US3601743A - Miniaturized single turn potentiometer with hermetically sealed rotor and substrate - Google Patents

Miniaturized single turn potentiometer with hermetically sealed rotor and substrate Download PDF

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Publication number
US3601743A
US3601743A US862888A US3601743DA US3601743A US 3601743 A US3601743 A US 3601743A US 862888 A US862888 A US 862888A US 3601743D A US3601743D A US 3601743DA US 3601743 A US3601743 A US 3601743A
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US
United States
Prior art keywords
rotor
substrate
resistance element
central
base member
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
US862888A
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English (en)
Inventor
Victor G Mathison
Robert M Hayflick
Bo Gustaf Fahlstrom
Charles W Yungblut
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Electra Midland Corp
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Electra Midland Corp
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Filing date
Publication date
Application filed by Electra Midland Corp filed Critical Electra Midland Corp
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Publication of US3601743A publication Critical patent/US3601743A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C10/00—Adjustable resistors
    • H01C10/30—Adjustable resistors the contact sliding along resistive element
    • H01C10/32—Adjustable resistors the contact sliding along resistive element the contact moving in an arcuate path

Definitions

  • Tolin Attorney-Wolfe, Hubbard, Leydig, Voit & Osann ABSTRACT: A miniaturized single turn potentiometer having a rotor and substrate and in which the rotor is of recessed configuration having peripheral contact .with the substrate and hermetically sealed with respect to the latter, with a contact spring seated in the recess for wiping the resistance element. Means are included for ensuring optimum contact pressure and to facilitate assembly so that proper phasing of the wiper with respect to the lead mounting is assured. Provision is made for substitution of basesfor different mounting styles with minimum change in the basic structure.
  • a potentiometer which may be usedalmost universally wherever variability of resistance with an appropriate rating of heat dissipation is required. Indeed, the construction is such that heavy overloads may be tolerated without running the risk of catastrophic failure.
  • FIG. 2 is a vertical section taken along the line 2-2 in FIG. 3;
  • FIG. 3 is a horizontal section looking along the line 33 in FIG. 2;
  • FIG. 4 is a bottom view of the potentiometer of FIG. 2;
  • FIG. 5 is an exploded view showing the parts which are as isolated to form the construction of the preceding figures;
  • FIG. 6 is a profile view of the contact spring
  • FIG. 7 is a vertical section taken through the rotor assembly looking along the line 77 in FIG. 8;-
  • FIG. 8 is a bottom view of the rotor assembly shown in FIG. 7;
  • FIG. 9 is a vertical section taken along the line 9-9 in FIG.
  • FIG. 10 is a section taken through the base and substrate along the line 10-10 in FIG. 4;
  • FIG. 11 is a fragmentary section through the base and substrate taken through the line 11 -11 in FIG. 4;
  • FIGS. 12, 13 and 14 are top, sectional, and bottom views respectively of a modified form of the invention.
  • FIGS. 1 to 4 a miniaturized single turn potentiometer 20 having terminal leads 21, 22, a central or wiper lead 23.
  • the potentiometer is adjusted by inserting a tool in a screwdriver slot 24 with the range of turning being limited by stops 25, 26.
  • a rotor 30 is provided which is of shallow cup shape having an axially extending flange 31 adjacent the periphery which encloses a central recess 32 and which further defines a peripheral shoulder 33. Positioned below the rotor is a wafer of substrate of disc shape and approximately the same diameter as the rotor 30. The ends of the lead wires, indicated at 21a, 22a, penetrate the substrate for making contact with the ends of the resistance element. The central lead 23 projects through the substrate to present an upraised tip 23a for engagement by the contact spring to be described.
  • a contact spring (see FIGS. 6-9 inclusive) having a generally flat body with an integral resilient wiper 51 formed of three parallel fingers which extend crosswise at one end. The fingers are rounded at the tips and sprung outwardly away from the plane of the body. Also formed integrally with the contact spring is a resilient leaf or tab '52 which is sprung outwardly for axial engagement of the tip 52a with the tip 23a of the central lead.
  • the spring body is formed with a nonsymmetrical profile and the recess in which it is received is of corresponding profile providing an interference fit.
  • the spring contact is made straight sided, having edges 53, 54 and the recess 32 is formed with internal walls 55, 56, respectively, which are straight sided and which are nonsymmetrically arranged with respect to the axis of the rotor (see FIGS. 8 and 9).
  • the contact is formed with points on at least one of its ends which dig into the rotor material, specifically, into the internal surface of the flange 31. As shown in FIGS. 6 and 8, the points, lying in the plane of the body, are indicated at 57, 58.
  • the opposite end of the spring contact member is preferably rounded to conform to the inner contour of the flange as shown at 59.
  • the wiper S1 is presprung outwardly from the plane of the member to project axially beyond the flange 31 by a distance l-ll. Since the flange seats on the substrate, and since the cermet resistance element is of constant thickness, maintaining a constant degree of projection H1 under production conditions ensures a wiper pressure falling within closely specified limits. Similarly, the central resilient leaf 52 is downwardly sprung so that it engages the central contact 23a which is raised above the surface of the substrate to achieve a high per unit pressure thereby reducing the casual resistance in the circuit to substantially zero.
  • any possi- 'O-ring 60 is provided adjacent the axial flange 31 and which bears against the shoulder surface 33 as well as against the land surface 46 on the substrate, the O-ring having a normal axial dimension which exceeds the length of the flange 31 by a predetermined amount indicated at H2 in FIG. 7, so that the O-ring is subjected to a predetermined amount of axial compression when the parts are assembled together.
  • the inner space 32 within the cup-shaped rotor is hermetically sealed against the entry of water vapor or air borne impurities.
  • the structure is to be distinguished from prior constructions in which epoxy or similar cement is utilized in a final sealing step and where the expansion of air within the confined space in- .cident to a high-temperature curing step may result in blow holes and other imperfections in the seal.
  • a base member is provided under the substrate, and the assembly consisting of the rotor, substrate and base, are all enclosed in a cup-shaped shell-type enclosure which may, for example, consist of thin metal, and which has an opening at its end to provide access to the rotor slot 24 for adjusting the rotor position limited by engagement of stops 25, 26.
  • a cup-shaped shell-type enclosure which may, for example, consist of thin metal, and which has an opening at its end to provide access to the rotor slot 24 for adjusting the rotor position limited by engagement of stops 25, 26.
  • an enclosure 70 of cup shape having bendable tabs along its lower edge indicated at 71-73 and having a central opening 74 for the purpose of clearing an embossment 65 which is integrally molded in the rotor and which contains the screwdriver slot 24.
  • the wafer of substrate 40 and the enclosure 70 are both uniquely keyed to the base 80.
  • the enclosure is keyed to the base by making the tabs 71-73 on the enclosure nonsymmetrical both in width and position and by forming the recesses 81-83 in the base of corresponding width and position to receive the inwardly bent tabs in a unique position. As will be noted in FIG.
  • the tab 71 received in recess 81, is substantially wider than the tabs 72, 73, ensuring that the enclosure and base can only be assembled in one way.
  • the substrate is formed with a pair of integral protuberances 85 which, when the parts are fitted together (see FIG. 11), are registered in correspondingly spaced recesses 86 in the base.
  • the base 80 is channeled out to define L- shaped paths, such as that indicated at 87 in FIG. 2, requiring each lead to adopt a zigzag configuration. Accordingly, each lead has a radially extending portion, indicated at 21b, 22b, 23b, respectively, at right angles to the line of pull.
  • preformed lead wires are inserted in the base 80, epoxy is applied, following which the substrate is seated on the base with the lead wires projecting through, and cemented to, the substrate as shown and with the protuberances 85 seated in alignment with recesses 86.
  • the keying together of the various elements with one way assembly between all of the parts ensures that the range of movement of the wiper will correspond precisely to the path of the resistance element on the substrate.
  • the prespringing of the wiper 51 and resilient leaf and the thickness of the O-ring 60 ensure that the wiper and O-ring will exert precisely the right amount of force against the surfaces which they engage notwithstanding the normally encountered tolerances in the molding of the rotor and notwithstanding the fact that the net-prespringing beyond the surface of the rotor flange 31, may be measured in terms of thousandths of an inch.
  • the rotor assemblies may be checked in a jig prior to final assembly to ensure the proper amount of projection of the resilient elements and O-ring with respect to the 1 presented face of the flange 31 used as reference.
  • the base b has a circular pedestal portion which directly underlies the substrate, just as in the preceding embodiment, but such pedestal is downwardly extended and provided with an integral side bracket which is separated from the pedestal by an arcuate groove 91 to accommodate the shell housing and which has through-openings 92, 93 for reception of the tabs 72b, 73b, which are bent over as shown (FIG. 14) to complete the assembly.
  • the construction of rotor, substrate and spring contact, as well as the construction of the housing, remain unchanged in this embodiment.
