Positioning and damper device using shear force from cyclic differential compressive strain of a cross-linked thermoplastic

A positioning device comprising:

• a first element comprising a cross-linked thermoplastic;
• a non-circular second element configured radially adjacent a first side of the first element and configured for relative rotation with the first element about an axis, the non-circular second element comprising first and second protrusions;
• and
• a third element configured radially adjacent a second side of the first element;
• wherein the first element and the second element are configured to transition between relative stationary conditions and relative rotational conditions;
• wherein the first element is configured to slip relative to the second element during relative rotation of the first and second elements thereby producing a substantially repeatable shearing force;
• wherein the first element is subjected to substantially no compressive strain and is not compressed by either the second or third elements in the stationary condition;
• and
• wherein during the transition of the positioning device from stationary condition to rotational condition the first and second protrusions are configured to strain the first element thereby inducing compression strain on the first element of at least 3 percent.

A rotary damping device comprising:

• a first element comprising a cross-linked thermoplastic;
• a non-circular second element configured radially adjacent a first side of the first element, and configured for relative rotation with the first element about an axis;
• a third element configured radially adjacent a second side of the first element;
• wherein the first, second and third elements are configured such that essentially no compressive strain and no compression is induced on the first element by a feature of the second or third element while there is no relative rotation between the first and second elements and compressive strain of at least 3 percent is induced on the first element by the feature while there is relative rotation between the first element and the second element;
• and
• wherein the rotary damping device is configured such that torque increases as the relative speed at which first and second elements rotate also increases.

A positioning device comprising:

• a first element comprising a cross-linked thermoplastic;
• a second element configured radially adjacent a first side of the first element, and configured for relative rotation with the first element about an axis;
• a third element configured radially adjacent a second side of the first element;
• and
• wherein one of the first and second elements comprise a non-circular feature and the other of the first and second elements comprise a receiving feature configured to receive the non-circular feature such that the cross-linked thermoplastic avoids any compression by adjacent elements such that it is substantially unstrained when the non-circular feature is received in the receiving feature, and such that the first element slips relative to the second element such that the positioning device produces substantially consistent torque as the first and second element are rotated relative to each other even after positioning device is subjected to temperature changes;
• and
• wherein a compressive strain of at least six percent is induced on the first element when the non-circular feature is rotated out of the receiving feature.

A positioning device comprising:

• a non-circular shaft having a maximum radial dimension relative to its center axis about which it is configured to rotate;
• a cross-linked thermoplastic element configured radially adjacent the non-circular shaft;
• and
• a housing configured radially adjacent cross-linked thermoplastic element and configured with a minimum radial dimension relative to the center axis;
• wherein the non-circular shaft is configured to slip relative to the cross-linked thermoplastic element as the non-circular shaft and the cross-linked thermoplastic element are rotated relative to each other thereby producing a substantially repeatable shearing force;
• wherein the non-circular shaft, cross-linked thermoplastic element and housing are configured such that the cross-linked thermoplastic element is unstrained and not compressed by the non-circular shaft or housing while there is no relative rotation between the non-circular shaft and the cross-linked thermoplastic element and a compressive strain of at least 3 percent is induced on the cross-linked thermoplastic element by a feature on the shaft or housing while there is relative rotation between the non-circular shaft and the cross-linked thermoplastic element;
• and
• wherein the maximum radial dimension of the non-circular shaft from the center axis is less than the minimum radial dimension of the housing from the center axis.