US 5,405,222 A · Revolute motion machine tool

Abstract

This invention relates to a machine tool providing a unique approach towards positioning and movement for a workpiece and tool in numerical control machine tool applications. The goal is to provide decrease machine costs and maintenance. Current machine tools such as milling machines principally rely on linear sliding mechanisms to position a table and workpiece relative to a spindle and provide motion for cutting. In accordance with this invention motion and positioning is achieved through less cost and readily available mechanisms through use of a plurality of revolute joints. Arms are provided having tangential actuators featuring extremely high stiffness and zero backlash actuator capable of a high degree of positioning accuracy. The arms resemble three dimensional truss structures for added structural stiffness characteristics. Preferably a cable drum type tangential actuator is employed in conjunction with this invention. A number of revolute arms can be linked together each providing revolute motion about offset axes to provide number of degrees of revolute motion required for a given application.

Claims15

Dependent claims

A machine tool for providing coordinated positioning and movement between a tool and a workpiece, comprising:

a frame,
a first arm coupled to said frame by a first revolute joint providing rotation of a driven end of said first arm about a first axis,
a first tangential actuator for providing angular displacement of said first arm about said first axis,
a second arm coupled to either said frame or said first arm by a second revolute joint providing rotation of a driven end of said second arm about a second axis,
a second tangential actuator for providing angular displacement of said second arm about said second axis,
means for mounting said tool and said workpiece to said machine tool such that displacement of said driven ends about said first and second axes provide said coordinated positioning and movement between said tool and said workpiece, and
at least one of said tangential actuators having a cylindrical sector having a center of generation coincident with said first or second revolute joint and a capstan mounted adjacent said sector with wraps of a plurality of flexible cable segments having ends fixed to said sector and wrapped around said capstan.

4 more elements

Dependencies are inferred from the claim text.

Revolute motion machine tool

Life of this patent

Revolute motion machine tool

Life of this patent

Abstract

Claims15