DE2365083A1 - KEY SWITCH PANEL - Google Patents

Description

The invention relates generally to a keypad of the type used in an electronic computer will.

Keypad switches have already been proposed where a conductive dome-shaped element with a snap action is used as the switch element. See such switches are, for example, in U.S. Patents 3,643,041 and 3 684 842, in German patents 486 212 and 1 806 241 and in the IBM Technical Disclosure Bulletin

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No. 12, Vol. 7, May, 1965, page .1168 entitled "Snap-Action Membrane Switch Keyboard". Another key switch panel of the same general type made by Texas Instrument Incorporated uses a circuit board with conductors on one face with brackets extending through the board from the other face to one face and with selected conductors on it are soldered, and snap action domes that cooperate with the parts of the brackets on the other side of the plate to perform the switching function. Another type of keypad switch manufactured by Colorado Instruments Corp. has a circuit board with conductors on both faces, which board is provided with plated openings extending therethrough and connected to certain conductors ₉ and snap-action studs that cooperate with plated openings to perform the switching function.

The above-described types of keypad switches known to the applicant employ any one of them Combination of double-sided circuit boards, soldered connections and / or a conductive earth plate in addition to a circuit board, which features complicate the structure and a considerable increase in cost to lead. It is therefore desirable to have a key switch panel of the general type described above which utilizes a single sided circuit board and where no soldered connections or an additional conductive earth plate are required.

The invention is directed in a broader sense to a key switch panel that one from Eand from a rest position in a switch actuated position actuatable pushbutton also has a conductive switch member having a

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elastic element which can be actuated by the push button from a normal to a bent position is. The key switch panel has an insulating plate opposite faces, one of which with. first, and second conductors is provided, the first conductor one first switch connection part and the second conductor has a second switch connection part. The switch is linen faces the one surface of the circuit board and the conductors and has a first contact surface, the is at a distance from the central surface of the element, which first contact surface is against the first connection part is present. The central surface of the element forms a second contact surface in register with the second Connection part and rests against this when the element is in its flexed position, whereby the first and second connector parts and the "respective ones." Conductors are electrically connected to each other.

The object of the invention is therefore to provide an improved key switch field.

It is also an object of the invention to provide a key switch panel of the type in which a conductive snap action dome is used as a switch element.

Another object of the invention is to create an improved buttons s chalterfe.ld of the type in which a snap action dome used as a switch element with a single-sided circuit board and avoiding soldered connections and / or conductive earth plates are.

The aforementioned and other features and objects of the invention and the manner in which this

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will be sufficient, result from the following in more detail Description in conjunction with the accompanying drawings of an embodiment of the invention. Show it:

Fig. 1 is a schematic representation of a simplified Dual line keypad switch matrix;

Fig. 2 is a plan view showing an insulating plate with XY conductors and switch terminals in an inventive Fig. 3 shows arrangement for obtaining the keypad switch matrix of Fig. 1;

Fig. 3 is a view in section along the line 2-2 in Fig. 2, which is the basic switching element used in the invention shows;

Fig. 4 is a plan view, partially broken away, which shows the preferred embodiment of the invention Key switch panel shows;

Figure 5 is a sectional view taken along line 5-5 in Figure 4;

6 shows, on an enlarged scale, a partial view which Figure 3 shows a portion of the circuit board used in the preferred embodiment;

Fig. 7 is a view in section along the line 7-7 in Fig. 6;

Fig. 8 is a plan view of the snap action clutch element; that in the preferred embodiment is used;

Fig. 9 is a partial view showing the configuration of one of the Shows openings in the switch element holding member;

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Fig. 10 is a partial exploded perspective view, which further Details of the Preferred Embodiment the invention shows;

Fig. 11 is a partial sectional view showing another embodiment of the invention;

Fig. 12 is a plan view of the in the embodiment according to 11 switch element used;

Figure 13 is a plan view of a modified form of the switch element shown in Figures 11 and 12; and

Figure 14 is a top plan view of a modified form of the switch element shown in Figures 4-10.

Essentially, a key switch panel for an electronic device, for example a computer, can be viewed as an XY matrix of conductors, the X conductors being isolated from the Y conductors, a particular function being characterized by the fact that an electrical Contact is established between a selected X-conductor and a selected Y-conductor. The simplified double-line switching matrix shown in FIG. 1 has X ^ and X ₂ conductors isolated from Y. and Y ₂ conductors, the switching functions being performed by switches S ₁ -S ₁ . It should be mentioned here that the number of X and Y conductors in the keypad matrix can be any integer that is equal to or greater than 1, and that the number of possible switching functions is equal to the product of the number of X conductors and the Number of Y-conductors is. Momentary contact push button switches are commonly used to make the required contact

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used between the X and Y lines.

The aforementioned key switch panel from Texas Instruments uses a single sided circuit board with the required insulation at the X-Y crossing points, the formed by conductive U-shaped brackets that extend through the plate and the legs of which are soldered to the conductors on one side, while their web parts rest against the other side of the plate. The aforementioned Colorado Instruments key switch panel uses a double sided circuit board with the X conductors on one side and the Y conductors on the other Side, where plated through holes are used to have X-contacts on the same side of the plate as to get the Y contacts. In the case of the two switch panels mentioned, the circuit board serves as insulation between the X and Y conductors using brackets or plated through holes to separate the Bring the X and Y contact points to the switching side of the plate.

In the case of the key switch panel according to the invention, the Thickness of the circuit board is not used as insulation between the X and Y conductors, and no conductors are provided, which extend through the plate make electrical contact from side to side form. As shown in FIGS. 2 and 3, according to the invention is one Insulating plate 1 provided with X and Y conductors, which are attached to the switch side, the switches according to are arranged in a certain pattern, and connecting parts 2, 3 have, which for cooperation with the respective Switching element S are intended to establish contact between selected X and Y conductors without other conductors to touch.

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The switching elements S are made of a conductive elastic material, and each have edges or Circumferential contact surfaces 5 on one or several Y-connector parts 2 rest j the switching element has a normal position, as shown in full lines in Fig. 3, in which its central Contact surface at a distance from a respective X connection part 3 is located. Furthermore, the switching element 4 is located at a distance from other X and / or Y conductors, as shown. When a downward force is exerted on the switching element 4, as indicated by the arrow 7, and how it is exercised when a pushbutton is manually operated, the switching element 4 in FIG bent a position, as indicated by a dash-dotted line 4a, in which its central Contact surface 6 contact with a respective X-connection part 3, whereby the respective X and Y conductors are electrically connected. As can be seen, this has Switching element 4 in its bent position has no contact with the other conductors, for example with the ladders underneath Y ... When the down Directed force 7 is canceled, the switching element 4 returns elastically to its normal position, whereby the electrical connection between the respective X and Y-conductors is interrupted.

In Fig. 2, the arrangement of the switching elements S with respect to the X and Y connection parts is shown with dashed lines. For example, the switching element S can be of the type shown in FIG. 13, the switching element S 1 can be of the type shown in FIGS. 4-10, the switching element S ₃ of the type shown in FIG ₁₊ can be of the type shown in Figs. 11 and 12, it being noted that all switching

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elements for a given key switch field in the generally have the same shape.

The preferred embodiment shown in Fig. H-IO the key switch panel according to the invention, which is generally designated 10, has a one-sided Circuit board 12, snap action cup retainer 14, an insulating switching element holding plate 16, a insulating cover plate 18, a cover 20 and push buttons 22. The switching elements 14 and the insulating plates 16, ■ 18 are sandwiched between the circuit board 12 and the cover 20 and the key switch panel is through Rivets 24 held together. The illustrated embodiment of the key switch panel 10 is for use in determined by an electronic computer.

Although the key switch panel 10 has a number of switch sub-units 2 8 up, ν, οη each of which has a push button 22, a snap action dome switch element 14 and associated switch terminals and conductors on the top 2 6 of the circuit board 12, the switch subassemblies are similar and functionally identical so that the A description of such a sub-unit 28 is sufficient.

The circuit board 12 shown in Fig. 6 and 7 is formed by a plate made of rigid plastic, which carries a copper-plated surface 26, the conductors and connections on the surface 26 by a per se known photogravure technique can be formed. Each switch subunit 28 has three switch terminals 30 on the Surface 26 in the arrangement of an equilateral triangle and a central switch terminal 32 on surface 26, which is arranged in the middle of the triangle formed by the outer connections 30. With the special in

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Switch subunit 28-1 shown in FIG. 6 are two of the outer connections 30-1 and 30-2 through a conductor 34 connected to the top 26 of the plate 12 and to the terminal 30-2 is another conductor 36 on the top 26 connected. Due to the geometry of the conductor arrangement on the top 26 of the plate 12 is with the Terminal 30-3 of switch subunit 28-1 does not have a conductor connected, but other of the switch subunits 28 all three switch connections 30 can be connected by a conductor. In the particular circuit board arrangement shown is the outer connection 30-3 'of the switch subunit 28-2 also, with the conductor 34 tied together.

The central terminal 32 of the switch subassembly 28-1 is connected by a conductor 38 on the top 26 to an external terminal 40. The other ladder on the Top 2 6 of the plate 12, like the conductors 42, 44 and 46, which through the outer "terminals 30 of the switch subunit 28-1 bounded triangle, connect further outer connections with the connections of further ones Switch sub-units.

The conductor 48 on top 26 of the plate 12 surrounds partially the central terminal 32 of the switch subunit 28-1 and is located by this and the conductor. 38 in distance. In the particular circuit board shown is the conductor 48 is connected to the conductor 5 0 on the upper side 26 of the plate 12, the outer terminal 5 2 with one terminal of another switch subunit 28 connects. In other switch sub-units, for example at subassembly 28-2, conductor 48 'completely surrounds the central terminal 32 'and is .er with the conductor 38' connected on the upper side 26, which connects the central connection 32 'to the outer connection 54.

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As shown in FIG. 7 shows _s the top 26 of the circuitry 'plate 12 and the guide on this -from a thin layer 5 of insulating material 6 covered with the terminals 30 have been covered during application of the insulating layer 3 2 5 6 so that these connections do not have an insulating layer. The terminals 30, 32 are provided with a plating 58 of gold or nickel.

Although the conductors, connections _s the insulating layer 5 6 and

the plating 58 in Figs. 5 and 7 to be substantial

Thickness is shown, these elements are of course very thin in reality.

Reference is now also made to FIG. 8. In the preferred embodiment, the snap-effect tip switching learning has nt 14 is substantially the shape of a triangle 'with crests 60 which are curved arcuately about a Mittelpunkt'62 around ₉ and have flat sides between them 62nd The switching element 11 can also be referred to as being essentially circular, parts of which circle have been removed to form tendons 6 2 between the arcuate parts 60. At the tips 60, projections or E are formed in depressions 64- downwards and a central projection or a central recess 66 is formed in the interior of the dome.

The snap action dome switch element 14 of the switch subassembly 2 8-1 is positioned over top 26 of plate 12, conductors 34-48 and central terminal 32, and facing, with the outer .Vorsprünge 64 abut against the outer connections 30, whereby the circumference of the Switching element 14 is held above the conductors and connections, as can best be seen from FIG. Of the central projection 66 is located in overlap and in

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Distance from the central terminal 32 in the normal position of the snap action coupling switch element 14, as shown in solid lines in FIG. Exercising a downward force on the switching element 14, as indicated by an arrow 68, has the consequence that the switching element 14 from its normal Position bent into a non-over-center position is, as shown with dash-dotted lines 70, in which the central protrusion 66 against the central contact 32 is applied, whereby the central contact 32 is electrically connected to the outer contacts 30 to the desired complete electrical circuit.

The conductor 48 partially surrounds the central terminal 32 (or the conductor 48 'completely surrounds the central terminal 32 ') and its insulating coating 56 and forms a cushion which prevents damage to the central Projection 66 on the snap action cup holder learns 14, d · .h. the exertion of excessive force in the direction on the switching element 14 has the consequence that the surface surrounding the projection 66 is in contact with the conductor 48 covering insulation moved, causing further downward movement of the dome and damaging the protrusion 66 is avoided.

The retaining plate 16, which covers the insulating layer 5 6 on the top 2 6 of the circuit _{board 12, 4} is formed from a plate of a relatively thin flexible insulating material, and has openings 72 which serve to receive and hold the snap-action dome retaining elements 14, which openings are essentially adapted to the shape of the switching elements 14, but have cutouts 74 which are aligned with the projections 64 which expose parts of the outer connections 30 (FIG. 9).

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The cover plate 18 is made of an uninterrupted plate made of a relatively thin flexible insulating material shaped and covers the holding plate 16 and the switching elements 14. The lid 20 covers the plate and is provided with openings 76 for receiving the pushbuttons. Each push button 22 is on its underside formed with an X-shaped projection 78, which is connected to the central projection 66 of the switching element 14 in ■ Overlap is. The projection 78 lies against the Surface of the cover plate 18 above the central protrusion, but does not normally exert any force on it with the exception of the small force that is its own weight is to be attributed and which is insufficient to deflect the switching element 14 into its actuated position 70. The exercise of a finger pressure by hand on a special push button 22 has the consequence that a force in the sighting 68 exerted through the cover plate 18 on the respective snap action clutch element 14 is, whereby the switching element in its non-over-center or. flexed position 70 is operated to the desired. Perform switching function. When you stop the finger pressure on the push button 2 2 returns the respective switching element 14 elastically to its normal position, whereby the previously formed circuit is interrupted and the respective pushbutton 2 2 in its normal rest position is returned.

As for Fig. 11, are provided in which the same elements having the same reference numbers, and similar elements have the same reference numerals with a prime, each lower switch unit 28 ^for a central connector on the top side 26 of the circuit board 12 and a single external port 30 'is also on the top, the connection 3 2 and the out of its connection 30 '.

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are connected by conductors (not shown) at the top 26 to external connections (also not shown). A plate 82 made of a relatively thin insulating material covers the upper side 26 and the conductors 84 thereon and has openings 86, 88 through which the connections 30 ¹ , 32 are exposed.

In this embodiment, the snap action clutch mechanism learn nt IM- 'an essentially rectangular shape, wherein the flat portion 90 with the circumference of the dome portion 92 is made in one piece. The projection 64 'is from the flat part 90 is formed, and the protrusion 66 is off the central surface of the dome 92 formed.

The flat part 90 of the switching element 14 'is on the Upper side of the insulating plate 82 supported so that "the projection 64 'extends through the opening 8 6 and against the connection 30 'rests, the projection 66 being in overlap with the opening 8 8 and the connection 32. The insulating holding element 16 covers the insulating plate and is provided with openings 72 'for receiving and Serve holder of the switching element 14 'and the rectangular Shape of the switching elements 14 'are adapted.

The cover plate 18 covers the holding element 16 and the cover 20 (not shown in FIG. 11) in turn covers the cover plate 18 and has openings 7 6 for receiving and holding the pushbuttons 2 2. The hold effect the embodiment of FIGS. 11 and 12 is practically that 4 to 10 identical, i.e. the exertion of a finger pressure on the pushbutton 22 has the consequence that the X-shaped projection 78 exerts a downward force on the central surface of the respective dome 92 via the Cover plate 18 is applied, whereby the dome 92 from their normal position shown in Fig. 11 in their

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The over-center or bent position is actuated, in which the projection 6 6 extends through the opening 88 in the insulating plate 8 2, and against the center contact 32 is applied to thereby the switching function achieve.

In Fig. 13, in which like elements are given the same reference numerals and like elements denote Carrying the same reference numerals with a dash is a modification of the switching element according to FIG. 11 and 12 with an additional contact projection 65 shown in flat part 90 on the opposite of the projection 64 ' Side of the dome part 92 is formed.

In Fig. 14, in which like elements are also provided with the same reference numerals and similar elements with the same reference numerals and a prime, is a modification of that shown in Fig. 4-10 (particularly in Fig. 8) Switching element 14 is shown in which the dome retaining element 14 "has a substantially rectangular shape with curved corners 60" which are connected by straight sides 6 2 ⁿ _s in which corners 60 "contact projections or recesses 64 are formed. As can be seen, this can Switching element 14 "are formed by cutting straight edges 62" from a circular snap action dome.

