US3714611A - Solid state switch construction - Google Patents

Solid state switch construction Download PDF

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Publication number
US3714611A
US3714611A US00199872A US3714611DA US3714611A US 3714611 A US3714611 A US 3714611A US 00199872 A US00199872 A US 00199872A US 3714611D A US3714611D A US 3714611DA US 3714611 A US3714611 A US 3714611A
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US
United States
Prior art keywords
core
switch
magnetic
magnetic core
switch body
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.)
Expired - Lifetime
Application number
US00199872A
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English (en)
Inventor
R Madland
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.)
Illinois Tool Works Inc
Original Assignee
Illinois Tool Works Inc
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 Illinois Tool Works Inc filed Critical Illinois Tool Works Inc
Application granted granted Critical
Publication of US3714611A publication Critical patent/US3714611A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/965—Switches controlled by moving an element forming part of the switch
    • H03K17/97—Switches controlled by moving an element forming part of the switch using a magnetic movable element
    • H03K17/972—Switches controlled by moving an element forming part of the switch using a magnetic movable element having a plurality of control members, e.g. keyboard

Definitions

  • keystem has a pair of legs extending on opposite sides I of the magnetic core with two permanent magnets [2]] Appl' l99872 secured thereto.
  • the magnets are located adjacent opposite sides of the U.S. core so that the magnetic flux path is formed through [5 the magnetic core the keystem and the two per- Fleld Search 197/98; l79/90l C; manent magnets to thereby saturate the magnetic core 340/365 347 and prevent transformer coupling.
  • This invention relates generally to a solid state switch construction, and more particularly to a switch construction suitable for use in keyboards utilized for feeding information into data processing equipment.
  • keyboards are well known for use with data processing'equipment to feed in signal information corresponding to some particular code. Such keyboards may'take many forms, they being either provided with electronic switches or mechanical switch components.
  • One well known type of keyboard comprises a plurality of electric switch contacts mechanically operated by depressing a keystem.
  • the keystem may have a coded top face with a letter or number or the like.
  • These devices suffer many disadvantages in that they are subject towear and the contacts tend to cause high resistance due to arcing or oxidization thereof. Also, atmospheric conditions may cause unreliable switching of these components due to dirt that may enter the keyboard.
  • Solid state switches have been developed for such keyboards and have generally overcome the above disadvantages of mechanically actuated electrical switch contacts.
  • One form of solid state switch comprises a permanent magnet and a core associated therewith.
  • the permanent magnet, or the core is fastened to a keystem or actuating member to move the core and magnet relative to one another.
  • the core is generally provided with a drive winding wire and a sense wire threaded therethrough. An AC signal is applied to the drive winding. .
  • the switch actuator is in the undepressed condition, the permanent magnets are positioned on each side of the core and the effective impedance is relatively low and no transformer coupling can take place between the drive wire and the sense wire.
  • Another object of this invention is to provide an improved solid state switch construction wherein the switch body is readily mounted into large keyboard assemblies for data processing equipment and wherein replacement of defective switches is easily accomplished without unwiring the wires that are through the magnetic core within the switch body.
  • the solid state switch construction of this invention is an improvement over application Ser. No. 879,220 filed on Nov. 24, 1969, now U.S. Pat. No. 3,638,221 which is assigned to the assignee of the present application.
  • a relatively large number of switches are mounted in a housing to form a keyboard for data processing equipment.
  • Such keyboards are commonly used to feed information into the electronic circuitry of computers.
  • Such computers require pulse signal information at rapid rates and over long periods of time to do the necessary manipulation of the data and produce the desired result. Therefore, keyboard switches are actuated substantially continuously over long periods of time and are often in need of repair.
  • One type of failure is that of the switch body components, they being the actuating mechanism itself or the arms carrying the permanent magnets within the switch body.
  • the solid state switch construction of this in- .vention includes a magnetic core which is relatively loosely received within the switch body and firmly but removably held therein by a small metal clip.
  • the switch body is then inserted through a wall of a keyboard for mounting the same in a conventional manner and the wires passing through the magnetic core is wired into the computer circuitry.
  • the switch body components can be removed from the keyboard housing without unwiring of the windings passing through the magnetic core. To remove the switch body from the keyboard housing, it is necessary to gain access to the underside of the keyboard.
  • a further improvement of the switch construction of this invention is that the retaining clip is of paramagnetic material and functions to provide a magnetic shunt between thepermanent magnets to further substantially aid in unsaturating the magnetic core so that AC signal coupling can occur between the drive and sense wires about and through the core which may act as a transformer coupled device.
  • FIG. 1 is an exploded view of a solid state key switch constructed in accordance with the principles of this invention
  • FIG. 2 is a plan view of a portion of a keyboard illustrating four key switches extending upwardly therefrom to be actuated for applying signals to a data processing machine;
  • FIG. 3 is an elevational end view of the solid state switch extending through the top wall of the keyboard housing and which shows, in phantom lines, the flexure of the switch body to remove a retaining clip for disassembling a magnetic core member from the switch body;
  • FIG. 4 is an elevational side view of the solid state switch extending through the top wall of a keyboard housing showing the magnetic core member having the wires thereof extending outwardly for connection into a circuit;
  • FIG. 5 is a view showing the switch body removed from the keyboard and disassembled from the magnetic core which remains beneath the top wall of the keyboard housing;
  • FIG. 6 is an enlarged bottom view of the switch construction of FIG. 1 showing the relative placement of the retainer clip and magnetic core;
  • FIG. 7 is a sectional view taken along line 7-7 of FIG. 6'.
  • FIGS. 8 and 9 illustrate the relative position of the permanent magnets within the switch body relative to the magnetic core for saturating and unsaturating the core to effect a switching action.
  • FIG. 1 there is seen an exploded view of a solid state switch constructed in accordance with the principles of this invention and is designated generally by reference numeral 10.
  • the solid state switch 10 is formed of a switch body 12 into which is inserted a keystem 14 over a coil spring 16 which resiliently urges the keystem l4 upwardly in a deactuated condition when assembled.
