US2435533A - High-voltage circuit interrupter - Google Patents

Description

Feb. 3, 1948. R. EARLE 2,435,533

HIGH VOLTAGE CIRCUIT INTERRUPTER Filed March 6, 1944 2 Shecs-Sheet 2 W. r 9 v z a w m m mf A770 Alf). g

V 5-? M 4 n. 3 2 I 7 I: ,6? l 1 J j N/lm J1 /////////////////////A Patented Feb. 3, 1948 2,435,533 HIGH-VOLTAGE cmcurr INTERRUPTER Ralph H. Earle, Wauwatosa, Wis., assignor to Line Material Company, South Milwaukee, Wis., a,

corporation of Delaware Application March 6, 1944, Serial No.-525,1 59

This invention relates to high voltage circuit interrupters.

Objects of this invention are to provide an interrupter which is capable of interrupting high voltage, heavy duty circuits, which rapidly ex tinguishes the resulting arc in an effective and reliable manner, and which is so constructed that the major portion of the device may be used over and over again.

Further objects are to provide a high voltage, heavy duty drop-out circuit interrupter in which means are employed, such as a fuse tube for instance, to provide an arc channel in which a fusible link is located, and to provide means for forming a power or main are when the circuit is overloaded and forming an auxiliary arc in series with the main arc and drawing the auxiliary are into proximity to gas evolving material, the construction being such that a blast of gas is blown axially of the arc channel to extinguish the main arc and to simultaneously elongate the auxiliary arc to prevent the restriking after the main arc has been extinguished.

Further objects are to provide a circuit inter rupter which is so constructed that it will efiec tively interrupt the circuit for a relatively small overload or for a relatively large overload or for any intermediate value of overload with equal certainty of operation in each case, and which is so made that the building up of excessive pressure in the arc channel is prevented. In greater detail, further objects are to provide a high voltage, heavy duty fuse construction in which an expellable apertured plug is provided in which the main arc is formed and through which a blast of gas is projected to extinguish the main are upon the rupture of the fuse link on moderate overload, with the plug so arranged that it is expelled on heavy overload to provide a larger discharge passage for the gas to there: by prevent building up of excessive pressure in the device.

Further objects are to provide a fuse construc{' tion in which means are provided for liberating arc extinguishing gas in one portion of the fuse tube to provide a, violet blast of arc extinguish ing gas which passes outwardly from the adjacent end of the fuse tube, and to provide for the nor mal action of an expulsion fuse construction for the other portion of the fuse device, and in addi tion to the dual action hereinabove set forth, to provide for the quick mechanical withdrawal of any remaining portion of the fuse link from the fuse tube.

' Further objects are to provide a circuit inter rupter in which one end of the arc channel is: normally closed by a cap weakened along a pre'-' determined zone so that a portion of the cap is freely blown from the remainder of the device to provide free venting means, the portion so 14 Claims. (erect-120) Y blown from the device providing an aperture large enough to permit the passageItherethrough of the hereinbefore mentioned expellable plug.

Further objects are to provide a drop-out, high voltage, heavy duty'fuse construction in which a renewable or'refl'll unit is provided so that the major part of the apparatus may be used repeatedly,-the renewable unit being easily installed to replace a previously used unit.

Further objects are to provide a circuit interrupter in which a main arc is formed by the fusing of the fusible section of a fuse link, and in which an auxiliary arc is formed in spaced relation to the main are between two metal members" been extinguished.

Further objects are to provide a refill unit which is so constructed that it includes a'fuse' link as a unitary part thereof and which is so formed that it may be inserted in a fuse tube with'the same case as'an ordinary type of fuse link without requiringany more skill or care on the part of the lineman than that required for inserting the ordinary type of fuse link.

An embodiment of the invention is shown in the accompanying drawings, in which:' Figure 1 is a side elevation'showing'the circuit interrupter i'n operative position, a portion of the lower part of the apparatus being brokenaway and in section. Figure 2 ma view of the circuit interrupter removed from the stationary contacts, such view being partly in section and partly broken away.

' Figure Bis an'enlarged sectional view through the upper portion of the structure shown in Figf ure 2.

Figure 4 is a sectional view on the lined-4 of Figure 3. l I

Referring to the-drawings, it will be seen that the device'comprises an upper and a lower stationary terminal indicated generallyby the reference characters I and 2 which are supported re spectively by a pair of insulators 3 and lextend ingfrom a' base or main support 5 -nAfuse tube '6 is pivotally supported from the lowerte'rminalfi in a manner hereinafter described and is provided with an upper'terminal 1 having outwardly projecting members or pins 8 on'opposite sides thereof. The upper stationary terminal I may be constructed as set forth in detail in the patent to William O. Schultz, No}: 2,357,772 of September'B, 1944, for Cut-outconstruction, and may comprise a pair of spring arms 9 which are'pivotally' supported by a stationary member 10 and bear against oppositely disposed, downwardly slanting. cam portions l [which form aunitary "portion' 'of- 'the stationary member Ill;

The stationary member I l is provided with lower stops or outwardly projecting portions l2 to limit the downward motion of the spring arms 8." These spring arms are provided with downwardly depressed portions [3 and with outwardly slan ing guiding portions l4. Normally the projec-' tions 8 f the terminal 1 of the fuse tube are latched behind the downwardlydepressed' poi tions l3 of the spring arms A composite fuse link is located within the fuse tube Sand has aleader l5 projecting outwardly through the open lower end of the tube, the upper end of the tube being closed by means of a screw cap IS.

The lower portion of the fuse tube 8has ri idly clamped thereto alsleeve like member I! which is provided with a rearwardly and down-' w'ardly projecting arm l8pivoted as indicated at l 9 between a pair of arms formed integrally-with the main supporting lever 20; This main supporting lever 20 is provided with a pair of trunnions 2i removably supportedbythe-hook like portions'22 of the lower stationary terminal 2 and is provided with a rearwardly projecting portion 23 which normally engages the contactis'clamped between-thefuse link clamping lever 28 and the extension 21. 7

When the fuse-link is ruptured, as'will be described in greater detail hereinafter, the quick acting flip-out lever 25 extracts any'remaining' portion of the fuse link in aquick-ma-nner and rocks in a counterclockwise" direction under the influence of the'spring 29; The-fi'ip-out-lever 25 and the fuse link clamping lever 28- are so constructed that they have interengaging portions which coine into engagement when the flip-out lever has rocked a predetermined distance-so that thereafter the fuse linkclamping lever 28 and the flip-out lever 25 rock: as a unit and release the'leader ii of the-fuse link;

The particular construction of flip-out lever and fuse link clamping lever forms the subject matter of the copending application of William O. Schultz; Serial No. 465,560; filed November 14, 1942, now Patent No. 2,378,109, issued June 12; 1945, for Fuse constructions.

It is apparent that'when the fuse link is'ruptured, the main lever 28 is no longer held-in the position shown in Figure 1 and it rocks down wardly pivoting-about the -trunnions 2|. This moves the lower end-of the iuse-tubedownwardly and outwardly and allows-the projecting-portions B-cf the upperterminal 1 of the fuse'tube to disengage themselves from the latch spring arms 9, such spring arms, however, following the fuse tube downwardly for apredetermined distance-and being arrested in their downward motion by means of the projections I2 at the lower end of the cam portions Hoi the'upper' stationary terminal I. The fuse tubethereafter rocks outwardly and downwardly to'inoperative position.

The'fuse tube 8 may be of Bakelite or fiberor may be of Bakelite'lined withfiber in accord- 'evolve gas when acted upon by an arc.

ance with the usual practice. It is provided with a bore 30 extending therethrough which has an enlarged upperportion 3| adaptedtoreceive a refill unit formed as a unitary structure with the fuse link.

The refill unit comprises a fiber sleeve 32. An apertured. fiber plug 33 is screw threaded into and closes the lower end of the fiber sleeve 32. Atoms-shaped glass container 34 is supported from the plug 33. Preferably cushioning gaskets laare'positioned at each end of the container 34. This torus-shaped member contains a material, such as the liquid 36, which is adapted to Above the container 35 a metal sleeve like member 31 is positioned which has a central portion 38 provided with an aperture therethrough indicated at 39 and supported from the walls of the sleeve like member 31 by means of spider like arms 40. The lower end of the member 38 is provided with an annular, externally located oove.

