CA1229313A - Flexible corrugated rubber tubing with internal reinforcement - Google Patents
Flexible corrugated rubber tubing with internal reinforcementInfo
- Publication number
- CA1229313A CA1229313A CA000482823A CA482823A CA1229313A CA 1229313 A CA1229313 A CA 1229313A CA 000482823 A CA000482823 A CA 000482823A CA 482823 A CA482823 A CA 482823A CA 1229313 A CA1229313 A CA 1229313A
- Authority
- CA
- Canada
- Prior art keywords
- helical
- sleeve
- helix
- flexible
- corrugated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Shaping Of Tube Ends By Bending Or Straightening (AREA)
Abstract
FLEXIBLE CORRUGATED RUBBER TUBING
WITH INTERNAL REINFORCEMENT
ABSTRACT OF THE DISCLOSURE
A method for making flexible, corrugated rubber tubing with internal reinforcement. An extruded sleeve of uncured rubber is slid axially onto an elongated internal forming member, after which an external forming means is placed around the assembled sleeve and used to form corrugations. The resulting product is heat-treated to set the corrugations and thus to form a flexible cor-rugated tube length. A helix formed of flexible, resili-ent wire rod is pulled through the corrugated tubing in an axial direction and simultaneously rotated in a direc-tion to thread the helical rod into the internal hellcal groove in the sorrugated product. At the same time, the helix is axially extended to reduce its helix diameter.
When the helix has been completely extended through the corrugated tubing, it is released so that it expands radially into tight conformance with the internal helical groove.
WITH INTERNAL REINFORCEMENT
ABSTRACT OF THE DISCLOSURE
A method for making flexible, corrugated rubber tubing with internal reinforcement. An extruded sleeve of uncured rubber is slid axially onto an elongated internal forming member, after which an external forming means is placed around the assembled sleeve and used to form corrugations. The resulting product is heat-treated to set the corrugations and thus to form a flexible cor-rugated tube length. A helix formed of flexible, resili-ent wire rod is pulled through the corrugated tubing in an axial direction and simultaneously rotated in a direc-tion to thread the helical rod into the internal hellcal groove in the sorrugated product. At the same time, the helix is axially extended to reduce its helix diameter.
When the helix has been completely extended through the corrugated tubing, it is released so that it expands radially into tight conformance with the internal helical groove.
Description
3~3 FLEXIBLE CORRUGATED RUBBER TUBING
WITH INTERVAL REINFORCE~._NT
BACKGROUND OF THE INVENTION
This invention relates to corrugated, flexible tubing, especially rubber tubing, including both the helically corrugated type of rubber tubing made using the "cording" method and apparatus disclosed in US. Patents Nos. 2,83~,096; 2,879,953; ~,888,712; 2,909,198;
3,155,757; and 3,635,255, and also the Lyre of helically corrugated tubing made using the "axially extensible helix method end apparatus of US. Patents Nos.
3,168,604; 3,334,581; 3,669,586; 3,705,780; 3,8Q9,522;
3~975,129; 4,053,275; 4,133~828; and 4,360,493.
More angularly the invention relates to a novel variation of the type of corrugated tubular product that may be maze using the basic concepts of the methods and apparatus referred to above, and espouse to a novel corrugated, tubular rubber product that has unique properties particularly suitable in special applications where internal reinforcement is required.
Flexible, helically corrugated rubber tubing of the type described is formed ox an extruded sleeve of vulcani2able material which, when cured, provides a home-generous, phlox, resilient wall structure. The result-in helically corrugated tube is flexible end still main-twins its tubular form in a semi-rigid condition.
As indicated above, in the past, corrugated, flexible tubing has been made using both the cording method and the "axially extensible helix" method both . .
`
~Z2~3~3 methods being described in detail in the aforementioned patents. Helically corrugated tubing made according to the "cording" method is made by first drawing an extruded sleeve of uncured rubber axially over an elongated, rotatable monocle with a core strip wrapped around it to form a single, continuous external thread. The uncured rubber sleeve us forced into the helical groove or root of the thread my a length of cord wrapped around the sleeve to impart a desired corrugated shape. The rubber sieve is cured in this condition, and the cord removed.
After curing, the resulting hose length may be removed from the mandrel and the core strip in a number of ways, such as by being blown off by air pressure prom within the mandrel as described in US. Patent 2,888,712.
Flexible corrugated tubing of the type to which the present invention is directed may also be produced using the taxi fly extensible helix" method, as indicated above. In accordance with this method, external forming devices having axially spaced helical convolutions are employed with c forming mandrel to produce embryonic eon-roguishness in uncured rubber sleeves. Each time a tube is wormed, the forming member is placed over the worming mandrel on which the uncured rubber sleeve has been post-toned, and the sleeve is radially expanded with air pressure prom within so that it bulges into the spaces between the helical convolutions, thus forming creases between the bulges. The external forming member and sleeve-are then collapsed axially so that the sleeve is axially compressed concertina fashion. The creases together with adjacent bulges, provide embryonic cargo-lions. Then toe forming member is axially extended together with the sleeve after which the sleeve is removed from tyke forming mandrel and placed on a .
93~3 cylindrical curing mandrel, where it is axially fore-shortened, concertina fashion, into corrugated form with the desired spacing between Addison helical corrugations.
The helical corrugations usually provide rlgidl-try in the tubing to prevent collapse, such so when the tubing is flexed around sharp bends. The rigidity, how-ever, is related to a great extent to the thickness of the wall of the tubing relative to the tube diameter.
Where the tube diameter is large relative to the wall thickness, the rigidity provided by the corrugations may not be sufficient to resist collapse under some circus-stances. In any event, neither of the above methods up to the present produces a product with sufficient rigidly try for some applications.
The method and product of the present invention, however resolve the difficulties indicated above and afford other features sod advantages heretofore no ox-trainable.
SUMMARY OF THE INVENTION
It is among the objects of the present invention to improve the strength and rigidity that can be obtained with flexible corrugstèd rubber tubing made in accord dance with the prior art "cording" method or the prior art laxly extensible helix" method.
Another object of the invention is to produce flexible, helically corrugated rubber tubing having on internal reinforcement.
~Z293~;~
In accordance with the invention, a flexible, helically corrugated length of tubing is produced using an extruded sly of uncured rubber. In the method ox the invention, the sleeve is positioned over an elongated internal forming member by sliding the sleeve over it in an axial dire ion. Then> an external corrugation form-in means is posi~ioned.around the sleeve and used to form a cargo Ed tubular element. The resulting product is then heat-t-eated to set the corrugations and Norm a flexible, corrugated tube length. Finally, an elongated helical length of relatively stiff, resilient wire rod having about the same helix outer diameter as the root diameter of the internal helical groove in the corrugated tube length is threaded into the internal helical groove. This -s accomplished by pulling the helix axis ally through the tube length while simultaneously rotate in the helix and extending it axially to reduce its helix diameter Once the helical rod length has been completely extended through the tube length, the rod is released, whereby it expands radically into tight conform-ante with the sternal groove.
BRIEF DESCRIPTION OF THE DR~WXNGS
FIG. 1 is a fragmentary elevation Al view with parts broken away, illustrating the construction of a flexible helically corrugated tube Length with internal reinforcement jade in accordance with tune present invent lion;
Flog 2 is a fragmentary, sectional view drawn Jo the same scale as FIG. 1 and taken on tune Noah 2-2 of FIG. i;
~2~3;~
FIG. 3 is a series of elevation Al views, include in views a through F, which illustrate in somewhat die-grammatic form the sequential steps of the method ox the invention; and FIG. 4 is a ~ragmen~ary9 sectional view on an enlarged scale, illustrating the forming of flexible, helically corrugated length of tubing in accordance with the "axially extensible external form" aspect of the method of the invention, with parts broken away and shown in section for the purpose of illustration.
.
DESCRIPTION OF THE PREFERRED EMBODIMENT
- Referring more particularly to the drawings, FIG. 1 shows a flexible, helically corrugated tube length 17 having external corrugations 22 and an internal hell-clue groove 21. A helix of flexible, resilient wire rod 23 is seated in the internal groove 21 to provide rein-for cement and resistance against collapse over and above what is provided by- the corrugations themselves.
