Method and apparatus for making a two piece unitary piston
First Claim
1. A two piece unitary piston being adapted for use with an engine, said two piece unitary piston comprising:
- a head member being made of a material having a preestablished material strength, having a crown portion to which is connected a ring band portion defining a bottom surface, a support portion defining a support surface having a preestablished surface area, and an intermediate diameter having a preestablished value;
a skirt member being made of a material having a preestablished material strength being substantially the same as the preestablished material strength of said head member, having a ring band support surface being aligned with the bottom surface forming an interface, a mating portion defining a support surface being in contacting and supporting relationship with said support surface of said head member and an intermediate diameter having a preestablished value;
said intermediate diameter of said head member and said intermediate diameter of said skirt member forming an interference fit; and
said interface formed by said ring band support surface being aligned with said bottom surface being joined by a welding process.
1 Assignment
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Accused Products
Abstract
Past pistons have been susceptible to reduced longevity due to increased forces of combustion thereon during operating cycles of an engine. The present two piece unitary piston increases the longevity of pistons used with increased forces of combustion. For example, a head member has a crown portion defining a ring band portion having a bottom surface and a support portion. And, a skirt member defines a ring band support surface and a mating portion. The head member and the skirt member have a preestablished material strength being generally the same. The head member and the skirt member are joined at an interface of the support portion and the mating portion by an interference fit and are joined at the interface of the bottom surface and the ring band support surface by a weld. The force of combustion acting on the crown portion is resisted by the ring band support surface being in contacting relationship with the bottom surface. Thus, the skirt member structure supports and resists the bending moment of the combustion forces on the head member.
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Citations
20 Claims
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1. A two piece unitary piston being adapted for use with an engine, said two piece unitary piston comprising:
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a head member being made of a material having a preestablished material strength, having a crown portion to which is connected a ring band portion defining a bottom surface, a support portion defining a support surface having a preestablished surface area, and an intermediate diameter having a preestablished value; a skirt member being made of a material having a preestablished material strength being substantially the same as the preestablished material strength of said head member, having a ring band support surface being aligned with the bottom surface forming an interface, a mating portion defining a support surface being in contacting and supporting relationship with said support surface of said head member and an intermediate diameter having a preestablished value; said intermediate diameter of said head member and said intermediate diameter of said skirt member forming an interference fit; and said interface formed by said ring band support surface being aligned with said bottom surface being joined by a welding process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of making a two piece unitary piston, said method of making comprising the steps of:
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forming a head member having a bottom surface and a support portion defining an intermediate diameter; forming a skirt member having a ring band support surface and a support portion defining an intermediate diameter; positioning said intermediate diameter of said head member in interference fitting relationship with said intermediate diameter of said skirt member; positioning said support surface of said head member in contacting and supporting relationship with said support surface of said skirt member; positioning said bottom surface in contacting relationship to said ring band support surface forming an interface; and welding said interface of said bottom surface and said ring band support surface. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification