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US3820374A
Expired / Lapsed
US
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Mandrel for extruding tubing
Assignee: Dow Chemical Co
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Filing: 1972-03-24
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Granted: 1974-06-28
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Expires: 1992-03-24
Abstract
Abstract A mandrel and mandrel-dummy block assembly for extrusion of tubing is disclosed wherein the mandrel has a shaft cross sectional area so related to the working section cross sectional area that the mandrel will stay in place without attachment to the dummy block. Such mandrel reduces the problems of mandrel necking down and breakage.
Inventors
- 👤 K Braeuninger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:03
CPC Classifications
B; B21; B21C; B21C26/00; B21C25/00; B21C25/04; B29; B29C; B29C48/00; B29C48/25; B29C48/36; B29C48/475; B29C48/03; B29C48/09
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
96 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section; and b. a pivotable mandrel placed in said socket, said mandrel having a working section and a shaft section wherein the shaft cross sectional area is about equal to A2S/P1 + A2 where A2 is the average cross sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
Claim 2
Dependent Claim
96 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section; and b. a pivotable mandrel placed in said socket, said mandrel having a working section and a shaft section wherein the shaft cross sectional area is about equal to A2S/P1 + A2 where A2 is the average cross sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
Claim 3
Dependent Claim
42 words
The assembly of claim 1 wherein the working section of the mandrel has adjoining the shaft section, a raised shoulder portion having a cross sectional area intermediate between that of the working section and that of the shaft section of the mandrel.
Claim 4
Dependent Claim
24 words
The assembly of claim 1 wherein the dummy block is attached to a ram adapted to move to thereby cause extrusion of a tube.
Claim 5
Dependent Claim
20 words
The assembly of claim 1 wherein the dummy block socket is at least partially tapered outwardly from front to rear.
Claim 6
Dependent Claim
16 words
The assembly of claim 1 wherein the shaft is tapered inwardly away from the working section.
Claim 7
Dependent Claim
17 words
The assembly of claim 3 wherein the dummy block socket is tapered outwardly from front to rear.
Claim 8
Dependent Claim
19 words
The assembly of claim 1 wherein said mandrel is maintained within said socket by means of a fluid pressure.
Claim 9
Dependent Claim
12 words
The assembly of claim 1 wherein the dummy block socket is threadless.
Claim 10
Dependent Claim
104 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section and at least partially tapered outwardly from front to rear; and b. a mandrel placed in said socket which has a working section and a shaft section wherein the shaft cross sectional area is about equal to A2S/P1 + A2 where A2 is the average cRoss sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
Claim 11
Dependent Claim
104 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section and at least partially tapered outwardly from front to rear; and b. a mandrel placed in said socket which has a working section and a shaft section wherein the shaft cross sectional area is about equal to A2S/P1 + A2 where A2 is the average cRoss sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
Claim 12
Dependent Claim
42 words
The assembly of claim 9 wherein the working section of the mandrel has adjoining the shaft section, a raised shoulder portion having a cross sectional area intermediate between that of the working section and that of the shaft section of the mandrel.
Claim 13
Dependent Claim
27 words
The assembly of claim 9 wherein the dummy block socket is threadless and the mandrel is maintained within the threadless socket by means of a fluid pressure.
Claim 14
Dependent Claim
17 words
The assembly of claim 11 wherein the mandrel shaft is tapered inwardly away from the working section.
Claim 15
Dependent Claim
42 words
The assembly of claim 12 wherein the working section of the mandrel has adjoining the shaft section, a raised shoulder portion having a cross sectional area intermediate between that of the working section and that of the shaft section of the mandrel.
Claim 16
Dependent Claim
24 words
The assembly of claim 13 wherein the dummy block is attached to a ram adapted to move to thereby cause extrusion of a tube.
Claim 17
Dependent Claim
104 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section; and b. a mandrel placed in said socket which has a working section and a shaft section, said shaft section being tapered inwardly away from the working section and having a cross sectional area about equal to A2S/P1 + A2 where A2 is the average cross sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
Claim 18
Dependent Claim
104 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section; and b. a mandrel placed in said socket which has a working section and a shaft section, said shaft section being tapered inwardly away from the working section and having a cross sectional area about equal to A2S/P1 + A2 where A2 is the average cross sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
Claim 19
Dependent Claim
42 words
The assembly of claim 15 wherein the working section of the mandrel has adjoining the shaft section, a raised shoulder portion having a cross sectional area intermediate between that of the working section and that of the shaft section of the mandrel.
Claim 20
Dependent Claim
24 words
The assembly of claim 15 wherein the dummy block is attached to a ram adapted to move to thereby cause extrusion of a tube.
Claim 21
Dependent Claim
27 words
The assembly of claim 15 wherein the dummy block socket is threadless and the mandrel is maintained within the threadless socket by means of a fluid pressure.
Claim 22
Dependent Claim
20 words
The assembly of claim 15 wherein the dummy block socket is at least partially tapered outwardly from front to rear.
Claim 23
Dependent Claim
24 words
The assembly of claim 19 wherein the dummy block is attached to a ram adapted to move to thereby cause extrusion of a tube.
Claim 24
Dependent Claim
42 words
The assembly of claim 20 wherein the working section of the mandrel has adjoining the shaft section, a raised shoulder portion having a cross sectional area intermediate between that of the working section and that of the shaft section of the mandrel.
Claim 25
Dependent Claim
94 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section; and b. a mandrel placed in said socket which has a working section and a shaft section wherein the shaft cross sectional area is about equal to A2S/P1 + A2 where A2 is the average cross sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
Claim 26
Dependent Claim
94 words
In an extrusion machine, a dummy block-mandrel assembly which comprises: a. a dummy block having a socket concentric with the center of the dummy block cross section; and b. a mandrel placed in said socket which has a working section and a shaft section wherein the shaft cross sectional area is about equal to A2S/P1 + A2 where A2 is the average cross sectional area of the working section, P1 is the maximum fluostatic pressure in the container of the extrusion machine, and S is the frictional stress on the working section during extrusion.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |