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US3768291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming spiral ridges on the inside diameter of externally finned tube
Assignee: Bank of Nova Scotia
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Filing: 1972-02-07
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Granted: 1973-10-30
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Expires: 1992-02-07
Abstract
Abstract Helical external fins and helical internal ridges are formed simultaneously on a tube by rolling the fins up out of the tube with inclined rotating discs, and pressing the tube onto a rotatable spirally or helically grooved portion of a multiple part internal pin.
Inventors
- 👤 K Rieger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:47
CPC Classifications
B; B21; B21C; B21C37/00; B21C37/06; B21C37/15; B21C37/20; B21C37/207; F; F28; F28F; F28F1/00; F28F1/10; F28F1/42; F28F1/422
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
246 words
Apparatus for simultaneously forming external helical fins and internal helical ridges which comprises means for supporting a tube for axial advance including internal tube support structure having a first part provided with a smooth cylindrical exterior surface and a second part provided with a helically grooved exterior surface, means for retaining said tube support structure at a fixed rolling zone longitudinally of the tube through which the tube advances, a plurality of circumferentially spaced fin rolling tools at said zone, each of said tools comprising a plurality of axially spaced groups of fin rolling discs, means supporting said tools for rotation with their axes crossed in space with respect to the tube axis, means supporting said first part of the tube support structure within the tube in registration with a first one of said groups of discs of said tools and supporting said second part of the tube support structure within the tube in registration with a second one of said group of discs of said tools positioned to act on the tube subsequent to the action thereon of said first one group of discs, means for effecting relative motion between said tools and tube equivalent to revolving said tools about the axis of the tube at said rolling zone and rotating said groups of discs about their own axes whereby to advance the tube through the rolling zone, and means providing for relative rotation between said first and second parts of said tube support structure.
Claim 2
Dependent Claim
246 words
Apparatus for simultaneously forming external helical fins and internal helical ridges which comprises means for supporting a tube for axial advance including internal tube support structure having a first part provided with a smooth cylindrical exterior surface and a second part provided with a helically grooved exterior surface, means for retaining said tube support structure at a fixed rolling zone longitudinally of the tube through which the tube advances, a plurality of circumferentially spaced fin rolling tools at said zone, each of said tools comprising a plurality of axially spaced groups of fin rolling discs, means supporting said tools for rotation with their axes crossed in space with respect to the tube axis, means supporting said first part of the tube support structure within the tube in registration with a first one of said groups of discs of said tools and supporting said second part of the tube support structure within the tube in registration with a second one of said group of discs of said tools positioned to act on the tube subsequent to the action thereon of said first one group of discs, means for effecting relative motion between said tools and tube equivalent to revolving said tools about the axis of the tube at said rolling zone and rotating said groups of discs about their own axes whereby to advance the tube through the rolling zone, and means providing for relative rotation between said first and second parts of said tube support structure.
Claim 3
Dependent Claim
35 words
Apparatus as defined in claim 1 in which said internal tube support structure comprises a mandrel, and said second part of said tube support structure comprises an externally grooved sleeve rotatably supported on said mandrel.
Claim 4
Dependent Claim
41 words
Apparatus as defined in claim 2 in which said first part of said tube support structure comprises a sleeve having a smooth cylindrical surface rotatably supported on said mandrel for rotation independent of said second part of said tube support structure.
Claim 5
Dependent Claim
32 words
Apparatus as defined in claim 3 in which the means for retaining the tube support structure at said fixed rolling zone comprises means providing for rotation of said mandrel about its axis.
Claim 6
Dependent Claim
50 words
Apparatus as defined in claim 2 in which said first part of said tube support structure comprises an integral part of said mandrel, and in which the means for retaining the tube support structure at said fixed rolling zone comprises means providing for rotation of said mandrel about its axis.
Claim 7
Dependent Claim
121 words
Apparatus for simultaneously forming external helical fins and internal helical ridges on a tube comprising a plurality of fin forming tools positioned circumferentially around a tube at a rolling zone, a tube support member within the tube at said rolling zone, means supporting said tube support member at said zone against axial movement and for rotation relative to the tube, said tube support member having helical grooves in its exterior surface into which said tools press material of the tube incident to the pressure applied to the tube in the fin forming operation, said grooves in normal cross-section having side walls which are essentially straight throughout their major width, the included angle between the side walls of said grooves being obtuse.
Claim 8
Dependent Claim
121 words
Apparatus for simultaneously forming external helical fins and internal helical ridges on a tube comprising a plurality of fin forming tools positioned circumferentially around a tube at a rolling zone, a tube support member within the tube at said rolling zone, means supporting said tube support member at said zone against axial movement and for rotation relative to the tube, said tube support member having helical grooves in its exterior surface into which said tools press material of the tube incident to the pressure applied to the tube in the fin forming operation, said grooves in normal cross-section having side walls which are essentially straight throughout their major width, the included angle between the side walls of said grooves being obtuse.
Claim 9
Dependent Claim
21 words
Apparatus as defined in claim 6 in which the included angle between the side waLls of said grooves is between 90120*.
Claim 10
Dependent Claim
48 words
Apparatus as defined in claim 6 in which the side wall of said groove facing in the direction from which the tube advances over the tube support member intersects the plane tangent to the tube support member thereat at a larger angle than does the opposite side wall.
Claim 11
Dependent Claim
39 words
Apparatus as defined in claim 6 in which said member is provided with grooves which extend therein at a helix angle in excess of 30*, an angle measured between the tube axis and a tangent to the helix curve.
Claim 12
Dependent Claim
23 words
Apparatus as defined in claim 6 in which the tube support member is formed of a hard, wear-resistant material such as tungsten carbide.
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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |