US1320531A

US1320531A - carroll

Info

Publication number: US1320531A
Authority: US
Publication date: 1919-11-04
Anticipated expiration: 1936-11-04

Description

D CARROLL.

ROTARY ENGINE.

APPLICATION FILED JUNE 22. l9l5- RENEWED MAR. 10.1919.

Patented Nov. 4, 1919.

ssg fial o 4 SHEETSSHEET .l. D. CARROLL.

ROTARY ENGINE.

APPLICATION FILED JUNE 22, 1915. RENEWED MAR. 10.1919.

Patented Nov. 4, 1919.

4 SHEETSSHEET 2.

J FM

J. D. CARROLL.

ROTARY ENGINE.

APPLICATION FILED JUNE 22. 19I5- RENEWED MAR. I0. 1919.

RENEWED MAR. 10,1919.

1 M 3 b 2 w E 3, m g 1 W W nnrr s JOHN D. CARROLL, OF VTEST LAFAYETTE, INDIANA, ASSIGNOR TO TURBO ROTARY ENGINE 00., OF EVANSVILLE, INDIANA, A CORPORATION OF SOUTH DAKOTA.

ROTARY ENGINE.

1,32a5si.

Application filed June 22, 1915, Serial No. 35,502. Renewed March 10, 1919.

T 0 all whom it may concern Be it known that I, JOHN D. CARROLL, a subject of the King of Great Britain, residing at West Lafayette, in the county of Tippecanoe and State of Indiana, have invented certain new and useful Improvements in Rotary Engines, of which the following is a specification.

This invention relates to rotary engines and has reference more particularly to that type of engine which employs eccentric pistons in the form of radial blades or vanes cooperating with a piston drum concentric and fast with the driven shaft, through which drum the piston vanes reciprocate radially during their rotation, and have wiping contact at their outer ends with the inner surface of the cylinder, and wherein the rotary piston drum carries radial flanges that overlap and form steam-tight joints with the ends of the working chamber of the cylinder, so as to constitute rotat ng side walls of the latter.

The general and primary object of the invention is to provide an improved engine of this .ype characterized by increased simplicity of construction, greater durability, and superior efficiency and reliability in operation; among the principal special advantages sought to be attained being the eli; ination of external bearin s for the driven shaft, an improved shaft construction that secures a more perfectrunning fit in its internal bearings and also affords an improved connection for the rotating drum thereto, a simplified and improved construction of rotating drum, an improved construction to relieve compression of steam after each piston vane has passed the exhaust port of the cylinder, an improved swivel bearing for the piston vanes, and a simplified and improved arrangement and organization for effecting the reversing of the engine.

The above named objects and advantages, with others of lesser importance, are secured through several novel structural features, all of which will be readily understood from a consideration of the accompanying drawings wherein I have illustrated my inven tion as embodied in a multiple cylinder eX- pansion engine of the eccentric piston type having three cylinders or units located side by side and operating on a common driven shaft extending through but journaled with- Specification of Letters Patent.

Patented Nov. 4, 1919.

Serial No. 281,837.

in the several cylinders of the series, the relatlve sizes and disposition of the units being such that lateral thrusts upon the shaft produced by the two outside or end cylinders are balanced and neutralized by the opposing thrusts of the intermediate cylinder which has a width equal to the combined widths of the end cylinders.

Referring to the drawings,

Figure 1 is an end elevation of my improved engine;

F 1g. 2 is a vertical axial section of the same;

Fig. 3 is a cross section taken on the line 3-3 of Fig. 2;

Fig. 4 is a cross section taken on the line 44 of Fig. 2;

Fig. 5 is a detail cross section taken on the line 55 of Fig. 2;

Fig. 6 is a group view illustrating the piston vanes employed in each cylinder and the relative grouping of said vanes in opposed pairs;

Fig. 7 is an elevation partly broken out and in longitudinal section of one of the swivel bearings for the piston vanes;

Fig. 8 is a view similar to Fig. 7 viewed from a point at right angles to the latter figure;

Fig. 9 is an end view of Figs. 7 and 8;

Fig. 10 is a cross section of the swivel bearing member;

Fig. 11 is a detail view illustrating the internal packing strips of the swivel bearing on a reduced scale;

Fig. 12 is an elevational view on a reduced scale of one of the packing rings for the heads or end walls of the piston driun.

In the accompanying drawings I have shown my improvements as embodied in an organization of engine employing three complete cylinders or units disposed side by side on a common driven shaft, since certain features of my improvements are applicable to such a multiple cylinder organization; but it will be apparent that other features of improvements are equally applicable to engines employing a single cylinder, and are in no wise dependent upon or peculiar to the multiple cylinder arrangement.

Referring to the drawings for a detailed description of the principal cooperating parts, 1 designates the driven steel shaft. That portion of said shaft which is within and between the end walls of the complete 7 engine housing is furnished with a cast iron lining 2, integral with which lining is a central cast iron disk or hub 3, the purpose of which will presently appear.

Rigidly mounted on the engine base .L are a series of three cylinders,a pair-of end cylinders 5, and an intermediate cylinder 6, this latter, as will be apparent from Fig. 2, having a width substantially equal to the combined widths of the end cylinders 5. The three cylinders are securely united by any suitable means, such as the bolts 7 passing through registering lugs 8 and 9 on the end and intermediate cylinders respectively. Covering the outer sides of the end cylinders 5'are stationary end walls 10 secured to said end cylinders 5 by any suitable means such as thebolts 7 extending through registering lugs 12 and 13 on said end walls and end cylinders respectively. On the outer sides of the end walls 10 are secured paclc ing glands 14lsurrounding the driven shaft 1 and serving to prevent escape of steam through the bearings of the shaft 1 in said end walls. The base 4, cylinders 5 and 6, and end walls 10, unitedly comprise the stationary outer housing or shell of the complete engine structure.

By reference to Fig. 2 it will be observed that the end cylinders 5 and intermediate cylinder 6 are all disposed eccentrically to the driven shaft 1, and that the eccentricity of the two end cylinders relatively to the shaft is diametrically opposite that of the intermediate cylinder. As the several cylinders and their contents are to a considerable extent structurally identical, being merely arranged oppositely relatively to the driven shaft, the same characters of reference will in so far as they are capable of application in common, be employed in describing the corresponding parts of the several cylinders.

Referring to Figs. 3 and 4:, it will be seen that each cylinder is so cored as to present a circular working chamber 15 which is ec-' centric to the shaft 1, these working chambers being of opposed eccentricity in the end and intermediate cylinders 5 and 6, respectively; and nearly surrounding said working chamber 15 is an exhaust passage 16. In the case of the central cylinder 6, the exhaust passage 16 communicates through an open port 17 with a central exhaust chamber 18 that is tapped by a main exhaust pipe 19 leading to the atmosphere or to a condenser, Where the latter is employed. In the case of the end cylinders 5, the exhaust passage 16 communicates through vertical and

horizontal extensions

20 and 21, respectively, with the central exhaust chamber 18.

On the upper side of the central cylinder 6 is a steam chest 22 having twin compartments 23 and24 from which

inlet ports

25 and 26 lead into the working chamber 15 of 22 is a valve casing 27 containing a rock valve 28 and supplied with steam through a supply pipe '29. The valve casing 27 is supplied with two

inlet ports

30 and 31 that communicate with

ports

32 and 33 in the top wall of the steam chest 22; and the rock Valve 28 is hollow and is provided with a radial port 34: adapted to register with either of the ports 30' and 31 to facilitate exhaust from one of the compartments of the steam chest While the other compartment is being supplied with live steam which enters around the rock valve 28.

Precisely the same steam supply mechanism is employed on each of the end cylinders 5, the only difierence being that this steam supply mechanism is located on the lower side of the cylinder instead of on the upper side; and to shorten the description I have identified the parts of this steam supply mechanism on the end cylinder in Fig. 4: with the same reference numerals that are employed to identify corresponding parts in Fig. 3; it being understood that the three supply pipes 29 are connected to a common source of live steam supply.

Through the circular wall of each working chamber 15 are formed a series of spaced valve seats 35 and 35 that are normally closed by puppet valves 36 and 36 respectively. The stems 37 and 37 of these valves extend through openings 38 and 38 in the outer wall of the exhaust passage 16 and also through

valve cages

39 and 39 secured to said outer walls and are further provided with disk valves 40 and 4:0 normally closing the openings 38 and 38 under the influence of

light springs

41 and 41 in said valve cages. The valve cages 39 are connected with each other and with the compartment 23 of the steam chest by a line of piping designated by 42; and the corresponding series of valve cages 39 are connected together and to the compartment Qt of the steam chest by a line of piping designated by 42. The circular wall of the working chamber 15 of the intermediate cylinder 6 is provided with an open exhaust port 43 leading into the exhaust passage 16 at a point diametrically opposite the central partition of the steam chest 22; and the circular Wall of the working chamber of each end cylinder 5 is provided with a similar exhaust port 43 similarly located relatively to its steam chest.

Formed integral with the end walls 10 of the housing are inwardly extending bearing bosses 14k that are eccentrically bored to ac commodate the driven shaft 1 and form a running fit with the cast iron lining 2 of the shaft 1. Accurately fitted and secured to the inner ends of the bearing bosses 4A are a. pair of intermediate bearing bosses 45 also eccentrically bored to accommodate the shaft 1 and of opposed eccentricity relative to the bearing bosses 14. These intermediate bearing bosses 45 may be centered by dowels 44 on the inner ends of the bosses 44 entering corresponding recesses in the outer ends of the bosses 45, and strongly secured in place by long screws 46 passed through the outer bosses 44 and into the intermediate bosses 45. Both sets of bearing bosses are, of course, of cast iron, and the cast iron lining 2 of the shaft 1 engages all of said bosses with a running fit. This construction I regard as of primary importance for the reasons that cast iron runs better on cast iron under heat than any other metals or combinations of metals, and by reason of the running fit of the shaft in the hubs or bearing bosses, said shaft affords a strong support for the latter, maintaining their perfect alinement, and thereby insuring the true and accurate run ning of the piston vanes or blades in their respective cylinders.

lVithin the several cylinders is a built-up piston drum that comprises the following parts: 47 (Fig. 3) designates a central drum section that occupies the working chamber of the intermediate cylinder 6, and suitably doweled to the ends of this central drum section 47 are a pair of end disks 48, integral with which are the drum sections 49 (Fig. 4) that occupy the working chambers of the end cylinders 5. Doweled on the outer ends of the drum sections 49 are outer end disks 50, and these latter, end drum sections 49, the intermediate disks 48 and the central drum sections 47 may all be strongly secured together by long screws or tie-bolts indicated at 51 in Figs. 1, 2 and 3. Centrally of the intermediate drum section 47 is an integral internal web 52 that, as best shown in Fig. 5, is strongly secured to the large central hub 3 of the driven shaft as by keys 53, this central web and hub forming the sole connection of the built-up piston drum to the driven shaft. The outer portions of the drum disks 48 form steam-tight bearings with the outer sides of the side walls of the cylinders 5 and 6 through the agency of cast iron packing rings 54, as shown in detail in Fig. 12, from which it will be seen that each packing ring is a split ring chan neled on its wearing face to provide a pair of practically knife edge bearings 55, the ring being ported from front to rear be tween said bearings as shown at 56 to equalize the pressure of the leakage on both sides thereof. Each packing ring is set in a groove 57 formed in the outer face of the cylinder wall, and is backed by a spiral spring 58 laid in said groove behind the packing ring and lightly forcing edges 55 of the latter against the face of the disk 48. Similar packing rings are employed to pack the inner faces of the end disks 50, as clearly shown in Fig. 2.

Within each of the outer cylinders 5 is a group of radial piston blades or vanes. 59,

herein shown as 8. A group of these piston vanes is shown in detail in Fig. 6 from which it will be seen that the several vanes are provided with annular or ring-like shanks or stems 59 that embrace the stationary eccentric bearing bosses 44, preferably through the intermediary of hardened bushings 60 fitted to the latter, and said annular shanks 59 are so spaced on the several vanes that they may be assembled in a closely internested manner as illustrated in the sectional view of Fig. 2. A similar group of piston vanes occupies each half of the intermediate cylinder 6, being mounted in a similar fashion on bushings 61 fitted to the eccentric bearing bosses 45. Corresponding vanes of the two series which occupy the intermediate cylinder occupy the same planes and their adjacent radial edges abut against each other, so that each pair has the effect of a single broad vane, which latter might be employed did not structural and assembling difiiculties make it impracticable. To accommodate and provide clearance for the meeting edges of these vanes, the central internal ring or flange 52 of the central drum section is radially slotted, as shown at 62 in Fig. 5.

