US2498971A - Piston and cylinder assembly - Google Patents

Description

5 Sheet-Sh'eet 1 F. F. WARNER E'l'AL PISTON AND CYLINDER ASSEMBLY Feb. 2s, 195o Filed Jan. 29. 1944 Feb. 28, 1950 F. F, WARNER Erm. 2,498,971

PISTON AND CYLINDER ASSEMBLY Filed Jan. 29, 1944 i 3 Sheets-Sheet 2 ATTORNEY Feb. 2s, 195o F, F, WARNER AL 2,498,911

PISTON AND CYLINDER ASSEMBLYl Filed Jan. 29, 1944 l 3 Sheets-Sheet 5 far f A INVENTORS; A omega-173:; la@ CHM n FLOYD l- WARNER MAR# L; @Roo/f6 fwn Ju U5 BARDELME/ER Patented Feb. 28, 1950 PISTON AND CYLINDER ASSEMBLY Floyd F. Warner, Mark L. Brooks, and Julius E. Bardelmeier, St.`Louis, Mo.

Application January 29, 1944, Serial No. 520,354

Claims.

This invention relates to improvements in cylinder and piston assemblies, and more particularly to improved construction, assembly, and method of operation of a piston, a cylinder in which the piston operates, and one or more abutment elements serving to seal the end zones of, or constitute a partition across the cylinder.

Expressed somewhat more concretely, an important object of the invention is attained in an assembly of cylinder, piston and gate or abutment, through which the piston passes with no appreciable loss of uid from the cylinder of or in which the gate abutment constitutes a closure.

A further important object of the invention is attained in an assembly of the type referred to in the preceding object, and in which a gate type abutment may be primarily operated by the piston incident to traversal of the abutment thereby.

An additional object of the invention is attained in the provision of a substantially co'ntinuous running seal between a gate type abutment and a piston operating through such abutment.

The foregoing and numerous other objects will more clearly appear from the following detailed description of a presently preferred embodiment of the invention, considered in connection with the accompanying drawing. Since it is to be understood that numerous variations may be made in valving provisions, details of cylinder and valve construction and arrangement, and means for lubrication of the various moving parts, the present description and claims are conned to those structural features of the invention having to do with the piston, cylinder and abutment features.

In the drawings:

Fig. 1 is a half sectional view taken in a plane including the axis of rotation of certain of the rotary elements and a center power shaft;

Fig. 2 is a sectional elevation taken in a plane normal to the axis of rotation and medially of a rotor and one of the cylinders or units of the assembly;

Figs. 3, 4, 5, 6 and 'l are diagrammatic illustrations showing, as based on the general structural arrangement of Fig. 2, but omitting details, different positions of two pistons each traversing a pair of cylinder chambers, and illustrating one mode of application of present principles to they operation of a rotary-piston type of internal combustion engine;

Fig. 8 is a diagrammatic illustration of an abutment gate-actuating cam profile, developed in a single plane for a better understanding of opening and closing movements of the one or more abutment gates;

Fig. 9 is a top or plan View of a preferred form of piston, and

Figs. 10A, 10B, 10C, 10D, 10E and 10F represent a series of gate port openings successively attained as the abutment gate is moved from fully closed, to fully open position to permit passage of one of the pistons therethrough, this series of figures, diagrammatic in nature, similarly representing successive cross sectional contours of the leading or camming portion of one of the pistons, the locations of corresponding sections being indicated by lines AA, B-B, CAC, D-D, E-E, and F-F in Fig. 9.

Referring now by characters of reference to the drawing, and rst to Figs. 2 through'7, two` pistons are respectively numbered I and 2, the

more detail. These pistons both operate in a true circular path, and within one of a plurality of annular, or more particularly, toroidal cylinders 3.

Referring now to Fig. 1, the assembly may include a casing I0 provided with suitable shaft bearing portions II in which is operable a power shaft I2. This may, for reasons not material to the present disclosure, be of hollow form as shown. Secured to the shaft I2 against angular displacement thereon, are shown a pair of rotors I3 and I4, each characterized by a hub portion I5 which may be keyed or otherwise secured (by means not shown) to the shaft I2. portions of rotors I3 and I4 serve peripherally to carry the pistons I and 2, for which purpose, at diametrally opposite positions on each rotor web, there is provided a piston-mounting projection I6 apertured to receive a piston pin I'I, this mounting being preferably but not necessarily in the nature of a pivotal mounting.

Just inwardly of its periphery each of the rotors I3--I4 is provided with a pair of annular projections 2IJ. As will readily appear from Fig. 1, each such projection interts'a corresponding annular recess 2I of angulate section, formed in a sealing ring element 22, there being a pair of the rings 22 disposed oppositely to each other on opposite sides of each rotor periphery, and the rings 22 being retained in and supported by an annular ring-pocket block 23. The lower wall of the block 23 is slotted as at 24 to permit operation in the slot, of -the web of the adjacent rotor. The rings 23 coact with projections 20 in sealing relation either by resilience of the ring elements, or if desired, by biasing effect of abody of fluid The web kept under hydraulic pressure, lbehind one or both of the rings. For this purpose there is shown a space 25 between at least one of the rings, and the adjacent wall of the element 23. The ring retainer block structure is preferably supported by and secured to an annular block which, although obscured in Fig. 1 by certain of the abutment elements, consists preferably of a casting or like body in which are formed the toroidal cylinders. It will have appeared that, from-the provision of the sealing rings 22, coacting with the extreme peripheral portions of the rotors I3 and I4, such peripheral portions are provided with a running seal over their full perimeters, thus preventing escape in a radial inward .direction of the various fluid contents of the cylinders 3 such as otherwise might occur `where the pistoncarrying projections or brackets I6 extend into the cylinders. Depending upon the desired application and service requirements of the asn sembly, any practical plurality'of the cylinders 3, each containing operatively, one or more of thepistons I and 2, may be arranged in axial adjacence; it is now obvious that, if` desired, one or `more lcylinders of this general type maybe employed .sayv as the cylinders ofanzengine of rotary piston type, while one or more additional such cylinders maybe employed as pumps,:com pressors, superchargers and as operating accessoriesto the enginexproper, considered as a prime mover. The description will, for brevity, be directed to a compressor piston, operable in a toroidal cylinder.

Anv annular cylinderfor assembly thereof may be provided in diametrally opposite zones eX- teriorly of the cylinder proper, with a. manifold or reservoir structure-.two of whichare shown irl-Fig. 2,:and sincel these are or may, be, identical, although reversed in gposition,-a description of one will suffice for both. In thisconstruction a cell or 'chamber 30 is formed within anvelement 3I provided -with external cooling ns or ribs .32, provided also with a, tapped aperture 33 for the receptionfof a gauge or other accessory and-With a pair of substantially. cylindrical or even preferably-tapered lcylindrical valve seats,-134 and 35, for the operative'reception respectively, ofk rotary valves 36 and31. Each ofthe valves -contains a transverse fluidy passage 38, and the Istructure justdescrbed maybe conveniently mounted-on the cylinder block structure,as bybolts or screws 4U. Although-it maybe noted as preferable'to actuate the valves-36 and 31 withra quick Oscillating motion, andto operate valve 31 entirely afterfull opening and full closing of valve YI-, the specic, preferred means of lvalve actuation beingthelsubject of a contemplatedl application for patent-on this feature per se, need not. be further described` herein.

It is a preference to utilize the described pair of pistons I and 2 operating continuously in1such manner that. each fully traverses the lentire an nular space or two `half-annular chambers,v of each'cylinder. With this'arrangement there is preferably provided azpair of abutments'generally indicatedin Fig. 2 at 45 and 46. In-preferred form each abutment 'consists of a reciprocally actuated, slidably movable gate, the gate element proper of which is indicated at 41 (Fig. 1) and which is arranged to reciprocateV from thepositionshown by dotted lines in Fig. 1, downwardly in. that figurev to the full-open position=shown by full lines but iny section.

.As will-appear, actuation .of each of the gates 41 iseffected` primarilyby the pistons in passing therethrough, although for the purpose of initiating the movement of the gate barely in advance of each piston reaching the gate, there is preferably employed a cam arrangement (later described) serving to eifect the movement of element 41 downwardly (Fig. l), return thereof to its initial or closed position being effected by a gate return spring or plurality thereof 50, provided with an enclosing housing 5I of cylindrical form, this housing being in turn reciprocally movable within a stationary holder 52. A plural- `ity of the spring and housing assemblies may, if desired be employed for each gate.

As a means tending to bias the lower margin :53 of the gate, into close sealing engagement with Vthe upper margins of the sealing rings 22, and Vsimilarly with the upper margins of the ring carriers 23, there are utilized a plurality of coil fspringsl which are kept under some moderate loading between the innermost margins of the elements .3I ,and the upper or outer margin 55 of the slidable-.gate member 41.

Proceeding nowto a description of the gateactuating cam means, a preferred embodiment thereof includesa plate or disc generally indi cated at 60, which is carried by and securely assembled to the shaft I2 as by a key or any other lsuitable locking means (not shown) so that the camv plate operates in assured and fixed timed relation vwith the rotors such as i3 and I4, and

hence in a definitely timed relation to the pistons.

-Mounted so as to project substantially at a rightangle to the disc 6U, is a cam element 5I. Forreasons of effecting a precision adjustment of the cam 6I with respect to the disc SEI, the canris preferably formed as a separate element andA secured to the `disc as by a plurality of screws, of which one is shown at 62. The screw-receiving apertures in plate 6U may, if desired, be somewhat enlarged to'permit some moderate degree of'angular adjustment of the cam 6I with respect to cam plate Ell. It will have appeared that the movable gateelement proper 41 of the abutment assembly, is somewhat undercut in the region of its innermost right hand margin as indicated at 63, whereby portion B3 serves, in effect, as a follower for cam 6I. It will be understood that, although a single cam assembly is described, '1 the requisite plurality, corresponding tognumber of gate elements, will be utilized.

A preferred design of profile of cam 6I will hereinafter be more particularly described, since it will be better understood following a discusw sion of the structure of pistons I and 2. As heretofore noted, the pistons constitute, by preference, the primary gate-actuating agencies, and in effect themselves serve as `gate-operating cams so'as to supplement the operating inuence of cam 6I, all as will later more clearly appear.

It will have been noted from Fig. 1 that the gate 41 is ported to enable passage through the gate, of the several pistons in each of the cylinders 3 controlled by the given abutment gate. These ports are indicated in dotted lines at te (Fig. l), and by preference, are circular and each of an area ycorresponding to the transverse sectional areas of each of the cylinders 3. It will now have become obvious that, as the gate element 41 is slidably shifted in an opening direction (Fig. 1), an initial effect will be to create a very minor, merely pin-hole opening adjacent the-side wall of each cylinder. This opening is of a shape approximating that of the overlapping area ofztwopartly superposed circular elements.

and the extent or area of such opening will be increased until it becomes fully circular. This occurs when the gate reaches full-open position, and itsA circular port becomes fully coincident with the cross section of the cylinder. Closing movement of the gate will obviously result in a reverse sequence of openings of gradually reducing area until nearly or completely full closure of the gate takes place. A diagrammatic showing of the forms of six such successively attained piston-openings in the gate, will be seen in Fig. A and those following, it being noted that these correspond closely to successive sectional shapes of the fore end or nose of the piston, hereinafter described.

Proceeding now to a description of the pistons I and 2, each thereof, as will appear from Figs; 2 and 9, is of what may be termed a horn shape; since the shaping and construction of the two pistons may be identical, a description of piston I will suce for both. Each piston is preferably formed on a longitudinal axis which is arcuate, or substantially so, the arc thereof being drawn on a center which `approximates the axis of rotation of the rotor I3 or I4 by which the piston is carried. The rearmost or trailing one-third or so of the piston, indicated generally at 10, is or may be close to cylindrical form, departing from a true cylindrical form only by reason of being formed on an arcuate longitudinal axis. The leading two-thirds or so, being the nose of the piston, indicated at 1I, is characterizedby an apex portion 12, and is of a gradually increasing cross section rearwardly of the apex back to the trailing portion 1li. Successive cross sections of piston portion 1I may be described as derived from successively larger overlapped areas of two circles each of the same diameter as the cylinder bore, the successively larger cross sections corresponding to the superposed parts as such circles are successively brought into increasingly overlapped relation. From the description just given, and from Figs. 10A, 10B, 10C, 10D, 10E and 10F, it will appear that the top and bottom of leading portion 1I are each drawn somewhat to an edge, and that the opposite lateral surfaces of leading piston portion 'II are each formed substantially on a true arc, but with the centers of such arcs distinctly out of coincidence.

It should further be noted that, in the example disclosed, apex 12 is neither located in nor travels along a median of the cylinder, but lies close to the side thereof identified with the iirst opening of the gate element 41. From this fact results the skewed or canted aspect of the piston when viewed in plan, as will appear from Fig. 9.

It is a preference not to attempt any packing provisions for the leading portion 1I of the piston, but is a distinct preference to provide the trailing portion 10 with a series of ring grooves, each for the reception of a piston ring or like packing element 13.

While for simplicity of abutment structure each abutment is shown as utilizing but a single reciprocable, ported gate element, it should be noted that the gate shown may be duplicated in each abutment assembly, with the two gates in adjacence, each provided with an individual camming assembly and with the ports of the two gate elements arranged to approach, first partly overlap, then be brought into register to pass the piston. Although requiring twice the number of gates otherwise necessary, and additional cams, an advantage is presented by the double gate arrangement in that the apex of the piston may Ail) be disposed centrally thereof, with some simplication of piston production, and the gate opening thus initiated in a region in or near the axis of the cylinder. i

The operations of cam 6I and of piston I, for example in effecting an opening movement of the gate element 41, are thought to have been made apparent from the description of parts and their relation, but it may be noted for completeness, as a preference, to initiate the opening movement of the gate slightly in advance (say only one or two degrees) of-actual attainment of gate position by the apex 12 .of the piston. This effect is, now obviously, attained by precision timing of cam 5I, such that the gate will have barely opened no more than to provide a suilicient starting aperture for entrance of the apex 12 of the piston. This eifect, attained by cam prole, will best be seen from the diagram of Fig. 8 wherein there is shown as a planar development, the leading margin of the cam lobe and indicated at 80, a toe portion which serves to effect such an initial gate opening. At this point the piston takes over the gate opening movement, and thereafter, and until the piston has completely passed through the port of the gate, the piston serves as the gate-actuating agency in conjunction with the cam, with the now obvious advantage that there is thus assured a running seal between the margin of the port '65 in the gate, and the periphery of the piston portions 1I and 10 in this sequence. It may be desirable, although not in all cases strictly necesn sary, that the margins of the ports '65 of the gate be somewhat iiared or tapered to enhance the.

area of wiping engagement of the gate port mar gins with the periphery of the piston portion 1l. It will now be observed from the cam profile of Fig, 8, that, as soon as the piston has attained such a position that its trailing portion of circular section reaches the port 65 of the gate, no further gate opening takes place, but that the piston remains nonetheless closely embraced by the port margin and adjacent coacting portion of the cylinder wall, so as to perfect the fluid seal in this end zone of the cylinder. A further study of the cam prole of Fig. 8 will reveal a further desirable feature namely, the provision of the gradual downward trailing slope indicated at 8l of the camming contour of the cam lobe.

It should here be noted that, during cam movement such that the gate is actuated by the toe of the cam lobe, and again during that portionk in which the heel of the lobe shown at 8|, is engaged by the gate under the inuence of spring 50, the gate is entirely carnecontrolled by member 6I, but that, during all intervening time being through the angle shown as 671/2 degrees in Fig. 8, the gate is primarily or solely under control of the piston. Although a cam contour is provided between portions 80 and 8I such as to effect substantially the same gate opening movement as results from the piston, the cam profile or lobe nevertheless bears a slightly trailing relation, or otherwise expressed, a slightly spaced relation, with respect to the cam following portion 63 of the gate.