FIG. 3 illustrates the method for making the product ox the invention using the cording method, and FIG. 4 illustrates reinforced tubing being produced in accordance with the "axially ex~enslble helix" method which will be only briefly described herein.
Referring to I 3, a length of corrugated tubing is furled from awl extruded sleeve of vulcanlzable stock, and subsequently provided with the flexible, resilient reinforcing helix 23.
~Z;~93~3 A tubular mandrel 10 is mounted it one end in rotary support 11 that supplies the rotary drive, and at the other end -n a removable idling rotary support 12.
An extruded sleeve 13 ox vulcaniz~ble stock is positioned over the mandrel 10. Then a cord 15 is wrapped around the assembly to press the extruded sleeve 13 into a heft-eel groove on the mandrel. This procedure is illustrated and described on greater detail in US. patent No.
WITH INTERVAL REINFORCE~._NT
BACKGROUND OF THE INVENTION
This invention relates to corrugated, flexible tubing, especially rubber tubing, including both the helically corrugated type of rubber tubing made using the "cording" method and apparatus disclosed in US. Patents Nos. 2,83~,096; 2,879,953; ~,888,712; 2,909,198;
3,155,757; and 3,635,255, and also the Lyre of helically corrugated tubing made using the "axially extensible helix method end apparatus of US. Patents Nos.
3,168,604; 3,334,581; 3,669,586; 3,705,780; 3,8Q9,522;
3~975,129; 4,053,275; 4,133~828; and 4,360,493.
More angularly the invention relates to a novel variation of the type of corrugated tubular product that may be maze using the basic concepts of the methods and apparatus referred to above, and espouse to a novel corrugated, tubular rubber product that has unique properties particularly suitable in special applications where internal reinforcement is required.
Flexible, helically corrugated rubber tubing of the type described is formed ox an extruded sleeve of vulcani2able material which, when cured, provides a home-generous, phlox, resilient wall structure. The result-in helically corrugated tube is flexible end still main-twins its tubular form in a semi-rigid condition.
As indicated above, in the past, corrugated, flexible tubing has been made using both the cording method and the "axially extensible helix" method both . .
`
~Z2~3~3 methods being described in detail in the aforementioned patents. Helically corrugated tubing made according to the "cording" method is made by first drawing an extruded sleeve of uncured rubber axially over an elongated, rotatable monocle with a core strip wrapped around it to form a single, continuous external thread. The uncured rubber sleeve us forced into the helical groove or root of the thread my a length of cord wrapped around the sleeve to impart a desired corrugated shape. The rubber sieve is cured in this condition, and the cord removed.
After curing, the resulting hose length may be removed from the mandrel and the core strip in a number of ways, such as by being blown off by air pressure prom within the mandrel as described in US. Patent 2,888,712.
Flexible corrugated tubing of the type to which the present invention is directed may also be produced using the taxi fly extensible helix" method, as indicated above. In accordance with this method, external forming devices having axially spaced helical convolutions are employed with c forming mandrel to produce embryonic eon-roguishness in uncured rubber sleeves. Each time a tube is wormed, the forming member is placed over the worming mandrel on which the uncured rubber sleeve has been post-toned, and the sleeve is radially expanded with air pressure prom within so that it bulges into the spaces between the helical convolutions, thus forming creases between the bulges. The external forming member and sleeve-are then collapsed axially so that the sleeve is axially compressed concertina fashion. The creases together with adjacent bulges, provide embryonic cargo-lions. Then toe forming member is axially extended together with the sleeve after which the sleeve is removed from tyke forming mandrel and placed on a .
93~3 cylindrical curing mandrel, where it is axially fore-shortened, concertina fashion, into corrugated form with the desired spacing between Addison helical corrugations.
The helical corrugations usually provide rlgidl-try in the tubing to prevent collapse, such so when the tubing is flexed around sharp bends. The rigidity, how-ever, is related to a great extent to the thickness of the wall of the tubing relative to the tube diameter.
Where the tube diameter is large relative to the wall thickness, the rigidity provided by the corrugations may not be sufficient to resist collapse under some circus-stances. In any event, neither of the above methods up to the present produces a product with sufficient rigidly try for some applications.
The method and product of the present invention, however resolve the difficulties indicated above and afford other features sod advantages heretofore no ox-trainable.
SUMMARY OF THE INVENTION
It is among the objects of the present invention to improve the strength and rigidity that can be obtained with flexible corrugstèd rubber tubing made in accord dance with the prior art "cording" method or the prior art laxly extensible helix" method.
Another object of the invention is to produce flexible, helically corrugated rubber tubing having on internal reinforcement.
~Z293~;~
In accordance with the invention, a flexible, helically corrugated length of tubing is produced using an extruded sly of uncured rubber. In the method ox the invention, the sleeve is positioned over an elongated internal forming member by sliding the sleeve over it in an axial dire ion. Then> an external corrugation form-in means is posi~ioned.around the sleeve and used to form a cargo Ed tubular element. The resulting product is then heat-t-eated to set the corrugations and Norm a flexible, corrugated tube length. Finally, an elongated helical length of relatively stiff, resilient wire rod having about the same helix outer diameter as the root diameter of the internal helical groove in the corrugated tube length is threaded into the internal helical groove. This -s accomplished by pulling the helix axis ally through the tube length while simultaneously rotate in the helix and extending it axially to reduce its helix diameter Once the helical rod length has been completely extended through the tube length, the rod is released, whereby it expands radically into tight conform-ante with the sternal groove.
BRIEF DESCRIPTION OF THE DR~WXNGS
FIG. 1 is a fragmentary elevation Al view with parts broken away, illustrating the construction of a flexible helically corrugated tube Length with internal reinforcement jade in accordance with tune present invent lion;
Flog 2 is a fragmentary, sectional view drawn Jo the same scale as FIG. 1 and taken on tune Noah 2-2 of FIG. i;
~2~3;~
FIG. 3 is a series of elevation Al views, include in views a through F, which illustrate in somewhat die-grammatic form the sequential steps of the method ox the invention; and FIG. 4 is a ~ragmen~ary9 sectional view on an enlarged scale, illustrating the forming of flexible, helically corrugated length of tubing in accordance with the "axially extensible external form" aspect of the method of the invention, with parts broken away and shown in section for the purpose of illustration.
.
DESCRIPTION OF THE PREFERRED EMBODIMENT
- Referring more particularly to the drawings, FIG. 1 shows a flexible, helically corrugated tube length 17 having external corrugations 22 and an internal hell-clue groove 21. A helix of flexible, resilient wire rod 23 is seated in the internal groove 21 to provide rein-for cement and resistance against collapse over and above what is provided by- the corrugations themselves.
FIG. 3 illustrates the method for making the product ox the invention using the cording method, and FIG. 4 illustrates reinforced tubing being produced in accordance with the "axially ex~enslble helix" method which will be only briefly described herein.
Referring to I 3, a length of corrugated tubing is furled from awl extruded sleeve of vulcanlzable stock, and subsequently provided with the flexible, resilient reinforcing helix 23.
~Z;~93~3 A tubular mandrel 10 is mounted it one end in rotary support 11 that supplies the rotary drive, and at the other end -n a removable idling rotary support 12.
An extruded sleeve 13 ox vulcaniz~ble stock is positioned over the mandrel 10. Then a cord 15 is wrapped around the assembly to press the extruded sleeve 13 into a heft-eel groove on the mandrel. This procedure is illustrated and described on greater detail in US. patent No.
2,832,096. When the assembly has been generally formed, the mandrel 10, together with the sleeve 13 and cord lo, is removed Roy the rotary supports 11 and 12 and placed in a curing oven The helical thread on the mandrel 10 for the extruded sleeve 13 may be formed, for example, by wrap-ping a strip I of relatively hard, flexible rubber around the mandrel 10 to define a single thread ox unit form pitch. Tao core strip 20 has a central ridge that forms the helical crest of the thread and its sides abut one another to define the helical root The procedure : - for oiling the flexibly corrugated hose length is best illustrated sequentially in FIG. 5. The extruded sleeve 13 of vulcanizcble stock is slid axially over theism-bled mandrel 10 and core strip I It will be noted what during the positioning of the sleeve 13, the mandrel I
is supported it calltilever fashion by the rotary support 11, and air under pressure to facilitate the sliding of the sleeve in on axial direction is supplied through the rotary support 11.
When toe sleeve 13 is properly positioned on the mandrel, as Chicano in FIG. aye, the cord 15 is wrapped around the sleeve as indicated in FIG. Jo The cord 15 is wrapped under tension with successive turns thereof in spaced, parallel relation, and located in the helical ~lZ~9;3~
length as the corrugated tube length 17, and also approx-irately the save helix diameter as the root diameter of the internal ova formed in the tube length 17. Then, a pulling tool 25 is extender through the tube length 17 and latched into engagement with an end of the wire rod helix. The lo mint member is then dry axially through the tube length and at the same time rotated in drake-lion to thread the helix into the internal groove. At-the some time, the helix is axially extended somewhat to reduce its outer diameter and thus permit it to move through the groove with a minimum of friction. After the helix has been completely advanced through-the tube length, the tool is released to permit the helix to expand r~diall3 as it returns to its unstressed condition so that the helical convolutions expand radially into tight conformance with the internal helical groove.
FIG. 4 illustrates the principles embodying the method of the invention, but wherein the tubing is made in accordance with the prior art "axially extensible helix" method. In accordance with that method the extruded sleeve 32 is placed on a cylindrical mandrel 33, a helical external form 34 is placed over the sleeve 32, and elf under pressure is introduced through the ports 35 in the mandrel 33 to inflate the tube and form bulges 36 between the convolutions of the helical external forming member 34. Then, the helical forming member 34 is axial-lye collapsed to squeeze the bulges 36 between the convoy lotions and form embryonic-corrugations. The resulting assembly is disassembled by removing the external forming member 34 and the sleeve 32 from the mandrel 33, aster which the preformed sleeve is placed on a curing mandrel, axially compressed to the desired shape, and cured in curing oven.
.
~2;~:9~3 grooves ox the mandrel assembly to press adjacent port lions of the sleeve 13 into the grooves. During the wrapping or "cording" process, the outer end of the mandrel 10 is placed in an idling rotary support 12, and the mandrel is rotated to wind or wrap the cord in a desired fashion.
Once the wrapping is completed, the tail end of the cord 15 is secured to the mandrel 10 and the result-in assembly 16 is removed from the rotary supports if and I and placed in a curing oven (FIG. Sac).
In the Turing ox the tubing, the tightly wound cord 15 maintains compressive radial forces on the sleeve and, in effect, forms an external mold which confines the rubber during curing. The softening of the rubber sleeve 13 by the curing heat causes the rubber to slow into and take the shape ox the helical groove formed in the man-duel assembly. The curing of the rubber while thus con-wined by the cord results in the formation ox a length of corrugated tubing.
After the assembly 16, including the cured eon-rugated tube length 17, is removed from the heat treating oven and cooled, the assembly is placed with the ends of the mandrel 10 supported by the rotary supports 11 and 12, and the mandrel is rotated while the cord 15 is us-wrapped from the Assembly, as illustrated in FIG. I.
When the unwrapping is completed, air under pressure is supplied to the space between the outer surface of the mandrel 10 and the inner surface of the corrugated tube length 17, and the tube is slid axially of the mandrel.
The resulting product produced by the method described is then provided with an internal reinforcement in the lot-lowing manner A helix or helical length ox ~lexib~e, resilient rod 23 is formed to have approximately the save .
~293: Lo The resulting product is then provided with the internal reinforcing helix 23 in the same manner described above in connection with the "cording" method.
While the method of the invention has been illustrated and described with respect to a specific .
- embodiment thereof, this is intended for the purpose of illustration rather than limitation, and other variations and modi~lcations of the specific method heroin shown and described will be apparent to those skilled in the art, all within the intended spirit and scope of the invent Zion. Accordingly, the patent is not to be limited in scope and effect to the specific embodiment herein shown and described, nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.
.
is supported it calltilever fashion by the rotary support 11, and air under pressure to facilitate the sliding of the sleeve in on axial direction is supplied through the rotary support 11.
