US3748626A - Miniaturized potentiometer - Google Patents

Miniaturized potentiometer Download PDF

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Publication number
US3748626A
US3748626A US00278865A US3748626DA US3748626A US 3748626 A US3748626 A US 3748626A US 00278865 A US00278865 A US 00278865A US 3748626D A US3748626D A US 3748626DA US 3748626 A US3748626 A US 3748626A
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US
United States
Prior art keywords
potentiometer
slider
casing
actuating member
insulating support
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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
US00278865A
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English (en)
Inventor
J Maurice
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.)
FR L ELECTRO RESISTANCE SOC
SOC FR L ELECTRO RESISTANCE FR
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FR L ELECTRO RESISTANCE SOC
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Publication date
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Publication of US3748626A publication Critical patent/US3748626A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C10/00—Adjustable resistors
    • H01C10/005—Surface mountable, e.g. chip trimmer potentiometer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C1/00—Details
    • H01C1/02—Housing; Enclosing; Embedding; Filling the housing or enclosure
    • H01C1/024—Housing; Enclosing; Embedding; Filling the housing or enclosure the housing or enclosure being hermetically sealed
    • H01C1/026—Housing; Enclosing; Embedding; Filling the housing or enclosure the housing or enclosure being hermetically sealed with gaseous or vacuum spacing between the resistive element and the housing or casing

Definitions

  • a rotary-contact potentiometer which is primarily intended to be employed in miniaturized hybrid circuits. It comprises a metallic casing which contains the rotary [30] Foreign Apphcauon Priority Data slider and its actuating member and a circular resistive Aug. 31, France track deposited on an insulating pp
  • the casing has an open structure and is provided on one of its [52] US. Cl. 338/162, 338/18; faces with a circular opening for guiding and centering [5 ..3..3..-..i.... the slider actuating member.
  • This invention relates to a rotary-contact potentiometer, especially of the miniature type which is primarily intended to be employed in hybrid and integrated circuits.
  • the object of the present invention is to produce a potentiometer of rugged construction which readily permits large-scale manufacture in spite of its very small dimensions, with the result that all operations which are necessary for integration of the potentiometer in hybrid circuits are thus made possible, especially when said integration entails the well-known remelting method followed by ultrasonic cleaning in an organic solvent.
  • a further object of the invention is to permit selection of the potentiometer components from conductive and insulating materials which are capable of withstanding the temperatures attained at the time of application of the remelt technique without any attendant danger and which must be insensitive to the action of the solvents usually employed at the time of ultrasonic cleaning.
  • Yet another object of the invention is to permit cleaning of the internal portions of the potentiometer before or after mounting of this latter on the hybrid circuit. In fact, by reason of the small dimensions of a potentiometer of this type as well as the low electric currents circulating within said circuits, the slightest superficial alteration of the active portions of the potentiometer is liable to give rise to appreciable modification of the resistance between the terminals, thereby resulting in failure of the entire circuit.
  • the rotary-contact potentiometer which is primarily intended to be employed in miniaturized hybrid electric circuits and comprises a metallic casing which contains the rotary slider and its actuating member and a circular resistive track deposited on an insulating support, is characterized in that the casing has an open structure and is provided on one of its faces with a circular opening for guiding and centering the slider-actuating member and that the face opposite to said opening is the external face of the insulating support of the resistive track, three metallized zones which are separate from each other being formed on said face of the insulating support for fixing the potentiometer in position and establishing electrical connections between the potentiometer and the electric circuit.
  • the openings formed in the casing make it possible both to facilitate the assembly of the different components of the potentiometer and make these latter accessible to the cleaning solvent.
  • At least a number of the following components casing, slider and slider-actuating member are constituted by sheetmetal elements which are cutout, bent and/or diestamped.
  • the casing is preferably provided with a plurality of lugs which are folded-back towards the interior of this latter parallel to the face in which the circular opening is formed and applied both against the external face of the insulating support of the resistive track and against the internal face thereof.
  • At least one of the lugs of the casing is applied against the external face of the insulating support, is placed over one of the three metallized zones of the insulating support and constitutes one of the output terminals of the potentiometer, the two other metallized zones being connected to the extremities of the circular resistive track by means of two conductive members which constitute the two other output terminals of the potentiometer.
  • Bending of the casing as contemplated by the invention permits positioning of the resistive track support without having recourse to methods of assembly such as clipping, crimping or bonding. Moreover, the aforesaid positioning of the resistive track support within the casing does not entail any modification of the shape of this latter, with the result that materials having high mechanical strength can be employed in the fabrication of the casing which is thus endowed with a very high degree of ruggedness.
  • the conductive members can be of variable shapes and sizes adapted to the configuration of the circuit with which the potentiometer is intended to be integrated.
  • FIG. 1 is a view in perspective showing one embodiment of the potentiometer
  • FIGS. 2 and 3 are two views in perspective of the slider-actuating member, looking respectively on one face and on the other face after said member has been rotated through
  • FIGS. 4 and 5 are two views in perspective showing the casing after this latter has been rotated through 180
  • FIG. 6 is a view in perspective of the slider
  • FIG. 7 is a view in perspective of the resistive track support
  • FIGS. 8 and 9 are two views in perspective of the two conductive members which constitute two output terminals of the potentiometer
  • FIG. 10 is an alternative form of a member shown in FIG. 8
  • FIG. 11 is a bottom plan view of the potentiometer
  • FIG. 12 is a view in elevation showing one of the lateral faces of the potentiometer
  • FIG. 13 is a view in elevation showing another lateral face of the potentiometer
  • FIG. 14 is a top plan view and a half-sectional view taken along line XlV-XIV of FIG. 12
  • FIG. 15 is a view in elevation of the lateral face opposite to that of FIG. 13
  • FIG. 16 is a view in perspective showing the protective cap.
  • the potentiometer in accordance with the invention comprises a metallic casing 1 having a number of open portions and provided at the center of one of its faces with a circular opening 2 for guiding and centering the actuating member 3 of the slider 4.
  • the face opposite to said circular opening 2 is the external face of the insulating support 5 of the resistive track 6. As shown in FIG. 1 1, said face has three metallized zones 7, 8, 9 which permit of welding and are preferably tinned for fixing the potentiometer and establishing the electrical connections between this latter and the electric circuit.
  • the casing is preferably formed by cutting-out and bending of a sheet-metal element. This latter is preferably obtained from alloys having good electrical conductivity and high mechanical strength such as nickel silver and beryllium bronze. It is an advantage in addition to coat the casing with a protective layer formed by electrodeposition of a noble metal such as gold.
  • the casing 1 is provided with a plurality of lugs 10, ll, 12, 13 which are bent-back towards the interior of said casing at an angle of 90 and parallel to the face in which the circular opening 2 is formed.
  • the lugs l0, 12, 13 are applied against the external face of the insulating support 5 forming the base of the potentiometer and partially cover the weldable metallic zone 7.
  • the lug 11 is applied against that face of the support 5 which carries the resistive track 6.
  • Said track has an annular shape and the two extremities of this latter are connected to two metallized zones l4, which are preferably tinned.
  • the insulating material which constitutes the support 5 is advantageously a ceramic material having an alumina base and the track 6 is constituted by a deposit of gold alloyed with palladium and applied by silk-screen process.
  • the conductive members l6, 17 are provided in the form of strips bent-back into a U shape and are positioned by clamping so as to cover the weldable zones 8 and 9 located on the outer face of the insulating support 5 as well as the weldable zones 14 and 15 which are connected to the extremities of the resistive track 6.
  • Said conductive members can be provided with extension lugs having variable dimensions according to the configuration of the hybrid circuit on which the potentiometer is to be fixed.
  • An alternative design of these conductive members is given in FIG. 10.
  • Said members are preferably formed of nickel silver which may be coated if necessary with a thin protective layer of gold.
  • the actuating member 3 of the slider 4 is formed by cutting-out and die-stamping a metallic sheet and provided with a circular peripheral projection 19 for guiding and centering which permits pivotal motion of said member within the circular opening 2 of the casing.
  • the actuating member is further provided with lugs 20, 21 and 22 for providing a mechanical coupling between said member and the slider 4. Two of said lugs 20 and 21 are cut from a diametrical slot 23 of said actuating member and are bent-back towards the interior of the casing at an angle of A third coupling lug 22 is also cut from said actuating member, the center of the lug 22 being preferably located at right angles to the extremities of the slot 23.
  • Said actuating member is preferably made of beryllium bronze and the surface of said member is protected against any chemical change by means of an electrodeposited layer of a noble metal.
  • the slider 4 is formed by cutting-out and bending a sheet-metal element.
  • the slider comprises a flat portion 24 having the shape of a circular segment and carrying a resilient tongue 25 which is bent-back towards the interior of the casing.
  • Said tongue 25 is made up of at least three contact fingers which are intended to bear resiliently on the resistive track 6 and to sweep the surface of this latter the contact surfaces thus formed between the fingers and the track are substantially aligned on a straight line which passes through the center of the circle formed by said track.
  • the slider 4 is also provided with a diametrical slot 26 which has the same size as the slot formed in its actuating member 3 and into which penetrate the two coupling lugs 20 and 21 while bearing on the extremities of said slot 26.
  • a slot 27 In order to strengthen the mechanical coupling between the actuating member 3 and the slider 4, there is also formed in said slider a slot 27, the lug 22 of the actuating member 3 being intended to fit within said slot.
  • the diameter of said circumscribed circle is larger than the diameter of the circular opening 2, with the result that the periphery of the circular portion 24 of said slider is applied against the internal edges of the opening 2.
  • the slider 4 is preferably cut from a metallic sheet having a mechanical strength and elastic limit which is compatible with a contact force between the fingers and the resistive track of at least 60 g.
  • a beryllium bronze subjected to heat treatment after cutting-out and bending so as to endow this latter with a Vickers hardness number of the order of 380.
  • the slider 4 which is thus obtained is covered with a protective coating of a noble metal which affords a sufficient degree of resistance to the friction caused at the time of rubbing of the fingers on the track.
  • the slider-actuating member 3 is preferably provided with a projecting lug 28 which is abuttingly applied against a boss 29 carried by the easing 1.
  • the assembly of the above-mentioned elements can be carried out in a particularly simple and rapid manner and practically does not call for the use of any tool.
  • the assembly constitutes a highly compact unit having a very small volume (approximately 0.03 cm in the case of the potentiometer hereinabove described).
  • the potentiometer can then be placed on the circuit in the actual location in which it is intended to perform its function, the potentiometer being finally fixed on the circuit by means of the well-known method of remelting.
  • This remelting operation fixes the potentiometer by welding between the circuit and the conductive members l6 and 17 or the like and the lugs 10, l2, l3 and at the same time effects the welding of the conductive members to the support 5 by means of weldable zones 8 and 9 as well as the welding of the support 5 to the casing at the level of the lugs l0, l2, 13 by means of the weldable zone 7.
  • the circuit element which is fitted with the potentiometer or potentiometers in accordance with the invention can be dipped in a cleaning solvent which may be subjected if necessary to the action of ultrasonic waves in order that all parts of the circuit and of the potentiometer may thus be freed from any dirt, impurity, dust and the like which is liable to affect the reliability of the assembly as thus constituted.
  • Adjustment of the potentiometer is carried out by introducing a tool such as a screwdriver into the slot 23 which. is formed in the actuating member 3 and by causing this latter to pivot until the desired currentvoltage characteristics are obtained.
  • the projecting lug 28 is preferably resilient and is thus capable of bending under the action of an excessive couple exerted on the actuating member 3. As a consequence, it is not possible to damage the travellimiting device which recovers its efficiency as soon as the lug 28 has passed over the stop 29.
  • the aforesaid adjustment entails the need for an insulated tool or screwdriver this can be dispensed with by incorporating with the actuating member an insulating knob which could be engaged, for example, in the slot 23.
  • the potentiometer which is thus secured to its circuit and adjusted is preferably covered with an elastic cap 30 (shown in FIG. 16) which is fabricated from an elastomer material in order to protect the potentiometer against dust particles, chemical changes and mechanical impacts.
  • both the lug 22 of the slideractuating member and the corresponding slot 27 formed in the slider may be dispensed with.
  • a rotary-contact potentiometer which is primarily intended to be employed in miniaturized hybrid electric circuits and comprises a metallic casing which contains the rotary slider and its actuating member and a circular resistive track deposited on an insulating support, wherein the casing has an open structure and is provided on one of its faces with a circular opening for guiding and centering the slider-actuating member and wherein the face opposite to said opening is the external face of the insulating support of the resistive track, three metallized zones which are separate from each other being formed on said face of the insulating support for fixing the potentiometer in position and establishing electrical connections between the potentiometer and the electric circuit.
  • a potentiometer according to claim 1 wherein at least a number of the following components casing, slider and slider-actuating member are constituted by sheet-metal elements which are cut-out, bent and/or die-stamped.
  • a potentiometer according to claim 2 wherein the casing is provided with a plurality of lugs which are folded-back towards the interior of said casing parallel to the face in which the circular opening is formed and applied both against the external face of the insulating support of the resistive track and against the internal face thereof.
  • a potentiometer according to claim 4 wherein the two other metallized zones are connected to the extremities of the circular resistive track by means of two conductive members which constitute the two other output terminals of the potentiometer.
  • a potentiometer according to claim 8 wherein the slider is constituted by a plate carrying a resilient tongue provided with contact fingers, said plate being counter-braced against its actuating member.
  • Miniaturized hybrid electric circuits comprising at least one rotary-contact potentiometer according to claim 1.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Adjustable Resistors (AREA)
US00278865A 1971-08-31 1972-08-08 Miniaturized potentiometer Expired - Lifetime US3748626A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7131510A FR2151512A5 (enExample) 1971-08-31 1971-08-31

Publications (1)

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US3748626A true US3748626A (en) 1973-07-24

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US00278865A Expired - Lifetime US3748626A (en) 1971-08-31 1972-08-08 Miniaturized potentiometer

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US (1) US3748626A (enExample)
DE (1) DE7230513U (enExample)
FR (1) FR2151512A5 (enExample)
GB (1) GB1380747A (enExample)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3876967A (en) * 1972-11-04 1975-04-08 Illinois Tool Works Variable resistor
US3921118A (en) * 1973-10-01 1975-11-18 Gen Electric Variable resistor assembly
DE2823285A1 (de) * 1978-05-27 1979-11-29 Preh Elektro Feinmechanik Einstellbarer drehwiderstand
EP0153241A3 (en) * 1984-02-17 1986-05-14 Sangamo Weston, Inc. Small outline potentiometer
US5039974A (en) * 1990-03-19 1991-08-13 Ericsson Ge Mobile Communications Inc. Protective cap for rotatably-adjustable electronic components
US5113172A (en) * 1987-07-07 1992-05-12 Zahnradfabrik Friedrichshafen, Ag Angle of rotation potentiometer
US20080168798A1 (en) * 2000-12-28 2008-07-17 Kotliar Igor K Hypoxic aircraft fire prevention and suppression system with automatic emergency oxygen delivery system
US20080282818A1 (en) * 2007-05-17 2008-11-20 Charles Smith Sensors with nanoparticles
USD932107S1 (en) 2019-10-01 2021-09-28 Lincoln Global, Inc. Auto darkening filter for a welding helmet

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111640A (en) * 1962-06-15 1963-11-19 Edward W Dial Variable resistance device
US3581265A (en) * 1968-02-27 1971-05-25 Eugenio Falco Improvement in miniaturized potentiometers

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111640A (en) * 1962-06-15 1963-11-19 Edward W Dial Variable resistance device
US3581265A (en) * 1968-02-27 1971-05-25 Eugenio Falco Improvement in miniaturized potentiometers

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3876967A (en) * 1972-11-04 1975-04-08 Illinois Tool Works Variable resistor
US3921118A (en) * 1973-10-01 1975-11-18 Gen Electric Variable resistor assembly
DE2823285A1 (de) * 1978-05-27 1979-11-29 Preh Elektro Feinmechanik Einstellbarer drehwiderstand
US4310824A (en) * 1978-05-27 1982-01-12 Preh Elektrofeinmechanische Werke Jakob Preh Nachf. Gmbh & Co. Rotary variable resistor
EP0153241A3 (en) * 1984-02-17 1986-05-14 Sangamo Weston, Inc. Small outline potentiometer
US5113172A (en) * 1987-07-07 1992-05-12 Zahnradfabrik Friedrichshafen, Ag Angle of rotation potentiometer
US5039974A (en) * 1990-03-19 1991-08-13 Ericsson Ge Mobile Communications Inc. Protective cap for rotatably-adjustable electronic components
US20080168798A1 (en) * 2000-12-28 2008-07-17 Kotliar Igor K Hypoxic aircraft fire prevention and suppression system with automatic emergency oxygen delivery system
US20080282818A1 (en) * 2007-05-17 2008-11-20 Charles Smith Sensors with nanoparticles
USD932107S1 (en) 2019-10-01 2021-09-28 Lincoln Global, Inc. Auto darkening filter for a welding helmet

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Publication number Publication date
GB1380747A (en) 1975-01-15
DE7230513U (de) 1972-11-16
FR2151512A5 (enExample) 1973-04-20

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