US3579169A - Variable resistor for dual operation - Google Patents

Variable resistor for dual operation Download PDF

Info

Publication number
US3579169A
US3579169A US796686A US3579169DA US3579169A US 3579169 A US3579169 A US 3579169A US 796686 A US796686 A US 796686A US 3579169D A US3579169D A US 3579169DA US 3579169 A US3579169 A US 3579169A
Authority
US
United States
Prior art keywords
brush
resistance
track
tracks
apex
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
US796686A
Other languages
English (en)
Inventor
Clarence R Dickinson
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.)
Allen Bradley Co LLC
Original Assignee
Allen Bradley Co LLC
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 Allen Bradley Co LLC filed Critical Allen Bradley Co LLC
Application granted granted Critical
Publication of US3579169A publication Critical patent/US3579169A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01C10/34—Adjustable resistors the contact sliding along resistive element the contact moving in an arcuate path the contact or the associated conducting structure riding on collector formed as a ring or portion thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C10/00—Adjustable resistors
    • H01C10/16—Adjustable resistors including plural resistive elements
    • H01C10/20—Contact structure or movable resistive elements being ganged

Definitions

  • ABSTRACT A variable resistor providing an integral as- U.S.Cl 338/170, sembly for dual operation comprising a i f arcuate 338/132 338/164! 338/167, 338/174 338/202 sistance track elements in axially spaced, face-to-face relall'llt. tion hi and having interposed therebetween a single insulat.
  • Field of Search 338/ 128, ing rotor or b h can'ier including oppositely facing cavities, 130, 132, 162, 164, 166, 167, 170, 171, 174, 184, each cavity being recessed relative to a central plane and 202, 230 adapted to individually receive conducting brush members.
  • Biasing springs are provided for maintaining the brush mem- References cued bers in electrical contact with the respective resistance ele- UNITED STATES PATENTS ments, as well as individual terminal assemblies for each of the 2,111,810 3/1958 Schellenger 201/55 resistance elements.
  • the present invention relates to mechanically variable resistors having movable contacts electrically adjustable over a length of resistance element, and in particular to a variable resistor wherein there is a pair of such resistance elements in axially spaced, facing relationship and including respective movable contacts for each of the elements actuated by a single rotor, and in which all of the components are enclosed in a single, housing.
  • the present invention in its preferred embodiment, adapts certain of the features of the Variable Resistance Device disclosed in US. Pat. No. 2,839,642 granted to the present inventor jointly with Bernard F. Tellkamp and assigned to the same assignee as the present invention. That is, the embodiment may utilize integrally molded resistor elements such as those set forth in the US. Pat. Nos. 2,269,136 and 2,514,682 to Tellkamp. However, it is contemplated that the construction of tee resistance elements may take other forms such as conventional cermet or thick film resistance tracks, as well as other resistance tracks well known in the art.
  • the resistance elements each provide an arcuate track which may be of constant resistance throughout its length or variable, as desired, and in the case of otentiometers, a centrally disposed collector track of conducting, low-resistance material.
  • the resistance elements are retained in axially spaced, face-to-face relationship by means of a tubular enclosure or casing.
  • An operating shaft protrudes through a central aperture of one of the resistance elements and has attached to its internal end portion an insulating rotor elementincluding two oppositely disposed cavities recessed inwardly relative to a central plane dividing the rotor perpendicularly of its axis.
  • each of the cavities there is located a conducting brush which is rotatable with the rotor about an axis substantially concentric with the respective resistance tracks and having collector engaging portions in sliding contact with the collector track and a resistance engaging portion in sliding contact with the resistance track.
  • Relatively flat spring elements are seated in the respective cavities to bias the brushes outwardly of the cavities and towards their respective resistance elements.
  • variable resistor of diminutive size which includes among its various features the provision of well proven and commercially accepted resistance elements and brush constructions and which combine all of these features in the device to provide a dual functioning, variable resistor enclosed within a single housing to thereby reduce both its radial and axial length when compared to conventional tandem operated variable resistors.
  • FIG. 1 is a longitudinal view, partially in section, of a variable resistor in the form of a potentiometer incorporating the teachings of the present invention
  • FIG. 2 is a cross-sectional view taken along lines 2-2 of FIG. 1 and illustrating, more particularly, a construction of the rotor or brush carrier;
  • FIG. 3 is a cross-sectional view taken along lines 3-3 of FIG. I, and illustrates the configuration of the resistance track and collector track as used in the dual resistance elements;
  • FIG. 4 is an enlarged fragmentary view of another embodiment of the brush construction.
  • FIGS. l3 there is shown a resistance element in the form of a molded base 10 of insulating material.
  • the base 10 provides a surface 11 preferably of circular configuration.
  • the configuration of the resistance and collector tracks of the surface 11 is similar to the interior surface 12 of an axially spaced resistance element 13, except for a rotative positioning relative to the longitudinal plane of the device for purposes hereinafter described. Attention is directed to'FlG. 3 which more clearly shows the configuration of the surface 12 of the element 13.
  • the tracks 14,15 each comprise a shallow layer of conducting material in the form of distributed carbon-black particles dispersed within the molded material of the respective base 10 and element 13 to have become an integral portion thereof upon molding.
  • Substantially concentric with the resistance tracks 14, 15 are respective collector tracks 16 and 17, also exposed fiush with the respective faces 11 and 12.
  • the tracks 16, 17 cover a circular area at the center of the respective faces 11 and 12 and, like the tracks 14, 15 are formed of a plurality of conducting particles molded integrally with the respective base 10 and element 13 in a shallow layer near the surface.
  • the particles comprising the collector tracks 16, 17 are more densely distributed only rather than a potentiometer, in the form of thick film or cermet surfaces as is well known in the art.
  • a set of threeterminal leads 20 are embedded within the base 10 at the time of molding and there disposed with the embedded end of one in electrical contact with the collector track 16 and the embedded ends of the others in contact with the end portions of the resistance track i 14.
  • the terminals 20 are shown in longitudinal projection
  • the terminals 21 of the element '13 are molded in ⁇ place in similar manner to terminals 20, and project downwardly relative to FIG. 1. Should it be desired to provide the aforementioned means for including downwardly projecting terminals 20, the setsof terminals 20,21 will be chosen dimensionally to fit into known circuit board constructions.
  • Both the molded base 10 and the resistance element 13 also have embedded therein metallic heat extracting and housing anchoring inserts 22 and 23, preferably composed of a :metal having high heat conductivity.
  • the inserts are more clearly shown and described in detail in the Dickinson et al. US. Pat. No. 2,839,642. They generally take the form of an interrupted cylinder with a plurality of perforations through which the material of the-base 10 and theelement 13 may flow, upon molding, to rigidly secure the inserts 22, 23.
  • Each of the in serts 22, 23 with its respective forward edge 24, 25 behind, spaced from but very, near the respective resistance tracks 14, 15, as shown in FIG. 1, to readily receive heat released within the resistance tracks l4, 15 and to conduct the same to the exterior of the'base 10 and resistance element 13.
  • the base 10 and resistance element 13 are retained in axially spaced relationship by means of a housing or casing-26 which is preferably of a metallic heat-conducting material.
  • a housing or casing-26 which is preferably of a metallic heat-conducting material.
  • the casing'26' is provided'with a set of ears (not shown) which act to retain a threaded bushing 30 having a circular base 31 resting against the resistance elenient 13.v
  • the free ends of the aforementionedears are bent over the bushing base 31 to secure the bushing 30 in position.
  • Extending through the bushing 30 is an operating shaft-32 having a reduced cross section33 and a'knurled end 34 withirijthe casing '26.
  • the knurled end 34 and the reduced portion 33 are embedded within a'molded contact carrier or rotor 35 composed of an insulating material.
  • the rotor is provided with a projecting molded portion 39 which acts to insulate the shaft 32 -from the collector ring 17 in addition tojproviding a "bearingsurface for thero'tor 35.
  • the bushing 30 is recessed at 36 to receive an -O-rin'g gasket 37 which is compressed between the interior circular wall of the recessed cavity 36 and the shaft 32 to provide a seal.
  • the brush carrier or rotor 35 is slotted at 38 for purposes of assembly in order to clear the inwardly folded portion 27 of the casing.
  • the rotor'35 is molded'to proyide a projection which will engage either side of the portion 2 7 for purposes of limiting rotation thereof.
  • each of the brushes has a substantially identical configuration, the rear- I ward side of brush 43 and the forward side of brush 42 being shown in the cross-sectional view of FIG. 2.
  • the brush carrier 35 is provided with an arcuate protruding portion 46 which acts as a stop for the rotor 35 on any endward, axial thrust being placed upon the shaft 32 during adjustment. That is, the rotor 35 will in no way touch the resistance'track 15 or the collector track 17 as the *protruding'portion 46 is disposed to rest against the inner 'face 11 of the base 10 intermediate the said tracksl5 and 17.
  • Each of the brushes 42,43 are of general 'triangular'configuration to be respectively seated in the generally triangular configured recesses 40 and 4-1 of the rotor 35, respectively.
  • each of the brushes 4 2,43 are provided with three 'co ntacttoes47, 48 and 49.
  • the two radially inwardly disposed toes 48, 49 rest upon and electrically engage the respective collector tracks 10 and 17 of the baselfl'and the resistance element 13. whereas the outwardly positioned toe 47'rides upon and electrically engages the resistance-tracks 14 and 15.
  • the triangular disposition and spacingtofthe toes 47, 48 and 49' also provides stability for the respective brushes 42, 43.
  • the springs 44 are disposed in laterally projecting recessed portions of the cavities 40 and 41.
  • the laterally projecting recesses are formed with abutments at their extremities 50 to receive the ends of the respective springs 44,45.
  • the intermediate portion'of each of the springs 44, 45 bears againstthe angled back surface 51 of the respective brushes 42,43 and is bowed to'provide necessary contact pressure between-the brush toes 47 and the exposed surface areas of the tracks 14, 1'5 and 16, 17.
  • the force exerted by the springs 44, 45 against the angled back surface'SI' divides into two components,-one biasing the respective brush 42, 43 towards the respective faces 11 and 12, and the other force component biasing the respective brush in adirection towards the forward surface defining the toe 47.
