Method for making swab applicators

[57] ABSTRACT

Swab applicators are made by extruding a plastic tube over a resilient mass of absorbent material. One end of the composite product is capped in such manner that when the cap is removed a portion of the absorbent material will be exposed to provide a swab tip. The applicator is then filled with a medicament or antiseptic fluid and the other end is sealed.

Claims, 9 Drawing Figures

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Patented May 9, 1972

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Sheets-Sheet 1

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Patented May 9, 1972

3,661,666

Sheets-Sheet 2

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3,661,666

METHOD FOR MAKING SWAB APPLICATORS

BACKGROUND OF THE INVENTION

Swab applicators are used for a great number of purposes, such purposes in many instances being of a single use character. For such reasons it is desirable that the swab applicators be simply and inexpensively made. This is particularly true in the case of surgical swabs where antiseptic considerations preclude more than one use of such devices. Desirably such swab applicators should provide for convenience in use, be easily and readily openable, retain their sterile character if surgical swabs, and offer no hinderance or hazard to the object with which they are used. Many types of swab applicator construction are known in the art, but generally the construction of such devices is more complex than that which would allow for cheap mass production manufacture essential for single-use devices. For example, applicator swabs are known which comprise a glass or plastic tube in which is carried a swab, a portion of which remains exposed out of the tube, with a breakable ampoule or vial containing a medicament or other liquid product which is to be applied being inserted within the swab mass. The tube is capped at the end opposite the swab and the assembly is then enclosed in a separate sterile package to protect the exposed swab portion. Such assembly thus requires a special outer sterile wrapper and additionally some mode of securing the swab within the tube, as with adhesives.

SUMMARY OF THE PRESENT INVENTION

The present invention is concerned with a method for the inexpensive mass production of swab applicators suitable for a wide range of purposes including antiseptic as well as non-antiseptic use. In accordance with the present invention a continuous length of thermoplastic tubing is extruded over a continuous length, coherent resilient mass of an absorbent material, the composite or filled article being formed such that the tubing radially compresses the absorbent material to a certain degree to thereby hold the mass securely within the tubing. The filled extruded article is then sectioned into individual applicator lengths and a cup-shaped cap is inserted over one end of each individual applicator length, the applicator length being received only part way in the cap so that a void remains in the latter. Following this the cap is sealed to the applicator length in an encircling course around the outer surface of the applicator length to provide at least a fluid-tight seal of the cap with the latter. The mass of resilient material filling the applicator length is then displaced bodily as with a plunger device or other means entering the uncapped end of the ap- jq plicator to move the mass so as to fill the void in the cap but in turn leave a void of substantially corresponding volume in the applicator length adjacent the open end thereof. A charge of liquid product such as a medicament, antiseptic or the like, is then injected into the length through the open end. The open 55 or other end of the length is then at least fluid-tightly sealed as with a plug or by deforming and heat sealing the plastic tubing at said other end. Removal of the closure cap preliminary to using the swab applicator can be accomplished by twisting the same relative to he applicator length to break its seal 60 therewith, and following such removal there is exposed a length of the absorbent material which serves as the swab tip during use.

In accordance with the present invention, the absorbent material can be one of several types suited for the intended 65 purpose included but not limited to a tow of fibrous material such a rayon, cotton, cellulose acetate, a natural or synthetic sponge material, e.g., an open cell reticulated foam material of a synthetic resin, and the like. The important characteristics of such material, of course, would be that it would have good ab- 70 sorption quality to hold the liquid product, would be compressible to a certain degree and be pervious to liquid flow therethrough.

The character of the fluid-tight seal of the cup-shaped closure cap to the applicator length of course will depend on the intended use of the swab. Thus for a surgical swab, the cap desirably should be completely hermetically sealed to the applicator length. Additionally, a surgical swab also could be sterilized after final sealing in known manner employing 5 known sterilizing techniques.

Further economy in the production of the swab applicator provided by the present invention can be realized by making the swab applicator as a single component device. In making such embodiment of the swab applicator, an individual applicator length has the mass of resilient material filling the length thereof longitudinally compressed inwardly from both ends thereof, leaving voids adjacent each end. The tubing or sheath is then flattened at one end to bring opposed side porJ5 tions of the end part into contact and they are heat sealed together to form a fluid-tight seal at said one end. A charge of liquid product is introduced into the applicator through the open other end. Such other end is then heat sealed in the same manner as the first end. A removable cap portion is then 2Q formed in the sheath by providing a frangible or weakened section in the sheath wall to permit ready separation of the sheath into two parts and thereby exposing a portion of the length of compressed absorbent material which can serve as a swab tip.

