Claims:
1. A push button switch, comprising:
2. The push button switch of claim 1, further comprising an energy absorbent abutment carried in said housing and positioned to be engaged by said plunger as said plunger is biased axially by its said return spring,
3. The push button switch of claim 2, wherein said absorbent abutment is
4. The push button switch of claim 3, wherein said absorbent abutment is
5. The push button switch of claim 4, wherein said push button return spring presses on the one hand against said push button and on the other
6. The push button switch of claim 1, further comprising a plunger position indicator in said push button and connected with said plunger for indicating when said plunger is depressed axially against its said return
7. The push button switch of claim 6, wherein said indicator comprises illumination means and a switch for operating said illumination means, operation of said illumination means switch to selectively light and extinguish said illumination means being dependent upon the position of said plunger, and said push button being comprised so as to permit
8. The push button switch of claim 7, further comprising a light reflector in said push button; said illumination means comprising a light source associated with said reflector; said light source and said reflector being positioned so that the light therefrom is reflected out of said push button; said illumination means switch comprising contacts for said light source extending into said housing and being movable with said push button to selectively energize said light source at different positions of said
9. The push button switch of claim 8 wherein said illumination means switch further comprises cooperating contact bridges carried on said plunger and movable therewith to be engaged by said contacts of said light source.
10. The push button switch of claim 1, further comprising motion restraining means on said push button to act in opposition to said push button return spring; means on said plunger to be engaged by said restraining means, thereby to restrain said push button from full return
11. The push button switch of claim 1, wherein said push button is in the form of a pivotable key; said housing carrying a fixedly located pivot to which said push button key is pivotally connected; a lever attached to said pivotable key and engaging and pressing said plunger against its said
12. The push button switch of claim 11, wherein said push button return spring is comprised of a strip spring, which engages said key to normally bias said key to pivotally return from the position at which said key
13. The push button switch of claim 12, wherein said strip spring is connected to and is movable axially with said plunger, while said key which is pivotable by means of said strip spring is not axially movable with said plunger;
14. The push button switch of claim 1, wherein said plunger return spring and said push button return spring are connected to operate upon each other and to be biased against each other and said push button return spring is weaker than said plunger return spring.
Description:
BACKGROUND OF INVENTION
1. Field to which invention relates
The present invention relates to a switch component, more particularly for making up rows or blocks of push button switches.
2. The prior art
Mechanical push button switch units, more particularly those with mutual release of the switches, as used in the wavelength switch arrangements in radio and TV technology or in electronics generally are subject in the main to two substantial disadvantages: The mechanical switching noise, which in some circumstances may also give rise to electrical interference, or its mechanical shock action damages sensitive components such as incandescent lamps, and there is the defective alignment of the push buttons arranged close alongside one another in a greater or smaller number.
Many constructions have been proposed for damping the mechanical switching noises; the simplest construction involving the use of rubber-like abutments for the push button plungers flicked or snapped back by spring force, is usually unsuitable owing to the large tolerances resulting as regards the terminal position of the push buttons, for in the case of varying spring forces in accordance with the number of switching operations carried out on a specific push button a soft abutment is compressed to a greater or lesser extent. If, on the other hand, the spring forces are made equal, the damping action is reduced.
The mechanical switching noise increases with an increase in the mass of the switch plungers; the push button which in most cases is connected with it in a fixed manner, however, has a larger weight than the switch plunger. The mechanical separation of the two is therefore obvious and has already been proposed, although it has been adopted more for other reasons. The mechanical construction for dealing with the problem was, however, too expensive because it was necessary to arrange a push button mechanism in front of the whole switching unit so as to form a second unit and at the same time this front unit had to fulfill the task of providing optical indication of the switching on of a switch, for by means of pressure on a push button although the respective switch slide is brought into its detent-held position, the push button itself springs back into its starting position.