Although the snap-effect tip switching elements in the preferred embodiment shown are the _s audible and tactile feedback is, of course, not required by the "oil can" effect of a dome for the switch function and other kinds may be used by switching elements. The main requirement of the switching element is that it can be pressed in order to close a circuit between the X and Y lines, has the necessary elasticity to return to its initial position when the actuating force is stopped, as well as a

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Shape that establishes the required electrical connection between a selected XY conductor pair, if
it is pressed without touching other conductors, which connect contact points for further switches on the same board with each other. Although an insulating coating or an insulating layer has been described which covers the circuit arrangement with the exception of 'the connection parts, such an insulating coating or a Such an insulating layer is not a requirement, since the correct arrangement of the conduction paths and the correct deflection properties of the
Switching element an insulating coating can be made superfluous.

The design of the switching element shown in Fig. 8 and I ¹ + is preferred, since the use of three points or corners with contact projections or recesses result in the support points for the dome around its circumference, ensuring the intermediate flat sides that are formed by the dome Are cut off, a proper alignment of the contact projections by the dome retaining plate 16..

Although a printed circuit board has been shown and described, the XY conductors on one face can be a
Isolation plate can be attached in a manner other than a photo-engraving process.

The invention is of course not limited to the forms shown and described, but can be used within undergo various changes to its framework. '

Patent claims:

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Claims (22)

