DE2615330A1 - PUSH BUTTON SWITCH WITH MANY CONTACTS - Google Patents

Description

P ATENTAN RULES

MANITZ. FINSTERWALD & GRÄMKOW

Munich, the IB. APR. 1Ö71 P / 3 / Co-N 2080

NORTHERN TELECOM LIMITED 1600 Dorchester Boulevard West, Montreal, Quebec, Canada

Push button switch with many contacts

The invention relates to a push button switch with many Contacts, especially on a snap-action switch.

Switches according to the invention are suitable for telephone devices and are particularly advantageous for generating binary coded signals in logic circuits in telephones and other types of electrical or electronic devices used.

There is a constant demand that switches should be made more compact with minimal space requirements in the device. At the same time, the switches should be simple and reliable.

609844/0338

^FINSTERWALD DIPL. -, NG. W. GRÄMKOW ZENTRALKASSE BAYER. FOLK BANKS

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TO "μΓ" »« "'π ΪΪ« Γ ««, "?""' ^{7 STUTTGART 50 <BAD} CANNSTATT, MÖNCHEN. ACCOUNT NUMBER 7270 TEL. «089) 22 42 !!. TELEX S-29672 PATMF SEELBERGSTR. 23/25. TEL. (0711) 56 72 6! POSTAL CHECK. MÖNCHEN 7706 2-805

In a telephone or other device, the push button switch operated by users who carry out this operation with widely different features, which features can influence the signal properties resulting from the switch actuation. The special properties of the Push button, e.g. reaction, actuation force and actuation travel are therefore important.

The invention provides a push button switch with a snap action, which inevitably ensures a correct switch contact, and also a positive "feeling" of the switch activity conveyed. The push button switch has a pre "aann" te, curved spring contact plate. This contact plate undergoes the snap action after a predetermined size the force applied to the push button is reached and it snaps back after the force is removed. In particular the switch has a plurality of contacts spaced around a central point and another Contact at this middle point. The closing of the center contact is relative to the closing of the plurality around the Center contact arranged contacts delayed. This arrangement gives the option of a variety of contact closures to enter resulting binary coded signals simultaneously on many inputs of electronic logic circuits as soon as the center contact is closed.

The invention is illustrated below with reference to the drawing, for example described in more detail; in the drawing shows:

Fig. 1 shows an embodiment of the spring contact plate in Top view;

Fig. 2 is a cross-section along line 2-2 of Fig. 1 with further parts;

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FIG. 3 shows a cross section along the line 3-3 of FIG. 1, with further parts;

4a and 4a show cross sections of the spring contact plate of the figure along line 3-3, which show the contact plate in an intermediate position and in the actuated position;

5 shows a cross section through a preferred embodiment a switch containing the contact plate of Figures 1 to 4;

FIG. 6 shows the spacer disk used in FIG. 5 as a diagram; FIG.

7 shows the spacer disk of FIG. 6 in cross section;

Fig. 8 shows a printed circuit board to which a plurality of push button holders of the can be mounted in the manner shown in Figure 5, in perspective view;

FIG. 8a shows a switch position of FIG. 8 in an enlarged illustration; FIG.

Fig. 9 is a circuit diagram of a push button switch according to Fig. 5;

FIGS. 10a and 10b show the course over time of the contact closures and the signal output of a switch according to Fig. 5; and

11 shows a circuit diagram for a plurality of push-button switches according to Fig. 5

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The spring contact plate 10 shown in Figs. 1, 2 and 3 is in the form of a stamped part, for example made of stainless steel, executed. It has a flat blade part 11 which surrounds a contact section which comprises four contacts 12, 13, 1 ^ and 15. The contacts extend radially from a central portion 16 with the flat blade part 11 by radial Connecting webs 17 is connected to the outside. The contacts 12, 13, H and 15, the middle section 16 and the webs 17 are formed from the blade part 11 and given them a prestressed, arched configuration, as can be seen in FIGS. The outer ends of the contacts 12 to 15 are designed as downwardly extending rib structures - each with 12a to 15a referred to, and these rib sections form the actual contact surfaces.

