DE8911621U1 - KEY SWITCH - Google Patents

Description

PATENT ATTORNEYS. JESSENSTRASSE 4 · D-2000 HAMBURG 50 · TEL. (040) 3893501 · FAX 3893502 · TELEX 2166426 pahn d

DIPL-PHYS. OLE NIEDMERS DIPL-ING. HANS W. SCHÖNING EUROPEAN PATENT ATTORNEYS

Dip],-Ing, Koifyäpg ?riesemutb _; Psstkassp 13, 2210 öreiter^urg-H&rdoe

Push button switch
Description o

The invention relates to a pushbutton switch with a housing, a projection for fastening the switch, a pushbutton plunger which can be moved in a substantially axial direction from an outer end position into the housing to an inner end position and out of this Q and in doing so opens at least one switch contact arranged inside the housing, whereby the pushbutton plunger is held at a reducible distance from the location at which the switch contact, one part of which is designed as a contact disk, is opened by a first compression spring on the one hand, and on the other hand by a second compression spring arranged between the one pushbutton plunger end located in the housing and the bottom area of the housing facing away from it, enclosing the contact disk between

COMMERZBANK AG, BLZ 200400pU",.NR/,>6/j)60Ct1 -!DBUTSCHGBANK AG, BLZ 20070000, NR. 6565675 POSTGIRCTHAMBURG. fflS^OOlOOW.'flR. 13048-205

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is held in its outer end position by both compression springs.

I A pushbutton switch of this type is known (DE-OS 36 29 I 550), The well-known push button is successfully used in

'£ Automotive construction and serves as

§ Switch for closing an electrical circuit when

i for example opened the doors of a motor vehicle

% and as a result of the opening of the vehicle door a light

S or another electrical consumer in the passenger compartment I room or otherwise*") should be switched on. Switch I -. of this type are generally used in the field of motor

^ vehicle door and, due to their long-stroke design, are able to easily accommodate production-related tolerances between the door and the door frame of a

&lgr; motor vehicle so that switch extension

f; additional constructions are not required.

p However, it has been found that the well-known door switch

I states that due to his previous switch contact

iv training contact difficulties not in all cases

. can be excluded, since the individual parts of the

i Pushbutton switches and thus also the actual switch

'■' contacts in the push button switch as mass-produced

, "\ stamped parts are manufactured and thus production-related tolerances occur, which sometimes lead to the contact difficulties mentioned when carrying out the switching process.

It was observed that in particular the movable switch contact, which was designed as a separate contact disk, performed a pendulum movement when switching or wobbled in relation to the direction of the switching axis when the pushbutton of the pushbutton switch moved.

I I t I · # · ·

It is the object of the present invention to create a pushbutton switch of the type mentioned at the beginning, which can perform its switching function even more reliably over a longer operating period than the known pushbutton switch and which can be manufactured very cost-effectively as a mass product for installation in motor vehicles.

The object is achieved according to the invention in that 7wjcr the first compression spring and the contact disk a support element is arranged.

The advantage of a pushbutton switch designed in this way is essentially that the support element, which is acted upon by the compression spring, keeps the contact disk with its surface essentially constantly at right angles to the displacement axis, so that a pendulum or wobbling movement, as was sometimes observed with the known pushbutton switch, no longer occurs. The advantage according to the invention is that the contact reliability of the pushbutton switch is significantly increased, as intended.

In an advantageous design of the pushbutton switch, the support element rests essentially at a point on the contact disk, i.e. the support element is designed in such a way that it can only act on the contact disk at a point. This ensures that force components directed away from the direction of the displacement axis, caused by manufacturing-related tolerances of the compression spring, the contact disk and the other components of the pushbutton switch, cannot occur again and a maximum level of contact reliability is achieved.

It is also advantageous to arrange a support element between the second compression spring and the contact disk, so that any force components originating from the second compression spring that do not act parallel to the direction of the displacement axis of the touch plunger are excluded.

Basically, the support element in the transverse

SCriill n jcue ucilculji ycclynctc &Ggr;&Ogr;&Ggr;&idigr;&Ggr;&igr; flauen KdHII, Üffl to fulfill the task described above. It can be advantageous, for example, to design the support element to be mushroom-shaped in cross section, with the stand or stem of the mushroom being inserted into the end of the coiled compression spring and held there in a centered manner. The cover or the mushroom head is applied to the contact disk. It is therefore advantageous, regardless of the type of other structural design of the support element, to design it raised at least on the side facing the contact disk in order to create a surface that ensures the smallest possible contact surface towards the contact disk.

