04256109 is referenced by 487 patents and cites 14 patents.

The specification discloses an improved shut off valve for a canister and lid assembly used as part of a medical suction apparatus. The valve includes a cylindrical plunger made of a soft rubber-like material and having an upwardly facing concave disc integrally formed on the top of the plunger. When the fluid within the canister rises to a predetermined level, the plunger floats upwardly forcing the disc into a sealing relationship covering and blocking a suction port. Alternately, the soft rubber plunger may be dimensioned for use as a plunger cap for the upper end of a hard plastic plunger.

The soft rubber plunger and integral concave disc are formed in a composite die, including a disc die and a plunger die. Rubber is injected into the composite die through a bore to form the plunger and integral concave disc. To remove the rubber concave disc from the disc die, air is injected into a bore while the disc die is simultaneously moved away from the plunger die.

Title
Shut off valve for medical suction apparatus
Application Number
923346
Publication Number
4256109
Application Date
July 10, 1978
Publication Date
March 17, 1981
Inventor
Robert L Nichols
808 Ft. Worth St., Jacksonville, 75766
TX, US
Agent
Richards Harris & Medlock
IPC
A61M 1/00
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