Patent US3739615A successfully refreshed from Google Patents.
US3739615A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making wrinkle-free thin-walled coiled tubing
Assignee: Individual
•
Filing: 1971-06-01
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Granted: 1973-06-19
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Expires: 1991-06-01
Abstract
Abstract A method of coiling thin-walled tubing into a small diameter coil free of wrinkles or distortion from end to end thereof. Tubing of the required length is maintained pressurized with liquid to substantially the yield point of the material thereby placing the tube wall in high tensile stress longitudinally and circumferentially and maintaining the tubing straight until it is progressively formed into a coil without the use of clamps, dies or tools other than a rotary mandrel. The method technique permits the formation of multiple layer coils using an inner layer to support the formation of a second layer of convolutions.
Inventors
- 👤 R Tressel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:44
CPC Classifications
B; B21; B21D; B21D9/00; B21D9/15; B21C; B21C37/00; B21C37/06; B21C37/15; B21D11/00; B21D11/06; B21F; B21F3/00; B21F3/02; B21F3/04; Y; Y10; Y10S; Y10S72/00; Y10S72/701
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
195 words
That method of constructing a multi-layer coil of circular thin-walled tubing having a wall thickness not substantially in excess of one tenth of its OD without forming wrinkles and partial flattening which comprises: closing off one end of the tubing, anchoring the closed end of said tubing to a rotary mandrel having an OD corresponding to the ID of the tubing coil under construction, charging the interior of the tubing with pressurized liquid to substantially the yield point notwithstanding an increase in the volumetric capacity of the tubing as it elongates during coiling on said mandrel, utilizing the highly pressurized liquid charge to hold said tubing straight and in high tension longitudinally and circumferentially thereof, rotating said mandrel while supporting said tubing on a surface spaced from one side of the mandrel until a desired number of convolutions have been formed, and adding pressurized liquid in communication with constant pressure maintaining means to said tubing as it is being coiled to maintain the liquid pressure substantially constant at a value close to the yield point of the tubing notwithstanding an increase in the volumetric capacity thereof as the tubing elongates during coiling about said mandrel.
Claim 2
Dependent Claim
195 words
That method of constructing a multi-layer coil of circular thin-walled tubing having a wall thickness not substantially in excess of one tenth of its OD without forming wrinkles and partial flattening which comprises: closing off one end of the tubing, anchoring the closed end of said tubing to a rotary mandrel having an OD corresponding to the ID of the tubing coil under construction, charging the interior of the tubing with pressurized liquid to substantially the yield point notwithstanding an increase in the volumetric capacity of the tubing as it elongates during coiling on said mandrel, utilizing the highly pressurized liquid charge to hold said tubing straight and in high tension longitudinally and circumferentially thereof, rotating said mandrel while supporting said tubing on a surface spaced from one side of the mandrel until a desired number of convolutions have been formed, and adding pressurized liquid in communication with constant pressure maintaining means to said tubing as it is being coiled to maintain the liquid pressure substantially constant at a value close to the yield point of the tubing notwithstanding an increase in the volumetric capacity thereof as the tubing elongates during coiling about said mandrel.
Claim 3
Dependent Claim
39 words
That method defined in claim 1 characterized in the step of anchoring the closed end of said tubing interiorly of the outer surface of mandrel surface and against a surface merging arcuately with the exterior of the mandrel surface.
Claim 4
Dependent Claim
102 words
That method defined in claim 1 characterized in the steps of placing a wedge-shaped semi-circular transition member against said mandrel with the pointed end thereof beneath the end of the last convolution of the tubing for use as a ramp to support the tubing while in transition between the last convolution of the first layer of convolutions and the first convolution of a second layer of convolutions, continuing to form a second layer of convolutions directly against said first layer, and releasing the pressure on the liquid in said tubing after completing said second layer and withdrawing the same from said mandrel.
Claim 5
Dependent Claim
83 words
The method defined in claim 3 characterized in the step of providing the portion of said mandrel closely beside the first convolution of tubing with an arcuate support for the last convolution of said second layer of tubing which arcuate support includes an arcuate surface of smaller radius than the radius of said second layer and merging tangentially with a straight surface whereby the outer terminal end of said second layer lies inwardly of the OD of said multi layer coil of tubing.
Claim 6
Dependent Claim
56 words
The method defined in claim 4 characterized in the step of anchoring the closed end of said tubing interiorly of the mandrel surface and against a surface merging smoothly with the exterior surface of the mandrel whereby both ends of said multi-layer coil of tubing lie inwardly of the OD''s of both layers of said coil.
Claim 7
Dependent Claim
24 words
The method defined in claim 1 characterized in the step of forming each convolution of said coil in close proximity to the preceding convolution.
Claim 8
Dependent Claim
49 words
The method defined in claim 3 characterized in the step of forming each convolution of said first layer of tubing in side by side contact with one another and with the convolutions of said second layer in direct contact with one another and with said first layer of convolutions.
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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |