Patent ID: 7112018

Claim:
A device, comprising: a first rail having a longitudinal axis; a carriage moveably coupled to the first rail to translate in a direction along the longitudinal axis; a first axle mounted to the carriage and rotationally coupled to the first rail to rotate in proportion to a translational movement of the carriage in a direction along the longitudinal axis; a first encoder coupled to the carriage to create a first position signal based on a rotational position of the first axle; a first brake mechanism coupled to the carriage and to the first axle to selectively inhibit rotation of the first axle; and a controller linked to the first encoder and to the first brake mechanism to control the first brake mechanism in response to the first position signal; wherein the first rail is relatively stiff in bending about a first bending axis and relatively flexible in bending about a second bending axis orthogonal to the first bending axis, and the first rail is releasably attached to a workpiece such that the first bending axis is substantially normal to a workpiece surface and the second bending axis is substantially parallel to the workpiece surface.