US2049193A - Thermally actuated apparatus - Google Patents

Description

July 28, 1936. A G L N 2,049,193

THERMALLY ACTUATED APPARATUS Filed Aug. 12, 1955 2 SheetsSheet 1 Q a flit/Mr George Bullen. m Kfifi [Jul 28,, 1936. A. GJBULLEN 2,049,193

THERMALLY ACTUATED APPARATUS Hi, ttarneg.

Patented July 28, 1936 Appmunn mc 12; nmasiassa':

August 19, 1932 This imzentiom reiaflesftof anpamus; empioymz aub w: and: the like, which memtwapp'or: ex-- traction of heat undergo'i are: appliemwiotfen" l movement olt'metal';v ole m uh.- staacesr associated mum-ream mtm'tsnce mntisiintvan'dmi tdymil: fliiibie the, tbl'iomngfichmwfismr dependent. upon the qunntm at: cnnizliefl'hlw viz: hardeni'naro: of matiwpliertorextracmmia pa'med? by mmpe'nmnewthemb o'r' cthemse; mom, *3 viscosity, volumetric sionsi' on condensation anmcei physical; m the purposew'f convenience, mm

I be? consideredias ing the imventiomi'whm'helt eratiun'smiiitbe reversea asfiisiz.

In panticuiarthisimenmix into eflect some of scribed in my. specification 318,586; some of-the wax caa'tridgeshc: with) the present invention; to' intemeiin ge tliese' cartridges and: permit" adjustments; at mon; to enable the'associate'di-mmarmdaw in be reset aiter eacmactuatibn; meme methndsi otc actuation not i e'stnicibd" ing efiect' 01" an] electrie the wax cartridge included imthe pnexlimls tion. For: example; iwhflerthe p r'esnnt 'inmon 1 is intended: -a,s'a-'protective "dnice m1! We! apparatus primarily; emf-as" such rmwmainlt take the of a switch to or conductor circuit;- it nis not imiendedxco reati ict its: application to switchgearommeana to inimruptz circuits, its:use-'mm'be appiied co other-2pm:-

poses where thermal: contmi '01: "ac' is. required; Asia thermally'operated apparams for tection ofelecbrical planty-my mmmmPmme tended. tokbe"actuated by excesive -riee temperaizune' of" the electrical plant Mid in mm, invention. is intended actuate: apparatus intended toi deal with such excessive rl'peot tamperature which may rewirin gxbreakdidw ifofi' 1 the saidplant, in: addition no giving wminw'that the said plant; requires: attentiom For example'my-inventiommy be MtIIMEdFIby theheating efl'ect otian excess curmnt'canied by its associated wex'carmdge; but in r heavy loads. are. carnieckfor shortit may" be ptimevictimtic-actuatev muexxtion'uummme otf'thmbhort. enudfmeds; beineiexceeded.

ae 'watez heing inimm imi mcientiy cooled heicizea m-emmaummiewmnspneme temper- 1-0 ccnditinns. the bearihfof mnn'inv thaa pram; overheucfdue to xdcfochron-aemz mm oil mane-m I I u v o fsystemait'may not 'be deairdbie to I running; New; but: to mve waming 'and 5 suppleliientmry" oil in:P1 13?will!!! ly t'o:other timn eiectrical 'saidzitwentiomis imded fbr 4 lceuudiagw thiflnirenticma contgnwr 18 pmwiie df 'wim a snbstance anew mechanical but 'lat'b'em is mama: hy heat 2 'aaplie, 121w the combiner mechanical-member me such mcmmentxsor ialtemztidn utilized rcn acmating The accompanying-i drawings shew diagrami some; embbdimcnts ofi thisitivention in jwhibltu I 1 Figs I" shows-"mu immnizimra'rpolieci tom three muicrifoz-trippmgeae main swifich. h 7

- w isf'a. mm elevation pi a 'swibchwifih 5 1 applied" to the circuit shown in 2,2 is'a-zsactionali elevation OfezcdmWeSsidn type of switch. I

" is'msectiom elevation-0F mobhenorm E193 41mm sectional elevation a. can m w m J i Fig: Elis a? ei'evatibriof a. furthm modl flication. I i 1 HELIGHSRM! eievatim at rightr angles" .te mg; 5'.

