US2966149A

US2966149A - Compound engine system

Info

Publication number: US2966149A
Application number: US766527A
Authority: US
Inventors: Paul M Morse
Original assignee: THOMAS M MORSE
Current assignee: THOMAS M MORSE
Priority date: 1958-10-10
Filing date: 1958-10-10
Publication date: 1960-12-27
Anticipated expiration: 1977-12-27

Description

Dec- 27 1960 P. M. MORSE coMPoUND ENGINE SYSTEM 4 Sheets-Sheet 1 Filed Oct. l0, 1958 R. m. s mm 0 1 M M. www Il u m @w Y B v um QQ mm mm mw N\.\ v/NNN \N\ www NM/ Y mm l, vw n m 1L I 9@ uw i QN I i mm wm Qn QS uw mm S mw M n Dec. 27, 1960 P. M. MORSE COMPOUND ENGINE SYSTEM Filed Oct. 10, 1958 4 Sheets-Sheet 2 Paul M. Morse 1N VEN TOR.

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Dec. 27, 1960 P. M. MORSE coMPoUND ENGINE SYSTEM 4 Sheets-Sheet 5 Filed 0G12. 10, 1958 Pau! M. fam/"5@ 1N VEN TOR.

DCC 27, 1960 P. M. MORSE 2,966,149

COMPOUND ENGINE SYSTEM Filed 001'.. lO, 1958 A. Sheets-Sheet 4 Paw' M Mars@ INVENTOR.

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United States Patent fice 2,966,149 Paiemed Dee. 27, 196e COB/ROUND ENGINE SYSTEM Paul M. Morse, R.F.D. 1, Carlinviile, lll., assigner of fifty percent to Thomas M. Morse, Carlinville, Ill.

Filed Oct. 10, 1958, Ser. No. 7 66,527

7 Claims. (Cl. 12S-S1) This invention comprises a novel compound engine system and more particularly relates to an internal combustion engine wherein a multiple piston system operating in a single cylinder imparts reverse rotations to two interconnected parallel crankshafts.

The primary purpose of this invention is to provide an internal combustion engine wherein a multiple piston system imparts simultaneous rotation and power to a pair of contra-rotating crankshafts and for effecting a dynamic balance of the thrust, inertia effects and vibration of the reciprocating pistons and of the crankshafts.

A further object of the invention is to provide an internal combustion engine in accordance with the preceding object wherein a more effective development of the power derived from a reciprocating piston engine may be obtained and whereby the number of power impulses obtained from the piston assembly within a single cylinder during a single rotation of the crankshaft may be increased.

A further important object of the invention is to provide an internal combustion engine wherein there is obtained a reduction in the weight of the engine per horsepower, a greater durability and reliability of the engine is secured and wherein a simplified construction, lower initial cost and upkeep is realized.

Still another object of the invention is to provide an engine in accordance with the preceding objects which shall utilize a less expensive and a safer fuel.

Yet another important object of the invention is to provide an engine or combustion engine which will eliminate the usual electrical ignition system and the detrimental side eifects of the latter such as interference with radio and television transmission and reception.

Still another object of the invention is to provide an internal combustion engine in accordance with the preceding objects which will provide a more effective and compact exhaust and muiiier system and one which will be highly efficient in operation.

A more specific object of the invention is to provide an internal combustion engine having a plurality of pistons in a single cylinder and wherein the piston inertia at the reversal of motion of the same is utilized to cushion the reversal of the pistons and to convert kinetic energy of the same for compression of the working fluid in the combustion chambers of the engine.

Yet another object of the invention is to provide an internal combustion engine as set forth hereinbefore which shall be especially adapted for operating a pair of oppositely rotating propellers thus being especially useful for aircraft by eliminating or minimizing gyroscopic effects, torque reactions and the like.

