Title:
Syringe
United States Patent 3906947


Abstract:
A syringe having a one piece plastic cannula, piston and plunger.



Inventors:
CLOYD HAROLD S
Application Number:
05/098225
Publication Date:
09/23/1975
Filing Date:
12/15/1970
Assignee:
CLOYD; HAROLD S.
Primary Class:
Other Classes:
604/222
International Classes:
A61M3/00; A61M5/24; A61M5/315; (IPC1-7): A61M1/00
Field of Search:
128/237,234,213,215,218,260,261,265,220,221
View Patent Images:
US Patent References:
3378008Hypodermic syringe with vial1968-04-16Ogle
3066671Disposable additive container1962-12-04Cohen
2604095Disposable syringe1952-07-22Brody
2539510Hypodermic syringe1951-01-30Friden
2512568Hypodermic injection device1950-06-20Saffir
2448898Hypodermic needle1948-09-07Lockhart
0497250N/A1893-05-09



Primary Examiner:
Gaudet, Richard A.
Assistant Examiner:
Yasko J.
Attorney, Agent or Firm:
Hammar, Ralph
Claims:
What is claimed is

1. A syringe comprising a barrel closed fluid tight at one end and open at the other end, and a single piece of flexible plastic which forms the seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed and constitutes a cannula, piston and plunger,

2. The syringe of claim 1 having longitudinal ribs surrounding and fixed to said cannula.

3. The syringe of claim 2 in which said ribs have longitudinal edges fixed to a cylindrical wall.

4. The syringe of claim 1 in which the barrel is prefilled with the fluid to be dispensed and the fluid receiving end of the cannula is at all times in communication with said fluid.

5. A syringe comprising a barrel closed fluid tight at one end and open at the other end, and a single piece of flexible plastic which forms the seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed and constitutes a cannula, piston and plunger,

6. The syringe of claim 5 in which the plunger has a cylindrical wall slidably fitting the barrel and having its end inside the barrel integral with the cannula and the longitudinal edges of said ribs joined to said cylindrical wall.

Description:
This invention is a syringe which consists essentially of three molded plastic parts; a plunger, piston and cannula; a barrel; and a cap for the cannula.

In the drawing,

FIG. 1 is a longitudinal section on line 1--1 of FIG. 3 through a preferred form of syringe,

FIG. 2 is an enlarged fragmentary section of the piston, and

FIG. 3 is a section on line 3--3 of FIG. 1.

The barrel of the syringe is a fluid containing vial 1 closed at one end 2 and having a finger gripping flange 3 at its opposite or open end. The vial may be made of one of the flexible plastics such as polypropylene or other plastic compatible with the fluid contents.

The cannula 4, likewise of molded plastic, has its fluid receiving end 5 presented to the closed end of the barrel and has its fluid discharging end 6 projecting outside the open end of the barrel. The fluid discharging end is normally closed or protected by a cap 7 which may be of any suitable plastic or other material. The fluid receiving end of the cannula is integral with a circular end wall 8 having an integral hollow cylindrical peripheral flange 9 extending toward the open end of the barrel. Integral with the inner edge of the flange 9 is the inner edge 10 of an annular flange 11 extending outwardly at an acute angle toward the bottom wall of the barrel. The annular flange 11 is relatively thick, for example 30 mils, and is quite narrow or short as measured in a plane including the axis of the barrel for example one-eighth inch, so that it is relatively stiff. The outside diameter of the outer edge 13 of the annular flange is from 5 to 20 mils greater than the inside diameter of the bore of the vial so the deflection of the flange 11 results in adequate pressure between the edge 13 and the bore of the barrel so that the syringe can be shipped assembled and filled with the fluid to be dispensed. The outer edge of the flange 11 is not feathered so that adequate sealing pressure is built up by deflection of the flange to maintain the seal under static conditions. When fluid is being dispensed, the hydraulic pressure entering the groove 14 between the flanges 9 and 11 augments the sealing pressure. The end wall 8, flanges 9, 11 and junction 15 between the flanges comprise the piston. The junction 15 between the flanges 9 and 11 is joined to a cylindrical wall or plunger 16 which has a loose sliding fit in the barrel 1. The outer end of the cylindrical wall 16 terminates in a finger grip flange 17. A rigid support for the cannula 4 is provided by a plurality of axially extending ribs 18 having inner ends 19 joined to the end wall 8 and having inner and outer edges 20 and 21 joined respectively to the outer surface of the cannula 4 and the inner surface of the cylindrical wall 16.

All of the parts of the syringe are adapted to molding from plastic in simple molds resulting in low cost, high speed manufacture so the syringe may be used only once and thrown away. The particular syringe shown was designed to hold a fluid for the treatment of Mastitis.

The flexible plastic flange 11 has no tendency to stick to the barrel and does not require lubrication, an important advantage in syringes which are to be shipped assembled and filled.