Rotary fluid cylinder for self-centering chuck

Claim 2

A rotary fluid motor comprising a cylinder, a piston movable in said cylinder and dividing the cylinder into two chambers, a conduit for supplying fluid into each chamber, and valve means connected to said conduits, said valve means being located within the cylinder and extending axially from one end of said cylinder to the other through aperture means in said piston whereby, when fluid is supplied under pressure through either one of the conduits, said valve means permit the flow of fluid through that conduit and the discharge of fluid through the other conduit; the valve means being further adapted, when the pressure in the conduit through which fluid is supplied drops below a predetermined value, to close that conduit.

Claim 3

The cylinder of claim 1 in which the valve means comprises, for each conduit, a closure member urged by biasing means towards a position in which it prevents flow through that conduit, the closure member being adapted to yield to allow flow through that conduit when the pressure of fluid in that conduit overcomes the biasing means; and further including means adapted to cause the closure member controlling that conduit to yield when the pressure in the other chamber rises by a predetermined value above that in the chamber into which that conduit leads.

Claim 4

The cylinder of claim 2, in which the conduits each include a conduit portion formed in a wall of the cylinder, and the valve means comprises two valve units each having an outer tube passing sealingly through the piston and extending from end to end of the cylinder, an innter tube being contained with radial clearance in the outer tube to define a space, the valve unit being transversely divided into a first and a second part by an annular ridge on one of the tubes extending into said space, the first part of the inner tube bEing in communication with the conduit portion formed in the cylinder wall, and having an aperture in its wall adjacent the ridge to communicate with the space between the tubes, the outer tube having an aperture in its wall at each of its ends to communicate with the chamber at that end, the closure member comprising an annular element located slidably in the second part of the valve unit in the space between the tubes and having radial clearance with respect to the tube on which the ridge is formed but being in sealing contact with the other tube, a spring biasing the closure member towards a position in which it bears sealingly against the ridge to prevent flow in the outer tube past the ridge; and further including a control element located slidably and sealingly between the tubes in the first part of the valve unit and having a projection extending towards the closure member, the projection being adapted, when the control element is moved toward the ridge, to engage the closure member and move it away from the ridge to permit fluid to flow in the outer tube past the ridge.

Claim 5

The cylinder of claim 2, including a tubular member solidly connected to the piston, the tubular member having at one end an internally frusto-conical appendix, a tension member being connected to the tubular member by means of a frusto-conical expansible collet that is internally threaded and is screwed on to a threaded portion of the tension member, the collet extending into the cavity of the appendix of the tubular member and being secured by a locking ring which bears on the collet and is screwed on to a threaded part of the external surface of the appendix of the tubular member.

Claim 6

The cylinder of claim 2, including a fixed cowl surrounding a part of the cylinder with a space between the cylinder and cowl, and including a plurality of fins formed on the cylinder and extending into such space, and passages communicating with such space to permit the circulation air under the fan effect of the fins.