USRE21031E - Lubrication system for internal - Google Patents

Description

March 14, 1939. M, J. scHNK JUBRICATION SYSTEM FOR INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet 1 Original Filed Oct. 17, 1929 .www .EUNIS-juill /H j March 14, 1939. M. J, s'cHENK R- 21,031

LUBRIGATION'SYSTEM FOR INTERNAL COMBUSTI'ON ENGINES Original Filed O ct. 1'7, 1929 v 4 Sheets-Sheet 2 .ffii f f. fy f.

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March 14, 1939.'

M. J. vsel-Erm l LUBRICATION SYSTEM FR INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet original Filed oct. 17. w29

March 14, 1939. M. .J scHENK R 21,031

LUBRICAT'ION'SYSTEM FOR INTERNAL COMBUSTION ENGINES Original Filed Oct. 17, 1929 4 Sheets-Sheet 4 rIl `Reissued Mar. 14, 1939 PATENT OFFICE LUBRICATION SYSTEM FR INTERNAL COMBUSTION ENGINES Martin J. Schenk, Chicago, Ill., assignor, by direct and mesne assignments, of thirty-three and one-third per cent to It. Picard, Chicago,

Ill.

Original No. 1,815,868, dated July 21, 1931, Serial No. 400,383, October 17, 1929. Application for reissue December 27, 1938, Serial No. 248,009

22 Claims.

come into such wide commercial and militaryv use.

Engines of this type have'been generally accepted as the most practical type of engine for aeroplanes, and their acceptance has been due to the fact that they vfurnish a maximum of power per pound of engine weight, their iightness being dueto the lesser amount of metal needed in the cylinders than in enginesof the water cooled type, and to the fact that no cooling radiators and fluid are necessary. However, certain drawbacks to the use of radial engines have been encountered and chief among these are the.

difiiculty in' properly lubricating the entire valve gear and properly coolingthe valves.

These drawbacks have been such as to necessitate the disassembly of the'entire valve gear after every'ilfteen hours of iiying time in order to thoroughly lubricate the same and have further made it necessary to completely overhaul 25 zthe engine after 200 hours oi.' use-in order to grind the valves, and replace any such -valves as may have become burned or warped. It has been impossible, up to .the present time, to carry out any long sustained iiights Without rigging up an auxiliary lubricating device for. the valves which can be controlled from the cockpit o f the plane, or lubricating the `valves with a manually operated pressure gum-which means that it is necessary for the flight mechanic to climb out 35 of `the cockpit of the plane to the engine and attach the gun to each of the lubricating nipples provided on the rocker arms'ofv the valve gear. l

These expedients have proved both inefiicient and dangerous, as it is impossible to thoroughly 40 lubricate all parts of the valve gear by these methods.

The object of my invention is to overcome the vabove-mentioned.troubles and to? thoroughly lubricate the valve gear and cool the valves auto- .matically.

1- Further my improvementis made an integral i part yof the lubrication system now Vembodied in Ir-the type of eng-ine referred, to and isfso arranged as to be applicable to'engines ,nowvin service with f but few changes of fparts.'

The above object is attained to the valves in orderI to` cool' the sama-after lbyl forcing oil,v Y under pressure, to all parts of the valve gear and employed in the usual lubrication system which has heretofore been conilned `to the crank case of the engine.

A complete understanding oi' my invention may be had by reference to the accompanying drawings, of which:

Fig. 1 is a face view of an engine embodying my improvement;

Fig. 2 is a vertical section oi' the same engine;

Fig. 3 is a vertical section through a cam follower;

Fig. 4 is a section through line L-I of Fig. 3;

Fig. 5 is a section through line 5--5 of Fig. 3;

Fig. 6 is a section through line 6 6 oi Fig. 3;

Fig. 7 is a detail view in section. showing the valve gear for one valve on the cylinder head;

Fig. 8 is a longitudinal section of a valve showing the oil circulating passages:

Flg.- v9 is a section through one of the valve' rocker arms;

Fig. 10 is a section through 8; and g Fig. 1l is a section through the valve adjusting means showing the oil passages therein'.

. Myinvention is illustrated as applied to a nine cylinder, radial, air-cooled engine in which the cra-nk case-is designatedby the numeral I, the cylinders, which are disposed radially` about the crank case,vas 2 andthe rocker arm boxes as 3, there being two such boxesto each cylinder, one for the exhaust valve and one for the intake valve. Inasmuch as the mechanism operating each valve andthe system for lubricating such \mechanism is the` same throughout the engine it will only-be necessary to describe the mechaune llt-#loef Fig.

' nism as applied to a single valve.

Each box is providedwithan oil tight cover 4 which can be' removed to permit adjustmens to the valves, the remainder of the valve box being cast integral with the cylinder head. Within each rocker arm box is a rocker arm 5 pivoted about a shaft 0.4 so as tooperate `the valve 1 lwhich is normally. held in a closed position by springs 0. Each rockerarm is operated f by means of a hollow push rod 9 having a rounded head- I0 which is drilled to permit the passage of oil therethrough. The oil passage in thepush rod communicates with an oil passageV lli in the .rocker arm, whichpassage` alsogfeeds the roller bearing on,l which Ythe `roclrineravrln is.' journaled, and the valve adjusting.l means which .consists of a threaded screw member: I2 havinga hemi- .spher-ical concavity ,inthe A.lower end thereof. The screw member i 2 is heldin itsadjusted position by means of a .locking nut lian'dfis provided with an annular groove I4 about its median portion which communicates with oil passages within the screw member and with the oil passage II in the rocker arm. Between the lower end of the acusting screw I2 and the top of the valve 1 there is provided a friction reducing member I5 having an oil passage therethrough. This anti-friction member is rounded on top to co|ncde with the concavity in tue adjusting screw I2 and is provided with a plane surface on the bottom for engagement with the stem of the valve 1.

'Ihe valve 1 has been specially designed to meet the need for a valve which can be readily cooled, and to this end is so constructed as to permit the passage of cooling oil therethrough. a 'I'he valve is provided with an inlet passage I6, a hollow chamber I1 in the head and an outlet passage I3. By reference to Figs. 8, 9 and 10, the details of the valve construction are readily apparent.

The main portion of the valve consisting of the stem and head is first formed, the oil passages I3 and I3 are then drilled in the stem, after which a disc 1a is pressed into the cavity I1, and forms an oil tight joint with the undercut shoulder on the valve.

The hollow push rod 9 is provided at its lower extremity with an anti-friction member Ia having a rounded end which engages in a concavity in the top of a cam follower. 'I'he member Ila is also drilled to permit the passage of oil therethrough. The cam follower consists of upper and lower parts I9 and 23 between which is placed the spring 2|. The upper portion I9 of the cam follower has drilled therein the cylindrical cavity 23. 'I'he lower portion 20 of the cam follower is turned down to form the protuberance 24y which tits into the cavity 23 in which is placed the spring 2|. 'Ihe upper part of the cam follower is drilled to form the oil passages 22 and the lower part is drilled to form the connecting passages 25 and 28. The cam is designated by the letter C and the cam follower and the rest of the valve gear is operated-through the medium of the roller 21 journaled on a shaft 23 which in turn is mounted in a slot in the lower portion of the cam follower. Oil is supplied to the roller by housing 3| which is fixed in the crank case I and .return of oil tothe crank case.

is restrained against rotation by pin 2 Ia. Through the housing 3| is drilled a passage 32 for the 'Ihe housing 3| is further provided with a hollow internally threaded pipe connection 33, into which is threaded a connection 34 communicating with a manifold 35.- Within the connection 33 is placed a ball check 36 which is prevented from closing the port to the oil passages in the cam follower by means of a pin 31. 1

Between the top of the cam follower housing and the bottom of the rocker arm box 3 there is provided a telescoping push rod cover 33, which can readily be applied to the push rod between the cylinder and the cam follower housing.

From the lowest portion of each rocker arm box a pipe 39 leads to a manifold 4I for returning the oil which has been through the system back to an oil sump 4| from which itis drawn through the strainer 42 and a pipe 43. The sump is provided at its lowest extremity with a drain plug through which accumulated dirt and water which has entered the system may be withdrawn. This manifold 4|I surrounds the crank shaft, the

upper portion lying between the rocker arm xes 3 and the crank shaft, while the lower portion of l the manifold is outside of the boxes 3, so that each of the boxes 3 is above anadjacent portion of the manifold, whereby the oil is drained by gravity from each of the boxes 3 to the manifold 40 through its pipe 33, see Fig. 1. y

Within the crank case I is shown a pipev 44 (Fig. 2) carrying oil from the usual pump (not shown) to the crank shaft. From this pipe 44 is led another pipe 45 which feeds oil to the manifold 35.

Having described the various parts of my improved system in detail, I shall now proceed to describe the operation of the system in its entirety.

As before stated, the oil under pressure is conveyed under pressure from the usual pump to the crank shaft and allied parts through pipe 44 but as this does not form a part of my invention it will be unnecessary to describe the same. From the pipe 44 the oil is also conveyed to the manifold 35, which is on the outside of the crank case, by means of the pipe 45. From the manifold 35 outlets are provided to each of the cam follower housings 3|, the ball checks 36 being unseated by the oil, see Fig. 3. After the oil has enteredthe housing 3| part of it passes through the groove 29 in the lower portion of the cam follower downwards to lubricate the roller 21, some of the oil leaking out and lubricating the face of the cam C. 'Ihe remainder of the oil enters the passages 25 and 23 which discharge into the cavities 23. From the cavitiesr 23 the oil passes through passages 22 in the upper portions of the cam followu ers, lubricates the friction surfaces between the cam followers and the lower ends |8a of the push rods. 'Ihe oil now flows up through the hollow push rods 9 by means of the passages in' the upper extremities of the push rods, the oil passes into and through the passages I| in the rocker arms 5 lubricating the friction'surfaces between the upper ends of the push rods and the rocker arms and also the roller bearings in which the rocker arms are journaled, from the passages the oil is conveyed through the passages in the valve adjusting screws I2 and from thence throughthe passage in the anti-friction members I5 between the adjusting screws andthe tops of the valve stems. The oil then passes through the intake channels I6 in the valve stems, circulates within the hollow chambers I1 of the valves and cools the same and then ows through the passages |3 and is discharged into the valve boxes, thereby lubricating the valve stems.

From the valve boxes the oil ows through the drain tubes 39, placed in the lowest portions ofthe valve boxes, into the manifold 4l and thence to the oil sump 4| from which it is drawn'through pipe 43by means of a scavenge pump (not shown) and is returned to the oil reservoir in the fuselage of the plane. The return pipe 43 must necessarily be placed'below the level of the rocker boxes of the lowermost cylinders in order to prevent 'the flooding of the rocker boxes. Any oil which may have found its way into the push rod covers 33 of the top cylinders will drain by gravity into the crank case by way of the oil passage 32 drilled in the cam follower housings and from the crank case to the sump in the usual manner.

The lower portions of the cam followers are held against the cam by means of the spring 2| within the followers, This spring will also cause the upper portions of the cam followers to be held against the lower ends of the push rods, the

arms and nally the opposite ends of the rocker arms against the tops of the valve stems. This construction, it will readily be seen, prevents the leakingof the oil at the points referred to other than that necessary to properly lubricate the friction surfaces. 'I'he springs 2| are of the compression type and operate against the force of the springs 8 which -hold the valves in their closed positions. 'I'he `force of the springs 2l is only about six pounds apiece whereas the force' oi the springs 8 total about 45 pounds when vthe valves are closed and about 70 pounds when the valves are held open by the cam and intermediate valve gear so that the action of the spi-ings 2| can in no way interfere with thenormal operation -of the valves.

There is provided in the valve geara certain` amount of play to compensate for the expansion of the cylinders, push rods and cam followers, enough play being allowed so that there exists about .01" between the members I5 and the valve stems when the motor is cold and about .06" when the motor is hot. As can readily be seen, 'this play -is all taken up between the upper and lower portions I9 and 20 of the cam followers and isapt to form a slight pumping actionwhich would act against the force of the oil pump. This reaction against the pump is prevented by the ball check 36 in each of the cam follow'er housings, which, in levent of any back pressure will seat against the ends of the pipes 3l. It

'f is preferable to allow more clearance than above specifled'and to increaseithe cam lift proportionately so that a greater pumping action is caused between the upper and lower port-ions of the cam followers thus creating/a greatere pres-y sure to exist in the system/between the ball checks and the-outlets in the valve stems'. It is also evident that the springs 2| and the oil in the chambersf23 will provide a cushioning effect on the various parts of the valve gear as the valves are actuated.

From the foregoing `description it is evident that myimprovement will thoroughly and adequately lubricate all parts of the valve gear and cool the valves so that flights of the longest duration can be safely carried out without fear of motor failure due to insufficient lubrication and the life of a motor between overhauls can be lengthened from 200 hours to 1000 hours of flying time. 'While-I have, in the-foregoing description, described my invention in its preferred form, it is evident `that many changes might be made in its construction and operation without departing from the scope ofthe invention. e

- Having now described my invention, what I the lubricant delivered to the joints when the push rod is moved in one direction, without bffecting the pressure in the supply. y

2. A lubricating system for internal combustion engines, having valves, a rocker arm for each valve enclosed wit-hin a chamber, a push rod for each rocker arm, a lubricant supply, and means for delivering lubricant under pressure to the joints between the rocker arm and push rod and the valve and rocker arm and from there to its chamber, and means for returning oil from each chamber back to the supply. I

3. A lubricating system for internal combustion engines having a plurality of radially disposed cylinders surrounding the crank shaft, valves for each cylinder, a rocker arm for each valve, a casing for each rocker arm, a push rod for each valve, a 'lubricant source, a lubricant supply means for delivering lubricant under pressure from the lubricant source to the joints between each push rod and its rocker arm and each valve and its rocker arm, and a downwardly extending drain from each casing for returning the lubricant back to said source.

4. A lubricating system for internal combustion enginesl having a plurality of radially disposed cylinders surrounding the crank shaft, valves for each cylinder, a rocker arm for each valve enclosed within a chamber, a push rod for each rocker arm, a manifold surrounding the crank shafta source of lubricant supply, means for delivering lubricant under pressure from said source to said manifold, connections from said manifold for delivering lubricant to the joints between each rocker arm and its n manifold for delivering lubricant to the joints between each rocker arm and its push rod and each rocker arm and its valve, a second manifold surrounding the crank shaft, a downwardly extending lubricant return connection from each rocker arm chamberto said second ymanifold to drain said chamber by gravity, and-a 'common lubricant connection from the second manifold to the source of lubricant.

6. A lubricating system for internal combustion engines having reciprocating valves, a rocker arm for each valve,\a bearing for the rocker arm, a hollow push rod for the rocker arrn,` means for actuating the push rod, a passage for lubricantin the rocker arm communicating with the hollow' push rod and the bearing, a second passage for lubricant in the rocker arm communicating with the bearing and the joint between the rocker arm and the end of the valve stem, means for causing lubricant to first flow through the push rod and then through the rocker arm to the' joint between the valve stem and rocker arm and other means for increasing the pressure of the lubricant in thesystem when the push rod is moved in one direc tion.

7. A lubricating system for an internal combustion engine valve gear having Ia reciprocating valve provided with a stem, a rocker arm for actuating the valve, a bearing inthe rocker arm, a hollow push rod for -actuating the rocker arm, passages for lubricant Within the rocker arm comsy municating with the hollow push rod, means for actuating the push rod, the bearing and the joint between the valve stem `and rocker arm, there being a chamber in the valve, a passage in the valve stem communicating with the passage in the lliv rocker arm at the joint between the rocker arm I and stem, there being an outlet passage from the chamber in' the valve stem. means for continuously forcing lubricant through the said passages and the chamber in the valve for cooling the valve andlubricating the rocker arm bearing, the joints between the rocker arm and push rod and the joint between the'rocker arm and the valve stem, means for causing lubricant to rst flow through .the push rod and then through the rocker arm to the joint between the valve stem and rocker arm, and other means for increasing the pressure of the lubricant in the system when the push rod is moved in one direction.l

8. A lubricating system for internal combustion engine valve gear for a reciprocating valve,'comprising a rocker arm for opening theyalve, a push rod for actuating the'rocker arm, a cam, a two partfoliower between the cam and push rod, a housing for the follower parts, a relatively light spring between the follower parts,'a relatively heavy spring for moving the valve to its closedY position, the light spring tending to separate the follower parts and maintain the valve gear elements in engagement with each other and with k the valve, there being a space between said follower parts when the valve is closed, adjustable means for varying thesize of such space, means for feeding lubricant to said space, a check valve for preventing the retrograde movement of lubricant from said space when the follower parts are moved towards each other, there being lubricant passages from said space to the joints between the Y rocker arm and the push rod and the joint between the valve and rocker arm, whereby lubricant is continuously delivered to said joints by the combined action of the lubricant feeding means and the relative movement of the follower parts.

9. A lubricating system for internal combustion engine valve gear for a reciprocating valve, comprising a rocker arm for opening the valve, a push rod for actuating the rocker arm, a cam, a two part follower between the cam and push rod, a housing for the follower parts, a relatively light spring between the follower parts, a relatively heavy spring for moving the valve to its closed position, the light spring tending to separate the follower parts and maintain the valve gear elements in engagement with each other and with the valve, there being a space between said follower parts when the valve is closed, adjustable means for varying the sizeof such space, means for feeding lubricant to said space, a check valve for preventing the retrograde movement of lubricant from said space, there being a continuous lubricant passage from said space through the push rod, and the rocker arm to the joint between the rocker arm and the valve, said two part follower acting as a pump when the push rod is moved in one direction.

A lubricating system for internal combustion engine valve gear for a reciprocating valve having a stem and a head, comprising a rocker arm for opening the valve, a push rod for actuating the rocker arm, a cam, a two part follower between the cam and push rod, a housing for the follower parts,` a relatively light spring between the follower parts, a relatively heavy spring for moving-the valve to its closed position, the light spring tending to separate the follower parts and maintain the valve gear elements in engagement with each other and with the valve, there being a space between said follower parts when the valve is closed, adjustable means for varying the size of such space, means for feeding lubricant to said space, a check valve for preventing the retrograde movement `of lubricant from said f space, there being a chamber in the Vvalve head, an outlet passage leading-from said chamber, there being continuous lubricant passages from said space `be tween the follower parts through the push rod, the rocker arm and valve stem to the chamber in the valve, whereby lubricant is continuously delivered to all of the joints of the valve gear for lubricating said joints and through the chamber` in the valve for cooling the valve, said two part follower acting as a pump when'the push rod ls moved in one direction. Y

ll. A lubricating system for reciprocating V valves of an internal combustion engine having a stem, a rocker arm for moving the stem, a push rod for actuating the rocker arm, a follower, a cam for actuating the followena roller mounted in the follower in'engagement with the cam, a housing for the follower, means for delivering lubricant to the housing, there being an oil passage for delivering lubricant from the housing to the roller,` and there also being a continuous lubricant passage from said housing through a portion of the follower, the push rod andthe rocker arm to the joint betweenthe rocker arm and the valve stem.

- 12. A lubricating system for internal combustion engine valve gear for a reciprocating valve including a two part follower, a housing for the follower, means for adjusting the valve gear to -provide a space between the follower parts when the valve is closed, means for supplying oil to the space between the follower parts, oil connections from said space to the joints in the valve gear, means for moving one of said parts toward the other and then actuating the valve, and means for preventing the movement of the oil from between said parts to the oil supply means, whereby said oil is forced through the oil connections to the joints in the valve gear.`

13. A two part follower for a valve gear lubricating system, a housing for the follower parts,

means'forgsupplying oil under pressure within the housing between the follower parts, means for conducting oil from between said follower parts to the jointsof the valve gear, means for actuating the follower parts, and means for preventing they oil from flowing into the supply means when the follower parts are moved toward each other, whereby the pressure of the oil in the system between the housing and the joints 15. A lubricating system for internal combus tion engines having a plurality of radially disposed cylinders surrounding the crank shaft, valves for each cylinder, there being a separate chamber inclosing each valve actuating mechanism, a follower for actuating each valve mechanism, a housing inclosing each follower, means for delivering oil under pressure to each follower housing, means for delivering oil from each housing to the joints of the valve mechanism actuated' thereby, a manifold surrounding the crank shaft of the engine, means for conducting the oil by gravity from each valve mechanism chamber to said manifold, and means for returning the oil from the manifold to the oil delivery means.

16. A lubricating system for internal combustion engines having a plurality of radially disposed cylinders surrounding the crank shaft, valves for each cylinder, valve actuating mechanism for each valve, each of said valve actuating mechanisms being enclosed within a casing, means for delivering oil under pressure to each valve actuating mechanism, a return oil manifold surrounding the crank shaft, the upper portion of said manifold lying between the valve mechanism chambers and the crank shaft while the lower portion thereof is beyond the lower valve mechanism chambers, drain pipes extending downwardly from each of said chambers to the manifold, and means for returning oil from the manifold to the supply.