Sponsorship claims e Key switch panel with a push button selected from. Hand. From a rest position to a switch actuation position can be actuated, and a conductive switching element which is formed by an elastic element is and actuated by the push button from a normal position to a flexed position and resiliently returns to its normal position when the pushbutton is applied strength ceases, characterized by an insulating plate with opposite faces, only one of which is a first and carries a second elongate conductor, the first conductor being provided with a first switch connector and the second conductor has a second switch connection part, which conductors and connection parts are are located essentially in the same plane, the mentioned switching element of the mentioned one surface and is arranged facing the conductors, the switching element is provided with a first and a second contact surface which are located at a distance from each other, which first contact surface rests on the first connection part, the second contact surface is in overlap with the second connection part and rests against it, if the switching element is in its bent position, in which it the first and the second connecting part connects with each other, and means by which the pushbutton, the switching element and the circuit - 16 - 4Q9829 / 0972 M 9 768 plate are held in working position to each other. 2. Key switch panel according to claim 1, characterized in that said switching element is a Snap action dome and the second contact surface is in the center of the dome. 3. key switch panel according to claim 2, characterized in that the first contact surface by a projection is formed on the mentioned switching element, the circumference of the dome of the mentioned one surface the circuit board and conductors at a distance. 4-. Key switch panel according to Claim 3, characterized in that that the mentioned projection is formed on the dome adjacent to the circumference thereof. 5. key switch panel according to claim H, characterized in that that the switching element has a flat part which connects to the circumference of the dome, and the projection is formed out of the flat part. ' , 6. Key switch panel according to Claim 2, characterized in that that the second contact surface is formed by a projection in the interior of the dome. 7. key switch panel according to claim 1, characterized in that at least a portion of the second 4098 29/0 97 2 - 17 - M 9768 j Conductor under the mentioned switching element of one extends from this remote place on the aforementioned one surface. 8. key switch panel according to claim 1, characterized by a layer of insulating material which covers the mentioned conductors with the exception of the connection parts ". Key switch box _s according to claim 8 characterized in that the said switching element is a snap-action dome, the second contact surface is located in the center of the dome, the above-mentioned one surface of the circuit board a third Leiter'trägt, which at least partially surrounds the second terminal part of this one has a narrow spacing and is essentially in one plane with this, the surface of the dome surrounding the second contact surface rests against the insulation which covers the third conductor when the dome continues after the second contact surface has been in contact with the second connection part is deflected to protect the second contact surface. 10. Key switch panel according to claim 2, characterized by a third and a fourth switch connection the mentioned one face of the circuit board, which third and fourth terminals and the first terminal part are arranged in the shape of a triangle so that the second connection part is inside the same, the first contact surface by a first projection - 18 409829/0972 M 9768- is formed, which is adjacent to the circumference of the dome is formed, at which tip a second and a third protrusion is formed adjacent its circumference is which projections abut on the third or on the fourth switch terminal, and which projections the Keep the circumference of the dome at a distance from the mentioned one surface of the circuit board and the conductors, which second contact surface a fourth from the inside the dome is formed projection. 11. Key switch panel according to claim 10, characterized in that that the switching element is essentially the shape of a triangle has, which is provided with arc-shaped tips and is equiaxed to the center of the dome, the first, the second and third protrusions are formed from the aforementioned tips. 12. Key switch panel according to claim 11, characterized in that that the holding means through a layer of insulating material be formed, which covers the conductors with the exception of the terminal parts and terminals, a first Plate made of insulating material covers this layer, and an opening for receiving the switching element "adapted to hold the same, a second plate of insulating material, the first plate and the Switching element covers and a plate part covers the second plate and an opening for receiving the pushbutton which acts on the dome through the second plate. - 19 - 409829 / Q972 M 9768 ' 13. Key switch panel according to claim 11, characterized in that a portion of at least the second The conductor extends under the dome from a point on the mentioned surface facing away from it, the mentioned one surface of the circuit board carries a third conductor, which is at least partially the second connector surrounds part, is located from this at a distance and essentially in the same Level like this lies, which conductor with the exception of the connection parts a layer of insulating material wear, the surface of the dome which surrounds the fourth projection, rests against the insulation that the third conductor covered when the dome after the abutment of the second contact surface on the second connection part is further deflected to thereby protect the fourth protrusion. Key switch panel according to Claim 13, characterized in that the third conductor is the second connection part completely surrounds and is connected to the second conductor. 15. Key switch panel according to claim 13, characterized in that the third conductor is the second connection part partially surrounds and with a fourth conductor on the mentioned surface of the circuit board, which-under the dome extends, is connected. 16. Key switch panel according to claim 13, characterized in that the first conductor at least with the second - 20 -. 409829/0972 M 9768 J / Connection is connected. 17. Key switch panel according to claim 13, characterized in that that the circuit board carries a fourth conductor which extends below the dome. 18. Ta, stenschalterfeld according to claim 2, characterized through a third, a fourth and a fifth switch terminal on said one face of the Circuit board, the third to fifth connection and the first connection part in the shape of a rectangle so are arranged so that the second connection part is located in its interior, through the first contact surface a first projection is formed, which is formed out of the dome adjacent its circumference, the dome is formed with a second, a third and a fourth protrusion adjacent its periphery, which Projections against the third, fourth and fifth switch- ■ terminal abut, from the circumference of the dome of one surface of the circuit board and of the aforementioned Conductors are at a distance, the second · contact surface by a molded from the inside of the dome fifth protrusion is formed. 19. Key switch panel according to claim 18, characterized in that that the switching element is substantially rectangular with arcuate corners leading to the center of the The tips are coaxial, the first to fourth protrusions being formed at the corners mentioned. - 21 - A09829 / 0972 20. Key switch panel according to claim 1, characterized in that said one surface of the circuit board at least one third conductor between the first and the second conductor and at a distance from them and in substantially the same plane as this, which third conductor is below the switching element extends away from a point on the mentioned one surface, the switching element in its bent position is from the third conductor at a distance, with no electrical connection between the third conductor and the switching element in whose positions exist. 21. Iast switch panel according to claim 20, characterized in that that the mentioned switching element is a snap action dome, the second contact surface in the middle of the dome is located, the third conductor between the first and the second connection part is provided in substantially the same plane as this. 22. Key switch panel according to claim 1, characterized in that said one surface of the circuit board carries a third conductor which at least partially surrounds the second connection part, at a distance therefrom and is essentially in the same plane as this one, the surface of the switching element surrounding the second contact surface is in contact with the third conductor, when the switching element is bent further after the second contact has been made with the second connection part is to thereby protect the switching element and the second contact surface. For: BOWMAR INSTRUMENT CORP. PAIWTANWXLTE 0 «.-» ». H.PINCKE, DIPL-ING. Η BOHB _ 22 - WPWNG. S. 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