The upper end of the fiber sleeve 32 carries a screw threaded fiber plug 4| which is provided with a relatively large aperture therethrough. Within this large aperture an expellable fiber plug 42 is provided. This expellable fiber plug has a smaller aperture therethrough. The plug 42 is in engagement with the plug 4| only adjacent its enlarged upper end so that it may be readily blown from the plug 4| in the event of heavy overloads in the manner hereinafter to appear to thereby provide a larger opening when very heavy overloads occur. The apparatus is so constructed that on moderate overloads the plug 42 is not blown from the plug 4|.

A metal sleeve 43 surrounds the upper part of the fiber sleeve 32 and has a portion 44 spun into an annular groove formed externally of the sleeve 32 to thus permanently lock the metal sleeve 43 to the fiber sleeve 32. The metal sleeve 43 is provided with a slightly larger upper portion 45 and with an outwardly extending annular flange 45 which rests upon the upper edge of the terminal 1 of the fuse tube. It is locked in place by means of the cap I6 hereinbefore mentioned. This cap is formed of Bakelite and is screwed on the terminal I and is provided with a weakened portion or zone in the form of an annular cut therearound as indicated by the reference character 41 so that the central portion of the cap is readily blown from the device when an overload occurs.

The flexible leader [5 is attached to a metal rod 48 which extends through the apertured plug 33 through the torus-shaped container 34 and into the lower portion of the metal sleeve 31. Its upper end carries a plurality of spring fingers 49 which releasably grip the lower end of the portion 38 of the metal sleeve or intermediate member and have rounded portions that fit within an annular roove formed in the lower end of such member 38 so as to have firm electrical contact therewith. The grip of the fingers 49 is not sufflcient to prevent the flip-out spring. pressed lever 25 from quickly withdrawing the leader l5 and the rod 48. However, the rod 48 is normally held against motion by means of a strain wire 50 whose lower end is attached to the rod 48 and whose upper end is attached to an upper contact cap 5!. This upper contact cap 5| is provided with a plurality of spring fingers 52 formed by cutting slots in the flanged portion of the cap 51. These spring fingersslidably and yieldably fit within the metal sleeve 43 and form good elecaladtaa trical contact therewith. It is to be noted that the metal cap rests upon the upper edge of the fiber sleeve 32 and it is to be noted further that both the metal cap 5| and the expellable plug 42 will freely pass through the cap l6 when the central portion thereof is blown off. The fuse link is provided with a fusible section 53 which has its upper end electrically connected to the cap 5| and its lower end electrically connected to the central metal member 38. The fuse link, therefore, includes the fusible section 53, the strain wire 50, the rod 48, and the flexible leader I5.

When an overload occurs, the fusible section 53 of the fuse link is ruptured and immediately thereafter the strain wire is ruptured. The quick acting fuse link extractor 25 or flip-out lever withdraws the rod or plunger 48 downwardly and an auxiliary arc is established extending from the lower end of the metal member 38 to the rod '48 and in series with the power or main are which extends upwardly from the upper end of the metal member 38. The auxiliary arc is quick- 1y elongated and drawn downwardly into proximity to the gas evolving material and breaks the container and acts on the gas evolving material and causes a violent blast of gas to pass upward- 1y through the expellable plug 42 and thus provides means for quickly extinguishing the power or main arc. If the overload is of moderate mag nitude, the expellable plug '42 remains in place but if the overload is very heavy, the expellable plug 42 is blown from the device and thus a larger vent opening is provided.

It is to be noted that on an overload of any value the weakened central portion of the cap I6 is blown off together with the metal cap 5|. It is to be noted particularly that the power are extends initially from the upper end of the metal member 38 to the metal cap 5| but almost instantly as the metal cap is blown outwardly passes over to the upper end of the metal sleeve 43. The auxiliary are is formed between the upper end of the plunger or rod 48 and the lower end of the metal member 38 and is in series with the power arc. This auxiliary arc is very quickly extended as explained hereinabove as the gap between the rod 48 and the lower end of the metal member 38 is quickly lengthened, thus preventing restriking after the extinguishing of the power are has taken place.

It is preferable to flare the open lower ends of both the plugs 42 and 4| to facilitate the flow of gas into the restricted aperture of the plug 42 or the less restricted aperture of the plug 4| in the event the plug 42 has been blown from the device as a result of a heavy overload.

It is to be noted further that in the event the circuit is not interrupted prior to the time the upper end of the rod 48. passes downwardly through the apertured fiber plug 33, the ordinary expulsion action takes places for the lower portion of the fuse tube 6 in addition to the ex-, tinguishing action due to the violent blast of gas hereinbefore described from the upper end of the fuse tube.

The material adapted to evolve gas when acted upon by the auxiliary arc and indicated by the reference character 36 may be any suitable liquid, such as carbon tetrachloride, methylene chloride or chloroform. If desired any other suitable material can be used. For example, solid material, such as compressed boric acid disks or powdered boric acid carried in a suitable container may be used. It is obvious also that if desired silicic acid, gunpowder, or any other suitable powdered 6, material could be used; a suitable container be ing provided for such material. After the circuit interrupter has functioned and the fuse tube has dropped to its lowermost or inoperative position, it may be removed by means of a switch stick in the usual mannerand after refusing may bereplaced by meansof a switch stick and rocked into position, a suitable eyeleted portion 54 being formed integrally with the upper terminal 1 and being adapted to be engaged by the switch stick after the trunnions 2| of the fuse tube have been placed in proper relation to the hook like supports 22 of the lower stationary terminal.

In refusing, a composite renewable unit and fuse link is substituted for the previous unit. The remainder of the cap |6is unscrewed from the fuse tube and the fiber sleeve 32 is bodily removed through the upper end of the fuse tube 6. Thereafter a new unit is inserted through the upper end of the fuse tube allowing the leader |5 to project downwardly and outwardly from the lower end of the fuse tube. Thereafter a new were is screwed into place and the leader l5 locked betweenv the fuse link clampin lever and the ex-'- tension 21 of the main lever 23 after the flip-out device has been rocked back into its initial position. p

It will be seen that the composite renewable unit and fuse link may be inserted in the fuse tube with the same facility as an ordinary type of fuse link and that no particular skill is required of the operator. Also it will be seen that the renewable units are relatively inexpensive and may be readily made. f

It will be seen that this invention provides a novel form of high voltage, heavy duty circuit interrupter in which provision is made for handling both heavy and light overloads or overloads of all intermediate values. Under a light overload a relatively restricted passage is provided for the blast of arc extinguishing gas, whereas for a relatively heavy overload the expellable plug is expelled and a larger passage is provided for the blast of arc extinguishing gas, thus guarding against the building'up of excessive internal pressure.

It will be seen further that a circuit interrupter has been provided in which a main arc is formed at a predetermined definite location and an auxiliary arc is formed in series with said main arc and is elongated while the main arc is being extinguishred due to the violent blast of are extinguishing gas. This elongation of the auxiliary are prevents restriking after the main arc has been extinguished. 1

Although thisinvention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

1. A circuit interrupter comprising a body portion provided with an arc channel, means adapted to interrupt a circuit under overload andform a mainarc in said are channel, gas liberating means adapted toliberate gas when acted upon by an arc, means for forming an auxiliary arc in proximity to said gas liberating means. said gas liberating means being normally out of con.- tact with the means for forming an auxiliary arc, and an expellable aperture-d plug through which said main arc is formed and through which the liberated gas passes to extinguish said main are, said plug being normally positioned in said are channel, said plug remaining in place in said arc 7 channel for moderate. overloads,to DlTQvide-ia restricted passage and being expelled on..hea vy overloads to provide a larger passage.

2. A circuit interrupter comprising a body portion provided with an arc channel, means adapted to interrupt a circuit under overload and form a main arc in said arc channel, gas liberating means located within said are channel and adapted to liberate gas when acted upon by an are, biased means for forming an, auxiliary arc in proximity to said gas liberating means and for extending said auxiliary, arc, said gas liberating means being normally out of contact with the means for formingan auxiliary arc, and an expellable apertured plug through which said main arc is formed and. through which the lib,- erated gas passes to extinguish said main. are, said plug being normally positioned in said are channel, said plug remaining in place in said arc channel for moderate overloads toprovide a restricted passage and being expelled on heavy over" loads to provide enlarger passage.

a 3. A circuit interrupter comprising a body portion, provided with an arc channel, a con ducting member within, said channel and spaced from one end of said channel, means adapted to interrupt a circuit under overload and form a main arc in said channel extendin from said conducting member to adjacent said end of said channel, gas liberating means spaced from said first, mentioned means and adapted to. liberate a gas when acted upon by an arc, means for forming an auxiliary arev in said channel extending from said conducting member into proximity to said gas liberatingmeans, and means ,for guiding the liberated gas into said main arc toextinguish said main arc.

4. A circuit. interrupt'er comprising a body portion provided with an arc channel, a conducting member within said channel and spaced from one end of said channel, means adapted to interrupt a circuit under overload and form a main arc. in said channel extending from said conducting member to' adjacent, said end of said channel, gas liberating means spaced from said first mentioned means and adapted to liberate gas when acted upon byanarc, means for forming an auxiliary arc in said. channel extending from said conductingmember. intoproximity to said gas, liberating means. and. for elongating said auxiliary arc, and means for guiding the liberated gas into said main arc to extinguish said main are.

5. A circuit interrupter comprising a body portion provided with an arc channel, a conducting member within said channel and, spaced from one end of said channel, means adapted to interrupt a circuit under overload and form a main arc in said channel, extending from said conducting member to adjacent said end of said channel, gas liberating means adapted to. liberate gas when acted upon by an arc, means normally electrically connected to said conducting member and biasedfor motion away from said conductingmember for forming an auxiliary arc in said channel extending from'said conducting member into proximity to said gas liberating means and independent of said main arc, and means for guiding the liberated gas into said main arc to extinguish said main arc. V

6. A circuit interrupter comprising a body portion provided with an arc channel, a conducting member within said channel and spaced from one end of. said channel, means adapted to interrupt a circuit under overload, and form a main arc in said, channel extending from said conducting memberto adjacent said end of said channel, gas liberating means adapted to libel;- ate gas when acted upon by an arc, a retractable plunger normally electrically connected to said conducting member and biased for motion away from said conducting member for forming an auxiliary arc in said channel extending from said conducting member into proximity to said gas liberating means and independent of said main arc, and means for guiding the liberated gas into said main arc to extinguish said main are.

7. A circuit interrupter comprising a body portion provided with an arc channel, an apertured conducting member within said are channel and spaced from one end of said channel, means adapted to interrupt a circuit under overload and form a main arc in said channel extending from said conducting member to adjacent said end of said channel and including a portion extending through the aperture in said conducting member and adapted to be severed on overload, gas liberating means adapted to liberate gas when acted upon by an are, a biased plunger normally electrically connected to said conducting member andinormally restrained by said severable portion for drawing an auxiliary are from said apertured conducting member into proximity to said gas liberating means, and means for guiding the liberated gas into said main arc to extinguish said main arc.

8. A circuit interrupter comprising a body portion providedwith an arc channel, an apertured conducting member within said are channel and spaced from one end of said channel, means adapted to interrupt a circuit under overload and form a main arc in said channel extending from said conducting member to adjacent said end of said channel and including a portion extending through the aperture in said conducting memberand adapted to be severed on overload, gas liberating means adapted to liberate gas when acted upon by an arc, a biased plunger normally electrically connected to said, conducting member and normally restrained by said severable portion for drawing an auxiliary are from said apertured conducting member into proximity to said gas liberating means and for elongating said auxiliary arc, and means for guiding the liberated gas into said main arc to extinguish said main arc,

; 9. A high voltage, heavy duty fuse construction comprising a body portion provided with an arc channel and having a terminal adjacent one end of said channel, an apertured conducting member withinsaid arc. channel and spaced from the said. end of said are channel, a fuse link including a fusible section electrically connecting one end of said conducting member and said terminal, gas liberating means adapted to liberate gas when acted upon by an are located adjacent the other end of said conducting member, a plunger normally electrically connected to the last mentioned end of said conducting member and biased for motion away from said conducting member to draw an auxiliary are from said conducting member into proximity to said .gas liberating means, a strain wire attached at one end to said plunger and normally restraining said plunger and extending through the aperture of said conducting member and attached at the other end at a point adjacent the said end of said channel and electrically connected with said terminal, andv means for directing the liberated gas into the area adjacent said fusible section when said fusible section and strain wire are ruptured on overload.