17. An automatic valve gear lubricating system for internal combustion engines of the radial type having a centrally arranged crankcase, a plurality of radially disposed air-cooled cylinders surrounding the crankcase, valves for each cylinder, and valve-actuating mechanism for each valve including a hollow rocker arm at the outer end of each cylinder in operative engagement with the valve, a hollow radially disposed push rod in operative engagement with the rocker arm, a hollow cam followerI in operative engagement with the push rod, and a guide for the cam follower, the push rods being located exteriorly of the cylinders in spaced relation to the latter, and the cam follower guides being located in the crankcase at the inner ends of the push rods; said lubricating system comprising means for supplying oil under pressure, means for conducting said oil to the cam followers through openings in the side of the cam follower guides, means for conducting said oil outwardly `through the cam followers to joints of all the push rods and rocker arms, oil-tight enclosures for the rocker arms at the outer ends of the cylinders, oil-tight tubes extending between the rocker arm enclosures and the cam follower guides, about the push rods in open communication with said enclosures, downwardly inclined pipes at the outer ends of the cylinders in communication at their upper ends with the lower portions of the rocker arm enclosures for draining by gravity from the enclosures oil discharged from joints of the valveactuating mechanisms, a common oil return beneath the crankcase between the two lowermost rocker arm enclosures into which the oil drained through all of said pipes flows, and a pump for causing the oil from said return to flow back to the oil supply means for recirculation.

18. An automatic valve gear lubricating system for internal combustion engines of the radial type having a centrally arranged crankcase, a plurality of radially disposed air-cooled cylinders surrounding the crankcase, valves for each cylinder, and valve-actuating mechanism for each valve including a'hollow rocker arm at the outer end of each cylinder in operative engagement with the valve, a hollow radially disposed push rod in operative engagement with the rocker` lation to the latter, and the cam follower guides being located in the crankcase at the inner ends of the push rods; said lubricating system comprising means for supplying oil under pressure. means for conducting said oil to the cam followers through openings in the sides of the cam follower guides, means for conducting said oil outwardly through the cam followers to joints of all the push rods and rocker arms, oil-tight enclosures for the rocker arms at the outer ends of the cylinders, oil-tight tubes extending between the rocker arm enclosures and the cam follower guides about the push rods in open communication with saidk enclosures, downwardly inclined pipes at the outer ends of the cylinders in communication at their upper ends with the lower portions of the rocker arm en closures for draining by gravity from the enclosures oil discharged from joints of the valve- `leading downwardly from the lower endsA of the push rod tubes into the crankcase, through which ducts the oil discharged from the push rod joints `in the tubes flows by gravity into the crankcase.

19. An automatic valve gear lubricating system for internal combustion engines of the radial type having a centrally arranged crankcase, a plurality of radially disposed air-cooled cylinders surrounding the crankcase, valves for each cylinder, and valve-actuating mechanism for each valve including a hollow rocker arm at the outer end of each cylinder in operative 'engagement with the valve, a hollow radially disposed push rod in operative engagement with the rocker arm, a hollow cam follower in operative engagement with the push rod, and a guide for the cam follower, the push rods being located exteriorly of thercylinders in spaced relation to the latter, and

the cam follower guides being located in the crankcase at the inner ends of the push rods,

y said lubricating system comprising means for supplying oil under pressure, means for conducting said oil to the cam followers through openings in Ithe sides of the cam follower guides, means for conducting said oil outwardly through the cam followers to joints of all the push rods and rocker arms, oil-tight enclosures for the rocker arms at the outer ends of the cylinders, oil-tight tubes extending between the rocker arm enclosures and the cam follower guides about the push rods in open communication with said enclosures, downwardly inclined pipes at the ou'ter ends of all the cylinders which are located below the level of the center of the crankcase, which pipes are in communication at their upper ends with the lower portions of the rocker arm enclosures of said cylinders for draining by gravity from said enclosures oil discharged from joints of the valve-actuating mechanisms of said cylinders, a common oil returnvbeneath the crankcase between the two lowermost rocker arm enclosures into which the oil drained through all of said ,pipes flows, and a pump for causing the oil from said return to flow back to the oil supply means for recirculation, the cam follower guides for all the cylinders which are located above the level of the center of the crankcase being provided f with ducts leading downwardly from the lower ends ofthe push rod tubes into the crankcase,

