US1534198A - Packing ring and piston - Google Patents

Description

April 21, 1925.

J. T. WILSON PACKING RING AND PISTON Filed April 26 1921 5 p 8 C L\ P w? 2 G L 3 v Patented Apr. 21, 1925 UNITED STATES Jom r WILSON, or PILOT HILL, canrronnm.

PACKING RING AND PISTON.

Application filed April 26, 1921; Serial No; 484,497.

To all whom it may concern:

Be it known that I, JOHN T. WILSON, a citizen of the United States, residing at Pilot Hill, in the county of Eldorado and State of California, have? invented certain new and useful Improvements in Packing Rings and Pistons; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

An explosive or gas engine piston usually consists of anintegral cylindrical casting provided with circumferential grooves in its exterior surface to receive packing rings which frictionally bear againstthe interior surface of the cylinder to form tight joints therewith during all periods of the reciprocating motions of the piston.

The front end of the piston and the packing rings which project slightly beyond the exterior surface of the piston are subjected to great pressure by the generated energy of the explosive charge. The packing rings necessarily are of small cross sectional area and cut apart so they can be sprung over the end of the piston into the grooves. Being of small dimensions, they soon wear out and the piston body then frictionally engages the interior surface of the cylinder and wears away the metal of the cylinder and opens up a passageway for the gases generated by the explosion. Also the ends of the rings frequently break and become displaced so the gases can pass. Under the same conditionswhen explosive charges are drawn into the explosion chamber, a vac uum being formed therein, lubricating oil from the crank chamber is sucked past the packing rings into the explosion chamber, where it becomes carbonized and fouls the cylinder and piston and rings.

- These conditions obviously impair the efliciency of the engine, and the remedy therefor does not consist simply in using wider packing rings, for the wider the ring the greater the pressure beneath it and the greater the friction between the ring and the cylinder.

One object of the present invention is to cure these imperfections by providing a packing ring of a shape substantially conforming to a novel shape of the groove in the piston and presenting a' relatively large area of exterior wearing surface and a much less area of surface at the interior to be'acted upon by the pressure of the explosive gases and the pressure of the explosive charge when being compressedth at is, to exclude from part of the interior or under surface of the ring the pressure due to the compression of the charge and also to the explosion of the charge; but when the charge is drawn in by suction, a vacuum being formed in the explosion chamber, permitting air at atmospheric pressure, containing more or less of lubricating oil, to

pass beneath the entire under-surface of the I packing.

Another object is the provision of a ring with a circumferential oil groove in its exterior surface and compensating for the lessened exterior wearing surface thus occasioned, by increasingthe width of the exterior bearing surface of the ring at the edge thereofadjacent the crank chamber. A further object is the provision of an oil groove between the edge of the ring adjacent the crank chamber and the wall of the groove in the piston adjacent the said edge of the ring.

A further object is the provision of a packing ring with an acute angle or sharp edge at that edge of the ring adjacent the crank chamber and functioning to scrape the excess of lubricating oil from the interior surface of the cylinder and into the crank chamber when the piston moves toward the crank chamber.

Finally, the invention consists in certain novelties of construction and .relative arrangements, as herein set forth, of the a ring, the groovein the-piston adapted to receive the ring, and the crank and explosion chambers? v Theaccompanying drawing illustrates an example of the embodiment of I the invention constructed" and the parts combined ac cording to the best of the several modes of procedure I have so far devised for the attainment of the ends set forth.

Figure 1 is a vertical section in elevation of a gas engine piston and cylinder showing my invention, the packing rings also being in section.

Flgure 2 1s a slde view in elevatlon of the ring showing the ends sprung apart and slightly separated, and'the lap joint.

Figure 3 is a top plan view of the ring as shown by Figure g,

' I Figure 4 illustrates the position of the nates a piston of a well known general shape and construction, exclusive of the shape of one groove in its exterior surface. The lines B-B and sectionlines respectively represent part of the interior circular surface of the engine cylinder, presenting a smooth surface tl1roughout,and part of the metal of the cylinder. C is the end of the piston forming the movable inclosing boundary of the explosion chamber D,"and E is the end of the piston facing the inclosed crank chamber space F which generally contains a heavy lubricating oil or other lubricant. G designates the groove of novel shape in the exterior surface of the metallic body of the piston. R is the improved packing ring in groove G, and S is a ring of common con struction. 7

Referring particularly to the combined novel shaped groove G and ring R, it will be noted that each substantially is adapted to the shape of the other. The outer part of the groove G is of the same width throughout the circumference of the piston. Itsdepth. at 2 adjacent the end of the piston next to the explosion chamber is greater than its depth at 3 adjacent the crank chamber end of the piston. The surface 4 of the wall defining the groove is vertical, and the surface 5 oblique to the axis of the piston, as shown.

The ring R has a circumferential oil groove 6 of the shape illustrated in its exterior surface, a flange 7 with an acute angle or'sharp edge 8, and the ring substantially fits the groove except at the flanged edge, where a slight open space is provided constituting an oil groove 9. This oil groove is the open space between the surface 5 of the groove in the piston and the oblique surface of the flange 7 adjacent thereto, and the size of the space depends upon the relative angles of the surfaces mentioned, as is obvious. K

The ring is of resilient metal and, to allow of its being sprung apart and slippedover the end of the piston, it is cut apart and the free ends, in this instance, fashioned to form a leak-proof joint. Referring to Figures 2 and 3, a recess or seat with a plain bearing surface 10, 11 is formed at one end of the ring by milling or otherwise, the bearing surface at 11 being of the full Width of the ring.

The metal at the under surface at the other,

. the side and bottom surfaces thereof and the surfaces defining the groove in order that the ring .may float longitudinally relative to the axis of the piston and also at right angles thereto so as to frictionally engage the interior surface of the cylinder throughout should the parts be out of center.

It should be noted here that in gas engine practice, unlike that when steam is the motive power, the packing ring must loosely fit the groove in the piston so that when the ring and groove become fouled by the products of incomplete combustion of the charge, which is always the case more or less, the

ring will not stick in the groove. That is,.

the ring shouldhave some slight side play within the groove so it will not pack and be prevented from expanding against the interior surface of the cylinder.

The ring in the operation of the engine is subjected to three varying pressures.

First, when the charge is drawn-in, a vacuum being formed in the explosion chamber, air and oil at atmospheric pressure, at 15 pounds to the square inch or less, pass to the entire under surface of the ring which does not excessively force the ring against the interior surface of the cylinder, but sufliciently\to prevent the passage of oil beyond the ring to the explosion chamber. The pressure against the entire under surface of the ring is not sufiicient to cause excessivi friction and wear-of the ring, so a quite wide wearing ring may be employed under these conditions. The ring occupies the position shown in Figure 4, the surfaces of the ring and groove at M being in frictional contact :so as to form a tight joint against the pas sage of air or oil.

Secondly, when the charge is being compressed, the ring shifts to the positionshown in Figure 5, the mixture under compression passing to the space 0 beneath only part of the under surface of the ring, the surfaces of the ring and groove at P forming a tight joint so the pressure cannot reach the under surface of the ring flangef.

Thirdly, when the explosion of the charge 'is taking place the ring under very great pressure maintains its position shown in Figure 5 and excludes pressure from the under surface of the'flange of the ring.

Under the last two conditions enumerated the pressure under part of the ring is suflicient to force the ring into frictional contact with the interior surface of the cylinder which is liable to break, and the ring is not forced against the interior surface of the cylinder by great or excessive pressure during the explosion of the charge, for the greatest pressure, due to the explosion of the charge, is, excluded from part of the under surface of the ring. It is also clear that oil from the crank chamber cannot pass the ring when a vacuum is caused in the explosion chamber for drawing in the explosive charge.

Also the second object of theinvention'is attained by the presence of the flange 7 for it increases the area of the exterior wearing surface of the ring to an extent equal to or in excess of the area of bearing surface removed by the formation of the groove 6.

The third object of the invention is attained by the relative formations of the edge of the ring adjacent the crank chamber and the wall of the groove adjacent thereto, the oil groove 9 thus provided being of ample dimensions and opening in the direction 9f the crank Ghamber.

The fourth object of the invention obviously is attained, the sharp edge 8 of the ring being effective in scraping the excess of oil backwardly into the crank chamber, and

' the flange 7 being isolated under all conditions of service so pressure of the gases generated by the explosion of the charge cannot reach its under surface.

The modification of the ring shown by Figure 6 consists in making the ring of two parts assembled to form one ring, as shown.

A relatively large bearing surface is secured so the ring Wlll wear much longer than a narrower ring While I have illustrated only one of my improved packing rings and in a groove especially shaped to receive it, any desired number of such rings may be present.

lVhat I claim is 1 The combination with a cylinder and piston having a circumferential groove wider adjacent the exterior surface of the piston than at the bottom, the greatest depth of said groove being adjacent the explosion chamber, of a cut resilient expansible flanged packing ring of a shape in cross section substantially matching and loosely fitting the groove, its exterior surface frictionally engaging the interior surface of the cylinder, the flange extending beyondthe vertical surfaces of the groove and ring at P, the entire edge surface adjacent the explosion chamber being in a plane at right angles to the longitudinal axis of the piston, and the free ends being fashioned to form a lapped joint; the end of -the piston next the explosion chamber being entirely closed so that explosion and charge compression pressures can reach the under surface of the ring only .by passing over the outer edge of the piston, the vertical surface of the groove and the vertical surface of the edge of the ring remote from the explosion chamber at P matching to form a tight joint and'the flange of the ring and the wall defining the shallow portion of the groove each having a surface oblique to the axis of the piston and said surfaces spaced apart to form an oil groove.

2. The combination with an explosive engine piston having a circumferential groove, of a flanged packing ring therein provided with a circumferential oil gropve, the width of the bearing surface of the flange being sufficient to compensate forv the lemened exterior bearing surface of the ring due to the removal of metal to form said 011 oove.

In testimony whereof I aflix my s1gnature.'

JOHN T. WILSON.

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