US1772442A - Automatic electric switch - Google Patents

Description

' Aug. 5, 1930. c. E. HANNY I AUTOIATIC ELECTRIC SWITCH Filed July 21, 1928 NVENTOR have been far from person knowing little of such .both'life and pro 5 lessly add Patented A1155, 1930 A UNITED STATES PATENT OFFICE cmnms 12.3mm, or UNIONVILLE, CONNECTICUT, assrenon 'ro 'rma 'rnmm -ELEC'1BIG MANUFACTURING COMPANY, or (PLAINVILLE, CONNECTICUT, A coarom- TION OF CONNECTICUT Application filed July 21,

Switches of this type have usuall consisted' of a metal box havin a hinge cover and enclosingfa switch and ses and having an external oper ting handle.

The covers oft ese boxes have usually been merely latched in closed position so as to permit the ready opening ofthe same by the genant in order to insert or replace blown uses. I

The results of this typeof construction satisfactory because, for

instance, the entire switch construction be- -i ng free of access, the tenant is strongly tempted to over-fuse the installation or to add new circuit lines and thus overload the circuit to such an extent that the fuse receptacles or clips cannot receivefuses of large I I enough capacity to properly protect the circuit. In the event of the ses blowingrepeatedly, the tenant is strongly tem ted to bri ge the.

(and sometimes actually does fuse terminals with coins or ot er. metal objects, thus endangering not only'the various electric devices in the circuitbut also causing a tremendous fire-risk by the over-heating at imperfect joints, short of wires, arcing circuits, etc.

Further, the tenant, in most instances, must furnish his own fuses and, the average I matters, may purchase fuses ofsuchsmall capacit that they will'blow repeatedly or he maymstaIl fuses of greater capacity than the installation is intendedto-carry and thus endanger erty. "In-these days, 0 the rapidly increasing introduction of new electrichousehold-and office devices, it is the rule rather than the exception, or the general public to thoughta more and more newdevices and attach them in one way or another to circuits which may already be loaded to maximum capacity. Thusit' is highly desirable that general public use in residences,

au'romrrc nnnc'rmc swrrcn 1922. semi m. 294,518.

locked box and having an external handlefor normal manual operation, the automatic (por- 4 tion of the construction bein calibrate central service station attac s and being normally inactive but 'functionin to entirely open the circuit on overload of s ort circuit conditions.

My invention aims to provide the combination of a manually operated switch for normal operation and a normally inactive automatically operated auxiliary switch for protection against overload or short circuits.

One object of my invention is to provide an enclosed switch construction having. an external operating handle, a manually operable switch for normal operation and a normally inactive auxiliary switch ada ted to automatically open the circuit on either a gradual overload, a sudden excessive surge in the circuit or a short circuit.

Another object is to provide an automatic safety switch of fuses or other replaceable parts and which may be calibrated by the central station employees and then locked or sealed so as to which will not reqmre the use prevent access to any of the switch parts or 7 terminals by the current consumer.

Another object is to provide a construction of thischaracter which will have sufiicient time lag to prevent the automatic operation of the switch by the usual surge in the circuit caused by the initial closingmovement of the switch.

Another object is to provide, in a construction' of this character, a combined heater unit and electromagnet so associated with a bimetallic thermostatic latch "as to cause the automatic' operation of the latch'but. without any current flowing through the latch.

. Another object is to provide a combined heater and electro-magnetic coil of the? receding descri gsion directly in the circultto be controlled ut of such carrying capacity .as-to ofier practically no resistance to a nor- Neither ofthe switch members need be of any exact typebut I have chosen to inco rate my invention a construction. sim: at to that shown in the Getchell Patents Nos.

1,677,331 and 1,677

loo

Detailed descriptions and difierences e be further disclosed as the specification pro.-

' ceeds.

In carrying out the invention in the prean auxiliary contact. This quick-break ferred manner, I provide aninsulating housing which carries the various conducting element's. [The latter includes a manually operable main switch for normal'operation and Ya quick break switch for automatic'operation, the automatic switch preferably having switch is held in closed circuit position by means of a latchwhich is not included in the electric circuit but which is adapted to be thermostatically operated by reason of a gradually increasing overload and which is adapted also to be instantaneously operated; electro-magnetically by a sudden excessive overload.

The unit which includes the housing, the

switch and the latch mechanism is adapted 'to one form of apparatus embodying my inven tion, showing the manual and automatic switches in the open circuit positions in full lines and, in dot and dash lines, showing the inanually operable switch member, and the automatic switch members in position for resetting the automatic switch. Fig. 2 is an exploded perspective view of parts of the switc static latching member engaged with a part of the automaticfi'switch member to latch the latter member in closed circuit position. The stationary 5 is secured to the insulating body or ousing 6 by means of a screw 7, and supports the main switch blade 8 on the pivot pin 9. The stationary contact or 'aw 10 of the switch is secured to the body 6 y screw 11 which erably adapted to be manually operated by means of a crank arm 01f rod'.13junder all normal'conditions.

The circuit terminal 14 is secured to the opposite end oftli insulating body 6 by a screw The stationary contact plate 16 is secured to the body 6 by means of a-screw 17. The

bracket 1 8 is secured to the insulating body by means of screws 15 and 17 1 The movable contact member 19 is pivot ally supported ,by an arm of the frame 20' which is in turn carried'byfthe pivot pin 9.

' .The arm 21 is also pivoted on pin 9 and is embodying my invention. Fig. 3 is a detail view showing the thermo-' aflso secures in place the line terminal 12. The switch blade 8is prefprovided with a contact roller 22 adapted to coact' with the contact plate 16.

The cross bar 24 which is secured tothe arms 21 is electrically connected by strip 25 to the stationary switch base 5. The contact member'19is similarly connected by a flexi ble strip26. a

A spring 27 is interposed between the insulating body 6 and the rear end of the contact member 19 so as to apply pressure tending to move the two movable switch contact members 19 and 22 awayfrom the stationary contact plate 16. v I I :A pin 28 connected to the contact member 19 extends thru the cross bar 24 and is surrounded by a-spring 29 which tends to draw the contact member 19 toward the arm 21-.

The bimetallic thermostatic latching member 30 is rivetted or otherwise suitably secured to bracket 18 and has its movable endadapted to engage the latch'carried by the tilting frame 20. This latch has an abutment 31 and a movable abutment 32. A screw 33 serves as a convenient means for adjusting or calibrating the abutment 32 which projects more or less beyond the abutment 31, thus making 1t possible to adjust the sensitivity or point of release ofthe thermostatic member ,To reset the switch or close the circuit from the position shown in Fig. 1 the manually operable switch blade 8 is moved toward the dot and dash position. The pressure of the switch blade 8 against the cross pin 35 of the tilting frame 20 moves the frame to the dotand dash position'of Fig. 1. 'Ilhiscompresses the sprin 27 and forces the lefthand end of the mova 'le switch member 19 into engage: ment with the stationary contact plate 16.

This movement also carries with it the pin 28 and compresses the spring 29 so as to move the contact arm 21 and bring the contact roller 22 into engagement with the stationary contact plate 16, thus placlngboth of the springs 27 and 29 in compression.

This movement brings the tip of the latch 32i3nt0 engagement with the tip of the thermostatic member 30 as shown in Fig. 3 and thus'latches the members of the automatic switch in the closed circuit position.

When the auxiliaryswitch is latched in closed circuit-position the manually oper- -able knife blade switch 8 may be closed and the entire circiiit completed thru. the elements12, 10,8, 5, 25 and 26, 22 and 19, 16, 17, 18,42, 40, 41, 15 and 14. Obviouslythe -.circuit can be opened manually when desired by moving the switch blade 8.

In serieswith the circuit thru the switch is the coil 40, the terminal plates of which,

41 and 42, are separated by an insulating washer43. This coil is preferably covered with asbestos insulating material so as to insulate the, individual coils and to retain the eat.

The two elements and 45 constitute re spectively the armature and the core of the preferably bar free to warp or bend when heated.

. The core member 45 may be secured to the insulating cover 46.. The latter is preferably "provided with a hood-like '10 portion 47 having a recess or pocket 47 which surrounds the coil 40 but preferably leaving some open spacefor the radiation of the heat from the and coil. Preferably this cover 46 and the hood- 47 are formed of insulating materialof an asbestos character and the pocket isso posi tioned as to concentrate the heat of the coil adjacent the bendable portion of the bimetal lic thermostat member 30.

