US 5,690,567 A · Transmission for converting rotary motion into linear motion

Abstract

A transmission for reducing the pulley ratio between a drive shaft and a transmission shaft. The transmission is adapted to convert a higher speed rotary motion to a lower speed linear motion. The transmission has two pulleys rigidly mounted together on a shaft and the pulleys have a different number of teeth. A pair of belts are mounted on the drive shaft and a follower shaft, each one of the belts engages one of the transmission pulleys. One belt on the transmission shaft engages a pulley on the top of a first transmission pulley and another on the bottom of a second transmission pulley. When the drive shaft imparts motion to the belts, the belts move the transmission between the drive shaft and the follower shaft. By arresting the movement of one of the belts by a clutch/brake, the transmission can be converted into a two speed transmission. If the belts are independently driven, one each by two motors, the transmission becomes operable in an infinite number of pulley ratios. One particular application for this pulley transmission is in a carriage drive system for a Coordinate Measuring Machine.

Claims6

Dependent claims

A transmission for converting rotary motion of a rotary drive mechanism to linear motion of a carriage, comprising:

a belt assembly for connection to the rotary drive mechanism, including,
a drive shaft for coupling to the rotary drive mechanism,
a follower shaft spaced from said drive shaft, and
first and second belts mounted for rotation around said drive shaft and said follower shaft;
a first pulley driven by said first belt of said belt assembly at a first belt velocity and coupled to the carriage for rotation at a first angular velocity, said first pulley having a first pulley size;
a second pulley driven by said second belt of said belt assembly at a second belt velocity different from said first belt velocity and coupled to the carriage for rotation at a second angular velocity, said second pulley having a second pulley size;
and
a mechanical coupling between said first and second pulleys for establishing a predetermined ratio of said first angular velocity to said second angular velocity;
wherein the carriage, in response to rotary motion of the rotary drive mechanism, moves linearly with respect to said belt assembly at a carriage velocity determined by said first and second belt velocities, said first and second pulley sizes and the predetermined ratio of said first and second angular velocities, wherein the predetermined ratio of said first and second angular velocities is equal to one.

6 more elements

Dependencies are inferred from the claim text.

Transmission for converting rotary motion into linear motion

Life of this patent

Transmission for converting rotary motion into linear motion

Life of this patent

Abstract

Claims6