Патент USA US2132922код для вставки
Oc'f. 11, 1938. P. S. BEAR ' 2,132,922 _.swITcH Filed April ll, 1936 2 Sheets-Sheet 1 _ /Z 21 27 28 „1,114 willi”, 17:15!" Oct. l1, 1938. 2,132,922v P. s'. BEAR SWITCH Filed April 11, 1936 2 Sheets-Sheet 2 \\\\ \\\\ Q3 1. .?3. . . XÀÑÃO fai-:lss-ur-:n Patented Oct.’1`1„1938 JUN 3- 1941 " 2,132,922 'i UNITED STATES PATENT-_ ol?rlcr.A 2,132,922 SWITCH Paul S. Bear, Elkhart, Ind., assignor, by mesnc assignments, to Bucklen-Bear Laboratories, Inc., Elkhart, Ind., a corporation of Indiana Application April 11, 1936, Serial No. 73,883 24 claims.' (cl. zon-152) tact, as distinguished from the 'substantially This invention‘relates to switches, and more particularly is directed to switches of the metal point contact that occurs when two curved sur faces are brought into contact. envelope type employing mercury as the con ', tactor between spaced metallic electrodes. Also, heretofore, when the switch' was slowly In my prior copendlng application, Serial No. tilted toward circuit closing position, consider- 5 745,842, September 28, 1934, I have disclosed a f able frying and sputtering of the contact surfaces switch construction employing a cup-shaped occurred as they moved into engagement. With metal shell of stainless steel or the like, having the present construction, a slow motion closing an enlarged open end receiving a refractory or of the circuit is possible without these attendant lil ceramic member sealed in the end of the shell disadvantages, and the capacity of the switch is >10 and supporting a second electrode in spaced re considerably increased without any danger of lation to the shell. The present invention con such frying or sputter-lng. Even on lamp loads, stitutes a modification in the design and assem where the closing arc is excessive, tending to bly of such type of mercury switches for imparting produce overheating of the interior of the switch, 1.; to such swìtches’improved operating character the present design of switch takes care of such -15 istics. loads easily without any material heating, and ` _c . I have .found that a mercury switch can- be ‘ operates under such loads at temperatures only provided having greatly improved operating slightly above the adjacent room temperature. The mounting of the ceramic insert Ain the switch envelope as disclosed in the present con- 20 struction is such that no portion of the ceramic characteristics by treatment of the mercury it self, as described in the copending application of lmyself and Herbert E. Bucklen, Serial No. 67,816, filed March 9, 1936. With this im proved mercury contacting body, and the em ployment of a¿ liquid alkaline 1111,' such as trl is placed under tension, the sealing gasket and the support of the ceramic in the metal envelope being such that the ceramic is subject only to compression stresses. This materially lessens 25 any danger of cracking of the ceramic during ethanolamine, a switch can be produced which is capable of carrying relatively high current, and which can give consistent repeat perform ance by reason of the retention of a‘stable body operation of the switch when internal pressures may be developed due to heating or the like. Another feature of the present invention is the of mercury in contact with the second electrode. ` 30 Reference is made 'to my copending application- positioning of the ceramic in thermal contact 30 ,Serial No. 53,146, ñled'December 6, 1935, for a with the metal envelope, whereby any heating of full disclosure of these features. the ceramic will be dissipated by -radiation from The present invention, in its preferred form, is the-external surface of the envelope. This ma directed to the provision of a metal envelope type terially increases the capacity of the switch to high currents, since the heat generated upon 35 - of switch having an internal construction such that a greatly increased area of contact between the two contacting bodies of mercury, or between a moving body of mercury and a stationary elec making and breaking of contact ,in a high ca pacity switch is thus readily dissipated externally c of the switch.. In this connection, I employ a trede, is produced, whereby the capacity of the refractory material that is thermally conductive, so that no localized heating of any portion of the 40 40 switch is increased to an. extent not hitherto possible in switches of this type. This is accom plished by providing a polygonal-shaped en velope with a ceramic,insert having a planar runway across which the moving body of -mer ceramic is possible. The use of a limited alka- - line' liquid ñll is also instrumental in affording dissipation of heat to all portions of the switch envelope. ‘ . ' The ceramic employed in the present switch 45 ' cu-ry moves into and out of contact with a re tained stable body of mercury which is in contact is designed in such >manner as to provide a. rel with the electrode. The stable body of mercury atively long leakage path between the central `lies in a straight line along a sharp cutting edge ' electrode supported in the ceramic and the sur rounding wall of the metal envelope, thereby and presentsy an area. of contact which is con 50 siderably increasedover that provided with the eliminating any tendency of shorting the circuit` 50 usual ' cylindrical type of metal switch. «In between the electrode and the envelope across effect, I obtain a straight line advancing edge the ceramic externally of the switch chamber. cf mercury and vretain a straight line contacting By the use of the present construction, produc ing the elongated leakage path, I also provide surface of mercury whereby a greater cross 55 section of mercury comes into simultaneous 99D- Ä for the resilient gasket which seals the ceramic u . . .1, 2,122,922Figure 4 shows the mounting of a switch em 2 in position in the envelope to engage the ceram ic in such manner as -to subject the same to com-l pression, so that' any internal pressures devel oped in the throat of the ceramic serve onli7 in overcoming this compression stress, and do not place'any tension _upon any portion of the ceramic. bodying the principles of the present invention >stresses being placed upon the ñber members construction. within a moi-ded case; - ' Figureâ is ,a sectional view taken substan tiallïvì on line 5-5 of Figure 4; ' . Figure 6 is an elevational View of the contact The present construction is also advantageous ~ lug retaining washer shown in Figure 4; Figure 'l is a modified form of electrode con in that the diameters of the electrode support ed in the ceramic and of the retaining ring struction; and _ 'Figure 8 shows a switch of the present inven 10 l10 which is employed to compress the gasket during the assembly of the’switch prevent any shear tion embodied in a water jacket heat dissipating enclosing the outer face of the ceramic. This prevents, to a large extent, any danger of the 15 internal pressure being such as to force the elec trode axially outwardly of the switch envelope, since the intermediate gasket means between the outer face of the electrode and the compression ring will be subjected to stresses other than straight shearing stress, and consequently have . Referring now in detail to the switch shown in Figure l, I provide a cup-shaped metallic en velope Il) having the enlarged cylindrical por 15 tion I2 jointed to the main portion of the en velope by the frusto-conical section I3. A suit able ceramic insert I4, preferably formed of porcelain, and having an cuter deñning surface conforming to .the internal surface of the por 20 a much greater resistance to such movement of ` tion I3 of the enveiope, is inserted into position, the electrode. K . My invention also contemplates the provision of a switch assembly havingA a novel type of con tact lug- retaining washer, the entire assembly its position being determined with respect to the portion I0 of the envelope by means of the align ` ing groove I5 -formed in the ceramic insert and engaging over the struck up boss .I6 in the en being capable of being enclosed within a mol-ded velope. in the case, or at points 'disposedein any angular ing body of mercury I1, vwhich mercury may be 30 ' . The portion I0 of the -enveloperis preferably case formed of a phenol condensation product or the like, and capable oi' adjustment so that " `square in section, although it may be of any the leads may be brought out at the same point desiredpolygonal shape, and contains the mov _ relation, as desired. cleaned and treated in the manner disclosed in ' » A Astill further advantagesecured by the pres ent invention is the provision of a construction Vius such that maximum contact area is provided be tween the retained body of merc and the sur face of‘the electrode, whereby he resistance to current passage between thelmercury and the electrode is reduced, so that a suñ‘icient area of contact is provided to prevent any overheating 40 at this portion A,of the switch. , my above mentioned copending application. The ceramic» I4 is provided with an inclined frusto-pyramidical opening I8, -terminating at the smaller end in a sharp cutting edge i9 de 35 vfined by the walls 20 which extend normal to -the axis of the ceramic. A suitable electrode 22, which is in the shape of a circular disc member and which is provided with the extend ing stud portion 23, isspaced outwardly of'the 40 ‘ . I also contemplate, in the present switch con struction, the enclosing of the switch within a walls 20 and closes the outer end of the opening water jacket or the like, whereby the switch 'I'he ceramic I4 is provided with an axially extending annular ñange 24 within which the electrode 22 is seated, and a suitable cup-shaped 45 resilient gasket 25, which may be formed of syn thetic rubber or the like, is disposed about the extending portion 23 of the electrode and has the annular flange portion 26 disposed about the flange 24 of the ceramic `and in engagement with 50 the internal surface of the portion I2 of the en may operate under heavy loads and any heating 45 which' may occur will be readily carried away by the circulating water in direct contact with the external surface of the metallic envelope. I also provide a Vmetal envelope having two diameters, whereby the enlarged portion of the envelope is adapted to receive the ceramic in „50 sert and the sealing means, while> the smaller portion oi’ the envelope is used to carry the mov ing body of mercury, andi'orms the other elec trode. By the use of this construction, I provide 55 for adequate sealing and closing meansî with suflicient electrical clearance between the stud and the shell, and yet produce economy in the amount of mercury'which must he employed in the switch, as well as keeping the size and weight of the switch at a minimum. I8. . velope. The gasket is compressed against the internal surface of the portion I2 of the envelope and against the external- surface of the ñange 24 by means of the fiber washer 21 which is car 55 ried about the stud 23 and which engages the rear face of the gasketJ 25. v'Ifne' washer 21 is urged inwardly by means of the compression ring 28, formed of any suitable material, which is L moved inwardly by beading over the end 29 of 60 ' Other objects and