GB2108324A

GB2108324A - Miniature electrical switch

Info

Publication number: GB2108324A
Application number: GB08230627A
Authority: GB
Inventors: Kaspar Egli; Franz Lang
Original assignee: SCHURTER AG H; H Schurter AG
Current assignee: SCHURTER AG H; H Schurter AG
Priority date: 1981-10-27
Filing date: 1982-10-27
Publication date: 1983-05-11
Also published as: DE8132410U1; FR2515415A1; SE8205924D0; DE3143996A1; SE8205924L

Abstract

In a push button switch, an insulating contact carrier 5 is positioned at the bottom of the switch housing 1 by means of dogs 50 inserted in recesses 14 in the housing. The contact carrier 5 holds make and/or break fixed contacts 30, integral with connections 3 which pass through funnel-like openings 13 in the base 10 of the housing 1. At least one resilient contact bridge 21 is provided in the control button 2. The contact carrier 5 also mounts a switching state indicator in the form of a LED 6 or a projection which is hidden by a diaphragm when the button 2 is in the non depressed position but which penetrates the diaphragm so as to be visible through the transparent button 2 in the depressed position of the button 2. <IMAGE>

Description

SPECIFICATION Miniature electric switches The invention relates to miniature switches, and more particularly to switches having an insulating housing containing fixed contacts electrically connected to external connection members, and a control button for moving movable contacts.

Such switches of known construction have the disadvantage that they are too big for many fields of application in front panels, printed circuit boards and the like. They are generally only suitable for one switching function.

The present invention seeks to provide a miniature switch which is reliable in operation, which can advantageously be produced economically and enables all the necessary parts to be combined in the minimum space, which parts can provide a switch suitable for closing and/or opening even multipole switching circuits.

According to the present invention there is provided a miniature switch having an insulating housing with a housing axis and which contains fixed contacts electricaily connected to external connection members, and having a control button which can be pressed into the housing, along the housing axis, against a return spring, for moving movable contacts, wherein the fixed contacts are constructed in the form of make and/or break contacts mounted in an insulated contact carrier inserted in the housing and the movable contacts are provided on at least one contact bridge secured to the control button.

As a result of the fact that the fixed contacts can be inserted in a contact carrier inserted in the housing, during assembly, make contacts and/or break contacts can be used in any desired combination.

Because of the axial stroke which the or each contact bridge executes with the control button, it is possible to determinetheswitching momentand/orthe switching function (opening or closing on pressing in the control button) by more or less long fixed contacts.

The holding of the fixed contacts in the contact carrier can be effected simply by positive locking, and the contacts constructed in the form of rubbing or sliding contacts may be close to the housing axis while the switch bridge contacts can be disposed further out. This also facilitates the construction suitable for operation which can again be restricted to the shape of the fixed contacts.

It is thus possible to make a normally-closed and/or normally-open switch by selecting between two forms of fixed contact.

The fixed contacts are each preferably integral with a connecting member. The connecting members can be taken out simply through the bottom or base of the housing at the rear, in which case funnel-like openings may be provided in the bottom of the housing in order to facilitate the assembly and to achieve as great a tightness as possible.

In order that the contact carrier may be held securely in the housing, dogs formed simply thereon may be provided which can engage in recess in the housing, in which case, with small dimensions; the mere resilience of the material is generally sufficient for secure engagement.

The miniature switch according to the invention can be provided in various ways with a switching state indicator, if a translucent and/or sufficiently transparent control button is provided, in which case the contact carrier is used as a carrier for at least part of this indication.

An electrical indication can be effected by means of a light source, particularly a light-emitting diode which is mounted on the contact carrier at the front and the connections of which are taken out towards the rear.

A mechanical switching state indicator can be realized by an indicator projection at the front on the contact carrier and a diaphragm mounted on the control button. When the control button is out, the diaphragm hides the indication projection while, with the control button pressed in, the indication projection penetrates through the diaphragm and is visible. In this case, the diaphragm can be made from a material which is sufficiently elastically deformable, which has a relatively small opening through which it is not possible to see adequately into the interior of the switch but which can be enlarged by the indicator projection so that it can pass through and become visible.

The control button can be provided with switch bridges which are engaged therein and which have a peripherally-extending web. Thus the movable contacts can be engaged bearing internally against the hollow control button in a space-saving manner and not disturb the switching state indicator discussed, for example.

It is also possible, however, to provide a contact bridge extending round the whole control button internally, with more than two contacts and also provide more than two fixed contacts, preferably with the lengths different in pairs, if multi-stage switches are desired.

Thus in addition to the simple measure of selecting the length of the fixed contacts, already described, it is possible, by simple selection of the contact bridges, to achieve a further variability in switch operation, and all the plastics parts (housing, contact carrier and control button as well as housing cover) can remain unaltered.

Here is may also be stated that it is an advantage to prevent the control button from falling out by a housing cover at the front, and this cover, made in various shapes and coloured can also take over a distinguishing function.

The contact carrier can also serve as an abutment for the return spring preferably constructed in the form of a helical spring which can be supported, for example, on the light-emitting diode inside the fixed contacts or outside these.

According to whether the switch is to be constructed with a keying operation or with detent operation, a stop spring extending predominantly axially can be provided on the contact carrier, which stop spring is capable of acting with an angled portion on a heart-shaped cam (known per se) formed externally on the control button. The notch of the heart-shaped cam is disposed at the front so thatthe angled portion engages therein after the pressing in and release of the control button and only becomes disengaged again after renewed pressing in and release.

For the easy mounting of the switch in a suitable hole in a panel-ljke part, a front external flange and swinging or rocking stop springs of a kind known per se may be provided on the housing. A rotationpreventing rib may be provided. It can also serve as a holding member if it is notched so that a holding ring can engage it.

Thus an extremely economical plurality of functions can be achieved simultaneously and/or alterna tivelywith few parts, while an extremely small construction is possible and there is operational reliability.

Preferred embodiments of the present invei .t on will now be described, by way of example on ,y, with reference to the accompanying drawings, of which: Figure 1 shows a side view of a switch according to the invention, Figure 2 shows a plan view in the direction of the arrow II in Figure 1, Figure 3 shows an enlarged view from beneath in the direction of the arrow Ill in Figure 1, Figure 4 shows an enlarged longitudinal section on the line IV-IV in Figure 2, Figure 5 shows a longitudinal section similar to Figure 4, Figure 6 shows a side view, partially in section, and enlarged in comparison with Figure 1, Figure 7 shows a longitudinal section through a control button with light-emitting diode indication, Figure 8 shows a longitudinal section through a control button with a mechanical indication, Figure 9 shows an illustration similar to Figure 8 in another switching position, Figure 10 shows a plan view of the diaphragm of Figure 8, Figure 11 shows a modification of the diaphragm arrangement in Figure 8.

Figure 12 shows a plan view of the diaphragm of Figure 11, Figure 13 shows the arrangement of two contact bridges in one control button, and Figure 14 shows the arrangement of a single contact bridge in a control button.

The switch shown has a tubular housing 1 which is disposed round an axis A and which has a base 10 at the bottom and a cover 11 at the top. A transparent control button 2 emerges through the cover 11.

In Figure 1, two stop springs 12 can be seen on the housing 1 as well as the fact that the cover 11 has an external flange 110. The switch can therefore be pushed through a hole as far as the flange 110, and the stop springs 12 can retain it in the hole. A rotation-preventing dog or rib 120 with notches 121 (Figure 1) serves the same holding purpose if it is used together with a spring known per se. The housing 1, the base 10 of the housing, the stop springs 12 and the torsion-prevention dogs 120 as well as the flange 110 can also be seen in Figure 3.

No more reference will be made to these parts with the exception of the housing 1 and its base 10.

In Figures 1 and 2 connection 3 are taken out for fixed contacts to be discussed later, as well as connections 4 for a light-emitting diode which will also be discussed later. The fact that these connections 3,4 are taken out through funnel-shaped openings 13 in the bottom can be seen from Figure 3 and can also be seen from Figures 4 and 5.

It should be pointed out in advance that the forms of embodiment in Figures 4 and 5 differ solely in that in Figure 4 break contacts 30 and in Figure 5 make contacts 300 are provided, which are made integral with their connections 3 in each case and inserted with positive locking in a contact carrier 5.

The contact carrier 5 is engaged, by means of dogs 50 formed thereon, in recesses 14 in the housing 1 immediately above the base 10.

Here, in Figures 4 and 5, the contact carrier 5 also serves to receive a light-emitting diode 6 which is mounted on the contact carrier 5 by means of its connections 4, as can also be seen from Figure 7.

Provided between the contact carrier 5 and a flange 20 the control button 2 is a return spring 7, the mode of operation of which is illustrated by Figures 4 and 5, where the control button is illustrated on the left pressed in and on the right projecting (not pressed in). Seen in the control button 2 in Figures 4 and 5 is a contact bridge 21, the duplicated arrangement of which can also be seen from Figure 13, each contact bridge 21 comprising two spring contacts 210. In this manner, the arrangement of two circuits can be provided in the simplest manner according to Figure 13, and make contacts 300 or break contacts 30 may be provided uniformly or two make contacts and two break contacts may be provided according to whether the two circuits are to be actuated jointly or alternately and in which control button position.

instead of two contact bridges 21, however, as shown in Figure 14, it is possible to provide only a single contact bridge 211 which connects all four spring contacts 210 to one another so that a multiple-contact switch is obtained if the make or break contacts 300 or or are appropriately disposed in the carrier 5. It is also possible, however, to achieve an enlargement in cross-section for a single circuit in this manner.

In Figure 6, it can be seen that a spring 8, bent in U-shape, extends with its angled portion 80 in the direction of the arrow 22, 23, round the heart-shaped cam 24 if the control button 2 is actuated in the direction of the double arrow 25. If the control button 2 is pressed into the housing 1, then the angled portion 80 is deflected according to the arrow 22 to enter the notch 27 via wedge 26 when the control button 2 is released. If the control button 2 is pressed again and released, then the angled portion 80 can spring back into its initial position along the arrow 23. The whole is called a control heart arrangement, as known peruse. Here is serves to fix the two control positions of the control button. In this switch, it is possible simply to omit the spring 8 in order to obtain a push-button switch free of end position fixing.

In Figures 4,5 and 7, a light-emitting diode 6 is installed by means of its connections 4 on the contact carrier 5 as a switching state indicator. According to Figure 7, the return spring 7 of Figures 4 and 5 can be omitted and be replaced by the return spring 70 between diode 6 and control button 2. If desired, however, both a spring 70 and a spring 7 may also be provided.

In Figures 8,9 and 10, reference is made to a mechanical switching state indicator in which a diaphragm cap 9 with a cross-slit and hole arrangeanent 90 is provided in the control button 2, which cap 9 can be pressed into the control button 2 for example. In the position of rest shown in Figure 8, the indicator projection 500, formed on the contact carrier, is hidden by the diaphragm 9, because it is not possible to see through the cross-slit-hole arrangement 90 (see Figure 10). If the control button 2 is pressed into the position shown in Figure 9, however, then the indication projection 500 penetrates through the diaphragm 9, widening it out, and becomes visible. This arrangement can be used if the diaphragm 9 consists of a suitable flexible material such as plastics.

On the other hand, if a cap 900 of relatively hard material is used, as shown in Figures 11 and 12, then a larger opening 901 may be provided therein which is closed for example by a rubber diaphragm 902 with a hole 903 which can be enlarged, in which case an indication by the indicator projection 500 can be effected as in Figure 9.

Claims

1. A miniature switch having an insulating housing with a housing axis and which contains fixed contacts electrically connected to external connection members, and having a control button which can be pressed into the housing, along the housing axis, against a return spring, for moving movable contacts, wherein the fixed contacts are constructed in the form of make and/or break contacts mounted in an insulating contact carrier inserted in the housing and the movable contacts are provided on at least one contact bridge secured to the control button.

2. A miniature switch as claimed in Claim 1, wherein all the contacts are sliding contacts, the movable contacts being disposed resiliently and the fixed contacts relatively rigidly.

3. A miniature switch as claimed in Claim 1 or 2, wherein the fixed contacts are disposed closer to the housing axis than the movable contacts.

4. A miniature switch as claimed in any preceding claim wherein the control button is non-rotatably mounted relative to the housing.

5. A miniature switch as claimed in any preceding claim wherein the connection members are integral with the fixed contacts.

6. A miniature switch as claimed in any preceding claim wherein the connection members each pass through a funnel-like opening in a base of the housing.

7. A miniature switch as claimed in any preceding claim wherein dogs on the contact carrier engage in recesses in the housing.

8. A miniature switch as claimed in any preceding claim wherein the control button is transparent and an electrical switching state indicator is provided, having a light source which is mounted on the contact carrier.

9. A miniature switch as claimed in Claim 8 wherein connection members for the light source pass through the contact carrier.

10. A miniature switch as claimed in any preceding claim wherein the control button is transparent and a mechanical switching state indicator is provided, having an indicator projection disposed on the contact carrier and a diaphragm disposed in the control button, the arrangement being such that, when the control button is out, the indicator projection is hidden by the diaphragm and, when the control button is pressed in, the indicator projection is visible, penetrating through the diaphragm.

11. A miniature switch as claimed in any preceding claim wherein said at least one contact bridge is of resilient construction and is disposed in the interior of the control button.

12. A miniature switch as claimed in Claim 11 wherein said contact bridge extends adjacent the periphery of the control button.

13. A miniature swikch as claimed in any preceding claim wherein two or more contact bridges having movable contacts are provided in the control button and more than two fixed contacts are provided in the contact carrier, fixed contacts of different extent being provided.

14. A miniature switch as claimed in any preceding claim wherein a housing cover is provided which prevents the control button frorn falling out of the housing.

15. A miniature switch as claimed in any preceding claim wherein a helical return spring for the control button is provided which is supported indirectly or directly on the contact carrier.

16. A miniature switch as claimed in Claim 15 wherein the spring is arranged in front of the fixed contacts.

17. A miniature switch as claimed in any preceding claim wherein the spring is arranged at the side of the fixed contacts.

18. A miniature switch as claimed in any preceding claim, wherein a heart-shaped cam with a notch is arranged on the outside of the control button but inside the housing to hold the control button releasably in the pressed-in position, upon which heartshaped cam or angled, radially-extending portion of a retaining spring mounted on the contact carrier acts, and when the control button is pressed in and released, the angle portion engages in the notch of the heart-shaped cam and holds the control button, while on renewed pressing in and release of the control button the angled portion becomes disengaged from the notch in the heart-shaped cam and releases the control button again.

19. A miniature switch as claimed in any preceding claim, wherein a front flange and holding means are formed externally on the housing.

20. A miniature switch as claimed in Claim 19 wherein the holding means is constituted by one or more rocking springs.

21. A miniature switch as claimed in Claim 19 wherein the holding means is constituted by a rotation-preventing rib.

22. A miniature switch as claimed in Claim 21 wherein the rotation-preventing rib is provided with a notch for the engagement of a holding ring.

23. A miniature switch substantially as herein described with reference to each of the accompanying drawings.