US 2211975 A
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Au .2o,194o. m. HENbiRIcKsdN 3 ,211,975
CATHETER Filed March 16, 1937 Raienied Aug. 20, 1940 UNITED STATES PATENT OFFICE CATHETER Floyd 0. Hendrickson, Canton, Ohio Application March 1 6, 1937, Serial No. 131,125
This invention relates to catheters and similar tubular appliances for surgical or other uses, and has for its principal objects the provision of a superior catheter construction providing maximum.interior diameter or cross-sectional area with minimum wall thickness and minimum outside diameter together with desira le transverse rigidity to resist collapse and also a certain amount of longitudinal rigidity, especially in the tip of the catheter, to facilitate insertion of the frequently rather long and slender catheter into a restricted tubular passage such as a male urethra, and generally to provide economy and efliciency in catheter constructions.
The manner in which these and other objects of the invention are attained w ll appear from the following description of the invention in which reference will be had to the accompanying drawing of which Fig. 1 is an elevation, partially broken away for clarity of illustration, showing a catheter embodying the principles of the present invention;
Fig. 2 is a sectional elevation, on an enlarged scale, illustrating more clearly constructional details of the tip portion of the catheter of Fig. 1.
Fig. 3 is a vertical section taken on line 3-3 of Fig. l.
For purposes of illustration, I have shown my invention in a preferred form embodied in a urethral catheter comprising a relatively long and slender thin-walled rubber tube l having a closed tip end H and an enlarged open end l2 adjacent which the rubber wall of the tube is made considerably heavier for a short distance to provide a tube-gripping connector portion l3. Drainage openings l4, H are provided in the tube wall, preferably in diametrically opposed positions, adjacent the tip end ll of the tube i0. Embedded wholly within the wall of the thinwalled tubular portion of the catheter and extending substantially from the end of the tubegripping connection portion l3 to a point a short distance from the drainage openings l4, I4, is provided a reenforcing coil l5 of, for example, spring steel wire providing a high degree of transverse rigidity and effectively preventing collapse of the tube, which in prior devices often occurs as a result of bending or other collapsing pressure while in use, and also imparting to the catheter a considerable amount of longitudinal rigidity without however destroying its flexibility..
For imparting greater longitudinal rigidity to the tip of the catheter into which the wire coil 15 does not extend and which is weakened considerably by the cut-out drainage apertures, a
the ends of the two legs of the U.
To provide additional rigidity in the catheter tip, and especially to provide resistance to puncture by the sound or stylet customarily used for facilitating insertion of the" catheter, the rubber wall at the tip and adjacent areas, preferably at least as far as the end of the wire coil l5, may be made heavier and thicker as more clearly shown in Fig. 2, to provide a wall say about twice as thick as the wall of the tube proper.
For ordinary catheters, the coil wire reenforcing element l5 and-the U shaped tip reenforcing element l6 may be formed of stainless steel wire of about 0.007 inch gauge, the coil preferably having a low pitch, for example 20 Cells to the inch. With such a reenforcing ele- 'ment, an overall catheter wall thickness of as low as 0.03 to 0.05 inch is regularly used and has been found to be entirely reliable and wholly satisfactory. Substantial advantages are noted even with walls as thick as 0.10 inch. Such a slight wall thickness of course insures maximum fluid capacity within the catheter for any permissible outside diameter, or from a different point of view, permits substantial reduction in the outside diameter of the catheter with lessened pain and discomfort to the patient, but
without reduction of fluid capacity. Considerable variation in the character and dimensions of the reenforcing elements and in the overall wall thickness of course are contemplated in catheters for various uses. Whereas ordinary soft-rubber catheters having walls as thin as those of the present catheter would have practically no transverse rigidity, the catheter of the present invention positively resists collapse while in use, even when doubled upon itself, but is nevertheless freely flexible for ready insertion through tortuous body passages, such insertion being greatly facilitated by the substantial longitudinal stiffness of the catheter, and
especially, by the reenforced tip.
The integral tube-gripping connector portion l3 permits convenient coupling of the catheter to do so.
The rubber embodied in thecatheters of the present invention may be caoutchouc, gutta percha, balata, or similar natural or synthetic more less rubbery materials including suchsynthetic materials as plasticized polymerized Vinyl chloride, polymerized chloroprene known as neoprene, and the like,,but preferably is unmasticated latex rubber deposited directly from natural rubber latex which of course may be suitably pre-conditioned for use according to known processes. Such unmasticated latex rubber is ,especially resistant to the repeated sterilizations to which a surgical appliance must be subjected, is sufliciently tough and strong to withstand rough usage, and, more particularly, is well adapted to form a cohesive coating com pletely embedding and firmly holding the metallic wire reenforcing elements utilized in the present invention.
Numerous modifications and variations may be made in the invention as herein described with- I claim:
1. A catheter or similar appliance comprising a relatively long and slender tubular portion having a relatively thin rubber wall, a closed tip thereon having a relatively thicker rubber wall provided with a transverse aperture, a helical wire reenforcing element embedded within the relatively thin wall of the tubular portion and extending through a substantial length of said tubular portion and providing transverse rigidity therefor, the successive convolutions of the helical reenioncing element being definitely spaced apart, and a U shaped wire reenforcing element embedded within the relatively heavier wall of the tip providing longitudinal rigidity therefor, all of said rubber being unmasticated latex rubber having the properties of rubber deposited directly irom rubber latex.
2. A catheter or similar appliance as defined in claim 1 in which the legs of the U shaped reenforcing element extend to and are positively engaged with the helical wire reenforcing element.
FLOYD C. HENDRICKSON.