Clamping and transfer device for elongate articles

Claim 1

A clamping and transfer device for transferring tube, rod or like articles in a direction longitudinally of the article, the device comprising a housing having a bore therein, a hollow piston slidably mounted in the bore for longitudinal movement therealong, fluid-supply passageways in the housing for supply of fluid to move the piston in both senses of longitudinal movement, and a radially contractible article-engaging tubular clamping member disposed within the follow piston with end portions of the clamping member fluid-tightly mounted in respect of end portions of the piston, the improvement consisting in a valve block mounted on the housing and having a bore through which is movable part of the piston and which provides an annular fluid-supply channel, a plurality of orifices in the piston providing communication from the fluid-supply channel to between the piston and the clamping member throughout movement of the piston in the valve block, and valve means on the valve block connected to the annular fluid-supply channel, whereby fluid can be supplied between the piston and the clamping member thereby to pressurise and radially to compress the clamping member onto an article when the piston is moving in one sense of direction, and whereby fluid can be returned from between the piston and the clamping member to release pressure on the clamping member while the piston is moving in the other sense of direction.