US3840834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protector/indicator using ptc heater and thermostatic bimetal combination
Assignee: Texas Instruments Inc
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Filing: 1972-12-18
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Granted: 1974-10-08
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Expires: 1992-12-18
Abstract
Abstract An indicator and/or protector uses a PTC heater and a bimetallic device in combination. As an indicator, power is passed through a PTC pill, the pill being thermally coupled to the bimetallic device. Upon sufficient transfer of heat from the pill to the bimetallic device, a spring biased flag which is latched by the bimetallic device becomes unlatched and provides an indicator of this condition. The flag must be manually reset. A further embodiment includes the bimetallic device as a portion of a switch wherein, when the snapping temperature of the bimetallic device has been reached, the switch can be opened, thereby providing a protection function in addition to the indicator.
Inventors
- 👤 R Obenhaus
- 👤 D Squiers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:38
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16566; G01R19/16571; H; H01; H01H; H01H61/00; H01H61/01; H01H61/013; H01H71/00; H01H71/10; H01H71/12; H01H71/14; H01H71/16; H01H71/164
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
110 words
An alarm indicator which comprises, a. a base member, b. indicator means positioned in said base member biased to extend out of said base member, c. latching means secured to said base member for normally latching said indicator means in said base member, said latching means being a bimetallic device, d. a PTC heater, thermally coupled to said latching means, for causing said latching means to unlatch said indicator means responsive to a predetermined condition of said heater, e. means to apply current across said heater, f. a load terminal, and g. a switch connected in series with said load terminal, said latching means forming a portion of said switch.
Claim 2
Dependent Claim
110 words
An alarm indicator which comprises, a. a base member, b. indicator means positioned in said base member biased to extend out of said base member, c. latching means secured to said base member for normally latching said indicator means in said base member, said latching means being a bimetallic device, d. a PTC heater, thermally coupled to said latching means, for causing said latching means to unlatch said indicator means responsive to a predetermined condition of said heater, e. means to apply current across said heater, f. a load terminal, and g. a switch connected in series with said load terminal, said latching means forming a portion of said switch.
Claim 3
Dependent Claim
113 words
An alarm indicator which comprises, a. a base member, b. indicator means positioned in said base member biased to extend out of said base member, c. latching means secured to said base member for normally latching said indicator means in said base member, d. a PTC heater, thermally coupled to said latching means, for causing said latching means to unlatch said indicator means responsive to a predetermined condition of said heater, e. means to apply current across said heater, and f. a load terminal and a switch connected in series with said load terminal, said latching means forming a portion of said switch, said load terminal being electrically isolated from said PTC heater.
Claim 4
Dependent Claim
113 words
An alarm indicator which comprises, a. a base member, b. indicator means positioned in said base member biased to extend out of said base member, c. latching means secured to said base member for normally latching said indicator means in said base member, d. a PTC heater, thermally coupled to said latching means, for causing said latching means to unlatch said indicator means responsive to a predetermined condition of said heater, e. means to apply current across said heater, and f. a load terminal and a switch connected in series with said load terminal, said latching means forming a portion of said switch, said load terminal being electrically isolated from said PTC heater.
Claim 5
Dependent Claim
119 words
An alarm indicator which comprises, a. a base member, b. indicator means positioned in said base member biased to extend out of said base member, c. latching means secured to said base member for normally latching said indicator means in said base membeR, said latching means being a bimetallic device, d. a PTC heater, thermally coupled to said latching means, for causing said latching means to unlatch said indicator means responsive to a predetermined condition of said heater, e. means to apply current across said heater, and f. a load terminal, and a switch connected in series with said load circuit, said latching means forming a portion of said switch, said switch being electrically isolated from said PTC heater.
Claim 6
Dependent Claim
119 words
An alarm indicator which comprises, a. a base member, b. indicator means positioned in said base member biased to extend out of said base member, c. latching means secured to said base member for normally latching said indicator means in said base membeR, said latching means being a bimetallic device, d. a PTC heater, thermally coupled to said latching means, for causing said latching means to unlatch said indicator means responsive to a predetermined condition of said heater, e. means to apply current across said heater, and f. a load terminal, and a switch connected in series with said load circuit, said latching means forming a portion of said switch, said switch being electrically isolated from said PTC heater.
Claim 7
Dependent Claim
96 words
An alarm indicator comprising: a base member, indicator means mounted on said base member for reciprocal motion and biased to extend out of said base member, a thermally responsive latching means disposed on said base member and adapted to prevent said indicating means from extending out of said base member when said latching means is in a latched position, a PTC heater thermally coupled to said latching means for causing said latching means to unlatch said indicating means responsive to a predetermined condition of said heater, and terminal means to apply current across said PTC heater.
Claim 8
Dependent Claim
96 words
An alarm indicator comprising: a base member, indicator means mounted on said base member for reciprocal motion and biased to extend out of said base member, a thermally responsive latching means disposed on said base member and adapted to prevent said indicating means from extending out of said base member when said latching means is in a latched position, a PTC heater thermally coupled to said latching means for causing said latching means to unlatch said indicating means responsive to a predetermined condition of said heater, and terminal means to apply current across said PTC heater.
Claim 9
Dependent Claim
57 words
An alarm indicator according to claim 4 in which said latching means comprises a bimetal member having two ends one end of which is electrically connected to one of said terminal means, a stationary contact mounted on the base, the other end of the bimetal member engageable with said stationary contact when the indicator means is latched.
Claim 10
Dependent Claim
42 words
An alarm indicator according to claim 5 in which the indicator means includes at least a portion of electrically insulative material which is interposed between the other end of the bimetal member and the stationary contact when the indicator means is unlatched.
Claim 11
Dependent Claim
22 words
An alarm indicator according to claim 6 in which the PTC heater is electrically isolated from the stationary contact and bimetal member.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |