Patent US3670960A successfully refreshed from Google Patents.
US3670960A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control apparatus
Assignee: Robertshaw Controls Co
•
Filing: 1970-09-14
•
Granted: 1972-06-20
•
Expires: 1990-09-14
Abstract
Abstract A control apparatus comprising a switch controlling current flow to an inductance means which is coupled with a controlled element. A free wheeling resistor is connected in parallel with the inductance means and defines a path for reverse flow of induced current therethrough during collapse of the magnetic field in the inductance means. A heat responsive control circuit is provided for controlling a controlled device and includes a heat responsive element disposed in heat exchange relationship with the resistor whereby when the switch is turned on current during positive going half cycles will be directed through both the resistor and inductance means, and the current induced by collapse of the magnetic field in the inductance means will flow in the reverse direction through the resistor thereby permitting continued flow in the forward direction through the inductance means and after a selected time the self-heating of the resistor will heat the temperature responsive element to actuate the control circuit and, consequently, the controlled device.
Inventors
- 👤 William W Chambers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:20
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/30; G05D23/303
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
186 words
Control apparatus to be connected with an AC source for actuating an operator, said apparatus comprising: switch means connected with said AC source and operative in response to application of AC current to produce a pulsating DC output; inductance means connected with said switch means and coupled with said operator; a control circuit for operating a controlled device and including a heat responsive element operative upon reaching a selected temperature to actuate said controlled device; and a free wheeling resistor connected in shunt relationship with said inductance means and defining a return path for the reverse flow of induced current, said resistor being disposed in heat exchange relationship with said heat responsive element whereby upon operation of said switch means, a magnetic field builds up in said inductance means during fractional cycles of increasing amplitude of said pulsating direct current and said resistor provides a path for the flow of current induced by the collapse of said magnetic field during fractional cycles of decreasing amplitude and after a predetermined time said resistor will be heated sufficiently to cause said control circuit to actuate said controlled device.
Claim 2
Dependent Claim
186 words
Control apparatus to be connected with an AC source for actuating an operator, said apparatus comprising: switch means connected with said AC source and operative in response to application of AC current to produce a pulsating DC output; inductance means connected with said switch means and coupled with said operator; a control circuit for operating a controlled device and including a heat responsive element operative upon reaching a selected temperature to actuate said controlled device; and a free wheeling resistor connected in shunt relationship with said inductance means and defining a return path for the reverse flow of induced current, said resistor being disposed in heat exchange relationship with said heat responsive element whereby upon operation of said switch means, a magnetic field builds up in said inductance means during fractional cycles of increasing amplitude of said pulsating direct current and said resistor provides a path for the flow of current induced by the collapse of said magnetic field during fractional cycles of decreasing amplitude and after a predetermined time said resistor will be heated sufficiently to cause said control circuit to actuate said controlled device.
Claim 3
Dependent Claim
45 words
Control apparatus as set forth in claim 1 wherein: said operator controls a heater; and said controlled device includes circulation means for circulating fluid in heat exchange relationship with said heater whereby said circulation means will be actuated only after said heater has been actuated.
Claim 4
Dependent Claim
83 words
Control apparatus as set forth in claim 1 wherein said operator is adapted to operate a temperature change apparatus and wherein: said switching means comprises a silicon controlled rectifier; and wherein said control circuit is in the form of a bridge having a temperature responsive sensor connected with the gate of said silicon controlled rectifier and operative to impose a triggering signal on said gate when the temperature of the environment within which said sensor is disposed falls outside a predetermined temperature range.
Claim 5
Dependent Claim
132 words
Control apparatus as set forth in claim 1 wherein said operator operates a heater and wherein said apparatus further includes: a second operator for actuating an air conditioning means; a second inductance means connected with said switch means and coupled with said second operator; a second free wheeling resistor connected in shunt relationship with said second operator; and a sensing circuit including a temperature sensor for sensing the environmental temperature, said sensing circuit being operative, upon said sensor being heated above a predetermined temperature, to actuate said switch means and direct current flow through said first-mentioned inductance means and first-mentioned resistor, and being further operative upon cooling of said sensor below a selected temperature to actuate said switch means and direct current flow through said second inductance means and said second resistor.
Claim 6
Dependent Claim
73 words
Control apparatus as set forth in claim 4 wherein: said controlled device includes a blower fan for selectively blowing air in heat exchange relationship with said heater or said air conditioning means; and said control circuit is connected with said fan and includes a second heat responsive element disposed in heat exchange relationship with saiD second free wheeling resistor and responsive to heating thereof to actuate said control circuit and operate said fan.
Claim 7
Dependent Claim
17 words
Control apparatus as set forth in claim 4 wherein: said switch means comprises a silicon controlled rectifier.
Claim 8
Dependent Claim
17 words
Control apparatus as set forth in claim 5 wherein: said switch means comprises a silicon controlled rectifier.
Claim 9
Dependent Claim
17 words
Control apparatus as set forth in claim 1 wherein: said free wheeling resistor is a non-rectifying element.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |