US2912535A - Temperature and earthquake responsive electric switch - Google Patents

Description

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TJ. svuLLwAN I y, Namo, '1959 wammzm ma @om menue. swnca 2,912,535 TURENDEARTHQUAKEMSPNSIVE TEMP ,-ernennt:swrrcuv l Timothy I.k Butte, Mont., assignor to `Sullivan Valve and Engineering Company, Butte, Mont., a cor-` :pox'ation of Montana .l c

Application October 3, .1957, Ser-Zal No. 687,944A f3 (Cl. 200e-61.48)

` *This invention relates generally to an electric switch,

' and more particularly yto an electric switch which is responsive-,both to excessive temperatures yand to shocks caused by vearthquakes and the like. v

In many industrial installations 'it is desirable to iny,

clude switch means in the eleca'ical power supply'of associated electrical equipment which will interrupt the yelectrical service upon the presence of excessive temperature caused by re or overheating of equipment or upon l excessive shocks, vvibration or impacts caused by. earth- J qualcos, explosions and the like. prior art to use separate switch units for controlling an lt-is vwell known in the.

electrical circuit, one unit being responsive to earthquake shocks and the other unit being responsive to temperaturc. Y The present invention was developed to provide a single switch unit which is responsive to both excessive temperature and to shocks and vibration. v

.Y Thus the primary object of my invention .is to provide an electric switch which is responsive to both excessive L f l temperature and to shocks caused by earthquakes and the j like. v

' A more specific object of my invention is to provide an electric switch having a movable contact clement held into engagement with a stationary contact by 'means of a pivotally-mounted shock-responsive member in combination with a temperature-responsive member arranged to actuate said shock-responsive member to cause disengagement of the movable element from thestationary contact.A u

Other objects and advantages of my inventicn'will become more apparent from a study of the following specil iication when considered in conjunction with the accomg `partying drawings, in which:

Fig. 1 is a plan-view of my` temperature and. earth- Quake responsive switch; l

` Fig. 2 is an elevational view of the switch in its preset, closed position; A

Fig. 3 is lan elevational view of the switch in its open position; and

I housing2 tends to urge the movable Contact element 11 y i upwardly into contact with the stationary contact 7".

Rigidly bolted to one wall ofthe housing 2` is a bracket-v f 13 having a lateral portion which extends above the movable contact element 1l. Bracket 13 hasa socket seat 13a therein upon which is rotatably supportedb'all 14 rigidly connected to retaining* shaft 15 intermediate its element 1f. when the shaft isV in its vertical position to hold the movable contact element 11 in engagement with I, stationary contact 8" against the upward biasing force of ccmpressedspring 12 as shown in Fig. 2. Slidably mounted in aperture 2c in one wall of the housing 2 is the actuating rod' 17 having an enlarged head Aportion 17a at one end thereof within the switchhousing kand a hooked portion 17b at the other end externally of the switch housing. Compressed spring 18 positioned about the rod 17 intermediate the enlarged head portion 17a and the wall of the housing 2 tends to bias the rod 17' toward the shaft 15 to knock the lower extremity of shaft 15 from the vertical projection 111i as will be explained in grcate'rdetail below. v Rigidly bolted to the housing 2 is a lateral bracket 19 having ahooked portion 20 at its outer extremity. Re-

movably connected at one end to hooked portion 17b of rod 17 and at the other end to hooked portion 7.6 of bracket 19 is a tem erature-responsive fusible link element. 2l. The fusible link element serves to maintain the rod 17 in its retracted position against the tension of spring 18 as shown in Fig. 2.

' The switch housing 2 is mounted 'to the fixed support 23 (which maybe a structural portion of a building, heating unit, gas boiler or the like) by means of brackets 22. A cover 2b is removably secured to the housing .2 and constitutes the top land from wall of the housing. Y Removal of the cover provides access tothe housing for resetting the'switch as will be explained in greater detail below. t

In making the electrical connections of the switch, input leads 5 and 6 are connected in series with the power line of the equipment to be controlled and input lead 4 is connected to a suitable alarm circuit which provides visible or audibleindication of the opening of the switch power contacts.

The operation of the earthquake and temperature responsive switch may now be set forth in detail. v

When the switch housing 2 is secured to the support 23 by brackets 22 and the cable conductors 4, 5 and 6 are connected to terminals 7, 8 and 9 respectively, the

Fig. 4 is an end elevational view of the housing and its cover.

Referring now more particularly to the drawings, a

the cable C are connected to the switch conhzct terminals 7, 8 and 9 respectively. Terminals 7 and S are connected by means of internal leads 7' andv 8' to the stationary' switch contacts 7" and 8",'and terminal 9 is connected will be made with contact 8".and when the-contact is in its upper position asshown 'in Fig. 3, electrical contact willbe made with contact 75'.

Compressed coil spring 12 positioned intermediate the f y movable contact element 11 and the bottom 2a of theY switch unit 1 is `rigidly secured withinthe metal housing l 2 by means of bolts 3. Lead-in wires 4, 5 and 6 fromA weight member 16 is lifted in its uppermost position as vshown in Fig. 2 and retaining shaft 1S is pivoted about bail 14 and socket 13a toits vertical position. The lower extremity 15a ofl shaft 15 engages projection 11a and\ holds movable contact 11 into engagement with stationary contact 8" against the upward `biasing force of compressed coil spring 12. Thus a completed circuit is estab` l lished between conductors 5 and 6 through internal lead c 9', movable contactk 11,v stationary Contact 8, and internal lead S'.

Since conductors 5 and 6 are connected in series with the Aelectrical power supply to the associated electricaly equipment, normal functioning of the c equipment will be established upon throwing the main power switch. Fusible element 2l. connected between the bool; 20 of stationary bracketV 19 and the pro'ection 17b of actuating rod 17 serves to maintain the rod in its retractedposition shown in Fig. 2 against the biasing action of compressed coil spring 18.

'Upon theoccurrence of shock to the support 23, as

yliaterxted Nov. 10, 1.959 i yvibration-ur ne use, *ne

member 16 will be moved vfrom its vertical position above the pivotal axis of ball 14 in socket seat 13a, and lateral downward movement of weight member 16 will cause retaining shaft 15 toV pivot from its vertical orientation about the ball andsocket connection to an oblique orientation as shown in Fig.3. The lower extremity 15a of shaft 15 will 'ce disengaged from theprojection 11u, and

Vmovable contact 1l will be pivoted upwardly about pivot f lllfrorn Ystatirmary contact 8" and into `engagement with-10 stationary contact 7" by the vertical explosion loiveoil spring 12.' vThus the electrical connectionbetween power .conductors and 6 will be broken, and the alarm rcircuit containing conductor 4 will be closed through internal lead 9', movable contact element 11,.s tationary contact f 7", and internal lead 7'. v

' Upon the occurrence ofv excessive temperature caused by lires, overheating of equipment and the like, when the switch is in the closed position of Fig. 2, the temperatureresponsive fusible link 21 will be broken and spring 18 will expand to causeactuating rod 17 to move toward the vertical retaining shaft 15. The enlarged bead portion 17a ofthe rod'17 cornes into engagement with the shaft andthe force of spring 1S knocks the lower extremity of the shaft 15a from the projection 11a so that movable e contact element 11 is free to be pivotally moved upwardly out of engagement with stationary contact 8 and' into engagement with the alarm circuit stationary contact 7"" center lof gravity of weightA v j shock and which has a durable, trouble-free arrangement.

A rigid parts.

constructed from a minimum of relatively inexpensive,

While in accordance wi the provisions of the patent statutes Ihave illustrated and described the best form of embodiment ofmy invention known to me, it will be.

