Pump type syringe having double-acting piston construction
AssigneeMedical Development Corporation
InventorSilas Charles Topham
Life of this patent
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Abstract
A fluid-transfer syringe for medical usage wherein, by use of such syringe, fluid matter may be removed from an afflicted area, such as a knee, of a patient. The springloaded plunger of the subject syringe is provided with a piston constructed to have an automatic fluid bypass during forward strokes. The piston serves thereby as a double-acting piston for both drawing into the area forwardly of the piston the fluid to be expelled and, simultaneously, pumping previously expelled fluid from the syringe barrel to a provided outlet port.
Claims5
A pump-type syringe including, in combination, a syringe barrel having a cannula-receiving apertured end, rear finger-retainer means, and a rear closure;
- a cannula mounted upon said end;
- a plunger having a shaft sealingly journaled for longitudinal movement in said rear closure and provided with piston means operably disposed within said syringe barrel and so constructed to provide a baffle-type closure during plunger withdrawal strokes and fluid bypass during plunger forward-return strokes, said plunger also having a rearward, enlarged, thumb-depression end;
- a compression spring operatively interposed between said rear closure and said enlarged thumb-depression end;
- and drainage port structure provided said barrel rearward of said piston means for all dispositions of the latter.
Dependencies are inferred from the claim text.