Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS1443786 A
Publication typeGrant
Publication dateJan 30, 1923
Filing dateMar 26, 1921
Priority dateMar 26, 1921
Publication numberUS 1443786 A, US 1443786A, US-A-1443786, US1443786 A, US1443786A
InventorsDolph Norman L
Original AssigneeDolph Norman L
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Transformer temperature indicator
US 1443786 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Jan. 30, 1923.

' N. L. DOLPH.


FILED MAR-26. 1921- Quorum Patented Jan. 30, 1923.


Application filed March 26, 1921.

T 0 all to 710m it may concern Be it known that I, NORMAN L. DoL-rH, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented a certain new and useful Improvement in Transformer Temperature Indicators, and declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification. I

This invention relates to temperature indicators or trouble signals, especially adapted for use in transformers or similar electrical apparatus, whose load capacity is limited by a certain known maximum of operating temperature. My improved device is especially designed to obviate the necessity of close inspection of the individual transformers, some of which are often located upon poles or side walls fifteen or twenty feet above the ground or fioor level, and which it would be inconvenient to approach closely and frequently, to ascertain whether or not the transformer is overheating. My invention, which has nothing to do with the details of the transformer from an electrical standpoint, is essentially an adjunct, which may be employed either to operate a fixed mechanical signal, whose variance from normal position as regards its signalling, when the transformer is overheated, may be easily observed from a distance, or to close an elec-' In the drawings, Figure 1 is an elevational view of my device, shown partly in section with respect to the adjoining wall of the transformer box;

Figure 2 is a sectional elevational View along the line 22 of Fig. 1, looking in the direction of the arrows;

Figure 3 is a similar sectional view taken on line 33 of Figure 1;

Figure 4- is a similar sectional view taken on line 4.& of Figure 1;

Figure 5 is a perspective of my improved device in place'on a fragmentary section of the transformer wall, showing in dotted lines the position of the trouble or alarm in- Serial No. 455,870.

dicator when the over-heating of the trans former has caused it to act; and

Figure 6 shows the application of my signal members to the closing of a circuit. I

A indicates the wall of a transformer box,

into a screw-threaded aperture in which the smaller diametered tube or stem E,

whose outer end projects sufliciently beyonc the outer end of the tube D so that it may carry the screen-piece G in a position to nor- .mally blank or conceal the trouble-indicating member F, and whose observable surface 18 preferably of a different color, and so that when functioning the two pieces F and G lie.

in closely parallel planes.

Engaging about thecylinder D is a helical spring H, one end of which is anchored to the outer surfaces of D, as at J, while the other end is similarly attached to an anchoring screw K which projects through the slot L into the body of the inner stem piece E.

7 As brought out in Figs. 1, 3 and 4 particularly, the adjacentv ends of the cylinder D and of the stem E are cut away in what might be described as an L-shape, and when they have been rotated relatively to one another so that the trouble indicator piece is blanked by the screen G and the spring H sion, the cut-away portions ofthe ends of the cylinder D and of the stem E, asM and N, are located diametrically opposite to one another in such a way as toleave a key-way or slight space between them. This space is then filled, and'the two parts lockedsinpo has been drawn to the desired degree of tensition relatively to one another, by the in- I sertion of an easily'fusible plug or key Q, whose composition, by the use of desired proportions of such well-known elements as lead tin bismuth and cadmlum or other fair equivalents, may be regulated as desired with regard to its fusing or melting point. As long as the alloy within the transformer casing is not heated by the contained oil to or above this point, it remains in place. and

tunctions to prevent relative rotative movement of the two parts l) and a under pull oi thespring' H. is soon as the tc-mpe 'ature of the oil has risen to the pointat which "tusing or melting of this plug or key takes place, however, it no longer operates to hold the cylinder D and stem E against rotation, and the pull of the spring llupon the inner tube or stem E while the outer tube l) remains anchored against rotation by reason of its positioning in the wall It, results in the retation of the stem E and its supported screw (1, as-regarcs the common axis ot the cylinder D and stem E; thus uncovm'ir the indicator F and rendering it easily observable to an inspector, who an at once climb up to the box and make such changes as are necessary in the electrical apparatus. So long, however, as the trouble indicator l concealed by the screen (i, he needs only to glance at it in passing.

When the trouble with the electrical. appaatus has been remedied, the inspector removes the trouble indicator mechanism just described, as unit, by unscrewing, and either puts in its place an indicator piece with a :tresh fusible plug or key Q, else, atter winding up the cylinder D relatively to the stem E until the spring H is of the proper tension and putting in a new key Q, he is able to make use of the same signalling apparatus.

In order to prevent the material ot the plug or key when melted t'rom tailing against and hardening in the inaccessible inner end of the container l5, thus rendering it worthless for future re-use, l preterably employ a cap or thiinble piece l, which fits; over the cut-away end p0 tions of the tube l) and stem and key Q, and which thus catches the fused or molt-en mass and prevents it trom falling into the fried containing cylinder In Figure 6, l have shown a slightly modified form of construction, which employs the same parts as regards the relatively rotatable parts D and E nornia ll y held against pull of the spring by a fusibleplus, but which substitutes for the indicator l* and its screen it the swing; of the lever 55, when the t'usible plug gives way, so as to engage the terminal T of the otherwise open circuit V and thus actuate the alarm bell 51; so long as the fusible plugholds, the lever 53 is in the position shown in do ted lines.

What I claim is:

1. An indicator, 0 n with a pair of coaXially disposed signabsi porting members, resilient means for intatively actuating one of said members rela tively to the other, to effect an observable change in tie relative positions of signal. pieces carried by each, and a t'usible lock ing member adapted to normally hold said signal-supporting members in tensioning to perm position. relatively to said re Z ient rotating; means, and upon melting, due to the attainment ot a predetermined ten perat-ure,

' he spring to actuate said signalsuppoitin o members as described.

2. in an indicator, the combination of a. pair of coz Xially disposed signail-supporting members, each ot which is provided its end with a; observable signal piece, a spring member adapted to actuate one of said members relatively to the other. thereby eltecting a change in the position of its signal piece relatively to the other, and a fusible .ieppiece serving to .iold said 10- arcially dispose i in o posiier until u members in strait tion. as reg irds said spring meni the surrounding temperature hair i :Xlllfifl melting degree, then and thereby allowing the spring to rotat'vely actuate one of said coaxially disposed members relatively to the other. i

3. An indicator, liaving in combination with an outer tubular member, a co-axially disposed stein member rotatably disposed therewithin, a spring with the ends of which said tubular membe ant. said stem n'ieinber respectively connected, a tnsible keypiece adapted to lock said stem member relatively to said tubular member in distorting position relatively to said springnntil a predetermined temperature has bee: attained, and a normally screened sie nal member adapted to be uncovered by th 1 tation of said stein relatively to said tubular member upon its rotative response to pull of said sprin, when the melting: of tusible l'ey takes place.

4. in combination with a tubular member, a stem member rotativel engaging therewith and operatively coimected with a normally inactive external sig l. a spring member connected with said tubular member and said stem member and normally held in torsionally strained condition by the relative position. thereof, and. a tusible herpiece for holding;- said stem member against rotation relatively to said tubular member until a predetermined temperature has been attained.

5. The combina ion, with a tubular meni ber, ot a stem member retatablv movable there vithin, observable signal pie supported by each of said members, a spring: member adapted to be held in condition of tension by and during the normal position ingof said stein relatively to said tubular member, and a member of low t1 sibility adapted to ho d said members in such position during the prevalence 0t interior thermal conditions tliereabout, said stem menn her and its supported signal piece being adapted to be moved relatively to the tubular mem. er and its signal piece by the ac tion of said spring member upon the yielding ot said holding member, due to its attainment of a melting degree of temperature.

6. In combination With a fluid-containing member, a plurally-membered device adapt ed to engage therein, consisting of a pair of relatively movable and coaxially disposed members, each of which carries an externally observable signal piece, thermally responsive element for normally locking them in inactive relative position, and a springmember held in'a condition of tension while said coaxially disposed members remain in inactive relative position, adapted to actuate one of said members rotatively vith respect to the other'upon their release due to the giving Way of said thermally responsive element, thereby effecting an observable change in the position of one of the signal pieces relatively to the other.

7. In combination with a pair of rela tively movable members, externally observable signal pieces of accordingly changeable position supported thereby, a locking member of inferior thermal character for normally preventing relative movement of one of said members with respect to the other, a spring member so connected with each of said movable members as to be held in torsionally strained position while said memhere are held by said locking member in normally inactive position, and means for subjecting said locking member to the changes in the thermal conditions whose variations are to be watched, whereby upon the attainment of a predetermined degree 01"? temperature the action of said locking member upon said relatively movable members is terminated, thereby permitting said spring member to effect an observable change in the relative position of their exposed parts.

8. In a safety device for oil-cooled transformers, the combination with a container adapted to be positioned in a circulation of cooling oil, of a stem member and an observable signal carried thereby rotatably contained therein, a spring member operatively connected with said members and under torsional strain while said members are in normal position relatively to one another, and a thermally fusible locking key normally serving to lock said members in such position, adapted to give way upon the attainment of a predetermined temperature communicated to it from the oil, thereby permitting the spring to cause an observable change in the position of said stem member and its supported signal.

9. In a safety device for oil-cooled transformers, the combination, with a container adapted to be positioned in the circulation of coolin oil, of a separable device extendinginto said container and comprising a relatively movable member, a temperaturecontrolled element normally holding said movable member against movement, a spring operatively connected with the parts of said separable device and adapted to actuate said movabl member upon the i'ces sation. of the holding action of said temperature controlled-element, due tothe in creased temperature imparted to it by the surrounding oil,-and an'observal)le signal piece carried by said relatively movable member; i

1 10. An indicating device for transformers, comprising a heat-conducting container adapted to project into a heat-generating locality in, said transformer, a movable member in maid container, an observable signal piece carried thereby and means responsive to temperature changes within said container, for normally holding said movable member against movement and for releasing the same upon a predetermined rise in temperature, and spring means for actuating one of said members relatively to the other after said holding member has ceased to function, thereby eftecting an observable change in the relative position of said mov able member relatively to the container.

11. An indicating device for transformers comprising a heat-conducting container adapted to project into a heat-generating locality in said transformer, a shaftprovided with an observable outer end portion, projecting into said transformer, thermally responsive means for locking said parts against relative rotative movement, and a spring member held in torsionally strained position While said first-named members are in normal position, adapted to rotatively actuate said shaft upon the cessation of thelocking action oi": said thermally responsive means. 1

12. In combination with a heat-conducting container adapted to project into a circulation of cooling fluid, a cylinder removably supported in said container, a stem rotatably positioned within said cylinder, an observable signal piece supported thereby,

fusible locking means adapted to normally hold said stem against movement with respect to said cylinder, and a spring member adapted to rotatively actuate said stem member'and consequently effect a change in the position of its supported signal upon the giving Way of said fusible locking means.

13. The combination of a, fluid-holding member, a heat-conducting container projecting into the interior of said fluid-holdcontact therewith, a stem rotatably disposed within said cylinder, a spring connected at its ends with said cylinder and said stem mg member, a cylinder removably support ed in said container and adapted to make respectively, a fusible'link adapted to normally hold said stem against movement relatively to said cylinder and to hold the spring ing said stem against movement relatively to said cylinder: and a spring' adapted to act upon said stem upon its release due to the softer' '1' of said locking: key, for actuating); Said ,Stfilfl relatively to said cylinder, thereby effecting: a change in the position of the observable end portion thereof.

In testimony whereof I sign this specification in the presence of two Witnesses.


Vitnesses WILLIAM M. SWAN, Jnrrnnsox G. TI-IUnnnn.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2477571 *May 21, 1948Aug 2, 1949Billman Richard MHot box indicator
US2479468 *Jan 17, 1947Aug 16, 1949Line Material CoOverload indicator
US3052876 *Oct 8, 1959Sep 4, 1962Brown Robert MIndicating device for meat treatment
US3656452 *Jun 15, 1970Apr 18, 1972Dun Rite Mfg CorpTemperature signaling device
US4060381 *May 3, 1976Nov 29, 1977Evenheat Kiln, Inc.Shield for pyrometric cones used in ceramic firing kilns
US4080567 *Jun 9, 1975Mar 21, 1978Duncan Electric Company, Inc.Heat sensitive abnormal condition detecting and indicating device and method
US4563973 *Jul 12, 1984Jan 14, 1986Stull Dean PHeat detection apparatus
US5487352 *Sep 21, 1994Jan 30, 1996John R. WilliamsTemperature indicator for cooked meats
U.S. Classification116/218, 340/590, 340/646
International ClassificationH01H37/76, H01H37/00
Cooperative ClassificationH01H37/76
European ClassificationH01H37/76