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US 2022/0090646 A1Published application
Passive variable stiffness device for vibration isolation
AssigneeOhio University
InventorKenneth K. WALSH
Life of this patent
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Abstract
Described and shown are passive variable stiffness devices, which are of compact design and configured to produce a restoring force that varies optimally with the isolator displacement when subjected to vibration-inducing loading.
Claims19
A passive variable stiffness device, comprising:
- a base plate;
- a pair of parallel variable diameter cylinders having first ends and second ends, each variable diameter cylinder mounted to the base plate so as to be restrained against linear movement and constrained to allow rotation only about its longitudinal axis;
- a linearly displaceable but rotationally restrained spring assembly comprising a pair of constant force springs located in a space between the variable diameter cylinders;
- a lead screw extending parallel to the longitudinal axes of the variable diameter cylinders, the lead screw coupled to the spring assembly such that rotation of the lead screw will produce a linear displacement of the spring assembly along the length of the lead screw;
- a lead screw gear train located near the first ends of the variable diameter cylinders and configured to rotate the lead screw upon rotation of the lead screw gear train;
- a lead screw gear rack residing above the lead screw gear train and in toothed engagement therewith;
- a cylinder gear train located near the second ends of the variable diameter cylinders and configured to rotate a first one of the variable diameter cylinders upon rotation of the cylinder gear train;
- a cylinder gear rack residing above the cylinder gear train and in toothed engagement therewith;
- a pulley attached to the first end of each variable diameter cylinder, and a belt coupling one pulley to the other;
- a top plate residing above the lead screw gear rack and the cylinder gear rack and connected to both, the top plate constrained to linear movement in a direction substantially perpendicular to the longitudinal axes of the variable diameter cylinders;
- and
- a cable coupled to a first one of the constant force springs and extending to and winding partially around a first one of the variable diameter cylinders in a helical fashion, and a cable coupled to a second one of the constant force springs and extending to and winding partially around a second one of the variable diameter cylinders in a helical fashion;
- wherein, linear movement of the top plate upon application of a sufficient force thereto will be resisted by a restoring force that varies optimally with the displacement of the top plate.
10 more elements
A passive variable stiffness device, comprising:
- a base plate;
- two cylinder pairs, each cylinder pair comprising a variable diameter cylinder having a helical groove encircling its circumference and a constant diameter cylinder having a variable lead helical groove encircling its circumference, the variable diameter cylinders and the constant diameter cylinders arranged in parallel and mounted to the base plate with the variable diameter cylinders located between the constant diameter cylinders, each of said cylinders restrained against linear movement and constrained to allow rotation only about its longitudinal axis;
- a top plate residing above the cylinder pairs and constrained to linear movement in a direction substantially perpendicular to the longitudinal axes of the cylinder pairs;
- a rack-and-pinion assembly connecting each variable diameter cylinder to the top plate;
- a constant force spring attached to a like end of each constant diameter cylinder;
- a cable coupled to a first one of the constant force springs, the cable wound around half of and in the helical groove of the constant diameter cylinder to which the spring is attached and also wound around half and in the helical groove of the variable diameter cylinder that is paired with the constant diameter cylinder to which the spring is attached, starting from opposite ends of the cylinders;
- a cable coupled to the second constant force spring, the cable wound around half of and in the helical groove of the constant diameter cylinder to which the second spring is attached and also wound around half of and in the helical groove of the variable diameter cylinder that is paired with the constant diameter cylinder to which the second spring is attached, starting from opposite ends of the cylinders;
- wherein, linear movement of the top plate upon application of a sufficient force thereto will be resisted by a restoring force that varies optimally with the displacement of the top plate.
5 more elements
Dependencies are inferred from the claim text.