The outer edges of the piston vanes are suitably packed to form steam-tight joints with the circular wall of the working chamber, such packing as herein shown comprising cast iron strips 63 of T-form in cross section, fitted to grooves in the edges of the vanes and forced outwardly into wiping contact with the circular wall of the cylinder by coil springs 64 laid in the bottoms of the grooves. Similar packing strips are employed in the side edges of the piston vanes, with the exception of the contiguous side edges of the two sets of piston vanes which occupy the intermediate cylinder 6, where, since no sliding contact exists be tween said contiguous edges, packing is unnecessary.

The cylindrical piston drum 47 and 49 are formed at uniformly spaced intervals with circular bearing seats 65, in which are mounted a series of suitably packed swivelbearing members or rockers designated as an entirety by 66, through which the piston vanes slide during their rotation around the axis of the cylinder. In Figs. 7 to 11 inclusive, I have illustrated a practical specific construction of such rocker or swivel-bearing member, which, for purposes of assembling with the form of piston vanes shown, requires to be made in sections. Referring to said figures, 67 designates each of two main body pieces of segment form in cross section that are provided with a series of grooves 68 in their outer curved faces to receive packing strips 69 and with another series of parallel grooves 70 on their inner or flat faces to receive packing strips 71. The two body members 67 are united at their ends by circular end blocks 72, each of which is provided on its inner face with a tongue 73 of suitable width to form a spacing block for the body members 67 so as to provide a slot 74 (Fig. 8) of suitable dimensions to fit the body of the piston vane or blade. The inner faces of the tongue 73 are transversely grooved as shown at 75 (Fig, 10), and said grooves are fitted with packing strips 76 designed to engage the side edges of the piston vanes. As shown in Fig. 11, the longitudinal and transverse packing strips 71 and 7 6 may conveniently be made integral, the longitudinal strips 71 in one of the body members 67 having angular extensions 76 to pack the grooves in one of the end pieces, and the longitudinal packing strips 71 in the other body member 67 having integral angular extensions 76 to pack the grooves in the other end piece. The body members 67 are further provided with circular transverse grooves 77 (Fig.

8) near their ends to receive packing rings 78, and the end pieces 72 are formed with similar transverse grooves 77 that, when the end pieces are in place, register with the transverse grooves 77 and are occupied by the packing rings 78. The external packing strips 69 are notched near their ends in line with the transverse grooves 77 so as to interlock with the packing rings 78. The end pieces are equipped with additional packing rings 80 and are secured to the ends of the body members 67 by screws 81, and the body members and end pieces are further bonded together by cross pins 82 passed through the ends of the body members and the tongues 73 of the end pieces.

From the foregoing, it will be seen that the rockers thus form a steam-tight joint with both their seats in the piston drum and also with the piston vanes that pass through them. As the side edges of the piston vanes have sliding and oscillating engagement with the faces of the

end disks

48 and 50 of the drums, the rockers or swivel members 66 are so mounted that their end pieces are fitted into circular sockets 83 in the faces of the

disks

48 and 50, as clearly shown in Fig. 2; it here being noted that in' case of the intermediate cylinder 6, it is practicable to employ long swivels accommodating both sets of piston vanes that occupy the intermediate cylinder.

The steamsupply valves of the several cylinders are connected up so as to be simultaneously actuated in the same direction from a single starting, stopping and re-.-

versing lever, this mechanism being shown in Figs. 1 and 2, whereln 1t Wlll be seen that the rock valve 28 of the central cylinder is formed with a shaft-like extens1on84, on'

the outer ends of which are crank arms 85 that are connected by links 86 with simllar crank arms 87 on the stems of the rock valves of the end cylinders. Fast on the stem of the rock valve of the intermediate cylinder is a crank arm 88 similar to and parallel with the crank arms 85,. the outer end ofwhich has a pin and slotconnection with a hand lever 89 that is pivoted at 90 on a bracket 91 secured to the steam chest 22 of the intermediate cylinder. hand lever 89 is in the full-line position shown in Fig. 1, the rock valves 28 of the intermediate and end cylinders occupy the positions shown in Figs. 3 and t and the piston drums and driven shaft rotate in a direction indicated by the arrows in the latter figures. When the hand lever 89 is in, an intermediate or horizontal position, both

ports

30 and 31 are blanked, and the engine is without steam. When the hand lever 89 is shifted to the dotted-line position of Fig. 1, the rock valves 28 will admit steam to the ports 31, thus reversing the direction of rotation of the piston drums and driven shaft. As shown in the drawings the rock valves 28 are made hollow and are provided with the radial port 35% so as to permit a free discharge of a portion of the compressed exhaust, if desired, the bore of the central valve 28 communicating with the atmosphere through one of the valve stem extensions 84, which is made tubular, as indicated in Fig. 2, and the bores of the rock valves of the end cylinders communicating with the atmosphere through hollow bearing members or stems as indicated in Fig. 2.

The

several steam pipes

42 and 42 are equipped with cut-off valves 92 and 92 at points just outside the steam chests 22 for the purpose of cutting out or rendering idle the pipe on the idle side of the cylinder. These valves may, of course, if desired, be suitably connected up to the hand lever 89 so as to be operated by the latter simultaneously with the operation of the rock valves 28.

In operation, assuming that the parts are in the relative position shown in Figs. 3'

and 4, live steam enters the working chambers of the cylinders through the ports 25, driving the piston drums and vanes in the direction indicated by the arrow. .As each piston vane sweeps past the open exhaust port &3, the body of steam between'it and the next succeeding. vane is reduced to atmospheric pressure by reason of exhausting through the port 43 and the exhaust ports and ducts which lead it into the central exhaust chamber 18 and thence through ex haust main 19 to the atmosphere or condenser. During this time the valves 92 are open and the valves 92 closed so that a portion of the live steam in the compartment 23 of the steam chest fills the valve cages 39 and counteracts the live steam pressure on the faces of the puppet valves 36, thus holding the latter closed. After each piston vane passes the exhaust port e3, compression of the steam trapped between said vane and the next forward vane begins to take place owing to the gradual contraction of its volume, and this compression is relieved through the puppet valves 36 which open and admit the flow of-most of this steam to the exhaust conduit 16 and thence to the final exhaust. The relatively small amount of compression occurring beyond the last of the three valves 36 is vented through port 26, compartment 24,

ports

33, 31 and 3e and the bore of the rock valve 28 and its hollow stem to the atmosphere; the valve 92 being at this time closed so as to prevent interference with the free opening of the val e 36 through pressure accumulating in the compartment 24.

When the engine is reversed, the described operations occur on the opposite or reverse sides of the several cylinders, the valves 92 being closed, and the valves 92' opened, so

that the valves 36 are held closed by live steam pressure in the valve cages 39, and the valves 36 open freely to relieve the compression.

From the foregoing description it will be apparent how the several stated objects of the invention are accomplished in the con struction shown and described. As the engine shaft has a running fit within and through all the eccentric bearing bosses of the piston vanes from endto end of the housing, said bearing bosses are strongly supported against any bending or yielding movement, thus causing the piston vanes and drums to rotate in true and accurate relation to the stationary parts with which they cooperate, reducing friction and wear, and making the engine more perfectly steam tight and reducing the stuiiing boxes required practically to the twopacking glands 14 for the driven shaft in the opposite ends of the housing or casing. By lining the steel shaft with a metal (such as cast iron) that is the same as the metal of the hearings in which it runs, irregularities due to inequalities of expansion under heat are eliminated and both undue friction and undue looseness of fit are avoided. The relative arrangement of cylinders,-two narmachining of the intermediate drum section. All the packings shown and described, with the exception of the end shaft packings, are of cast iron, thus making the packing feature of the engine very simple and inexpensive. The employment of a single wide intermediate cylinder, instead of a pair of intermediate cylinders, has manufacturing advantages and reduces the number of cylinder ring packings and piston vane packings required as well as the number of swivel bearings and end disks for the drum sections. It may here be noted that the end walls 10 of the engine housing are internally ribbed as shown at 93 in Fig. 2 for purposes of strength, said ribs occupying otherwise unused space permitting a smooth exterior to the end walls. Suitable provisions are, of course, made for supplying a lubricant to the bearings of the driven shaft and the bearing rings of the piston vanes; but as such oiling system forms no part of the present invention the same is not herein shown and described. It will be noted, however, that the cylinder ring packings. and piston vane packings are of such character that they will be adequately lubricated by means of condensed steam without requiring the application of an oil lubricant.

