[go: up one dir, main page]

US3497855A - Helical coil variable potentiometer and method of constructing same - Google Patents

Helical coil variable potentiometer and method of constructing same Download PDF

Info

Publication number
US3497855A
US3497855A US674043A US3497855DA US3497855A US 3497855 A US3497855 A US 3497855A US 674043 A US674043 A US 674043A US 3497855D A US3497855D A US 3497855DA US 3497855 A US3497855 A US 3497855A
Authority
US
United States
Prior art keywords
coil
potentiometer
housing
helical
slider
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
US674043A
Other languages
English (en)
Inventor
Guenter W Mueller
Hans Habereder
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.)
Systron Donner Corp
Original Assignee
Duncan Electronics 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 Duncan Electronics Inc filed Critical Duncan Electronics Inc
Application granted granted Critical
Publication of US3497855A publication Critical patent/US3497855A/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
    • H01C10/24—Adjustable resistors the contact moving along turns of a helical resistive element, or vica versa
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C10/00—Adjustable resistors
    • H01C10/30—Adjustable resistors the contact sliding along resistive element
    • H01C10/301—Adjustable resistors the contact sliding along resistive element consisting of a wire wound resistor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
    • H01C17/04—Apparatus or processes specially adapted for manufacturing resistors adapted for winding the resistive element

