Cruise control

There are various means of achieving linear displacement, with most of today’s major developments being in electro-mechanical actuators.

This method involves the conversion of rotary motion into equivalent linear displacement. Typically, a rotary driver, such as an electric or hydraulic motor, is mechanically connected to a long shaft — the screw.

The rotary motion of the electric motor will rotate the screw shaft which has a continuous helical thread machined on its circumference running along the length. These are called ball grooves because there are spherical balls that roll in this groove. The screw is inserted into another mechanical body, the ball-nut.

This also has similar helical thread machined on its inside diameter, plus a built in system to re-circulate the balls. These are trapped in the mating ball grooves on the screw shaft and ball-nut and convert the rotary motion of the screw shaft into linear displacement of the ball-nut.

When a major cruise ship line contacted Macron Dynamics about designing and installing a telescoping stage aboard two of its ships’ nightclubs, the company’s engineers were sure they could design a system to meet the specifications. There was, however, a catch — to eliminate downtime, the system had to be installed while the ships were at sea.