Field of Search:
15/104.94,208--210,231 401/126,130,196,198,202,207 128/269,356,357 15/143
Description:
BACKGROUND OF THE INVENTION
Conventional swabs known in the art consist of a wooden applicator stick with a wad of fibrous material, usually cotton, secured to one or both ends of the stick.
These swabs perform their function adequately under normal circumstances, however, when they are used, for example, in a clean room atmosphere, common with the aerospace industries, a number of problems arise.
Many rocket engine components are highly delicate in nature requiring meticulous care in assembling and cleaning to prevent malfunction of the part. Therefore, it is necessary that they be assembled in a clean room which is virtually dust free and temperature controlled thereby creating an atmosphere which complies with rigid standards. Cotton swabs are commonly used in this atmosphere to clean contaminating particles and solvents from components after they have gone through a machining and flushing operation. Conventional swabs, while they possess good absorbent qualities, tend to leave a residue of particles both from the cotton wad and the wooden applicator stick when they are employed. Many components, for example valves and injector assemblies, have many, very small orifices and ports which are easily clogged. Hence, while removing metal chips and solvents from components with conventional swabs, the swabs snag on threaded parts or rough edges and became a source of contamination. In addition, when cleaning larger interconnected assemblies, for example, rocket engines and turbo pumps, conventional swabs have been known to break causing the loose broken end to drop into the assembly, thus necessitating a costly disassembly operations to remove the offending particle.
It is an object of this invention to provide a noncontaminating swab suited for a clean room application. More particularly, it is an object of this invention to provide a noncontaminating applicator with an absorbent end covered with a netted envelop thereby preventing egress of absorbent material through the protective covering.
SUMMARY OF THE INVENTION
The invention comprises an applicator handle with at least one end having a wad of fibrous absorbent material attached which is surrounded and entrapped by an envelop of woven or otherwise porous fabric. The fabric is sealed at one end, slipped over the absorbent material and secured to the handle below the base of the absorbent material by, for example, a length of heat shrinkable polymeric material.
When a wooden handle is utilized the heat shrinkable polymeric material used to secure the fabric over the fibrous absorbent material is preferably extended down the entire length of the handle thereby strengthening the handle rendering it almost unbreakable while, at the same time, preventing wooden particles from abrading off into a workpiece during cleaning operations.
The handle of the applicator may be a solid nylon rod with a nylon envelop covering the absorbent material. The base of the envelop is then fused to the handle, thereby entrapping the absorbent wad.
An advantage over the prior art is realized in that the fibers or strands from the absorbent material are retained or entrapped within a woven fabric covering thus preventing any possibility of further contamination of the part being cleaned.
A further advantage is realized over the prior art in that the wooden handle is protected from breakage and abrasion by extending the heat shrinkable synthetic polymeric material, used to lock the fabric envelop to the handle, down the entire length of the handle.
DESCRIPTION OF THE DRAWINGS
The above noted objects and further advantages of the present invention will be more fully understood upon the study of the following detailed description in conjunction with the detailed drawings in which:
FIG. 1 is a perspective view of one version of the present invention,
FIG. 2 is a perspective view of a preferred embodiment of the invention,
FIG. 3 is a perspective view of the noncontaminating applicator stick illustrating an absorbent material at both ends of the handle,
FIG. 4 is an exploded view of the various parts of the instant invention;
FIG. 5 is a partially cutaway section of the assembled applicator, and,
FIG. 6 is a partially sectioned view of another embodiment of the present invention.
Referring now to FIG. 1, an applicator swab generally designated as 10 comprises a handle 12, with an absorbent end 14, which is surrounded or enveloped by a porous polymeric woven fabric 16 attached at its base 20 (FIG. 4) to the handle by a length of heat shrinkable polymeric material 22. The end 24 of material 22 shrinks, firmly locking absorbent wad 14 and fabric 16 to handle 12 when heated. The porous woven fabric can be applied around the absorbent wad in a number of ways. For example, a square piece of fabric can be gathered together over wad 14 forming base 20 or the fabric may be folded over and stitched up both sides, thus forming the envelop. Another example may be to use a tubular woven fabric, stitch an end thereof followed by turning the resultant envelop inside out placing the stitched end inside the envelop. Still another example would be to knit the fabric thereby forming the desired shape of envelop 16.
FIG. 2 differs from FIG. 1 in that the heat shrinkable material 22, while primarily locking envelop 16, around the wad 14 to the handle, extends to the end of the handle thereby protecting and strengthening the swab 10. If the handle 12 is wood it can be quite easily broken thus it needs strengthening. In addition, wood chips are a source of contaminants as previously pointed out, and by covering the entire handle, both problems are solved.
Referring to FIG. 3, an alternate swab is illustrated consisting of a double-ended applicator having absorbent material 14, 14' at its ends covered by a porous protective envelop 16, 16' secured to handle 12 by heat shrinkable sheaths 22, 22'.
FIG. 4 is an exploded view of the applicator 10 as shown in FIG. 1. Absorbent material 14, for example cotton, is wound or otherwise attached by known processes to end 13 of handle 12. An envelop 16, for example, braided nylon, having a closed end 18 and an open end or base 20 is slipped over absorbent material 14. The length of envelop 16 is sufficiently long to extend beyond the base 15 of the absorbent material 14. A length of heat shrinkable synthetic polymeric material 22 such as irradiated polyolifin or polyethylene having a diameter approximately twice that of handle 12 is subsequently slipped over the handle in a direction towards the absorbent material. End 24 of sheath 22 overlaps both the base portion 15 of wad 14 and base 20 of envelop 16. The heat shrinkable material is of sufficient length to both anchor the wad 14 and the envelop 16 while at the same time tightly adhering to a portion of handle 12 as indicated in FIG. 5 when heat is applied to the polymeric material 22 thereby shrinking it in place. Obviously, the sheath 22 could be extended the entire length of handle 12 as previously pointed out and shown in FIG. 2.
FIG. 6 is an alternate embodiment wherein the handle 32 and the envelop 36 are made of the same material for example, handle 32 is of solid nylon while envelop 36 is a braided nylon. To attach the absorbent material 34 to the end 33 of handle 32 the envelop 36 is slipped over wad 34 and heat fused at point 38 of the handle. Another feature of the invention resides in the use of different materials for example, the handle could be a polypropylene plastic while the envelop is braided nylon. Other woven or porous plastic materials or woven natural fibers may be employed in constructing the envelop.
The mesh size or the diameter of the interstices defined by the porous polymeric envelop 16 and 36 of the present invention is a size sufficient to prevent egress of fibrous material 14 and 34 through the interstices while at the same time allowing ingress of fluids to be absorbed by the wad of fibrous absorbent 14 and 34.
In operation, the noncontaminating swabs lend themselves to a variety of cleaning operations necessary during fabrication or processing of aerospace hardware while in a clean room atmosphere.
The following cleaning solvents are compatible with the preferred embodiment of the invention wherein a braided nylon envelop surrounds a cotton wad and is locked in place by a length of heat shrinkable tubing, for example, a polyolefin heat shrinkable irradiated tubing of the type manufactured by Raychem Corporation and sold under the registered trademark Thermofit RNF-100; trichlorethylene, trichlortrifluoroethane, alkaline cleaner, carbon tetrachloride and alcohol.
In addition, the swabs of the present invention can be cleaned and used over again since the protective porous covering retains the integrity of the fibrous wadding.
Although the invention has been described in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of this invention being limited only by the terms of the appended claims.