When toe sleeve 13 is properly positioned on the mandrel, as Chicano in FIG. aye, the cord 15 is wrapped around the sleeve as indicated in FIG. Jo The cord 15 is wrapped under tension with successive turns thereof in spaced, parallel relation, and located in the helical ~lZ~9;3~
length as the corrugated tube length 17, and also approx-irately the save helix diameter as the root diameter of the internal ova formed in the tube length 17. Then, a pulling tool 25 is extender through the tube length 17 and latched into engagement with an end of the wire rod helix. The lo mint member is then dry axially through the tube length and at the same time rotated in drake-lion to thread the helix into the internal groove. At-the some time, the helix is axially extended somewhat to reduce its outer diameter and thus permit it to move through the groove with a minimum of friction. After the helix has been completely advanced through-the tube length, the tool is released to permit the helix to expand r~diall3 as it returns to its unstressed condition so that the helical convolutions expand radially into tight conformance with the internal helical groove.
FIG. 4 illustrates the principles embodying the method of the invention, but wherein the tubing is made in accordance with the prior art "axially extensible helix" method. In accordance with that method the extruded sleeve 32 is placed on a cylindrical mandrel 33, a helical external form 34 is placed over the sleeve 32, and elf under pressure is introduced through the ports 35 in the mandrel 33 to inflate the tube and form bulges 36 between the convolutions of the helical external forming member 34. Then, the helical forming member 34 is axial-lye collapsed to squeeze the bulges 36 between the convoy lotions and form embryonic-corrugations. The resulting assembly is disassembled by removing the external forming member 34 and the sleeve 32 from the mandrel 33, aster which the preformed sleeve is placed on a curing mandrel, axially compressed to the desired shape, and cured in curing oven.
.
~2;~:9~3 grooves ox the mandrel assembly to press adjacent port lions of the sleeve 13 into the grooves. During the wrapping or "cording" process, the outer end of the mandrel 10 is placed in an idling rotary support 12, and the mandrel is rotated to wind or wrap the cord in a desired fashion.
Once the wrapping is completed, the tail end of the cord 15 is secured to the mandrel 10 and the result-in assembly 16 is removed from the rotary supports if and I and placed in a curing oven (FIG. Sac).
In the Turing ox the tubing, the tightly wound cord 15 maintains compressive radial forces on the sleeve and, in effect, forms an external mold which confines the rubber during curing. The softening of the rubber sleeve 13 by the curing heat causes the rubber to slow into and take the shape ox the helical groove formed in the man-duel assembly. The curing of the rubber while thus con-wined by the cord results in the formation ox a length of corrugated tubing.
After the assembly 16, including the cured eon-rugated tube length 17, is removed from the heat treating oven and cooled, the assembly is placed with the ends of the mandrel 10 supported by the rotary supports 11 and 12, and the mandrel is rotated while the cord 15 is us-wrapped from the Assembly, as illustrated in FIG. I.
When the unwrapping is completed, air under pressure is supplied to the space between the outer surface of the mandrel 10 and the inner surface of the corrugated tube length 17, and the tube is slid axially of the mandrel.
The resulting product produced by the method described is then provided with an internal reinforcement in the lot-lowing manner A helix or helical length ox ~lexib~e, resilient rod 23 is formed to have approximately the save .
~293: Lo The resulting product is then provided with the internal reinforcing helix 23 in the same manner described above in connection with the "cording" method.
While the method of the invention has been illustrated and described with respect to a specific .
- embodiment thereof, this is intended for the purpose of illustration rather than limitation, and other variations and modi~lcations of the specific method heroin shown and described will be apparent to those skilled in the art, all within the intended spirit and scope of the invent Zion. Accordingly, the patent is not to be limited in scope and effect to the specific embodiment herein shown and described, nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.
.