advantages of the present ' the portion I2 of the envelope. This beading or spinning‘over of the end 29 compresses the gas -invention will appear more fully from the fol ket` 25 in position to seal the space between the lowing detailed description, which, 'taken in con junction with the accompanying drawings, will 65 disclose to those skilled in the art the preferred construction _and operation of the present in ventiom- n - between the internal surface of the ñange 24 and - In the drawings: , Figure 1 is a vertical sectional view through 70 ' aswitch embodying the principles of the present invention; « c Figure '2 is a vertical sectional vi'ew through a modified forml of switch;` Figure 3 is a sectional‘view taken substantially o. on line 3-3 of Figure 2; external surface of the ceramic and the internal ` surface of the portion I2 of the envelope, and 05 to also seal any clearances which may be provided ’ . , the stud 22. It will be noted that the leakage path between the portion I2 of the envelope and the electrode 70 22 is increased by this construction, and thus the danger of shorting the switch by' a short circuit flash-over betweenV the stud 22 and the portion I2 of the envelope is substantially eliminated. The stud portion 23 of the electrode 22 is pro- 75 3 2,182,222 vided with a suitable nut 30 threaded thereon, which engages a washer 32 that serves to com press the washer 21 against the gasket 25. If desired, arsuitable insulating spacing bushing " 3l may be provided to position the washer and nut out of a possible- ilash-over >position with ‘respect’ to the vcompression ring and edge of the envelope. ~ I preferablyy form the ceramic Il of porcelain, 10 inV that porcelain is a thermal conductor having I3 in the recess formed between the wall 2l and the face of the velectrode 22 to be also maintained in a straightfline. Thus, the meeting edges of the two bodiesfof mercury produce a straight line contact across the entire width of the opening. 5 This materially increases the cross-sectional area of mercury which comes into contact, -thereby allowing a much heavier current to be passed through the contacting surfaces. The capacity of the switchis thereby materially increased. The rectangular pocket formed between thel a conductivityv rating which, while not as good as iron, is~ in close proximity thereto. Further electrode 22 and the walls 20 in the construction more, porcelain is free from metallic oxides that vshown in. Figure l retains a body 4of mercury give ofi’ free oxygen in areasV subjected Vto anr which is of a width such as to have inherent electric arc, and therefore the use of a porcelain stability. The advantages of the retention on~ ceramic insures that no impurities will'bevin such a stable body of mercury whose meniscus troduced into the interior of the switch envelope l‘rises above the sharp cutting edge over which which might prove deleterious to switch opera contact is> made and broken have lbeen pointed tion. Certain ceramics, such as those known out in detail in my copending application, Serial ' 20 commercially as “Alsimag" andv “Isolantite”, No. 53,146, filed December 6, 1935. while perfectly adapted for use as far as mechan I have ~found that by changing from a cylin ical fitting _of parts is concerned, are not desir drical form of switch to the polygonal envelope able in alswitch of this construction, since they type of switch, an increase. in effective contact are relativelyv poor thermal-conductors, that is, area, when lthe envelope type is of a diagonal di excellent thermal insulators. This means >that . mension substantially equal to the diameter of 25 when an arc is impinged upon a given point re- . the cylindrical type, is employed, is increased peatedly in a ceramic of this latter type„the approximately 300% over the area provided in heat builds up at that point and is not conducted a cylindrical type of switch of the same external away to any other portion of the ceramic. As dimension. 'I'his means that a material reduc ` this heat approaches a given point, the metallic tion inthe heating caused by the arcing pro 30 oxides in. this type of ceramic are reduced, and duced at the contact is effected, and also, currents the oxygen attacks the mercury and the unre of much greater capacity can behandled by a duced particles that spall oil' are floated on top~ switch of this present construction. of the mercury, or form an emulsion with thel .Referring now in detail _to the construction C: L: triethanolamine. Continued usagel of ceramics shown in Figure 2, this ilgure discloses a modified as of this type erodes a channel through the dam form of- switch in which the metal envelope I0’ is forming the retaining recess until the -retaining provided with a normally extending shoulder I2’ recess no longer is capable of retaining any mer and the cylindrical portion I3', the square shoul- ` cury. On the other hand, porcelain, being a der ll’pserving as an abutment for limiting the 40 good thermal conductor, no localized points’ of inward movement of the .ceramic I4'. The re 40 heating will build up, since the porcelain will maining details of the construction arev substan rapidly conduct the heat away from the localized tially as described in connection with Figure 1, point oi heat generation to all portions of the . ceramic, and this ceramic being in thermal con tact with the _metal envelope surrounding the -^ same, the heat will be readily dissipated to ad jacent portions of the switch. Also, it is to be noted that porcelain has a smaller thermal ex pansion than iron. Consequently, during oper the ceramic I4' being provided with a square type of'opening Il having> planar inclined runway surfaces, the ceramic Il’ being aligned with re 45 spect to the square portion III' of the envelope by means of the aligning pin 35 engaging in a suit-4 able recess formed in the ‘ceramic Il’. Similar reference numerals have been employed to indi ation of a switch in which the porcelain is dis cate similar parts of the construction. 50 As‘will be apparent from the structure shown posed in direct contact with the iron, any de velopment of heat will result in expansion of the in Figure 3, the body of mercury I1 moves up surrounding iron away from the porcelain. This lthe planar inclined surface I8 into contact with allows ñuid under pressure to enter the space the retained body of mercury 33 retained in the 'between the ceramic and the surrounding iron rectangular groove formed between'the face of envelope, consequently balancing the pressures the electrode 22 and the wall 20 deilnìng the sharp cutting edge I9 at the inner end of the _inclined tension stresses are produced which might tend surface I8. 'I'he entire width of the surface I8 is to crack the porcelain. therefore occupied by the advancing edge of the body of mercury I1, and the entire width of the 60 I iind that ample sealing is secured by employ ing a gasket having only a relatively short skirt or cutting edge- I9 is also contacted by the retained ilange 26, which seals the outerface of the por _ body o'f mercury 33.' Consequently, as the moving celain and4 yet does not confine any heating of body I1 moves into engagement -with the body 33, the porcelain so that dissipation is eliminated. two straight line contact surfaces are provided It is desirable that- any heat generated due to which materially increase the .contact area or arcing within the switch be dissipated as rapidly cross section of mercury coming into simultane ous contact. >T'his serves to reduce the resistance as possible through the porcelain to the enclos to making and breaking of the circuit, and at the ing metallic envelope. upon opposite sides of the ceramic so that nc By the use of a polygonal shaped envelope in 70 _which the body of mercury I1 is capable of mov ing, I provide .for a substantially straight line advancing edge of the mercury as it moves up same 'time providesv suiilcient mercury so that a ` much greater current can be controlled by the switch. ' - v , y n I have found that if the depth of the groove in war'dly over the inclined planar surface Il. l which the retained mercury 33 is disposed is not Similarly, the use of a square opening in the of a predetermined dimension', overheating will 75 ceramic permits the retained body of mercury occur due ‘to the relatively small contact area be-’ï 75S 4 2,132,922 tween the retained body of mercury 33 and the surface of the electrode 22 with which the mer cury is in contact. In order to prevent any such overheating and to insure that sufficient metal in to mercury contact is provided for all currents lwhich may be handled by the switch, I have provideda construction such as shown in Figure '1 `in which the ceramic 48 is provided with the rearwardly extending annular flange 42 defining with the inclined planar surface 43 a square shaped grooveextending about an annular groove v44. Within this’annular groove 44 I dispose a cup shaped electrode 45 'having the cylindrical flange portionv46 lying in and determining the outer periphery of the' groove. Disposed within the groove 44, and retained between the inner face of the electrode 45 and the inner defining wall of the groove is a body of mercury 41 which has a sub stantially increased contact area in engagement 20 with the surface of the electrode 45. Consequent ly, the mercury to electrode contact area is in creased to an- extent such that no overheating can occur because of the passage of higher cur rent of the body of mercury 41 to the electrode 45. '_I‘he electrode 45 is provided with a stud 48 ex tending rearwardly therefrom, and the usual re silient gasket 25 having the extending flange portion 26 is provided forvsealing the ceramic in position. 30 - - ' It is believed obviousthat the form of the electrode 45 may be -varied to a considerable de gree without departing from the underlying prin I. ciple'of providing an increased contact area »between the retained body of mercury and the engaged face of the electrode. An electrode of the type such as shown at 22 may, for example, be provided with a polygonal recess 2| cut into the face thereof at a point disposed adjacent'the retained body of mercury 33, so thata portion 40 of this mercury is capable of entering the groove to increase the contact area of mercury with the metal of the electrode. Considering now in detail the structure shown in Figures 4, 5 and 6, I provide a metal envelope having the square section 58, having the normally extending annular shoulder portion 52 and the enlarged cylindrical portion 53 within which is disposed a ceramic insert 54 having a square opening therein indicated at 55 which extends 60 substantially >flush with lthe level of the ñoor surface of the envelope 50 upon which the body of mercury 56 is disposed. The ceramic 54 is provided with an annular ñange portion 51 which receives the electrode 58, this electrode having a square head portion of reduced size indicated atV 59 and shown in detail in Figure 5. A resilient gasket 68 having the short skirt por tion 62 engaging about the annular ñange 51 is pressed into position by the compression washer 63 which is urged inwardly against the rear face of the gasket‘68. This seals the ceramic 54 with