US3582857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Worm-driven adjustable potentiometers
Assignee: CORNELL-DUBIILIER MARKETING Inc
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Filing: 1968-09-27
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Granted: 1971-06-01
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Expires: 1988-09-27
Abstract
Abstract A low-cost, worm-driven potentiometer is described which may be constructed using only a few components and yet retains good performance characteristics. Components which are conventionally used in this type of potentiometer, but which may at least be omitted in accordance with the instant invention without deleteriously affecting performance characteristics, especially the specific tolerance of resolution, include axial constraints for preventing the driving worm from moving axially in the potentiometer housing. This is made possible by utilizing a wormdrive comprising a driving worm having a threaded section of hourglass profile and a driven spur gear. The meshing engagement between the worm and gear is preferably effected with at least an interference tooth contact and the hourglass worm-drive provides self-nullification of axially directed forces which would tend to cause resultant axial displacements of the worm upon worm rotation. Further simplification is made possible by utilizing a collector pin as the axial support for the driven gear and as a means for preventing the overdriving of a contact element rotatable with the driven gear. Moreover, the contact element cooperates with the collector pin to provide a resilient axial support for the driven gear.
Inventors
- 👤 Joseph F Kishel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:01
CPC Classifications
H; H01; H01C; H01C10/00; H01C10/14; Y; Y10; Y10S; Y10S338/00; Y10S338/01
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
297 words
In an adjustable resistor, the combination of: housing means; resistance means; movable contact means; a driven member for operating said movable contact means, said driven member having an arcuate peripheral portion with a plurality of teeth; a driving worm; said housing means defining a worm-accommodating bore and a cavity, said bore opening at one end to the exterior of said housing means, a first portion of said housing means defining said bore presenting a right cylindrical bearing surface, a second portion of said housing means defining said bore defining an inner bore portion, said bearing surface being located between said one end of the bore and said inner bore portion, said second portion of said housing means being so constructed as to provide lateral communication between said inner bore portion and said cavity; said resistance means, said movable contact means and said driven member being disposed in said cavity, said contact means operatively engaging said resistance means, said driven member being arranged to effect relative movement between said contact means and said resistance means; said driving worm comprising: a head end exposed at said one end of said bore, a right cylindrical journal portion embraced by and engaged in bearing relationship with said bearing surface, and a threaded portion of substantially hourglass profile, and stop means operatively arranged to restrain movement of said driven member; said threaded portion of said worm being meshed with a plurality of teeth of said driven member; the maximum diameter of said threaded portion of said worm not exceeding the diameter of said journal portion of said worm, and said worm being substantially free for axial movement relative to said housing means in a direction outwardly of said bore save for said meshed engagement of said threaded portion with said driven member.
Claim 2
Dependent Claim
297 words
In an adjustable resistor, the combination of: housing means; resistance means; movable contact means; a driven member for operating said movable contact means, said driven member having an arcuate peripheral portion with a plurality of teeth; a driving worm; said housing means defining a worm-accommodating bore and a cavity, said bore opening at one end to the exterior of said housing means, a first portion of said housing means defining said bore presenting a right cylindrical bearing surface, a second portion of said housing means defining said bore defining an inner bore portion, said bearing surface being located between said one end of the bore and said inner bore portion, said second portion of said housing means being so constructed as to provide lateral communication between said inner bore portion and said cavity; said resistance means, said movable contact means and said driven member being disposed in said cavity, said contact means operatively engaging said resistance means, said driven member being arranged to effect relative movement between said contact means and said resistance means; said driving worm comprising: a head end exposed at said one end of said bore, a right cylindrical journal portion embraced by and engaged in bearing relationship with said bearing surface, and a threaded portion of substantially hourglass profile, and stop means operatively arranged to restrain movement of said driven member; said threaded portion of said worm being meshed with a plurality of teeth of said driven member; the maximum diameter of said threaded portion of said worm not exceeding the diameter of said journal portion of said worm, and said worm being substantially free for axial movement relative to said housing means in a direction outwardly of said bore save for said meshed engagement of said threaded portion with said driven member.
Claim 3
Dependent Claim
26 words
The combination according to claim 1, wherein said driving worm is of a material having a hardness substantially greater than the material of said driven member.
Claim 4
Dependent Claim
24 words
The combination according to claim 2, wherein said driving worm is of metal and said driven member is of a resiliently deformable synthetic resin.
Claim 5
Dependent Claim
32 words
The combination according to claim 1, wherein said driven member is a gear having equally spaced teeth the contact surfaces of which are perpendicular to the plane of rotation of the gear.
Claim 6
Dependent Claim
243 words
In an adjustable resistor, the combination of: housing means defining a bore and a cavity; said bore opening at one end to the exterior of said housing means and having an inner portion in communication with said cavity; an arcuate resistance element mounted in said cavity; rotary contact means; a driven gear mounted in said cavity for rotary movement about a fixed axis, said contact means slidably engaging said resistance element and said gear being connected to said contact means to move the same relative to said resistance element when said gear is turned; a driving worm disposed in said bore and comprising: a head end exposed at said one end of said bore, and a threaded portion of substantially hourglass profile disposed in meshed engagement with a plurality of teeth of said gear; and means operatively arranged to resist turning of said gear when said contact means has been moved to a predetermined rotational position relative to said resistance element, the wall of said bore slidably embracing said driving worm to support the same for rotation about the longitudinal axis of said bore while restraining the same against lateral movement, said driving worm being positively constrained against axial movement in said bore, when said means to resist turning of said gear acts to resist movement of said gear at a time when a turning force is still applied to the worm, by the meshed engagement of said threaded portion with said gear.
Claim 7
Dependent Claim
243 words
In an adjustable resistor, the combination of: housing means defining a bore and a cavity; said bore opening at one end to the exterior of said housing means and having an inner portion in communication with said cavity; an arcuate resistance element mounted in said cavity; rotary contact means; a driven gear mounted in said cavity for rotary movement about a fixed axis, said contact means slidably engaging said resistance element and said gear being connected to said contact means to move the same relative to said resistance element when said gear is turned; a driving worm disposed in said bore and comprising: a head end exposed at said one end of said bore, and a threaded portion of substantially hourglass profile disposed in meshed engagement with a plurality of teeth of said gear; and means operatively arranged to resist turning of said gear when said contact means has been moved to a predetermined rotational position relative to said resistance element, the wall of said bore slidably embracing said driving worm to support the same for rotation about the longitudinal axis of said bore while restraining the same against lateral movement, said driving worm being positively constrained against axial movement in said bore, when said means to resist turning of said gear acts to resist movement of said gear at a time when a turning force is still applied to the worm, by the meshed engagement of said threaded portion with said gear.
Claim 8
Dependent Claim
112 words
The combination according to claim 5, wherein: said contact means includes a contact element comprising a fixed portion disposed generally at the center of one face of said gear; the combination further comprises a collector terminal including a first portion extending within said cavity generally parallel to the axis of rotation of said gear and a second portion projecting laterally from said first portion and slidably engaging said fixed portion of said contact element; said means to resist turning of said gear comprising a projection carried by said gear and disposed to be brought into engagement with said second portion of said collector terminal as a result of rotation of said gear.
Claim 9
Dependent Claim
43 words
The combination according to claim 5, wherein: said driving worm is of metal; said gear is of resiliently deformable synthetic resin; and the teeth of said gear and said threaded portion of said worm are disposed in meshed engagement with an interference fit.
Claim 10
Dependent Claim
252 words
In an adjustable resistor, the combination of: housing means defining a cavity and a bore; said bore opening at one end to the exterior of said housing means, an inner portion of said bore communicating with said cavity, the wall of said bore between said inner portion and said one end being right cylindrical; an arcuate resistance element mounted in said cavity; a gear mounted in said cavity for rotation about a fixed axis, said gear being of resiliently deformable synthetic resin; a rotary contact member disposed in said cavity, said gear driving said contact member and said contact member slidably engaging said resistance element; a driving worm disposed in said bore and comprising: a head end exposed at said one end of said bore, a right cylindrical portion journaled in said right cylindrical wall of said bore, and a threaded portion of substantially hourglass profile disposed axially inwardly of said right cylindrical wall of said bore, said threaded portion having a maximum diameter not exceeding the diameter of said right cylindrical wall of said bore, said threaded portion of said worm being meshed with a substantial number of teeth of said gear; and stop means arranged to restrain said gear against rotation when said contact member has been moved to a last-mentioned relative to said resistance element, said worm being constrained against axial movement outwardly, toward said one end, when said gear is restrained by said last-mentioned means, by reason of the meshed engagement between said threaded portion and said gear.
Claim 11
Dependent Claim
252 words
In an adjustable resistor, the combination of: housing means defining a cavity and a bore; said bore opening at one end to the exterior of said housing means, an inner portion of said bore communicating with said cavity, the wall of said bore between said inner portion and said one end being right cylindrical; an arcuate resistance element mounted in said cavity; a gear mounted in said cavity for rotation about a fixed axis, said gear being of resiliently deformable synthetic resin; a rotary contact member disposed in said cavity, said gear driving said contact member and said contact member slidably engaging said resistance element; a driving worm disposed in said bore and comprising: a head end exposed at said one end of said bore, a right cylindrical portion journaled in said right cylindrical wall of said bore, and a threaded portion of substantially hourglass profile disposed axially inwardly of said right cylindrical wall of said bore, said threaded portion having a maximum diameter not exceeding the diameter of said right cylindrical wall of said bore, said threaded portion of said worm being meshed with a substantial number of teeth of said gear; and stop means arranged to restrain said gear against rotation when said contact member has been moved to a last-mentioned relative to said resistance element, said worm being constrained against axial movement outwardly, toward said one end, when said gear is restrained by said last-mentioned means, by reason of the meshed engagement between said threaded portion and said gear.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |