Shearing-force mechanism with cross-linked thermoplastic

Abstract

A device includes first and second elements. The first element includes a cross-linked thermoplastic. The second element is configured to engage and to strain the first element by a predetermined amount. The first and second elements are configured to move relative to each other and such that movement of the first and second elements produces a substantially repeatable shearing force between the first and second elements.

1 . A device comprising:
 a first element comprising a cross-linked thermoplastic; and   a second element configured to engage and to strain the first element by a predetermined amount;   wherein the first and second elements are configured to move relative to each other and such that movement of the first and second elements produces a substantially repeatable shearing force between the first and second elements.   
     
     
         2 . The device of  claim 1 , wherein the cross-linked thermoplastic of the first element comprises a cross-linked polyethylene (PEX). 
     
     
         3 . The device of  claim 1 , wherein the cross-linked thermoplastic of the first element has a molecular weight less than 3,000,000. 
     
     
         4 . The device of  claim 1 , wherein the cross-linked thermoplastic of the first element has a melt flow index greater than zero. 
     
     
         5 . The device of  claim 1 , wherein the first element of cross-linked thermoplastic is injection-molded thermoplastic that is cross-linked after it is molded into a desired shape. 
     
     
         6 . The device of  claim 1 , wherein the first element of cross-linked thermoplastic is thermoplastic that is cross-linked as it is formed into a desired shape. 
     
     
         7 . The device of  claim 1 , wherein the deflection the first element by the second element causes at least a six percent strain on the first element. 
     
     
         8 . The device of  claim 1 , wherein the deflection the first element by the second element causes at least a ten percent strain on the first element. 
     
     
         9 . The device of  claim 1 , wherein the first and second elements are rotated relative to each other such that both the relative movement of the elements and the deflection of the first element by the second element produce a substantially repeatable torque between the elements. 
     
     
         10 . The device of  claim 1 , wherein the first and second elements are configured along an axial direction and are moved relative to each other in the axial direction such that both the relative movement of the elements and the deflection of the first element by the second element produce a substantially repeatable linear force between the elements. 
     
     
         11 . A shearing-force mechanism comprising:
 a first element comprising a cross-linked thermoplastic; and   a second element configured to deflect the first element thereby controllably straining the first element;   wherein the first and second elements are configured to move relative to each other and such that the combination of the controlled strain on the first element and the relative movement of the first and second elements produces a consistent shearing force between the first and second elements.   
     
     
         12 . The shearing-force mechanism of  claim 11 , wherein the cross-linked thermoplastic of the first element has a molecular weight less than 3,000,000 and has a melt flow index greater than zero. 
     
     
         13 . The shearing-force mechanism of  claim 11 , wherein the cross-linked thermoplastic of the first element comprises a cross-linked polyethylene (PEX). 
     
     
         14 . The shearing-force mechanism of  claim 11 , wherein the second element is configured to deflect the first element a predetermined and fixed amount such that the shearing force between the first and second elements is relatively constant. 
     
     
         15 . The shearing-force mechanism of  claim 11 , wherein the shearing force between the first and second elements is relatively repeatable for repeated relative movement of first and second elements. 
     
     
         16 . The shearing-force mechanism of  claim 11 , wherein an external load is applied to either of the first and second members thereby causing their relative movement and wherein the shearing force between the first and second elements is independent of the external load. 
     
     
         17 . The shearing-force mechanism of  claim 11 , wherein the second element deflects the first element, resulting in a normal force on the first element in a first direction, and wherein the relative movement of the first and second elements is orthogonal to the first direction on the normal force. 
     
     
         18 . The shearing-force mechanism of  claim 11  configured as a torque engine such that the first and second elements are rotated relative to each other generating a torque. 
     
     
         19 . The shearing-force mechanism of  claim 11  configured as a linear-force mechanism such that the first and second elements are moved relative to each other in an axial direction such that a substantially repeatable linear force is generated between the elements. 
     
     
         20 . A torque engine comprising:
 a first element comprising a cross-linked thermoplastic; and   a second element configured for relative rotation to the first element and configured to be engaged with the first element such that the second element deflects the first element in and such that the relative rotation and deflection of the first element produces a consistent torque for the torque engine.   
     
     
         21 . The torque engine of  claim 20  configured as hinge such that an external load applied to either of the first and second elements causing their relative movement and such that the torque between the first and second elements is independent of the external load. 
     
     
         22 . A linear-force mechanism comprising:
 a first element comprising a cross-linked thermoplastic; and   a second element configured for relative linear movement to the first element and configured to be engaged with the first element such that the second element deflects the first element in and such that the relative linear movement and deflection of the first element produces a consistent linear force for the linear-force mechanism.   
     
     
         23 . The linear-force mechanism of  claim 22  configured such that the first element is coupled to a seat and the second element is coupled to a corresponding head rest such that an external load applied to the head rest causes relative movement of the first and second elements and such that the linear force between the first and second elements is independent of the external load.