US2436602A - Timing switch - Google Patents

Description

' Feb. 24, 1948. R KMEYER 2,436,602

TIMING SWITCH Filed Nov. 12,1946 I s Sheets-Sheet 2 Ernst; Walfer Rick meyer id wa Feb, 24, 1948. E. w. RlCKMEY-ER TIMING SWITCH Filed NOV. 12, 1946 3 Sheets-Sheet 3 .76 M Z 4 3 Q v// 0///WI////////, 3% a v i; fiiderz 2'07" 22-2156 'falter'al'cimezyer Patented Feb. 24, 1948 TIMING SWITCH Ernst .Walter Rickmeyer, Berkeley, 11]., assignor to Jefferson Electric Company, Bellwood, 111., a corporation oi Illinois Application November 12, 1946, Serial No. 709,151

24 Claims. (01. zoo-s) The present invention relates to means for regulating the passage of a fluid under pressure through a member which is capable of acting as a partition under low pressures of the fluid thereon but which will pass the fluid under high pressure. It is particularly applicable to centrifugal switches wherein a conducting fluid (mercury) is moved under pressure developed by the centrifugal force resulting from high speed rotation. A type of switch to which my invention is applicable is shown in my application Serial No. 530,123, filed April 8, 1944, for Switch.

In the switch shown in the above identified application one contact memberis a metal shell. A second contact member. is mounted in one end of the shell and insulated from it. The shell is divided into two chambers, one containing the second contact member. The partition separating the two chambers provides restricted passage for a quantity of conducting fluid (mercury) whereby upon rotation of the shell about an axis at one side of the partition centrifugal force will tend to move the fluid through the partition from one chamber to the other. When the chambercontaining the contact is filled with the fluid and the inner end of the second contact extends into the shell 2. definite distance, the time it will take to open the circuit between the shell and the second contact member after rotation begins is determined by three factors.

These are, the pressure against the partition due to centrifugal force, the resistance to flow of the fluid due to the nature of the passageway through the partition, and the volume of fluid that has to be moved through the partition touncover the end face of the second contact member.

It is the purpose of my invention to provide meanswhereby accurate efiective control of the resistance to passage of the mercury through a member, such as the partition above referred to, may be obtained.

Another purpose of my invention is to provide a partition member made in predetermined 2 mediate the ends of the shells, in a switch of this character, by the utilization of a body of porous material having relatively high impact strength in conjunction with a non-porous support that may be provided with one or more apertures to be covered by the porous material, The strength of the body of porous material is such that it needs no bracing or containing cover to keep the mass of the body together under the pressures to which it is subjected.

It is also a purpose of my invention to provide a novel restriction member adapted for use in a partition through which mercury is to be forced by centrifugal action, which restriction member is composed of a. sintered mass of particles of metal having a uniform range of particle size and substantially devoid of fine particles that will wedge in and fill the voids between the particles within the range of which the mass is made.

It is a further purpose of my invention to provide a restriction member composed of a uniform range of particle size of powdered metal wherein the metal is pure nickel and has a limited but dtfinite afiinity for mercury.

Another purpose of my invention is to provide novel means whereby a restriction member of the .character described may be mounted in a shell and have sufficient tensile and impact strength to form .a part of the partition between two ends of the shell, at least one end of which has therein a contact member.

- thickness out of finite small particles ofmetal so adhered together as to provide a multitude to withstand sharp impacts and; to withstand machining to accurate thicknessi' It is also a purpose of this invention to provide a' novel means whereby a multiplicity of very fine restricted passages may be formed inter- Other obiects and advantages of the inventicn will app-ar as the description proceeds, reference being bad to the accompanyQng drawings wherein a preferred form of the invention is shown. It is to be understood however thatthe drawings and description are illustrative only and are not to be taken as limiting the invention except insofar as it is limited by the claims.

In the drawings:

Fig, 1 is a plan view of a rotating device showing a switch embodying my invention mounted therein; I i

Fig. 2 is a longitudinal sectional view through a switch embodying my invention;

Fig. 2;

Fig. 4 is a longitudinal sectional view through a switch of a slightly difierent form embodying my invention;

Fig. 5 is a sectional view on the line 5-5 of ,Fig. 4;

Fig. 6 is a longitudinal sectional view through a switch wherein arestriction member embody aaaaooa ing my invention is provided in a protected wafer form mounted in a switch shell;

Fig. '7 is a sectional view on the line 'l--1 of Fi 6;

Fig. 8 is a longitudinal sectional view through a switch embodying my invention and having a modified form of shell constructon;

Fig. 9 is a sectional view on the Fig. 8;

Fig. 10 is a view like Fig. 8 but showing a further modification;

Fig. 11 is a sectional view on the Fig. 10;

Fig. 12 is a longitudinal sectional view through a switch embodying still a further modification of the invention; and

Fig. 13 isasectional view through the switch taken on the line l3-l3 of Fig. 12.

The present application is a continuation in part of the copending application Serial No. 53.4,- 446, filed May 6, 1944 now abandoned.

Referring now in detail to the drawings, the present invention concerns itself with a switch I2 which as shown is mounted in a rotating member 13 which may be carried by any suitable means such as a shaft of a motor (not shown). The opening [4 in the member 13 may be utilized to mount the member on the shaft.

I have hereinbefore described the type of switch to which my invention is particularly applicable. Such a switch is shown in Fig. 2 wherein the numeral l represents a metal shell made of steel, copper or other suitable metal. This shell has an end portion l6 reduced to provide an annular shoulder at II. In this form of construction the shell has a cup l8 seated therein, the cup being composed of a material which is effective to provide, by means of its bottom wall, a partition l9 which separates the shell l5 into two chambers 20 and 2|. In order to close the chamber 20 and to mount a contact member therein I provide a suitable contact member 22 which may also be made of steel, stainless steel or copper. The contact member 22 is mounted to theshell by two insulating washers 23 and 24. As shown, the contact member has a shoulder at 25 against which the washer 23 rests. A reduced portion 26 of the contact member is hollow and extends through the washers 23 and 24 and through a. terminal 21, the end of the reduced portion being spun over as indicated atv 28 to bind the assembly together. The insulating washer 23 is seated within the shell I! on top of the cup 18 and the open end'of the shell is spun over as indicated at 29 to secure the parts in position. The insulating washers 23 and 2d may be made of any suitable material such as polystyrene. In the switch as described the shell 15 forms one contact member while the other contact member is the member 22. When mercury is placed in the chamber 20 it establishes a conducting path between the shell I5 and the member 22,- provided the cup I8 is of electrically conducting material.

My invention primarily concerns itself with making the base portion 19 of the cup with a multitude of very fine passages which are caps.- ble of passing the mercury when it is pressed against the base with sufiicient pressure. The

line 9-9 of line I l-li of construction of the base portion is should be such however as to prevent flow of mercury from one chamber to another under the normal weight of the mercury and even under continuous or intermittent jolting such as might occur in transportation and rough handling. In switches of this character it is essential also that the material be capable of withstanding the relatively high pressures developed by high'speed rotation. It must not crack or break under impact shocks because the switches are sometimes started to rotate very suddenly and the initial blow of the mercury against the wall l9 then is in the nature of a sharp impact. According to my invention I make the cup H! of a powdered metal of selected particle size so as to give a definite porosity or passage area through the base I9. The powdered metal is first graded to a definite range of particle size; for example, particles ranging from 60 to mesh, 80 to mesh, or 100 to mesh for certain applications. For other applications a much closer control of particle'size (for example all mesh) may be necessary. In other applications where extremely high pressures are used a variety of particle sizes ranging from relatively large particles, such as 100 mesh, to fines may be necessary.

It is essential that the powdered metal be of certain characteristics with respect to mercury in order to function. The well known afiinity of mercury for such metals as silver, copper or gold rules these metals out because the mercury would soon amalgamate with them and destroy the operability of the device. I find that the ideal combination is a metal having a very low but definite aflinity for mercury whereby its surface can be wetted by the mercury without too great difiiculty. It must not ,be repellent to mercury because that also would adversely affect the switch. Pure nickel powder .is advantageous because it has the desired affinity for mercury. It also is highly resistant to corrosion and in addition it may be readily welded to steel. Other metals that may be used are tantalum and columbium. These metals have a very low afilnity for mercury and in addition are quite corrosion resistant. Columbium however is not quite as good in this respect as tantalum. I find that I may use iron but it is objectionable on the ground that it rusts readily. Furthermore, it is dimcult to get the fines out of. the iron powder. It is also diificult to get uniformity of porosity. The iron does have the advantage that it can be readily welded.

In preparing the powdered metal unit 18 the screened powdered metalof selected particle size is first formed into wafers or cups of a definite thickness under a predetermined pressure to obtain the desired density. Larger particle sizes, generally speaking, will provide greater porosity in the wafer. When the units are formed they are sintered in a non-oxidizing atmosphere such as a hydrogen atmosphere to a temperature just below the melting point so as to cause the particles to adhere firmly together. This sintering is actually a sweating action whereby the material becomes a unitary mass because all of the particles stick to each other. Any foreign material having a lower melting point is also burned out by this sintering action. The units can then be heat treated to give the desired hardness and cooled in a non-oxidizing atmosphere to avoid oxidation. The necessary characteristics of the units are that they shall be tough enough to withstand high pressure and sharp impacts and be capable of being machined, if necessary, to provide smooth surfaces and accurate dimensions.

I find that when the cup 18 is constructed in the above fashion'the base portion l9 may be used as a means to provide the necessary restricted passageways for the passage of mer- 36 has its end 3! rolled in over the wafer 35.

aesaeoa cury between the chambers "and 2]. Normally if the cup ismade of material having the characteristics hereinbeiore described it will retain the mercury in ordinary; handling onone: side of the partition, and} when subjected to high pressure due to centrifugal force, it will allow the mercury to pass at adeflnite rate from one chamber to" the other. This type of restriction .member is particularly 'advantageous since the porosity can be controlled in production on a quantitybasis andisentirely independent of the shell construction or the mounting of the cup therein.

Referring now to Figs.4l and 5, in' this form of the invention I have shown means whereby a shell [5 essentially likethe shell of Fig. 2 can be provided withan oriflce carrying'disk 3? which has a small orifice-3| therein. This disk is welded in 'positionagainst the shoulder I! as indicated. at 32 andserves as asupportfor a sintered metal}; 2 wafer 33. The wafer 33 is constructed like the cup I3. I find however that with the wafer it is essential to provide some means to prevent leakage between its periphery and the shell itself. In order tomaintain accurate spacing be- 2 tween the wafer 33 and the contact member 22 I provide a sleeve 34. This sleeve can be of varying thickness in order to control the volume of the chamber surrounding the contact 22. The contact 22 and its supportinginsulating washers 3 are constructed in the same fashion as in Fig. 2 and are secured againstthe end face of the sleeve 34 in the same-manner as they are secured against the face of the cup IS in Fig. 2.

In Figs. 6 and 7 of the-drawings the modifica- 3 tion shown isparticularlyuseful in avoiding difficulty due to leakage. A sintered metal wafer 35 is mounted in a steel orifice cup 36. The cap predetermined size: in order to uncover a certain area of the wafer 36. This form'of switch has the wall of the cup 36 welded tothe shell 15 as shown at 39. Except for the-construction 'pointedout above, this form of the device is es- 4 sentialiy the same asthat shown in Figs. 4 and 5.

The sealing of the water in the cup 33 is done before inserting the cup-in the shell IS. The cup presents a 80.011 surface to weld to the shell l5so theresis les's leakage and the sintered metal 5 wafer is protected by the cup. 7

In switches of the character described herein a one of the critical dimensions is the distance from the end face of the-contact 22 to th'esurface of the restriction forming member. This 5 dimension is accurately controlled by the cpnstructions' shown in Figs. 8' to 11 of the drawings. In these figures a metal shell 40 is drawn 'to the cup shape shown with a bottom part 4l aperturedto receive the-center contact 22'. Ad- 6 Jacentto the part 41 the shell has a section 42 and beyond this. a section 43 of larger diameter than the section 42; The junction of the sections 42' and 43 provides a shoulder 44. A powdered sintere'd metal disk 45 is placed against 6 the shoulder 44. Then an orifice washer 46 is seated on the di'sk:45 and welded to the wall of the section 43 as shown at 41. The washer 45 has an orifice 48 therein of a predeterminedcross section. The center contact 22 is fastened to 7 the bottom portion M by utilizing a series of insulating rings"; 50, 51 and 52 betweentheshoulder 25 and the contact'terminal 21.

The depth of the cup 43' from the bottom por- 6 accurately in production. Also, the length of the contact member "from the bottom 4| to the tip oi'the contactcan be controlled quite accurately. Thus the distance from the contact 2! to the 5' restriction forming sintered metal disk 43 is easily maintained. v

Two simple methods of closing the end of the shell section 43are illustrated in Figs. 8 to 11, inclusive. In Figs- 8 and 9 a spacing sleeve 53 is placed in the section 43, then a closing disk 54 is placed against the outer end of the sleeve and the end' of the shell section 43 is spun over the disk 54 as shown at 55.- The diskv 54 is welded tothe shell sections 43 as shown at 56. In Figs. 5 10 and 11 a cup 51 is seated in the open end of dicated at 5B.

The escape of mercury from one chamber to the other in this switch must be confined to 0 passage through the predetermined orifice. If not, the rate of escape will not be sumciently uniform for most purposes; That is why so much care is taken in the devices shown in Figs. 4 to 11, inclusive, to weld, the orifice containing members.

In Fig. 12 of the drawings a. further modification of the invention is shown. In this embodiment'a shell is provided with a restricted end portion Bl which provides a seat at 62 for an 0 orifice containing disk 63. The disk 63 has an orifice 64 of predetermined cross section area therein. The 'disk 63 provides a partition separating the shell into two chambers'65 and 66. The shell also has a center contact 61 extending 3 into it from one end thereof, the center contact being mounted upon an insulating washer assembly consisting of two washers 68 and 69. A terminal III is secured with the insulating washers I to the center contact by spinning over the outer base ofthe cup 33 has an aperture 38 therein of 40 end of the center contact.

In this form of the invention a powdered sintered metal wafer 12 is utilized as a restriction member to limit the flow of mercury from the chamber 66 to the chamber when pressure is 5 applied by setting up a centrifugal force axially o the shell due to rotation of the shell in the manner described. The 'sintered. metal wafer 12 is seated ina recess 13 provided in the disk 63 and is held in this recess by turning over a 0 portion of the metal around the periphery of the recess as indicated at I4.

It lis well known that steel alone is a poor electrical contact. Likewise mercury in contacting steel does not make a very ood electrical con- 5 nection. .In order to overcome this diificulty a sleeve 15 of copper is provided within the shell 60. This copper sleeveserves as supporting means for the insulating washer 68 and furthermore, as

to determine the fspacin'g between the contact 81 and the restriction member 62. the sleeve 15 will amalgamate slowly with the mercury but the rate of, amalgamation is such that it will not affect the characteristics of the p 5 mercury adv rsely during the time the switch must be in u e. ,This construction is particularly applicable to a one-time operation switch which' a spacer between the disk 63 and the washer 68 The copper of will be operated within ar'reasonable time after I it is produced. In order to further establish a 0 means of producing better contact between the shell and the sleeve 15 the sleeve 15 is driven into the shell and before being driven into the shell is coated with mercury on its surface, thus providing a copper mercury amalgam surface tion 4| to the shoulder 44 can be controlled quite that will provide an extremely uniform condi- 7 tion of engagement between the copper sleeve and the steel shell. The center contact 61 is desirably of a material having good conducting characteristics.

The foregoing description is believed to be sufficient to enable those skilled in the art to practice the invention. forming and mounting the powdered sintered metal restriction forming members has been explained. The advantages of such members are believed to be clear.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a device of the character described, a pair of chambers, a quantity of mercury in one of said chambers, and partition means between said chambers having at least a portion thereof provided with a multitude of fine passages capable of substantially retaining mercury on one side of the partition in normal handling and capable of passing the mercury when it is subjected to high pressure tending to force the mercury through the partition, said portion comprising a thickness of powdered metal sintered to cause the particles to adhere to each other.

2. In a device of the characterdescribed, a pair of chambers, a quantity of mercury in one of said chambers, and partition means between said chambers having at least a portion thereof provided with a multitude of fine passages capable of substantially retaining mercury on one side of the partition in normal handling and capable of passing the mercury when it is subjected to high pressure tending to force the mercury through the partition, said portion comprising a sintered wafer of powdered metal.

3. An article of manufacture for use in a mercury switch having a switch envelope having an apertured wall dividing the envelope into two chambers, a restriction member for covering the aperture, comp-rising a porous wafer of powdered metal having a low affinity for mercury.

4. An article of manufacture for use in a mercury switch for dividing a switch envelope into two chambers, a restriction member, comprising a wafer of powdered metal having a low affinity for mercury, and a supporting member of non-porous material for said wafer, said supporting member having an orifice therein covered by said wafer.

5. In a centrifugal type switch wherein mercury is the movable contact element, two chambers, a quantity of mercury in one of said chambers, and restricting means interposed between said chambers to retard the flow of mercury from one chamber to the other. said restricting means comprising a layer of powdered sintered metal.

6. In a centrifugal type switch wherein mercury is the movable contact element, two chambers, a quantity of mercury in one of said chambers, and restricting means interposed between said chambers to retard the flow of mercury from one chamber to the other, said restricting means comprising a layer of powdered sintered nickel.

7. In a centrifugal type switch wherein mercury is the movable contact element, two chambers, a quantity of mercury in one of said chambers, and restricting means interposed between said chambers to retard the flow of mercury from one chamber to the other, said restricting means comprising a layer of powdered sintered iron.

8. In a centrifugal type switch wherein mercury is the movable contact element, two chambers, a quantity of'mercury in one of said cham- The particular manner of bers, and restricting means interposed between said chambers to retard the fiow of mercury from one chamber to the other, said restricting means comprising a layer of powdered sintered metal of substantially uniform particle sizeand density.

9. A switch comprising a tubular metal shell, 9.

contact member extending into said shell from one end and insulated therefrom, the shell comprising a second contact member, a body of mercury in the shell, said shell having partition means therein spaced from the contact member and dividing the shell into a chamber containing said contact memberand a chamber remote from comprising a layer of powdered sintered tantalum.

11. An article of manufacture for use in a mercury switch for dividing a switch envelope into two chambers, a restriction member comprising a partition wall section composed of united fine particles of material of substantially the same size, said wall being of the same thickness throughout whereby to provide uniform porosity throughout the area of said section.

12. An article of manufacture for use in a mercury switch for dividing a switch envelope into two chambers, a restriction member comprising a partition wall section composed of united fine particles of material of a specific size range, the upper and lower limits of which substantially eliminate particles fine enough to fit within the I voids formed by engagement of the larger particles of said size range with each other.

13. An article of manufacture for use in a mercury switch for dividing a switch envelope into two chambers, a restriction member comprising a partition wall section composed of a coherent mass of metal particles adhering directly to each other, said metal particles being of a variety of sizes, the upper and lower limits of which are far enough apart to cause finer particles to fit within the voids formed by engagement of the larger particles of said size range with each other and thereby interlock-the larger particles. I

14. An article of manufacture-for use in a mercury switch for dividing a switch envelope into two chambers, a restriction member comprising a partition wall section composed of a coherent mass of nickel particles adhering directly to each other, said nickel particles being of a specific size range, the upper and lower limits of which substantially eliminate particles fine enough to fit within the voids formed by engagement of the larger particles of said size range with each other.

15. A switch comprising a tubular metal shell. a contact member extending into said shell from one end and insulated therefrom, the shell comprising a second contact member, a body of mercury in the shell, said shell having partition means therein spaced from the contact member and dividing the shell into a chamber containing said contact member and a chamber remote from the contact member, said partition means comprising .a porous water of powdered, sintered metal particles-adhered to each other with sufficient'bond to be machined and to withstand fllistantialpressure strains and impact shocks;

16. A switch comprising a-tubula1metalshell. a contact member extendinginto said shell from one end and insulated therefrom, the shell cum prising a second contact member, a body of mer cury in the shell, said shell having: partition means therein spaced. from the contactmember and dividing the shell into achambcr containing said contact member and a chamber remote from the contact member, said partition macaron prising a porous wafer of powdered sintered metal particles adheredto each other with sum cient bond to be machined and to withstandsubstantial pressure strains and impact;

a non-porous metal orifice member on which said 1c, mercury 'inohc chamber, the partition means 10 partition means including a porous wafer of powdered sintered nickel particles adhered to each other with suflic'i'ent bond to be machined and to withstandsubstantial pressure strains and impact shocks {ands body of mercury in the cup be-- tween the partition wall and the bottom of the glgc up.

-"-the'shell spaced from the shell ends reyide two chambers, a quantity of having at least a portion thereof provided with a v;inultiiaiile of fine passages capable of passing mercury when it is subjected to pressure sum-- Ljciehttb force-the mercury through'the partition into the second chamber, apair of spaced 8180-? Water lssecured, saidorifice member' -having at'f least one aperturettherein.

17,-A switch comprising a tubulanmetaiwshell, .a contact member extendinginto said 'shellfrom one end and insulated therefrom, the shell com prising a second contact member, a body of mercury in the shell, sald'shelI havinI-partition means therein spaced 'from the contact mem. her and dividingthe shell into a chambcr containing said contact member and a chamber remote from the contact member, said partition means comprising a porous wafer of powdered sintered metal particles'adhered to each other with suflicient bond to be machined and to withstand substantial. pressure strains and impact powdered sintered metal providing passages through the partition, and a body of mercury in sintered tocause theparticles to adhere to each :trical r'c'ontact members adapted to be electrically connected by the mercury when the latter is disposed in. onect the chambers, said partition portioncomprising a thickness of powdered metal other. v 1 22. In a switch-of the character described, a

' tubular shell, mercury in the shell, a center contaclicxtending intosa-id shell at one end thereof,

means mountin'g' said contact on said end of the a shell and insulating the Jcontact from the shell, a cup in said shell having a recessed and aperswitch, comprising a shell, partition Y tured bottom dividing the shell into two chambers,

and a porous wafer seated in said recess so as to providearestricted orifice in the cup bottom which passes mercury under high pressure but 7 preventspassage of mercury at atmospheric pressure under jolts, impacts, and the like, incident to handling. 23; In a switch of the character described, a

' tubular shell, mercury in the shell, a-center con- .tact extending into said shell at one end thereof,

meansmounting said contact on said end 0! the shell and insulating the contact from the shell, a partition spaced from said contact in said shell, said partition including means providing a restricted orifice which passes mercury under high pressure but prevents passage of mercury at atmospheric pressure under jolts, impacts, etc. incl- .dent to handling, a cup in said shell having a thecup between the partition wall andthe bottom I J of the cup.

19; A switch comprising a metal cup having an opening in the bottom thereof, a contact member extending into the cup through the bottom opening, means sealing the bottom of the cup liquid-tight and electrically insulating the, contact member from the cup walls, partition means in the cup spaced from the contact member, said partition means including a porous water of powdered sintered metal particles adhered to each other with sufllcient bond to be machined and to withstand substantial pressure strains and impact shocks, and a body of mercury in the cup between the partition wall and the bottom of the cup.

20. A switch comprising a nickel cup having an opening in the bottom thereof; a'contact member extending into the cup through the bottom opening, means sealing the bottom oi the cup liquid-tight and electrically insulating the contact member from the cup walls, partition means in the cup spaced iromthe contact member, said recessed and apertured bottom, said restricted Orifice means comprising a porous wafer .of

powdered sintered metal seated in said recess.

24. In a switch of the character described, a

tubular shell, mercury in the shell, 9. center contactextending into said shell at one end thereof,

means mounting said contact on said end of the shell and insulating the contact from the shell, a partition wall spaced from said contact in said shell, said partition wall being provided with an I aperture therethrough, a recess in said wall adja cent to the aperture, and a porous wafer of powdered sintered metal seated in said recess and covering said aperture.

ERNST WALTER RICKMEYER.

, REFERENCES CITED The following references areof record in the file of this patent:

UNITED STATES PA'I'ENTS Name Number Date 2,414,836 Rickmeyer Jan. 28,1947

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