US1388279A - Piston for engine-cylinders - Google Patents

Description

Patented Aug. 23,1921;

C. A. MARIEN.

PISTON FOR ENGINE CYLINDERS. APP/LICATION FILED OCT- 29, I92O- I ar/e351 flarzn/ jects sought is to make use of pistons cast" its alloys) eflicient' of expansion, so that an ordinary.

UNITED STATES CHARLES A. MARIEN, OF ST. LOUIS, MISSOURI, ASSIGNOR TO H. 86 H. MACHINE CO]!!- PANY, OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

PISTON FOR ENGINE-CYLINDERS.

Specification of Letters Patent. Patented Aug, 23, 1921;

Application filed October 29, 1920. Serial No. 420,360.

To all whom it may concern}- Be it known that I, CHARLES A. MARIEN, a citizen of the United States, residing at St. Louis, State of Missouri, have invented certain new and useful Improvements in Pistons for- Engine-Cylinders, of which the following is a full, clear, and exact description, reference being had to the accompany-' ing drawings, forming a part hereof.

The present invention is directed to improvements in piston construction, and particularly to pistons intended for pse in internal combustion engines. One of the obfrom aluminum or its alloys to secure lightness, and at the same time secure a fit between the piston and walls of the cylinder that will not only arrest or prevent sideslapping of the piston but will insure against the passage of any oil past the piston into the combustion chamber of the engine. .As'

well understood in the art, aluminum (and has a comparatively high coaluminum pitson in an internal combustion engine must when cold, fit with considerable looseness in the cylinder to allow for subsequent expansion by the heat of the gases to which the piston is exposed while the engine is running. When operating at a high temperature (as a result of high speed) the piston by reason of expansion may of course maintain proper contact with the walls of the cylinder; but when the temperature drops (as when running at low speed) the contraction of the piston allows so much clearance between it and the cylinder walls as not only to cause side-slapping, but at the same time permit aflow of oil past the piston (and packing rings) into the combustion chamber and thus give rise to engine trouble. Onthe other hand, if an aluminum piston has the desired fit when cold, it will bind against and cut or score the cylinder walls when heated, and thus interfere with the free operation of the engine. With my improvement I not only avoid side-slapping of the piston but insure against the passage of oil into the combustion chamber under all working conditions by providing the skirt of the piston with a series of longitudinal 'slits' and resilient skirt sections between the slits, said resilient sections being maintained in permanent and proper working engagement with the cylinder walls by the outward spring of the metal, the necessary rigidity belng imparted tothe skirt by a series of longitudinally slit tubular metallic filler strlps inserted into suitable cylindrical enlargements of the slits of the skirt, said strips permitting the skirt to. expand and PATENT. OFFICE.

contract both radially and circumferentially with any changes of temperature to which the piston is subjected. The advantages of my improvement will be fully apparent from the following detailed description in connection with the accompanying drawings in which-- 4 Figure 1 represents a middle longitudinal section through the cylinder and crank case of an internal combustion engine, showing my invention applied thereto; Fig. 2 is ahalf elevation and half middle longitudinal section of a piston showing the invention on a larger scale; Fig. 3 is an end view of the piston on the side facing the crank-case; Fig.

4 is a longitudinal sectional detail on theline 4-et of Fig. 8; Fig. 5 is an enlarged cross-sectional detail on the line 55 of Fig. 2; and Fig. 6 is -a perspective of one of the resilient split filler tubes detached.

. Referring to the drawings, C, represents the cylinder, C, the crank-case, P, the piston, and R, the connecting rod coupling the piston to the crank-arms A, as well understood in the art. The upper portion of the piston is provided with any conventional form of packing ring 1 (three rings being shown in the present example), the lower portion or skirt of the piston (the portion nearest the crank-case) being provided with annular peripheral oil-distributing grooves 2 from which lead ducts 3 to the interior of the piston to return any excess oil back to the crank-case. These features I do not claim as they form no part of my invention, the latter being concerned with the slitting of the skirt and the manner of imparting rigidity thereto to prevent side-slapping of the piston. f

v In the form of the invention, as shown, the skirt of the piston is formed with a plurality of longitudinally disposed parallel slits 4 (four in the present example), said slits extending from a point substantially opposite the piston in 5 (inserted through the openings 0 of tide bosses 6) to the free end of the skirt (Fig; l), the walls of the skirt at the slits being reinforced on the inside by ribs 7.- The walls of the slits 4 I are formed with the central tubular or cylinsaid enlargements nal edges of the tube adjacent the slit 8 thereof .being formed with an outwardly turned flange (1 adapted to be received by the slit 4 of the skirt preferably on the side facing the interior of the piston (Fig. 5), the thickness of said flange (and of-the walls of the filler tube) being less than, and approximately one-half the width of the slit? 4 to allow for the necessary circumferential expansion of the skirt at high temperatures.

ihe filler tube 8 extends substantially the .full length of the slit 4 (and its enlargement ,4 and by the natural tendency of the metal of which said tube is formed to spring outward, it hugs the walls of the enlargements 4' when the, piston is in service (Fig. 5). The filler tubes 8 serve to arrest the splashing (from the crank-case) of any oil through the slits 4 against'the cylinder walls, and any ,oil that may find its way into the tube through the relatively narrow passage between the flan e a and the opposite wall of i the slit by which it is received will simply run down the tub'e and be returned to the crank-case. The result is that any objec-i tionable flow of oil past the lubricating surfaces of the piston into the combustion chamher is, practically eliminated. .The filler I tubes likewise serve to impart rigidity to the skirt sections, thereby insuring a rigid skirt under all working conditions and preventing side-slapping of the piston.

'In practice, the skirt portion of the piston is cast slightly oversize, that is to say,

.slightlylarger than the bore of the cylinder,

after which the skirt is slit as shown, thereby imparting to the skirt sections between the slits'a resilience which a skirt. without the slits does notpossess. After the skirt has been a slit, the sections are slightly sprung inward and held in this position by a suitable jig or band, and the piston placed in a lathe and turned true and finished smooth. on the outside. When the skirt is released, theparts spring outward (dotted lines Fig. 2), so that when the iston is inserted into the cylinder thQSklIt hugs the walls thereof the. full length of the slits.

ile the skirt sections are free and out- I .wardly sprung, the tubes 8. are inserted into end carrying the. pistonrings the slit enlar ements. 4' throughthe' 0 en ends of the slits, the flanges a being pre erably (though not necessarily) passed into' a the portions of, theslits 4 on the side facing the Interior of the piston (Fig. 5). When the piston is inserted into the cylinder (the 1 bei in: serted first through the end-of the cylmder facing the crank-case, and-pushed toward the end facing the combustion chamber E), the outwardly sprung skirt sections gradulongitudinally ally'close over the filler tubes, causin a contraction or compression thereof against the tension of their outwardly sprung walls, the tubes thereby retaining their places in the slits under working conditions, the stiffness of the tubes preventing the skirt sections from yielding to the point where side slap; pingis' imminent. Obviously, with any rise 1n temperature the skirt sections will expand not only radially but circumferentially as Well. The radial component is taken care "of by 'the radial expansion of the walls .of the cylinder, and the circumferential component is taken care of by the slits 4, the

available widths of the slits between'the' flanges a and the opposite Walls of the slits being sufficient to accommodate the -max1 mum circumferential expansion that the skirt may undergo. When therefore the piston. with its resilient filler tubes' is once properly fitted into its cylinder, that fit is in no wise impaired with any rise 1n temperature, both components of the expansion- Which the skirt undergoes being taken care of, the skirt sections at all times maintaining their rigidity as a result of the support the same derive from the metallic tubular .fillers 8. The pressure of the skirt sections against the walls of the cylinder is such that while the necessary quantity of oil 1s permitted to flow or pass between the piston and cylinder walls for maintaining the desired lubrication. of the rubbing surfaces, no appreciable quantity of lubricant can find its way past the piston into the combustion chamber. E. The rigid filler tubes 8 not only prevent any materlal yielding of the skirt sections with the diagonal pulls and thrusts of the connecting rod R during the rotation of the crank-shaft, but adjust themselves by their resilience to the expansions and contractions which the skirt sections undergo with changes of temperature, the pressure of. the skirt ,against the walls of the cylinder remaining, substantially uniform under all working conditions. The slits 4 while hereshown as parallel to the axis of the piston may obviously be slightly inclined thereto without involving a departure from 115 the nature or spirit of the invention.

Having described my invention what I claim is:

1. A piston for engine cylinders provided Witha skirt slit or divided longitudinally, and longitudinally slit filler tubesin the slits of the skirt. V

2. A piston for engine cylinders provided with one or more longitudinal slits open at the free end of the skirt of the piston, and

slit resilient filler. tubes deposited in the slits of the skirt.

3. A piston for engine cylinders provided with a longitudinally slit skirt, 'the slits being open at the free end of the skirt, and suitable filler tubes mounted in the slits.

4. A piston for engine cylinders provided with a longitudinally slit skirt, the slits being open at the free end of the skirt, and

tions between successive slits, and resilient longitudinally slit filler tubes inserted in said skirt slits.

6. A piston for engine cylinders provided" with a skirt slit longltudina-lly and forming resilient outwardly springing members or sections between successive slits, the slits be ing formed wit-h central tubular or cylindrical enlargements, suitable longitudinally slit resilient filler tubes inserted in said enlargements, and outwardly turned flanges disposed along one of the longitudinal edges of the tubes adjacent the slits thereof received by the slits of the skirt at points outside of and adjacent to the enlargements, said flanges being of less thickness than the widths of the slits by which they are received.

7. A piston for engine cylinders provided with a skirt slit longitudinally and forming resilient outwardly springing sections between successive slits, the slits being formed with medial tubular enlargements, longitudinally slit resilient metallic filler tubes in serted in said enlargements, and outwardly turned flanges disposed along one of the .edgesof the tubes adjacent the slits thereof received by the slits of the skirt at points outside of and adjacent to the enlargements and facin the inside of the piston, said flanges belng of less thickness than the widths of the slits by which they are received to allow for the necessary circumferential expansion of the skirt sections.

In testim'ony whereof I afiix my signature, in presence of two witnesses.

CHARLES A. MAR-IEN.

Vitnesses: EMIL STAREK, ELSE M. SIEGEL.

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