US2191746A - Combustion chamber in cylinder heads of internal combustion engines - Google Patents

Description

Feb 27 1940 J. A. H. BARKEIJ GMBUSTION CHAMBER IN CYLINDER BEADS 0F INTERNAL COMBUSTIN` ENGINES Fiied uarcn 2, 193s 2 Sheets-Sheet 1 Patented F eb. 27, 1940 COMBUSTION CHAMBER IN CYLINDER HEADS OF INTERNAL COMBUBTION ENGINES Jean A. H Barkeij, Altadena, Calif.

*Application March 2,

14 Claims.

The present invention is related to the subject matter of my previous 'application No. 325,115 of December 10, 1928, now Patent No. 2,050,688, of August 11, 1936, and also related to the subject matter of myapplication No. 291,599 of July l0,

1928, and is a continuation in part of my application No. '721,721 of April 20, 1934.

This invention relates to the combustion chamber of a valve-in-head engine particularly. My object is to construct a restricted passage between the cylinder bore (or piston chamber) and the combustion chamber containing the spark .ignition means, and to place in such a construction the spark ignition means closer to the edge of the'exhaustvalve than to the edge oi' the inlet valve. Said latter construction appears entirely satisfactory at any speed, because the turbulence created by said throat (mechanical turbulence) prevents misflring at any speed and especially at low speeds. Said mechanical turbulence prevents eifectively stagnation of gases in the neighborhood of the spark ignition means.

Therefore,although the presentvinvention is particularly shown in relation with a cylinder head having the valves in the head (the valve-in-head type), it stands to reason that said principles may be applied on any type of four-stroke cycle engine having exhaust and inlet valves or one exhaust valve and one inlet valve in a main explosion chamber communicating with said piston chamber orl cylinder bore through said restricted passage between bore and the combustlon chamber, containing both of saidvalves.

I further place the spark ignition means in an auxiliary combustion chamber, having either a non-restricted passage or a restricted passage with the main combustion chamber.

My rst object is to construct both valves, the

inlet and .exhaust valve inverted in the headY of the engine, and to locate both valves substantially above the cylinder bore, so that the major part of saidl valves, are located above the cylinder bore when looking'at said valves in top view towards said cylinder bore.

They both communicate either with the cylinder bore or piston chamber directly without any intermediate restricted passage i as shown in Figs. 1 and 1A), or communicate with the piston chamber through an intermediate restricted passage therebetween.

This restricted passage is shown in Figs. 4 and 5, and may be formed as preferrrd provided it causes a mechanical turbulence of the charge in the main combustion chamber and in the auxiliary chamber at the end of the compression 1938, Serial No. 198,550

period (and apart. of course, from the restricted passage which may be constructed between the said main chamber and auxiliary chamber), ac- `celerating thereby the burningA of the charge and insuring tiring thereof by the spark plug wheresoever yit may be placed in such a -com bustion chamber. l As shown in Fig. 4 the undersurface of the cylinder head may form the entire restricted passage, but the area of this restricted passage should be liberal and substantially greater than the area or inlet capacity of the inlet valve above it, so that the fresh gases are not obstructed when streaming from the inlet valve towards the piston chamber I andpast this restricted passage. It is, however, understood that this restricted passage between the main combustion chamber and the piston chamber. may be formed either entirely by the cylinder head, or partly by the cylinder head and partly bythe cylinder bore. It may lie further entirely over the cylinder bore or at one side thereof.

My second object is to construct the main combustion chamber directly below the valves, and to construct adjacent thereto a second, smaller, explosion chamber or bay adjacent to the main explosion chamber, these two chambers being separated by a passage, which may or may not be restricted. In my Patent No. 2,050,688 0i' Au#- gust 11, 1936, has been claimed the variety shown in Figs. 1 to 5 showing a combustion chamber, or chambers, without valves, the valves being placed outside said chambers or chamber.

The volume of said additional chamber should not be greater than about a quarter of the main chamber but can be made much smaller of course. This auxiliary chamber' may have any shape, but the gases ignited in said chamber must ignite first the gas mass in the neighborhood of the exhaust valve.

My third lobject is to provide the larger combustion chamber with a spark plug in substantially horizontal position, and likewise the spark plug in the smaller explosion chamber.

My fourth object is to place both. of said spark plugs approximately in a plane perpendicular to the piston pin, said plane passing through the axis of the exhaust valve approximately.

My fth object is to have simultaneous ignition from both spark plugs, if they are -both applied on this combustion chamber. In other words a single spark plug may be used and mounted in either one of said chambers, in whichlatter case these form practically one chamber.

My sixth object is to raise the compression ratio'inV said engine by the location of said single or double spark plugs in certain positions closer to the exhaust valve than to the inlet valve for reasons to be explained hereinafter.

These various objects are shown in various combinations in the following drawings, but they all contain the feature of the first and sixth object.

Referring to the drawings, Fig. 1 is a vertical section of a cylinder and cylinder head on the section lines I-I of Fig. 1A, and show the application of two spark plugs firing simultaneously.

Fig. 1A is a horizontal section of the cylinder head on the section line iA-IA of Fig. 1. Figs. 2 to 5 are similar vertical sections showing only a single spark plug.

The cylinder is, of course, only one of a multicylinder-engine. In said figures the numeral l designates the cylinder head, 2 the cylinder, and la, 2a are respectively the water jackets thereof. Numeral l designates the piston, I the piston pin, l the connecting rod. 8 is the main explosion chamber having the greater volume, 'I the smaller chamber. Numeral i designates the spark plug in'the smaller chamber, 8 that in the larger chamber. Numeral I designates the exhaust valve, Illa the exhaust passage, il is the inlet valve, Ila the inlet passage. However if a single chamber is shown, either spark plug may be designated by the numeral 8 or 9.

The combustion chamber 6 is shown here as communicating unrestrictedly with the piston chamber 3a, but there may be such a restriction if a mechanical turbulence is desired to be caused in the main chamber i, by the piston approaching said restriction when reaching its top dead center position. The type with the restricted passage is shown in Figs. 4 and 5 on the second sheet.

'I'his restricted passage should be carefully discernedA from another restricted passage la which may be formed between the main combustion chamber 6 and the additional combustion chamber l. In Fig. 1 there is no such restriction, because the circular form of the main combustion chamber 6 goes over into the angular chamber 'l without forming any restriction at all so that they form virtually one chamber. .This form of Fig. l is very distinct from the type shown in Fig. 5 in which the vchamber l is positively separatedfrom the main chamber 6 by a restricted passage, which has to perform a double and definite function separate from the 'other features to be discussed hereinafter at the end of the specification.

In the present construction the valves can open and close at any desired time, since the distance between valves and top of piston when on top dead center position is sufficient to allow any liberal lift of said valves downwardly. This feature is retained in all types and modifications, and is closely connected with the feature to retain the capacity of both valves to inhale and exhalerespectively fresh and burned gases.

Another feature of extreme importance is the position of the spark plug. Spark plug 8 is offset in chamber 1 and so is,spark plug 9 in chamber 6 from a transverse plane midway the axes of said valves. If only a main chamber 6 is used containing both valves, the spark plug 9 being located in the neighborhood of the exhaust valve, the gas in this neighborhood begins to burn first and compresses the unburned portion of the gas towards the cooler regions of said chamber. The exhaust valve is by far the hottest part in the explosion chamber and the heat radiating there- ,of the cylinder.

from causes detonation of the unburned portion of the gas when the ignition flame is initiated in the neighborhood of the inlet valve, or at a pointremote from the exhaust valve in said chamber.

Equally when spark plug 8 alone is used and when placed as shown in Fig. 1A, the gas in the neighborhood of the exhaust valve is burned first and during a certain stadium of the combustion a portion of the gas is crowded towards the cooler regions of the combustion chamber.

When both spark plugs are fired simultaneously at least one of them should be placed as shown in Fig. 1A, but preferably both of them, as shown.

, In the latter case, the action of the ignition flame from chamber l is somewhat undone, as the flame therefrom will compress not only an unburned portion of gas in chamberj but also a burned or burning portion of gas ignited by spark plug 9. Both plugs will do the same thing, crowd the unburned portion towards valve Il, and always away from the exhaust valve.

Therefore the latter construction with two spark plugs is only preferred for very fast motors and where fuel economy is of first importance, like in truck engines, and in aeroplane engines.

I do not intend therefore to restrict myself to the construction of both plugs ilring simultaneously, but consider the scope of this application to lie about in the scope of the following claims, including the use of a single spark plug in certain positiions.

'Ihe position of the spark plug 9 or that of 8, or both, is therefore dependent on the position of the exhaust valve, but the position of this exhaust valve may be anywhere, except in the center of the combustion chamber, opening downwardly as shown. The form of the combustion chamber changing according to the relative position of the valves is therefore also secondary, as the form thereof depends largely upon the relative position of the valves that is in upright or downward position. The feature of the double chamber is therefore also unimportant for so far as concerns theposition of the spark plug near the exhaust valve, and in the same plane therewith a single chamber may be used if only spark plug 9 is used, or if only spark plug 8 is used, diametrically opposite the position of spark plug 9. Even if both spark plugs are fired simultaneously, they may be placed in a single chamber. with 0r Without the restricted passage, but both of them are by preference substantially in the same transverse plane with the axis of the exhaust valve, if the valves in the engine are placed in a single plane lengthwise the engine.

The mechanism to lift the valves is not shown in the drawings, but these usual pushrods are supposed to be either to the right or to the left If the pushrods are on one side, the exhaust and inlet manifold are usually at the other side.

It is finally preferred to construct the sepmethod of igniting a fuel-air mixture in an internal combustion engine of the explosive type. rifhe chamber may have practically any form, it may be a double or a single chamber with or without a restricted passage therebetween. The

location of the single or double spark plugs alheat from the yexhaust valve into said mixture,

especially in the neighborhood of the -exhaust valve and especially of its very center this being Vthe hottest part in the combustion chamber.

Assuming that these temperatures remain the same with any position of the spark plug(s). it remains a fact that during the ignition, the exhaust valve continues to radiate heat. When the pressure rises due to a part of the fresh gases already burned after an initial ignition by the spark plug near the exhaust valve, and when the unburned part is crowded by the burned part towards the inlet valve, the inlet valve will not radiate heat into said unburned part and therefore will not cause detonation in said unburned part because the heat of the inlet valve will not be sufficient to cause detonation thereof.

Conversely if the unburned part (raised in temperature by the pressure of the burned part initially ignited near the inlet valve) is crowded towards the exhaust valve, the radiation of heat by said exhaust valve into the said unburned part will cause detonation in said unburned part even when the temperature and pressure of said gases in the neighborhood of the exhaust valve were the same as those near the inlet valve. During the entire compression period. however, the gases in theneighborhood o f the exhaust valve are inuenced by the heat of the exhaust valve, notwithstanding the fact that the fresh charge remains more or less in a state of turbulence, especially if a restricted passage is applied between combustion chamber and piston chamber (a socalled Ricardo head, here for valve-inf-head structures.) 1

If detonation begins to occurin the neighborhood of the exhaust valve (the gas being ignited near the inlet valvel, a vicious circle starts, as the exhaust valve gets hotter and hotter by said detonation, and this causes heat losses and a decrease in thermal efficiency. When igniting the charge initially in the neighborhood of the exhaust valve, this vicious circle cannot start, heat losses are less. thermal eiciency higher. Therefore the position of the spark plug is of profound importance and significance.

As has been stated hereinbefore that the valves maybe placed anywhere and the form of the combustion chamber may be valmost any shape, has only one restriction. The exhaust valve should not be placed in the center of the combustion chamber, because if the single spark plug is placed close to it, the ame will propagate in all directions towards all corners of the chamber and it would not be possible to crowd the unburnt portion of the gas, compressed by the pressure of the burnt portion of the gas before detonation may occur, towards the cooler portion of the chamber where the other valve is located. If the exhaust valve is placed more or less lin a corner and the ignition is started there, it stands to reason that all of the gas in the neighborhood oi the exhaust valve can be burned rst and the pressure created thereby can crowd the unburned portion away from the exhaust valve' region and towards the remaining part of this chamber containing the inlet valve. It furtherv stands toreason that it is totally unimportant where or whether the inlet valve is placed in the main chamber or not, provided the single spark plug is placed closer to the exhaust valve than to the inlet valve. The gas must be initially ignited in the neighborhood of the exhaust valve and preferably in an auxiliary chamber in such a way that the flame darting from the spark plug in said auxiliary chamber reaches first the neighborhood of the exhaust valve and burns ilrst the charge adjacent to thel exhaust valve.

It is further' an important feature that the inlet and exhaust valve or valves are so located that the reciprocating piston never can touch them. This is an important feature in any type of internal combustion engine, the high compression type especially, because if the compression space is very small the'valves can move entirely -free from the piston and never can be touched by them, even if they did not close in time.

In Figs. 2 to 5 I have shown the two types discussed, the one with a restricted passage between the combustion chamber 8 and the piston chamber. 3a,- and the other without such a restricted passage, but all using only a single sparkplug closer to the edge or centerof the exhaust valve than to the edge or center of the inlet valve. The position in horizontal cross section of the sparkplugs in Figs. 2 and 5 are similar to the kcorresponding positions of sparkplugs 8 and 9 in F18. 1A.

Fig. 2 shows the said second type and the sparkplug 8 as shown in Fig. 1A.

Fig. 3 shows the same type, showing the sparkplug 8 as shown in Fig'. 1A.

Fig. l having substantially no restricted passage between the main chamber 6 and the additional chamber 1, and the type shown inFig. 5 in which there is such Va. substantial restriction between these two chambers.

On the compression stroke in the type of Fig. 5, the mixture is forced into the chamber 1, through the restricted passage la, with greater speed and causing therein a greater turbulence before the spark ignites the mixture therein, than in the type of Fig. l or Fig. 3. Therefore we may expect in the first type, also on account of such a kind of Venturi passage, that the burned gases will stream from said chamber 1 into the chamber 6 with greater speed than in the case of Fig. 1.

I may employ either one of said constructions in either one o f the combustion .chambers discussed, the one having a restricted passage between the cylinder bore and the combustion' gases streaming therefrom upon ignition reach the neighborhood of the exhaust valve rst.

I may construct such passages la', and chambers 1, in varying form, increasing or decreasing the area of said passage relative to the volume of the additional chamber 1, and I may vary the volume of the chamber 'I relative to the volume of chamber 6. By narrowing such a passage I increase the speed with which the fresh mixture enters this chamber 1 and likewise I increase 'the speed with which the burned gases stream therefrom into chamber i, to suit different engines and different conditions.

Various modifications are obvious and fall under the scope of the following claims.`

I claim:

1. In a four stroke cycle internal combustion engine of the explosive type, a cylinder with a cylinder bore, a cylinder head1, an explosion chamber in said cylinder head communicating with said cylinder bore, an inlet valve and an exhaust valve-in said explosionchamber, an

additional explosion chamber of relatively smallvolume compared with said main explosion chamber and communicating restrictedly with said main explosion chamber, a sparkplug in said additional chamber at the periphery of said combustion chamber and located closer to the edge of the exhaust valve than to the edge o1' said inlet valve, said additional explosion chamber being otherwise permanently closed, said inlet valve admitting all the gas to be burned to said main combustion chamber, and another sparkplug substantially diametrically opposite said first sparkplug across the cylinder bore and means to ignite said sparkplugs substantially simultaneously.

2. The combination of claim 1, in which said sparkplug and additional chamber are so located that the burned gases streaming from said latter chamber reach the edge of said exhaust valve before reaching the edge of said inlet valve in said, main explosion chamber.

3. In a four stroke cycle internal combustion engine of the explosive type, a cylinder with a cylinder bore, a cylinder head, a main explosion chamber in said cylinder head communicating restrictedly with said cylinder bore, an inlet and an exhaust valve in said main chamber, an additional explosion chamber of relatively small volume compared with said main chamber, cornmunicating with said main chamber through a passage, said latter chamber being otherwise permanently closed, a sparkplug in said additional explosion chamber located substantially closer to the edge of said exhaust valve than to the edge of said inlet valve in said main chamber, said inlet valve admitting all the gas to be burned to said main combustion chamber, and another sparkplug on the other side of said cylinder bore similarly situated and means to fire said sparkplugs substantially simultaneously.

4. The combination of claim 3, in which a. second sparkplug is placed in said main chamber also located substantially closer to the edge of said exhaust valve than to the edge of said inlet valve in said main chamber.

5. In a four stroke internal combustion engine of the explosive type, a cylinder with a cylinder bore, a piston therein, a cylinder head closing said. bore, a main combustion chamber in said head communicating with said cylinder bore through a restricted passage therebetween, an exhaust valve and an inlet valve in said chamber opening substantially downwardly into said chamber towards said piston, two sparkplugs in said chamber both located substantially further ber than from the center of said exhaust valve and both substantially farther away from the edge of inlet valve than from the edge of said. exhaust valve and the center of said exhaust valve being substantially removed from the center of said combustion chamber and said sparkplug being removed substantially from the center of said combustion chamber.

6. The combination of claim 5, in which one of said sparkplugs is placed further in an odset, additional chamber, communicating with said main chamber restrictedly.

7. In an internal combustion engine of the four-stroke cycle valve-in-head type, a cylinder, a piston reciprocating therein, a cylinder head having a main combustion chamber communicating restrictedly with the piston chamber in said cylinder through a restricted passage overlying the cylinder bore at one side thereof, inverted intake and exhaust valves opening downwardly in said chamber, asingle sparkplug in said combustion chamber located substantially closer to the center of said exhaust valve than to the center of said combustion chamber, and located at the same time in an ignition bay located at the periphery of said main combustion chamber.

8. In an internal combustion engine of the four-stroke cycle valve-in-head type, a cylinder, a piston reciprocating therein, a cylinder head having a main combustion chamber communieating restrictedly with the piston chamber in said cylinder, an intake valve and an exhaust valve in said cylinder head opening downwardly into said combustion chamber toward said piston, and the restricted communication having a passage substantially greater than the area of said inlet valve, an additional explosion chamber of relatively small volume compared with said main chamber, having a single sparkplug in said additional chamber, and located closer to the center of said exhaust valve than to the center of said combustion chamber, and located further closer to the center of said exhaust valve than to the center of said inlet valve, said additional chamber located at the outer edge of said main combustion chamber.

9. In a four-stroke cycle internal combustion engine of the valve-in-head type, a cylinder with a cylinder bore, a cylinder head closing said bore, a main explosion chamber in said head communieating restrictedly with said cylinder bore, an exhaust valve and an inlet valve in said main chamber in inverted position opening downwardly into said chamber, said restricted communication having an area exceeding the inlet area of said inlet valve, an ignition bay communicating restrictedly with said main chamber and a single sparkplug located at the inside edge of said ignition bay and at the same time closer to the edge of said exhaust valve than to the edge of said inlet valve. l

10. In afour-stroke cycle internal combustion engine of the explosive type, a cylinder with a cylinder bore, a piston therein, a cylinder head closing said bore, a main combustion chamber in said head communicating with said cylinder bore through a restricted passage therebetween which overlies the cylinder bore at one side thereof, an exhaust valve and an inlet valve in said chamber opening substantially downwardly into said chamber towards said piston, a single sparkplug in a small auxiliary chamber communicating with said main chamber, the exit of saidauxlliary chamber located substantially further away from the center of said explosion chamber than from the center of said exhaust valve and the center of said exhaust valve being substantially removed from the center of said combustion chamber.

il. The combination of claim 10 in which said auxiliary chamber communicates unrestrictedly with said main chamber.

12. The combination oi claim 10 in which said auxiliary chamber or ignition bay communicates substantially restrictedly with said main chamber.

13. In a four-stroke cycle internal combustion engine of the explosive type and of the valve-inhead type, a cylinder with a cylinder bore, a cylinder head closing said bore, a main explosion chamber in said head communicating restrictedly with said cylinder bore, an exhaust valve and an inlet .valve in inverted position in said main chamber, an ignition bay located at one side of said main chamber and having a volume substantially smaller than that oi said main chamber, not exceeding 25 percent thereof, said ignition bay having an exit located substantially on that side of said main chamber where said exhaust valve is located, a single sparkplug in said ignition bay so that the ame starting therefrom upon ignition does not hit directly the exhaust valve but bums ilrst the mixture in the neighborhood of said exhaust valve and subsequently that in the neighborhood ot said inlet valve. said ignition bay communicating restrictedly with said main chamber and said single sparkplug being combustion chamber in said head communicating restrictedly with said cylinder bore, valve controlled exhaust and inlet ports communicating with said main combustion chamber, an auxillary combustion chamber communicating restrictedly with said main chamber above said restricted passage, and having a volume'substantially smaller than that of said main chamber and. not exceeding one third of the total volume of the compression space thereof. and afsingl'e sparkplug in said auxiliary chamber ,and another sparkplug in said main chamber.

J. A. H. BARKEIJ.

DISCLAIMER 2,191,746.Jean- A. H.' Barkej, Altadena, Calif. CouBUsnoN CHAMBER 1N CYLIN- DER HEADS or INTERNAL CoMBUszrloN ENGINES. Patent dated Feb. 27, 1940. Disclaimer filed Nov. 15, 1946, by the inventor. Hereby enters disclaimer -to claim 4 and to the subject matter contained in lines 44 to 53 inclusive, second column, page I.

[Qc'ial Gazette December 10, 1946.]

Certificate of Correction Patent No. 2,191,746.

February 27, 1940.

. a JEAN A. H. BARKEIJ A It is hereby certied that error ap ears in the above numbered patent requiring correction as follows: In' the dra Fig. 5 should appear as shown below instead oi as in the patent? griffig/r f FIG. 5 and that the said Letters Patent should be read with this correction there same may conform tothe record of the case in the Patent Olice.

in that the Signed and sealed this 4th day of March, A. D. 1947.

LESLIE FRAZER,

First Assistant Uommz'ssoner of Patents.

DISCLAIMER 2,191,746.-Jean A. H. Barkeij, Altadena, Calif. CoMBUs'rioN CHAMBERS 1N CYLINDER 'HEADS or INTERNAL CoMBUs'rIoN ENGINES. Patent dated Feb. 27, 1940. Disclaimer filed Mar. 24, 1947, by thc inventor.

Hereb enters disclaimer whereby the scope of the disclaimed fourth, and fifth object, an claim 4, is emphatically applied, i. c. eliminated from the entire patent or specification, drawings, description and claims.

Therefore the fifth ob'eet, i. e. simultaneous firing has been already eliminated by the first disclaimer of ov. 15, 1946, from the explanatory or descriptive matter in lines 27 to 32 on page 2, column 2, and from the lines 50 to 56 in the same column, and therefore also from the claims.

Therefore the fourth object, i. c. two sparkplugs closer to the edge of thc exhaust valve than to the edge of the inlet valve, has been already disclaimed by the first disclaimer of Nov. 15, 1946, from the scope of the-claims with two sparkplugs.

The condenser in Fig. 1a is disclaimed.

[Oficial Gazette May 20, 1.947.]

Disclaimer 2,191,746.Jean A. H. Barkeij, Altadena, Calif. ConBUs'rxoN Cullmann IN CYLIN- DEB HEADS or INTERNAL CouBUs'rxoN ENGINES. Patent dated Feb. 27, 1940. Disclaimer led Feb." 26, 1948, by the inventor.

Hereby enters disclaimer to pgs 2, column l, -9 inthe larger chamber, lines 24-25, page 2, column 1, 1n es 66-67, to -in chamber 6-, in line 4 same column to various objects are shown in various, and to -but they^al1 in lines 5-6 same column. l Y

Hereby limits the scopeof claims 1, 2, 3 to non-simultaneous firing in view of the prior disclaimers and in view of description in lines 28 to 33, page 2, column 2, and further limits the interval of non-simultaneous firing to the range of 2 to 12 cllgankshgft rotation, and preferably to the approximate center thereof which is a out 6 y And further limits the scope of claim 1 for so far as concerns the position of the second sparkplug, to a position closer to the edge of the inlet valve than to the edge of the exhaust valve on account'of the diametncally opposite osition of the second sllarkplug with respect to the first sparkplug, which is closerto t e edge of the exhaust v ve.

And further limits the scope of claim 3 for so far as concerns the second sparkplug to a osition closer to the ed e of the inlet valve than to the edge of the exhaust valve, and imits the Wordssimarly situated-solely to a position yin another auxiliary chamber communicating with the main chamber as shown in Fig. 1a, and not to a position also closer to the edge of the exhaust valve thaxl'to the edge of the inlet valve, as was claimed and subsequently disclaimed in claim 4, which limited claim 3 to such a osition only and originally.

And urther limits the sequence of the non-simultaneous to the sequence described in the description, in which the ignition isfinitiated in t e hottest part of the chamber, where the exhaust valve is located.

(Oficial Game April 2Q, 194s.)

Certificate of Correction February 27, 1940.

Patent No. 2,191,746.

JEAN A. `H. BARKEIJ It is hereby certified that error appears in the above numbered patent requiring correction as follows: In the drawing, Sheet 2, Figure 4 should appear as shown vbelow instead of as 1n the patentrs Patent should be read with this correction therein that the and that the said Lette same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 29th day of June, A. D. 1948;

THOMAS F. MURPHY,

Assistmtt Oommzssoner of Patents.

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