In a very advantageous design of the pushbutton switch, the support element has a cross-section that is almost lens-shaped, whereby such a lens-shaped support element is essentially rotationally symmetrical and thus, which makes assembly absolutely problem-free, cannot be installed incorrectly under any circumstances, which can happen, for example, with the support elements with a mushroom-shaped cross-section described above and has already been observed in reality.

In order to ensure in all cases that the compression spring or compression springs continuously exert their force on the support element in the direction of the displacement axis of the touch plunger and that the support element cannot be displaced away from the displacement axis or that its own axis is positioned at an angle to the displacement axis, the support element advantageously has a circumferential, plate-shaped QS nöfiu aiii, u c �Ggr; "&igr;&idigr;&idigr;&idigr;&iacgr;&eegr;&Ogr;&Ggr;&igr;«.&igr;8&Ggr;&ngr;£&Ggr;&iacgr; cliStSnu u c S &eegr; ü &igr;&igr; 6 y c c &igr;&thgr; ments is essentially aligned parallel to the contact disk. This creates a recess in the area of the plate-shaped edge and the lens-shaped elevation that is essentially circular when viewed from above onto the support element, against which the end of the compression spring or its opening can rest in a fixed manner. This applies equally to both the first compression spring resting on the support element and the second compression spring engaging on the support element that may be provided further.

The support element itself is preferably made of plastic and can, for example, be manufactured fully automatically and therefore inexpensively in an open injection molding machine. The material of the support element is preferably polyamide, but any other suitable plastic materials can also be used to form the support element, whereby the support element can also be made of metal in certain applications if conductive properties of the support element are required.

If the support element is made of plastic, it can advantageously be reinforced with glass fibre to increase its strength.

The invention will now be described with reference to the following schematic drawings using an exemplary embodiment. In them:

Fig. 1 shows a sectional side view of a pushbutton switch with the pushbutton plunger in the upper end position,

Fig. 2 shows a detail of the illustration in Fig. 1 in section in an enlarged view,

Fig. 3 a side view of a support element with a lens-shaped cross section with a surrounding edge and

Fig. 4 is a plan view of the lens-shaped support element according to Fig. 3 in detail.

The pushbutton switch 10 essentially consists of a housing 11, a fastening projection 12, a pushbutton plunger 13 and the switch contact 17 - and a switch contact designed as a contact disk 16, which are arranged in the housing 11. In the embodiment described here, the pushbutton switch 10 consists of a tubular housing 11, which has an essentially square cross-section. The housing 11 and the fastening projection 12 are formed in one piece, with the fastening projection 12 being designed as a flat web and arranged essentially at right angles to the longitudinal direction of the housing. The longitudinal direction of the housing essentially corresponds to the displacement axis 25 of the pushbutton plunger 13.

The touch plunger 13 is formed by a touch plunger hole 130 corresponding to its cross-sectional shape, which

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in the fastening projection 12. The touch plunger hole 130 can be shaped in any suitable way according to the cross-sectional shape of the touch plunger 13. The touch plunger 13 has a projection 131 with which it rests on a projection 120 formed accordingly in the fastening projection 12 when it has reached its outer end position 14. For the sake of clarity, the outer end position 14 of the touch plunger 13 is displaced parallel to its outer end 21, the touch plunger 31 has another axial end 21 located in the housing 11, which can be displaced into the housing 11 up to a stroke position 15, see the line shown in Fig.

The displacement axis 25 also essentially represents the housing axis. At the lower end of the housing 11, which is formed by the end facing away from the fastening projection 12, an opening is formed which forms the bottom area 23 of the housing 11. In the embodiment shown here, the bottom area 23 is closed by a housing projection which can be inserted into the housing end 26 and which has a cross section which is essentially designed to correspond to the cross section of the housing 11. The housing projection 27 closes the housing 11 at the housing end 26. The housing projection 27 has locking devices 28 which engage in corresponding locking openings 29 which are arranged in the housing end 26. For this purpose, at least the housing projection 27 is made of elastically deformable material, so that the housing insert 27 with its elastic locking devices 28 can be pushed into the housing end 26, whereby in the end position shown in Fig. 1 the locking devices 28 then move radially away from the displacement axis 25 and assume the end positions shown there. The

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Housing insert 27 also has a finger-like projection 30 which projects into housing 11 essentially in the axial direction, i.e. in the direction of displacement axis 25, and by means of which compression spring 21 is guided.

lüs state of the closed switching contact, the contact tongues of the switch contact 17 are in contact with the contact disk 16, see Fig. 1, which shows the closed position of the switch contact. The contact disk 16, which forms one part of the switch contact, is in the

- essentially radial to the displacement axis 25 and is held at a distance or in the position of the closed switch contact by the compression spring 24 on the one hand, which is supported on the other side on the bottom of the housing 27 and on the finger-like projection 30 there. In addition, the contact disk 16 is supported in the axial direction on the one hand by a second spring device 19, which is also formed axially to the displacement axis 25 and which is supported on the other hand in an axial recess 132 formed on the touch plunger end 20 on the recess bottom 133 there. Between the ends of the compression springs 19, 24 adjacent to the contact disk 16

&zgr; A support element 160 is inserted between each one.

In the embodiments shown in Fig. 1 and 2, the support element 160 consists of a mushroom-shaped body, with the head or the hood of the mushroom resting on the contact disk 16, while the stem of the mushroom (not shown separately here) projects into the adjacent opening of the compression spring 19 or 24 and is held there in a centered and fixed manner.

Another embodiment of the support element 160 is shown in Fig. 3, this support element having a substantially lens-shaped cross-section which is just as rotationally symmetrical as the mushroom-shaped support element to the axis 164 of the support element 160. The axis 164 is, in the state installed in the pushbutton switch 10 (cf. Figs. 1 and 2), aligned or identical (axis!) with the displacement axis 25. The support element 160 shown in Figs. 3, 4 also has a circumferential, plate-shaped edge 163 which, in the assembled state of the support element 160, is substantially... parallel to the contact disk *6, ie its transverse axis 165 is essentially parallel to the surface of the contact disk 15. The plate-shaped edge 163, in conjunction with the lens-shaped or otherwise shaped elevation of the support element 160, forms a recess which receives the open end of the compression spring 19 or 24 (see the dot-dash line in Fig. 3) and keeps it centered. The support element 160 allows essentially point-like contact with the contact disk 16.

The contact disk 16 can thus be acted upon in the axial direction from one side by the compression spring 19 and from the other side by the compression spring 24, the axial stroke that the compression spring 19 can execute being limited by the distance between the support surface, which is formed by the inner end of the touch plunger, and the contact disk 16 when the contact disk 16 is in the outer end position, i.e. in the state shown in Fig. 1.

This design measure ensures that the sensing plunger 13 between its outer end position 14 and the location 18 to which the contact disk 16 is

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13

Switch contact 17 is lifted and corresponds slightly below the displacement point of the contact disk 16 shown in Fig. 1 and 2, a predetermined displacement path, i.e. a so-called 2 dead path, can be carried out. By appropriate spacing

μ of the end 20 of the probe 13 from the contact disk

H 16 can be used to provide a predetermined dead travel, which

f can be, for example, 1 mm long.

f Both compression springs 19, 24 are made of spring steel wire

fr according to DIN 2076. The set spring constants of both

;■ -. Compression springs 19, 24 allow that during a movement

I of the plunger 13 into the housing 11 first the

| ^? Compression spring 19 to overcome the dead travel

Yi The axial stroke of the plunger 13 in

K Direction of the displacement axis 25 is so long that in

I essentially the entire pushrod 13 in the housing 11

fi is recorded when the inner end position 15 of the

p pushbutton 13 has been reached. If the pushbutton

?; 13 from the closed circuit shown in Fig. 1

i' terkontaktstellung pushed in, is after

; Passing through the dead path of the contact between the

; contact disk 16 and the fixed switch contact 17

H immediately after completion of the dead path

- ■) interrupted and kept in an interrupted state independently of the stroke positions following in the direction of movement to the inner end position, i.e. the contact between the contact disk 16 and the switch contact 17 is interrupted in all possible stroke positions of the push rod 13. The switch contact 17 consists of two contact tongues not shown separately here, which rest against the contact disk 16 in the previously described state of the closed switch contact. The contact tongues themselves (not shown) are each made in one piece with a contact plug 36

designed, the contact tongues extending essentially 1m inside the housing 11 opposite one another up to the housing insert 27 and there emerging from the housing 11 with their contact plugs 36. The contact plugs 36, of which only one is shown here, can in principle be designed in any way, but they are preferably designed in such a knife-like manner that the cable lugs usually used in motor vehicle construction can be plugged onto them.