SUMMARY OF INVENTION
In accordance with one aspect the present invention concerns an improvement in conventional groups of push button units made up of push button switch components and involves an addition to the component housing which is supplemented by a cover plate to form a tube and usually having a U-shape, in the form of a front unit which guides the push button in a suitable manner. The push button and the switch slide possess independent return springs and abutments, and in this respect it is possible to take steps so that the push button head can be removed from the front against a certain resistance and can be placed in position again, something which is also possible in some cases in the case of the switch slide after removal of a locking means.
In accordance with a further aspect the present invention consists in a switch component, more particularly for making up rows or blocks of push button switches, characterised in that a switch plunger and a push button are carried in the same component housing but independently from each other, in that the detent means fixing the switch position act on the switch plunger, which has a return spring and can only be displaced preferentially in the thrust direction by means of the push button provided with a second return spring.
In accordance with a further development of the principle of the invention the push button or the component has at the front a mechanical switch position indicating means, which is operated by the switch slide.
In accordance with another possibility an interchangeable or replaceable fitting with an indicating lamp is incorporated in the push button and in this case in the front unit of the component housing contact lead means are provided for this lamp fitting and possibly in addition a separate lamp switch is provided which is operated by the switch slide.
In accordance with a further development of the principle of the invention in the front unit of the housing it is also possible to provide for the journalling of a push button in the form of a see-saw or piano key. A particularly simple indicating means for the switch position using a coloured slide, which moves under a window in the piano key, also forms part of the subject matter of the application. In this case a single strip spring can bring about both indication and also the return of the key or button.
In accordance with a further proposal in accordance with the invention for the mechanical damping of the return impact of the switch slide simultaneously use is made of a push button return spring which is weaker than the switch return spring, with the possible interposition of a rubber disc, which furthermore or alone serves as a damping buffer. In some circumstances it may be more practical to arrange for the push button return spring to rest against the housing independently of the switch slide.
The front unit of the component housing is preferably made in one piece in order to reduce the number of parts to be used during fitting.
Furthermore, the front unit can simultaneously incorporate interlocking means for preventing simultaneous actuation of the keys or push buttons, something which is not possible at the rear side in the case of components which have different lengths (in the direction of theh push button or key slide) in accordance with the number of switches.
Finally, the housing front unit can principally serve for an improved guidance of the push button and the push button can be loosely connected with the switch plunger so that the switched-on position becomes visible owing to an albeit minimum increase in the depth of the push button position, so that the push button only has to move a small distance on actuation.
LIST OF SEVERAL VIEWS OF DRAWINGS
The invention will now be described with reference to FIGS. 1 to 11 of the accompanying drawings.
FIG. 1 is a side view and a section through the switch unit as an illuminated push button or key in the switched-off position.
FIG. 2 shows a switch unit in accordance with FIG. 1 in the switched-on position with the push button depressed.
FIG. 3 shows a switch component in accordance with FIG. 2 in the switched-on position with the push button springing back.
FIG. 4 shows a switch component in accordance with FIG. 1 mounted in a chassis.
FIG. 5 is a plan view of two switch components, mounted alongside one another in a chassis, with lamp contacts.
FIG. 6 is a plan view of a switch component with a rubber abutment.
FIG. 7 is a side view and section through a switch unit with limited entrainment of the push button and in the switched-off position.
FIG. 8 shows a switch component in accordance with FIG. 7 in the switched-on position with the push button depressed.
FIG. 9 shows a switch component in accordance with FIG. 8 in the switched-on position with the push button springing back.
FIG. 10 shows a switch unit with a push button in the form of a piano key and with a mechanical indication of the switch position, in the switched-off position.
FIG. 11 shows a switch component in accordance with FIG. 10 in the switched-on position.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIGS. 1 to 5 show the basic principle of the novel switch component. The U-shaped housing 1 with the cover plate 2 carries the fixed contact 3 and in a conventional manner guides the switch plunger 4, which for its part has contact bridges 5. The housing 1 is extended towards the front, that is to say beyond the front plate of the chassis 20 (see especially FIGS. 4 and 5) by means of two guide lugs 1a and 1b, on which the push button 11 or key slides. The push button carries a detent 13, whose hook simultaneously serves for abutment limitation on a projection of the lug 14. The helical compression spring 8 brings about the return movement of the switch plunger 4 and for its part rests on the one hand against the bottom of the housing 1 and above against the cover plate 2, and on the other hand the spring rests against the front collar 9 of the switch plunger 4. Its centering is ensured by the housing projection 1c and the cover plate shoulder 2a.
The helical compression spring 17 serves for returning the push button 11 or key, against which it rests on the one hand and is centered by the pin 15. The opposite end of the spring 17 can lie either directly against the projections of the guide lugs 1a and 1b, or, as is shown in FIGS. 1 to 5, can rest against the switch plunger collar 9. For guiding the return spring 17 there is a pin 10 on the switch plunger. This pin corresponds to the internal diameter of the spring in accordance with FIGS. 5, 7, 8, and 9.
As an example of possible conventional detent means in the switch unit or component the U-shaped part 6 is shown which has the detent profile 7 in the push button plunger 4. In this respect the U-shaped part 6 can simultaneously serve as an interchangeable abutment for the switch plunger 4.
FIGS. 4 and 5 show an external detent means in the form of a detent slide 22 for connecting switch components which are to be subject to mutual interaction.
It is possible to dispense with the abutment locking means or latch 6 if it is a question of push button or key components which are to be subject to mutual interaction. In this case the abutment is then formed by a rubber disc or rubber coupling device 16, which on return movement of the switch plunger 4 abuts in a damped manner on the spring centering means 15 of the push button 11. In accordance with FIG. 6 a rubber disc 27 can be so formed that it cooperates with the abutments 1d and 1e, which are located directly on the guide lugs of the housing. The arrangement of the key or push button return spring 17 so that it rests against the switch plunger 4 instead of on the housing offers the advantage that the return impact of the push button in the case of mutual interaction is additionally braked by the spring 17. An essential condition for the satisfactory function of this arrangement is that the spring 17 is selected so as to be weaker than the push button switch return spring 8.
In the case of FIG. 1 the switch component is located in the switched-off position; in this position the push button 11 is held by means of the spring 17 and the hook 13 on the abutment 14. Simultaneously also the switch plunger 4 is held in its rest position by the spring 8 and the rest position is limited by the rubber disc 16, which for its part rests against the push button centering piece 15.
FIG. 2 shows the same switch component with the key or push button depressed, in the case of which the switch plunger 4 snaps into its working position. In the example the formed detent projection or profile 7 is held in the operational condition by the inwardly projecting limb of the U-shaped part 6.
The push button 11 is sprung back automatically into its initial position on release, as is shown in FIG. 3, though the switch slide remains in the operational state.
In order to make the initial and operational positions visible at the push button head, it is necessary to provide suitable mechanical indicating means or illuminating means. FIGS. 1 to 5 show the possibility of accommodation of a lamp within the push button. Preferably, a lamp holder in the form of a reflector 18 is provided, which in its tapered part accommodates the lamp 19. The lamp holder is accessible from the front after removal of the transparent cap 12.
In order to ensure that the push button is only illuminated in the switched-on position a switch of the component must be used for controlling the lamp. Current supply in accordance with FIG. 5a is via a fixed contact 23, which simultaneously carries a resilient extension 23a and makes contact with a fixed pair of contact conductors 24, leading to the lamp 19.
In order to avoid a cumbersome external connection the switch for interruption of illumination should also be provided in the front unit of the component housing. For this purpose in accordance with FIG. 5b at least one of the contact supply leads 24 projecting from the push button is connected by a resilient contact bridge 25 with the fixed contact 23. In FIG. 5b both switching operations are shown in one and the same component. In the upper half of the component the switch plunger 4 is located in the initial position and the insulating carrier 26 connected fixedly with it holds the contact bridge 25 in a position, which interrupts the contact between 23 and 24. In the lower half of the component in accordance with FIG. 5b the switch plunger 4 is in the switched-on position. In accordance with the stroke it performs it moves the contact bridge 25 via the carrier 26 into the advanced position, in the case of which the contacts 24 and 23 are connected. In the case of such an arrangement it is only necessary to ensure that the conductor or conductors 24 extending from the push button have sufficient room for displacement underneath the contact bridge and do not abut on the fixed contacts 23.
A further possibility for indicating the switched-on position, which is made visible by a semi-depressed push button but nevertheless maintains the advantages of the non-rigid connection of the push button with the switch plunger and the improved guidance of the push button, is shown in FIGS. 7, 8, and 9. Preferably, an abutment in accordance with FIG. 6 is provided consisting of the rubber disc 27 and the abutments 1e and 1d, respectively. In the sections shown only the abutments 1e mounted on the guide lug 1b are shown. The principle of the invention is closely concerned with the hook 28 on the push button 11, which in the case of the switched-on position is connected with the push button collar 9.
In FIG. 7 the switch slide 4 and the push button 11 are in the switched-off position. Between the rubber buffer 27 and the spring centering means 15 there is a small space, which in the drawing is denoted as "A." Between the hook 28 and the switch plunger collar 9 the distance is to be denoted as "b."
On depressing the push button in accordance with FIG. 8 the switch slide 4 is brought into the detent position and between the hook 28 and the switch plunger collar 9 a gap "A + B" comes into being.
On releasing the push button the arrangement as shown in FIG. 9 occurs. The hook 28 now becomes connected with the switch plunger collar 9 and between the rubber buffer 27 and the spring centering means 15 a gap of "A + B" comes into being. Therefore, the push button is in a position which lies between the detent-held switch position and the switched-off position of the push button. The measure just described ensures that on snapping back of the switch slide the impact is taken up by the rubber buffer 27 and the push button itself only moves a short distance and therefore cannot cause any heavy impact, especially as its spring loading is slight.
In FIGS. 10 and 11 the function of a switch component with a piano key and a mechanical switch position indicator is shown. The switch slide 4 can in this case as well be braked by a rubber disc 27 against fixed abutments 1d, 1e on the housing lugs 1a, 1b on return movement. For carrying or journalling the piano key it is necessary to provide a pivot point 30 lying above the housing lugs and which is created by an U-shaped adaptor 29, which is provided for by the shoulders 29 extending in an upward direction over the two housing lugs 1a, 1b until there is an engagement with the bottom 29a, and by fitting over of the shoulders 29b. The bearing means of the piano key is still more robust in an adaptor, which forms a completely closed frame and on being pushed over the housing lugs on the front snap in behind two edges, provided on the lugs, like the abutments 1d, 1e so that the frame cannot be pulled off forwards.
The piano key 31 or button has inwardly directed pins 30 on both sides and which fit into the bearing hole 30 of the adaptor 29 or the pins are arranged in the adaptor and the longitudinal holes or slots are arranged in the piano key or button. The lever 31a acting on the switch plunger 4 is attached in a fixed manner to the piano key for example by being moulded on though above the key a space 31c is provided in which the strip spring 32 can be slid as far as the foremost wall of the piano key. The spring 32, which can also be made all of a suitable plastics material, has as a first task that of returning the key. If a window 31b is provided at a suitable position in the piano key and if the strip spring 32 is attached to the switch plunger for example by being provided at this end with a fork held between the spring 8 and the switch plunger collar 9, a coloured mark 32a, which in accordance with FIG. 10 is still outside the window 31b, can be made visible in the switched-on position in accordance with FIG. 11 in the window 31b.
Naturally, for indication in accordance with this method it is also possible to use a plastics material slide, also in two colours, in combination with a strip spring 32.
Furthermore, in the piano key or in a push button it is possible to provide any other mechanical indicator, as for example one using a rotary drum or ball and adjustable hinged means, which are operated by the switch plunger .