lrespect to the internal surface of the shell 53, '- and also seals the electrode 58 with respect to the flange 51 to provide a relatively long leakage 65 path between the electrode 58 and the interior surface of the shell portion 53. The reduced portion 59 of the electrode 58 is provided with curved surfaces 64 which are in the "form of meniscus curves, land provides for 70 full surface contact ofthe advancing straight edge A suitable contact lug retaining washer indi cated at 65 in Figure 6V is provided for disposition against the outer face of the compression washer 63, and is held in position- by the compression ring 66 formed of metal or the like, which is held in Ul position by the spun-over end 61 of the portion 53 of the metal envelope. The- contact lug re taining washer 65 is provided with a struck out tongue portion 68, which has a pair of curved formable ñnger portions 69 adapted to receive and engage the end of a conductor lead 10. A spacing bushing 12 is disposed within the opening 13 formed in the member 65, and 'serves to space a second insulating washer -member 14- from the spun-over end of the envelope, in order to in sulate the lead 18 from the other conductor lead 15 which is connected to a suitable lug 16 carried by the stud portion 11 of the electrode 58, the lug 16 being held in position by the clamping ' nut 18. 20 In the embodiment of the invention disclosed, the leads 10 and 15 come out from opposite sides of the switch, but it is obvious that, due to the provision of the insulating washer 14, the leads 10 and 15 can both come out at the same point in the periphery of the switch, if desired. The metallic switch envelope is venclosed in a suitable moldedphenol condensation product cas ing 88 which is molded to form and ñts rather snugly over the portion 50 of the envelope, and the 30 portion 53 thereof, extending to a point disposed ’ approximately in the` plane of the insulating washer 14. An end cap or mating closure mem ber 82 is provided which extends over the end of the stud 11 and encloses the contact lug 16 having a tongue and groove engagement indi cated at 83 with respect to the portion 80 of the enclosing casing, whereby the two casings may be cemented together. Each of the casings is provided with corresponding openings 84 and 85, 40 which serve as lead outs for the conductors ‘lli and 15, respectively. It is obvious that if the two conductor leads are toA be led out from the same portion of the casing, the closure member 82 will be rotated 180 degrees from the -position shown in Figure 4, whereupon the opening 85 will 45 be aligned with the opening 84 and the conductors 10 and 15 will be led out from the same side of the casing, being spaced by the insulating washer member 14. . The operation of the switch shown in Figure 4 50 is similar to that shown in the other figures, ex cept that a mercury to metal contact is provided instead of the mercury to mercury contact pro vided in the previous switch embodiment. It is, of course, obvious that the vinsulating enclosing cover formed by the members 80 and 82 can be - equally well applied to the switches shown in Figures 1 and 2, and will function in the same manner with respect to these switches as de scribed in connection with Figure 4. In such cases, the contact lug retaining washer 65 and the insulating bushing 12 will be applied vto the stud in order to provide for connection of the cor. ductors thereto. f . y Cl) (l5 Considering now in detail Figure 8, I have dis closed in this ilgure a switch member 98, pro vided with the insulating molded cover compris ing the two sections 92 and 93 corresponding to the members an and a2 of Figure 4, n1 this em 10 of the body of mercury 56 along the horizontal , bodiment of the invention,'however, the two con» portion of the curved surface 64 in order to in~ ductor leads 94 and95 are brought out at the same sure that the greatest cross sectional area of side of the housing through the aligned openings mercury will come into contact with the electrode 96. The switch of the disclosure shown in Fig 75 upon closing of the circuit. ure 8 is provided with a jacket member -91 which 15 _ 5 2,182,922 fits over the enlarged surface of the metallic en velope of the switch, the casing 92 being cut away for this purpose, and provides an annular space 98 _about >the reduced portion of the switch 3. A mercury switch comprising a square metal . envelope having an enlarged cylindrical end por tionvjoined thereto by a frusta-conical section, a ceramic insert in said enlarged portion having a envelope, which portion 98 is adapted to containV - frusto-pyramidal recess extending axially there a cooling liquid, such as water or _the like, in of, a disc-shaped electrode closing the small troduced through the conduit 99 and exhausted end of said recess and spaced therefrom to define through _the outlet |00 whereby this water may~ therewith a peripheral rectangular groove, a body circulate over the reduced portion of the switch of vmercury retained in the lower side of said 90 in order to dissipate heat therefrom. ` groove and having the meniscus thereof project ‘ It is therefore believed that I have provided ing above the edge of said recess for the full a switch construction which is capable of making - width of the small end of said recess, and a sec ' and breaking currents of considerably greater capacity than in any previously designed switch 15 of this type and which is capable of operating with a minimum of heating, since the contact area is increased to an extent such that a considerably greater cross sectional area of mercury comes. into simultaneous contact upon making of the 20 circuit, as compared to the point-to-point con tact ordinarily produced by rounded or curved surfaces. ' Also, by the use of a ceramic refractory which is heat conductive, and which has good thermal 25 contact with the metal envelope, I prevent any localized overheating of any portion of the switch, since the 'ceramic will conduct away the heat of localized arcs to the vswitch envelope. Other ond body of mercury in contact with said envel ope and movable along the lower side of said recess into and out of contact engagement with 15 said first body of mercury. 4. A mercury switch comprising a square metallic envelope having an enlarged cylindrical end, a thermally conductive refractory in said end in thermal contact with the interior of said en 20 larged end, an axially extending flange on the outer end of said refractory spaced radially in wardly of the end of said envelope, an electrode supported within said flange, resilient sealing ' means engaging the outer radial face of said 25 flange and electrode and having a peripheral flange portion disposed between said flange and the inner surface of said enlarged end of said features of my invention, such as the relatively l envelope,'a frusto-pyramidal recess in said re 30 long leakage path between the 'electrode and the metal shell, and the disposition of the ceramic in the shell in such manner that the sealing means applies only compressive stresses thereto, and no internal stresses upon the ceramic are set up, 35 are believed to provide a switch having greatly improved operating characteristics. While I am aware that various changes may be _ made both in the arrangement of parts and design of the structure disclosed, I- do not intend 40 to limit myself to the specific details shown and described, and my invention is to be understood fractory having its small end spaced from said 30 electrode by an inwardly opening groove, a body of mercury retained in said groove and present ing a contact surface extending parallel to the face of said electrode, and a body of mercury in said envelope movable along one surface of said 35 recess andhaving an advancing edge parallel to the contact surface of said first body of mercury. 5. A switch comprising a metal envelope hav-~ ing an enlarged lopen end portion, a ceramic in contact with the internal surface of said end por tion and having an axially extending flange at as limited only by the spirit and scope of the - the outer end thereof spaced inwardly of said appended claims. I claim: 45 « ' 1._ A mercury switch of the class describe _ having a pair of spaced electrodes, one of said electrodes _having a planar face portion, a recess having a transversely extending body of mercury in contact with said one electrode, a body of mer 50 cury in'contact with said other electrode and movable normally to said- face portion of said first electrode and a planar inclined floor leading from said other electrode to said recess, said last' named body of mercury being movable along said ñoor toward said ñrst electrode upon tilting of said switch with a straight line advancing edge extending parallel to said face portion and mov ing intosimultaneous full length contact with said transversely extendingbody of mercury. 2. A mercury switch of the class described have 60 ing a cup-shaped metal envelope, a ceramic in sert and an electrode extending normal to the axis of said envelope and supported solely by said insert, a body of mercury in contact with said envelope, a body of mercury extending par allel to one face of said electrode in contact therewith, and a planar runway formed in said insert between said bodies of mercury and a recess at one end of said runway retaining said 70 second body of mercury against movement and in transverse position across the'full width of said runwayv whereby said bodies of mercury . make and break contact between parallel faces surface, av disc-shaped electrode seated within said flange, and resilient sealing means engaging the outer radial surface of said electrode and said _ flange and having a peripheral axially extending flange disposed between the ceramic ñange and the internal surface of said end portion. 6. A switch comprising a metallic envelope, a thermally conductive ceramic in ‘one end of said envelope having thermal contact about its annu lar peripheralsurface with the internal surface of said envelope, an electrode supported solely by said ceramic and insulated thereby from said envelope, a body of mercury retained in contact with said electrode, a frusto-pyramidal recess lin said-ceramic extending outwardly from said retained body of mercury to the interior of said envelope, and a body of mercury in said envelope movable along a deñning surface of said recess 60 into and out of contact with said retained body of mercury. . 7. A switch comprising Va metallic envelope having an enlarged cylindrical end portion, a ceramic insert'therein having an axially extend ing annular ñange spaced radially inwardly of the interior of said enlarged portion of said enve lope, an electrode disc seated within said flange whereby the leakage distance from said disc to said envelope includes at least' two surfaces of 70 said ñange and the radial distance from said flange to the interior of said enlarged end of said _ envelope, and resilient sealing means enclosing extending substantially the full width of said- `the outer face of' said electrode `anddlange and having a peripheral flange portion disposed be 75 runway. l2,132,992 6 tween` said ceramic iiange andthe interior of said envelope. ,l Y 8. A switch comprising a metallic envelope, a. trical engagement with ysaid envelopera'n elec trode carried by said insert and having an axially projecting stud, a terminal lug on said stud, con ceramic ein one end of said envelope having ther-¿ ductorîs connected to said washer and said lug, ` 5 mal Contact about its peripheral surface with? insulating spacing means on said stud separat- 5_ the interior of said envelope, an electrodejcarriedn ing the ends of said conductors, and atwo-piece _ by said ceramic and radially insulated j‘jhereby,? ‘moulded housing enclosing said switch and hav ing adjacent openingsrrin theirY meeting edges for and resilient‘ïsealing means comprising a disc . ' like member having a peripheraì iiange disposed? leading out saidconductors. 1,5. 'I'he combination with a metal envelope 10 mercury switch of the class described having a 9. In combination, a switch comprising a pair of conductors connected to the envelope and `metallic envelope, a disc-shaped electrode dis-I to arrVY electrode carried by and insulated from said -posed in insulated position in one end of said envelope, of a housing for saidswiteh compris 15*V envelope and extending? transversely across said ing a first moulded part enclosing ogre end and 15 envelope, a planar` insulating runway-ï between the major lateral periphery of the envelope, and said electrode and the interior surface of said a second ‘moulded part enclosing the other end envelope, and a body of mercury movable along ' of said envelope andY having keying engagement said runway upon tilting of the envelope toward at its edge with> said first part, and? individual openings in each part adjacent the meeting edges 2o è 20 said electrode and having a straight line advanc thereof whereby said conductors may be 'led out ing edge extending transversely across said run way normal toethe’direction of movement of said from said switch in? any desired angular rela l0 about Ythe radially insulated part V9i said »,electrode. g - tion; Y e '- i j, . mercury. 10. A switchcomprising i; a metal envelope hat; 25 ing a ceramicrinsert seated in one end thereof, 16. A contact lug retaining washeg adapted to be compressed between the spun-over edge of a 25 ' said insert carrying at its outer end are electrode . metal envelope and the ceramic insert in a mer radially insulated thereby from saldi-envelope, 'cury switch Yof the class described,-r comprising a resilient sealing means closing the insert end of said envelope about-said electrode and radially overlapping said oneí end off said insert, and means for axially compressing said sealing means washer-like ring having an integralY radial pro- i jection provided at its free end with lateral pro jecting ears, said ears being bent over to form a 3Q; in position whereby said insert isV entirely under over toy dispose' the axis of said socket in a plane conductor socket and said projection being?bent sulïstantially parallel to the plane oi said washer. 17. In combination, a metallic switch envelope switch havingf a square envelope section and an ' having a body portion 'andan enlarged end por- 35' enlarged cylindrical end portion, of ïa ceramic tion defining therebetweenêan annular shoulder, disposed in said enlarged end; portionî having an a ceramic insert in said end portion having its axially extending outwardly projecting iiange, an inner end seated against said shoulder to limit annular shoulder spaced radially inwardly of said inward movementfof said insert, an axially vex compressive stress. l 'e ¿e 11s-The combination, in a metal Venvelc'gie 40 ñange, and a frusto-îoyramidal recess extending from the inner. end of said ceramic toward said shoulder and@ having? its small end terminating radially inwardly of said shoulder andrspaced axi ally Èinwardly thereof. , ' i i2'.Y A ceramic insert for a mercury switch of the class described comprising a thermal con tending ñange on Vthe outer end of- said insert ¿g spaced radially inwardly of the interior surface ofE the end portion of said envelope, an axial bore in said insert terminating at its outer end in successive "annular shoulders, an îelectrode disc disposed :within said ñange andseating against 45 i one of said shoulders to limit inward movement ductive refractory having an axially extending ~thereof, and resiiient sealing .means having‘a disc-'shaped portièn engaging the nouter faces of irusto-pyramidal recess in one end thereof 'ter minating inwardly ci’ said end in a rectangular said electrode andñange and havinga peripheral radial groove of a depth and width suchras to flange extending into the annular space jbetween 50 50 retain a stable body of mercury therein, said said end portion of said envelope'and sai î?ñange i `groove. having the side away'from "said recess ci’ said insert. defined by the planar face of an electrode Ísup ported entirely in the .opposite end of îrsaid ceramic. Y « fY ' i3. In combination, a metal envelcîpe switch oi' the class described? havingja ceramic insert in one end thereof, sealing means for the outer end ‘ci said insert, `a compression ring engaged bythe 60 spun' over end of said envelope for pressing said sealing means against said insert, a contact lug washer held in position by said ring and ingelec trical engagement ?with said envelope, anfrelec trode carried by said insert, a ccnductorîoon ($5 nected to said washer, a conductorgconnected to said electrode, a spacing insulatorïbetween said conductors and carried by sacïid electrode, and a two piece moulded?housing enclosing said switch 18. In combination, a metallic switch envelope having aîiody portion and an en_îarged end por tion deñning therebetween an annular -shoulder, 55 a ceramic insert in saidî end portion having its inner end seatedî against said shoulder to limitl inward movement of said insert, an axially. ex tending "iiange on the outer end of said inserti spaced radially inwardly lof the interior surfacei 30 of the end portion oi said envelope, an axial bore said insert terminating at its outer end in suc cessive annular shoulders, an electrode disc dis posed within said flange and seating against one of said shoulders to limitï inward movement there- 65 of, resilient sealing means having a disc-shaped portion engaging the outer faces of said electrode and ñange and having a peripheral iiange ex and having an annular joint provided with open- i tending’Y into the annular space between said ene't 70 ings for leading out said conductors radially oi said joint; È14g. In combination, a metal envelope mercury portionîof said envelope and said ñange of said 70 insert, and a relatively rigid insulating ~disc com pressed against the outer radial face of said switch having a ceramic insert in ?one endgthere. ' sealing _means to produce axiaigand radial com of, compression means for holding saidl insert in pression oi said sealing means on said ñange position including a-terminal lug `easherin elec and electrode. 75 ananas 7 19. In combination, a metallic switch envelope having a body portion and an enlarged end por projecting radially inwardly beyond the adjacent ` `tion defining therebetween an annular shoulder, and an axial recess in the face of said electrode edgeof the lower defining surface of said recess, a ceramic insert'in said end portion having its inner end seated against said shoulder to limit inward movement of said insert, an axially ex tending ilange on the outer end of said insert receiving a portion oi said mercury to increase the area of contact between said mercury and said electrode. 22. In combination, a metal envelope switch of the class described having a ceramic insert in spaced radially inwardly of the interior surface of the end portion'of said envelope, an axial bore one end thereof, sealing means for the outer end of said insert, a compression ring engaged by the spun over end of said envelope for pressing said sealing means against said insert, a contact lug 10 in said insert terminating at its outer endin Asuc cessive annular shoulders, an electrode disc dis ' posed within said ilange and seating against one x of said shoulders to limit inward movement there washer heldin position by said ring and in elec of, said disc having an axial thickness such that the outer radial face thereof is coplanar with the outer end of said ilange, and resilient sealing means having a disc-shaped portion engaging the outer faces of said electrode and ilange and having a peripheral flange extending into the 20 annular space between said end portion of said envelope and said ñange of said insert. 20, In combination, a metallic switch envelope trical engagement with said envelope, an elec-' trode carried by said insert, a conductor con 15 nected to said washer, a conductor connected to said electrode, and a spacing insulator between said conductors and carried by said electrode. - 23. In combination, a metal envelope mercury switch having a ceramic insert in one end there 20 of, compression means for holding said insert in position including a terminal lug washer in elec having a lbody portion of square form and an trical engagement with'said envelope, an elec enlarged cylindrical' end defining therebetween a trode carried by said insert and having an axially 25 shoulder, a ceramic insert having its inner end projecting stud, a terminal lug on said stud, con 25 seated against said shoulder, a frusto-pyramidal` ductors connected to said washer and said lug, recess in said insert, means foraligning said in and spacing means on said stud separating the sert with said envelope to maintain the defining ends of said conductors. surfaces of recess in register with the interior 24. In- a metallic envelope type of mercury 80 deilning surfaces of said body portion,- an elec switch, a ceramic insert having a frusta-pyram trode supported in said insert at the end of said idal bore extending axially ‘therein and termi recess removed from said body portion, and ‘a nating at its smaller end in an acutely angled body of mercury in said body portion _and mov straight line transverse cutting edge extending able along the lower deilning surface of said re the width of said smaller end, a radially out- . cess with an advancing edge extending normal to wardly extending wall defining said edge, an axial the direction of movement thereof toward and wall disposed at the outer end of said radial wall away-from said electrode. ’ ï extending parallel to said edge, a second radially » 21. In a `metallic envelope type of mercury switch, a ceramic insert havinga frusto-pyram 40 idal 'recess terminating at its small end in a outwardly extending wall at the opposite end of said axial wall, and a planar disc-shaped elec trode seating against said second radial wall and 40 rectangular radially offset groove, an axially ex- , extending parallel to said ilrst radial wall to tending annular flange on said insert disposed denne Ywith‘said last-named wall and said axiall radially and axially outwardly of said groovefa wall a rectangular groove extending the full. disc-shaped electrode seating in said flange and width of the smaller end of said recess. 45 forming'one deilning wall of said groove.' a body of mercury in the lower side of said groove and ' PAUL S. BEAR.