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US 6,004,300 AGranted
Composite hypodermic syringe piston
OwnerRobert M Butcher, Sherman M. Brod +1inventors
InventorsRobert M Butcher, Sherman M. Brod, Sandra Crane Brod
Life of this patent
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OwnerRobert M Butcher, Sherman M. Brod +1inventors
InventorsRobert M Butcher, Sherman M. Brod, Sandra Crane Brod
Estimating the term…
A process for forming a composite piston of at least two materials, preferably a rigid material and an elastic material, the materials being chemically fused in a modular mold, and the plunger formed thereby. The process comprising injection molding one of the rigid material and elastic material in a mold to form a first piston part; forming a cavity in the mold adjacent the first piston part; injection molding the other of the rigid material and plastic material in the cavity to form a second piston part in contact with the first piston part; and removing the piston having a rigid part and an elastic part from said mold. Upon opening of the mold, complete, finished pistons are presented. The material for forming the elastic part preferably includes a lubricant. The process reduces assembly costs, quality control concerns, and contamination due to human contact.
A piston comprising a rigid inner sheath part and a resilient elastic outer sheath part, wherein said inner sheath part includes an internal surface defining an engagement cavity having a mouth to receive a plunger shaft end, with a mechanical locking collar at said mouth that is capable of reliably securing the plunger shaft in place and an external surface defining a conical apex opposite said mouth and an outer cylindrical surface for receiving said outer sheath;
A piston comprising a rigid inner sheath part and a resilient elastic outer sheath part, wherein said inner sheath part includes an internal surface defining an engagement cavity having a mouth to receive a plunger shaft end, with a mechanical locking collar at said mouth place, and an external surface defining a conical apex opposite said mouth, and an outer cylindrical surface for receiving said outer sheath;
Dependencies are inferred from the claim text.