US1717750A - Piston for internal-combustion engines - Google Patents

Description

June 18, 1929. c. H. WILLS PISTON FOR INTERNAL COMBUSTION ENGINES Filed Oct. 13, 1924 Patented June 18, 1929.

UNITED STATES PATENT OFFICE.

PISTON FOR INTERNAL-COMBUSTION ENGINES.

Application filed October 13, 1924. Serial No. 743,254.

My invention relates to pistons for internal combustion engines and an object of my improvements is to lessen their range of variation temperature in use. I

I se re this object among others in the device illustrated in the accompanyingdrawa, indicatesthe piston as a whole. 0, 0,

are thegrooves for the packing rings and 20. b, b, are the rings in the grooves c, c.

The piston is made of non-ferrous metal such as aluminum alloy, or magnesium alloy, and is of the usual hollow construction open at its lower end toward the crank case. The upper part of the interior wall is provided with. ridges e, which in this instance have the shape of coarse screw threads, and the end wall is provided withridges of a similar shape in cross section extending -0 across said wall. These ridges are formed by providing a sectional core divided into parts v as indicated by the lines It and m, Fig. 2,

forming a coarse screw thread on its cy1in-' drlcal surface and transverse ridges, on its.

end. After the piston has been cast the central piece of the core is removed directly, after which the other parts of the core may be severally moved inward to disengage-them from the casting and then removed directly from the mold. i

d, is a shell of iron placed upon the outer cylindrical surface of the piston by elec trodeposition and over the interior wall surface. The iron shell extends over thewalls ofthe-ring grooves and over the surfaces of the ridges e and, f. The thickness of the shell is much exaggerated in the drawing. The upper end ofthe piston is a nonabsorbent of radiant heat. It may be of the same material as the body of the cylinder piston all metals that are nonabsorbent of structing joint.

ind polished and bright to reflect the radiant eat. Y

The iron shell is adapted to radiate heat readily, and also to form a durable wearing surface at the portion that comesin contact with the wall of the cylinder.

The rings, 7), b, are of iron and receive heat by contact with the walls of their grooves and they also absorb heat radiated rom said walls and impart the heat thus received to the cylinder walls 71. and lubricating ,oil by contact and radiation.

The iron forming the inner surface of the piston radiates heat readily, which radiated heat is absorbedby'the small particles of lubricating oil floating as a mist in the interior of the piston.

The ridges e and f present a large cooling surface which is washed by the material dashed into the piston by the rotation of the cranks. v

With the above described construction the range of temperature variation is so small "that the piston expands with the iron cylinder and the clearance may be small.

While I have-described a particular construction for increasing the area of cooling surface, as ridges e and f, clearly other forms extending over a considerable portion of the interior of the piston may be substituted therefor. I Nonabsorbent is of course a relativeterm as referring to the action of a substance, or

surface, exposed to heat.

lVhile' for distinctness I have defined my invention in the claims as consisting of a piston of nonferrous material with iron deposited thereon by electrodeposition I claim a range of equivalents for the metal of the I radiant heat, and for the covering metal all metals that are good radiators of heat when they are intimately united with the metal of thepiston, so as to obviate any heat ob- What'I claim is v v 1. A hollow piston having-an uncovered cylindrical inner surface and acooling ridge for dissipating vthe heat therefrom, said ridge being shaped in a spiral form whereby m0 the said ridge may be best with the piston bustion engine of nonferrous metal, such as and the pattern be removed by turning. aluminum ormagnesium, havin the walls 10 2. A piston for an internal combustion of its hollow portion covered w1th iron by vengine of nonferrous metal, such as alumielectrodeposition. num or magnesium, having its outer cylin- In testimony whereof, I sign this specifidrical surface covered with iron by eleocation. trodeposition thereon.

3. A, hollow piston for an internal como. HAROLD WILL-S.

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