The cover 46 may. place for instance b extending -thru anc carried thereby. I

.Incase the circuit is slowly overloaded the coil 40 will heat up the adjacent thermostatic bar 30 and release its tip from the latch 32 thus allow the switchto open automatically. In case the circuit is suddenly andexcessively overloaded the magnet coil 40 will instantaneously draw the armature-'44 toward the core and bend the bar 30 so as I. the circuit.

set or calibrated, the

' common enclosed to release the switch and automatically open By adjusting the screw 33 the switch may be calibrated to open automatically under any desired overloadcondition;

After the auxiliary switch has once been sealed and then, sofar asthe-current consumeris concerned, the device-is positively limited to carry only a certain predetermined load and will automaticall openthe circuit as soon and as often as t e predetermined capacity is'exceeded and regardless of any attempt to prevent or delay the automatic operation. g

.It will be noted that, in this construction,- the noil'lmal operation requires nothing more than t e manual operation of the switch 'ablad in -exactly the same, manner as a thejlil tomatic auxiliary switch is adapted to remain closed at alLtimes except when automatically released latch or y either the thermostatic the.electro magneticcoil.

b When-tile auxiliary switch has been opened "lautomaticall ,itJinai be re-set or are-latched by the simp e switc opening movement of the blade 8,.but the -complete circuit cannot be re stablished untilthe auxiliary switch has first beenre-latched in this manner, after which the main blade 8 may be closed tocompletefth'e circuit. This last feature is of greatimportance because the auxiliary switch contacts are 'ofthebutt type and,

assemble the parts, H duced and, by reasonof there being fewer be suitably secured in a number of screws 48' orage members 49 into the body 6 or some element such as a nutstatic latch for said box may be locked or main switch member,

tion-abetivveen the switch for the reason that switch an tages of this are that there can be no arcing at the'latching point as the latch is released-- there is no danger of injuring the latcn'by a short-circuit or excessive overload-the number of electrical joints is reducedfewer operations are therefore the cost( is reparts, the device is moredependable because there is less likelihood of the parts movin thus disturbing the cahc or loosening and bration to which the device has been set.

I claim: v 1. A switch including an insulatin housing, a movable switchv member, a t ermoswitchmembe'r', a stationary coil'enclosedin said housing adjacent said latch for heating and bending said latch I and for magnetical attracting said latch to release saidmovable switch member.

2. A switch including 'an insulating body, a movable switch member supported thereby,

athermostatic latch member for said switch member and having a magnetic armature secured thereto, a heat'retaining cover for said body, and acoil enclosed by said'body and cover for heating said latch member and being concealed from the operators vision,

required to produce and also for magnetically attracting said armature "on predetermined overload conditions in the cover in and a core member -secured proximity to said armature.

3. A switch including a manually operable an auxilia member, in-series therewith, a 'catc for the auxiliary switch member,a bendable thermostatic latch for holding said catch andsaid switch auxiliary switch member means of connecberwhereby said catch maybe reset by the action of the manually member, and a coil for electro-maghetically and for-thermally-bending said latch to release saidauxiliary switch. a r

The combination in a quick break switch of a spring-pressed switch member, a bendable thermostatic latch for holding said .switch' member in closed position and an in series with said operable main switch latch beingroperable both ther manual] operable main y I switch member and the auxi 'ary switch membeing entirely free of circmt v 5. The combination with a quick-break and closing switch of a thermally bendable element for latching said switch in closed position and a magneticallyoperable release device having a coilin' electrical circuit with, said switch for heating said element and having an armature directly associated with said element and cooperating with said coil to release said switch on excessive overload in the circuit,

the said bendable latch being normally free of direct contact with said coil.

6. The combination'in a quick-break switch of a bendable bimetallic latch normally holding the switch in a closed circuit position, an electro-magnet ..coil in series with the I switch for automatically heating and benda circuit, a bimetallic latch mem her in said recess for holding the switch,

mechanism in its closed circuit condition, an

armature member secured to the latchmemher, and a stationary coil serving to warp the latch when heated and serving to magnetically attract said armaturewhen quickly overloaded.

. CHAR ES. E. 111m.

-' ing said latch to releasethe switch on an ordin overload, and an armature carried by said a'tch and adapted to be attracted by said magnet in the event of an excessive overloadin the circuit the-said bimetallic latch and said armature said soil. I 7. The combination in a switch of a movable switch member, a spring for moving I said switch-member to open position, a bend= said auxiliary switch in closed position, a magnetic (soil for thermally bending said latch to release said auxiliary switch and for electro-magnet-ically bending said latch to release said auxiliar switch, the said bendable latch being in ependent of the circuit and free of allcircuit winding.

9. In a switch construction the combination of a pivoted frame, .a spring-pressed being normally free from 7 contactmemberv hinged to said frame, asec. .ondary pivoted contact member, a resilient? connection between said contact members providinglimited relative movement between the same, a'latch member coacting withsaid frame to hold said frame and its contact members in closed circuit position, a -cornbined electro-magnet and heating "coil for "longed overload, and for. disengaging said latch memberon a sudden predetermined ex-.

' cessive overload. 1

10. A switch construction comprising an insulating bod having a recess, snap action switch mechamsm having manually operable -'means on one side of the body. for opening "disengaging said latch member on a prov

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