Light-weight piston assemblies

#This invention relates to light-weight piston assemblies and, more specifically, to improved piston assemblies having piston bodies formed of light-weight metal and hard metal ring groove protection bands.

#Prior art of possible relevance includes French Pat. No. 634,700 issued Nov. 30, 1927 to Ceskomoravska-Kolben Akciova Spolecnost and the following U.S. Letters Pat. Nos. 1,547,687 issued July 28, 1925 to Rohwer; 1,547,737 issued July 28, 1925 to Daiber; 2,266,192 issued Dec. 16, 1941 to Grieshaber; 2,340,919 issued May 30, 1944 to Starr; 2,361,095 issued Oct. 24, 1944 to Harrah; 2,398,577 issued Apr. 16, 1946 to Bratzel; 2,478,179 issued Aug. 9, 1949 to Brockmeyer; 2,759,461 issued Aug. 21, 1956 to Maybach et al; 2,807,247 issued Sept. 24, 1957 to Cramer; 3,215,130 issued Nov. 2, 1965 to Maier; 3,380,556 issued Apr. 30, 1968 to Whitehead; and 3,385,175 issued May 28, 1968 to Meier et al.

#The advantages of light-weight piston assemblies in reciprocating mechanisms, particularly engines, have long been recognized. In general, such piston assemblies are formed principally of light-weight metal such as aluminum or aluminum alloys and are typically provided with a ring groove protection band formed of a hard metal, such as cast iron, which carries one or more compression rings. The use of such bands has been necessary to provide long life to the piston assemblies in that, as is well known, during operation of reciprocating mechanisms embodying such piston assemblies, the minute movement which the piston rings undergo during the operation of the reciprocating mechanism would cause rapid deterioration of ring-receiving grooves if the grooves were formed directly in the light-weight, and generally softer, piston body.

#Other objects and advantages will become apparent from the following specification taken in connection with the accompanying drawings.

#FIG. 1 is a sectional view of a piston assembly embodying the invention;

#FIG. 2 is an enlarged, fragmentary view of one spring used in the assembly; and

#An exemplary embodiment of a piston assembly made according to the invention is illustrated in FIG. 1 and is seen to include a body, generally designated 10, formed of a light-weight material such as aluminum, magnesium or alloys thereof.

#The body 10 is generally cylindrical in shape and has an upper crown 12 provided with a crater 14 to optimize combustion when the piston is employed in a reciprocating engine. The body 10 also has a depending skirt 16.

#The assembly includes an interior, wrist pin and piston rod receiving cavity 18 and a transverse bore 20 for receipt of the wrist pin.