Thermally Driven Piston Assembly And Position Control Therefor

Abstract

A thermally driven piston assembly comprises a material that undergoes a dimensional change when subjected to a temperature change in the temperature range of interest. The dimensional change imparts movement which effects an end result such as actuation, shock absorption, clutch action, braking, or mechanical power. The assembly can further comprise position sensing means for sensing movement of the component of interest, and passive and/or active heating and/or cooling means for effecting the temperature change.

1 . A thermally driven piston assembly, comprising: 
 at least one housing that remains rigid throughout a temperature range of interest;    at least one material that undergoes a dimensional change when subjected to a temperature change in said temperature range of interest;    said at least one housing cooperating with said material to effect movement of an element of interest; and    at least one thermal means for effecting said temperature change selected from the group consisting of heating means and cooling means.    
   
   
       2 . A thermally driven piston assembly as in  claim 1 , further comprising position sensing means for sensing a position of said element of interest.  
   
   
       3 . A thermally driven piston assembly as in  claim 2 , further comprising control means coupled to said position sensing means, wherein said control means controls said temperature change based on said position.  
   
   
       4 . A thermally driven piston assembly as in  claim 1 , wherein said material is a viscoelastic material.  
   
   
       5 . A thermally driven piston assembly as in  claim 1 , wherein said material is selected from the group consisting of foam and composite matrix.  
   
   
       6 . A thermally driven piston assembly as in  claim 1 , wherein said material is selected from the group consisting of elastomer, thermoset, and thermoplastic.  
   
   
       7 . A thermally driven piston assembly as in  claim 6  wherein said material is further selected from the group consisting of amorphous, semicrystalline, and liquid crystalline.  
   
   
       8 . A thermally driven piston assembly as in  claim 7  wherein said temperature range of interest is the glass transition region of said amorphous material.  
   
   
       9 . A thermally driven piston assembly as in  claim 7  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystalline transition region, and the melt transition region of said semicrystalline material.  
   
   
       10 . A thermally driven piston assembly as in  claim 7  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystallization transition region, the smectic C transition region, the smectic A transition region, the nematic transition region, and the discotic transition region of said liquid crystalline material.  
   
   
       11 . A thermally driven piston assembly as in  claim 1 , wherein said material has a molecular weight above that at which physical entanglement occurs.  
   
   
       12 . A thermally driven piston assembly as in  claim 1 , wherein said thermal means is selected from the group consisting of active and passive.  
   
   
       13 . A thermally driven piston assembly, comprising: 
 a housing comprising first and second housing portions having a hollow region therebetween that remains rigid throughout a temperature range of interest;    a material slidingly fitted in said hollow region such that said material is limited to movement along a single dimension of said hollow region, said material undergoing a dimensional change along the single dimension when subjected to a temperature change in said temperature range of interest;    wherein said dimensional change of said material effects movement of said second housing portion; and    at least one thermal means for effecting said temperature change selected from the group consisting of heating means and cooling means.    
   
   
       14 . A thermally driven piston assembly as in  claim 13 , further comprising position sensing means for sensing a position of said second housing portion along said single dimension.  
   
   
       15 . A thermally driven piston assembly as in  claim 14 , further comprising control means coupled to said position sensing means, wherein said control means controls said temperature change based on said position.  
   
   
       16 . A thermally driven piston assembly as in  claim 13 , wherein said material is a viscoelastic material.  
   
   
       17 . A thermally driven piston assembly as in  claim 13 , wherein said material is selected from the group consisting of foam and composite matrix.  
   
   
       18 . A thermally driven piston assembly as in  claim 13 , wherein said material is selected from the group consisting of elastomer, thermoset, and thermoplastic.  
   
   
       19 . A thermally driven piston assembly as in  claim 18  wherein said material is further selected from the group consisting of amorphous, semicrystalline, and liquid crystalline.  
   
   
       20 . A thermally driven piston assembly as in  claim 19  wherein said temperature range of interest is the glass transition region of said amorphous material.  
   
   
       21 . A thermally driven piston assembly as in  claim 19  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystalline transition region, and the melt transition region of said semicrystalline material.  
   
   
       22 . A thermally driven piston assembly as in  claim 19  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystallization transition region, the smectic C transition region, the smectic A transition region, the nematic transition region, and the discotic transition region of said liquid crystalline material.  
   
   
       23 . A thermally driven piston assembly as in  claim 13 , wherein said material has a molecular weight above that at which physical entanglement occurs.  
   
   
       24 . A thermally driven piston assembly as in  claim 13 , wherein said second housing portion comprises a hollow portion that remains rigid throughout said temperature range of interest.  
   
   
       25 . A thermally driven piston assembly as in  claim 24 , wherein said thermal means is a heating means positioned within said hollow portion of said second housing portion.  
   
   
       26 . A thermally driven piston assembly as in  claim 13 , wherein said thermal means is a cooling means positioned external to said first housing portion.  
   
   
       27 . A thermally driven piston assembly as in  claim 26 , wherein said cooling means is positioned circumferentially about at least a portion of said first housing portion.  
   
   
       28 . A thermally driven piston assembly as in  claim 24 , wherein said thermal means is a cooling means positioned within said hollow portion of said second housing portion.  
   
   
       29 . A thermally driven piston assembly as in  claim 25 , wherein said thermal means is a heating means positioned external to said first housing portion.  
   
   
       30 . A thermally driven piston assembly as in  claim 29 , wherein said heating means is positioned circumferentially about at least a portion of said first housing portion.  
   
   
       31 . A thermally driven piston assembly as in  claim 13 , wherein said thermal means is selected from the group consisting of active and passive.  
   
   
       32 . A thermally driven piston assembly as in  claim 13 , wherein said thermal means is a cooling means positioned external to said second housing portion.  
   
   
       33 . A thermally driven piston assembly as in  claim 32 , wherein said cooling means is positioned circumferentially about at least a portion of said second housing portion.  
   
   
       34 . A thermally driven piston assembly as in  claim 13 , wherein said thermal means is a heating means positioned external to said second housing portion.  
   
   
       35 . A thermally driven piston assembly as in  claim 34 , wherein said thermal means is a heating means positioned circumferentially about at least a portion of said second housing portion.  
   
   
       36 . A thermally driven piston assembly as in  claim 13 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters.  
   
   
       37 . A thermally driven piston assembly as in  claim 13 , wherein said thermal means is at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       38 . A thermally driven piston assembly as in  claim 13 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters and at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       39 . A thermally driven piston assembly, comprising: 
 a housing comprising first, second and third housing portions that remain rigid throughout a temperature range of interest, said first housing portion having a hollow portion therein;    a material slidingly fitted within said hollow portion such that said material is limited to movement along a single dimension of said hollow portion, said material undergoing a dimensional change along the single dimension when subjected to a temperature change in said temperature range of interest;    wherein said dimensional change of said material effects movement of said third housing portion; and    at least one thermal means for effecting said temperature change selected from the group consisting of heating means and cooling means.    
   
   
       40 . A thermally driven piston assembly as in  claim 39 , wherein said movement of said third housing portion effects a desired response in an element of interest.  
   
   
       41 . A thermally driven piston assembly as in  claim 39 , further comprising position sensing means for sensing a position of said third housing portion along a single dimension.  
   
   
       42 . A thermally driven piston assembly as in  claim 39 , further comprising control means coupled to said position sensing means, wherein said control means controls said temperature change based on said position.  
   
   
       43 . A thermally driven piston assembly as in  claim 39 , wherein said material is a viscoelastic material.  
   
   
       44 . A thermally driven piston assembly as in  claim 39 , wherein said material is selected from the group consisting of foam and composite matrix.  
   
   
       45 . A thermally driven piston assembly as in  claim 39 , wherein said material is selected from the group consisting of elastomer, thermoset, and thermoplastic.  
   
   
       46 . A thermally driven piston assembly as in  claim 45  wherein said material is further selected from the group consisting of amorphous, semicrystalline, and liquid crystalline.  
   
   
       47 . A thermally driven piston assembly as in  claim 46  wherein said temperature range of interest is the glass transition region of said amorphous material.  
   
   
       48 . A thermally driven piston assembly as in  claim 46  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystalline transition region, and the melt transition region of said semicrystalline material.  
   
   
       49 . A thermally driven piston assembly as in  claim 46  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystallization transition region, the smectic C transition region, the smectic A transition region, the nematic transition region, and the discotic transition region of said liquid crystalline material.  
   
   
       50 . A thermally driven piston assembly as in  claim 39 , wherein said material has a molecular weight above that at which physical entanglement occurs.  
   
   
       51 . A thermally driven piston assembly as in  claim 39 , wherein said thermal means is selected from the group consisting of active and passive.  
   
   
       52 . A thermally driven piston assembly as in  claim 39 , wherein said thermal means is a heating means positioned internal to said first and second housing portions.  
   
   
       53 . A thermally driven piston assembly as in  claim 39 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters.  
   
   
       54 . A thermally driven piston assembly as in  claim 39 , wherein said thermal means is at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       55 . A thermally driven piston assembly as in  claim 39 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters and at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       56 . A thermally driven piston assembly, comprising: 
 one or more pair of housings, each pair comprising first, second and third housing portions that remain rigid throughout a temperature range of interest, said first housing portion having a hollow portion therein;    a material slidingly fitted within said hollow portion such that said material is limited to movement along a single dimension of said hollow portion, said material undergoing a dimensional change along the single dimension when subjected to a temperature change in said temperature range of interest;    wherein said dimensional change of said material effects movement of said third housing portion; and    at least one thermal means for effecting said temperature change selected from the group consisting of heating means and cooling means.    
   
   
       57 . A thermally driven piston assembly as in  claim 56 , wherein said one or more pair of housings are located along an element of interest and wherein said movement of said third housing effects a desired response in said element of interest.  
   
   
       58 . A thermally driven piston assembly as in  claim 56 , further comprising position sensing means for sensing a position of said third housing portion along a single dimension.  
   
   
       59 . A thermally driven piston assembly as in  claim 56 , further comprising control means coupled to said position sensing means, wherein said control means controls said temperature change based on said position.  
   
   
       60 . A thermally driven piston assembly as in  claim 56 , wherein said material is a viscoelastic material.  
   
   
       61 . A thermally driven piston assembly as in  claim 56 , wherein said material is selected from the group consisting of foam and composite matrix.  
   
   
       62 . A thermally driven piston assembly as in  claim 56 , wherein said material is selected from the group consisting of elastomer, thermoset, and thermoplastic.  
   
   
       63 . A thermally driven piston assembly as in  claim 62  wherein said material is further selected from the group consisting of amorphous, semicrystalline, and liquid crystalline.  
   
   
       64 . A thermally driven piston assembly as in  claim 63  wherein said temperature range of interest is the glass transition region of said amorphous material.  
   
   
       65 . A thermally driven piston assembly as in  claim 63  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystalline transition region, and the melt transition region of said semicrystalline material.  
   
   
       66 . A thermally driven piston assembly as in  claim 63  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystallization transition region, the smectic C transition region, the smectic A transition region, the nematic transition region, and the discotic transition region of said liquid crystalline material.  
   
   
       67 . A thermally driven piston assembly as in  claim 56 , wherein said material has a molecular weight above that at which physical entanglement occurs.  
   
   
       68 . A thermally driven piston assembly as in  claim 56 , wherein said thermal means is selected from the group consisting of active and passive.  
   
   
       69 . A thermally driven piston assembly as in  claim 56 , wherein said thermal means is a heating means positioned internal to said first and second housing portions.  
   
   
       70 . A thermally driven piston assembly as in  claim 56 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters.  
   
   
       71 . A thermally driven piston assembly as in  claim 56 , wherein said thermal means is at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       72 . A thermally driven piston assembly as in  claim 56 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters and at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       73 . A thermally driven piston assembly, comprising: 
 a housing that remains rigid throughout a temperature range of interest, said housing having a hollow portion therein;    a material slidingly fitted within said hollow portion such that said material is limited to movement radially, said material undergoing a dimensional change radially when subjected to a temperature change in said temperature range of interest;    wherein said dimensional change of said material effects movement of said housing; and    at least one thermal means for effecting said temperature change selected from the group consisting of heating means and cooling means.    
   
   
       74 . A thermally driven piston assembly as in  claim 73 , wherein movement of said housing effects a desired response in an element of interest.  
   
   
       75 . A thermally driven piston assembly as in  claim 73 , further comprising position sensing means for sensing a position of said third housing portion along a single dimension.  
   
   
       76 . A thermally driven piston assembly as in  claim 73 , further comprising control means coupled to said position sensing means, wherein said control means controls said temperature change based on said position.  
   
   
       77 . A thermally driven piston assembly as in  claim 73 , wherein said material is a viscoelastic material.  
   
   
       78 . A thermally driven piston assembly as in  claim 73 , wherein said material is selected from the group consisting of foam and composite matrix.  
   
   
       79 . A thermally driven piston assembly as in  claim 73 , wherein said material is selected from the group consisting of elastomer, thermoset, and thermoplastic.  
   
   
       80 . A thermally driven piston assembly as in  claim 79  wherein said material is further selected from the group consisting of amorphous, semicrystalline, and liquid crystalline.  
   
   
       81 . A thermally driven piston assembly as in  claim 80  wherein said temperature range of interest is the glass transition region of said amorphous material.  
   
   
       82 . A thermally driven piston assembly as in  claim 80  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystalline transition region, and the melt transition region of said semicrystalline material.  
   
   
       83 . A thermally driven piston assembly as in  claim 80  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystallization transition region, the smectic C transition region, the smectic A transition region, the nematic transition region, and the discotic transition region of said liquid crystalline material.  
   
   
       84 . A thermally driven piston assembly as in  claim 73 , wherein said material has a molecular weight above that at which physical entanglement occurs.  
   
   
       85 . A thermally driven piston assembly as in  claim 73 , wherein said thermal means is selected from the group consisting of active and passive.  
   
   
       86 . A thermally driven piston assembly as in  claim 73 , wherein said thermal means is a heating means positioned internal to said housing.  
   
   
       87 . A thermally driven piston assembly as in  claim 73 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters.  
   
   
       88 . A thermally driven piston assembly as in  claim 73 , wherein said thermal means is at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       89 . A thermally driven piston assembly as in  claim 73 , wherein said thermal means is at least one heating means selected from the group consisting of wire heaters, fabric heaters, heating mantles, and flexible heaters and at least one cooling means selected from the group consisting of fluidic, electrical, and air.  
   
   
       90 . A thermally driven piston assembly, comprising: 
 first and second housings that remain rigid throughout a temperature range of interest, each said housing having a hollow portion therein;    a first material slidingly fitted within said first housing hollow portion and a second material slidingly fitted within said second housing hollow portion such that said first material and said second material are each limited to movement along a single dimension of said corresponding hollow portion, each said first and second material undergoing a dimensional change when subjected to a temperature change in said temperature range of interest;    at least one thermal means for effecting opposing dimensional change of said first material and said second material;    wherein said dimensional changes of said first material and said second material effect opposing movement of said first housing and said second housing; and    at least one thermal means for effecting opposing temperature changes in said first material and said second material.    
   
   
       91 . A thermally driven piston assembly as in  claim 90 , wherein said thermal means is a Peltier device.  
   
   
       92 . A thermally driven piston assembly as in  claim 90 , further comprising position sensing means for sensing a position of one or more of said housings.  
   
   
       93 . A thermally driven piston assembly as in  claim 90 , further comprising control means coupled to said position sensing means, wherein said control means controls said temperature change based on said position.  
   
   
       94 . A thermally driven piston assembly as in  claim 90 , wherein said material is a viscoelastic material.  
   
   
       95 . A thermally driven piston assembly as in  claim 90 , wherein said material is selected from the group consisting of foam and composite matrix.  
   
   
       96 . A thermally driven piston assembly as in  claim 90 , wherein said material is selected from the group consisting of elastomer, thermoset, and thermoplastic.  
   
   
       97 . A thermally driven piston assembly as in  claim 96  wherein said material is further selected from the group consisting of amorphous, semicrystalline, and liquid crystalline.  
   
   
       98 . A thermally driven piston assembly as in  claim 97  wherein said temperature range of interest is the glass transition region of said amorphous material.  
   
   
       99 . A thermally driven piston assembly as in  claim 97  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystalline transition region, and the melt transition region of said semicrystalline material.  
   
   
       100 . A thermally driven piston assembly as in  claim 97  wherein said temperature range of interest is selected from the group consisting of the glass transition region, the crystallization transition region, the smectic C transition region, the smectic A transition region, the nematic transition region, and the discotic transition region of said liquid crystalline material.  
   
   
       101 . A thermally driven piston assembly as in  claim 90 , wherein said material has a molecular weight above that at which physical entanglement occurs.