US2708438A - Hypodermic syringe - Google Patents

Description

May 17, 1955 M. J. COHEN 2,708,438

HYPODERMIC SYRINGE Filed Nov. 13, 1951 l/IIIIIII I I llijzl INVENTOR MILTON J. COHEN ATTORNEY United States Patent HYPODERMIC SYRIN GE Milton J. Cohen, Washington, D. C., assignor to Miljam Instrument Corporation, Washington, D. C., a corporation of Delaware Application November 13, 1951, Serial No. 255,983 2 Claims. (Cl. 128220) My invention relates to a hypodermic syringe, and it is an object of the same to provide a self-contained syringe that shall hold a liquid medicament under such conditions that the contents may be kept in place indefinitely and shall not be liable to leak or evaporate.

The prime object is to lock the relatively movable barrel and plunger of the syringe in place so that neither can move endwise relatively to the other. This is accomplished by placing a special cap designed to receive and seal the end of the cannula, thereby rendering the plunger immovable so that the plunger cannot move either toward the nozzle end of the barrel nor away from that end, and so the liquid contents will remain in position ready for use, until just before the contents of the syringe are to be injected into the body of a patient, or into a wound, or upon an area to be treated.

Another object is to provide a syringe that can hold its contents indefinitely under storage conditions but which is so constructed that it is ready for instant use upon removal of a simple lock cap, and which syringe needs no assembly or other operations except as stated, wherefore an injection may be made by a person who is unskilled, or under adverse conditions as when the user is dazed as by battle conditions or as the result of trafiic accident or the like.

Another object is to prevent leakage or evaporation through the cannula, or between the plunger and the barrel, as by accidental movement of the plunger in handling, shipping, etc.

Another object is to provide a syringe that shall preserve separately a liquid medicament and another medicament which is soluble in said liquid or which is in powdered form, said medicaments being preserved in strict separation, but being so arranged that they may be injected by a single operation of the syringe.

Another object is to provide a device of the character described in which all parts except the actual hypodermic needle are made of moldable, form-sustaining plastic material such as Vinylite, styrene or some other of the Well known plastic materials having such desirable qualities as rigidity, transparency or translucency and resistance to heat, moisture and chemical action. The materials may obviously be varied to some extent according to the intended contents and conditions of use. While glass is not so desirable as plastics of the synthetic resin types, it may in some instances be desirable to form some parts of glass or of rubber.

Another object is to provide a syringe with means for safeguarding its needle against any possible contamination.

Referring now to the drawings annexed hereto, which are made a part of this application and in which similar reference characters indicate similar parts:

Fig. 1 is a longitudinal view of a preferred form of my invention, partly in section.

Fig. 2, a similar view of the device, shown as in the act of discharging its contents, and

Fig. 3, a similar view of a modification.

1 amount of such material.

In the drawings, reference character 10 indicates the barrel of a syringe, which is provided at its forward end with a hub 11 that is, as is also an annular flange 12 at the rear end of the barrel and a head 13 at the forward end of the same. The outer face of the hub is corrugated as at 14.

A hypodermic needle 15 projects forwardly from the' hub 11.

A cap 16, preferably is made of a flexible plastic material that is somewhat elastic, at least adjacent its open, or skirt end, said cap being preferably internally corrugated at its open end, as at 17, though under some conditions the surfaces at 14 and 17 may be concentric cylindrical, and simple friction may be relied on to hold the cap in place at the forward end of the barrel. There should, of course, be an airtight fit between the contacting surfaces of the cap 16 and the hub 11. The cap may even be of material such as can be readily broken or torn ofi when an injection is called for. Such a combination will safeguard the contents of a syringe against loss by leakage or evaporation under practically any conditions of storage and handling.

In the preferred form of the invention, the end of the cap at 18 will consist of some material into which the end of the needle can penetrate to an extent to seal the passage through the needle or will contain an appropriate Various semi-hard or elastic plastics will suggest themselves to those skilled in the art, rubber being one such material.

The plunger 19 is hollow for lightness, and may be of any suitable material. It preferably fits so closely in the barrel 10 as to preclude any loss of contents at the rear end of the syringe by leakage or evaporation or other cause. If the contents of the syringe include highly volatile liquids, or if the nature of the materials of the barrel and plunger precludes such close tolerances as to prevent loss of liquid without employment of other measures, a flanged plug 2% of rubber or other suitable material may be inserted into the front end of the plunger, which may be hollow at this point to receive the plug. One advantage in using a rubber plug 20 resides in the fact that the inner end of the needle 15 ordinarily extends inward past the head 13 and so prevents ejection of a small portion of the liquid medicament. As a further means for insuring that all the contents shall be ejected, a thin grommet at 23 may be provided to fill the space about said end of the needle. An annular flange 21 is shown at the rear end of the plunger for convenience of the user, who may press his thumb against the plunger while holding two fingers at the forward side of flange 12, or abutments of other forms may be substituted for that purpose, as may readily be understood.