  • the keystem 14 is confined at theupper end by a top wall member 18 which is secured within a recess 19 of the key body 12 by ultrasonically welding or other suitable means.
  • a pair of permanent magnets 20 and 22 are firmly held by spaced apart legs 21 and 23, respectively, of the keystem l4 and are movable therewith.
  • the magnets 20 and 22 may be insert molded in the keystem.
  • the magnetic core 24 is firmly but removably held within the switch body by a removable clip 32 which frictionally engages the interior side walls of the switch body when assembled. Upon removal of the clip 32 the entire switch body structure can be removed from the magnetic core 24 and its associated wires 26 and 28 without necessitating disconnecting of the leads from the-electric circuitry to which they are connected.
  • the switches 10 may be part of a switch matrix in a ten-by-ten, or any other suitable XY configuration, and may include indicia caps secured to the top of the keystem 14 so that letters or numbers may be displayed.
  • FIG. 3 illustrates the switch 10 secured to the top wall 34 and further illustrates the side flexure of leg portions 38 and 40 in diametrically opposed directions, as shown by the broken line, to allow simple removal of the clip 32 from within the recess 30.
  • the holding tabs 33, FIG. 1 are squeezed together to remove the switch body 12 upwardly and the magnetic core 24 can be dislodged from its position within the switch body 12 without requiring the disconnection of the wires 26 and 28 from the circuits.
  • FIGS. 4 and 5 The switch 10 is shown in FIG. 4 with the magnetic core 24 located between the permanent magnets 20 and 22 within the switch body 12 and with the magnetic core 24 held firmly therein by the removable clip 32.
  • FIG. 5 shows the switch body 12, together with its keystem l4 and other associated components, completely removed from the top wall 34 of the keyboard so that the magnetic core 24 and its associated wires 26 and 28 remain below the keyboard wall 34 in continuous electrical connection with its associated circuitry. Therefore, none of the electrical circuitry of the data processing equipment is disturbed, and little or no down time will be experienced.
  • the bottom view of the switch 10 is shown and the leg portions 38 and 40 of the switch body 12 are shown as being hollow to receive the permanent magnets 20 and 22 movable therein.
  • the magnetic core 24 is located centrally within the switch body 12 and engages an enlarged portion 41 of the clip 32 which is substantially in the middle of the clip.
  • Outwardly extending gripping end portions 42 and 44 are formed on the clip 32 to dig into the material of the switch body and thereby be firmly held in place. This is best illustrated in FIG. 3 which shows the gripping end portions 42 slightly embedded in the material of the switch body. Therefore, outward flexure of the leg portions 38 and 40, as shown in FIG. 3, -will facilitate removal of the clip 32 for removing the magnetic core.
  • gripping end portions 42 and 44 may engage recesses 43 and 45, respectively, formed within the switch body as shown in FIG. 7.
  • the clip 32 is held in position by being confined at its lower end by the recesses and confined at its upper end by the presence of the core member 24.
  • FIGS. 8 and 9 illustrate the operating condition of the keystem 14 relative to the magnetic core 24.
  • the keystem is in a deactuated up position and the permanent magnets 20 and 22 are positioned immediately adjacent the magnetic core 24 to completely saturate the magnetic material thereof.
  • the retaining clip 32 has little or no effect on diverting magnetic flux from passing through the magnetic core 24.
  • the permanent magnets 20 and 22 are moved downwardly and the magnetic core 24 is substantially freed of all magnetic flux and AC coupling can take place to cause a switching action.
  • the retaining clip 32 is constructed of paramagnetic material and now acts as a magnetic shunt between the permanent magnets and 22 and the magnetic core 24 further to insure the switching action. Any stray magnetic flux which would tend to enter the magnetic core 24 will be shunted by the metal clip 32.
  • This feature helps to create a more finite switching position or condition of the solid state switching device as the keystem 14 is moved downward. That is, the keystem 14 moves downward to a definite position whereupon magnetic flux is quickly diverted from the magnetic core 24 and fast switching is accomplished by instantaneous transformer coupling between the drive and sense wires 26 and 28.
  • the invention is claimed as followsi 1.
  • a switch body having a recess, a core of magnetic material positioned within said recess, at least two winding means passing through said core to have the ends thereof electrically connected in a circuit when said switch body is mounted to a keyboard, movably mounted permanent magnet means positioned within said switch body closely adjacent said core to saturate said core when in one position and to be moved away from said core to unsaturate the same when in another position, and clip means removably secured to said switch body over said recess firmly but removably to hold said core within said recess and to allow removal of said core from said switch body without disconnecting said winding means from the circuit to which it is connected when said switch body is removed from the keyboard.
  • a keyboard switch comprising, a saturable magnetic core, a depressable keystemhavin first and second legs extending on opposite sides 0 said core,
  • first and second permanent magnets mounted on said first and second legs, respectively, each permanent magnet being mounted on its corresponding leg intermediate the leg and said magnetic core, said permanent magnets being positioned on said legs to be opposite said core when the keystem is not depressed, whereby a flux path is established from one said magnet to the other said magnet, and through said core to saturate the same, said keystem carrying said permanent magnets out of saturating relation with said core when said keystem is actuated, and clip means removably engaged with said magnetic core to hold said magnetic core within said keyboard switch and to allow removal of said magnetic core without disconnecting the core from its associated electronic circuitry.
  • a keyboard comprising, a plurality of keyboard switches each having an active and an inactive state and including, a saturable magnetic core having a closed loop magnetic flux path, a movable keystem having leg portions on opposite sides of said magnetic core, first and second permanent magnets secured to said legs and movable with said keystem to saturate said core when said switch is in one of said states with the flux passing through said magnetic core and to unsaturate said magnetic core when the switch is in the other of said states, coupling winding means positioned about said core to be connected in circuit with associated circuitry, and clip means removably holding said magnetic core and its associated windings into the keyboard switch to allow removal of the keyboard switch from said magnetic core and its associated windings without necessitating disconnecting of the windings from its circuitry.
  • said clip means is formed of a flat piece of paramagnetic material to form a magnetic shunt path with said core to divert the magnetic flux from said permanent magnets when said switch is in its active state.
  • said clip means is formed of a flat piece of material having outwardly extending end portions to be engaged into recesses formed in the switch body.

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  • Input From Keyboards Or The Like (AREA)
  • Push-Button Switches (AREA)
US00199872A 1971-11-18 1971-11-18 Solid state switch construction Expired - Lifetime US3714611A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US19987271A 1971-11-18 1971-11-18

Publications (1)

Publication Number Publication Date
US3714611A true US3714611A (en) 1973-01-30

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00199872A Expired - Lifetime US3714611A (en) 1971-11-18 1971-11-18 Solid state switch construction

Country Status (10)

Country Link
US (1) US3714611A (OSRAM)
JP (1) JPS4863637A (OSRAM)
AU (1) AU455620B2 (OSRAM)
CA (1) CA984051A (OSRAM)
CH (1) CH549835A (OSRAM)
DE (1) DE2251676A1 (OSRAM)
FR (1) FR2160515B2 (OSRAM)
GB (1) GB1346128A (OSRAM)
IT (1) IT970930B (OSRAM)
NL (1) NL7214592A (OSRAM)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4017850A (en) * 1976-02-02 1977-04-12 Illinois Tool Works Inc. Magnetic keyswitch with two-piece support assembly
US4099176A (en) * 1974-05-30 1978-07-04 Illinois Tool Works Inc. Magnetic key switch having a removable support assembly
US4334204A (en) * 1980-06-30 1982-06-08 The Boeing Company Proximity switch assembly
US4379973A (en) * 1981-05-20 1983-04-12 C & K Components, Inc. Universal logic switch

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3300797A1 (de) * 1983-01-12 1984-07-12 E.G.O. Elektro-Geräte Blanc u. Fischer, 7519 Oberderdingen Befestigungseinrichtung fuer eine steuereinrichtung
DE3678620D1 (de) * 1985-06-15 1991-05-16 Ego Elektro Blanc & Fischer Befestigungsvorrichtung zur halterung von funktionsgeraeten o. dgl.

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099176A (en) * 1974-05-30 1978-07-04 Illinois Tool Works Inc. Magnetic key switch having a removable support assembly
US4017850A (en) * 1976-02-02 1977-04-12 Illinois Tool Works Inc. Magnetic keyswitch with two-piece support assembly
US4334204A (en) * 1980-06-30 1982-06-08 The Boeing Company Proximity switch assembly
US4379973A (en) * 1981-05-20 1983-04-12 C & K Components, Inc. Universal logic switch

Also Published As

Publication number Publication date
GB1346128A (en) 1974-02-06
CH549835A (fr) 1974-05-31
DE2251676A1 (de) 1973-05-24
AU4784372A (en) 1974-04-26
AU455620B2 (en) 1974-11-21
IT970930B (it) 1974-04-20
FR2160515A2 (OSRAM) 1973-06-29
NL7214592A (OSRAM) 1973-05-22
FR2160515B2 (OSRAM) 1979-02-02
CA984051A (en) 1976-02-17
JPS4863637A (OSRAM) 1973-09-04

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