US1868136A - Temperature responsive device - Google Patents

Description

J. H. DERBY 1,868,136

TEMPERATURE RESPONSIVE DEVICE July 19,`1932.

Filed Mayle. 19:50 2 sheets-sheet 1 July 19, 1932. L H, DERBY 1,868,136

TEMPERATURE RESPONSIVE DEVICE Filed May 16, 1930 2 Sheets-Sheet 2 Patented July 19, 1932 meer *eme-E AJoint fir. 'umani oi` scsnsnatn, NEW Youn, Assienon'ro AMERICAN Finn runnen- Tion suenan, ornnw Younis, YQ, A

i Application filed May 16,

This invention relates to a temperature re'- `sponsive devicefor closinga circuit when `a zgiven temperature is reached'and particularly to a device having a fusible conductor between circuitterminals, but normally inv p edges and over the annular insulating blocks sul'ated-from atleast one 'of the terminals. In the .earlier patent granted to myself and AErnest S. Clayton, No.V 1,274,248,1 and April -11 w28/,aradisclosed and claimed devicesintended for' a similar purpose, The device asconstructed :according to my said in my application Serial No, 269,076, ,filed patent hasproved extremelyefficient and satisfactoryior guarding against excessive temperatures: and particularly for giving .alarm in 'case' of or incase of excessive Atemperatures Whiclimightglead to fire.' However, itis necessary to Vuse great care in the manufacture of these devices ingorderto -f'fgeavoid `cold flow of the fusible conductor which might eventually closethe circuit although the temperature had not exceeded Ythe given limit. Although this objection has iot interfered Awith the usefulness oit my earlier invention it is desirable to provide a more positive means forpreventiug the cold -llow 'lof the fusible conductor., lt, is accordingly an object of my invention to provide a temperature vresponsive deviceiin which `thecold eo-flow' of the 4fusible element is substantially avoided, `and/or rendered unobjectionable. OtherObJeCtsOi" my invention will be readily apparent romgthe ac companymg` description.- f

1135 f In the aCcompanying/drawings .,Fie'urel shows a cross sectionA of a .preferred embodiment; y f Figure 2 shows a bottom elevation; ',flligure 3 sliriu'sL a partial cross section nrfniliiication;V Figures@ shows across 'section .through-anfother niodiiicati'omand Figures nand 6 shew'` partial cross sections of other embodiments.

- Referring particularly to `Figures land 2,

the' device isi'ormedwrith a metallic casing preferably ofv-Monel metal comprising abottorn section 10 and atop section llinsulated from eachy other by the annular blocks, 12 and i150 13 which are `advantageeusly made of a phelock the device in its oonrona'ri'on or mwa-onli 4`TEMPERMunn .ansronsivn DEVICE '1930. t serial No. 452,595!

vice is designed to operate;

The bottom portion 1 0 is bent up at its v 12 and 13 soas to clamptthem in place.and assembled relation. ANearthe `center thebottoin section 10 is formed with a Well 14 in which iscemented an annular ring 15 of suitable insulating material, advantageouslyA infusible phenol iprmaldehydey resin. Within `the' Well disk of; fusibleV alloy `1.6 is positioned and V above this is a diskl? of insulating material advantageouslyinfusible phenol formaldehyde, resin or `varnished oambric. Above .this -Aand vstill partially Within the `Well formed by'thering lis a button v18 suitably loiflllonel metal or other.corrosion-resisting conductor. T This button 18 isin electrical centactvvithithe vupper section l1 of the caslngfand-isheld in centered relation thereto by a pin'lQ which projects through a :hole V2O in tlresection 11. The thickness of the button 18, the insulating disk 17 and the vfusible disk 16. and theshape `ofthe section 11 and the -section 1Q are such as to cause l 11 tending to return to their normal shape, there will still remain nat least a thin film of the fused conductor 16 to form a more perfect ContactA Vwith lthe bottom 10.

As Vbetter illustrated in Figures 2 and 4,

thek sections lO and 11 arel extended on op-v positasidesto form; ears 21, 22, 28 `andfQl 4for connection togbinding postsV orin other suitable manner tothe conductors Otan electricalA circuit.

ln theembodiment illustrated in Figure 1the fusible disk,16 islaterally conlinedV by thevertical Wall of the ring and thus cold i conductor 16 is fused andsqueezed out embodiment of casing might beused approximately 1.593 in outside diameter and approximately .145V

button 18 is such as to permit flow of the material is substantially prevented.

For greater clearness of illustration the parts have been shown in somewhat exag gerated proportion on the drawings. In an my invention a yMonel metal inch thick. In this case the ring 15 is cemented into the bottom of the well 14 and a Vfusible solder disk Vapproximately .015 inch in thickness is fitted closely inside the bakelite ring, and contacts with the casing 10 at the bottom of the ywell 14. The disk 17 may be made of bakelite or other phenol formaldehyde resin or resin compound or may be made of a varnished cambric and it may be of a thickness between about .O20 and .O31 inch. These figures are not the limits of satisfactory operation but are merely thedimensions used in the preferred embodiment. The metallic button is of a thickness related to the shape of the casing so that when the casing is assembled as shown, it will be deformed about .015 inch from its normal shape and will thusexert a constant tension upon the fusible disk 16. The clearance between the peripheraly edges of the insulating disk 17 and the' metallic ready flow of the fused conductor into Vcontact with the metallic button 18 and to avoid any binding of these elements on the sides of the ring 15. It should, however, be sufficiently narrow to assure the fused conductor rising high enough in the space to effect a good electrical contact with the metallic button 18. The disks 12 and 13 in this embodiment are approximately 3/64 of an inch thick and are made of bakelite or other similar phenol formaldehyde condensation product or comn position thereof.

The sections 10 and 11 may advantageously be die-pressed from sheet metal, the parts then assembled with the ring 15 cemented to the lower section 10 and the edges of the lower section 10 of the casing may then be turned over the rings 12 and 13 in order to clamp the parts in their assembled relation.

vThe whole is then advantageously covered such, for example,

with a waterproof varnish similar asv a phenol formaldehyde or other resinous varnish.

In the embodiment illustrated in Figures 4 and 6 the pressure element (the button 18 in Figures 3 and 6) is recessed as at' 26 lcentrally above the insulation and the in*- sulation used should in these cases advantageously be flexible. This recess is preferably about .005 inch in depth, its purpose being primarily to relieve the pressure on the fusible conductor about the point of perforation through the insulation.y They depth of the recess should, however, be sufciently small vso that the fused conductor in passing Ywith the walls of the well,A

through the 'perforations will contact with the terminal at the top of the recess. The width of the recess should be` at least double the width of` the annular bearing surface which surrounds it. In these cases also one or more centrally positioned. openings 27 through the insulation are provided. In these embodiments the pressure resulting from the deformation of the casing is applied to the fusible disk over an annular area. Such cold flow as Vresults is accommodated by the central recess, the flexible insulation lifts if Ythe fusible material bulges centrally due to the cold flow and the whole rises into the recess 26. Thus the flow of'material into the opening` through the insulating Inaterial is avoided and the device is thus protected against the giving of false alarms due to cold flow. y

.In the modication illustrated in Figure 5,

the insulating disk 17 is molded or fittedl on the face of the metallic button 18 and extends slightly `beyond the edges thereof. This extending rim ofthe insulation serves to hold the button 18 against moving into contact which in this case are not protected by the ring 15. If any cold flow should occur the cold metal couldgnot How back over the projecting rim of insulation vand therefore could not contact with the button 18. I have illustrated in Figure 5 an embodiment of my invention in which the well is formed entirely by the bottom 10. I find it more advantageous, however, to use the ring 15 since in this way a sharper corner and a more nearly perpendicular side may be made and thus any deflecting of the cold thoroughly voperation by which the section 10 is formed.