In the showing of Fig. l, embodying two axially aligned cylinders, they may be employed for differing purposes, or both as compressor cylinders, acting separately or as successive stages. Where only two cylinders are employed in adjacence, the disclosed arrangement can best be timed within itself and balanced -by angularly displacing the pistons within one cylinder,

menaant degrees i from:correspondingggpistonsfiof l`thef-.companioni cylinder', inzwlflichfcase4 the abutment assemblies iincluding the Ygates; will `obviously be 90v degrees displaced in the two cylinders; thus requiring aH separate cam plate,.cams, etc., with gates individual tothe associatedcylinder, but

without departing from the majorelements and features described.Y

When it is considered that under" certain conditions-at'v least :one Ioi the pistons is subject to a'maximumV uid pressuresubstantially at thel timewhenit musttraversethe gate, the advantage, now evident, of beingl ableto -fmaintain they end'of the cylinder.substantiallycompletelysealed while permitting passage of' the pistonftherebeyond; cannot be over-estimated.l Thisadvantage-particularly evident in and most importantly adapted .to .a rotating piston type of'structure 'in distinction from the so-calledoscillating piston types of compressor.

The operation of the present structureis best seen by reference to a simplified 4construction in which is utilized only a single cell or: chamber such as 3D, for example,l the Vone at theleft'hand side'of Fig. 2. Such'chamberis equipped with a self-opening, spring-loadedintake valve (not shown), opening inwardly of chamber 30', and an outwardly opening spring-loaded discharge valve (not shown) controlling aport out'ofzthe chamber 3D. Thesevalves are not shown since they are or may be of conventional poppet type..

Let'it be further assumedfthata single gate-'or abutmentassembly such `as 45 is employed, with asingle piston I and .a cylinder 3 inthe form.

'35k Insuch a simplified construction, piston `I will, in the-.positionA shown, be compressing and displacing" fluid through thev of.a fulltorus, omittingfthe right h'and'cell and: adjacent valves.

upper valveSG tothe cell 30; thence outwardly thereofithrough the. poppet discharge valve. As

piston I approaches the gate 45 `the* upper valveY 36 is closed, and thelowerrotary valve 37' is opened. Piston I after traversing thegate, now draws a fresh chargethrough the intake poppet Valve via chamber 30 and through the lower r rotary valve 3l. While thus inducing a fresh charge of air, thepis'ton is compressing some air ahead of itself, and as it again approaches the gate, valve 36 is opened and 3l is closed; At this time, the poppet discharge valvemay open, depending upon its spring loading, but as the piston again traversesthe abutment, valve 31 remainingv closed, and vali/e36- again reopens. rIhus the piston displaces ahead of itself virtually a'full cylinder of fluid which is driven outwardly through valve 36, chamber or cell 30, and therefrom through the spring loaded discharge valve.

It will have appeared that the duplication of the structure described as in Fig. 2, will result inan operationquite similar to that described, except with shortened stroke and 'more `frequent discharge pulsations. .Obviously if desired, theplurality of cylinder assemblies, for example as shownby Fig. 2; may be used for'increased ca pacity, or may be used for consecutive cycles of displacement as in lmulti-stage operation.

It will now appear thatA the arrangement identified with the improved piston, cylinder and abutment gate of the present design, serve fully to attain each and all of the several objects hereinabove expressed, as well-as many' others implied from the more detailed 'description of parts and assembly.

Although the invention-has been described byA making; particularized..reference to a selected` embodiment of the'. invention,` the :detail of'idee f scription" is to vbe. understood' solely.= in an .in-'- structive rather'. than'in a limiting sense, nu-

merousvariants beingpossible withinfthe scope of the claims hereunto appended.

We claiml asour." invention:

1. A piston adapted for use in a toroidalcylinder 'andffin traversing relation .to a' wiping and sealing piston-.gatestructura the piston being characterizedbyra bodyv portion and a nose portion; the ynose .portion .beingY substantially apexed at itsforwardror leading. end,v and being formed. rearwardly `of its'forwardend to present a seriesv of transverse cross sections each of which exhibitsv a major axis and a minor axis of substantialY symmetry, with'one of said'axes `terniii'iating in dened, substantially rectilinear and longitudinal edge portions.

2..A piston adapted for use ina toroidal cylinder and intraversing'relation to awiping and' sealing piston-gate structure, the piston including a `body portion and a nose portion, the nose portion being provided with a substantially pointed leading end and rearwardly of its leadin'gend, being characterized by convex, substantially reg.. ularlycurved sides,` and presenting'a-seriesfof cross sections each exhibiting a major anda minor axis of symmetry, the 'convex sides of the nose yportion being drawn on centers each lyingv substantially on a minor' axisof symmetry, and

the convex sides intersecting to form substantially linear, angulate, rib-like protub'erances.V

3. In a piston adapted for use in a toroidal cylinder and in traversing relation to awiping andsealing piston-gate structure, the pistonincluding a-b'ody portion and a nose portion, the

body portion being substantially cylindrical'and the nose portion being characterizedby convex opposite sides so related as to result in a-seriesv erall'y horn-shape, and constructed to present a.

series of cross sections'increasing in area from the leading end of .the nose portion to a zone near the body portion, each Suchcross section exhibiting a major axis and aA minor'axis of symmetry, and the sides of the portions of the nose'including the said sections, intersecting along oppositev margins of the nose in a manner to form in suchVv zones of intersection, substantiallyA sharp and substantially linear ridge portions.

5. In a piston of a type for use in a toroidal cylinder and in cooperative relation with a wiping and sealing abutment structure traversed by the piston, a body portion and a nose portion, the

nose portion lhaving an attenuated leadingv end,

and rearwardly thereof being characterizedfby a series of transverse sections each of double convex` aspect and increasing in both depth and width from a zoneY near the leadingend of the nose,

to a zone near the body of the piston, the nose` being thus yprovided with distinct angulate ridges along its top and bottom surfaces, the body being of substantially circular cross sections rearwardly of -the nose por-tion.

6. In a piston adapted for use in a toroidal cylinder and in cooperative relation with a wiping and sealing piston abutment structure arranged to be traversed by the piston, the piston including a substantially cylindrical body and a nose of a generally horn shape pointed at its leading end, the nose being characterized by a series of transverse sections each increasing in area rearwardly of the nose and each conforming in area and shape to an overlapped area of partly overlapping circles, the nose portion thereby being formed to present a pair of longitudinal, substantially linear, angular protuberances along its opposite sides.

'7. A piston adapted for use in a toroidal cylinder and in conjunction with a wiping and sealing piston-gate structure through which the piston is to pass, the Ipiston including a body portion of substantially cylindrical shape, and a long nose portion substantially apexed at its forward or leading end, the nose being convex on its opposite sides but of lesser width than the body whereby it presents a relatively laterally attened aspect, the convex sides of the nose portion sharply intersecting each other along opposite margins of the nose, to result in substantially rectilinear, protuberances of an angular section along opposite portions of the nose, said protuberances merging into the body in a Zone of juncture of the body and the nose.

8. A piston adapted for use in a toroidal cylinder, and in conjunction with a wiping and sealing piston-gate structure to be traversed by the piston, the piston including a body of substantially cylindrical formation and a nose substantially nini-QA a+ H-e Medina cmrl thn nnen hr2-incr nf suhand relatively sharp protuberance along each of two opposite portions of the nose and extending substantially from the pointed leading end 'of the nose back to the body, the nose being formed on an axis curved on substantially the same center as the toroidal cylinder in which the piston is to be used, the said axis of the nose being angularly related to the axis of the piston body in such manner that one side of the nose and one side of the body both lie substantially tangent to a common plane, and so formed that the 'apexed end of the nose lies substantially in said plane of tangency.

10. In a piston and cylinder assembly adapted for use as a compressor, a toroidal cylinder, a valved transfer chamber external to but communicating with the toroidal cylinder, and provided with a pair of passages from the chamber to said cylinder, a valve in each of said passages, a piston-wiping and sealing gate structure or abutment located to extend across the toroidal cylinder between the said passages, and a piston operating in the cylinder and in traversing relation to said wiping and sealing piston gate structure, the piston being characterized by a body portion and a nose portion, the nose portion being substantially apexed at its forward or leading end, and being formed rearwardly of its forward end to present a series of transverse vcross sections, each of which exhibits a major axis and a minor axis of substantial symmetry, with one of said axes terminating in defined, substantially rectilinear and longitudinal edge portions, the piston gate structure including cooperating elements adapted to define a port for the piston which port is of variable shape and area as traversed by the

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