  • the latter-component acts to retain the brush'in its cavity, which is especially helpful during assembly of the device.
  • the use of a plurality of springs 44, 45 permitscontacting engagement-with the angled backsurface 51 of the brush'to provide a spring characteristic similar to that of a flat spring.
  • This arrangement provides desired contact pressure between the toe 47 and the respective resistor track 14, 15. However, such arrangement also tends to wedge the apex forming the outer surface of the toe 47 of the triangular brush against the mating surface of the triangular recess of the rotor 35.
  • the surface of the recess engaging the toe 47 is preferably formed as shown in FIG. 4. That is, the apex is further defined by the planar surface portions 52iand 53, which lie in angular planes intersecting at the-terminus of the apex. This provides a two point" contact for the rounded toe 47.
  • the brush 43 (shown in FIG. 4) and the brush 42 will then be assured freedom of movement in the recess 41 of the rotor 35 even under bias of the respective springs 45,-44.
  • a variable resistance apparatus comprising: a housing; J I a pair of spaced-apart, stationary insulating substrate element supported by said housing, at least one of which includes'a shaft-receivingaperture; an arcuate resistance track and a conducting collector track supported by each of said substrate elements and in respective facing relationship;
  • a rotatable shaft received in the apertured substrate element and extending inwardly of said housing;
  • said contact brush carrier containing a pair of reentrant brush-receiving cavities on opposite sides thereof and disposed'angularly relative to one another, the operi ends of said cavities facing respective resistance tracks and collector tracks supported by the respective substrate elements, the said reentrant cavities of said brush carrier each having a depth exceeding one-half the axial length of said brush carrier;
  • biasing means at opposite sides of said contact carrier disposed in said respective cavities intermediate a respective inner end of said cavities and its respective brush, thereby biasing said brush into electrical bridging engagement with said resistance track and said conducting collector track supported by the respective substrate elements;
  • variable resistance apparatus of claim 1 wherein said respective brushes are of triangular configuration and include three protruding toes each being located at the respective apices of each of said brushes, one of said toes being in sliding electrical contact with said arcuate resistance track and the remaining toes being in sliding electrical contact with said collector track.
  • each of the brush-receiving cavities are triangularly shaped and disposed with on apex positioned for rotational alignment with its respective arcuate resistance track and said one apex being further configured at its terminus to define planar wall surfaces lying in angular intersecting planes, said wall surfaces being normal to said respective resistance track, and said respective brushes being triangularly shaped and seated in a respective cavity with one apex being arcuately configured and in linear engagement with each of the respective said planar wall surfaces of said one apex of said cavity.
  • variable resistance apparatus of claim 1, wherein the distal end surface of the shaft-supported brush carrier includes a protruding portion spaced from said arcuate resistance track to prevent the said end surface from wiping against said track during rotation of said shaft.
  • variable resistance apparatus wherein the inner back surface of each of the respective brushes is angularly disposed relative to the plane intersecting the end of said brushes in electrically bridging engagement with said tracks, and wherein the biasing means comprises an elongated spring disposed transversely of and pressing against said angularly disposed back surface to provide a resultant force acting to concurrently force the respective brush in a direction into engagement with its respective resistance track and to force said arcuately formed apex of said brush into said linear engagement with said planar wall surfaces of said cavity.
  • variable resistance apparatus comprising:
  • a stationary insulating substrate element supported by said housing and including an interiorly facing surface supporting an arcuate resistance track and a conducting collector track;
  • a rotatable shaft extending inwardly of said housing and supporting at its inner end a contact brush carrier;
  • a conducting brush seated in said cavity and having an exposed surface in slidably electrically bridging engagement with said tracks, said brush being triangularly shaped with one apex being arcuately configured and in linear engagement with each of the respective planar wall surfaces of said one apex of said cavity;
  • biasing means disposed in said cavity intermediate the inner end of said cavity and said brush, to thereby bias said brush into electrical bridging engagement with said tracks.
  • variable resistance apparatus the inner back surface of said'brush being angularly disposed relative to the plane intersectingthe end of said brush in electrically bridging engagement with said tracks
  • said biasing means comprises an elongated spring disposed transversely of and pressing against said angularly disposed back surface of said brush to provide a resultant force acting to concurrently force the brush in a direction towards engagement with said tracks and to force said arcuately formed apex of said brush into said linear engagement with said planar wall surface of said cavity.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Adjustable Resistors (AREA)
US796686A 1969-02-05 1969-02-05 Variable resistor for dual operation Expired - Lifetime US3579169A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US79668669A 1969-02-05 1969-02-05

