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Publication numberUS3851149 A
Publication typeGrant
Publication dateNov 26, 1974
Filing dateNov 29, 1973
Priority dateNov 29, 1973
Publication numberUS 3851149 A, US 3851149A, US-A-3851149, US3851149 A, US3851149A
InventorsDaley W
Original AssigneeSmith Gates Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrical heating cable with indicator light and manual test device
US 3851149 A
Abstract
An elongated flexible electrical resistance heating cable adapted to be wrapped about water pipes and for other similar uses. A cold lead extends to the cable and a thermostat is interposed between the cold lead and the cable with a translucent and flexible envelope thereabout. A small indicator light within a second translucent envelope is connected in parallel with the heating cable and operates to reflect visually operation of the thermostat. A test device in the first envelope comprises a small spring metal conductor connected at one end with one thermostat terminal and having an opposite end movable toward and away from a second thermostat terminal. Manual deflection of the envelope against the conductor urges the same into contact with the terminal whereby to close the circuit for testing of the heating cable and release of manual pressure opens the circuit.
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United States Patent [191 Daley I NOV. 26, 1974 ELECTRICAL HEATING CABLE WITH INDICATOR LIGHT AND MANUAL TEST DEVICE [75] Inventor: William Carmen Daley, West Hartford, Conn.

[73] Assignee: Smith-Gates Corporation,

Farmington, Conn.

[22] Filed:

Nov. 29, 1973 21 Appl. No.: 420,263

52 user 219/528, 200/168 0,219/506, 219/535, 340/252 P 511 lnt.Cl. H05b3/36, H05b 3/56 [58] Field of Search 200/168 G; 219/528, 506, 219/535, 549; 338/214; 340/252 R, 252 H,

[56] References Cited UNITED STATES PATENTS 2,696,607 12/1954 Witkin 340/252 P 2,752,463. 6/1956 Staak 2,824,209 2/1958 Leipold 2,977,456 3/1961 Stiebel 200/168 G 3,246,] 12 4/1966 200/168 G Adams et a1 3,305,668 2/1967 Smith 219/528 Primary Examiner-Volodymyr Y. Mayewsky Attorney, Agent, or Firm-McCormick, Paulding and Huber [5 7] ABSTRACT An elongated flexible electrical resistance heating cable adapted to be wrapped about water pipes and for other similar uses. A cold lead extends to the cable and a thermostat is interposed between the cold lead and the cable with a translucent and flexible envelope thereabout. A small indicator light within a second translucent envelope is connected in parallel with the heating cable and operates to reflect visually operation of the thermostat. A test device in the first envelope comprises a small spring metal conductor connected at one end with one thermostat terminal and having an opposite end movable toward and away from a second thermostat terminal. Manual deflection of the envelope against the conductor urges the same into contact with the terminal whereby to close the circuit for testing of the heating cable and release of manual pressure opens the circuit.

3 Claims, 3 Drawing Figures E E T ICAL HEATING CABLE WITH INDICATOR LIGHT AN MANUAL TEST DEVICE BACKGROUND OF THE INVENTION Electrical heating cables of the resistance type have been .available heretofore and have proven generally satisfactory. A convenient determination of availability of electricalpower, operability of the thermostat, and operability of the resistance heating element has not, however, been possible with such heating cables, the cables often being disposed about water pipes beneath house trailers andin other inaccessible locations.

- SUMMARY OF THE INVENTION It is the. general object of the present invention to provide an electrical resistance heating cable of the type mentioned wherein provision is madefor the convenient visual indication of the availability of electrical power supply, operability of a thermostat, and wherein the operability of the resistance heating element may be readily ascertained.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring particularly to FIG. 1', an electrical resistance heating cable is indicated generally at 10. The cable takes a tape-like form in cross section with electrieal resistance heating element 12 disposed therewithin and a flexible insulator 14 forming the sheath or outer portion thereof. Both the resistance heating element and the insulator 14 are elongated and of indeterminant length extending from a substantially translucent first envelope 16. The cable or tape may obviously be woundconveniently in a spiral configuration about a water pipe subject to freezing temperatures, embedded in seed beds, etc.

The translucent envelope 16, as best illustrated in FIG. 2, takes a pillow configuration and is preferably heat sealed at end portions 18, about and in engage- .ment with the cable 10 and other elements. In FIG. 3, and at the left-hand heat sealed area 18 in particular, a cold lead 22, 24 is captured within the heat sealed area and extends therefrom to a conventional electrical plug 26, FIG. 1. The right-hand heat sealed area 20 captures, in addition to the heating cable 10, first and "second electrical conductors 28, 30 which extend from clips 32, 34 to a second substantially translucent envelope 36, best illustrated in FIG. 1. The'clips 32, 34 serve respectively to connect the conductors 28. and an associated 'endportion of resistance element 12 with the cold lead 22 and, to connect the conductor 30 and associated opposite end portion of resistance element cent envelope 36 by means of the conductors 28, 30.

The thermostat 40 may be of a conventional construction and operates to energize the heating element 7 12 below a predetermined temperature whereby to prevent-freezing of water pipes or to effect heating of the element 12 for other end purposes. Preferably and as shown, the thermostat 40 has at least one exposed terminal and, left and right-hand or first and second ex posed terminals are shown. The left-hand terminal 42 is exposed for a purpose to be set forth hereinhelow and the aforementionedterminal 38 may also be-cxposed. The cold lead 24 is connected with the left-hand terminal 42 by means of a suitable clip 44.

A test device incorporated in the heating cable assembly of the present invention is preferably manually operable and may comprise a spring metal conductor as illustrated at 46. The spring metal conductor 46 has a right-hand portion 48 connected with the thermostat terminal 38 and a left-hand portion 50 normally in spaced relationshipwith the thermostat terminal 42. An intermediate portion of the conductor 46 can be urged downwardly as illustrated by broken line 52 in FIG. 2 whereby to make contactbetween the exposed terminal 42 and the portion'50 and to complete a circuit in parallel with the thermostat 40. As best illustrated in FIG. 2, the intermediate portion of the spring metal conductor 46 is urged downwardly by manual depression of the translucent envelope 16, illustrated by broken line 54.

From the foregoing, it will be apparent that the heating cable 10 may be wrapped about a water pipe, the plug 26 insertedin a suitable receptacle for a supply of electrical power and the heating cable assembly will thereafter operate automatically to prevent freezing of water in apipe. The thermostat 40 will serve to energize the heating element 12 when ambient temperature drops below a predetermined level and to de-energize the heating element when the ambient temperature exceeds such level. When the thermostat closes the circuit to energize the heating element, it also energizes the indicator or pilot lamp 42 and an observer can readily determine visually the closed or operative condition of the thermostat. When the indicator or pilot light 42 is de-energized, the observer is advised of the open or inoperative condition of the thermostat. The conductors or leads 28, 30 for the indicator or pilot light 42 permit the orientation or positioning of the pilot light externally of insulation wrapping which may be placed about the heating cable 10 on a water pipe. This of course permits a convenient visual inspection of the heating cable assembly for operability.

In testing operation of the heating cable assembly, the plug 26 may be introduced to a convenient receptacle and the test device 46 may thereafter be manually depressed as indicated in FIG. 2 in the broken line condition whereby to engage the portion 50 of the test device with the exposed thennostat terminal 42. A parallel circuit is thus completed and the indicator light 42 will be energized to advise an observer as to the availability of electrical power. Further, the resistance elel2 toa terminal 38 on a thermostat 40. Thus, the resistance heating element 12 is connected in parallel with pilot or indicator means or lamp 42 within the translu- I claim:

I. An electrical heating cable assembly comprising:

a relatively thin, flexible heating cable including an elongated electrically conductive resistance heating element embedded in an elongated flexible insulator;

a thermostat electrically connected adjacent said heating element for controlling energization of the latter and having at least one exposed terminal;

visual indicating means comprising a small indicator light enclosed within a substantially translucent indicator envelope,

said visual indicating means being electrically connected to said thermostat and heating element and operable on closing of said thermostat for indicating energization of said heating element;

a test device electrically connected in parallel with said thermostat and operable manually to energize temporarily said heating element and indicating means,

and a substantially translucent envelope disposed about said thermostat and test device,

said test device comprising a movable metal conductor electrically connected at one end with one side of said thermostat and having its other end disposed adjacent said exposed terminal,

said other end of said conductor being normally spaced from said exposed terminal to open a circuit parallel with said thermostat,

and said other end of said conductor being urged into contact with said exposed terminal to complete said parallel circuit on the application of manual pressure to an intermediate portion of the conductor via said translucent envelope.

2. An electrical heating cable as set forth in claim 1 wherein;

said translucent envelope has at least one flexible wall disposed adjacent but in spaced relationship with said test device,

said wall being flexible inwardly on the application of manually applied pressure for operation of said test device as aforesaid.

3. An electrical heating cable as set forth in claim 1 wherein said conductor is of a spring metal construction and flexibly movable.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2696607 *Jul 16, 1952Dec 7, 1954Witkin Leon CCircuit control and indicator
US2752463 *Feb 3, 1955Jun 26, 1956Gen ElectricSwitch
US2824209 *Jul 20, 1956Feb 18, 1958Welcraft Products Co IncStrip heater
US2977456 *May 13, 1959Mar 28, 1961Stiebel Theodor HMiniature immersion heaters with watertight handles enclosing switching means
US3246112 *Apr 6, 1964Apr 12, 1966Donald R AdamsPolypropylene diaphragm assemblies
US3305668 *Aug 27, 1964Feb 21, 1967David C SmithCable heater
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4025755 *Nov 11, 1975May 24, 1977Wrap-On Company, Inc.Thermostatic electric cable heater
US4066870 *Dec 6, 1976Jan 3, 1978Bristol Products, Inc.Flexible electric heating cable
US4419569 *Mar 26, 1979Dec 6, 1983Bristol CorporationModular heating cable assembly
US4545375 *Jun 10, 1983Oct 8, 1985Aspen Laboratories, Inc.Electrosurgical instrument
US4650971 *Oct 24, 1983Mar 17, 1987Pgm, Inc.Energization indicator and method for heat trace cable and the like
US5920191 *Nov 12, 1997Jul 6, 1999Wrap-On Company, Inc.Current flow monitor for heating cables
US5933574 *Feb 9, 1998Aug 3, 1999Avansino; Gary L.Heated fluid conduit
US6072152 *Mar 17, 1997Jun 6, 2000Fleetheet LlcHeater control device
US7220947Sep 30, 2005May 22, 2007Global Heating Solutions, Inc.Pipe heater
US20050247480 *May 4, 2004Nov 10, 2005Schulz Steven MSelf winding electric cord
US20070075071 *Sep 30, 2005Apr 5, 2007Cardenas Carlos APipe heater
Classifications
U.S. Classification219/528, 340/655, 200/302.2, 219/506, 219/535
International ClassificationH01H9/02, H05B3/54, H05B3/56
Cooperative ClassificationH05B3/56, H01H9/0228
European ClassificationH05B3/56
Legal Events
DateCodeEventDescription
Sep 23, 1991ASAssignment
Owner name: EASY HEAT, INC. AN IN CORPORATION
Free format text: MERGER;ASSIGNOR:SMITH-GATES CORPORATION, THE, A CORPORATION OF DE;REEL/FRAME:005856/0339
Effective date: 19910328
Owner name: SMITH-GATES CORPORATION, THE
Free format text: MERGER;ASSIGNORS:SMITH-GATES CORPORATION, THE, A CORPORATION OF DE (MERGED INTO);HOLDINGATES, INC. (CHANGED TO);REEL/FRAME:005856/0328
Effective date: 19881229
Owner name: SMITH-GATES CORPORATION, THE A CORPORATION OF DE
Free format text: MERGER;ASSIGNORS:SMITH-GATES CORPORATION, THE, A CORPORATION OF DE (MERGED INTO);FEDERAL ACQUISITION CORP., A CORPORATION OF DE (CHANGED TO);REEL/FRAME:005856/0333
Effective date: 19890104
Sep 23, 1991AS03Merger
Owner name: EASY HEAT, INC. AN IN CORPORATION
Owner name: SMITH-GATES CORPORATION, THE, A CORPORATION OF DE
Effective date: 19910328