` through which ducts oil discharged from the push surrounding the crankcase, valves for each cylinder, and valve-actuating mechanism for each valve including a rocker arm, at the outer end of each cylinder in operative engagement with the valve, a hollow radially disposed push rod in operative engagement with the rocker arm, a hollow cam follower in operative engagement with the push rod, and a guide for the cam follower, the

push rods being located exteriorly of the cylinders in spaced relation to the latter, and the cam follower guides being located in the crankcase at the inner ends of the push rods; said lubricating system comprising means for supplying oil, means for conducting said oil to the cam followers through openings in the sides of the cam follower guides, means for conducting said oil outwardly through the cam followers torjoints of all the push rods and rocker arms, oil-tight enclosures for the rocker arms at the outer ends of the cylinders, oil-tight tubes extending between the rocker arm enclosures and the cam follower guides about the push rods, and means for conducting by gravity baci:` to the oil supply means oil discharged from joints of the vaiveactuating mechanisms of all the cylinders located above the level of the center of the crankcase, said last mentioned meansincluding ducts in the cam follower guides for said cylinders, which ducts lead downwardly from the lower ends of the push rod tubes into the crankcase.

21. An automatic valve gear lubricating system for internal combustion engines of the radial type having a centrally arranged crankcase, a plurality of radially disposed air-cooled cylinders surrounding the crankcase, valves for each cylinder, and valve-actuating mechanism for each valve including a hollow rocker arm at the outer end of each cylinder in operative engagement with the valve, a hollow radially disposed push rod in operative engagement with the rocker arm, a hollow cam follower in operative engagement with the push rod, and a guide for the cam' follower,

the push rods being located Yexteriorly of the cylinders in spaced relation to the latter, and the cam follower guides being located ln the crankcase at the inner ends of the push rods; said lubricating system comprising means for supplying oil under pressure, means for conducting said oil to the cam followers through openings in the sides of the cam follower guides, means for conducting said oil outwardly through the camY followers to joints of all the push rods and rocker arms, oil-tight enclosures for the rocker arms at the outer ends of the cylinders, oil-tight tubes extending between the rocker arm enclosures and the cam follower guides about the push rods in open communication with said enclosures, downwardly inclined pipes at the outer ends of the.

cylinders in communication at their upper` ends with the lower portions of the rocker arm enclosures for draining by gravity from the enclosures oil discharged from joints of the valveactuating mechanisms, a common oil return beneath the crankcase between the two lowermost rocker arm enclosures into which the oil drained through said pipes ows, and a pump for causing the oil from said return to flow back to the oil supply means for recirculation,A the cam follower guides for all the cylinders Ywhich are located above the level of the center of the crankcase being provided with ducts leading downwardly from the lower ends of the push rod'tubes into the crankcase, through which ducts oildischarged from the push rod joints in the tubes flows by gravity into the crankcase, each of said cam followers being made in two spring-expanded pumplike parts between which the oil entering from the opening in the side of the cam follower guide iiows and is forced intermittently under momentarily increased pressure through the outer part of the cam follower into the push rod by the contraction of said parts incident to the operation of the engine.

22. An automatic valve gear lubricating system for internal combustion engines of the radial type having a centrally arranged crankcase, a plurality of radially disposed air-cooled cylinders surrounding the crankcase, valves for each cylinder, and valve-actuating mechanism for each valve including a hollow rocker arm at the outer end of each cylinder in operative engagement with the valve, a hollow radially disposed push rod in operative engagement with the rocker arm, a

hollow cam follower in operative engagement with the push rod, and a guidefor the cam follower, the push rods being located exteriorly of the cylinders in spaced relation to the latter, and the cam follower guides being located in the crankcase at the inner ends of the push rods; said lubricating system comprisingmeans for supplying oil under pressure, means ,for conducting said oil to the cam followers through openings in the sides of the cam follower guides, means for conducting said oil outwardly through the cam followers to joints of all the push rods and rocker arms, oil-tight enclosures for the rocker arms at the outer ends of the cylinders, oil-tight tubes extending between the rocker arm enclosures and the cam follower guides about the Apush rods in open communication with said enclosures, and means for conducting by gravity back to the oil supply means oil discharged from joints of the valve-actuating mechanisms, said last mentioned means including ducts in the cam follower guides for all the cylinders located above the level of the center of the crankcase, which ducts lead downwardly from the lower ends of the push rod traction of said parts incident to the operation of' the engine.

MARTIN J. SCHENK.

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