Fig; showsa still further-- modification of switch W catch or locking device.

tained in the cartridge when the latter has not reached the operating temperature. When the operating temperature is reached, the suppleg,

menting resistance of the wax to the movement of its associated helical spring becomes irisufli cient to resist the force tending to actuate the switch, this actuating force then predominates and the switch is actuated.

As an example:A contact is supported on a moving arm and against the action of a retractive spring, said arm is moved forward until its contact meets a fixedcontact. The arm is retained in position by meansof a trigger or catch mechanism which may take the form of a lever upon whichjismounted a contact arranged as a If the retaining means is of a lever type, one end is secured to a locating .terminal block so arranged that the moving arm ,when moved to the normal position, raises the lever ,irom thelocating terminal block .untilthe catch mechanism is engaged. The opposite end ,Of the lever is secured to awax cartridge terminal cap, hereinafter described which may be raised or depressed, when thewax within the cartridge softens due to the circuit current passing from the, spring within the cartridge, its terminal cap and lever to the moving arm. The retractive force tending toactuate the moving arm and thereby the circuitcontrolled, tends to raise or lower the cap fitted to the cartridge, due to the arrangementof the lever; When the wax softens in the cartridge sufiiciently to permit the lever to move the cap, the catch mechanism is released, the moving arm ,actuatesthe circuit, and the force exerted previously onthe cartridge cap being released, the latter returns to its normal position because of its inherent tension .unrestrained by the softened wax, in this position the wax cools and hardens when the switch operation may be repeated indefinitely.

The cartridge may be carriedby a moving arm or occupy a fixed position according to the type of switch required, or itself may constitute the moving-switch contact or contact support in which case the cartridge cap would constitute one contact and the lower end of the cartridge would be hinged to permit the circuit opening contacts to move apart, due to the pressure of springs, gravity or the like.

The lever action will not be required in all types of switches, but has an important application in cases where contact pressure is important and the mechanical strength of the spring within the cartridge is insufficient to directly enable this pressure to be effected. Further, since the adjustment of pressure or lift, at the cartridge cap due to the retractive force on the switch moving parts being applied through a lever arrangement, it is possible to further calibrate the apparatus employing the cartridge, since the degree of softness of the wax associated with the spring will influence the point at which the retractive force can operate the switch mechanism, adjustment of leverage proportions enables individual cartridges to be further calibrated.

This invention may be used in combination with apparatus of a known kind, for example, with coil operated overload switches to which it may provide the time lag features. The mechanical arrangements described are principally intended for application with wax and the like substances which are insulators of electricity, but the invention is not restricted to such, should it be desired to actuate the apparatus described by other types of thermal elements, metal alloys,

: bimetal strips and the like.

Referring to Fig. 1 two switches I and 2 are provided for controlling a main switch 3 in a three phase circuit A, B, C, connected to an electric motor 4. The thermal elements of the switches I and 2 are in series with the main currentcircuit of phases A and C between the main ..'switch land motor 4, the middle phase wire B passes direct to the electric motor 4.

A trip or shunt coil 5 is connected across the .two phases Aand C in such a manner that if either of the switches l or 2 is operated the trip coil circuit is interrupted and then the main switch as herein set forth.

...- The switches land 2 each consist of a metallic container 6 which are connected in series with the respective phases A and C as shown in Fig. 1, being supported in an insulated mounting 6 (only one shown). A helical spring I having the upper coils of ,a smaller diameter than the lower ones has the lower end 8 fixed to the base of the container 6. The containers 6 are partly filled with a wax substance, so that when thewax substance is solid the larger coils are embedded therein. The advantages of providing a spring with the upper coils of smaller diameter, than the lower coils, is that, the mechanical strength of the smallercoils are greater than the larger coils, further the smaller convolutions will cut their way through any wax that has risen in the container. The upper end of the spring is fixed to a rocking lever! with contact 9, which in turn, is f loosely supported upon a rod I0 fixed in the insulated mounting B. The movement of said rockinglever 9 upon the'rod I0 is limited in one direction, by means of a collar ll fixed to the rod l0, and in the opposite direction by a helical spring l2 arranged on the rod II] in a recess in the mounting 6 and a stop 9 as shown in Fig. 1, whereby the rocking lever 9 is free to move when the wax is solid in order to close the circuit.

A pivoted switch arm I3 is adapted to engage with, the rocking lever 9 against tension of a helical spring I4 when the circuit is closed, and a spring controlled plunger 9 is adapted to open the circuit when thewax is solid.

The operation of the switch is as follows:-

The switch arms I3 are first closed and the motor is then started up in the usual manner. Assuming the main circuit requires fifty amperes per phase the trip coil may only require one ampere, should there be an excess of over fifty amperes in any one phase, one of the metal containers are heated causing the wax to soften or melt and release the trip coil switch, if there is more than one ampere in the trip coil circuit, then the helical spring is heated, causing the wax to soften or melt, thereby releasing the trip coil and the main switch.

The content 9 can either be depressed automatically through the softening or melting of the wax or by hand. In the automatic operation, the pressure of the contact l3 acting upon the contact S'Hthrough the tension of the spring [4 is unable to compress the spring l2 which latter, is purposely made stronger. The pressure of contact |3 on contact 9 also tends to raise the end of the rocking lever 9 at the opposite end to the contact'Sl' by stretching the spring 1', which is prevented when the wax is solid. When the waxsoftens the spring I lifts, the smaller diameter of the coils cutting their way through any wax that has risen in the container 5, the rocking lever 9 is tilted when the contact 9 is lowered and contact I3 rides over and away from contact 9 through the tension of the spring |4 acting upon the contact l3. As soon as the contacts are broken the natural tension of the spring I tilts the rocking lever 9 in a reverse direction, the movement being limited by a stop- 9, and inaddition the spring |2 also tends "to force the rocking lever Sinto a horizontal position. As soon asthe wax becomes solid the switch can be closed again. To open the switch by hand it is only necessary to apply a momentary pressure upon the end of the plunger 9 in order to. depress the contactBe when the circuit is broken as herein set forth.

The switch is again closed before the wax becomes solid.

Fig. 1 shows a complete operative embodiment of the switch of Fig. 1, with the addition of a plunder 9 for closing the contact I3.

Referring to Fig. 2 a container l5.v is provided with a helical spring l6 partly embedded in wax. The upper coils are 01- a smaller diameter than the lower coils as herein set forth. The lower end of the spring I8 is connected to a terminal I! and the upper end is fixed to a ball or roller contact member I8, whose upward movement is limited by a flange |9 integral with the ball contact member l8.

A contact arm 20' rotatably mounted in the upper part of the container I5 is retained in position by means of a spring controlled plunger 2|, which may serve as: a terminal and said contact arm. 20 is moved by means of a switch arm 22 against. the tension of'a helical spring 23.

The switch is closed by hand when the wax is solid, by pulling the switch arm 22, when the lower end of the contact arm; 28. will slide over the ball or roller member |8 and the springgcontrolled plunger 2| allows 'for the upward movement of said contact arm 28.

When the wax softens through an overload passing through and heating the helical spring I6, this said spring is compressed due to the tension of the spring 23 'whichmoves the contact arm to the off p0siti0n,'and during this said movement, the ball or roller contact [8" moves downward and the spring controlled plunger 2| will remain stationary by reason of the tension of the spring It being less than that of the spring controlled plunger 2|. As soon as. the contact arm 28 has moved over the ballmember |8 to the off position, this. ball will again rise into its normal, position by the tension of the spring l6, and when the, wax is solid, the switch can be closed again. 7

Referring to Fig. 3 a, porcelain insulator 24 has, a helical spring 25 with coils of two difierent diameters inserted in a central aperture 26,. said spring 25, serving as a conductor is connected at the base of the insulator to a terminal through a plug '21. The upper end of the spring 25 is connected to, a lever 28 pivotally supported in a bracket 29 which in turn is fixed to the insulator 24'. The upward movement of said'lever 28 is limited by a stop 29.

A contact arm 38"pivotall-y connected to the lever 28, the lower end of said arm descending a 'short'distance beneath the lever 28, is provided with extensions 3| adapted to move along a slotted ramp 32, the lower endof the arm 38- is connected to the bracket 29 by means of a helical spring 33-, atan'gle to the lever 28 in order to counteract against the weight and leverage of arm 38- and weight and leverage of lever 28. The upper end of the arm is formed with a contact preferably consisting of a grooved wheel 34 which engages with a roller 35' fixed to a bracket 35' suspended by relief springs 31, from an overhead 'line 38, or another insulator. The electrical circuit is from, the overhead line '38 relief springs 3'|,bracket 36, roller 35, grooved wheel 34', arm 30, lever 28, and spring 25.

Theprovision of the relief springs 31 is to allow for the vertical movement of the bracket 36 so that the contact 34 on the end of the arm 30 can slide under the roller 35 when the wax is solid, in order to close the switch. Any suitable means may be provided for actuating the arm 38 when the wax is solid.

The switch after being' closed is automatically 3| to ride up the ramp 32 and swings the arm 3|! 3 clear of the roller 35; when the circuit is broken the tension of the spring 35 after breaking the circuit returns the lever 28 to its normal position, and as soon as the wax becomes solid the switch can be closed by moving the grooved pulley 34 into contact with the roller 35. Any suitable mechanical means may be applied for effecting the closing "ofthe switch when the wax is solid. The switch can be opened when the wax is solid by swinging the arm 38 away from the roller 35 when the springs 31- and part of the spring 25 above the wax substance is compressed to allow the pulley 34- to move away from the roller 35.

Referring to-Fig. 4 a container is supported by a helical spring '40 which is connected to a roller or ball contact member 4|) on the base of the container 39, the upper end of the spring 48- is connected to a conductor 4|: fixed to a part of the casing 42. The spring 40 is partly embedded in wax. A second ball or roller contact member 43 is connected through a helical relief spring 44 to a second contact member 45 fixed to a part of the casing. Slidably mounted in the casing 42 between guides 45 is a large ballor roller 41 adapted to move between the ball or roller contacts 4|) and 43. Said'large contact roller 41 is connected to a, plunger 48 for closing the circuit by'hand, against the tension of a spring 49 interposed'between a socket 58integral with a ball or roller 41 and a stop 5| fixed to the casing.

To close the switch by hand the plunger 48 is pressed inwardly until the large ball or roller has moved between the ball or roller contacts 40 and 43; during the inward movement of said plunger 48', when the wax is solid, the ball or roller 43 is depressed and. immediately rises after the ball or roller 48 has passed thereover. When an overload occurs, the wax will melt'thereby releasing thespring 40 which. allows the container'39 and ball or roller 48 to move upwards through the tension of the spring 49, being greater than the tension of the spring 40 forcing the large ball or roller 48 outwards and breaking the circuit. The circuit can be closed again as soon as the wax becomes solid.

Referring to Figs. 5 and 6 a stationary container 52 partly filled with wax or fusible metal is provided with a blade or leaf spring 53, set in the solid wax and secured to the base of the container 52 and at the upper end to a bush 54 rotatably mounted in the container 52.

A metallic projection 55 fixed to the bush 54 engages with a spring actuated plunger 56 when the circuit is closed. Said plunger 56 is mounted in a barrel 5'! which in turn is pivotally mounted on a spindle 58 extending from the side of the container 52. The barrel 5'! is rotated in one direction against tension of a spring 59 when closing the switch.

The switch is closed when the wax is solid by moving the spring actuated contact 56 across the projection 55 until it is interposed between said projection 55 and spring 59. Should there be any overheating which is conducted to the wax or metal alloy causing it to melt or soften, the tension of the spring 59 being greater than the tension of the spring 53 rotates the bush 54 and projection 55 and the barrel 5'] turns on the spindle 58 when the plunger 56 is swung out of contact from the projection 55, and the bush and projection finally return to their normal position.

Referring to Figs. 7 and 8 a container 60 is rotatably mounted through a spindle 6| supported in a. bearing 69. A blade spring 63 is partly embedded in wax and anchored to the base 64 of the container, and a terminal 65 is fixed to the upper end of the spring 63, and attached to the base board 65 A cam shaped catch 66 integral with the container 60 is adapted to engage with switch knife blades 61 as hereinafter set forth. The blades 61 are pivotally mounted (not shown) and fastened together by a metal block 68 provided with an insulated handle 69 for operating the switch. The blades 61 are spread apart by means of a helical spring 10 interposed between them as shown in Figs. 7 and 8, and a fixed thrust plate H is adapted to retain the blades in contact with the cam 66 when the switch is closed.

On closing the switch by the handle 69, when the wax is solid the blades are squeezed together on passing over the projection from the side of the container and the fixed thrust plate 10. To open the switch when the wax is solid in the container, the squeezing again takes place. Now the tendency of operating a spring (not shown) upon the blades in a similar manner to the spring 59 acting on the barrel 5! in Fig. 6 is to force the blades outwards, one of the knife blades is held by the projection from the container, therefore it has a force applied which tends to turn the container and at the same time to twist the spring 63. This happens when the wax softens, the blades are swung away from the cam 66 and the container returns to its previous position due to the natural disposition of the spring 63 before the wax becomes solid.

If desired the cam 66 may be fixed to one of the blades 61 instead of upon the container 60, also the blades 6! may move and the container is fixed or vice versa.

I claim:

1. A thermally actuated apparatus comprising a container provided with a wax substance, a

resilient member connected within the said container embedded in the wax and capable of movement in relation to said container when the wax substance is in a softened state, mechanical means associated with at least one of the moving parts being automatically actuated by the relative movement between said container and resilient member on the softening of the wax substance, said resilient member tending to restore the normal relative position of said container and resilient member while the wax is in a softened state, and means for operating the apparatus when the wax substance is in a solid state without altering the relative position of the container and the resilient member.

2. A thermally actuated apparatus comprising a container provided with a wax substance, 8. spring embedded in said wax fixed to the base of the container, a movable contact member connected to said spring outside the wax, a locking means engaging said movable contact member when the wax is solid, a contact member being automatically released from the locking means on the softening of the wax and means for operating said locking means when the wax is solid.

3. A thermally actuated apparatus comprising a container, a wax substance therein, a spring embedded in said wax fixed to the base of the container, a movable contact member connected to said spring, a spring associated with said movable contact member of greater tension than the first mentioned spring, a locking means co-operating with said movable contact member automatically released on the softening of the wax substance, and means for actuating the locking member when the wax is in a solid state.

4. A thermally actuated apparatus comprising a container, a wax substance therein, a spring embedded in said wax fixed to the base of the container, a fixed rod, a rocking lever slidably mounted upon said rod, means for limiting the movement of said rocking lever, a locking means co-operating with said rocking lever at one end automatically released therefrom on the softening of the wax substance, the opposite end of said rocking lever fixed to the spring and means for operating said locking means when the wax substance is in solid state.

5. A thermally actuated apparatus comprising a container, a wax substance therein, a spring embedded in said wax fixed to the base of the container, a fixed rod, a rocking lever slidably mounted on said rod, a stop limiting the movement of the rocking lever in one direction, a spring of greater tension than the first mentioned spring limiting the movement of said rocking lever in the opposite direction, a locking means co-operating with said rocking lever automatically released on the softening of the wax substance and means for operating said locking means when the wax substance is in a solid state.

6. A thermally actuated apparatus comprising a container, a wax substance therein, a helical spring with convolutions of two diameters embedded in the wax substance fixed to the base of the container, a fixed rod, a rocking lever slidably mounted upon said rod, means for limiting the movement of said rocking lever, one end of said rocking lever fixed to the spring, a locking means engaging with the other end of the rocking lever, a tripping means releasing said locking means when the wax is solid and said locking means automatically released on the softening of the wax substance.

7. A thermally actuated apparatus comprising a container, a wax substance therein, a helical spring with convolutions of two diameters embedded in the wax substance fixed to the base of the container, a fixed rod, a rocking lever slidably mounted thereon, connected to the helical spring, a locking means engaging with said rocking lever, a spring controlled plunger co-operating with said rocking lever releasing the locking means when the wax substance is solid and said locking means automatically released on the softening of the wax.

8. A thermally actuated apparatus comprising a container, a wax substance therein, a helical spring with convolutions of two diameters embedded in the wax substance fixed to the base of the container, a pivoted lever connected to said spring, an arm hingedly mounted in said lever, extensions integral with said arm, a slotted ramp,

a resiliently supported catch of greater resiliency than the tension of said helical spring co-operating with the free end of said arm and spring means for moving said extensions along the ramp and swinging the arm away from the catch on the softening of the Wax.

9. A thermally actuated apparatus comprising a rotatably supported container, a wax substance therein, a blade spring fixed at one end to said container embedded in the wax substance, a fixed 10 bracket connected to the opposite end of the spring, a cam integral with the container, a blade switch engaging said cam automatically released on the softening of the wax substance and spring means operatively associated with said blade 15 switch actuating the apparatus when the wax is solid.

ARTHUR GEORGE BULLEN.

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