When a downward compressive force, as can be seen in FIGS. 2 and 3, is exerted on the central section, the central section moves downwards, bending the webs 17. In a certain position, the middle section 17 snaps downwards, but it still has a tendency, resulting from the remaining pre-tensioning, to return to the normal position according to FIG. The webs 17 bend or kink in each case at a point 20 which rests straight radially inward on the connecting section 21 with the flat blade part 11. It can be seen that these connecting sections are initially bent upwards and the webs bend downwards just within the sections 21 as seen in Fig. 1+. In the middle part of the middle section 16, an additional contact Zl + is formed. In the preferred embodiment, this contact 21+ is formed by a depression extending downward. In FIGS. 1 to 1+ , a rigid base plate Z ^ is indicated, in the preferred embodiment a circuit carrier which carries a printed circuit 26. At 27 there is an insulating spacer washer

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• indicated, and at 31 a part of a cover appears. if the contacts 12a to 15a with the associated contact surfaces of the Printed circuit 26 make contact, there is a radial wiping actuation through the contacts on the contact surfaces. This ensures good electrical contact between the contacts 12a to 15a and the printed circuit 26.

The type of snap action and the return force of the contact plate 10 can be different, depending on the respective design. that it is bistable, stable in an undeflected position such as in Figures 2 and 3, and also stable in full distracted location. Such a plate would have no return force available to restore the undeflected position. at In such an embodiment, the circuit carrier 25 is arranged in relation to the contact plate 10 through the spacer disk 27, that the central portion 16 does not bend sufficiently downward can to reach its second stable state. The middle section will always snap back when the actuating force, for example indicated by the arrow A in FIGS ifb is indicated, is removed.

It is also possible to make the contact plate 10 so that the middle section 16 only has a stable position - the undeflected position according to FIGS. 2 and 3. The contact plate 10 of FIG. 1 to ^ f will preferably be of this type, the only being stable State is generated by the special design of the upwardly bent connecting sections 21. This is at all times ensures a positive return force on the central section, although the center portion snaps down under a compressive force applied to the center. Other training courses can also be used be provided that guarantee a positive return force at all times.

609844/0338

Another effect on the snap action and the return force is exerted by the clamping of the flat part 11 of the contact plate 10 surrounding the curved section. The clamping force indicated by the arrows B in FIGS. 4 & and 1 ± b influences the return force and can transform a bistable contact plate into a monostable contact plate if it is clamped.

As can be seen in FIG. 4a, the contacts 12, 13, 14 are made first and 15 a contact with the circuit carrier 25. The chronological order, in which these contacts are made is indeterminate because of the manufacturing tolerances. It's unlikely, that all contacts make contact at the same time, and continue to do so the order of the contacts is not necessarily the same each time the contact plate is actuated. It has to be emphasized be that Fig. 4a denotes only a through state and the contact plate does not remain in this state, but quickly moves to the position of Fig. 4ΐ> moved on ,,

The formation of a switch shown in Fig. 5 closes a contact plate according to FIGS. 1 to 4. The switch comprises the circuit carrier 25, an insulating spacer washer 27, the resilient contact plate 10 and a cover 31 · After the 6 and 7 is the spacer washer 27 made of flat material with a circular cutout 28 therein.

The cutout 28 is with the curved portion of the contact plate 10 aligned.

In the switch shown in FIG. 5, the cover 31 is provided with a recess at 32 to allow contact plate 10 To allow free space, and it has a further recess 33 and a hole 34 · In the hole 34 is a push button 35 arranged with a radially extending flange 36 at its lower end. The flange 36 moves in the axial direction

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in recess 33. At the bottom of the push button is a protruding part 37 »which rests on the central section 16 of the contact plate 10.

A compressive force applied to the upper end 38 of the push button 35 pushes the central portion 16 of the contact plate downward. After a short movement of the push button, a snap action takes place, in which the contacts 12 to 15 first come into contact with the conductors on the circuit carrier - as shown in Fig. 4-a - and then the center contact 21+ makes contact with the associated conductor produces the carrier, as shown in Fig. 1 + b . The push button maintains its following movement under the compressive force exerted by the user's finger. There is a clear "feedback" to the user, who feels the snap action and a sudden movement. When the push button is released, the middle section 16 snaps back into its normal position.

A switch of the embodiment shown in Fig. 5 is particularly useful when it is necessary to obtain simultaneous output signals from a number of circuits operated by a single switch. Thus, the switch shown in FIG. 5 supplies the coded signal for a binary coded signal circuit at all parallel outputs at the same time. The switch establishes a common contact with its contact 2.1+, which is electrically in series with the coding contacts, so that it is not necessary to generate a time-delayed switching signal in order to read in the coded data. This is inevitable for other types of binary-coded tableaus. The coding circuits are also omitted.

In logic circuits, the data is usually stored and processed in binary form. Existing input devices such as push-button panels and keypads provide the data

609844/0338

in the form of a single contact closure per push button or in the form of a matrix, such as, for example, in a 2-of-8 code. Therefore, it is bsi the existing switches necessary to provide _s logical matching circuits, the transcode a single contact closure in a binary form, or translate the 2-of-8 code into a binary form before the data through the logic circuits' / can be worked out or saved.

The inventive advantages of a switch according to FIG. 5 are

1. the guaranteed simultaneous occurrence of the coding bits Data at the outputs of a pushbutton field or a "Jählfeldes";

2. Reduced costs due to the elimination of the time-delayed Marking circles or coding circles and because of the reduction in the number of lines that connect to the keypad or the 7 / dialing field are required;

5. Simple mechanical structure with low manufacturing costs.

8 shows a circuit carrier with a circuit thereon for a plurality of binary-coded push buttons. In FIG. 8, the position of the push buttons or switches is indicated by dashed circles U.1 (a) to LI (J), with four push buttons being in a 2x5 = arrangement. Sine such Druckknopfsehalteranordnung z _"e B is suitable for use in a telephone, where the push buttons -ü.1 (a) to 41 (j) would each _5eo3 8 _s bear the numbers I ₅ 2, _{e <9 S} O 'V If one pushes or depresses one of the push buttons, a binary code is generated. The contact sections of the printed circuit boards below the push buttons are connected to the output connections k2-

609844/03 j8

43 s 44 and 45s 46 connected. The outputs 44 and 4-5 are outside of the circuit carrier 25 connected to one another. Another Connection 47 for a mark signal is also provided. The output 47 is connected to a contact 48 which, vjenn the snap fasteners and the other parts are already assigned, in contact with the spring plate 10. All contacts for all button positions It is advantageous to ground vj on a large contact plate educated. The contact 48 can consist of a conductive rubber part, consist of one: conductive epoxy resin or some other device. Sin contact 49 in the tit of each snap position - The one with the center contact 24 of each individual switch in contact koar.it - is connected to a; :: further output 50 en.

The binary code relating to each individual button and output link is shown in Table I.

Tabel I. 46 44 43 42 1 0 45 0 1 1 0 0 1 0 1 4Ua) 0 0 1 1 1 41 (b) 0 0 0 0 1 4Uc) 0 1 0 1 1 4Ud) 0 1 1 0 1 4Ue) 0 1 1 1 1 4Uf) 1 1 0 0 1 4Ug) 1 0 0 1 1 41 Gi) 1 0 1 0 4Ui) 0 4Kj)

i7 (Ilmarking)

609844/0338

BAD ORiGiNAL

Thus pushing or depressing a button labeled with the number - button JfIe in Fig. 8 and panel I - yields the code 0101.

Other arrangements of the buttons can be provided and the arrangement of the buttons and the code used can be changed. For example, a 3 x if arrangement, as in a normal Telephone is commonly used, or an arrangement as used in calculators or other types of buckets will. A binary code which differs from that given in Table I can also be used.

For each button or switch area there are four main contact surfaces 51 »52, 53» 5A- which are arranged in such a way that they interact with the contacts 12, 13, H and 15 of a contact plate shown in FIGS. Although only one such contact surface needs to be connected to generate a particular binary number, it is preferred that all four contact surfaces are provided under each push button or button so that the movement of each individual contact finger remains the same. The unused contact areas at all of the switches are interconnected so that none of them are left indefinitely, which would create the risk of becoming electrically charged, causing incorrect coding and possible destruction of high impedance circuits. As stated above, the center contact surfaces 55 are shown connected to the output 50 with a connection 50 shown in dashed lines. These connections can advantageously be made on the underside of the circuit carriers, for example by plating through holes. The contact surfaces 51 to ^ are shown with details for a switch point in Fig. 8a.

609844/0338

Fig. 9 shows in connection with FIGS. 5 and 8 schematically Actuation of the various contacts, Fig. 10a and 10b showing the improvement of the outgoing signals. As in Fig. shown, an input signal via the output 50 to the Contact point 55 of the circuit carrier with the center contact 24 Make contact, given.

It is shown that the contacts 12 are to 15 respectively connected to the contact surfaces 51 to 54 in connection with the contacts, it is 12 to 15 parallel to each other are _e The contact 24 is connected in series with the contacts 12 to 15 and raie previously described set up so that the contacts 12 to 15 are closed before the center contact 24. The output from the contact areas 51 to 54? 51a to 54a are designated for convenience, may or may not be present, the code distinguishing the buttons in an arrangement being created by an appropriate selection of the possible combinations of the contacts 12a to 15a. Thus, in FIG. ₃ 9, no output is indicated for the contact surface 53. In the same way, other connections and associated outputs can be omitted. The spring contact plate 10 also makes contact with a contact pin on the circuit carrier, as previously described, in order to prevent false signals from being emitted as a result of static charges or arcing if the contact Zk is interrupted when the pushbutton is released. This is shown schematically in FIG. 9 by the connection to. Earth 56 is displayed via resistor 57.

Because of manufacturing tolerances, it is impossible to align the contact fingers 12-15 so that they all make contact at the same time. Therefore, an input that can be assumed to be input at 58, for example, will not appear at the outputs 51a to 54a at the same time, since the ^l? Closing times ^i! of the contacts differ. This is shown schematically

60984 4/033

" ¹² " 261533Q

in Fig. 10a, which shows the output signals as they appear at the output terminals 51a, 52a, 53a and 5 ^ -a, as a function of time when the input signal at the input terminal of the spring contact plate - in Fig. 8 at 47 - is input and is therefore fed directly to contacts 12, 13, 14 and 15. As shown in Fig. 10a, there is a time spread close to At. The point in time of the mechanical contact connection is indicated by the short vertical lines 59. FIG. 10 also shows the code signal according to the arrangement of FIG. 9, in which the signals appear as outputs 51a, 53a, 54a and there is no signal at 52a because this output does not exist. The output of the binary code is indicated in FIG. 10 at the outputs 51a to 54a. FIG. 10b illustrates the improvement in the time relationship of the output signals at output terminals 51a to 54a when the input is applied to input terminal 5o in FIG. 8 and thus delayed until contact 54 is made, which occurs at time t in FIG. 10b. Figures 10a and 10b illustrate what might be seen on an ocilloscope, with each of the four tracks representing a different one of the outputs 51, 52, 53 and 5k .

With the creation of the central contact 24, which closes after all the other contacts are closed, the outputs at the output terminals 51a appear to 54 ^a simultaneously with the closing of the contact 24 'as shown in Fig. 10b ist.Zusätzlich the output provides 58 corresponding to contact 47 for an output when any of the buttons is depressed and thus provides a marking function useful in some applications. For example, output 58 provides a zero output for all actuations.

The number of contacts per push button need not necessarily be four, but can be changed, however, this is The number of contacts that can be accommodated under any push button is limited. For telephone and other purposes

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261S330

four contacts are usually sufficient, but in other applications the number of contacts limits the number of bits and the number of buttons per arrangement.

However, the arrangements can be multiplied by using switches as described above, for example with relation to FIG. 3, and using simple gates or similar devices. 11 shows such an arrangement for a total of 61+ keys with 1+ bits per 16 keys.

Fig. 11 shows a binary arrangement with 6k keys. A push button is indicated at 60, but it is clear that this is one of a module of 16 push buttons. In the same way, 61, 62 and 63 each show individual pushbuttons, which designate one of three other similar pushbutton modules. For the sake of clarity, only one pushbutton of each module is shown.

If one looks first at the push button 60, it has four contact surfaces, which are indicated schematically by the reference numerals 60a, 60b, 60c and 60d. Contacts 60e, 60f, 60g and 60h are also indicated, these contacts corresponding to contacts 12, 1314 and 15, respectively, in FIGS. 1 to 5. The central contact, which is denoted by 64 and corresponds to the contact 2.1+ in FIGS. 1 to 5, makes contact with a central contact surface 65 which corresponds to 50 in FIG. 8.

In the same way, there are contact surfaces for the push buttons 61, 62 and 63 at 61a, 61b, 61c and 61d; 62a, 62b, 62c and 62d; and 63a, 63b, 63c and 63d respectively with the contacts at 61e, 61f, 61g and 61h; 62e, 62f, 62g and 62h; and 63e, 63f, 63g and 63h, respectively. The center contacts on the spring contact plates

609844/0338

are each designated with 66, 67 or 68 and the entire contact areas with 69, 70 or *] \ .

If one goes back to the first push-button module, which is denoted by 60, the contact surfaces 60a, 60b, 60c and 60d are individually connected to the output rails 75, 76, 77 and 78 in accordance with the desired code. Thus, in Fig. 11 connections from all contact surfaces 60a to d, 61a to d, 62a to d and 63a to d are shown. It is not necessary, however, that all of these connections exist. In the same way is to be considered for the push-button module at the point indicated by 60 that only one push-button or switch of those located in the push-button module is indicated and that the connection between the contact surfaces and the busbars for each of the 16 push-buttons or switches can be different. The same applies to each of the push-button modules with 16 buttons connected to the push-buttons indicated at 61, 62 and. Two additional output bus bars are provided at 79 and 80. To obtain an I ¹ notch zero output when pushbutton zero is pressed, an output labeled 81 and labeled "mark" is provided.

