US 4,329,676 AGranted

Potentiometer

AssigneeResistance Technology, Inc.

InventorsGerald H. McDonald, Donald R. Hagen

Life of this patent

Estimating the term…

Loading patent…

Abstract

A potentiometer providing a variable electrical resistance between input and output terminals for use in electronic circuits, as for volume control, light control, instrumentation control or the like. A potentiometer includes a housing assembly comprised of a cover assembled to a base. An electrical wiper is mounted to a rotor assembled to the cover and has a contact portion movable along a C-shaped resistive strip on the base. Stops limit the extremes of movement of the wiper with respect to the resistive strip. An annular seal disposed between the cover and a rotating portion of the rotor is effective to keep out dirt and other particulate matter from the potentiometer and provides continuous brake friction upon rotation of the rotor. In one form of the potentiometer, the housing assembly includes a body located between the cover and base and a switch mechanism is operably connected to the rotor to selectively locate an electrical contact in an on or off position.

Claims46

Dependent claims

A potentiometer comprising:

housing means having a chamber;
a rotor having a stem rotatably assembled on the housing means, said stem extending into the chamber and said rotor having a portion extending outside of the chamber and housing means for manual manipulation to rotate the stem;
an electrical wiper located on the stem, said wiper having a contact portion;
a C-shaped resistive strip mounted on the housing means in the chamber, said strip having a first end and a second end with variable electrical resistance means between the first end and the second end;
first terminal means electrically connected to the wiper;
second terminal means electrically connected to the resistive strip;
said wiper having contact means in engagement with the resistive strip and rotatable with the rotor stem from the first end of the resistive strip to the second end of the resistive strip whereby the resistance between the first terminal means and the second terminal means is varied;
annular resilient means cooperating with the housing means and rotor for continuous friction braking said rotor;
and means attached to the housing means and engageable with the rotor for limiting rotation of the rotor to allow the contact portion to move between the first end and second end of the resistive strip, said means attached to the housing means for limiting rotation of the rotor between first and second positions, and second means attached to the housing means engageable with the wiper to limit rotation of the wiper between the first and second ends of the resistive strip, said wiper engaging said second means on initial rotation of the rotor to hold the wiper in an end position until the rotor engages the first means whereby the wiper is circumferentially oriented with the rotor.

6 more elements

A potentiometer comprising:

housing means having a chamber;
a rotor having a stem rotatably assembled on the housing means, said stem extending into the chamber and said rotor having a portion extending outside of the chamber and housing means for manual manipulation to rotate the stem;
an electrical wiper located on the stem, said wiper having a contact portion;
a C-shaped resistive strip mounted on the housing means in the chamber, said strip having a first end and a second end with variable electrical resistance means between the first end and the second end;
first terminal means electrically connected to the wiper;
second terminal means electrically connected to the resistive strip;
said wiper having contact means in engagement with the resistive strip and rotatable with the rotor stem from the first end of the resistive strip to the second end of the resistive strip whereby the resistance between the first terminal means and the second terminal means is varied;
annular resilient means cooperating with the housing means and rotor for continuous friction braking said rotor;
and means attached to the housing means and engageable with the rotor for limiting rotation of the rotor to allow the contact portion to move between the first end and second end of the resistive strip, said housing means having annular groove means open to a portion of the rotor, said annular groove means comprising a first groove having a bottom and an open top facing said portion of the rotor, and a second groove in the bottom of the first groove, said bottom having annular portions located adjacent opposite sides of the second groove, said annular resilient means being located in said first groove in engagement with said annular portions and expandable into said second groove.

6 more elements

A potentiometer comprising:

housing means having a chamber;
a rotor having a stem rotatably assembled on the housing means, said stem extending into the chamber and said rotor having a portion extending outside of the chamber and housing means for manual manipulation to rotate the stem;
an electrical wiper located on the stem, said wiper having a contact portion;
a C-shaped resistive strip mounted on the housing means in the chamber, said strip having a first end and a second end with variable electrical resistance means between the first end and the second end;
first terminal means electrically connected to the wiper;
second terminal means electrically connected to the resistive strip;
said wiper having contact means in engagement with the resistive strip and rotatable with the rotor stem from the first end of the resistive strip to the second end of the resistive strip whereby the resistance between the first terminal means and the second terminal means is varied;
annular resilient means cooperating with the housing means and rotor for continuous friction braking said rotor;
means attached to the housing means and engageable with the rotor for limiting rotation of the rotor to allow the contact portion to move between the first end and second end of the resistive strip, and a switch mechanism cooperating with the stem operable to open an electrical circuit in response to rotation of the rotor to a selected position, said switch mechanism including a cam mounted on the stem, first contact means and second contact means mounted on the housing means, said cam being movable into engagement with the first contact means to separate the first contact means from the second contact means to open said electrical circuit.

6 more elements

A potentiometer comprising:

housing means having a chamber, a rotor having a stem rotatably mounted on the housing means, said stem extended into the chamber, said rotor having a head located adjacent a portion of the housing means outside of the chamber for manual manipulation of the rotor, an electrical wiper located on the stem, said wiper having a contact portion, an electrical resistive strip mounted on the housing means in the chamber, said strip having first and second ends and variable electrical resistive means between the first end and second end thereof, a first set of terminals electrically connected to said wiper, a second set of terminals electrically connected to said wiper, said wiper having a contact portion in engagement with resistive strip and rotatable upon the rotor stem from the first end of the resistive strip to the second end of the resistive strip whereby the resistance between the first set of terminals and the second set of terminals is varied, said housing means having an annular groove open to said surface of the head, an annular seal located in said groove, said annular seal having an annular portion located in sliding contact with said surface of the head to frictionally hold said head in a selected position, and means attached to the housing means for limiting rotation of the rotor comprising an arcuate rib having end shoulders engageable with the wiper to limit rotation of the wiper and stop movement of the contact portion of the wiper beyond the first and second ends of the resistive strip, said arcuate rib having an arcuate surface engageable with an arcuate portion of the resistive strip to locate the strip on the housing means.

A potentiometer comprising:

housing means having a chamber, a rotor having a stem rotatably mounted on the housing means, said stem extended into the chamber, said rotor having a head located adjacent a portion of the housing means outside of the chamber for manual manipulation of the rotor, an electrical wiper located on the stem, said wiper having a contact portion, an electrical resistive strip mounted on the housing means in the chamber, said strip having first and second ends and variable electrical resistive means between the first end and second end thereof, first set of terminals electrically connected to said wiper, a second set of terminals electrically connected to said wiper, said wiper having a contact portion in engagement with resistive strip and rotatable upon the rotor stem from the first end of the resistive strip to the second end of the resistive strip whereby the resistance between the first set of terminals and the second set of terminals is varied, said housing means having an annular groove open to said surface of the head, an annular seal located in said groove, said annular seal having an annular portion located in sliding contact with said surface of the head to frictionally hold said head in a selected position, first means attached to the housing means for limiting rotation of the rotor between first and second positions, said first means including a pair of stops on the outside of the housing means, said rotor having a tab selectively engageable with said stops to limit rotation of said rotor, and second means attached to the housing means engageable with the wiper to limit rotation of the wiper between the first and second ends of the resistive strip, said wiper engaging said second means on initial rotation of the rotor to hold the wiper in an end position until the rotor engages the first means whereby the wiper is circumferentially orientated with the rotor.

Dependencies are inferred from the claim text.