Patent US3746810A successfully refreshed from Google Patents.
US3746810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure operated electric switches with flexible helical bridging contact
Assignee: Whitnash PLC
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Filing: 1971-07-28
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Granted: 1973-07-17
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Expires: 1991-07-28
Abstract
Abstract A pressure operated electric switch having two sets of contacts operated at different pressures acting on the switch, comprises a helical conductor in permanent contact with a first fixed contact and normally held out of engagement with a second and a third fixed contact by a plunger which is responsive to the operating fluid pressure. Movement of the plunger following a suitable reduction in the operating fluid pressure first brings the helical conductor into engagement with the second fixed contact and subsequently with the third fixed contact. The plunger may be arranged to disengage from the helical conductor when the latter is engaged with both the second and the third fixed contacts, or the plunger may be arranged to make part of the circuit between the first and second fixed contacts.
Inventors
- 👤 D Parsons
- 👤 W Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:00
CPC Classifications
H; H01; H01H; H01H35/00; H01H35/24; H01H35/26; H01H35/2657; H01H35/38
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
196 words
A pressure operated electric switch comprising a plunger adapted to be subjected to an operating fluid pressure, resilient means acting on said plunger to oppose the said operating fluid pressure, first, second and third fixed contact members, a flexible helical conductor bridging contact member having one of its end turns in permanent contact with said first contact member and associated with said plunger so that movement of said plunger in one direction from a position in which said flexible bridging contact member engages only said first fixed contact member, first completes an electrical connection between said first and second fixed contact members through said flexible bridging contact member, and subsequently completes an electrical connection between said first and third contact members through said flexible bridging contact member, said electrical connection between said first fixed contact member and said second fixed conteact member through flexible bridging contact member being maintained during subsequent movement of said plunger in said one direction so said first fixed contact membeR is connected to both said second and said third fixed contact members through said flexible bridging contact member once the electrical connection to said third fixed contact member has been completed.
Claim 2
Dependent Claim
196 words
A pressure operated electric switch comprising a plunger adapted to be subjected to an operating fluid pressure, resilient means acting on said plunger to oppose the said operating fluid pressure, first, second and third fixed contact members, a flexible helical conductor bridging contact member having one of its end turns in permanent contact with said first contact member and associated with said plunger so that movement of said plunger in one direction from a position in which said flexible bridging contact member engages only said first fixed contact member, first completes an electrical connection between said first and second fixed contact members through said flexible bridging contact member, and subsequently completes an electrical connection between said first and third contact members through said flexible bridging contact member, said electrical connection between said first fixed contact member and said second fixed conteact member through flexible bridging contact member being maintained during subsequent movement of said plunger in said one direction so said first fixed contact membeR is connected to both said second and said third fixed contact members through said flexible bridging contact member once the electrical connection to said third fixed contact member has been completed.
Claim 3
Dependent Claim
123 words
The pressure operated electric switch of claim 1, wherein two spaced portions of the end turn of the helical conductor remote from the first fixed contact member co-operate respectively with the second and third fixed contact members, the resilient loading of the helical conductor being sufficient to hold each said spaced portion in electrical contact with the respective one of the second and third fixed contact members, and means define spaced abutments which are moveable axially with movement of the plunger, the arrangement being such that each said spaced portion can be engaged by a respective one of the spaced abutments and held spaced from the respective one of the second and third contact members against the resilient loading of the helical conductor.
Claim 4
Dependent Claim
125 words
The pressure operated electric switch of claim 2, wherein the two spaced portions of said end turn of the helical conductor co-operate with axially aligned radially extending portions of the second and third fixed contact members, the spaced abutments comprising spaced portions of a shoulder defined by a contact control member which is moveable axially with movement of the plunger, the shoulder being stepped so that the spaced shoulder portion which is adapted to hold the respective end turn portion of the helical conductor spaced from the third fixed contact member is nearer the first fixed contact member than is the spaced shoulder portion which is adapted to hold the respective end turn portion of the helical conductor spaced from the second fixed contact member.
Claim 5
Dependent Claim
128 words
The pressure operated electric switch of claim 2, wherein the two spaced portions of said end turn of the helical conductor co-operate with axially aligned radially extending portions of the second and third fixed contact members, the spaced abutments comprising spaced portions of a shoulder defined by a contact control member which is movable axially with movement of the plunger, the shoulder being inclined to the axis, so that the spaced shoulder portion which is adapted to hold the respective end turn portion of the helical conductor spaced from the third fixed contact member is nearer the first fixed contact member than is the spaced shoulder portion which is adapted to hold the respective end turn portion of the helical conductor spaced from the second fixed contact member.
Claim 6
Dependent Claim
29 words
The pressure operated electric switch of claim 4, wherein the diameter of one end turn of the helical conductor is greater than the diameter of the other end turn.
Claim 7
Dependent Claim
50 words
The pressure operated electric switch of claim 5, wherein the helical conductor is connected to the first fixed contact member by the large diameter end turn, the first fixed contact member being located between and being spaced axially from the second fixed contact member and the third fixed contact member.
Claim 8
Dependent Claim
171 words
The pressure operated electric switch of claim 6, wherein when the helical conductor is connected only to the first fixed contact member the fluid pressure operated plunger is arranged to hold a coaxial secondary plunger against the loading of a spring by which the co-axial secondary plunger is connected electrically with the second fixed contact member, and thus to hold the secondary plunger spaced from the smaller diameter and turn of the helical conductor with which it is adapted to co-operate, the arrangement being such that movement of the secondary plunger with movement of the fluid pressure operated plunger in said one direction first brings the secondary plunger into electrical contact with the smaller diameter turn of the helical conductor so as to complete the electrical connection between the first and second fixed contact members and then moves the smaller diameter turn of the helical conductor axially into electrical contact with the third fixed contact member so as to comPlete the electrical connection between the first and third fixed contact members.
Claim 9
Dependent Claim
63 words
The pressure operated electric switch of claim 7, wherein a separate spring acts to urge the smaller diameter end turn of the helical conductor away from the third fixed contact member and to hold the smaller diameter turn of the helical spring in contact with the first fixed contact member when the helical conductor is connected only to said first fixed contact member.
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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) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |