US3957051A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pump-type syringe having double-acting piston construction
Assignee: MEDICAL DEVELOPMENT Corp
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Filing: 1974-09-13
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Granted: 1976-05-18
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Expires: 1994-09-13
Abstract
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 spring-loaded 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.
Inventors
- 👤 Silas Charles Topham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:41
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/178; A61M5/20; A61M5/204; A61M1/00; A61M1/60; A61M1/63; A61M1/80; A61M1/81; A61M1/64; A61M1/67
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
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 for 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.
Claim 2
Dependent Claim
112 words
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 for 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.
Claim 3
Dependent Claim
89 words
The syringe of claim 1 wherein said piston means comprises a hollow elastomeric piston having squared forward and rear surfaces, said shaft including a plunger retainer end constructed to sealingly engage said piston at said forward surface during return plunger strokes and fluid-bypass piston-support means engaging said piston means at said rear surface on forward plunger strokes; said piston being disposed between said piston-support means and said plunger retainer end, the distance between said piston-support means and said retainer end being greater than the axial dimension of said piston.
Claim 4
Dependent Claim
21 words
The structure of claim 2 wherein said fluid-bypass piston support means comprises a spider having a plurality of outwardly extending arms.
Claim 5
Dependent Claim
27 words
The structure of claim 1 wherein said piston is uniformty hollow and is constructed to receive said shaft such that a fluid shunting path is provided therebetween.
Claim 6
Dependent Claim
20 words
The structure of claim 1 wherein said port structure extends laterally outwardly from said barrel and includes a discharge tube.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |