US3763681A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tube formation and products formed thereby
Assignee: Individual
•
Filing: 1972-05-22
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Granted: 1973-10-09
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Expires: 1992-05-22
Abstract
Abstract A method of forming thin walled ductile tubes by wetting the inside of a thick walled tube with a liquid and passing the tube between rollers to flatten the tube and simultaneously elongating the tube and reducing the wall thickness thereof, and then applying pressure to the inside of the tube to restore a tubular shape, the tube being preformed into a radiator core or the like prior to the application of pressure and stretched to avoid wrinkling.
Inventors
- 👤 W Flintoft
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:47
CPC Classifications
F; F28; F28D; F28D1/00; F28D1/02; F28D1/04; F28D1/047; F28D1/0477; B; B21; B21B; B21B23/00; B21C; B21C37/00; B21C37/06; B21C37/14; B21C37/15; B21D; B21D53/00; B21D53/02; B21D53/08; B21D53/085; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
165 words
Improvements in a method of tube formation wherein thin walled ductile tubes are formed by the steps of a. wetting the inside of a thick walled tube with a liquid such as a soluble oil, b. passing the tube between rollers in a longitudinal direction of the tube a number of times while maintaining sufficient pressure on the rollers to flatten the tube and simultaneously elongating the tube and reducing the wall thickness thereof during each pass, c. annealing the tube between passes, d. bending the flattened tube about a generally transverse axis before placing it into a hollow die having a cavity greater than the thickness of the flattened tube but to limit expansion of the tube, e. stretching the tube in the said die to force the inside of the bent portions against the die, and f. then expanding the tube into the die by applying pressure to the inside of the said tube, whereby significant wrinkling of the bent portions is avoided.
Claim 2
Dependent Claim
165 words
Improvements in a method of tube formation wherein thin walled ductile tubes are formed by the steps of a. wetting the inside of a thick walled tube with a liquid such as a soluble oil, b. passing the tube between rollers in a longitudinal direction of the tube a number of times while maintaining sufficient pressure on the rollers to flatten the tube and simultaneously elongating the tube and reducing the wall thickness thereof during each pass, c. annealing the tube between passes, d. bending the flattened tube about a generally transverse axis before placing it into a hollow die having a cavity greater than the thickness of the flattened tube but to limit expansion of the tube, e. stretching the tube in the said die to force the inside of the bent portions against the die, and f. then expanding the tube into the die by applying pressure to the inside of the said tube, whereby significant wrinkling of the bent portions is avoided.
Claim 3
Dependent Claim
135 words
Improvements in the tube formation method according to claim 1 including the steps of bending the flattened tube about a generally transverse axis at a number of spaced localities to form substantially parallel sections joined by bends, and the said tube is placed into a cavity, formed in a two-part die having fingers defining the cavity, the ends of the said fingers at least nearly engaging the insides of said bends, one part of the die being movable relatively toward the other whereby when said one die part is moved the flattened tube is stretched to give firm engagement of the fingers with the inside of the said bends, such relative movement of said one die part leaving a cavity into which the tube can be expanded when the pressure is applied within the tube.
Claim 4
Dependent Claim
132 words
Improvements in tube formation wherein thin walled ductile tubes are formed by passing the tube lengthwise between rollers to flatten and elongate the tube by reducing the wall thickness, then bending the flattened tube about generally transverse axes to form a heat exchanger core, placing the so formed tube into a die having a cavity greater than the thickness of the flattened tube but to limit expansion of the tube, applying a stretching force to the said tube while in said die to force the inside of the bends so formed against the die, then expanding the inside of the said tube by applying fluid pressure within the said tube to force the walls of the said tube to conform to the said die, whereby significant wrinkling of the bends is avoided.
Claim 5
Dependent Claim
132 words
Improvements in tube formation wherein thin walled ductile tubes are formed by passing the tube lengthwise between rollers to flatten and elongate the tube by reducing the wall thickness, then bending the flattened tube about generally transverse axes to form a heat exchanger core, placing the so formed tube into a die having a cavity greater than the thickness of the flattened tube but to limit expansion of the tube, applying a stretching force to the said tube while in said die to force the inside of the bends so formed against the die, then expanding the inside of the said tube by applying fluid pressure within the said tube to force the walls of the said tube to conform to the said die, whereby significant wrinkling of the bends is avoided.
Claim 6
Dependent Claim
118 words
Improvements in tube formation according to claim 3 wherein the flattened tube is Bent about a generally transverse axis at a number of spaced localities to form substantially parallel sections joined by bends, and the said tube is placed into a cavity formed in a two-part die having fingers defining the cavity, the ends of the said fingers at least nearly engaging the insides of said bends, whereby when one part of the die is moved relatively toward the other, the flattened tube is stretched to give firm engagement of the fingers with the inside of the said bends but leave a cavity into which the tube can be expanded when the pressure is applied within the tube.
Claim 7
Dependent Claim
139 words
A machine for use in tube formation wherein pre-flattened tube which is bent about a generally transverse axis to comprise a series of parallel sections joined by bends, placing the so formed tube into a die having a cavity greater than the thickness of the flattened tube but to limit expansion of the tube, which machine comprises a pair of dies forming between them a cavity to receive the said flat shaped tube, means to move one die relative to the other to stretch the said tube by engagement of die members with the inside of the bends, and means to expand the said tube comprising clamp means to seal one end of the tube, and pressure applying means to engage the other end of the tube and apply pressure thereinto to expand the said tube into said die.
Claim 8
Dependent Claim
139 words
A machine for use in tube formation wherein pre-flattened tube which is bent about a generally transverse axis to comprise a series of parallel sections joined by bends, placing the so formed tube into a die having a cavity greater than the thickness of the flattened tube but to limit expansion of the tube, which machine comprises a pair of dies forming between them a cavity to receive the said flat shaped tube, means to move one die relative to the other to stretch the said tube by engagement of die members with the inside of the bends, and means to expand the said tube comprising clamp means to seal one end of the tube, and pressure applying means to engage the other end of the tube and apply pressure thereinto to expand the said tube into said die.
Claim 9
Dependent Claim
118 words
A machine according to claim 5 wherein the dies each comprise fingers forming between them recesses, the fingers of one die filling into the recesses within the other die to define around the fingers the cavity into which the tube is to be expanded, said fingers being movable longitudinally in said recesses whereby the bent tube can be stretched when one part of the die is moved relatively toward the other die, said stretch causing firm engagement of the ends of the fingers with the inside of the said bends of the tube so that when pressure is applied within the tube the flattened tube will be expanded into a hollow tube in the cavity without significant wrinkling.
Claim 10
Dependent Claim
114 words
A machine according to claim 5 in which each die comprises fingers forming between their recesses, said fingers being formed by replaceable plates secured to a support, the inner ends of said plates being adapted to engage the inside of bends of the said flattened tube, bend forming blocks between the said plates of one die to form adjustable ends of that die, bend forming portions between the plates of the other said die to form adjustable ends of that die, and means on the said dies to clamp shut one end of the said flattened tube and to clamp said other end to a fluid supplying nozzle whereby said flattened tube is expanded.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |