US2580991A - Guide tube - Google Patents

Description

v UH; III 7"""l I. I 7 5 a Jan. 1, 1952 L. BARRETT GUIDE TUBE Filed April 2. 1949 INVENTOR. LEQN BARRETT \\\\\krlllll= ATTORNEY Patented Jan. 1, 1 952 UNITED STATE GUIDE TUB Leon Barrett, Philadelphia, Pa.-',-' ass'ignor to Quick-Change Carriers,

Pennsylvania Inc., a corporation of Application April 2, 1949, Serial No. 85,169

Claims. 1

:My'invention relates to guide tubes, and it rei lates'more' particularly to flexible guide tubes, such; for'instance, as are used in carriers for full fashioned hosiery knitting machines.

.In the hosiery knitting art, the use of flexible guide tubes on carriers has proven of considerable merit; for among other advantages it per mits harmless deflection of the yarn guide tube in all cases of undesired contact with an inadvertently dislodged sinker or other portion of the knitting apparatus. Suitable flexible guide tubes have been diificult to provide, however. Thus, in cases where a flexible guide tube comprises a helix formed of ordinary round wire, givingmerely a line contact between adjacent convolutions, the jarring of the carrier at the end of each course-laying stroke may tend to cause vibration in the guide tube, resulting in undesired variation in the paying out of the yarn. Moreover, by the use of such wire, the flexibility is more or less uncontrolled and again variation in the paying out of the yarn may result.

On the other hand, flexible guide tubes comprising a helix made of a usual form of flat ribbon wire, while tending to be more rigid, may still prove of less than optimum satisfaction, for when deflection occurs, the spiral may open and receive a portion of the yarn, and pinch said yarn on closing. In order to avoid this difiiculty, flexible guide tubes have been invented, whereby alternate helices of flat and round wire are used. Such guide tubes result in greater flexibility and a lessening of the tendency to pinch the yarn between adjacent coils. Nevertheless, they-are diflicult to make, and on occasion have been known to become dislodged so as tofail properly to return from their deflected position.

It is an object of my invention therefore, to provide a flexible guide tube which will safely deflect upon undesired contact with an object in the path of its travel, and which will immediately return to its original position upon being freed from said object, without pinching or cutting the yarn or other substance being guided therethrough.

Another object of my invention is to provide a flexible guide tube so constructed as to dampen any tendency to vibrate when its carrier is struck, as for instance, when it impinges against a limiting stop at the end of its course-laying stroke.

A further object of my invention is to provide a flexible guide tube which is simple and inexpensive to manufacture, safe in use, easy to install and remove, is wear-resistant and which will be'of minimum thickness at its discharge end.

Other objects will beapparent from the de- 3 reference characters indicate like parts:

tionship of parts and yarn during the recoiling scription and claims which follow, as well as from-an examination of the drawings. With the above and other objects in view, my invention consists of a flexible guide tube comprising a substantially flat ribbon having a chamfered edge, and formed into a helix with the chamfered edge of one convolution substantially juxtaposed to an edge of the next convolution; an inlet conduit-disposed at the inlet portion of said flexible guide tube; and an outlet conduit disposed at the outlet portion of said flexible guide tube; said inlet conduit comprising a shoulder adapted to cover the inlet terminus of said ribbon; and said outlet conduit comprising a shoulder adapted to cover the outlet terminus of said ribbon, and also comprising a channel extendingfrom the-interior of said helix to an outlet port substantially beyond said outlet terminus; the external diameter of said conduit adjacent said outlet port being substantially less than theexternal diameter of said helix; and said inlet and outlet conduits being in spaced relation to each other. 7 For the purpose of illustrating myinvention, I have shown in the accompanying drawings form's thereof which are at present preferred by me, since the same have been found in practice to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which my invention consists can be variously arranged and organized and that my invention is not limited to the precise arrangements and: organizations of the instrumentalities; asherein shown and described.

Referring now to the drawings, in which like t Figure 1 represents a perspective vview of a full-fashioned hosiery knitting machine carrier holding-a'flexible guide tube embodying my invention. p

Figure 2 represents an enlarged, vertical sectional view of, a flexible guide tube embodying myinvention, showing the same in mounted relation to the yarn guide tube-holding end of the carrier shown .in Figure 1.

Figure'3 represents a sectional view taken generally :along. thelines 3.3 of Figure 2.

. Figureirepresents a fragmentary sectional view. of a; portion of a flexible guide tube embodying my invention, showing the same in fully deflected condition during yarn-guiding operation. Figure 5 represents a fragmentary sectional view or the same portion of flexible guide tube as illustrated in Figure 4, but showing the relaoperation afterrelease from deflection.

Figure 6 represents a fragmentary sectional view of jjthe same portion of flexible guide tube as illustrated in Figures 4 and 5, but showing the flexible guide tube of my invention, in conjunction with a full-fashioned hosiery knitting machine carrier, although it is to be understood that it is not limited thereto, and is-oapable for use with other machines or other carriers, as well as for guiding other materials than yarn, without departing from the spirit. or essential attributes of my invention.

Thus, according to my invention, I provide-a flexible guide tube ID adapted to be carried, substantially at one end H thereof, byacarrier [2 having jaws I3 and I4 adapted yieldably to grip said end H .of said flexible'guide tube .IB. The carrier 12 comprises an upper base portion I5 adapted to be secured to a suitable portion of the knitting machine ,(not shown) A suitable yarn guide channel [6 may be formed along the upper face H of the carrier i2, operablyto lead theyarn l8 therealong andinto proper position for entrance into the inlet portion I9 .of the yarn uide tube [0.

The yarn guide tube .10 preferably comprises a steel ribbon wire 29 formed about a helix with a single ribbon forming adjacent convolutions. The cross section of said ribbon wire is Preferably polygonal, .and in a desired form of my invention comprises substantially a rectangle with one .corner 2| thereof chamfered; and said chamfered corner being adjacent an edge 22 and an internal .face 23 of the convolution 24. The external face 25 of the polygon may besubstantialy parallelv to the internal face 23, and the unchamfered edge 26 is preferablyperpendicular to the external face. .25, .and parallel to the edge 22.

It will thus be foundthat successive convolutions .24, 21, 28 and .29, etc. formed .of .ribbonof the cross-section described, provide a tube of substantially smoothly continuous exterior 3.0.

.and substantially interrupted interior .3l, while I the adjacent convolutions .24, 21,. 28, .etc. bear against one another along a respective .areacontact :32, .33, 34, etc. The .effect in operation, of this construction :will be more .fully described hereinafter.

An inlet .conduit .35 .isprefera-bly the inlet endof .theguide :tube lll and :comprises a mandrel 36.1:aVing-aneXt8rnal diameter substantially equal .to .the .internal diameter-of the helix 3'! formed of the wire 20, and an outer flange .38 having a shoulder:39 adapted to .bear against, .and to cover, theinlet end 40 of the ribbon 20. The external diameter of the flange .38 is preferably substantialy equal to the external diameter of the helix..31. The outer face 4| of the flange 38 is preferably smooth. The mandrel 36 preferably comprises anaxial, smooth channel 42xopening at one end on'the outerface 4i, and .-at the other end into theiflexibleinteriorof thehelix .3]. Theouter and inner edges, 43 and respectively, of the channel .42 arepreferably smoothly rounded.

An outlet conduit 45 is preferably disposed at the outlet end of the guide tube HI; and comprises a mandrel 46 of an external diameter-substantially equal to, orslightly greaterthan the internal diameter of the helix 31. The inlet .end or port 41 and the outletend or port 48 Toflthe conduit .45 are preferably smoothly rounded, and

disposed at projecting from the conduit 45, and intermediate the inlet .and outlet ends kl andAB, is a flange 50 havingan external diameter substantially equal to the external diameter of the helix .57. The rearward face 5| of the flange 50 is preferably perpendicular to the axis of the conduit '45, and is preferably joined to the outer face of the rearward portion52 of the mandrel 46 by a circularly concave portion or track 53. The forward portion .54 of the conduit 46 extends from the outlet end 48 rearwardly to the flange 5D to "which it is preferably joined by a chamfered ed e-.55.

In practice, the inlet mandrel 36 preferably extends .interiorly of the helix 31a di-Stanceof two or more .convoluti s, .In simi ar manner. the rear portion 52. .of the outletmandrel 46 prererably extends interiorlyof, the helix3'l a distance ofatleast more than one convolution.

The .jaws l3 and [4 preferably have formed therebetween, a hollow cylindrical channel .Btof configuration substantiallyequal to the external periphery of the flexible guide .tube l0. when said jaws are slightly spread.

In operation, the jaws i3 and 14 of the carrier 12 are spread, as by any suitable instrument .(notshown), and the flexible guide tube I0 is inserted therebetween, with the inlet mandrelpontion .36 adjacent the J'aws l3 and M, and said jawsare .then released until theygrip saidinlet end, bearing against the convolutions 56, 5! surrounding the mandrel 36 and forcing them thereagainst, thereby augmenting the normal spring pressure of-said convolutions against said mandrel .36. In a preferred use of my invention, the flangeimisdisposed outside the path of the jaws i3 and I4, although my invention will work even if saidjaws bear thereagainst.

In the c e i lus ate infieu es .1 nd 2. the external ends 58 and-359 respectively of the jaws l3 and M are curvedaway from the. flexible guide tube lflso as to: allow for deflection of the tube. Moreover, the :tube ill extends beyond-the region of the ends 58 and 59 of .the carriena substantial distancm-nnd theoutlet end 54 of the tube It is of substantially less diameter thanthe thickness of the ca frier jaws 13, i4, Thus, the flexible gu de tube of my inven ion; makes. it-P sible to utilize a plurality of. carriers in the closest lead to the smooth, axial channel 49 extending possible relation :to the sinkers, without interferme. with eachn her.

s s n Figu e th guide a tube is fix d with respect toitself, in those portions thereof where thehelix 3."! embracesthe channeled'mandrels3$ and 4.6, and .is flexible atall portions thereof intermediatesaid channeled mandrels 3t and 46 .Moreoyer, an'pnbroken outer face 38 is presented, whereas the interior of the flexible portion is broken "by the continuous helical chamfer *2! presenting a-series-of stages 6], 62, 63, etc. Thus, in cases of jarring the carrier '12 at-the end of -a course-laying stroke, Whereas a harmonic-period of vibration could have'been establishe'd between:the vibration of the exterior face/3i): and'the interior face 3| if such interior face'were .:continuous-.and unbroken, it .is sub stantially impossible to establish such a period of vibration ,With ,the broken interior face .523. Instead, bymeansof myinvention each convolution .of the interior face 2-3; serves todampen anytendency of the exterior face 30 to vibrate. As aresult, extraneous movement of the outlet tube 45 from jarring or other vibration, is ;in-. hibited; and the yarn is laid .trueto course.

Moreover, when the guide tube I0 is deflected as by contact with an object disposed in its'p'ath, the circularly concave juncture'between the flange 53 and the mandrel 46 permits flexing of the convolutions on' the mandrel without binding. In the course of deflection, various of its convolutions will be separated, as illustrated in Figure 4; nevertheless, the yarn l8 passing through the guide tube iUwill not be caught between the convolutions. This is so because the perpendicular edge 64 at one end ofa convolution 21, holds the yarn within the interior 3| of' the guide tube l; whereas the chamfered edge 2| of the next succeeding convolution 24 recedes from the yarn [Sand provides a non-cooperating surface with respect to the perpendicular edge 22 of the'convolution 21. Thus, as'the convolutions 24 an'd'2l recoil back toward undeflected condition, as'for instance illustrated in Figure 5, the chamfer 2| does not cooperate with the normal edge 22 to pinch the yarn l8-therebetween. Instead, the chamfered edge 2| cams the yarn 18 away from its edge 26 and into the interior 3! 0f the guide tube [0. Thus, in practice, as the deflected guide tube recoils back to normal undefiected position, the yarn I8 is guided free of pinching contact between the separated convolutions 24 and 21, thereby enabling it to continue to be paid out in normal course-laying operation through the guide tube Ill.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiments to be consideredin all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having thus described my invention, what I claim as new and desire to obtain byLetters Patent is:

1. A flexible guide tube comprising a substantiallyflat ribbon having substantially parallel longitudinal edges, a guide face and an outer face, said ribbon being formed into a helix having a plurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal edges; the longitudinal contour of said inner channel consisting of a series comprising a guide face portion extending substantially to one longitudinal edge portion, a chamfered edge on the next succeeding convolution, substantially adjacent said last-mentioned longitudinal edge portion but spaced from said guide face portion, and

the next succeeding guide face portion substan-,

tially extending from said chamfered edge portion substantially to the next succeeding longitudinal edge portion of said last-mentioned convolution; an inlet conduit disposed at an inlet portion of said helix; and an outlet conduit disposed at an outlet portion of said helix; said inlet conduit comprising a shoulder adapted to cover at least a portion of the inlet terminus of said ribbon ;and said outlet conduit comprising a shoulder adapted to cover at least a portion of the outlet terminus of said ribbon, andalso comprising a channel extending from the interior of said helix to an outlet port substantially beyond the outlet terminus of said helix; the external diameter of said outlet conduit adjacent said outlet port being less than the external diameter of said helix; and said inlet and outlet tubes being in a spaced relation to each other.

2. A flexible guide tube comprising a substantially fiat ribbon having substantially parallel,

longitudinal edges, a guide face and an outer face,

said ribbon being formed into a helix having aplurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal tudinal edge portion of said last-mentioned convolution; and an outlet conduit disposed at an outlet portion of said helix; said outlet conduit comprising a shoulder adapted to cover atleast a portion of the outlet terminus of said ribbon, and also comprising a channel extending from the interior of said-helix toan outlet port sub helix; the external diameter of'said outlet conduit adjacent said outlet port being less than the external diameter of Said helix.

3. A flexible guide tube comprising a substantially flat ribbon having substantially parallel longitudinal edges, a guide face and an outer face, said ribbon being formed into a helix having a plurality of convolutions withsaid guide face defining an inner channel; a chamfered edge between said guide face and one-of said longitudinal edges; the longitudinal contour of said inner channel consisting of a series comprising a guide face portion extending substantially to one longitudinal edge portion, a chamfered edge on the next succeeding convolution, substantially adja'-' centv said last-mentioned longitudinal edge portion but spaced from said guide face portion, and the next succeeding guide face portion substantially extending from said chamfered edge interior of said helix to an outlet port'substantially beyond the outlet terminus of said helix.

. 4. A flexible guide tube comprising a substan-' tially flat ribbon having substantially parallel longitudinal edges, a guide face and an outer face, said ribbon being formed into a helix having a plurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal edges; the longitudinal contour of said inner channel consisting of a series comprising a guide face portion extending substantially to one longitudinal edge portion, a chamfered edgeron the next succeeding convolution, substantially adjacent said last-mentioned longitudinal edge portion but spaced from said guide face portion, and the next succeeding guidevface portion substantially extending from. said chamfered edge por-;

interior of said helix to an outlet port substantially beyond the outlet terminus of said helix; and said inlet and outlet tubes being in a spaced relation to each other. 1 r

' 5.. A flexible uide ube cqmnrisire. or substen ia l flat ribbon hav n ub nt a lr paral el. on itud na ed esesu d seandano ter. taco. said ribb n. bein termed: into. a. he ix. ha n a. pluralitr of; convq utions; wi h; aid. uide a e. defining. an nner. channel-5; a. ebamf re ed e between sa d guid fac a one or; aid lousir tudina e es; he lon i udinal. on our o said. nner o aune o sistine o ase ies: comp isin uide. f are. portion. extendin sub antia-lly' t ne n udinal, ed e. portion. a. ham erededse on; the. next su c din onvo ution. substau iallli' adiace .aid lastrmentioned onsitudinak ed e; porti n-bu snaced. fr m. sa d. sn e. ace; po ion. ndtbe nexts ce edine u d a t on ub.- tant ally exten in from. aideoam ed e n rti nsubstantially to the. x s eed aloneitudinal. ed e portion. of said; last-men ioned: con ut o ani et condu disnos d ateninlet port: nosed span utl portion of said; he ix; 5 115110111 l t onduit omp isi che n lv xt ndine.Horn the interior of said. helix to anoutlet port. substantiallr eyond he utlet term n s of said.

helix; th ext r l iameter qisaid ntleb ooduit.

adja t s e port. b i l ss: than. the. external. di meter. of. aid. lix; and: aid. nl andouflettub s.b ine n a pac d sla-tion t ach Qt Qrj 6.. A flexibl uide $1 .12 c mpris n a substanially flat ribbo havine substant a ly. parall longitudinaledges,,aguide faceandan outer; face, said: rib on b ing. ormed nt a. h ix: hav n a n uraliw; of. conyolutions; with... aid guide. face defin ng an. inner: h nn l; a. h mfe ed. ed e. betweensaid guide, face and one of said; longitudinal; edges,- the longitudinal contour olsaid, inn r. hannel con isting. of a s ies. omprising a uide. faqep rt o extend n substantially to. one longitudinal, edge portion, a chamfered; edge on the next succeeding convolution, substantially a jacent sai lastrm ion d. l ngitudinal edge portion but spaced from said guide, face portion, and the next succeeding guide face portion substantially extending from. said chamiered edge portion; substantially to the next; succeeding. 1011-! gitudinal' edge, portion ofv said last-mentioned convolution; an inlet conduit disposed at. an inlet. portionof; said helix; said inlet conduit comprise ing-ashoulder. adapted to cover at least aportion of the. inlet. terminus. of said ribbon.