A still further object of the invention is to provide in an engine of the character above set forth an effective pressure lubrication of the interior of the pistons and their rubbing surfaces.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure l is a front elevational view showing a portion of an aircraft provided with a pair of contra-rotating propellers for which the propulsive power plant of this invention is particularly adapted;

Figure 2 is a view in horizontal longitudinal section through the central portion of the engine in accordance with this invention, and showing the transmission and piston arrangement for the same, with the exhaust manifold and muer being shown in elevation and a part hereof being broken away;

Figure 3 is a Vertical longitudinal sectional view through the working cylinder of the engine of Figure 2, being taken substantially upon the plane indicated by the ection line 3 3 of Figure 2, certain concealed parts being shown in dotted lines therein and certain parts being broken away and omitted therefrom;

Figure 4 is a vertical transverse sectional view taken substantially upon the plane indicated by the section line 4 4 of Figure 2 and showing in particular one of the lubricating pumps and its driving means and also the means for actuating the fuel injectors of the engine;

Figure 5 is a vertical transverse sectional view taken substantially upon the plane indicated by the section line 5-5 of Figure 2 and showing in particular the exhaust discharge system of one of the combustion chambers of the engine;

Figure 6 is a vertical transverse se'ctional view taken substantially upon the plane indicated by the section line 6-6 of Figure 2 and showing in particular the compressed air charging system of the engine;

Figure 7 is a view similar to Figure 3 but showing the pistons therein in elevation and showing the positions of the pistons and crankshafts at the innermost stroke of the latter; and

Figure 8 is a view similar to Figure 7 but showing the position of the pistons at the outermost stroke of the crankshafts.

Figure l shows by way of example a particular environment or use for which the propulsive plant of this invention is especially designed. As shown in this iigure any suitable form of aircraft designated by the numeral 16 is provided with a pair of

propellers

12 and 14 which lrotate in opposite directions indicated by the arrows in this figure. The power plant of this invention includes a pair of oppositely rotating crankshafts, each of which is directly connected to one of the

propellers

12 and 14 for thereby operating the latter in opposite directions.

As shown more particularly in Figures 2 and 3, the power plant of this invention may comprise a single cylinder receiving therein multiple pistons for delivering power to a pair of crankshafts. It will be understood, however, that the principles of the invention comprehend a construction having a plurality of cylinders which may be disposed in parallel arrangement between and operatively connected to the pair of parallel crankshafts.

In the embodiment illustrated there is provided a single elongated cylinder 20 which at its two open opposite ends is provided with mounting flanges 22, each of which is secured as by a fastening bolt 24 to the corresponding mounting ange 26 of the

crankcases

28 and 30. Each of these crank cases is provided with suitable bearings 32 therein by means of which is journaled one end portion of a crankshaft 34 for the

casing

28 and 36 for the crankcase 3i). These crankshafts have connected thereto conven# tional connecting

rods

38 and 40 which extend into the opposite ends of the cylinder 20.

The

crankcases

28 and 30 as shown in Figure 2 project outwardly beyond the ends of the cylinder and include

housings

42 and 44 through which extend the

crankshaft

34 and 36, and in which the crankshafts are further journalled as at 46 and 48. In these two housings the crankshafts are provided with gears each designated by the numeral 50and which are engaged by gears 52 provided on the opposite extremities of a shaft 54 which comprises a means connecting the two crankshafts for reverse rotation.

As will be observed from Figures 2, 3, 7 and 8, the cylinder is provided with a plurality of air cooling ns as at 56', while the crankcases and their

housings

42 and 44 are provided with a plurality of similar tins as at 58. It will be understood, however, that other suitable cooling means other than air cooling can be provided for this engine in accordance with conventional practice.

With continuing reference to Figures 2 and 3 it will be observed that the two connecting rods 38 and 4@ are pivotally secured as by pins 60 and 62 to the opposite ends of Va pair of

concentric telescoping tubes

64 and 66 respectively. It will be observed that the inner tube 64 is open at both of its ends and along its length is provided with a series of radial ports 68 for a purpose to be subsequently apparent. The outer tube 66 is likewise open at both of its ends so that the pair of concentric tubes freely communicate with the two cranl-:cases through the open ends of the attached cylinder. The outer tube and its mid-portion is provided with a pair of longitudinally extending diametrically disposed slots 70 and the inner tube at its inward end carries a transversely extending cross pin 72 which extends through the slot 70 to the exterior thereof for a purpose to be subsequently apparent. As so far described it will thus be apparent that with the two crankshafts having their throws disposed 180 apart, that the connecting rods and the tubes attached thereto will be caused to reciprocate towards and from each other with a telescoping motion.

A multiple piston system is slidably received within the cylinder 20 and is disposed in the annular space between the pair of concentric tubes and the wall of the cylinder. The piston assembly includes a pair of

pistons

80 and 82 which are screw-threadedly engaged upon the opposite ends of the outer tube 66 and are thus held in fixed relation with respect to each other and are reciprocated with the outer tube by the connecting rod 40 upon operation of the crankshaft 36. As will be readily understood in accordance' with conventional practice, suitable piston rings 84 are provided for these two pistons upon their periphery to establish a huid-tight seal with the wall of the cylinder 20 in which the pistons reciprocate.

There is also provided an intermediate piston 36 which is xedly secured at its mid-portion to the previously mentioned pin 72 and thus reciprocates in the annular compartment lying between the concentric tubes and the surrounding cylinder, in response to reciprocation of the inner tube 64 by the connecting rod 3S and the crankshaft 34.

The intermediate piston is double-headed and provided` with a

piston head

88 and 99 at the opposite ends thereof and which heads are opposed to the cylinders 8E) and 82 previously mentioned. Suitable external and internal piston rings 92 and 94 respectively are carried by eachV piston, while that at 98 is disposed between the outer piston 82` andV the adjacent piston head 9e of the intermediate cylinder. Y

As-so far described it will now beunderstood that upon rotation'of the crankshafts inY opposite directions, the

pair of xedly spaced pistons and the intermediate piston will be reciprocated in opposite directions, thereby alternately expanding and contracting the

chambers

96 and 98 in sequence. The expansion and contraction of these chambers constitutes the working strokes of the piston assembly.

From Figure 2 it will be further noted that intermediate the ends of the intermediate piston there is provided upon its exterior surface a circumferentially extending recess 186, and a further longitudinally elongated inner recess 192 is formed upon the inner surface thereof. The outer recess 160 provides a chamber between the intermediate piston and the wall of the cylinder, while the inner recess 102 provides a similar chamber between the interior of the intermediate piston and the exterior surface of the outer tube 66. A plurality of bores or ports 104 extend through the intermediate piston to establish communication between these two recesses.

Means are provided for lubricating the inner relatively moving surfaces of the telescoping concentric tubes, and of the intermediate piston as well as the other working parts of the engine. For this purpose, as will be best apparent from Figure 2 in conjunction with Figure 4, it will be understood that each of the

crankcase housings

42 and 44 has mounted in the bottom or sump thereof a lubricating gear pump assembly which is designated generally by the numeral 110 and is of a conventional design, the same including an inlet passage 112 communicating with the interior of the crankcase for receiving lubricant from the sump portion thereof, together with a lubricant discharge passage 114 by which lubricant is discharged from the gear pump. The gear pumps are driven from the

crankshafts

34 and 36 through the agency of gears 116 on each crankshaft which vgears rrie'sli' with the pump driving gear 118 as shown in Figure 4.

The lubricant discharge conduits 114 each communicate with the cylinder 2t? at its mid-portion and discharge into the previously mentioned exterior annular recess of the intermediate piston. From thence the lubricant under pressure passes through the ports 104 to the innerY recess 102, from whence it travels through Vthe slot 70 either directly to the interior of the outer tube' 66 or by further means of the bores or ports 68 to the inner tube kof the interior of the latter. Thus, ythe lubricant is enabled to satisfactorily lubricate the exterior surface of the intermediate piston; the exterior surface of the outer tube 66 betweenA the latter and the intermediate piston; the adjacent surface of the concentric telescoping tubes; the pins 6i), 72 and 62; and will then ow from th open ends of the cylinder into the two crankcases to thus lubricate the crankshafts and the working parts therein.

Further means are provided for supplying combustion components to the interior of the

combustion chambers

96 and 98 of the engine, for igniting these components and for educting combustion products therefrom.

Although the construction of the engine and its mechanisrn for producing expansible working chambers is applicable to other apparatuses and internal combustion engines, and to other types of engines and cycles of operations, it is especially applicable as regards the economy of fuel and the obtaining of a low ratio of weight to horsepower developed, for use with the well-known two cycle diesel operation.

For that purpose there are provided a pair of air compressorsk 129 each of which is secured as by fastening bolts 122 tov a mountingeange' 124 projecting laterally from the cylinder at the inner end of the working chamq bers 96' and 98.' These compressors'may be of any desired character but are preferably of the conventional centrifugal compressor type, being shown more clearly in Figure y6. Inasmuch as the details of the blower or cornpressors 12d) form no partY of the invention claimed herein', and since the invention asclaimed is not limited to anyparticular construction ofthe air compressors, a

furtherV description of the same is-deerned'to be unneces-4 sary fory the purposes of this invention. However, there is provided an annular manifold 126 surrounding the cylinder 29 at each of the

combustion chambers

96 and 98 and a plurality of air inlet ports 128 establish communication from the interior of this manifold to the interior of the cylinder and the combustion chambers therein.

The compressors are supported as above described upon the wall of the cylinder, but their rotors 130 are xedly secured to the connecting shaft 54 previously mentioned. Thus, the means which interconnects the two crankshafts for contra-rotation is employed to drive the pair of compressors, each of which supplies compressed air to one of the working chambers of the engine.

At the outer end of each of the

combustion chambers

96 and 98, the crankcase is encircled by an exhaust manifold 1.4i) which communicates with the interior of the working chamber as by a series of circumferentially spaced exhaust ports 142, this arrangement being shown best in Figure 5. The exhaust manifolds are connected by exhaust pipes 144 to a common exhaust mufer 146 having one or more exhaust discharge pipes 148. This mufler may be of any conventional design but of course must possess sucient capacity to handle the combined exhaust products of the two

combustion chambers

96 and 98. Inasmuch as the details of the muffler form no part of the invention claimed herein, it has not been deemed necessary to further illustrate or describe the same.

In order to supply fuel to the combustion chambers and effect ignition of the same therein there is provided any conventional type of fuel injection pump designated generally by the numeral 169. One such pump is provided for each of the combustion chambers, the pumps being mounted upon the

compartments

42 and 44 and having fuel delivery lines 162 which extend from the pumps into the

combustion chambers

96 and 98 at substantially the midportion of the same. if desired, any conventional type of fuel injection nozzles can be provided at the exit of these fuel delivery conduits for appropriately discharging and spraying the liquid fuel into the interior of the combustion chambers.

Conveniently, the pumps each include a plunger or piston 164 which is operated by a cam 166 formed upon the crankshafts 34E and 36 in the

compartments

42 and 44 respectively. It will of course be understood that the operation of the injection pumps is appropriately timed With respect to the position of the reciprocating pistons to inject the fuel into the compressed air in the combustion chamber in properly timed relation to effect ignition by compression existing in the chamber and thus producing the power stroke of the pistons.

It will further be observed that the compressed air inlet ports are so positioned as to be controlled by the intermediate piston, and thus will be opened at the time the associated working chamber would have reached its maximum volume, at which time the other piston Si) or 82 will also have opened the exhaust ports thus permitting the combustion products to discharge from the working chambers. The incoming compressed air will thus facilitate scavenging of the exhaust products upon the completion of the working stroke, and will charge the chamber with compressed air in readiness for the following compression stroke. When the compression stroke has been substantially completed and the Working chamber reduced to its minimum volume, the cam 166 will deliver the timed injection of fuel into the compressed air, thus producing ignition and combustion and intiating the next working stroke of the engine.

In the position shown in Figures 2 and 3, the various pistons are at their intermediate positions during their operation. In the position shown in Figure 7, it Will be observed that the combustion chamber 96 has completed its working stroke, since the air inlet ports are open and compressed air is being discharged thereinto scavenging the cylinder and driving exhaust products out of the open exhaust ports. At the same time, the combustion charnber 98 has completed its compression stroke and the associated fuel injector pump has injected a fuel charge thereinto and initiated combustion therein. Upon rotation of the two crankshafts, the pistons will then assume the position shown in Figure 8 at which time it will be observed that the left hand chamber 96 will have completed its compression stroke, while the right hand chamber 98 will have completed it power stroke.

It will be further noted that with this engine the relative displacement of the pistons in their working chambers is twice the throw of their crankshafts since both the pistons move simultaneously towards and from each other in a given working chamber. Further, since each piston in a working chamber is connected to both crankshafts, the force of the explosion will be equally imparted to both crankshafts simultaneously thus producing a balancing of the forces involved as well as of the reciprocating and reversing inertias and masses of the pistons.

It will be further noted that as a pair of pistons completes its compression stroke, their inertia is cushioned as the pistons reverse their reciprocation by virtue of the compressed gases therebetween, and the kinetic energy thus absorbed by the compressed gases is returned to the pistons as they recede from each other. Thus the transmission of strains to the transmission mechanism of the engine is reduced to a minimum as well as the inertias and shocks arising from the usual reversal of pistonV reciprocation.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

l. An internal combustion engine comprising a cylinder, a crankcase secured to each end of said cylinder, a pair of parallel crankshafts each journaled in one of said crankcases, means connecting said crankshafts for reverse rotation, a pair of spaced pistons rigidly connected together and slidable in said cylinder and connected to one of said crankshafts, an intermediate piston connected to the other crankshaft and slidably disposed in said cylinder between said pair of pistons, the spaces in said cylinder between the opposite ends of said intermediate piston and said pair of pistons dening a pair of combustion chambers, means for delivering combustion components to said chambers in succession, for igniting said components and for exhausting combustion products therefrom, a pair of telescoping tubes each connected to one of said crankshafts, means connecting one tube to said intermediate piston, means connecting the other tube to said pair of pistons, said telescoping tubes providing an opening extending longitudinally therethrough and communicating with said crankcases, whereby the volume displaced by one of said spaced pistons upon movement of the latter towards the adjacent crank-. case is substantially equalled by the simultaneous move-` ment of the other spaced piston away from its adjacent crankcase thereby maintaining substantially equal and constant air pressure in each of said crankcases.

2. An internal combustion engine comprising a cylinder, a -crankcase secured to each end of said cylinder, a pair of parallel crankshafts each journaled in one of said crankcases, means connecting said crankshafts for reverse rotation, a pair of spaced pistons rigidly connected together and slidable in said cylinder and connected to one of said crankshafts, an intermediate piston connected to the other crankshaft and slidably disposed in said cylinder between said pair of pistons, the spaces in said cylinder between the opposite ends of said intermediate piston and said pair of pistons defining a pair asa-6,14@

`f coniustion chambers, means for delivering combustioncornponents to said chambers in succession, for igniting Said components and for exhausting combustion produetsrther'efrom, `a pair of telescoping tubes each connected to one of said crankshafts, means connecting one tubeA to said intermediate piston, means connecting the' other tube -to said pair of pistons, said telescoping tubes providing an opening extending longitudinally therethrough and communicating with saidpcrankcases, means for circulating lubricant through said telescoping tubes and Said crankcases. A Y 3.l An internal combustion enginecomprising a cylinder, a crankcase secured to each end of said cylinder, -a pair of parallel crankshafts each journaled in one of said crankcases, means connecting said crankshafts for reverse rotation, a pair of spaced pistonsr rigidly connected together and slidable in said cylinder and connected to one of said crankshafts, andintermediate piston connected to the other crankshaft and slidably disposed in said cylinder between said pair of pistons, the spaces in said cylinder between the opposite ends of said intermediate piston and said pair of pistons denning a pair of combustion chambers, means for delivering combustion components to said chambers in succession, for igniting said components and for exhausting combustion products therefrom, a pair of telescoping tubes, means connecting each tube to one of said crankshafts, each of said pistons having an axial Iopening therethrough, the outer of said tubes being disposed in all of the openings of said pistons and rigidly connected to Said pair of pistons, said outer tube having a longitudinally extending diametrical slot in a mid-portion thereof, a pin slidably disposed through said slot and secured to both the inner of said tubes and to said intermediate piston, said telescoping tubes providing an Vopening extending longitudinally therethrough and communicating with said crankcases, whereby the volume displaced by one of said spaced pistons upon movement of Ythe latter toward thel adjacent crankcases is substantially equalled by the simultaneous movement of the other spaced piston awayfrom its adjacent crankcase thereby maintaining substantially equal and constant air pressure in each of said crankcases.

4. An internal combustion engine comprising a cylinder, a crank secured to each end of said cylinder, a pair of parallel crankshafts each journaled in l,one of saidV crank cases, means connecting Said crankshafts for reverse rotation, a pair of spaced pistons rigidly connected together and slidable in said cylinder and connected toY one of said crankshafts, an intermediate piston cbnf nected to the other crankshaft and slidably disposed in said cylinder between said pair of pistons, the spaces in said cylinder between the opposite endsrof said intermediate piston Vand said pair of pistons deiinng aV pair of lcombustion chambers, means for delivering combustionV components to said chambers'l in successiom for igniting said componentsand for exhausting combustion products therefrom, a pairof telescoping tubes, means connecting each tube to one of said crankshafts, each of Said pistons having an axial opening therethrough, the outer of said tubes being disposed in all of the openings of said pistons and rigidly connected to said pair of pistons, said outer tube Vhavinga longitudinally extendingdiametrical slot in a mid-portion thereof, a pin slidably disposed through Said slot andV secured to'brothV the inner of said tubes and to said intermediate piston, an annular recess 'upon the exterior'surface of said intermediate piston, ports establishing communication Vbetween said re-` cess yandthe axial opening of said intermediate piston, ports in said inner tube vcommunicating theinterior of the latter with said slot and with said'interfme'diate piston ports, tbe interior of said tubes communicating with said crankcases, means for circulating lubricant .fromsaid crankcases tosaid recesses and from thence through said fnbes to said crankcases.

5,. An internal'combustion engine comprising a cyliiidrer,v a crankcase secured to each end of said cylinder, a pairfo'f parallel crankshaits each journaled in one of Said crankcases, means connecting said crankshafts for reverse rotation, a pair of spaced pistons rigidly connected together and slidable in said cylinder and connected to one of Said crankshafts, an intermediate piston connected to the other crankshaft and slidably disposed in said cylinder between said pair of pistons, the spaces in said cylinder between the opposite ends of said intermediate piston and said pair of pistons defining a pair of combustion chambers, means for delivering combustion components and for exhaustingcombustion products therefrom, said last mentioned means comprising air blowers driven fromrsaid connecting means and delivering cornpressed air from each blower to one of said combustion chambers fuel injection means operated each by one of said crankshafts and injectingfuel into a combustion chamber and effecting ignition therein and exhaust means educting products of combustion from each combustion chamber, a pair of telescopingtubes each connected to one of said crankshafts, means connecting one tube to said intermediate piston, means connecting the other tube to said pair of pistons, said telescoping tubes providing an opening extending longitudinally therethrough and communicating with said crankcases, whereby the volume displaced by one of said spaced pistons upon movement of the latter towards the adjacent crankcase is substan- Vtially equalled by the simultaneous movement of the other spaced piston away from its adjacent crankcase Y a [pair of parallel crankshafts each journalled in one of said crankcases, means connecting said crankshafts `for reverse rotation, a pair of spaced pistons rigidly connected together and slidable in said cylinder and connected to one of Said crankshafts, and intermediate piston connected to the other crankshaft and slidably disposed in said cylinder between said pair of pistons, a pair of telescoping tubes each connected to one of said crankshafts, means Yconnecting one tube to said intermediate piston, means connecting the other tube to said pair of pistons, said telescoping tubes providing an opening extending longitudinally therethrough and ycommunicating with said crankcases, whereby the volume displaced by one of saidspaced pistons upon movement of the latter towards the adjacent crankcase is substantially equalled by the simultaneous movement of the other spaced piston away from its adjacent crankcase thereby maintaining substantially equal and constant air pressure in each of said crankcases.

.7. The combination of claim 6 including means for delivering combustion components to the combustion chambers of said engine, Said last mentioned means comprising air blowers Idriven from said connecting means and delivering compressed air from each blower to the combustion chambers, fuel injection means operated each by one of said crankshafts and injecting fuel into a combustion chamber and effecting ignition therein Vand exhaust means educting Vproducts of combustion from each combustion chamber.

References Cited in the le Vof this patent UNITED STATES PATENTS '1,106,043' trauert ;ug. 4, 1914 1,257,104 Olson et al. 2 1Feb. 19, 1918 1,707,897 Bizet' 1 Apr. 2, 1929 .2,093,433 Greene Sept; 2l, 1937 2,180,898 Frazer Nrn/.21, 1939 2,381,165 Eird t 1943 2,781,748 stuck@ 1-eb. 19, 1957 l FOREiGN PATENTS l841,118 France Feb. 1, 1939