10. A fuse construction comprising a body por tion provided with an arc channel, means dividing said are channel into a first portion adjacent one end of said body portion and a second portion extending from the first portion of said are channel through to the other end of said body portion, a fuse link in said are channel having a fusible section located in the first portion of said are channel and upon rupture on overload adapted to form a main arc in said first portion of said are channel, said fuse link including a movable portion extending from the first portion through the second portion of said are channel, and gas liberating means located in said are channel and spaced axially from said fusible section and adapted to liberate gas when acted upon by an are, said movable portion of said fuse link being biased for motion outwardly from said are channel and adapted to form an auxiliary arc and draw said auxiliary are into proximity to said gas liberating means, means for guiding the liberated gas into said main arc, the second portion of said are channel having an expulsive-action with reference to the auxiliary arc in the event the main arc is not extinguished by the gas in the first portion of said are channel.

11. A refill unit'for a circuit interrupter having a body portion provided with an arc channel and having a terminal adjacent one end and retracting means adjacent the other end, said refill unit comprising a sleeve adapted to be inserted in the arc channel and having conducting means for electrical connection with said terminal and having a retractable portion adapted to be connected to the retracting means, an intermediate stationary conductor within said sleeve, a fusible section joining the said conducting means and one end of said stationary conductor, gas liberating means adapted to liberate gas when acted upon by an arc, mean for directing the liberated gas into the main are incident to rupture of the fusible section on overload, and means normally holding said retractable portion in electrical engagement with the other end of said stationary conductor and releasing said retractable portion on rupture of said fusible section, said retractable portion drawing an auxiliary are from said stationary conductor into proximity to said gas liberating means when said retractable portion is released.

12. A circuit interrupter comprising a body portion provided with an arc channel and having a terminal adjacent one end and having retracting means located externally of said arc channel adjacent the other end of said are channel; and a unit comprising a sleeve located within the arc channel, a stationary conductor located Within said sleeve, fusible means electrically connecting one end of said stationary conductor to said terminal, a retractable member normally in electrical connection with the other end of said stationary conductor and extending outwardly from said are channel and connected to said retracting means, ga liberating means located Within said sleeve and adapted 'to liberate gas when acted upon by an arc, and means normally holding said retractable member in electrical connection with said stationary conductor and releasing said retractable member following rupture of said fusible section, said retractable memher when released drawing an auxiliary arc from said stationary conductor into proximity to said gas liberating means.

13. A circuit interrupter comprising two main portions, one of said main portions being a body portion provided with an arc channel and having a terminal adjacent one end of said are channel and retracting means located externally of said are channel adjacent the other end of said are channel, the other of said portions comprising an insulating sleeve located within said are channel and having a terminal connected to the terminal of said body portion, an apertured plug carriedv within said sleeve adjacent one end of said sleeve,' a stationary conductor located within said sleeve intermediate the ends thereof, gas liberating material located within said sleeve adjacent the other end thereof, a retractable member connected to said retracting means and extendinginto the last mentioned end of said sleeve and being normally electrically connected to said stationary conductor adjacent one end thereof, a fusible section extending through said apertured plug and electrically connecting the other end of said stationary conductor to the terminal of said sleeve, and means normally holding said retractable member in lectrical connection with said stationary conductor and releasing said retractable member upon rupture of said fusible section on overload.

14. A circuit interrupter comprising two main portions, one of said main portions being a body portion provided with an arc channel and having a terminal adjacent one end of said are channel and retracting means located externally of said are channel adjacent the other end of said arc channel, the other of said portions comprising" an insulating sleeve located within said are channel and having a terminal connected to the terminal of said body portion, a pair of concentrically arranged apertured plugs located in said sleeve adjacent one end of said sleeve, the innermost of said apertured plugs being expellable under high gas pressure, a stationar conductor located Withinsaid sleeve intermediate the ends thereof, gas liberating material located within said sleeve adjacent the other end thereof, a retractable member connected to said retracting means and extending into the last mentioned end of said sleev and being normally electrically connected to said stationary conductor adjacent one end thereof, a fusible section extending through the innermost of said apertured plugs and electrically connecting the other end of said stationary conductor to the terminal of said sleeve, and means normally holding said retractable member in electrical connection with said stationary conductor and releasing said retractable member upon rupture of said fusible section on overload.

RALPH H. EARLE.

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

UNITED STATES PATENTS Number Name Date 2,091,430 Conrad Aug. 31, 1937 Re. 20,450 Hill July 20, 1937

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