7 A flexible guide tube; comprising; asubstam. tially flatv ribbon= having substantially parallel: longitudinal edges, a guide. face. and an outer.- f-ace, said ribbonbeing formed into a helixhavinga. plurality of convolutions with said guide: face defining. an, inner. channel; a chamieredi edge between said guide iace. and: one or said longiatudinal edges; the. longitudinal contour of said inner channel. consisting of a-.series comprising a guide face; portion extending substantiallyto one longitudinal edge portion, a. chamfered edge on the next succeeding convolution, substantially; adjacent said last-mentionedv longitudinal:- edge portion but. spaced" from said guide. face portion, and; the. next succeeding guide faceportion sub stantiallyextending; from said chamfered edge portion substantially: to. the next; suoceedinglona. gitudin'al edge portion of said lastamenti'oned convolution.

- 8; A flexible guide tube comprising: a. substan-. tially flat. ribbon having substantially-parallel longitudinal edges, a guide i-aceandz an outer iacei said; ribbon being formed; into a. helix having a plurality of convolutions with saict guide-face on. of. s d el x; and an o let conduit l a w thin s id helix. nd radially supporting at least a portiorr thereoi; and. a, channel disposed through said mandrel; and in, communication with at. least, a, portion of, said firstrmentioncd; channeL.

9;. A iiexible guide tube. comprising, a. substan 'tially flat ribboni having substantially. parallel all;

longitudinal, edges,, a, guide face and; an. outer; face, said ribbon being formed into a helix having, a. plurality: of convolutions. with said guide faces defining.- an, inner channel; a chamfered edge be.

tween said guide-race and oneof said longitudinal; edges; the longitudinal contour of said inner; channel; consisting of a. series comnrising a. guide face portion extending substantially to one lon i i,

. tudinal edge portion, a. chainierededge, on. the

next succeeding convolution, substantially ad. jacent said, last-mentioned longitudinal} edge. portion but spaced from said guideface portion and thenext succeeding guide face porticn.sub-'-' stantially extending from said. charnf'eredi edge portion substantially to. the next succeeding longitudinal edge portion of said last-mentioned convolution; a mandrel disposedwith-in said helix andradially supporting at least a portion thereof; and a channel disposed through said mandrel and in communication with at least a portion of said" first-mentioned channel; a shoulder projecting from saidmandrel' and covering at least a part of a terminus of said ribbon. 1

10; A- fiexible guide tube comprising a substan tially flat ribbon having substantially parallellongitudinal edges, a guide face: and an outerface, said ribbon being formed intoa helix having a plurality of convolutionswith said guide facedefining an innerohannel: a chamfered edge be.

tween said guide faceand one of: said longitudinal edges; the longitudinal contour: of. said inner channel: consisting: of a series comprisinga guide face portion extending substantially-"to one longitudinal edge portion,'a chamf'eredi edge: on:

" the: next succeeding convolution, substantially:

adjacent said last-mentioned longitudinal: edge portion but spaced from said guide-face portion, and the next succeeding-guide face portion sub stantially. extending from: said chamfered edgeportionsubst-antialiy to the next succeeding: lcngi tudinal edge portion of: said last-mentioned convolution; a mandreldisposed within saidhelixand: radially. supporting atleast a portion: thereof; and a? channel disposed through said mandrel and in communication with at least-a portion of said first-mentioned channel;*ashoulder pro-- jecting from said mandreland covering at leasta part of a terminus of said ribbon-;- and anout let conduit disposed at an outlet por-t ionofsaid helix; saidi'outlet conduit comprising a shoulder adapted to cover at least a portion of the outlet terminusofsaid ribbon, and also comprising a channel extending from the interiorof said helix toan outlet port substantially beyond the outlet terminus ofsaid-helix-z 11. A flexible guide tube comprising a substantially flat ribbon having substantially parallel longitudinal edges, a guide face and an outer face, said ribbon being formed into a helix having a plurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal edges; the longitudinal contour of said inner channel consisting of a series comprising a guide face portion extending substantially to one longitudinal edge portion, a chamfered edge on the next succeeding convolution, substantially adjacent said last-mentioned longitudinal edge portion but spaced from said guide face portion, and the next succeeding guide face portion substantially extending from said chamfered edge portion substantially to the next succeeding longitudina1 edge portion of said last-mentioned convolution; a mandrel disposed within said helix and radially supporting at least a portion thereof; and a channel disposed through said mandrel and in communication with at least a portion of said first-mentioned channel; a shoulder projecting from said mandrel and covering at least a part of a terminus of said ribbon; and an outlet conduit disposed at an outlet portion of said helix; said outlet conduit comprising a shoulder adapted to cover at least a portion of the outlet terminus of said ribbon, and also comprising a channel extending from the interior of said helix to an outlet port substantially beyond the outlet terminus of said helix; the external diameter of said outlet conduit adjacent said outlet port being less than the external diameter of said helix; and said inlet and outlet tubes being in a spaced relation to each other.

12. A flexible guide tube comprising a substantially flat ribbon having substantially parallel v longitudinal edges, a guide face and an outer face,

said ribbon being formed into a helix having a plurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal edges; the longitudinal contour of said inner channel consisting of a series comprising a guide face portion extending substantially to one longitudinal edge portion, a chamfered edge on the next succeeding convolution, substantially adjacent said last-mentioned longitudinal edge portion but spaced from said guide face portion, and the next succeeding guide face portion substantially extending from said chamfered edge portion substantially to the next succeeding longitudinal edge portion of said last-mentioned convolution; and an outlet conduit disposed at an outlet portion of said helix; said outlet conduit comprising a flange substantially radially projecting from said conduit intermediate the ends thereof.

13. A flexible guide tube comprising a substantially flat ribbon having substantially parallel longitudinal edges, a guide face and an outer face, said ribbon being formed into a helix having a plurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal edges; the longitudinal contour of said inner channel consisting of a series comprising a. guide face portion extending substantially to one longitudinal edge portion, a chamfered edge on the next succeeding convolution, substantially adjacent said last-mentioned longitudinal edge portion but spaced from said guide face portion,

and the next succeeding guide face portion substantially extending from said chamfered edge portion substantially to the next succeeding longitudinal edge portion of said last-mentioned convolution; and an outlet conduit disposed at an outlet portion of said helix; said outlet conduit comprising a flange substantially radially projecting from said conduit intermediate the ends thereof; a mandrel portion disposed between said flange and one of said ends of said conduit; and a track disposed between said flange and said mandrel and adapted to permit flexing movement thereon of an end convolution of said helix.

14. A flexible guide tube comprising a substantially flat ribbon having substantially parallel longitudinal edges, a guide face and an outer face, said ribbon being formed into a helix having a plurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal edges; the longitudinal contour of said inner channel consisting of a series comprising a'guide face portion extending substantially to one 1on gitudinal edge portion, a chamfered edge on the next succeeding convolution, substantially adjacent said last-mentioned longitudinal edge portion but spaced from said guide face portion, and

the next succeeding guide face portion substantially extending from said chamfered edge portion substantially to the next succeeding longitudinal edge portion of said last-mentioned convolution; and an outlet conduit disposed at an outlet portion of said helix; said outlet conduit comprising a flange substantially radially projecting from said conduit intermediate the ends thereof; a mandrel portion disposed between said flange and one of said ends of said conduit.

15. A flexible guide tube comprising a substantially flat ribbon having substantially parallel longitudinal edges, a guide face and an outer face, said ribbon being formed into a helix having a plurality of convolutions with said guide face defining an inner channel; a chamfered edge between said guide face and one of said longitudinal edges; said inner channel comprising an inlet portion and an outlet portion; the longitudinal contour of said inner channel from proximity to said inlet portion toward said outlet portion, consisting of a series comprising a guide face portion extending substantially to one longitudinal edge portion, a chamfered edge on the next succeeding convolution, substantially adjacent said last-mentioned longitudinal edge portion but spaced from said guide face portion, and

the next succeeding guide face portion substan-' tially extending from said chamfered edge portion substantially to the next succeeding longitudinal edge portion of said last-mentioned convolution.

LEON BARRETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,048,471 Sanford July 21, 1936 2,086,321 Kuds July 6, 1937 2,101,801 Weisbecker Dec. 7, 193'! 2,453,513 Jauch Nov. 9, 1948

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