Other modifications in the construction of the swab applicator and the method of making the same will of course be possible depending on the particular use of the swab applicator. For example, various types of liquid product may be used such as nail polish, shoe polish, marking inks and the like. Also de30 pending on the use the amount of swab tip of absorbent material made available for use on removal of the closure cap can vary, the closure cap length varying in a corresponding manner.

BRIEF DESCRIPTION OF THE DRAWINGS

A fuller understanding of the nature and objects of the present invention will be had from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a swab applicator made in accordance with the principles of the present invention.

FIG. 2 is a sectional view illustrating the condition of the swab applicator shown in FIG. 1 following removal of the cap therefrom preliminary to use, the applicator being positioned upright to facilitate outflow of liquid product through the absorbent material.

FIG. 3 is a side view, partly in section of a modified form of swab applicator.

FIG. 4 is a side view of the swab applicator shown in FIG. 3 after removal of the cap therefrom.

FIG. 5 is a fragmentary sectional view illustrating an alternative mode of capping the swab tip end of the swab applicator shown in FIGS. 3 and 4.

FIG. 6 illustrates extrusion apparatus with which a continuous stock of swab applicator material can be made.

FIG. 7 is a schematic view of the processing steps involved in making a swab applicator in accordance with the present invention.

FIG. 8 shown a further form of swab applicator made in accordance with the principles of the present invention.

FIG. 9 is a longitudinal sectional view of still a further form of swab applicator made most economically as a single component device.

Throughout the following description like reference numerals are used to denote like parts in the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The swab applicator of the present invention is described herein in representative embodiment form as used for a surgical swab. As will be indicated at greater length herein, such device desirably is made under sterile manufacturing condi75 tions involving provision of sterile components, use of sterile

3,661,666 manufacturing machinery and maintainence of sterile manufacturing environment. If such sterile manufacturing is not possible, the swab applicators can be sterilized following the making of the same and employing known sterilizing procedures for this purpose. It will be understood that the present invention, however, is not limited to making surgical swabs only as it is equally applicable for the manufacture of other types of swab applicators employed normally in conjunction with application of shoe polish, nail polish, metal polish, cosmetics, paint, ink, insect repellant and the like. The swab applicator of the present invention is intended primarily as a one-time use item being discarded immediately after such first use, and for this reason it embodies she characteristics of being inexpensive and easy to make.

FIG. 1 illustrates one form of swab applicator 10 which is comprised on an easily resiliently deformable thermoplastic tube or sheath 12 which is filled with a resilient mass of an absorbent, fluid pervious material filler 14, the filler extending outwardly from one end of the sheath 12 so as to fill an end Closure cap 16 sealed to the sheath as at 18, the cap 16 having any convenient form such as being cup-shaped. The filler 14 confined within the sheath 12 is retained therein under a certain degree of radial compression which condition holds the filler mass within the sheath without resort to adhesively fixing 25 the former to the latter. The other end of the swab applicator is closed with a plug 20 which, similar to the cap 16, is sealed to the sheath as at 22. Intervening the plug 20 and the mass of absorbent material 14 is a void 24 extending along a short _a___________r________________________________{__} length^of the applicator and intended to serve as a receiving 30 and a void of substantially corresponding volume is created in ’ c i * , ... the applicator length adjacent said open end. Following withdrawal of the piston unit from applicator length 12, the applicator length with attached cap is advanced for a further processing station at which liquid product 25 is introduced degree on the mass of absorbent material 14. During passage through cooling chamber 40, the continuous filled article is cooled. Upon exit from the cooling chamber 40, the cooled composite article is delivered to a cutter unit 42 (FIG. 7) with which the continuous article is sectioned into individual swab applicator lengths 12, the individual applicator lengths 12 then being carried by conveyor 46 to the forming apparatus shown schematically in FIG. 7 for further processing in actually assembling the swab applicators 10. At the first station in the processing line, a cap 16 of suitable predetermined dimension is placed over the applicator length 12 in the manner indicated, suitable cap inserting apparatus 50 being employed for that purpose. As was indicated earlier, applicator length 12 is received only part way in cap 16 to leave a void in the cap. Following the insertion of the cap 16 on the applicator length 12, the cap is sealed to the applicator length 12 in an encircling, continuous course as at 18 employing for that purpose suitable sealing means, e.g., a heating iron unit 52. It will be understood, of course, that other sealing means including adhesive applicator, sonic fusion, etc. could be used as long as at least a fluid-tight seal of the cap to the applicator length is achieved. If the swab applicator is to be a surgical swab unit, a seal of a hermetic character is preferred. Following the sealing of the cap 16 to the applicator length at one end thereof, it passes on to a second station at which a piston unit 54 is employed to displace bodily, the mass of absorbent material 14 from the uncapped or open end of the applicator length until a portion of the mass fills the void in the cap 16 space for deposit into the applicator swab immediately prior to fixing plug 20 thereto of a quantity of liquid product 25. It will be discerned that following deposit of the product 25 in void 24, some of the liquid will migrate to the absorbent _{t a}__________ ________ ___ ________ material 14 and be retained absorpently therein as shown. The 35 into the applicator length through the open end thereof, such liquid product being injected or otherwise supplied to the applicator length with a suitable device such as injector pump 56. At the last processing station, the open end of the applicator is closed and provided with at least a fluid-tight seal. To the sheath to break the seal 18. With removal of the cap 16, a substantial portion of the absorbent material, viz., the portion extending beyond the end of sheath 12 is exposed to serve as a swabbing means in the manner illustrated in FIG. 2. By inverting the applicator to the position shown in FIG. 2, the liquid product 25 flows downwardly into and through the absorbent material and wets the exposed tip end of the absorbent material for ready transfer to the object being swabbed as, for example, the skin areas adjacent a cut or abrasion in human skin which are to be cleaned with an antiseptic. The resilience of the absorbent material 14 as well as the thickness and resilience of the sheath 12 provide that the structure of the swab as a whole can be squeezed to facilitate and accelerate passage of the liquid product through the absorbent material to the exposed tip end of the latter.

In making the swab applicator 10, the apparatus and procedures illustrated in FIGS. 6 and 7 can be employed. With continuing reference to these FIGURES it will be noted that as a first step a continuous length stock of absorbent material 14 is fed through a collecting horn 26 into the center of a crosshead-type extrusion unit 30 into which is also supplied a flow of molten thermoplastic material 32. Such extrusion device and method of extruding a filled plastic tube advantageously may be the same as those described in pending U.S. Application Ser. No. 747,279 filed July 24, 1968, now U.S. Pat. No. 3,579,623. As will be noted, the thermoplastic issues in tacky or plastic state from the extruder unit 30 as a continuous length of tubing 35 encircling the continuous length of absorbent material 14. The tubing 35 on exit from unit 30 has a greater diameter than the final product but it is pulled down to final size upon entering cooling chamber 40. Such pull down of the plastic tubing reduces its wall thickness to provide a product which is squeezably deformable and also results in the tubing effective a radial compression of a certain liquid product is thus retained within the swab available for immediate application when the applicator swab is opened. The swab applicator is made ready for use by removing the cap 16 from the sheath 12 which can be accomplished in vari- _____ _ .............................

ous ways including a rotary twisting of the cap while holding 40 that end, a plug 20 is inserted on the applicator length” in the ♦ ma 1*™λ — ·t. — _ 1 4 0 XX/1»1- - *____. — x z* λx « __ _ - · , manner shown utilizing a suitable plug inserting device 58. A heat sealing unit 60 is then used to seal the plug to the applicator length. During the heat sealing of the plug 20 and cap 16 to the applicator length 12, the latter can be rotated about its own axis to facilitate such sealing.