Definitions

  • This invention relates generally to variable electrical potentiometers of the helical coil type with a movable electrical contact or brush that rubs on said coil from the inside thereof, and traverses said coil from end to end. More particularly, the invention is directed to meth ods of constructing such potentiometers and to new constructional features and combinations facilitating the manufacture of a superior potentiometer of this type in a miniaturized size, and at comparatively low cost.
  • the conventional helical coil potentiometer has a hollow insulation cylinder formed interiorly with a helical groove, in which is positioned a helical coil of resistance wire.
  • a brush on a slider inside the coil contacts the inner surface of this coil, while the slider meshes With the helical groove.
  • the slider slides along a rotor which is rotated by an axial shaft, and accordingly both rotate and advance axially in such a manner that the brush which it carries slides along the helical coil. Potentiometers of this type have been used successfully in large numbers.
  • the present invention involves the concept of splitting the interiorly grooved housing cylinder into two (or more) parts, and assembling the parts about a pre-formed resistance wire coil.
  • the housing has cylinder ends, and the housing parts are held in assembly about the coil by means of two end rings fitted tightly over these ends. These end rings are actually made to serve three functions: first, to hold the split housing together in assembly with the coil; second, to furnish integral external electrical connection tabs; and, third, to act as a heat sink, guarding against undue heating of and damage to the parent material of the housing during soldering of external electrical connections to the ring tabs.
  • FIG. 1 is a perspective view, to approximately full scale, of a potentiometer in accordance with the invention
  • FIG. 2 is a longitudinal medial section taken on line 2-2 of FIG. 1;
  • FIG. 3 is a transverse section taken on line 33 of FIG. 2;
  • FIG. 3a is a detail section on line 3a-3a of FIG. 3;
  • FIG. 3b is a section on line 3b3b of FIG. 3a;
  • FIG. 4 is an enlarged fragmentary detail taken from FIG. 2;
  • FIG. 5 is a detail section taken on line 5-5 of FIG. 1;
  • FIG. 6 is a view similar to FIG. 5 but showing the parts after finishing;
  • FIG. 7 is a transverse section taken in accordance with line 77 of FIG. 2;
  • FIG. 8 is a section taken in accordance with line 8-8 of FIG. 2;
  • FIG. 8a is a section on line 8a8a of FIG. 2;
  • FIG. 9 is a perspective view of an electrical brush
  • FIG. 10 is a perspective view of a slip ring
  • FIG. 11 is an exploded view of the potentiometer.
  • the potentiometer of the invention may be constructed in various sizes, but that principally in present contemplation is as shown approximately to full scale in FIG. 1.
  • the potentiometer has a housing 15 comprised of a cylinder or barrel 16, and two end caps 17 and 18 fitted to opposite ends of the latter. These body parts are preferably molded from a suitable thermoplastic material, such as a plastic marketed by Union Carbide Corporation, and identified as polysulfone, type P1710.
  • the barrel 15 has molded therein the helical groove 20, and is split diametrically into two halves 20a and 20b. These halves have mating ribs and grooves 21 and 22, respectively, which aid in assembly. Thus when the two halves are in assembly, they form the continuous helical groove 20 adapted to snugly receive a resistance wire coil 24, which is preformed to fit precisely in the groove 20, in the very bottom thereof, as shown.
  • the groove 20 is defined by a helical rib 26, and there is sufficient space in the groove 20, inside the coil 24, to receive helical thread elements 29 on opposite ends of a slider 30.
  • the slider 30 has an aperture 32 through it which is in the general cross-sectional shape of a somewhat flattened hexagon; and received in this aperture, with a relatively close but free sliding fit, is an elongated rotor 34 which is tightly mounted on the end of an axially disposed rotatable potentiometer adjustment shaft 36.
  • the slider and rotor are preferably molded from the same material as the housing sleeve.
  • the housing cylinder or barrel 16 formed by the two housing halves 20a and 20b has, projecting from each end, on an outside diameter which is somewhat smaller than the barrel, an annular end ring or projection 38, and on each of these is fitted a flat, electrically conductive holding and electric terminal ring 40', shouldered tight against the barrel shoulder 41.
  • the wire coil is first preformed to its final shape or form, then nested into the half-helical groove in one of the housing parts 20a, 20b, and the other housing part then fitted over the first, the coil being at this time nicely and snugly received in the half-helical groove in said other housing part.
  • the two housing parts are then moved together until they meet along the plane of their split, with the coil worked down in the helical groove, and the rings 40 are then installed, holding the parts described in tight assembly.
  • Each ring 40' has a radially projecting electrical terminal tab 45, and inside and in line therewith, the barrel end ring part or projection 38 is notched, as at 46, and to one side of this notch is apertured through the first turn of the helical rib 26, as at 47, so as to expose the resistance wire of the coil at a point near its end, in the last turn of the rib.
  • a short length of metallic ribbon 48 is then spot welded to the ring 40, in line with the tab 45, and is spot welded also to the resistance wire coil where exposed by the aperture 47. The two ends of the coil are thus electrically connected to the two terminal tabs 45.
