Posted to News on 29th Sep 2006, 20:46
Bi-directional ball screws move nuts in opposite directions
Placing two ball nuts on the same ball screw is often required to achieve a preloaded nut setup by exerting an axial force between the nut housings. When Abssac was confronted with a confectionery machine application, two nuts were still required on a single screw but, in this instance, both nuts would require opposite axial movement for a single screw rotation direction.
Rising to the challenge, Abssac delivered a ground 8mm diameter by 1mm lead ball screw in both a right hand and left hand format on the single screw. In effect, both screw thread forms met at the centre of the screw, separated by a small blank section. This enabled two nuts to then be mounted on the screw so as to move in opposition to each other for a given screw rotation direction. Therefore a pinching or extension movement could be achieved with the opposing nuts with up to 5micron repeatability accuracy.
From this application a further 4mm, 5mm and 6mm diameter screw series has been developed utilising 1mm to 5mm lead options. Matching the bi-directional requirement with high-end repeatable accuracy was another design solution supplied by Abssac.