Claims (6)
1. A method for making flexible corrugated rub-ber tubing with reinforced helical corrugations compris-ing the steps of:
(a) forming helical corrugations in an elongated uncured rubber sleeve to define a helical internal groove, (b) heat-treating said rubber sleeve to set said corrugations and form a flexible length of corrugated rubber tubing with a helical internal groove, (c) forming a helix of relatively stiff resilient wire rod having about the same helix outer diameter as the root diameter of said internal helical groove, (d) pulling said wire helix axially through said length of rubber tubing while simultane-ously rotating said helix relative to said length to extend said helix and cause a reduc-tion in the diameter thereof, and to thread said helix into said helical groove, and (e) thereafter releasing said helix whereby said helix expands radially into tight conform ance with said groove.
(a) forming helical corrugations in an elongated uncured rubber sleeve to define a helical internal groove, (b) heat-treating said rubber sleeve to set said corrugations and form a flexible length of corrugated rubber tubing with a helical internal groove, (c) forming a helix of relatively stiff resilient wire rod having about the same helix outer diameter as the root diameter of said internal helical groove, (d) pulling said wire helix axially through said length of rubber tubing while simultane-ously rotating said helix relative to said length to extend said helix and cause a reduc-tion in the diameter thereof, and to thread said helix into said helical groove, and (e) thereafter releasing said helix whereby said helix expands radially into tight conform ance with said groove.
2. A flexible, corrugated rubber tube made in accordance with the process of claim l.
3. A method as described in claim 1, wherein said helical corrugations are formed by:
positioning said uncured rubber sleeve over an elongated internal forming member having a helical surface formed with a helical ridge and a helical groove;
and wrapping a flexible element about said sleeves under tension with successive turns of said ele-ment in spaced, generally parallel relation and in the helical groove of said internal forming member to press adjacent portions of said sleeve with the groove of said internal forming member.
positioning said uncured rubber sleeve over an elongated internal forming member having a helical surface formed with a helical ridge and a helical groove;
and wrapping a flexible element about said sleeves under tension with successive turns of said ele-ment in spaced, generally parallel relation and in the helical groove of said internal forming member to press adjacent portions of said sleeve with the groove of said internal forming member.
4. A flexible, corrugated rubber tube made in accordance with the process of claim 3.
5. A method as described in claim 1, wherein said helical corrugations are formed by:
positioning an extruded sleeve of uncured rubber on a forming mandrel by sliding said sleeve in an axial direction over said mandrel;
placing an external, collapsible helical form around said sleeve to define helical convolutions;
expanding said sleeve radially to form radial bulges between said convolutions;
axially foreshortening said sleeve and said helical form to form embryonic corrugations in said sleeves;
(claim 5 continued) thereafter axially extending said sleeve and said helical form and removing said sleeve from said forming mandrel; and thereafter placing said sleeve on a separate curing mandrel in an axially foreshortened corrugated condition.
positioning an extruded sleeve of uncured rubber on a forming mandrel by sliding said sleeve in an axial direction over said mandrel;
placing an external, collapsible helical form around said sleeve to define helical convolutions;
expanding said sleeve radially to form radial bulges between said convolutions;
axially foreshortening said sleeve and said helical form to form embryonic corrugations in said sleeves;
(claim 5 continued) thereafter axially extending said sleeve and said helical form and removing said sleeve from said forming mandrel; and thereafter placing said sleeve on a separate curing mandrel in an axially foreshortened corrugated condition.
6. A flexible, corrugated rubber tube made in accordance with the process of claim 5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US66535084A | 1984-10-26 | 1984-10-26 | |
| US665,350 | 1984-10-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1229313A true CA1229313A (en) | 1987-11-17 |
Family
ID=24669765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000482823A Expired CA1229313A (en) | 1984-10-26 | 1985-05-30 | Flexible corrugated rubber tubing with internal reinforcement |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1229313A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7891382B2 (en) | 2005-12-16 | 2011-02-22 | Mercury Plastics, Inc. | Overmolded and bendable position-retaining tubing |
-
1985
- 1985-05-30 CA CA000482823A patent/CA1229313A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7891382B2 (en) | 2005-12-16 | 2011-02-22 | Mercury Plastics, Inc. | Overmolded and bendable position-retaining tubing |
| US8454874B2 (en) | 2005-12-16 | 2013-06-04 | Mercury Plastics, Inc. | Method for insert molding bendable position-retaining tubing |
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