. apparent to those lskilled inthe art that other modificaby expansion Yof coil spring 12. It is important to point" nut that the jar or shock imparted to the portion of shaft 15 below the universal pivotal mounting of ball 14 in socket 13a .is imparted to the weight member 16 through the shaft so that they momentum of the weight' member 16 about the ball and socket pivot axis will assist in causi ing pivotal movement of the retaining shaft out of engagement with projection 11a to releasemovable contact v member 11.v

The structural arrangement of the switch is such that the actuation can bemade to be quite sensitive, since the weight of themember 16 is great with respect to the weight of the shaft 1S and ball 14, and the seating of the ball 14 upon the socket 13a may be made to be very delicate since the upward force upon the lower extremity 15a of the shaftby the projection 11a serves to vsteady the shaft 15 in its vertical orientation.

In order to reset the switch after it has been opened due to shock or vibration, the cover 2b is-removed and the vtions can be madel in the apparatus disclosed without devtating from my invention as defined in the following claims.

` I claim:

l. An electricswitch comprising afhoush'xg, a stationary contact in said housing, a movable contact pivotally mounted in said housing above said stationary contact,r

electrical conductors connected to ,said contacts, spring means biasing stud movable contact away from said stationary contact, impact-responsive means normally :naintaining said movable contact into engagement with said i stationary contact in opposition to the biasing force of said spring means and adapted to release said movablel contact from said stationary contact upon the importation of impactr to :said housing, said impact-responsive v.means comprising a fixed member secured to said houslng above said movable contact, said. member having a circular opening extending therethrough'the peripheral'` edge of which forms a universal ball socket, a. ball member rotatably supported upon said ball socket, a retaining shaftrsecured intermediate its ends to said ball member, j

a Weight member secured to the upper end of said retaining shaft,y the lower portion of said shaft extending through said opening in engagement with said movable contact when the shaft is in a vertically-balanced position to maintain said movable contact .in electrical engagelment with said stationary contact, and temperatureresponsive means for actuating said impact-responsive means to release said movable contact from said stationary contact'upon increase of ambient temperature above a predetermined value-comprising an actuating rod slidably mounted in said housing adjacent said impactresponsive means, spring means urging said rod axially .in adirection to cause engagement thereof with the lower portion of said retaining shaft to impart an impact to said shaft, and a temperature-responsive fusible link eleweight member 16 is pivotally raised to the vertical position so that the lower shaft extremity 15a will contact projection 11a` to urge the movable contact 11 into engagemcnt with stationary contact 8".

To reset the switch after it has been opened after Y breakage of the fusible link 21 upon the presence of excessive temperature, the broken parts of the link are rcmoved and a new link is connected at one end to projection 1721 of rod 1'?. The rod 17 is then pulled to the right in Fig. 3 to compress the spring 1S and the other end of the link is hooked upon the stationary hook 20. Cover 2b is then removed and the Weight member 16 is 'pivoted upwardly vuntil the lower shaft extremity 15a again engages projection 11a to urge movable contact 11 into engagement `with stationary contact 8,".

Eos it is apparent that my invention provides a switch which is extremely sensitive to both temperature and ment connected at one end to said housing and at the `other end tosaid rod to maintain said rod in asenfacted position out of engagementwith said retaining shaft. j

2; An electric switch as defined in claim l wherein said actuating rod extends through one. wall of said housand said fusible link element is mounted externally of said housing.

3. An electric switch s desired in claim 1 and further including a second lstationary contact in said housing on the other side of said movable contact from said stationary contact, said movable contact spring biasing means tending to urge said movable contact in a direction to cause engagement thereof with said second stationary contact. x

References Cited in the tile of this patent` UNrrnD srATEs PATENTS 1,803,623 I Lang et ai; May 5, 1931 2,768,256 Barten oef. 23, 195s 2,778,896 Tollefsen Ian. 22,1957'k

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