To make arrangements for the additional 16 snap button assemblies to meet at the snap fastener parts 61, 62 and 63, the Spring contact plates at 85 and 88 connected to the busbar 79 via diodes 86 and 90, respectively, and at 87 and 88 with of bus bar 80 via diodes 89 and 90a. This ensures that when any push button in the module 61 is off 16 push buttons is pressed, a logical 1 on the busbar 79 appears when a pushbutton in module 62 is pressed

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a logical 1 on busbar 80 and any push button in module 63 a logical 1 on the busbars 79 and 80 is caused.

An input bus is indicated at 91, and the contact plates are also connected to an earth rail 92 via resistors 93, to prevent static electricity.

Thus, the arrangement can be as desired by providing the connections 85, 87 and 88, through further busbars 79 and 80 and extended by diodes or gates 86, 89, 90 and 90a, although the number of contacts available for coding purposes has been shown to be limited to four under each push button, which is considered the optimum for practical purposes. If you expand on 128 push buttons, 12 diodes or gates would be required. Under such conditions, it might be more practical to use three OR gates with four inputs each instead use.

The circuit carrier that is used for coding the contacts and The connections to the busbars can be made using standard printed circuit design techniques designed and manufactured in accordance with generally accepted printed circuit processes.

The invention thus relates to a push-button switch which attaches a spring contact plate and a circuit carrier one above the other contains. The spring contact plate has one or more Switching points, each of which is surrounded by a flat part of the blade, includes prestressed, arched section. The arched sections contain a central part and radial webs that connect the middle part to the flat part of the blade. Each web has an upwardly bent portion at its junction

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with the flat part of the blade. Resilient contacts extend radially from the central portion with each contact between one. A pair of webs is located, and on the central part there is provided a central joint. The arched section is pre-stressed so that it assumes a stable position above a plane that is separated from the plane by the flat leaf. A push button acts on the central portion and a compressive force exerted on the push button causes the central portion to snap through the vial of the flat blade portion. The resilient contacts make contact with contact surfaces on the circuit carrier, and then the center contact closes a contact with a further contact surface on the circuit carrier. If the push button is released, the curved section can snap back into the stable position.

- patent claims -

609844/0338

Claims (4)

- ¹⁷ - 261533Q Claims Push-button switch, characterized by a spring contact plate (10) which has a pretensioned, arched Section and a flat blade part (11) surrounding this curved section, the curved section having a central part (16) and radial webs (17), which connect the central part (16) to the flat blade part (11), and is pretensioned so, that it has a coincident above one with the flat blade part (11) Has a stable position located flat, each of the radial webs (17) having an upwardly bent section (21) at its connection with the flat blade part (11), wherein a plurality of resilient contacts (12, 13 »14» 15) extend radially away from the central part (16), and each contact (12, 13 »14» 15) extend between a pair of the radial webs (17) extends, and on the central part (16) there is a central contact (24), further characterized by a Circuit carrier (25) which is arranged below the spring contact plate (10) and separated from it and below the resilient Contacts (12, 13, I4, 15) and the central contact (24) contact surfaces (26) includes; and by a push button mounted above the central part (16) for applying a related on the flat blade part (11) downward force the arched section; wherein pressure on the push button (35) presses the central part (16) from the stable position downwards and the radial webs (17) at the curved sections (21), wherein the central part (16) through the with the flat blade part (11) coinciding plane snaps, the resilient contacts (12, 13 »14, 15) in contact with the associated contact surfaces (26) come, and the center contact (24) contacts the associated contact surface (26) after the resilient contacts (12, 13, I4, I5) 609844/03 3 8 have made, and that after releasing the push button (35) the curved section returns to the stable position. 2. Push button switch according to claim 1, characterized in that the spring contact plate (10) has a plurality of switching points includes, the circuit carrier (25) has contact surfaces (26) at each of the switching points, and a predetermined arrangement of contacts is present at the contact surfaces; and that a variety of snaps (35), a push button at each switching point, is available. 3. Push button switch according to claim 2, characterized in that a cover (31) extends over the spring contact plate (11), that a plurality of openings (3 * f) in the cover (31), one opening for each push button, is present and that there are interacting formations (33j 36) on the cover (31) and each of the push buttons (35) to hold the push buttons (35) in place. 4. Push button switch according to claim 2 or 3 for a binary coded Signal system, characterized in that each contact surface (26) has a predetermined contact arrangement has to generate a predetermined binary code after pressing the associated push button (35). 609844/0338 Blank page