Syringe

Abstract

A medicament applicator of the syringe type having a plunger sleeve slidable in the syringe barrel, the inner end of which has an integral severable circular closure, and a plunger slidably mounted in the sleeve and recessed to contain a solid medicament, the recess having an oval cutting edge to shear the closure from the plunger sleeve upon initial inward movement of the plunger, to expose the solid medicament to a solution container in the syringe barrel, whereupon further inward movement of the sleeve and plunger, the mixture is ejected.

Description

This invention relates to a syringe type medicament applicator containing a solution and a dry medicament adapted for mixing just prior to application.

The applicator syringe of this invention comprises three components economically produced by moulding from plastic material. The barrel of the syringe is adapted to contain the solution. A sleeve is slidably mounted in the barrel and is closed at its inner end with a severable disk integral closure. A plunger is slidably mounted in the sleeve and is formed at its inner end with an annular recess, to receive a medicament tablet. An actuating stem is formed integral with the plunger and extends through the sleeve and outwardly a short distance from the outer end of the sleeve. The recess has an oval cutting edge slidable along the sleeve wall for severing the disk on initial inward movement of the plunger to expose the solid medicament to the solution. Thereafter, the plunger and sleeve are moved in unison axially of the barrel for ejecting the mixture therefrom. The oval cutting edge engages the peripheral portion of the closure progressively to sever the same with a minimum of axial pressure on the plunger stem. Friction from the close fit of the plunger stem in the sleeve tends to prevent relative movement to effect severance of the closure except on positive pressure greater than would occur in the ordinary handling of the loaded syringe, or resulting from the syringe being dropped.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings wherein like reference numerals indicate like parts:

FIG. 1 is a lengthwise, sectional view of the syringe embodying my invention, the syringe being illustrated as loaded with the solution and dry medicament for shipment;

FIG. 2 is a view, similar to FIG. 1, showing the plunger initially moved inwardly, effecting severance of the closure from the inner end of the sleeve, and

FIG. 3 is a side elevational view of the plunger partly in section in assembly relation to the sleeve.

Referring to the drawings the syringe barrel 10 is shown with a sleeve 12 slidably disposed in the bore 14 of the barrel 10. The sleeve is formed at its inner end with an integral closure 16. The closure 16, at the joinder of its periphery with the sleeve bore 18, is of reduced thickness, as indicated at 20 to facilitate severance.

A plunger 22 is slidable in the bore 18 of the sleeve 12, and has an actuating stem 24, cruciform in cross section. The inner end portion 25 of the plunger 22 is formed with an annular recess 26, the outer portion of which is beveled as at 28 to provide an oval or elliptical knife edge 30 inclined to the axis of the plunger.

The internal bore 18 of the sleeve 12 adjacent the closure 16 makes a relatively close fit as at 23 with the inner end portion 25 of the plunger for a sufficient distance back from the end closure to frictionally resist movement of the plunger prior to the approach of the cutting edge 30 with the closure 16. Rearward of the close fit 23, the sleeve bore may be of slightly increased diameter and have a shallow relief groove such as 21, whereby insertion of the plunger will be relatively free and unable to trap air in front thereof to prevent the closure from being blown from the sleeve end upon insertion of the plunger. Thus the end closure is easily cut free, subject to overcoming the frictional resistance.

The closed end of the barrel 10 is formed with a neck portion 36 having a discharge passageway 38 closed by an integral finger grip portion 40, which is joined to the neck 36 by a side wall having an annular groove 42 to facilitate breaking away the grip portion to expose the passageway 38, after which a canula as at 44 may be applied.

The three components of the syringe are sterilized, and a quantity of solution, indicated at 50, which may be sterile water, is placed in the barrel 10. The sleeve 12 is then inserted a short distance in the barrel 10. A dry medicament 52, which may be in the form of a pill, is placed in the recess 26 of the plunger 22, and the plunger then inserted in the sleeve 12, with the knife edge 21 of the plunger in proximity to the sleeve end closure 12 where frictional resistance to further movement is felt. The syringe is now loaded with the solution, and the solid medicament, and may be shipped in this condition.

In use, the sleeve 12 is grasped between the fingers, and the stem 24 moved inwardly against the frictional resistance. This initial inward movement of the stem 24 and plunger 22 moves the oval knife edge 30 thereof progressively against the reduced thickness of the closure periphery 20, effecting severance of the closure from the sleeve 12. This exposes the solid medicament or pill 52, to the liquid 50, in which it dissolves. Thereafter, the syringe barrel 10 is grasped between the fingers, and the sleeve 12, together with plunger 22, are moved inwardly as a unit, forcing the mixture through the discharge passage 38, and the canula 44, which has been applied after breaking away the tip 40. The stem 24 may be formed with a circular flange 32 for limiting inward movement of the plunger in sleeve 12, as shown in FIG. 2. It may so limit the movement as to prevent the knife from cutting the closure completely from the sleeve if desired.

While a single form of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

Claims

What is claimed is:

1. A medicament applicator of the syringe type comprising:

a. a tubular body having an internal cylindrical bore of uniform cross section with one end open and the other end having a neck portion with a sealed discharge passageway;

b. a tubular sleeve having an outer diameter at one end slidable in sealed relation within the cylindrical bore of said body;

c. said sleeve having an internal cylindrical bore open at one end and closed at the other end with a circular disk having an annular groove reducing the thickness of said disk at the juncture thereof with said other end of the sleeve bore, said sleeve bore including a portion of reduced diameter for a relatively small portion of its length adjacent said other end and a longitudinal groove extending from said reduced diameter portion to said one end;

d. a plunger of cylindrical cross section for a relatively small portion of its length at one end, said portion having an outer diameter slidable in sealed relation within the cylindrical bore of said sleeve and in tight frictional engagement with said portion of reduced diameter;

e. internal walls defining a recess extending from an open end defined by a sharp terminal edge axially into said portion of said plunger, said recess being fully closed except at said open end;

f. the relative lengths of said body, sleeve and plunger being such that said disk is severed at said annular groove upon full insertion of said plunger into said sleeve, and said other end of said sleeve is adjacent said other end of said body upon full insertion of said sleeve into said body.

2. The invention according to claim 1 wherein said plunger is of cruciform cross section along other than said portion of its length.

3. The invention according to claim 1 wherein said sharp terminal edge is oval in shape, said plunger being terminated in a plane not normal to the axis thereof.