EP0637830A2 - Elektrischer Schalter mit ineinandergreifenden und überbrückendenKontaktstellen. - Google Patents

Elektrischer Schalter mit ineinandergreifenden und überbrückendenKontaktstellen. Download PDF

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Publication number
EP0637830A2
EP0637830A2 EP94302841A EP94302841A EP0637830A2 EP 0637830 A2 EP0637830 A2 EP 0637830A2 EP 94302841 A EP94302841 A EP 94302841A EP 94302841 A EP94302841 A EP 94302841A EP 0637830 A2 EP0637830 A2 EP 0637830A2
Authority
EP
European Patent Office
Prior art keywords
pole
poles
keypad
switches
switch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94302841A
Other languages
English (en)
French (fr)
Other versions
EP0637830A3 (de
Inventor
Yoshio Shimono
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fluke Corp
Original Assignee
Fluke Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fluke Corp filed Critical Fluke Corp
Publication of EP0637830A2 publication Critical patent/EP0637830A2/de
Publication of EP0637830A3 publication Critical patent/EP0637830A3/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
    • H01H13/702—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2203/00—Form of contacts
    • H01H2203/02—Interspersed fingers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2203/00—Form of contacts
    • H01H2203/036—Form of contacts to solve particular problems
    • H01H2203/042—Form of contacts to solve particular problems to avoid cross-overs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2225/00—Switch site location
    • H01H2225/006—Switch site location more then one pole

Definitions

  • This invention relates generally to switches used in electric circuits and, more particularly, to mechanical switches having multiple poles.
  • Mechanical switches refers to switches that require some sort of physical movement (hence the term mechanical) in order to operate the switch. These switches may be operated either manually or automatically. Examples of mechanical switches include membrane, rotary, pushbutton, slide and toggle switches. Mechanical switches typically consist of a shorting bar and one or more spaced-apart poles connected to electric circuits. Operating the switch causes the shorting bar to either make or break contact with the poles, thereby completing, interrupting, or otherwise changing the connections of the electric circuits.
  • the poles of single and double pole switches are placed on one surface or layer of the switch. It is desirable to do this because it simplifies switch construction. By having the poles on one surface, connecting the poles to electric circuits is greatly simplified.
  • prior art switches having three or more poles usually have the poles located, at least partially, on more than one layer of the switch. Sometimes, for example, the shorting bar acts as the third pole in a three pole membrane switch.
  • the disadvantage associated with this type of pole arrangement is that the poles are on different layers and must somehow be combined on one layer so that they can be easily terminated at a single connector. Jumpers can be used to place the poles on one surface or multiple connectors could be used. Unfortunately, both approaches increase the complexity and cost of manufacturing the switch.
  • the present invention directed to an electric switch having a through pole located on the same surface as other switch poles, is designed to achieve these results.
  • the present invention provides an electrical switch comprising first and second interdigitated poles located on a support member and a third pole passing therebetween to form a through pole also located on the support member such that the third pole does not box-in the first and second poles.
  • a conductive member is in a movable relationship with the poles and support member, such that movement of the conductive member causes it to make or break contact with the poles.
  • a keypad incorporating a plurality of the switches includes a plurality of interdigitated first and second poles located on a keypad support member and a third pole passing therebetween to form a through pole also located on the keypad support member.
  • a plurality of conductive members associated with the plurality of switches are in movable relationship with the poles and keypad support member, such that movement of any of the conductive members causes it to make or break contact with the poles of the associated switches on the keypad support member.
  • the present invention provides an electrical switch having interdigitated poles and a through pole passing therebetween and a keypad comprising such switches.
  • Fig. 1 illustrates a portion of a prior art keypad 10 encompassing conventional three-pole membrane switches 14 and 114 connected in a single common pole configuration.
  • the top layer of keypad 10 is removed for purposes of clarity and to better illustrate important features of the switches.
  • Switch 14 includes three poles 16, 18 and 20.
  • Pole 16 is in the form of a shoring pad affixed to the underside of the top layer of the keypad (removed) and is represented by a dashed outline.
  • poles 18 and 20 are located on the top surface of base layer 12, directly behind pole 16 and are spaced apart from pole 16.
  • Pole 16 is brought out to the edge of the keypad by conductive trace 26, also located on the underside of the top layer of the keypad (and therefore represented as a dashed line).
  • Poles 18 and 20 include interdigitated fingers 22 and 24, respectively, and are brought out to the keypad's edge via traces 28 and 30, respectively.
  • switch 114 includes poles 116, 118 and 120 similarly situated in keypad 10. Poles 118 and 120 are brought out to an edge via traces 128 and 130.
  • Pole 116 is connected in common to pole 16. More particularly, pole 116 is connected to trace 26 via trace 126.
  • switches 14 and 114 The operation of prior art switches 14 and 114, is well understood by persons having ordinary skill in the electrical field, and therefore is not discussed in detail herein. Briefly, however, by pressing down on the top of switch 14, pole 16 is brought into contact with poles 18 and 20 and causes an appropriate response in electrical circuits (not shown) that are connected to traces 26, 28 and 30. Switch 114 works in a similar manner.
  • a keypad utilizing multiple switches of the sort illustrated in Fig. 1 all of the traces are typically brought to one edge of the pad for termination onto a connector for connection to other electric circuits.
  • trace 26 is on a different layer than traces 28, 30, 128 and 130. If the traces are not somehow brought to the same surface of the same layer, it will be necessary to use two connectors (i.e., one connector for the traces on each layer). As can be appreciated, it is undesirable to use two connectors because they increase the number of components in the keypad, thereby raising its complexity, and cost. Alternatively, the traces may be jumpered to one layer so that only one connector is required. Jumpers are undesirable, however, in that they add to the complexity of manufacturing the keypad and increase its cost.
  • Fig. 2 illustrates another prior art keypad 40 incorporating conventional three-pole membrane switches 42 and 142 connected in a single common pole configuration.
  • the pole layout of switches 42 and 142 is different than in the membrane switches of Fig. 1.
  • switch 42 and 142 all three poles of each switch are located on the same layer 41 of the keypad. More specifically, switch 42 consists of poles 44 and 46 with interdigitated fingers 52 and 54, respectively.
  • Third pole 48 lies outside and boxes in the other poles. Poles 44, 46 and 48 are brought out to the edge of the keyboard via traces 60, 62 and 64, respectively.
  • switch 142 includes poles 144 and 146 that have interdigitated fingers 152 and 154, respectively, and are brought out to the edge of the keypad via traces 160 and 162, respectively.
  • Third pole 148 is connected in common with pole 48 via trace 58.
  • Third poles 48 and 148 include multiple jumpers 56 and 156 so as to avoid touching the other poles.
  • the jumpers may be discrete wires soldered to the traces.
  • the jumpers may consist of plated through holes and traces on the other surface of the base layer 41.
  • jumpers 56 and 156 may be formed as traces on the underside of layer 41 and connected to the trace forming the third pole via plated through holes in layer 41.
  • jumpers are undesirable in that they add to the complexity of manufacturing the keypad and thereby increase the cost of the keypad.
  • Switch 70 includes a top layer (not shown in this figure for reasons of clarity, but illustrated in Fig.4) and base layer 72.
  • Shorting pad 74 is preferably formed on the underside of the top layer of the switch and is represented by a dashed outline.
  • Base layer 72 has located thereon three poles 76, 78 and 80. Poles 76 and 78 include spaced apart, interdigitated fingers 82 and 84, respectively.
  • Third pole 80 which forms a through pole of switch 70, is spaced apart from poles 76 and 78 and meanders on base layer 72 such that it passes between the interdigitated fingers of poles 76 and 78. In this regard, pole 80 passes through switch 70.
  • Shorting pad 74 is normally spaced apart from poles 76, 78 and 80, such that when an operator presses the membrane switch, the shorting bar is brought into contact with all three poles.
  • interdigitated fingers 82 and 84 and the meandering path of through pole 80 provide a high density contact area for shorting bar 74.
  • the high density layout of the switch poles ensures proper contact when the switch is pressed, even if only a relatively small area of the shorting bar makes contact with the poles. For example, even if an operator presses down on a corner of the switch or uses an object such as a pen to depress the switch, the poles are close enough together that the shorting bar will be brought into contact with all three poles.
  • the poles are formed by any one of the number of conventional printed circuit board processes, such as photo-etching or vapor deposition, for example.
  • the poles are preferably silver traces, but may consist of any electrically conductive material formed, mounted or otherwise attached to an electrically insulating substrate making up base layer 72.
  • Base layer 72 may be rigid or flexible and, for example, may consist of mylar or polyester.
  • Fig. 4 is a section view of switch 70 taken along section line 4-4 in Fig. 3.
  • base layer 72 supports interdigitating fingers 82 and 84 of poles 76 and 78, respectively, and through pole 80.
  • Shorting pad 74 is affixed, mounted or otherwise attached to top layer 71 and is spaced apart from the poles and base layer 72 by spacer 73.
  • switch 70 may be operated in a conventional manner by pressing down on top layer 71 and thereby bringing shorting pad 74 into contact with the three poles (76, 78 and 80) on base layer 72.
  • Fig. 5 illustrates a four pole membrane switch 70' according to the preferred embodiment of the present invention. Since switch 70' is substantially identical to switch 70 (Fig. 3), with the exception of a fourth pole, the common elements between the two figures are numbered similarly, with the exception being that the reference numbers in Fig. 5 are primed. As previously mentioned, the sole difference between switches 70 and 70' is that the latter has a fourth pole, represented as through pole 86. Through pole 86, like through pole 80', is spaced apart from, and meanders through, the fingers 82', 84' of poles 76' and 78', respectively. All four poles are located on base layer 72'.
  • an electrical switch includes at least one through pole that meanders between the fingers of two other poles of the switch.
  • the poles are located on the same surface of a supporting, or base, layer of the switch.
  • the poles are essentially coplanar since they reside on the same surface of a substantially flat substrate.
  • electrical switches other than membrane switches may utilize the present invention.
  • rotary switches having poles on a printed circuit board could also benefit from the pole layout of the present invention.
  • a keypad 200 having an array of three-pole membrane switches of the kind depicted in Fig. 3 and discussed above.
  • the switches are connected in a single common pole configuration, such as might be found in applications where, for example, an interrupt signal is to be supplied to a microprocessor every time one of the switches is pressed.
  • all three poles of the switches are located on one layer of the keypad and as a result all poles may be readily terminated at a single connector at the edge of the keypad.
  • keypad 200 comprises a base layer 202, an array of three pole membrane switches 204-230, and conductive traces bringing switch poles to an edge of the keypad.
  • the three poles of each switch 204-230 are labeled "a", "b” and "c".
  • Each pole may be specifically identified by combining the reference number of the switch with the label of the particular pole.
  • pole "a” of switch 204 may be represented as pole 204a and pole "c" of switch 226 becomes pole 226c.
  • the conductive traces are identified by 300 series reference numerals corresponding to each switch.
  • a trace connected to pole "a” or "b” of a particular switch has the pole designation associated with its reference numeral.
  • the trace connected to pole 204a is designated 304a and the trace connected to pole 226b is designated 326b.
  • the through poles i.e., the "c" poles in Fig. 6 are connected together, thus forming the single common pole of key pad 200.
  • the trace segments connecting all "c" poles and bringing them to the edge of the keypad are designated collectively as 300c.
  • the poles of the switches are routed to the edge of the keypad without crossing one another or leaving the surface of base layer 202. This is because the meandering nature of through pole "c" does not box in the other poles of the switches, as does the prior art three-pole switch configuration illustrated in Fig. 2 and discussed above. As a result, the traces can be readily connected to a single connector for coupling to other circuits.
  • FIG. 7 there is illustrated a keyboard having an array of switches according to a preferred embodiment of the present invention (as depicted in Fig. 3) with a different pole configuration than is illustrated in Fig. 6 and discussed above.
  • Figs. 6 and 7 have the similar reference numerals, except that the numerals in Fig. 7 are primed.
  • Elements in Fig. 7 that are substantially different are given unique numbers and are not primed.
  • Key pad 200' includes base layer 202', having located thereon poles a', b' and c' of an array of membrane switches 204'-230'. As with keypad 200 in Fig. 6, the b' poles of switches 204'-230' are brought out to an edge of the keypad via traces 304b'-330b', and through poles (c') of the switches are interconnected and brought out to the edge via trace 300c'.
  • Keypad 200' differs from the switch in Fig. 6 in that it has a second pole of the switches connected in common. Specifically, the a' poles of switches 204'-230' are interconnected and brought out to the edge of the keypad via trace 300a. Hence, the switches of keypad 200' have a double common pole configuration. As is readily clear from Fig. 7, poles of the various switches are located on the same surface of base layer 202' and are brought out to the edge without crossing one another. This is possible because the through pole (c') meanders between, and does not box in, the other poles of the switches.
  • FIG. 8 there is illustrated an elevational view of keypad 200' as viewed from an edge along line 8-8 in Fig. 7.
  • Connector 90 (not shown in Fig. 7) is coupled to the traces that are brought out to the edge of the keypad 200'.
  • the traces (300a, 300c', 304b', 306b', 314b', 324b', 326b', 328b' and 330b') correspond to the traces having the identical reference numerals in Fig. 7.
  • Connector 90 is preferably an elastomeric type of interconnector having conductors imbedded within the elastomeric material for connecting the keypad to other electric circuitry.
  • connector 90 includes imbedded conductors that correspond to the traces at the edge of the base layer.
  • Conductors 400a, 400c', 404b', 406b' - 414b', 424b', 426b', 428b' and 430b' are embedded in conductor 90 and are in contact with the traces on base 202' when the connector is in place on the keypad.
  • trace 300a is connected to conductor 400a, trace 300c' to conductor 400c', etc.
  • Elastomeric interconnectors are preferred in many applications, in part, because they are relatively inexpensive, and are readily adaptable to Z-axis manufacturing techniques.
  • connector 90 is not limited to elastomeric interconnectors and may be any type of connector suitable for use with electrical conductors.
  • Figs. 9 and 10 illustrate alternative embodiments of the present invention. Elements appearing in Figs. 9 and 10 that are substantially the same, or perform substantially the same function, as elements in the switch shown in Fig. 3, are numbered the same, except that the reference numerals include either an "a" (Fig. 9) or a "b" (Fig. 10). For reasons of simplicity, and to avoid duplication, some elements of the switches are omitted, such as the supporting base layer, but is to be understood that such elements form a part of the switches depicted in Figs. 9 and 10. In Fig. 9, poles 76a and 78a have interdigitated fingers 82a and 84a forming planar, concentric open circles.
  • Through pole 80a is planar with, and meanders between, the other poles.
  • poles 76b and 78b have interdigitated fingers 82b and 84b forming a planar, zig-zag pattern with through pole 80b being planar with, and meandering between, the other poles.
  • the switch of the present invention having one or more through poles meandering through interdigitated poles is well suited for use in a keypad having an array of switches connected in either a single or double common pole configuration.
  • a switch according to the present invention permits the poles and traces connected thereto to be located on the same surface of one supporting layer and to be brought out to an edge of a keypad for termination at a single connector.
  • poles of the switch could have numerous configurations other than those illustrated and discussed herein.
  • number of poles may vary and are limited primarily by physical limitations of the switch.
  • the preferred and alternative embodiments of the present invention have been discussed in terms of membrane switches, it is to be understood that the present invention may be practiced with other kinds of switches, such as rotary, toggle, and slide switches. Consequently, the invention can be practiced otherwise than as specifically described herein.

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  • Push-Button Switches (AREA)
EP94302841A 1993-07-20 1994-04-21 Elektrischer Schalter mit ineinandergreifenden und überbrückendenKontaktstellen. Withdrawn EP0637830A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US9511393A 1993-07-20 1993-07-20
US95113 1993-07-20

Publications (2)

Publication Number Publication Date
EP0637830A2 true EP0637830A2 (de) 1995-02-08
EP0637830A3 EP0637830A3 (de) 1995-06-14

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ID=22249759

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EP94302841A Withdrawn EP0637830A3 (de) 1993-07-20 1994-04-21 Elektrischer Schalter mit ineinandergreifenden und überbrückendenKontaktstellen.

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EP (1) EP0637830A3 (de)
CA (1) CA2121966A1 (de)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3688066A (en) * 1970-12-30 1972-08-29 Wild Rover Corp Switch forms for connecting one terminal to a plurality of other terminals
US3761944A (en) * 1971-01-22 1973-09-25 Alps Electric Co Ltd Binary code generator
US4501938A (en) * 1982-04-09 1985-02-26 Alps Electric Co., Ltd. Keyboard switch
US4647729A (en) * 1985-10-04 1987-03-03 Northern Telecom Limited Circuit board with contact positions, as used for telecommunications terminals and other apparatus
US4652704A (en) * 1985-12-30 1987-03-24 Sperry Corporation Keyboard switch

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3688066A (en) * 1970-12-30 1972-08-29 Wild Rover Corp Switch forms for connecting one terminal to a plurality of other terminals
US3761944A (en) * 1971-01-22 1973-09-25 Alps Electric Co Ltd Binary code generator
US4501938A (en) * 1982-04-09 1985-02-26 Alps Electric Co., Ltd. Keyboard switch
US4647729A (en) * 1985-10-04 1987-03-03 Northern Telecom Limited Circuit board with contact positions, as used for telecommunications terminals and other apparatus
US4652704A (en) * 1985-12-30 1987-03-24 Sperry Corporation Keyboard switch

Also Published As

Publication number Publication date
CA2121966A1 (en) 1995-01-21
EP0637830A3 (de) 1995-06-14

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