As shown in FIG. 3 certain modifications in the construction of the swab applicator are possible. For example, the swab applicator 100 includes a plastic sheath 102 covering an absorbent material mass 104 which is provided as a reticulated foam of a synthetic resin, the material being a sponge-like mass pervious to liquid flow and having good characteristics of resilience and softness. The absorbent material 104 fills the sheath 102 and closure cap 106 in the same manner as that previously described with respect to the swab applicator shown in FIG. 1. It will be understood that the sheath 102 and filler 104 are extruded as a continuous length composite structure in the same manner as previously described and shown in FIG. 6. In this construction it will be noted that in lieu of employing a plug to close off the uncapped end of the swab, the thermoplastic material of the sheath itself can be flattened so as to bring opposed side portions of the wall thereof into contact with each other and then heat seal them together to form the type of the end seal illustrated at 108 in FIG. 3. To facilitate removal of the closure cap 106 for exposing a swab tip when using the swab applicator, the outer surface of the cap 106 may be knurled as at 112 to provide a positive gripping surface for the user when twisting the cap free from the applicator length. With the removal of the cap 106, the absorbent reticulated foam material 104 is exposed as shown in FIG. 4 to provide a swab tip which expands to a certain degree upon release of the encircling cap structure and the liquid product 114 can be squeezed through the mass of material 104 and from the void 116 at the opposite end of the swab applicator to the exposed applicator tip.

3,661,666

FIG. 5 illustrates a modification to the swab applicator of FIGS. 3 and 4 wherein the cap member 120 instead of being provided as a cup-shaped member could be provided as a short length of tubing and being sealed at its outer end in the same manner of providing heat-sealed closure 108 illustrated 5 in FIG. 3.

FIG. 8 shows a further form of swab structure in which in lieu of an end closure cap member in which is received the applicator length as shown in FIGS. 1 and 3, the extruded sheath 150 in which is enclosed the absorbent material 152 is itself ¹⁰modified to provide a removable cap structure thereon. To provide this the sheath along an encircling course is provided with a frangible or weakened section 154 which while strong enough to retain the absorbent material therein prior to use is j insufficient to withstand moderate rotative twisting of portion ¹156 with respect to the remainder of the sheath and such portion 156 thus will tear loose and be pulled from its enclosing position about a length of the absorbent material 152. The thus exposed length of absorbent material constitutes a swab 20 tip. It will be seen then that in distinction with the earlierdescribed embodiments, no void is left in the applicator structure during manufacture thereof and the liquid product 158 is injected directly into the absorbent material before sealing off the ends of the swab body with the closure plugs 160. 25

Most economical and simple manufacture of the swab applicator can be achieved by making the applicator as a single component device, i.e., a device comprised of the sectioned, filled tubular article alone. Such a device 200 is illustrated in FIG. 9 from which it will be noted the device consists of a tu- ³⁰bular sheath 202 enclosing a mass of absorbent material or filler 204 and constituted of a length of the extruded, filled article described earlier herein. The article includes heat-sealed ends as at 206 and 208 respectively, and a pair of voids 210 and 212, with the latter serving as a reservoir for liquid product 214. The sheath 202 is provided with a frangible section as at 216 which permits ready separation of the sheath into two parts to allow exposing a portion of the filler 204 as at 220 which serves as a swab tip. In making the swab applicator ₄q 200, an individual applicator length of the tubular filled article has its mass of filler material 204 compressed longitudinally inwardly from both ends to thereby provide the voids 210, 212. One end 206 is then heat sealed to provide a fluid-tight seal, such heat sealing being in the same manner as that shown 45 at 108 in FIG. 3. Liquid product 212 is then introduced into void 214 and the other end 208 is heat-sealed shut to provide a fluid-tight seal. A removable cap portion is then formed on the sheath 202 by providing frangible section 216 therein.

As was indicated earlier if the swab applicator of the present 50 invention is intended for use as a surgical swab and it is not manufactured under sterile conditions, the swab applicator after it has been completely manufactured can be sterilized using known sterilizing apparatus and techniques. Thus, for example, as shown in FIG. 1 the swab applicator can be provided with small apertures indicated at 19 at opposite ends thereof, such apertures passing through in this case the closure cap 16 and the plastic sheath 12 to provide access and egress for a sterilizing gas or liquid such as one containing ethylene gQ oxide. Upon completion of the sterilizing operation the apertures 19 can be sealed in known manner. Thus, the swab applicator interior is and remains sterile until used. The mode of exposing the swab tip by twistingly removing the closure cap 16 ensures avoidance of contamination of the swab tip. ¢5