  • a miniaturized potentiometer comprising a rotor of shallow cup shape having an axial flange spaced inwardly from the periphery to define a central recess and an annular axially facing shoulder, a wafer of substrate of substantially the same diameter arranged below the rotor and contacting the lower surface of said axial flange, an interrupted circular resistance element on the substrate centered about a central contact, a contact spring secured to said rotor in said central recess and having a flat body integrally including a resilient wiper and a central resilient leaf engaging said resistance element, said resilient leaf extending from the plane thereof so that when the contact spring is seated in the recess the wiper extends slightly beyond the axial flange thereby to ensure engagement with the resistance element and central contact respectively when the-axial flange is ridingly seated on the substrate, a resilient O-ring encircling the axial flange and resiliently sandwiched between the shoulder on the rotor and the surface of the substrate for providing an her
  • a miniaturized potentiometer comprising a rotor of shallow cup shape having an axially extending flange extending about its periphery defining a central recess, an O-ring mounted adjacent the flange having a normal diameter greater than the height of the flange, a wafer of substrate arranged below the rotor having an interrupted circular resistance element surrounded by a land engaging the lower surface of said axial flange and said O-ring, a contact spring secured to said rotor in said central recess and having a flat body integrally including a resilient wiper and a central resilient leaf engaging said resistance element, said resilient leaf extending from the plane thereof so that when the contact spring is seated in the recess the wiper extends slightly beyond the axial flange thereby to ensure application of predetermined pressure against the resistance element when the flange is in riding engagement with the substrate, a central lead penetrating the substrate for making pivoting contact with the resilient leaf, terminal leads penetrating the substrate for making contact with the ends
  • a miniaturized potentiometer comprising a rotor of shallow cup shape having an axial flange spaced inwardly from the periphery to define a central recess and an annular axially facing shoulder, a wafer of substrate of substantially the same diameter arranged below the rotor and contacting the lower surface of said axial flange, an interrupted circular resistance element on the substrate centered about a central contact, a contact spring secured to said rotor in said central recess and having a flat body integrally including a resilient wiper and a central resilient leaf engaging said resistance element, an O-ring surrounding the flange and sandwiched between the substrate and shoulder thereby to provide a moisture and dustproof seal for the resistance element and contact member, a base member underlying said substrate and supportingly engaging the lower surface of said substrate, an enclosing shell surrounding the rotor, substrate and base member while permitting access to the rotor for angular adjustment of the latter, said enclosing shell pressing against the upper surface of said
  • a miniaturized potentiometer comprising a rotor of shallow cup shape having an axial flange spaced inwardly from the periphery enclosing a central recess, a wafer of substrate of substantially the same diameter arranged below the rotor and contacting the lower surface of said axial flange, an interrupted circular resistance element on the substrate centered about a central contact, a contact spring secured to said rotor in said central recess and having a flat body integrally including a resilient wiper and a central resilient leaf engaging said resistance element, an O-ring ad- 5 jacent the flange for contacting the substrate, a base member underlying said substrate and supportingly engaging the lower surface of said substrate, an enclosing shell surrounding the rotor, substrate and base member and having a central opening for permitting access to the rotor for angular adjustment of the latter, said enclosing shell pressing against the upper surface of said rotor and the lower surface of said base member to hold the rotor
  • a miniaturized potentiometer comprising a rotor of shallow cup shape having a peripheral flange enclosing a central recess, and O-ring arranged adjacent the flange, a substrate having an interrupted circular resistance element surrounded by a land engaging the lower surface of said flange and said O-ring, a contact spring secured to said rotor in said central recess and having a flat body integrally ineluding a resilient wiper and a central resilient leaf extending from the plane thereof and engaging said resistance element, leads penetrating the substrate for making connection to the ends of the resistance element, a central lead penetrating the substrate and projecting beyond the surface thereof for making contact with the resilient leaf on the contact spring, said leads being sealed to the substrate, the rotor having an adjusting slot formed in its upper surface, a base member underlying said substrate and supportingly engaging the lower surface of said substrate, means including a shell for enclosing and clamping together the rotor, substrate and base member and including

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Adjustable Resistors (AREA)
  • Exhaust Gas After Treatment (AREA)
US862888A 1969-10-01 1969-10-01 Miniaturized single turn potentiometer with hermetically sealed rotor and substrate Expired - Lifetime US3601743A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US86288869A 1969-10-01 1969-10-01

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US3601743A true US3601743A (en) 1971-08-24

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US862888A Expired - Lifetime US3601743A (en) 1969-10-01 1969-10-01 Miniaturized single turn potentiometer with hermetically sealed rotor and substrate

Country Status (7)

Country Link
US (1) US3601743A (de)
JP (1) JPS4916144B1 (de)
BE (1) BE756846A (de)
DE (2) DE2047568C3 (de)
FR (1) FR2068245A5 (de)
GB (1) GB1307129A (de)
NL (1) NL7014312A (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5093232U (de) * 1973-12-27 1975-08-06
JPS552176U (de) * 1979-03-22 1980-01-09
US4295119A (en) * 1979-03-12 1981-10-13 Alps Electric Co., Ltd. Rotary variable resistor
US4329676A (en) * 1980-01-10 1982-05-11 Resistance Technology, Inc. Potentiometer
DE3609655A1 (de) * 1985-03-22 1986-09-25 Copal Electronics Co., Ltd., Tokio/Tokyo Potentiometer
US4812804A (en) * 1986-09-09 1989-03-14 Ken Hayashibara Controller for electric devices directed to use in bath
US4868536A (en) * 1986-08-31 1989-09-19 Ken Hayashibara Output controller for electrotherapeutic device directed to use in a bath
US5043695A (en) * 1990-06-15 1991-08-27 Bourns, Inc. Housing assembly for miniature electronic device
US5095298A (en) * 1990-12-13 1992-03-10 Bourns, Inc. Surface mount variable resistor with insert-molded slider
US5721526A (en) * 1995-07-20 1998-02-24 Hokuriku Electric Industry Co., Ltd. Compact high-voltage variable resistor
US5726625A (en) * 1994-12-28 1998-03-10 Hokuriku Electric Industry Co., Ltd. High-voltage variable resistor
US5886616A (en) * 1996-06-27 1999-03-23 Hokuriku Electric Industry Co., Ltd. High-voltage variable resistor unit
US6380841B2 (en) * 2000-01-04 2002-04-30 Murata Manufacturing Co., Ltd. Variable resistor
US6396385B1 (en) * 1999-07-30 2002-05-28 Murata Manufacturing Co., Ltd. Variable resistor
US6744347B2 (en) * 2001-01-04 2004-06-01 Murata Manufacturing Co., Ltd. Variable resistor

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5063046U (de) * 1973-10-09 1975-06-09
JPS59187102U (ja) * 1983-05-31 1984-12-12 アルプス電気株式会社 回転形電気部品の摺動子
DE3344445A1 (de) * 1983-12-08 1985-06-20 Siemens AG, 1000 Berlin und 8000 München Potentiometer
JPH0630290B2 (ja) * 1987-05-15 1994-04-20 株式会社村田製作所 可変抵抗器
JP2603105B2 (ja) * 1988-06-06 1997-04-23 株式会社村田製作所 可変抵抗器とその製造方法
DE3936679C2 (de) * 1988-11-05 1994-02-17 Murata Manufacturing Co Regelwiderstand
DE202014103992U1 (de) 2014-08-26 2014-10-22 Contelec Ag Positionssensor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3222467A (en) * 1963-06-24 1965-12-07 Gen Motors Corp Cam centered electric switch with moisture-proof sealing means
US3237140A (en) * 1963-05-20 1966-02-22 Cts Corp Variable resistance control
US3309471A (en) * 1966-05-23 1967-03-14 Appliance Mfg Co Inc Rotary switch contact structure with improved washer fastening means
US3350673A (en) * 1966-06-10 1967-10-31 Allen Bradley Co Adjustable electronic component
US3512113A (en) * 1968-06-28 1970-05-12 Weston Instruments Inc Miniaturized rotary potentiometers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3237140A (en) * 1963-05-20 1966-02-22 Cts Corp Variable resistance control
US3222467A (en) * 1963-06-24 1965-12-07 Gen Motors Corp Cam centered electric switch with moisture-proof sealing means
US3309471A (en) * 1966-05-23 1967-03-14 Appliance Mfg Co Inc Rotary switch contact structure with improved washer fastening means
US3350673A (en) * 1966-06-10 1967-10-31 Allen Bradley Co Adjustable electronic component
US3512113A (en) * 1968-06-28 1970-05-12 Weston Instruments Inc Miniaturized rotary potentiometers

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5093232U (de) * 1973-12-27 1975-08-06
US4295119A (en) * 1979-03-12 1981-10-13 Alps Electric Co., Ltd. Rotary variable resistor
JPS552176U (de) * 1979-03-22 1980-01-09
JPS5918644Y2 (ja) * 1979-03-22 1984-05-30 コパル電子株式会社 可変抵抗器のピン端子
US4329676A (en) * 1980-01-10 1982-05-11 Resistance Technology, Inc. Potentiometer
DE3609655A1 (de) * 1985-03-22 1986-09-25 Copal Electronics Co., Ltd., Tokio/Tokyo Potentiometer
US4868536A (en) * 1986-08-31 1989-09-19 Ken Hayashibara Output controller for electrotherapeutic device directed to use in a bath
US4812804A (en) * 1986-09-09 1989-03-14 Ken Hayashibara Controller for electric devices directed to use in bath
US5043695A (en) * 1990-06-15 1991-08-27 Bourns, Inc. Housing assembly for miniature electronic device
US5095298A (en) * 1990-12-13 1992-03-10 Bourns, Inc. Surface mount variable resistor with insert-molded slider
US5726625A (en) * 1994-12-28 1998-03-10 Hokuriku Electric Industry Co., Ltd. High-voltage variable resistor
US5933070A (en) * 1994-12-28 1999-08-03 Hokuriku Electric Industry Co., Ltd. High-voltage variable resistor
US5721526A (en) * 1995-07-20 1998-02-24 Hokuriku Electric Industry Co., Ltd. Compact high-voltage variable resistor
US5886616A (en) * 1996-06-27 1999-03-23 Hokuriku Electric Industry Co., Ltd. High-voltage variable resistor unit
US6396385B1 (en) * 1999-07-30 2002-05-28 Murata Manufacturing Co., Ltd. Variable resistor
US6380841B2 (en) * 2000-01-04 2002-04-30 Murata Manufacturing Co., Ltd. Variable resistor
US6744347B2 (en) * 2001-01-04 2004-06-01 Murata Manufacturing Co., Ltd. Variable resistor

Also Published As

Publication number Publication date
DE2047568B2 (de) 1980-06-12
JPS4916144B1 (de) 1974-04-19
BE756846A (fr) 1971-03-01
DE2047568C3 (de) 1981-02-19
GB1307129A (en) 1973-02-14
DE7035855U (de) 1971-01-14
FR2068245A5 (de) 1971-08-20
DE2047568A1 (de) 1971-04-08
NL7014312A (de) 1971-04-05

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