Without, limitingv myself to precise details,

of construction herein shown and described but reserving such modifications and variations as would fall within the scope of the following claims I claim:

1. In an engine of the type described, the combination of a housing containing a cylindrical working chamber, a stationary cast iron bearing boss in said working chamber, a steel drive-n shaft extending eccentrically through said bearing boss, said shaft having a cast iron lining engaging said bearing boss with a running fit, a slotted piston drum in said working chamber having a web connection to the lining of said shaft, and a plurality of piston vanes iournaled on said bearing boss and extending through the slots of said drum and having wiping contact with the walls of said working chamber.

2. In an engine of the type described, the combination of a housing containing a plurality of cylindrical working chambers arranged side by side and having end walls provided with inwardly extending-cast iron bearing bosses. a steel shaft extending eccen- 12 trically through said bearing bosses and end walls, said shaft having a cast iron lining engaging said bearing bosses with a running (it, a slotted sectional piston drum occupving said working chambers and having a single central web secured to the lining of said shaft, a plurality of disks secured to and between the ends of the sections of said drum and forming rotating side walls of said Working hamber and pi ton v n i naled on said bearing bosses and extending through the slots of said drum and having wiping contact with the walls ofsaid work- .ing chambers.

3. In an engine of the type described, the

combination of a housing containing three cylindrical working chambers arranged side by side and having end walls provided with cast iron bearing bosses each comprising a portion integral with its end wall and extending through an end working chamber and a portion attached to the inner end vof said integral portion and vextending approximately to the center of the intermediate working chamber, the portions of said bearlngbosses n sald endchambers belng diametrically eccentric to the portions thereof in said intermediate chamber, a steel driven shaft extending eccentrically through all said bearing bosses and said end walls, said shaft having a cast iron lining engaging said bearing bosses .with a running fit and a central integral hub member lying between the combination of a housing containing three cylindrical workin chambers arranged side by side, the two outer working chambers being each one-half the width of the intermediate working chamber and diametrically eccentric to the latter, end walls on said housing provided with cast ironirbearing bosses each extending through an end working chamber and approximately to the center of the intermediate working chamber, the portions of said bearing bosses 'within the several chambers being axially concentrio with the latter, respectively, a steel driven shaft extending eccentrically through all saldbearing bosses and said end-walls, sa1d shaft havlng a cast 1ron l1n1ng engag ing said bearing bosses with a running fit and a central hub member integral with said lining and lying between the inner ends of of said bearing bosses, a slotted sectional piston drum occupying'said working cham bersand having a single central web -secured to said hub member, a plurality of disks secured to and between the ends of the 7 sections of said drums and forming rotating s1de walls of sald worklng chambers and piston vanes journaled on said bearing bosses and extending through thev slotsvof said drum and having wiping contact with the walls of said working chambers, I

5. In an engine of the type described, the combination of a housing containing a cylindrical working chamber, end Walls on said housing each having a bearing boss extending inwardly of said working chamber to approximately the center of the latter, a driven shaft extending eccentrically through said bearing bosses, a slotted piston drum in said working chamber having a central web connection to said shaft, that is radially slotted to afi'ord piston vane clearance and two sets of piston vanes journaled on said bearing bosses, respectively, and extending through the slots of said drum, the proximate edges of the vanes of the two sets lying within the radial slots of said web connection and abutting against each other.

6. In an engine of the type described, the combination of a housing containing a cylindrical working chamber, end walls on said housing each having a cast iron bearing boss extending inwardly of said working chamber to approximately the center of the latter, a steel driven shaft extending eccentrlcally' through sald bearing bosses, said shaft havlng a cast iron lining forming a runing fit in said bearing bosses and a central hub member integral with said lining 'and'lying between the inner'ends of said bosses, a slotted piston drum in said working chamber having a central web connection to said hub member that is radially slotted to afford piston vane clearance and twosets of pistonvanes journaled on said bearing bosses, respectively, and extending through the slots of said drums, the proximate edges of the vanes of the two sets lying within the radial slots of said web connection and abutting against each other. I

7. In anengine of the type-described, the combination of'a housing containing a cylindrical working chamber, a steam supply valve admitting steam. to said working chamber, an exhaust conduit in said housing partiallysurrounding said working chamber,"an exhaust port connectingsaid work ing' chamber with said exhaust conduit a point diametrically oppositesaidsupply valve, a driven shaftextending eccentrically through said working chamber, a bearing boss ,in which 'said'shaft' is journaled located within and concentric with said working 7 chamber, a rotary piston'drum concentric with and secured to'said shaft, a series of piston vanes journaled onsaid bearing-boss and swiveled in and extending through said drum, and a group of'compression relief valves located at spaced intervals in one side of the-cylindrical wall of said working chamber between said exhaust port and said steam supply valve. 1

8. In an engine of the type described, the combination of a housing containing a cylindrical working chamber, a twin compartment steam chest ported to said working chamber, a steam supply valve adapted to admit steam to either compartment of said chest, an exhaust conduit in said housing ex tending from one side of said steam chest around said working chamber to the other side of said steam chest, an exhaust port located opposite said steam chest and afiording communication between said working chamber and said exhaust conduit, a driven shaft extending eccentrically through said working chamber, a bearing boss in which said shaft is journaled located within and concentric with said working chamber, a rotary piston drum concentric with and secured to said shaft, a series of piston vanes journaled on said bearing boss and swiveled in and extending through said drum, a group of compression relief valves located at spaced interval in the cylindrical wall of said working chamber, and means for holding closed certain of said compression relief valves that are located on the working side of said chamber.

9. In an engine of the type described, the combination of a housing containing a cylindrical working chamber, a twin compartment steam chest ported to said working chamber, a steam supply valve adapted to admit steam to either compartment of said chest, an exhaust conduit in said housing extending from one side of said steam chest around said working chamber to the other side of said steam chest, an exhaust port in the cylindrical wall of said working chamber located opposite said steam chest and affording communication between said working chamber and said exhaust conduit, a driven shaft extending eccentrically through said working chamber, a bearing boss in which said shaft is journaled located within and concentric with said working chamber, a rotary piston drum concentric with and secured to said shaft, a series of piston vanes journaled on said bearing boss and swiveled in and extending through said drum, a group of compression relief ports located at spaced intervals in the cylindrical Wall of said working chamber and connecting the latter with said exhaust conduit, spring-actuated valves normally closing said compression relief ports, and steam-actuated means for holding closed certain of said relief valves that are located on the workin side of said chamber.

10. In a multiple cylinder engine of the eccentric piston type, the combination of a housing containing end working chambers of like eccentricity and an intermediate working chamber of diametrically opposite eccentricity, a driven shaft extending through said working chambers, piston drums and vanes in said working chambers operatively connected to said driven shaft, a steam supply valve on the upper side of said intermediate working chamber, steam supply valves on the under sides of said end working chambers, a central exhaust chamber located beneath said intermediate working chamber and communicating with the exhausts of all three working chambers, and means for simultaneously actuating the several supply valves from a single lever.

11. In an engine of the type described, the combination with a piston drum formed with a circular longitudinal bearing seat, and a piston vane, of a bearing member for said vane swiveled in said bearing seat and comprising a pair of segment-shaped body members, a pair of circular end members uniting and spacing the ends of said body members, external packing strips in the outer sides of said body members to engage said bearing seat and internal packing strips in the inner opposed faces of said body members to engage said vanes.

12. In an engine of the type described, the combination with a piston drum formed with a circular longitudinal bearing seat, and a piston vane, of a bearing member for said vane swiveled in said bearing seat and comprising a pair of segment shaped body members, a pair of circular end members having inwardly extending tongues lying between and spacing the ends of said body members and secured to the latter, external packing strips in the outer sides of said body members to engage said bearing seat, and internal packing strips in the inner opposed faces of said body members and tongues to engage the sides and edges of said vanes.

13. In an engine of the type described, the combination with a piston drum formed with a circular longitudinal bearing seat, end walls on said drum having circular sockets registering with the ends of said bearing seat, and a piston vane, of a longitudinally slotted bearing member for said vane swiveled in said bearing seat and sockets, said bearing member being provided with packing strips engaging said bearing seat and the sides and edges of said vane and with packing rings on its ends engaging said sockets.

JOHN D. CARROLL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. c."