Adjustable shims and washers
View Patent ↗A method comprising disposing an active device comprising a shape memory polymer upon a first surface; wherein the active device is operative to change at least one physical attribute in response to a thermal activation signal; activating the active device with a thermal activation signal to substantially decrease its modulus, contacting and compressing the active device with a second surface, and cooling the device to set a compressed geometry. In another embodiment, a method comprising disposing an active device comprising a shape memory polymer in a gap between two opposing surfaces; wherein the active device is operative to exhibit a memorized shape in response to a thermal activation signal; activating the active device with a thermal activation signal to increase a dimension of the active device; filling the gap between the opposing surfaces, and cooling the device to set a new gap filling dimension.
1. A method of re-dimensioning an active device, such as a shim, seal, spacer, washer, grommet, gasket or the like, comprising shape memory polymer, so as to maintain fixed relative spacing, alignment and/or positioning of assembled parts, said method comprising:
securing the device relative to a first surface defined by a first part, wherein the device is operative to change at least one physical attribute in response to a thermal activation signal;
activating the device with a thermal activation signal to substantially decrease its modulus;
fixedly securing a second surface defined by a second part relative to the first, and cooperatively compressing the device with the first and second surfaces, so as to form an assembly;
cooling the device to a temperature below the lowest glass transition temperature of the shape memory polymer, after forming the assembly;
causing the surfaces to relatively displace, so as to form a gap between at least a portion of said first and second surfaces and the device;
re-activating the device with a second signal when the surfaces are caused to relatively displace, so as to cause the device to reconfigure, and be recompressed by the surfaces, and the gap, to close; and
re-cooling the device to a temperature below the lowest glass transition temperature of the shape memory polymer, after re-activation.
2. The method of claim 1 , wherein the disposing comprises bonding the active device to the first surface with an adhesive.
3. The method of claim 1 , wherein the shape memory polymer is a thermoplastic polymer, a thermosetting polymer, or a blend of a thermoplastic polymer with a thermosetting polymer.
4. The method of claim 1 , wherein the shape memory polymer is a block copolymer, a graft copolymer, a random copolymer or a blend of a polymer with a copolymer.
5. The method of claim 1 , wherein the shape memory polymer comprises an electrically conductive filler.
6. The method of claim 1 , wherein the electrically conductive filler is carbon black, single wall carbon nanotubes, multiwall carbon nanotubes, metal particles, vapor grown carbon fibers, or a combination comprising at least one of the foregoing electrically conductive fillers.
7. The method of claim 1 , wherein the thermal activation signal comprises conduction, convection or radiation.
8. The method of claim 7 , wherein the radiation is infrared radiation, ultraviolet radiation, visible radiation, microwave radiation, or combinations thereof.
9. The method of claim 1 , wherein the thermal activation signal is an electrical signal.
10. A method of adjusting an active device comprising a shape memory polymer having a glass transition temperature, and securely disposed between two opposing surfaces defined by first and second interconnected parts, said method comprising:
heating the active device to a first temperature, so as to activate the device;
compressing the active device between the two opposing surfaces to a first dimension;
cooling the active device to a second temperature, wherein the glass transition temperature is between the first and second temperature, so as to set the first dimension;
causing the surfaces to relatively translate, so as to produce a gap between the device and at least one of the two opposing surfaces;
reheating the active device to the first temperature;
reconfiguring the active device and causing the first dimension to change to a second dimension, so as to fill the gap; and
cooling the active device to the second temperature to set the second dimension.
11. The method of claim 10 , wherein the active device is a seal, a spacer, a washer, a grommet, or a gasket.
12. The method of claim 10 , wherein the beating and/or reheating of the active device is accomplished through electrical heating.
13. The method of claim 10 , wherein the heating and/or reheating of the active device is accomplished by conduction, convection, and/or radiation.
14. A method of adjusting an active device disposed between two opposing surfaces comprising:
heating the active device comprising a shape memory polymer to a first temperature;
expanding the active device to fill a gap between the two opposing surfaces to a first dimension;
cooling the active device to a second temperature;
wherein the glass transition temperature of at least one polymeric component of the shape memory polymer is between the first temperature and the second temperature; and
reheating the active device to the first temperature at a later point in time;
repositioning the opposing surfaces; and
cooling the active device to the second temperature to set a second dimension.
15. The method of claim 14 , wherein the shape memory polymer is a thermosetting polymer, a thermoplastic polymer or a blend of a thermoplastic polymer with a thermosetting polymer.