Patent US5008059A successfully refreshed from Google Patents.
US5008059A
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US
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Method for manufacturing a plastic part having a shape memory
Assignee: RXS Schrumpftechnik Garnituren GmbH
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Filing: 1989-10-23
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Granted: 1991-04-16
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Expires: 2009-10-23
Abstract
Abstract A method and apparatus forms a plastic part having a shape memory which has been formed to a second shape from an initial shape by the application of pressure to cause molecular orientations which are subsequently fixed by being cooled to a desired temperature and, when subjected to subsequent energy such as heating, will eliminate the molecular orientation and create a restoring force to return the part to the initial shape.
Inventors
- 👤 Helmut Kaeufer
- 👤 Christian Kipfelsberger
- 👤 Karl-Heinz Leyrer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:30
CPC Classifications
B; B29; B29C; B29C61/00; B29C61/06; B29C61/10; B29C61/0608; B29C65/00; B29C65/56; B29C65/58; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/12; B29C66/124; B29C66/1242; B29C66/12421; B29C66/40; B29C66/41; B29C66/43; B29C66/11; B29C66/114; B29C66/1142; B29C66/432; B29C66/4322; B29C66/50; B29C66/70; B29C66/73; B29C66/737; B29C66/7371; B29C66/73715; B29C66/739; B29C66/7392; B29C66/73921
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
200 words
A method for the manufacture of plastic parts of a thermal plastic synthetic material having a crystallite melting point and a softening point, said parts having a shape memory and being restored by the application of energy to an original shape from a second shape, the method comprising the steps of providing a preform of the original shape for the part in an apparatus having a cavity of the second shape of the part, said preform being free of cross-linked material, heating the preform to a first elevated temperature below the temperature of the crystallite melting point and softening point for the synthetic material, applying pressure to said heated preform in said cavity to change the original shape to said second shape and to introduce molecular orientations into the preform to change the preform into the part, maintaining the pressure on the part and cooling the part to a second elevated temperature below the first elevated temperature to fix the molecular orientations therein, removing the pressure after reaching the second elevated temperature, removing the part from said cavity and subsequently applying energy to cancel the molecular orientations and create restoring forces to return the part back to the original shape.
Claim 2
Independent Claim
200 words
A method for the manufacture of plastic parts of a thermal plastic synthetic material having a crystallite melting point and a softening point, said parts having a shape memory and being restored by the application of energy to an original shape from a second shape, the method comprising the steps of providing a preform of the original shape for the part in an apparatus having a cavity of the second shape of the part, said preform being free of cross-linked material, heating the preform to a first elevated temperature below the temperature of the crystallite melting point and softening point for the synthetic material, applying pressure to said heated preform in said cavity to change the original shape to said second shape and to introduce molecular orientations into the preform to change the preform into the part, maintaining the pressure on the part and cooling the part to a second elevated temperature below the first elevated temperature to fix the molecular orientations therein, removing the pressure after reaching the second elevated temperature, removing the part from said cavity and subsequently applying energy to cancel the molecular orientations and create restoring forces to return the part back to the original shape.
Claim 3
Dependent Claim
57 words
A method according to claim 1, wherein the step of providing comprises forming the preform in an apparatus by a method selected from injection molding, extruding, pressing and casting, and said step of applying pressure to said preform in said cavity is done while the preform is maintained in the same apparatus used for forming the preform.
Claim 4
Dependent Claim
33 words
A method according to claim 1, wherein the step of providing the preform includes introducing the preform into said cavity of the apparatus where the pressure is applied to cause the molecular orientation.
Claim 5
Dependent Claim
26 words
A method according to claim 1, which includes chemically cross-linking at least portions of the plastic part after it has been deformed into the second shape.
Claim 6
Dependent Claim
32 words
A method according to claim 1, wherein the step of applying pressure applies pressure with predetermined parameters and conditions so that the desired degree and direction of the restoring forces are obtained.
Claim 7
Dependent Claim
28 words
A method according to claim 1, wherein the degree and direction of the restoring forces are influenced by the nature of the pre-history of the preform being utilized.
Claim 8
Dependent Claim
33 words
A method according to claim 1, wherein the degree and nature of the restoring forces are influenced in the finished plastic part by the selection of the thermal plastic material for the part.
Claim 9
Dependent Claim
47 words
A method according to claim 1, wherein the degree and direction of the restoring forces are influenced in the plastic part by the modification of the fundamental building blocks of the macromolecules, by the molecular structure, and the interaction of the union of the molecule chains therein.
Claim 10
Dependent Claim
29 words
A method according to claim 1, wherein the degree and direction of the restoring forces are influenced in the plastic part by the geometry and dimension of the preform.
Claim 11
Dependent Claim
30 words
A method according to claim 1, wherein the preform has a plurality of sub-regions and wherein the step of applying pressure applies pressure only to selected sub-regions of the preform.
Claim 12
Dependent Claim
20 words
A method according to claim 1, wherein the step of applying energy to create the restoring forces applies thermal energy.
Claim 13
Dependent Claim
24 words
A method according to claim 1, wherein the step of applying energy to cancel the introduced molecular orientation causes restoring forces to be activated.
Claim 14
Dependent Claim
24 words
A method according to claim 1, wherein the creation of the restoring forces incurs by cancelling the stretching and distortion of the crystalline regions.
Claim 15
Dependent Claim
24 words
A method according to claim 1, wherein the restoring forces are activated by formation and growth of crystalline and amorphous phases of the material.
Claim 16
Dependent Claim
41 words
A method according to claim 1, wherein depending on the material being utilized for the preform, the step of applying the pressure applies a pressure with a surface load in a range of 10 N/cm 2 through 10,000 N/cm 2 .
Claim 17
Dependent Claim
25 words
A method according to claim 15, wherein the range of pressure is preferably in a range of 500 N/cm 2 through 5,000 N/cm 2 .
Claim 18
Dependent Claim
29 words
A method according to claim 1, wherein the step of maintaining the pressure holds the pressure for a predetermined time in a range between 0.5 seconds and 5 minutes.
Claim 19
Dependent Claim
19 words
A method according to claim 17, wherein the time is in a range between 2 seconds and 2 minutes.
Claim 20
Dependent Claim
36 words
A method according to claim 1, wherein the step of applying pressure includes utilizing pressure plates for applying the pressure, said pressure plates being maintained at a temperature range of between -50° C. through 160° C.
Claim 21
Dependent Claim
29 words
A method according to claim 1, wherein the step of applying the pressure applies the pressure at a reshaping rate of a range of 0.1 mm/sec to 100 mm/sec.
Claim 22
Dependent Claim
20 words
A method according to claim 20, wherein the reshaping rate is in a range of 1 mm/sec and 50 mm/sec.
Claim 23
Dependent Claim
30 words
A method according to claim 1, wherein the step of applying energy to cancel and to create restoring forces applies heat in a range of 50° C. through 250° C.
Claim 24
Dependent Claim
23 words
A method according to claim 22, wherein the step of applying heat applies heat in the range of 120° C. through 180° C.
Claim 25
Dependent Claim
17 words
A method according to claim 1, wherein the first elevated temperature is not more than 200° C.
Claim 26
Dependent Claim
22 words
A method according to claim 2, wherein the first elevated temperature is in a temperature range of 50° C. and 110° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-04-15 | 1994-10-15 | 1995-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-15 | 1998-10-15 | 1999-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-15 | 2002-10-15 | 2003-04-16 | $7700.00 | Window Closed / Lapsed |