (19), in particular in the manner of conductor tracks.

3. Switch arrangement according to claim 1 or 2, characterized in that the snap disk (34) serving as switching element (11, 11 ') serves as a two-component part directly at the opening (17) of the receptacle (15, 15' ), in particular on the side of the housing (16) facing the preferably pot-shaped receptacle (15, 15 '), so that the snap disk (34) simultaneously acts as a sealing element.

4. Switch arrangement according to claim 1, 2 or 3, characterized in that the receptacle (15, 15 ') can be equipped with an actuating member (5, 6) as required, and that the opening (17) of an unequipped receptacle (15') is provided with a sealing element (18) molded on in the manner of a two-component part and / or with a snap disk (34) molded on directly in the manner of a two-component part.

5. Switch arrangement according to one of claims 1 to 4, characterized in that the carrier part (14) by means of snap hooks (23) or the like. In the housing (2), in particular on the circuit board (19) is attached, and that preferably on Carrier part (14) is a substantially all-round elastic sealing lip (25), which is injection molded in particular in the manner of a two-component part on the carrier part (14), the sealing lip (25) containing the switching element (11, 11 ') (24) seals laterally between the carrier part (14) and the circuit board (19) inside the housing (16).

6. Switch arrangement according to one of claims 1 to 5, characterized in that the sealing element (18) and / or the Sealing lip (25) and / or the snap disc (34) made of an elastic plastic, in particular a thermoplastic elastomer, such as a block copolymer made of polybutylene terephthalate and polyether glycol, and that preferably the carrier part (14) and / or the housing (2 ) consist of a hard plastic, in particular a thermoplastic, such as polyacrylate, polyamide or the like.

7. Switch arrangement according to one of claims 1 to 6, characterized in that the housing (2) on the switching element (11, 11 ') associated with the underside with a housing end part and on the actuating member (5, 6) associated with the top with an aperture (3) is provided, the actuating member (5, 6) projecting through the cover (3) for its manual access, and that preferably the side of the housing end part facing the housing interior (16) as a board (19) in the manner of a MID ( Molded Interconnected Device) part is formed.

8. Switch arrangement according to one of claims 1 to 7, characterized in that on or / and in the housing (2) an electronic circuit (20) for the evaluation of the switching element (11, 11 ') generated switching signals or the like. serves, in particular is located on a printed circuit board (22) attached to the housing end part, an interface electronics for the transmission of electrical signals possibly being arranged on the printed circuit board (22).

9. Switch arrangement according to one of claims 1 to 8, characterized in that at least one lighting element (27) is arranged in the housing (2), in particular on the circuit board (19), and that preferably a light guide rod (29) assigned to the lighting element (27) ) is arranged in the carrier part (14) such that the light from the lighting element (27) in substantially in the direction of the outside of the housing (2), for example to a window (28) located in the panel (3).

10. Switch arrangement according to claim 9, characterized in that the carrier part (14) consists of a largely transparent to light in the visible region plastic, so that light from the lighting element (27) via the carrier part (14) to the outside of the housing (2) is passed, and that the light guide rod (29) in the carrier part (14), in particular in one piece, is integrated.

11. Switch arrangement according to claim 9 or 10, characterized in that the carrier part (14) has a first region (30) which is arranged substantially parallel to the circuit board (19) and a second region (31) which is approximately perpendicular to first area (30) is that the first area (30) contains the receptacle (15, 15 ') for the actuating member (5, 6), and that the second area (31) serves as a light guide rod (29), in particular the Transition (32) between the first and the second area (30, 31) is formed, for example by constrictions (33), depressions or the like, that the passage of the light guided in the second area (31) into the first area ( 30) is essentially prevented.