In the fastening attachment, which in the embodiment of the pushbutton switch 11 shown here is arranged asymmetrically to the displacement axis 25 of the housing 11, i.e. protrudes from the housing 11 on one side, a fastening hole 37 is formed which runs essentially parallel to the displacement axis and with which the pushbutton switch 10 can be fastened, for example, in the area of a motor vehicle door or the like. The fastening hole 37 is designed as a countersunk hole with a conical cross-section, so that screw heads are essentially flush with the outer surface of the fastening attachment 12. The fastening hole 37 is at least partially provided with an insert 38 made of electrically conductive material, which can be connected to another switch contact 39 or can also be identical to the switch contact 17. The electrically conductive insert 38 is also conical or trapezoidal in shape, corresponding to the cross section of the countersunk hole, so that a screw with its head in the countersunk hole creates an electrical connection, for example with a motor vehicle chassis, on which the pushbutton switch 10 is attached.

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The housing H ₁ , the housing insert 27, the fastening projection 12 integrally connected to the housing 11 and the touch plunger 13 are made of a suitably moldable material, for example a plastic such as polyamide or the like, which may be glass fiber reinforced. The same applies to the support element 160, which is enclosed between the compression springs 19, 24 and the contact disk 16.

The contact disk 16 is preferably made of a brass alloy, as are the switch contacts 17, which are here connected in one piece with the contact plugs 36 protruding from the housing 11. The hole insert 38, which is made in one piece with the switch contact 39, is preferably made of bronze. The switch contact 17, the contact disk 16 and the switch contact 39 are silver-plated, at least in their immediate contact area.

List of symbols

10 pushbutton switches

11 Housing

12 Mounting lug 120 Projection

13 Touch plunger

131 Approach

132 Deepening

133 Recessed floor 135 Support

14 outer end position

15 inner end position

16 Contact disc .160 Support element

161 Side of the receiving element

162 -"- -"-

163 Edge

164 Axis

165 Axis

17 Switch contact

18 Opening location

19 Compression spring

20 End of the plunger (inside)

21 - ^H - -"- -"- (outside)

23 Floor area

24 Compression spring

25 Displacement axis

26 Housing end

27 Housing insert

28 Locking device

29 Locking opening

36 contact plugs

37 Mounting hole

38 hole insert

39 Switch contact

Claims (8)

NIEDMERS JESSENSTRASSE A ■ D-2000 HAMBURG 50 - TEL (040) 3893501 - FAX 3893502 · TELrX 2166426 pahn d DIPL-PHYS. OLE NIEDMERS DIPL-INC. HANS VV. SCHÖNING EUROPEAN PATENT ATTORNEYS Dipl.-ing. Wolfgang Priesemuth, Postkamp 13, 2210 Breitenburg-Nordoe Push button switch J>a»nn> 1. Push button switch with a housing, a projection for fastening the switch, a push button which can be moved in an essentially axial direction from a lower end position into the housing to an inner end position and out of this and in doing so opens at least one switch contact arranged inside the housing, the push button being held at a reducible distance from the location at which the switch contact, one part of which is designed as a contact disk, is opened by a first compression spring on the one hand, and on the other hand by a second compression spring arranged between the one push button end in the housing and the bottom area of the housing facing away from it, with the contact disk being enclosed between the two compression springs in its COMMERZBANK AC, BLZ 2W)4000CT,'MR.2W160011· DEUTSCHE BANK AC, BLZ 20070000, NO. 6565675 POSTGIROLAMBURd/ BLZ &iacgr;&bgr;&bgr;&Iacgr;&bgr;&Ogr;·20. ¹ NO. 13048-205 outer end position, characterized in that a support element (160) is arranged between the first compression spring (19) and the contact disk (16). 2. Push button switch according to claim 1, characterized in that the support element (160) rests essentially point-like on the contact disk (16), 3. Pushbutton switch according to one or both of claims 1 or 2, characterized in that between the second ~ Orycfcfsder (Z4) αιελει of the contact disk (?.6) a support element (160) is arranged. 4. pushbutton switch according to one or more of claims 1 to 3, characterized in that the support element (16J) is raised at least on its side (161) directed towards the contact disk (16). 5. Push button switch according to one or more of claims 1 to 4, characterized in that the support element (160) has an approximately lens-shaped cross section. ( ) 6. Pushbutton switch according to one or more of claims 1 to 5, characterized in that the support element (160) has a circumferential, plate-shaped edge (163) which, in the mounted state of the support element (160), is aligned substantially parallel to the contact disk (16). 7. Push button switch according to one or more of claims 1 to 6, characterized in that the support element (160) consists of plastic. &igr;· *· + m fm § · » m ·&ggr;·&ggr;· r » ·· · · ■■ i ³ I. 8. Push button switch according to claim 7, characterized in §5 that the plastic is polyamide. U y. Push button switch according to one or more of claims 7 I or 8, characterized in that the plastic ? is glass fibre reinforced.