Fig. 2 shows the syringe with its cap removed and its plunger in such position as it will assume upon partial discharge of the contents of the syringe.

In Fig. 3 there is shown a modified form in which the outer barrel 10' may be as before, but which has a hollow plunger 25 with an annular flange 26, and an inner plunger that may be hollow or of solid form, the plunger 27 having a head 20 and a rear annular flange 28. Beyond the forward end of the solid inner plunger there is a compartment in the hollow plunger that is filled with a powder 29, or other suitable medicament that is to be kept separate from the liquid in the compartment 30 for some such reason as that the one medicament would react with the other upon contact. The hollow plunger has a head 31 that extends across the inside of the barrel and fits tightly against its walls. If the material in the hollow plunger is non-liquid no special head or washer need be used, but otherwise expedients such as above mentioned may be employed.

In the use of the form of the invention shown in Fig.

3, the liquid at 36 is separated from the powder at 29 by a relatively thin membrane 31. When the medicament is to be used the outermost hollow plunger 27 is pressed inward by action of the thumb on the thumb rest 28, the fingers grasping the flange 26. Due to the locking action of the cap and plunger by the pressure seal principle of physics as in the lift-pump, by which the hollow plunger is held in position in the barrel, it is impossible to force the hollow barrel to eject the liquid accidentally before the cap is removed, though the liquid can be forced out, if desired, after removal of the cap, so that the powder may remain in its chamber if not needed.

The end of the needle will enter into the yieldable material 18 of the cap, when the syringe is loaded to the desired extent, far enough to close the needle opening and effectively prevent egress of any liquid even by heavy pressure on the plunger since the liquid is incompressible, nor can the plunger be withdrawn, since the liquid is inelastic. Since the entire device will be so inexpensive that it may be discarded after a single use there will be no diificulty about sterilization, the needle being sterilized at the time of manufacture of the syringe, and there being no occasion for subsequent sterilization.

It may be sufficient in some cases to rely on a close fit of the cap about the hub, or about the adjacent end of the barrel of the syringe, to hold the cap in place in such a position that the point of the needle will bury itself in the soft material at 18.

Preferably, but not necessarily, the cap in each form of the invention will be filled with absorbent material, such as cotton, cellulose, felt or other soft fibrous aggregate, as shown at 32, that is impregnated with an ointmentor paste-like material containing a germicidal agent.

This serves a double purpose in that it helps to prevent contamination of the needle that penetrates it, as shown, and the ointment may be used to sterilize an area of skin at the place to be penetrated by the needle, which is considered a proper procedure before insertion of a needle into the flesh.

This application is a continuation in part of my application Ser. No. 247,522, filed September 20, 1951, now abandoned.

It will be obvious to those skilled in the art that many changes may be made in the devices herein disclosed, all without departing from the spirit of the invention; and therefore I do not Limit myself to what is shown in the drawings and described in the specification, but only as indicated in the appended claims.

Having thus described my invention, what I claim is:

l. A hypodermic syringe, including a barrel, a. hollow plunger fitting closely in the barrel, a hollow needle proiecting from one end of the barrel, a cap covering the needle and fitting closely over the needle end of the barrel and sealing the needle, a solid-ended plunger in the hollow plunger, a liquid medicament in the barrel forwardly of the hollow plunger and a fluent medicament confined in the hollow plunger forwardly of the solid-ended plunger.

2. A disposable hypodermic syringe, including a barrel, a hollow plunger fitting closely in said barrel, a solidended plunger in the hollow plunger having a liquid in a cavity back of its end, a needle projecting forwardly of the barrel and communicating with said cavity, and a cap covering said needle and having elastic material in its end for occluding the point and channel of the needle and forming a vacuum block in the needle, thus preventing movement of the plungers.

References Cited in the file of this patent UNITED STATES PATENTS 1,115,561 Northey Nov. 3, 1914 1,234,582 Trueblood July 24, 1917 1,279,069 Yoshida Sept. 17, 1918 1,687,502 Marcy Oct. 16, 1928 2,400,722 Swan May 21, 1946 2,551,339 Ryan et a1 May 1, 1951 2,551,414 Burnside May 1, 1951

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