Split tube flexure
AssigneeVanderbilt University
InventorsMichael Goldfarb, John E. Speich
Life of this patent
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Abstract
This application describes the design of the split-tube flexure, a unique precision revolute joint that exhibits a considerably larger range of motion and significantly better multi-axis revolute joint characteristics than a conventional flexure. The development of this joint enables the implementation of spatially-loaded revolute joint-based precision machines with well-behaved kinematic and dynamic characteristics and without the backlash and stick-slip behavior that would otherwise prevent precision machine control.
Claims17
The split-tube flexure joint comprising
- a first tube having a wall, a first end, and a second end, a length of the tube being defined from the first end to the second end, the wall having a lengthwise slit defined therein along a longitudinal axis of the tube from the first end to the second end;
- first and second links tangentially attached to an exterior surface of the wall at respective first and second contact points along a contact line extending proximate the exterior surface of the wall and parallel to the longitudinal axis of the tube;
- and,
- each of the first and second links extending transversely to the slit;
- the first tube having an axis of rotation;
- a second tube having an axis of rotation, a first end, and a second end, the first end of the second tube facing the first end of the first tube such that the axis of rotation of each tube aligns;
- the first link being attached to each of the first and second tube nearer to their first ends than to their second ends;
- and
- the second link being attached to each of the first tube and second tubes nearer to their second ends than to their first ends.
A split-tube flexure comprising:
- a first thin-walled hollow shaft having a wall, a length, the wall having a lengthwise slit defined therein;
- a first link tangentially attached to the wall;
- a second link tangentially attached to the wall, the second link having a length, the second link length being transverse to slit;
- the first and second links contacting the wall at respective first and second contact points along a contact line extending proximate an exterior surface of the wall and parallel to the length of the shaft;
- the first shaft including first and second ends and an axis of rotation;
- a second thin-walled hollow shaft having a first end, a second end, a lengthwise slit defined therein and an axis of rotation, the first end facing the first end of the first shaft such that the axis of rotation of the first shaft is co-linear with the axis of rotation of the second shaft;
- the first link being attached to both the first and second shafts nearer to their first ends than to their second ends;
- and
- the second link being attached to both the first and second shafts nearer to their second ends than to their first ends.
A method of providing pivotal motion, the method comprising constructing a first flexure joint by
- providing a first thin-walled shaft having a lengthwise slit;
- attaching a first link to the thin-walled shaft, the first link extending transversely to the slit;
- attaching a second link to the first thin-walled shaft;
- extending the second link transversely to the slit;
- the first and second links tangentially contacting the shaft at respective first and second contact points along a contact line extending proximate an exterior surface of the shaft and parallel to the slit;
- applying a first force at the first link, the first force having a vector component perpendicular to the slit;
- and
- creating at the second link reactive forces reactive to the first force, and thereby achieving minimal force resistance along an axis of rotation and relatively large force resistance along other axis of the flexure joint.
Dependencies are inferred from the claim text.