In Figure 6 I have illustrated another modification of the device. In this embodiment the'V insulating ring 13 is extended in close to the center so that its inner face delines the upper part of the well- The Vlower part of the well may be'defined by a depression 14 formed in the bottom'lOV as illustrated, or the bottom may be made perfectly flat and the insulating ring 13 be made of sufficient thickness to providethe required depth in the well. tageous to cement the ring 13 to the bottom 10 inrorder to prevent any loss of the fused conductor between the insulator 13 and the bottom 10. t

Although I have shown the recess in Figures 3, 4 and 6 in the pressure button 18, the insulation 17 or the fusible metal 16 may be recessed instead. The important thing is to relieve the pressure on the fusible metal adjacent the openings 27. Instead of the above In'either case it is advan.

the part `14 ef the bet-tem 1o whiehferms lthe Ybottom of the well may be dished slightly so ibleelement is confined byithe 'ring 15 and/or is accommodated in the'recess '26. However, as soon asY the fusion point -is reached the fusible element 16 becomes fluid and readily flows into the narrow space between thevldisk 17 and the ring 15 or through the opening 27 and `overthe top of the disk 17 into contact with the button 18. The result of-this is the closing of the circuit `through the sections 10 and ll and the automatic operation thereby of a suitable alarmor of any other de sired electrical device.

Although I have illustrated in the accompanying drawings and described above a preferred embodiment and a number of modifications thereof, it will be understood that my invention is not limited to these butthat many other changes and modifications may be madewithin the scope of my'invention.

Although I have referred above and inthe accompanying claims to a button `18, it is to be understood that I do not intend by this term to be limited to a button separate from the top 11, or other forms of circuit terminal with which it may be associated, but, on the contrary, the button thus referred to may be an integral part of the top 11 and/orthe circuit terminal as, for example, in the embodiment illustrated in Figure 4.

I have used the term floating disc in the accompanying claims to define a disc which is free to move within the well Without flexing,-2-for example, a disc such as that shown at 17 in Figs. 1, 3, 5 and 6, as distinguished from the. insulating disc 17 of lFig. 4.

What is claimed as new is:

l. A temperature responsive device for closing an electrical circuit when a given temperature is reached Vwhich comprises a circuit terminal having a well thereon, a conductor adapted to fuse at the given temperature mounted in said well so that in its fused condition itv will contact with said circuit terf minal, a layer of insulating material substantially covering said fusible conductor but leaving a small space through which the conductor may, when fused, flow past said insulating layer, a second circuit terminal resiliently pressed against the insulating layer and toward the fusible conductor whereby to force the latter, when fused, through said space and into Contact with said second circuit terminal, the second circuit terminal being recessed about said space whereby to avoid contact between the fusible conductor and the second circuit terminal in case of cold flow of the fusible conductor.

2. VA Yftemperature. responsive i device :fer -elosinganelectrical circuit when ag'iventem when fused it will bein-centaetwith-said eir-l fcuit terminah-fa'disl-of insulating material fitted in said well butadfapted t'ovp'ermit` a `substantial'stream oflthe fusible conductor when fused to escape pustit, meansfor maintaining a resilient'pressure en said 'disk` against sai-d -fusibleconduc'tor, vand avsecoild l 4circuit terminal mounted so as to contact with the fused conductor when it escapespast the insulating disk. a

3. A temperature responsive deviee'fffor closing an electrical `circuit when a given temperature is reached, which comprises'acir- Acuit Yterminal having a well thereon so 'that a contact portion is `within said 'vv"ell,-acon` ductor adapted to fuse at the giventemperature mounted in'said''well-so,thatwhen` fused, it will be in electrical contact vwith thefcir- `cuit terminal, and a floating disc'in said well of a diameter'to'leave suflicientclearancebetween its edge and the sides of the-wll Vto permit freemovement of'said disc in the r4Well when the fusible conductor is fused, means for pressing the discagainst said' fused conductor so as to cause thelatterfwhenit is fused, to iiow past'v thedi'sc,` vand a-second circuit terminal Contact portieri'V electrically insulated from theI first circuit terminal',fbut positioned near'the fusible conductorin said well so as to makeelectrical contactwith the fused conductor which escapespastsa-id disc.

4. A temperature responsive device as delined in claim 3, in which the well `is designed to limit cold flow of thegfusible conductor.V

5. "A temperature responsive'device as-de- `finedin claim 1, in -whch't-he resilient lpressure of the second circuit-terminalfis 'such "that it will/not move the insulating layer .toward the4 rst circuit terminal fartherffthan `willlea-ve a substantial layer-'of `thefzfusid conductor therebetween.

f' 6.`-A Vtemperature 'responsive device as de-l lfined'in claim Sin whichfthesurface bf the `second circuit terminal isset back fronithe corresponding surfaceof l'fthe disk ladiacent Y the spaceithroi-igh` which thefusible metall :is to flow soas to `avoidelectrical#Contact between `said circuit terminal land t-he'fl`1sib`le conductor bv celdnow of the latter.-

" 7.A temperature responsive deviceffo'r closingfan electricalcircuit when a' lgiventemperatureisreached which' comprises a pair of circuit terminals, a conductor-adaptedjto fuset at :the given-temperature mounted-en 'one circuit terminal vso as'to bein electrical contact therewith when fused and-'confined so that, when'fused,"it` is free*toff'ivv' only l So-as to contact withthe Vother circuitlten minal, insulating means separatingthe'fusic -andhaving a depression .tor may swell the central par yble conductor from the second terminal but .having centrally disposed openings therethrough to permit escape of said conductor,

when fused, into Contact withthe seco-nd tei minal, said second terminal being' resiliently 4pressed against saidinsulating means toward said fusible conductor over an annular area surrounding said centrally disposed opening adjacent said openthe fusible ,cond-uct of the fusible conductor without causing itto flow into coning whereby ycold flow v of tact with the second circuit terminal.

8. In a t-herinostatic .circuit closer, a circuit terminal, a disk of conducting material fusible at the desired temperature of operation ofthe thermostat and having one face bearing against said terminal, insulation peripherally confining said disk, other insulation bearing against the remote face of said temperature of operation of the thermostat rest-ing upon said circuit terminal. and confined by the sides of said well, a second circuit terminal comprising button extending .intoz saidwell and having sufficient clearance therefrom to be freely movable thc-win and insulation pressed by said button aga nst said fusible disk and `periplierally s iced from the sides of said wall.

10. A thermostatic circuit closer comprising a circuit terminal having one face` ex- Osed 1 for receiving the oneratino' heat a' 2D .L t3 7 disk ofaconducting material fusible at the desired operating temperature bearing against `the other face of said terminal, insulation closely confining said disk above the circuit terminal Yand foimingfa well thereabove, a second circuit terminal comprising a.- button extending into said well and having sufficient clearance therefrom to be freely movable therein and insulation pressed by said button against said fusible disk and peripherally spaced from the 11. A thermostatic circuit closercomprising a disk'of conducting material fusible at thev desired operating temperature, a circuit terminal having. one face exposed-to the Operating heat and the vother face in engage ment with said disk, rigid insulation peripherally confining saidv disk and forming I a guide extending beyond the other face of said disk, a second circuit terminal movable within .said guideand having its face insulated .from the face of saiddisk, said circuit ininals, said parts being adapted and related sidesv of said well.

terminals being so pressed toward and insulated from .each other that said disk ismaintained under compression, space being provided in the insulation between the last mentioned terminal and the fusible disk for flow of conducting material into circuit closing Contact with said terminal when said disk is fused. Y l

12. A temperature responsive device comprising a pair of circuit terminals resiliently pressed toward each other, onek of said terminals having thereover means for laterally confining a fusible conductor when fused, a fusible conductorbetween said terminals and within said confining means, means for insu-` lating one of said terminals from the other and from the .fusible conductor adapted to permit said conductor, when fused, to flow into circuit-closing Contact between said terso as to prevent cold lflow of the fusible con ductor into circuit closing contact.

13.A device as ldefined in claim 12 in which the insulating means has a central opening therethrough adapted to permit flow of the fused conductor into contact with second conductor, and one'of the enumerated members is recessed over an area surrounding said opening so as substantially to relieve the fusible conductor adjacent the opening from pressure exerted upon the fusible conductor.

lfl. A device as defined in claim 12 in which the means for preventing cold flow comprises an annular ring surroundingtlie. fusible conductor andhaving its inner wall substantially perpendicular tothe plane of the normal cold flow of said conductor.

'Signed at New York, N. Y.,this12th day of May, 1930'.

JOHN iLnnRBY.

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