Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Longitudinally progressive helical winding means
Patent
1994-11-21
1997-01-14
Johnstone, Adrienne C.
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Longitudinally progressive helical winding means
156189, 156195, 15624415, 156498, 425366, 425369, B29C 4788, B29C 5322, B29C 5362, B29C 5372
Patent
active
055935354
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an apparatus for producing a corrugated tube of synthetic resin. More particularly, it relates to an apparatus for producing a corrugated tube in which the cross-sectional shape of the outer circumferential surface of the tube is corrugated and which exhibits good flattening strength and especially high molding stability and high durability.
BACKGROUND TECHNOLOGY
Various proposals have hitherto been made for an apparatus for producing a corrugated tube of synthetic resin so that the outer circumferential surface of the tube has a corrugated cross-sectional profile. For example, there is known an apparatus comprising a roller assembly made up of plural rollers forming an imaginary cylinder, the rollers being each provided with plural convexed rings of the same size, and being rotated about their own axes at equal speed. The rollers are arranged parallel to one another so that the axes of the rollers are on the circumference surface of the imaginary cylinder and. The axial directions of the rollers are circumferentially inclined and parallel to one another. A die is provided for continuously supplying a strip of synthetic resin in a molten state from the lateral side onto the periphery of the roller assembly. A driving motor continuously rotates the rollers at equal speed. There is also known an apparatus (Japanese Patent Publication No. 62-60261 (1987)) which further comprises a pressure roller profiled for meshing with the profile of the outer wall surface of each roller for fixing the shape of the strip of synthetic resin, means for cooling the synthetic resin as it is shaped to a tubular profile as it is moved along the outer periphery of the imaginary cylinder, and forming means for forming a smooth cylindrical-shaped synthetic resin on the inner side of the corrugated tube for providing a double-walled structure.
However, with the above-described known apparatuses, as the strip of synthetic resin is wound spirally and advanced along the axis of the roller assembly while being cooled and cured, the strip itself contracts in size due to cooling. Since the convexed rings formed on each roller are of the same size and arrayed at an equal interval on the roller, the synthetic resin strip is actually being cured under conditions in which the strip is pulled outwardly along the shape of each convexed ring. The result is that, as the strip of synthetic resin progresses axially along the roller assembly, the strip tends to be detached from the valley portions between the convexed rings to detract from molding stability, accuracy and durability of the ultimate corrugated tube.
Besides, with the above-described known apparatus, although each roller of the roller assembly is rotated at equal speed, a difference in circumferential speed of about 10 to 45% is produced between (a) circumferential speed at the apex of the convexed portion and (b) speed in the recessed interstices between neighboring convexed portions of each roller, so that longitudinal creases (internal strain) are produced between the convexed portions and the recessed valley portions of the wall surfaces of the corrugated tube. As a result, the corrugated tube produced is lowered in durability, such as by reduced impact strength or pressure resistance.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide an apparatus for producing a corrugated tube which is capable of preventing a strip of synthetic resin from being detached from the rollers due to contraction in size and which is superior in durability, such as by increased impact strength or pressure resistance.
It is another object of the present invention to provide an apparatus for producing a corrugated tube which is superior in durability, such as by increased impact strength or pressure resistance and in which longitudinal creases (internal strain) between the convexed portions and the valley portions thereof are not formed.
According to the present invention, there is provided an apparatus for producing a corrugate
REFERENCES:
patent: 2398876 (1946-04-01), Bailey
patent: 3532580 (1970-10-01), Kanao
patent: 4292113 (1981-09-01), Hirata
patent: 4575400 (1986-03-01), Ueda et al.
Hasegawa Noboru
Kagabu, deceased Mitsuo
Kagabu, heir Setsu
Johnstone Adrienne C.
Toyo Chemical Co., Ltd.
LandOfFree
Apparatus for producing corrugated tube does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for producing corrugated tube, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for producing corrugated tube will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1385309