US 2371900 A
Description (OCR text may contain errors)
F. W. LIVERMONT CLOSURE CAP March 20, 1945.
Filed March 9, 1942 Patented Mar. 20, 1945 f unison onosonn'ourf Eran]; w. Livemont, Glendale; callifi ginssignor by direct. aml mesne. assignments, to Tubing Seal-(781),.Il1m, Los Angeles, Cblifgs corpora,-
tion of California.
Amplicatiom Max:119, 194e, No; sass-4r soia ms. (o1; zed-42w.
This invention relates to closure caps. for tub.- i'ngt, and the. like, and parti'cularlyt'o friction caps for smooth-ended tubing as distinct from caps 'for tubes having threads or other special devices for looking with the cap.
A broad object of the invention is to providea simple, inexpensive and easily manipulated fric tioncap; t
Another object is to provizfe a. cap 'capuble'oi fi-rmly, frictionetl'ly engaging a; smooth without marring or defacing" the tubing. and witlroutv danger of the can being accidentally sucked or forced into the tubing. 7
In certain industries; such as the airplane manufacturing industry, largeanrount's of soft meta-1 tubing,- such as aluminum tubing, are em p'l'oyed for pressure linesand' conduits.- It isvery important that this: tubing, which is clean at the time or manufacture, be protected against the entry of dust or foreign matter between the time it leaves the tube department and the timeit is completely installed. It he been the practice. therefore, toprovide some sort of temporary closure forthe open ends of all tubing while ibis being transported and i'z-istslled. some mun-gee p'roviefed with:- thr ead-ed ends, or-withspecia-r con masters; and various types of caps have been developed for keeping dirt out of such tubing.
However, a large amount of tubing used has plain, smooth ends to which it is more cfifilcu'lt to attach a closure member; In .fact the only closure members that have heretofore been commerci'ally used on smooth-enclecl tubing, are rub ber' plugs. caps, and cellulose film. l Such devices, however, have the serious objection that" they are sometimes drawninto the tubing by suction appliedtheretoduring installation, and remainyi-n the tubing to cause trouble later on, orare fragile to the extent of offering no protection against damage to the ends of tubing.
In accordance with the present inventionl provide a closure cap capable of being firmlyattached. to ssmooth-ended tube by a metallic coil spring side wall that presses firmly against the tubes during ban and instalh tube and retainsan-emi'member againstthe open end of the tube. device is free from'thc mentioned defect of rubber caps, plugs, and eerl'ulose film without having any serious new ob jectionable features. It has'the further advantage over rubber caps,- and cellulose film of of fording better mechanical proteotion'to theouter surface of thetubing i Other objects ancl'features 01E thewi-nvention will. appear from the detailed: description to folvention illustrated in the drawing. In the drawing;
low .of certain oreferred' embodiments of'the 'Fig, 1.15- a jview partly in elevation and partlyin secfiionjof one embodiment, of the cap, in ac; corflgnce with my inventioml y '2 'is aysecti'onal view,"s howi'ng the-cap of ro er attached toatube; 3' i-Figyii' is a: plan View of the cap shown inFig"; '1'; Figt i is a; side elevation viewof an altemative construction inaccordance with the invention, in process of manufacture; w
'Fig'. 51's as side elevationw'" a; portion" broken away, of .thedevice shown in Fig; 4, when menufeature is completed:
P Fig. Skis asideel'evation of a; third corriance-with the invention; and v v I Fig; 7 is-e: sectional view offs; foumth oaapin aice'ordance with the-invention, shown attachetl to a tube. l 1
Referring; fi1'st', -to Fig. i, thecap therein disclosed comprises an closely coileei spring wire coil I?! of roughly cylindrical shape containing therew-i-thin a: constrained can l t, the latter being positioned! within theupper end of the coil I! with itsopenside clown. upperturn II of the coil is extended i nwardiy against the top wall of the cup L es can in'ac showrr irrF ig. 3 to-fpreventthe cup from being forcetl'upwordly out-"oi the coil; The cylindricali Wfiiflblf the cupis: also firmly gripped. bythe upper fitted turns of the coil Nb Imm edialtely-belowthe open edge hior the cup I I the turns Of EIIE-CGiT eonstri ct to at smaller oztorneter and. then expand to a larger diameter toward the: lower openend ofthe cap.' w The internal diameter of the/cuptl is slightly Iarg'er than the. external diameter of the. tubing on .vvh ich the cap. is. to be used, so that it wilt sIipireely over the end of the tubing. The. extent tol which the coil. is constricted below" the margin: M of the cup canvary according to the frictional grip desired.
When theinvention is usedrfor closing: the ends Iation to prevent therentry of dirt. ond'ust', .it is desireble'thatthe cap beeesily urtt:at'chrzblev and removable, In such. service, when employing a coil moi spring steel wire or M-gauge'for use in a; cap designed for, aluminum tubing 4 (.1501,
sometimes necessary to prevent any rubbing, frictional motion between the cap and tubing, and
under such conditions my cap is applied to the from a tube is less, so that there is no permanent deformation of the cap.
tubing by gripping the lower, large diameter turns between the fingers of one hand, gripping the, f
upper end of the cap with the fingers of the other hand, and relatively rotating the two ends of the There is shown in Fig. 6 a modification of the cap shown in Fig. 1. Whereas in Fig. l the coil I is wound in a continuous helix from one end to the other, the cap 30 of Fig. 6 consists of three helices rather than one continuous helix. Thus there is an upper helix 3!, which grips the cup 32 and is connected at its lower end by a vertically extending section 33 to the lower'end of amiddle helix 34, which is wound upwardly until its upper coil abuts against the lower coil of the upper helix 3|,
The uppermost turn of the middle helix 34 is connected by a downwardly extending section 35 to the upper turn of a lower helix 38. @Therelative internal diameters of the difin unwinding direction to pand the middle turns, including turn 15, to a diameter larger than the tubing, and slipping the cap into place on the tubing while it is so expanded.
- After the cap has been positioned on the tubing the lower end of the coil is stretched onto the tubing slightly before being released. This slightly separates the middle turns which grip the tubing 11, causing them to maintain the cup H against the open end of the tubing with a slight tension. This tension is increased as much as possibleby preloading the coil in the winding process. Methods of winding springs to preload them are, well-known in the spring manufacturing art. A particular advantage of preloading in the construction of Figs. 1 and 2 is that it enables the attainment of a substantial force holding the cup H against the end of the tubing 11 without employing alarge separation between adjacent turns of the coil 10. Large spacings between the turns is objectionable in that it facilitates the accumulation of dirt and foreign matter between the turns.
I have shownin-Fig. 4 a cap structure in accordance with the invention that can be completely formedfrom sheet metal. Thus a thin sheet metal cap of cup-shape having a fiat end 21 is formed integrally with a cylindrical side wall, which terminates at the open edge in an external bead 22. comprises three zones 23, 24 and 25. The end zones 23' and -are imperforate but may be roughened or knurled to facilitate finger engage- I ment therewith. The central zone 24 is perforated by a plurality of steeply helically extending slots 26, which slots divide the metal of zone 24 into a large number of helical strips floorresponding in function to the turns of the coil spring in Figs. 1 and 2.
The cap'shown in Fig. 4 is of slightly larger diameter than the tubing on which it is to be used. Prior to using the cap, it is distorted by twisting it into hourglass shape, as shown in Fig. 5. Twisting is accomplished by gripping the upper and lower knurled portions 23 and 25 with any suitable tool, or with the fingers, and relatively rotating them-in opposite directions.- The completed cap shown in Fig. 5 has a smaller internal diameter 'at its waist than the external diameter ofthe tubing On which it is to-be used. However, it can be applied to the tubing easily by relatively twisting the opposite ends of the cap in the same way as described with reference to Figs. 1 and 2. Of course during the forming of thecap of Fig. 5 the material was twisted beyond its elastic limits, so that it wa permanently distorted from the shape shown in Fig. 4; whereas the twist applied during application to or removal The cylindrical wall of the cap ferent portions of the coil may be the same as in the coil I0 01 Fig. l, and it can be applied toand removed from a tube by the same manipulatioll. An advantage of the construction shown in Fig. 6 is that a force tending to pull the cap off a tube tends to compress the turns of the middle helix 34-agains't each other instead of separating them, thereby increasing the holding ability of the cap.
.The three constructions so far described are adapted to lock against the exterior surface of the tubing. In a modification of the invention, thev gripping portion is inserted within the tubing, asshown in Fig. 7. In this construction the clo sure cap has an end wall 4| of diameter substantially equal to the external diameter of the tubing 42 with which the device is to be used, and
q merges into a short cylindrical section 43 of the same external diameter. At its lower edge the cylindrical section 43 extends inwardly, defining a flat annular shoulder 44 adapted to fit against the end of the tubing 42. The inner .edge of the shoulder 44 merges into the upper end of an inwardly tapered skirt 45 of smaller diameter than the internal diameter of thetubing 42.
The end wall 4|, the cylindrical section 43, and the shoulder 44 define an internal groove which receives the upper coil 46 of a spring r'etaining member 41, which extends inside the tubing 42 and engages therewith; The member 41 is of relativelysmall diameter within the skirt 45, but the coils become progressively larger below the skirt so that they bear against and frictionally engage the inner surface of the tubing for a length of. about four turns. in a zone 48. Below the zone 48, the coils become progressively smaller in diameter, to facilitate the entry of the device into the endof the tubing. In the particular embodiment shown in Fig. 7,, the end of the lowest coil is extended diametrically through an eye 49 formed in the lower end of a rod 50, which is extended axially up through the member 41 and through a snugly fittin hole in the end member 41. Beyond the member 4! the rod is bent to define a handle 5 I. The closure device shown in Fig. 7 can be read: ily placed in position by pressing the handle 5| downwardly relative to the closure cap 46. This elongates the'spring member 4? and contracts it radially, so that it can freely enter the tubing until theshoulder 44 engages against the end of the tubing. Thereafter the handle 51 is re leased permitting the spring member to contract longitudinally and expand radially into engagement with the tubing. The coils in the zone. will expand into engagement with the tubing before longitudinal contraction of the spring'memher is completed, thereby maintaining the shoulder 44 firmly against the end of the tubing.
It is also-possible to radially contract the spring member 41 for insertion of the device into the tubing by relatively rotating the handle 5! relative to the cap 40 in such direction as to tighten the spring. When the handle is released, the spring then expands to snugly engage the inner surface of the tubing.
It is also possible to insert the spring member 41 into the tubing by simply pressing on the cap 40, with or without a simultaneous rotary motion tending to screw the member 41 into the tubing. When the device is intended for insertion in this manner the rod 50 can be eliminated and the end coils of smooth plated spring wire so that there can be no scratching of the surface of the tubing even if the device is forced on and off the tubing, instead of being expanded (by relative rotation of the opposite ends) prior to attachment and removal.
Although the invention is particularly useful for closing the ends of tubing during transportation and installation, it is by no means limited to such uses, and it may be employed as a closure member or stopper for bottlesand other containers, if desired. When so used the neck of the bottle can, if desired, be provided with an annular corrugation or shoulder cooperating with the gripping portion of the cap to help hold the cap against removal.
1. A closure cap for covering and sealing the end of a tubular member, said cap comprising: an end section adapted to fit against and close the end of the tubular member, and a lower section connected at one end to the rim of said end section and adapted to enclose and grip the peripheral surface of the tubular member to retain said end section in position, said lower section consisting of helically extending resilient elements tapering in diameter from a large diameter at the open end thereof to a smaller diameter intermediate the ends, to form a gripping section having a portion of a diameter less than the diameter of the tubular member whereby the resilient elements making up the said portion of lesser diameter act to grip the peripheral surface of the tubular member to retain .the' closure cap in posi-- tion.
2. A closure cap as described in claim 1, in which said lower member is of larger internal diameter than the external diameter of said tubular member at its open end and is normally of smaller internal diameter at its midportion than the external diameter of the tubular member. i I
3. A sheet metal cap comprising: a circular end wall connected at its rim to an approximately cylindrical wall,-in which a portion of said cylindrical wall is divided by helical slots into radially yieldable helical strips, and said portion varies in diameter from a large diameter at its ends to a smaller diameter at its mid portion.
FRANK W. LIVERMONT.