  • a feature of the invention is that in soldering external electrical connections to the tabs 45, the heat from the operation flows into the rings 40, which are of enough bulk to serve adequately as heat sinks, preventing temperature rises such as would otherwise tend to damage the thermoplastic material of the potentiometer housing. This feature is deemed to be of material importance, in that it solves an otherwise difficult problem.
  • the aforementioned end caps 17 and 18 of housing comprise end walls 50 and 51, and annular flanges 5.2 and 53, respectively.
  • the annular flanges 52 and 53 are shaped to form depressed interior annular seats 60, which engage the aforementioned metal rings 40 mounted on the end ring portions 38 of the barrel, these flanges having a slip-fit over the metal holding rings 40 as well as over the extremities of the end ring portions 38 on the barrel.
  • these end ring portions 38 are formed on the exterior thereof with a circumferential groove 64, and the caps 51 and 52 are provided with a series of small ribs r adapted to snap into the groove 64 when the caps are pressed home so as to act as locks.
  • the extremities 38 of the barrel will be understood to seat against the confronting end wall portions 50 and 51 of the end caps, as clearly shown in the drawings.
  • the end ring portions 38 of the two barrel halves a and 20b are each provided with a pair of pins 66, which project with close fit through corresponding apertures 67 in the end walls of the caps in the assembly of the housing.
  • the outer ends of the apertures 67 are countersunk conically, as indicated at 68, and, initially, the pins 66 project beyond the outer surface of the caps to an extent such as illustrated in FIG. 5.
  • the pins 66 are heated, as by touching them with a suitably shaped hot iron, and so caused to melt and to fill in the conical countersinks 68.
  • the defining surfaces of the latter also soften and melt from the environmental heat, and the material of the pin '66 thus both fills the countersink, and fuses to the defining surfaces of the latter.
  • the initial lengths of the pins 66 are made such that the countersinks are exactly filled, resulting in a flush finished exterior surface as appears in FIG. 6, with the exception that the junction line between the pin and surrounding material has disappeared owing to the fusion.
  • the rims of the caps 17 and 18 are notched, as at 69, to receive and pass the ring terminal tabs 45.
  • the end cap 18 has molded thereon one end of a panel mounting bushing 70- that surrounds the potentiometer shaft 36.
  • This bushing 70 will be further referred to hereinafter.
  • the shaft rotor 34 has on its axial extremity, at the end opposite from shaft 36, an axial stub shaft 72, which is rotatably received in a socket 74 molded in end cap 17.
  • the rotor 34 has, extending longitudinally along each of its two narrow opposite faces, a dove-tail groove 90, in which is confined the angular shank 91 of an electrical conductor 92 (FIGS. 3, 10, and 11).
  • the apex of this shank projects slightly outside the groove 90, and is contacted by a presently described contact member in all positions of the slider along the rotor.
  • a single groove 90 could be provided, and the second, as here shown, is a spare.
  • the extremity of shank 91 carries a yoke 93 bearing two spherically rounded contacts 94 'which ride on slip ring 80.
  • the yoke arms are so formed as to be slightly deflected and to exert light spring pressure on the slip rings to assure good electrical contact.
  • each end cap is formed a spiral ramp 100 whose high end portion is engageable, as at 101, by an edge 102 of the slider to afford an end stop for the slider.
  • An electrical brush or contact 94 (FIGS. 3, 3a, 3b, 9 and 11) is mounted on the rotor 34 to make continuous contact between selected points on the coil 24 and the rotor conductor 92.
  • This contact element which is composed of a resilient electrically conductive metal, comprises a shank 96, with one end portion or arm 97 bent upwardly at a sharp angle (as seen in FIGS. 3 and 9), and formed with a convex tip 98 adapted to contact and ride smoothly along the resistance wire coil.
  • the opposite extremity of the shank 96 is bifurcated, as illustrated, affording two flexible and resilient contact strips.
  • the shank 96 At one side of the shank 96 is a generally box-shaped formation 99, which is adapted for insertion and retention in an aperture 100 of generally similar cross-section formed in the slider 30.
  • the shank extends through suitable clearance space between the slider and rotor so that its flexible bifurcated ends ride on the ridge of the conductor stem 91.
  • the arm 96 bears on the coil, as already described.
  • an external housing including a plastic body having an axial cylindrical bore with a helical groove formed therein, said body being split into a plurality of parts on planes radially disposed relative to the axis of said bore, a preformed resistance wire coil seated in said helical groove, annular axially directed projections on opposite ends of said body, metallic electrically conductive rings tightly fitted onto said projections for holding said body parts in assembly about said coil, with said coil seated in said helical groove, said rings including electrical terminal tabs extending externally of said housing, and electrical connections between the end portions of said coil and said rings.
  • a potentiometer as in claim 2 together with means for securing said end caps to said housing comprising integral pins formed on and extending from said annular projections into said end caps and fused integrally thereto.
  • a potentiometer as in claim 4 wherein a plastic bearing is formed in one of said plastic end caps, and said shaft means is journalled in said plastic bearing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Adjustable Resistors (AREA)
US674043A 1967-09-18 1967-09-18 Helical coil variable potentiometer and method of constructing same Expired - Lifetime US3497855A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US67404367A 1967-09-18 1967-09-18

Publications (1)

Publication Number Publication Date
US3497855A true US3497855A (en) 1970-02-24

Family

ID=24705092

Family Applications (1)

Application Number Title Priority Date Filing Date
US674043A Expired - Lifetime US3497855A (en) 1967-09-18 1967-09-18 Helical coil variable potentiometer and method of constructing same

Country Status (7)

Country Link
US (1) US3497855A (de)
BE (1) BE720944A (de)
CH (1) CH491478A (de)
DE (1) DE6750047U (de)
FR (1) FR1580706A (de)
GB (1) GB1203313A (de)
NL (1) NL6812945A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3932831A (en) * 1974-06-25 1976-01-13 Spectrol Electronics Corporation Variable resistance device

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2495321A (en) * 1945-01-20 1950-01-24 Borg George W Corp Variable resistor
US2859316A (en) * 1956-03-01 1958-11-04 Topp Ind Inc Potentiometer, multiple turn with screw fed slider
US3021494A (en) * 1960-08-05 1962-02-13 Acton Lab Inc Multi-turn potentiometer
US3028571A (en) * 1960-09-28 1962-04-03 Clarostat Mfg Co Inc Multiturn potentiometer
US3058080A (en) * 1961-02-20 1962-10-09 Clarence R Laubenfels Potentiometer
US3064223A (en) * 1960-05-18 1962-11-13 Charles T Gamble Electrical resistor
AT252354B (de) * 1964-08-29 1967-02-27 Telefunken Patent Aus zwei Halbschalen bestehende Kabelschutzmuffe, insbesondere für Fernmeldekabel
US3314036A (en) * 1964-07-24 1967-04-11 Bourns Inc Helical-element variable resistor
US3394336A (en) * 1966-06-14 1968-07-23 Beckman Instruments Inc Housing and terminal construction for variable resistance devices

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2495321A (en) * 1945-01-20 1950-01-24 Borg George W Corp Variable resistor
US2859316A (en) * 1956-03-01 1958-11-04 Topp Ind Inc Potentiometer, multiple turn with screw fed slider
US3064223A (en) * 1960-05-18 1962-11-13 Charles T Gamble Electrical resistor
US3021494A (en) * 1960-08-05 1962-02-13 Acton Lab Inc Multi-turn potentiometer
US3028571A (en) * 1960-09-28 1962-04-03 Clarostat Mfg Co Inc Multiturn potentiometer
US3058080A (en) * 1961-02-20 1962-10-09 Clarence R Laubenfels Potentiometer
US3314036A (en) * 1964-07-24 1967-04-11 Bourns Inc Helical-element variable resistor
AT252354B (de) * 1964-08-29 1967-02-27 Telefunken Patent Aus zwei Halbschalen bestehende Kabelschutzmuffe, insbesondere für Fernmeldekabel
US3394336A (en) * 1966-06-14 1968-07-23 Beckman Instruments Inc Housing and terminal construction for variable resistance devices

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3932831A (en) * 1974-06-25 1976-01-13 Spectrol Electronics Corporation Variable resistance device

Also Published As

Publication number Publication date
GB1203313A (en) 1970-08-26
NL6812945A (de) 1969-03-20
FR1580706A (de) 1969-09-05
BE720944A (de) 1969-03-03
DE6750047U (de) 1969-01-02
CH491478A (de) 1970-05-31

Similar Documents

Publication Publication Date Title
US2410618A (en) Electrical device
US3885149A (en) Lamp pinch seals
US2892992A (en) Printed circuit lamp base
US4209213A (en) Brush holder and slip ring assembly
US2537061A (en) Resistance unit
CA2314459A1 (en) Tubular heating element
US3059214A (en) Connector structure
US3497855A (en) Helical coil variable potentiometer and method of constructing same
US3314036A (en) Helical-element variable resistor
US2815422A (en) Electrical instruments having rotary operating members
US4557536A (en) Rotatable electrical coupling
US2690503A (en) Flashlight reflector assembly for prefocused lamp mounting
EP0179524B1 (de) Elektrische Lampe mit Sockel
KR101447490B1 (ko) 고용량 휴즈
US2419395A (en) Electric lamp
US4849670A (en) Electric lamp having a pinch supported in a sleeve-shared cap
US7118425B2 (en) Socket structure and method for forming the same
US2750483A (en) Resistor bulb
US2821649A (en) Electric lamp base
US3208024A (en) Potentiometer construction
GB2152746A (en) Electric lamp and cap therefor
JP2551887B2 (ja) 電源取出用のカープラグ
JPS5936389B2 (ja) コネクタ−
US3323094A (en) Potentiometer terminal
US2999995A (en) Mechanically variable resistor