CA1310800C - Reinforced strip and flexible hoses produced therewith - Google Patents

Abstract

Strips for use in forming flexible hoses from helically wound convolutions of the strip are disclosed, in which the strip has a substantially U-shaped body including a pair of radially projecting, spaced-apart walls connected by a transverse wall, and in which the body is produced from a polymeric material having a predetermined Young's modulus, and substantially the entire surface of the body is composed of that polymeric material, so that adjacent portions of the body can be directly bonded together to form a flexible hose upon the helical winding of the strip. Furthermore, supports are embedded in the pair of walls in order to reinforce the walls and permit the body to substantially retain its shape upon the application of external forces thereto. Methods for making flexible hoses from these strips are also disclosed.

Description

~EINFORCED STRIP AND FLExIBLE HOSES PRODUCED THEREWITH
The pr~sent invention is directed to strips for use in forming flexible hoses. More particularly, the present invention rel~tes to flexible hoses produced from such strips, and to methods for producing flexible hoses from helically wound strips.
It has been known for many years that ~lexible plastic hoses can be produced by winding one or more strips or elongated members formed from polymeric materials into a helical structure. Upon winding displaced portions of these strips on adjacent turns of the helix, these adjacent turns, which have been referred to as connecting portions, can then be secured together, such as by the use of polymeric bonding material or hot m~lt compositions. These molten bonding materials are ordinarily applied to a connecting portion of such a member as it is wound into the helical structure.
Such helically wound flexible hoses, as disclosed for example in Richitelli, U.S. Patent NoO
3,199,541, have included both the use sf a single strip-like member with a U-shaped channel on one edge and a projection on the opposite edge, and a two-strip hose produced ~rom a U-shaped channel member and a cap member wound in alternating turns. The Richitelli patent also includes the use of a reinforcing material 38, such as that shown in FIGS. 6-11 thereof, which is said to be substantially stiffer than the other hose materials, and which is arranged on the radially extending walls of the hose. This patent contends that the purposa o~ same is u to provide a stiff reinforcing element between the convolutions of the hose. In some embodiments thereof, ths reinforcing material, comprising polyethy].ene or polyethylene copolymers i5 extruded and united with the basic strip immediately after the extrusion process, and the reinforcing material is exposed to the surface of the strip so that the bond between adjoining strips may involve bonding of the reinforcing material of one strip to the softer material of an adjoining strip.
lG Another such strip material.is shown in Finley, U.S.
Patent No. 4,383,555, in ~hich the strips include a thin web or membrane 21 of relatively soft material and a pair of relatively rigid rib components extending alon~ the opposite maryins of that web and co-extruded therewi~-h.
In addition, the applicant has discovered that such spirally wound hoses can be produced with enhanced structural strength and integrity., and still remain readily bondable by fusing a buffer material which is more readily susceptible to fusion under heat and/or pressure to a structural material which is a relatively difficult to fuse polymeric material having greater strength and rigidity. Molten polymeric bonding material can then be used to bond these buffer materials together.
In accordance with the present invention, the deficiencies of the prior art helically wound flexible hoses have now been overcome by the discovery of a strip material .~

1 3 1 080~

for use in forming a flexible hose from helically wound convolutions of that strip.
According to the present invention then, there is provided a strip for use in forming a flexible hose from helically wound convolutions of the strip, the strip comprising a substantially U~shaped body portion including a pair of radially projecting, spaced-apart wall members connected by a transverse portion, the body portion comprising a first polymeric material having a predetermined Young's modulus, substantially the entire surface of the body portion comprising the polymeric material, whereby adjacent portions of the body portion can be directly bonded together to form the flexible hose upon the helical winding of the strip, the spaced-apart wall members comprising first and second plate-like support members embedded within th~ wall members, the first and second plate-like support members comprising a second polymeric material having a predetermined Youngls modulus higher than the predetermined Young's modulus of the first polymeric material of the body portion, whereby the transverse portion is substantially free of the plate-like support members, the plate-like support members thereby reinforcing the wall members and permitting the body portion to substantially retain its shape upon the application of external force thereto.
~ he hose of the present invention comprlses a helically wound strip defining a plurality of turns, the strip comprising a substantially U-shaped body portion including a ~b ~ 3 1 ~8''1~

pair of radially projected spaced-apart wall members connected by a transverse portion, the body portion comprising a first polymeric material having a predetermined Young~s modulus, substantially the entire surface of the body portion comprising the polymeric material, whereby adjacent portions of the plurality of turns of the strip can be directly bonded together to form the hose, the pair of wall members comprising first and second plate-like support members imbedded within the pair of wall members, the first and second plate-like support members being spaced apart by the transverse portion and comprising a second polymeric material having a predetermined Young's modulus higher than the predetermined Young's modu~us of the first polymeric material of the body portion, whereby the transverse portion is substantially free of plate-like support members, the plate-like support members thereby reinforcing the wall members and permitting the body portion to substantially retain its shape upon the application of external force thereto.
A method for making a flexible hose is also provided~ comprising providing a stri.p comprising a substantially U-shaped body portion including a pair of radially projecting ~paced-apart wall members connect.ed by a transverse portion, the body portion comprising a first polymeric material having a predetermined Young's modulus, substantially the entire surface of the body portion comprising the polymeric material, and radially projecting first and second plate-like support members imbedded in the ;~

pair of wall membersl the first and second plate-like support members comprising a second polymeric material hav.ing a predetermined Youngls modulus higher than th~ predetermined Young's modulus of the first polymeric material of the body portion, whereby the transverse portion is substantially free of plate-like support members, the plate-like support members thereby reinforcing the wall members and permitting the body por~ion to substantially retain its shape upon the application of external force thereto, winding the strip into a generally helical configuration so that the strip forms a plurality of turns, whereby displaced sections of the radially projecting wall members are juxtaposed with one another, and directly bonding the }uxtaposed sections of the wall members together to form the flexi~)le hose.
In accordance with preferred embodiments of the present invention, the method includes co-extruding the body portion and the first and second plate-like support members to produce the strip, and the plate like support members are embedded within the body portion, and follow the shape of the body portion for a predetermined portion thereof. In another preferred embodiment, the plate-like support members are radially projecting and are embedded in the wall members.
The present invention can be more fully appreciated ~: with reference to the following detailed description, which refers to the attached drawings in which:
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, . , ' ~ 3 1 ~ 8 0 ~
5a-FIG. 1 is a schematic, sectional view showing portions of a hose according to one embodiment of the present invention;
FIG. 2 is a fragmentary view tiaken on an enlaryed scale of a portion of the hose shown in FIG. l;
FIG. 3 is a si.de, sectional view of a portion of a hose produced in accordance with another embodiment of the present invention;
FIG. 4 is a side, sectional view of a portion of a hose produced in accordance with another embodiment of the present invention;
FIG. 5 is a side, sectional view of a portion of a hose produced in accordance with another embodiment of the present invention; and FIG. 6 is a side, sectional view of a portion of a hose produced in accordance with another embodiment of the present invention.

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-6- ~ 31 o~an Referring next to the figures, in which like numerals refer to like portions thereofl channel member 10 employed in preparing a flexible hose in accordance with the present invention is generally U-shaped in section. Unless otherwise indicated, the descriptions in this disclosure of the shape of an elongated member or strip 'Jsection~ should be unders~ood as referring to thP shape of the me~ber viewed in a cross-section taken on a cut~ing plane transverse to its direction of elongation. Ordinarily~ although not necessarily, the elongated members are substantially uniform in cross-sectional shape throughout their length.
Channel member 10 includes a transverse wall portion 12 and a pair of radially projecting~
substantially parallel side wall portions 14 and 16.
Transverse wall portion 12 includes an inner surface 1~, whil~ radially projecting side walls 14 and 16 include inner sur~aces 20 and 22, respectively, which face towards each other, thus creating inner space 24 therebetween. One side wall 14 terminates in transversely extending end portion 26, which extends only a short distance from the side wall 14. The other sids : wall 16 terminates in longer transversely ex~ending side portion 28, which includes a radially extending end portion 30, thus forming a channel portion 31 (as can best be seen on the left-hand side of FIG. 2) between the radially extending side wall portion 16 and the radially extending end portion 30. As will be explained in more detail below, production of a flexible hosa from this _7_ 1 3 ~ ù~

channel member or strip results from helical winding of the strip so that the transversely extending end portion 26 at the end of wall portion 14 enters into the channel portion 31 ~ormed between radially extending wall portion 16 and radially extending end portion 30. Furthermore, production of such a 1exible hose also includes the presence of bonding material 32 within channel portion 31, which assists in effecting a w~ld between the side walls forming the channel portion 31 and the end portion 26 of the wall portion 14. The bonding material 32 can best be seen on the righhand side of in FIG. 2 hereof.
Channel or strip member 10 itself is formed substantially entirely of a readily fusible, low melting material, such as ethylene ethyl acrylate (EE~), ethylene vinyl acetate (EVA), and other such polymers having a low Young's modulus, which are thus readily fusible in accordance with the preparation of a hose in accordance herewith.
l'hese includ various other ethylene copolymers, preferably with acrylic acid esters, or vinyl esters, so that these copolymers have the overall physical properties discussed above.
~ his material from which the channel or strip member 10 is formed thus constitutes the entir~ outer surface o~ strip 10. Thus, by merely interposing bonding material 32 therebetween, direct welding of these adjacent portions of the strip 10 can be effected, as shown in the figure~, so as to produce th~ flexible hoses of this invention. However, because o~ the nature of these materials used to ~or~ the strip 10, they do not ! Jl ~8C 3 have the structural s~ability to resist subsequent collapse, such as upon the exertion o~ external forces created by vacuum and other pres~ures within the hose which can be anticipated during use. Therefore, within the strip itself, for example within and parallel to radially projecting side walls 14 and 16, there are included plate-like strips of rein~orcing material 34 and 36, respectively. These plate-like strips of reinforcing material are formed from a relatively high melting, but difficult to fuse structural material, such as linear low density polyethylene (LLDPE), high density polyethylene (HDPE~, a group of monomer resins sold under the trademark SURLYN by E.I. DuPont de Nemours & Co., and other such high Young~s modulus polymeric materials.
The reinforcing plate-like strips 34 and 36 can be formed wi.thin the radially projectiny ~ide wall members 14 and 16, respectively, in a coextrusion process. As the process of coextrusion per se is conventional and well Xnown to those skilled in the plastic arts, this procPss need not be described in detail herein. The coextrusion pxocess typically brings each material to a liquid state and unites the flowing liquid streams. In coextrusion, the heat and pressure which may be applied to cause fusion o~ the two materials are limited only by ~he degradation temperature of the materials and the capacity o the equipment. ~ecause conditions of heat and pressure far more severe than those attainablé during the hose winding operation can be applied during the coextrusion operation, the two , ~ ~, . . .

9 1 3 1 ~u~

materials in question can be readily united during coextrusion.
The thickness of the mat~rial forming the strip 10, including transverse wall me~ber 12 and radially projecting wall portions 14 and 16, is generally between about .020 and .060 inche~, and more praferably between about .035 and .045 inch~s. The thi.cknsss of the ~upport members 34 and 36, however, is g~nerally between about .005 and .05C inches, and most preferably between about .015 and ~030 inches.
As discussed above, and as can be shown more clearly in FIG. 1, the channel or strip member 10 thus described is wound on a generally cylindrical mandrel 50 having an axis 52 so that the strip member is formed into a plurality of turns and hence into a helix extending along axis 52. The side wall~ o neighboring turns of strip member 10 are juxtaposed with one another, so that the radially projecting side wall 14 of one ~urn of the strip me~ber is juxtaposed with the radially projecting side ~all 16 of the neighboring turn. More particularly, these side walls are juxtaposed in a manner such that the end portio~ 26 of radially projecting side wall member 14 enters into th~ channel 31 created between the radially projecting wall member 16 ~nd radially extending end portion 30 of the adjacent turn. Prior to winding of each such turn, however, ~olten bonding material 32 is deposited in channel 31. Thusj when molten bonding material 32 is applied concomitantly with this winding process, and is introduced into channel 31 æhortly before -10~ o a the next adjacent portion of the radially projecting side wall member 14 enters the channel 31 in the helical winding process, the bonding material 32 substantially ~ills channel 31, and the transversely extending end portion 26 of radially projecting side wall portion 14 enters into that channel, and hence into the bonding material 32 under the pr ssure exerted by the helical winding process itsel~. The bonding material 32 then progressively cools and solidifies, and bonds these edge regions of these wall portions to one anothax. The bonding material 32 itself consists primarily of materials such as ethylene vinyl acetate (EVA) or ethylene ethyl acrylate (EEA), which cannot only effect the bonding discussed herein, but which are thus also fully compatihle with the outer surfaces of the ~trip 10, as discussed hereinbefore. The bonding material 32 is itself desirably maintained at a temperature of between about 350 and 500F when introduced into the channel 31.
The relevant portions o~ the strip 10 should be at least at about room temperature when they contact the bonding material 32. Also, the bonding material should be introduced.into channel 31 no more than about two seconds before that portion of the channel is engaged with the transversely extending end portion 26 of the next winding ; of the radially projecting side wall portion 14.
Extraordinary bond strength is developed between the bonding materi~l and the juxtaposed portion~ of the strip in this manner. Thus, the finished hose is rugged and 1 3 ~ 0~3C)O

permits full exploitation of the strength created by the overall s~ructure in accordance with this invention.
As will be readily appreciated, numerous variations and combinations of the features described above can be utilized. Thus, the siæe and relative proportions of the members can be varied. Furthermore, provision of the strllctural ~upport for t~.e strip 10 can be made in other ways. For example, as shown in FIG. 3, plate like rein~orcing material can be provided in the transverse wall portion 12 by means o~ transversely extending plate-like portion 36, and in addition smaller plate-like portions 38 and 40 can be provided at the arcuate end portions of the radially projecting side wall portions 14 and 16, respectively, i.e., where the inner ends of these side wall portions meet and extend into transversly extending end portions 26 and 28, respectively. In yet another embodiment shown in FI&. 4 hereof, the trip 10 again includes a transverse wall portion 12, radially projecting side wall portions 14 and 16, as above, but in this case inwardly projecting side wall portion 16 terminates at 42, while radially projecting- side wall portion 14 extends into transverse inner wall portion 44, which itsel~ te~minates in a short radially projecting portion 46. Thus, upon helical winding of this embodiment of strip 10, this short radially projecting portion 46 enter~ into the channel created within the U~shaped member created by radially projecting side wall portions 14 and 16, and transverse -12- 1 3 1 0~03 wall portion 12, which channel can th~n include the bonding material 32 therein.
Referring next to FIG. 5, yet another embodiment of strip lOa used to form the flexible hose of the present invention is shown therein. In this embodiment the strip member lOa includes a transverse wall portion 12a, and radially projectin~ side wall porticns 14a and 16a. These side wall portions 14a and 16a include edge portions 54 and 56, respectively, remote from transverse wall portion 12a. ~he plate-liXe reinforcing strips 34a and 36a in this case are embedded in side wall portions 14a and 16a, respectively.
In the embodiment of FIG. 5, a U-shaped cap member 58 is also employed, and acts as a second strip for producing the flexible hoses h reof. Cap member 58 : has a crown wall 60 and lateral walls 62 and 64 ;~ projecting generally co-directionally Erom the crown wall 60. The in~erior surfaces of the cap member 58 thus form a trough 66. In this case the U-shaped cap member 58 is again formed from the same lower melting buffer materials, such as the EEA and EVA materials discussed above.
After winding the strip member lOa of FIG. 5 on generally cylindrical mandrel 50 in the manner shown in FI~. 1 so that the side walls of neighboring turns of strip member lOa axe ~uxtaposed with one another such that the first side wall 14a of one turn of this strip member i9 juxtaposed with the second side wall 16a of the neighboring turn, each such pair oP juxtaposed strip '' ' -13~ U ~

member side walls defines a projecting ridge extending along the helix defined thereby. Cap member 5~ is then wound onto the partially fo~med helix defined by the strip member, i.e., so that the ridge defined by neighboring turns o~ the strip me~er enter into the trough 66 of cap member 58. As in the case in the other embodiments of this invention, each portion of the cap member 58 moves downstream on the helix and passes the depositing station in which molten bonding material 32a 19 is deposited in trough 66. In this manner, the molten bonding material 32a is applied concomitantly with the winding process, and is introduced into each portion of the cap member 58 shortly before that portion of the cap member receives the side walls of the strip member lOa in the helical winding process.
Referring next to FIG. 6, another embodiment of the strip member lOb of the present invention is shown therein. In this embodiment, the strip lOb has the same general con~iguration as the strip lO shown in FIGS. l and 2 hereof. However, in this case instead of the reinforcing plate-like membars 34 and 36, reinforcement is provided by inwardly pro~ecting members 68 snd 70 which extend within the inner surface of these U-shaped members from ~he inner sur~aces of radially projecting side wall portions 14b and 16b, respectively. Therefore, upon the exertion of external force to the hose produced ~rom this strip member lOb, the projecting me~bers 68 and 70 will be forced together, and only a small amount of di~tortion is pe~nitted, i.e., until these projecting -14- l-7:l 0 ~ ~ 3 mam~ers cross the gap 72 initially therebetween (i.e., when it is in its relaxed state). Thereafter, their contact substantially prevents further such distortion.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these e~bodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative 1o embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (24)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A strip for use in forming a flexible hose from helically wound convolutions of said strip, said strip comprising R substantially U-shaped body portion including a pair of radially projecting, spaced-apart wall members connected by a transverse portion, said body portion comprising a first polymeric material having a predetermined Young's modulus, substantially the entire surface of said body portion comprising said polymeric material, whereby adjacent portions of said body portion can be directly bonded together to form said flexible hose upon said helical winding of said strip, said spaced-apart wall members comprising first and second plate-like support members embedded within said wall members, said first and second plate-like support members comprising a second polymeric material having a predetermined Young's modulus higher than said predetermined Young's modulus of said first polymeric material of said body portion, whereby said transverse portion is substantially free of said plate-like support members, said plate-like support members thereby reinforcing said wall members and permitting said body portion to substantially retain its shape upon the application of external force thereto.

2. The strip of claim 1 wherein said plate-like support members follow the shape of said body portion for a predetermined portion thereof.

3. The strip of claim 2 wherein said plate-like support members are radially projecting.

4. The strip of claim 1 wherein said first polymeric material comprises a polymer selected from the group consisting of ethylene ethyl acrylate and ethylene vinyl acetate.

5. The strip of claim 1 wherein said second polymeric material comprises a polymer selected from the group consisting of linear low density polyethylene, high density polyethylene and SURLYN.

6. The strip of claim 1 wherein said body portion includes a connecting portion extending lengthwise along said strip, whereby displaced sections of said connecting portion are juxtaposed with one another upon said helical winding of said strip.

7. The strip of claim 6 wherein said connecting portion extends transversely from at least one of said wall members at a location distal from said transverse portion thereof.

8. The strip of claim 1 including a generally U-shaped cap member including a crown wall and a pair of lateral walls extending from said crown wall substantially parallel to each other, so as to define a slot therebetween, whereby displaced sections of each of said wall members are juxtaposed with one another upon said helical winding of said strip and may be contained within said slot.

9. The strip of claim 1 wherein said body portion and said plate like support members comprises co-extruded portions of said strip.

10. A hose comprising a helically wound strip defining a plurality of turns, said strip comprising a substantially U-shaped body portion including a pair of radially projected spaced-apart wall members connected by a transverse portion, said body portion comprising a first polymeric material having a predetermined Young's modulus, substantially the entire surface of said body portion comprising said polymeric material, whereby adjacent portions of said plurality of turns of said strip can be directly bonded together to form said hose, said pair of wall members comprising first and second plate-like support members imbedded within said pair of wall members, said first and second plate-like support members being spaced apart by said transverse portion and comprising a second polymeric material having a predetermined Young's modulus higher than said predetermined Young's modulus of said first polymeric material of said body portion, whereby said transverse portion is substantially free of plate-like support members, said plate-like support members thereby reinforcing said wall members and permitting said body portion to substantially retain its shape upon the application of external force thereto.

11. The hose of claim 10 wherein said plate-like support members follow the shape of said body portion for a predetermined portion thereof.

12. The hose of claim 11 wherein said plate-like support members are radially projecting.

13. The hose of claim 10 wherein said body portion includes a connecting portion extending lengthwise along said strip, whereby displaced sections of said connecting portion are juxtaposed with one another in adjacent turns of said hose.

14. The hose of claim 13 wherein said connecting portion extends transversely from at least one of said wall members at a location distal from said transverse portion thereof.

15. The hose of claim 10 including a generally U-shaped cap member including a crown wall and a pair of lateral walls extending from said crown wall substantially parallel to each other, so as to define a slot therebetween, whereby displaced sections of each of said wall members are contained within said slot.

16. A method of making a flexible hose comprising providing a strip comprising a substantially U-shaped body portion including a pair of radially projecting spaced-apart wall members connected by a transverse portion, said body portion comprising a first polymeric material having a predetermined Young's modulus, substantially the entire surface of said body portion comprising said polymeric material, and radially projecting first and second plate-like support members imbedded in said pair of wall members, said first and second plate-like support members comprising a second polymeric material having a predetermined Young's modulus higher than said predetermined Young's modulus of said first polymeric material of said body portion, whereby said transverse portion is substantially free of plate-like support members, said plate-like support members thereby reinforcing said wall members and permitting said body portion to substantially retain its shape upon the application of external force thereto, winding said strip into a generally helical configuration so that said strip forms a plurality of turns, whereby displaced sections of said radially projecting wall members are juxtaposed with one another, and directly bonding said juxtaposed sections of said wall members together to form said flexible hose.

17. The method of claim 16 including co-extruding said body portion and said first and second plate-like support members to produce said strip.

18. The method of claim 16 wherein said body portion includes a connecting portion extending lengthwise along said strip, and wherein said winding of said strip includes juxtaposing displaced sections of said connecting portions with one another to form said flexible hose.

19. The method of claim 18 wherein said connecting portion extends transversely from at least one of said wall members at a location distal from said transverse portion thereof.

20. The method of claim 16 including providing a generally U-shaped cap member including a crown wall and a pair of lateral walls extending from said crown wall substantially parallel to each other, so as to define a slot therebetween, and winding said cap member simultaneously with said winding of said strip with displaced sections of each of said wall members being contained within said slot.

21. A strip for use in forming a flexible hose from helically wound convolutions of said strip, said strip comprising a substantially U-shaped body portion including a pair of radially projecting, spaced-apart wall members connected by a transverse portion, said spaced apart wall members including an inner surface, said body portion comprising a polymeric material having a predetermined Young's modulus, substantially the entire surface of said body portion comprising said polymeric material, whereby adjacent portions of said body portion can be directly bonded together to form said flexible hose upon said helical winding of said strip, and a pair of projecting members extending from juxtaposed portions of said pair of wall members, said pair of projecting members extending from said inner surface of said wall members and defining a gap within said U-shaped body portion whereby upon the application of external force upon said body portion said gap is closed and further distortion of said body portion is prevented thereby.

22. The strip of claim 21 wherein said projecting members are produced by molding said body portion into a uniting configuration including said projection means.

23. The strip of claim 22 wherein said body portion includes a connecting portion extending lengthwise along said strip, whereby displaced sections of said connecting portion are juxtaposed with one another upon said helical winding of said strip.

24. The strip of claims 21, 22 or 23 wherein said connecting portion extends transversely from at least one of said wall members at a location distal from said transverse portion thereof.