Publications (1)

Publication Number Publication Date
US3579169A true US3579169A (en) 1971-05-18

Family

ID=25168791

Family Applications (1)

Application Number Title Priority Date Filing Date
US796686A Expired - Lifetime US3579169A (en) 1969-02-05 1969-02-05 Variable resistor for dual operation

Country Status (2)

Country Link
US (1) US3579169A (enrdf_load_stackoverflow)
GB (1) GB1296196A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760323A (en) * 1972-09-25 1973-09-18 Continental Wirt Electronic Insulated wire wound resistor
US3932831A (en) * 1974-06-25 1976-01-13 Spectrol Electronics Corporation Variable resistance device
US4310824A (en) * 1978-05-27 1982-01-12 Preh Elektrofeinmechanische Werke Jakob Preh Nachf. Gmbh & Co. Rotary variable resistor
US5745025A (en) * 1995-02-03 1998-04-28 Preh-Werke Gmbh & Co. Kg Snap-engaging apparatus for a rotable component
US5986421A (en) * 1997-08-14 1999-11-16 Koito Manufacturing Co., Ltd. Safety device for power window
US6040757A (en) * 1998-03-03 2000-03-21 Murata Manufacturing Co., Ltd. Variable resistor
EP0999561A1 (en) * 1998-11-02 2000-05-10 Alps Electric Co., Ltd. Rotary variable resistor
US20050184850A1 (en) * 2004-02-24 2005-08-25 Alps Electric Co., Ltd. Rotating type variable resistor
US7167075B1 (en) * 2004-12-03 2007-01-23 Jefferson Science Associates, Llc Dual design resistor for high voltage conditioning and transmission lines
US20170133132A1 (en) * 2014-09-11 2017-05-11 Emhiser Research Limited Multi-resolution potentiometer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2111810A (en) * 1933-05-26 1938-03-22 Chicago Telephone Supply Co Rheostat
US2506491A (en) * 1948-11-08 1950-05-02 Phillips Petroleum Co Volume control
US2514682A (en) * 1948-04-09 1950-07-11 Allen Bradley Co Variable resistor apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2111810A (en) * 1933-05-26 1938-03-22 Chicago Telephone Supply Co Rheostat
US2514682A (en) * 1948-04-09 1950-07-11 Allen Bradley Co Variable resistor apparatus
US2506491A (en) * 1948-11-08 1950-05-02 Phillips Petroleum Co Volume control

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760323A (en) * 1972-09-25 1973-09-18 Continental Wirt Electronic Insulated wire wound resistor
US3932831A (en) * 1974-06-25 1976-01-13 Spectrol Electronics Corporation Variable resistance device
US4310824A (en) * 1978-05-27 1982-01-12 Preh Elektrofeinmechanische Werke Jakob Preh Nachf. Gmbh & Co. Rotary variable resistor
US5745025A (en) * 1995-02-03 1998-04-28 Preh-Werke Gmbh & Co. Kg Snap-engaging apparatus for a rotable component
US5986421A (en) * 1997-08-14 1999-11-16 Koito Manufacturing Co., Ltd. Safety device for power window
US6040757A (en) * 1998-03-03 2000-03-21 Murata Manufacturing Co., Ltd. Variable resistor
EP0999561A1 (en) * 1998-11-02 2000-05-10 Alps Electric Co., Ltd. Rotary variable resistor
US6275140B1 (en) 1998-11-02 2001-08-14 Alps Electric Co., Ltd. Rotary variable resistor
US20050184850A1 (en) * 2004-02-24 2005-08-25 Alps Electric Co., Ltd. Rotating type variable resistor
US7369033B2 (en) * 2004-02-24 2008-05-06 Alps Electric Co., Ltd. Rotating type variable resistor
CN100458985C (zh) * 2004-02-24 2009-02-04 阿尔卑斯电气株式会社 旋转型可变电阻器
US7167075B1 (en) * 2004-12-03 2007-01-23 Jefferson Science Associates, Llc Dual design resistor for high voltage conditioning and transmission lines
US20170133132A1 (en) * 2014-09-11 2017-05-11 Emhiser Research Limited Multi-resolution potentiometer
US9741478B2 (en) * 2014-09-11 2017-08-22 Emhiser Research Limited Multi-resolution potentiometer

Also Published As

Publication number Publication date
GB1296196A (enrdf_load_stackoverflow) 1972-11-15

Similar Documents

Publication Publication Date Title
US2632830A (en) Indexed control
US3579169A (en) Variable resistor for dual operation
JPH0461577B2 (enrdf_load_stackoverflow)
US3760342A (en) Terminal construction for electrical conductors
US3657688A (en) Compact variable resistor with rotary resistance element
US4527147A (en) High voltage variable resistor with improved central slider contact construction
US2839642A (en) Variable resistance device
US3500282A (en) Panel mounted,variably adjusted electrical component
US4114131A (en) Variable resistor
US4302659A (en) Ceramic heater-element to be used for cigarette-lighters
US4109230A (en) Compact electrical control
US4047146A (en) Variable resistor assembly
US3102990A (en) Variable resistor contact
US3387247A (en) Housing and base construction for variable resistance device
US2952825A (en) Electrical resistor
US3518604A (en) Electrical component
US3363212A (en) Variable resistance component
US3602861A (en) Hybrid element variable resistor
US2939097A (en) Variable resistance device
US2916717A (en) Variable resistor
US3320571A (en) Resistive attenuator
US4060788A (en) Potentiometer
US2989718A (en) Electrical resistor
US2852644A (en) Potentiometers
KR980005075A (ko) 고압용 가변 저항기