A doffing/donning apparatus is used in combination with a row of winders each of which winds filamentary material upon a tube carried by a rotary spindle of the winder to form a package. The apparatus comprises a carrier mounted for movement generally parallel to and above the row of winders. A column is mounted on the carrier for horizontal movement. A package exchange arm is mounted on the column for up-and-down movement and is alignable with the winder spindle so that the package can be transferred to the package exchange arm. A tube exchange arm is mounted on the column for up-and-down movement and is alignable with the spindle so that a tube on the tube exchange arm can be transferred to the spindle. A shuttle is spaced horizontally from and vertically above the row of winders, and includes a package transfer arm and a tube transfer arm. The package exchange and tube exchange arms are moved along the column to the level of the shuttle. The column is moved horizontally toward the shuttle so that the package can be transferred from the package exchange arm to the package transfer arm and a tube can be transferred from the tube transfer arm to the tube exchange arm. The shuttle is transferred to a remote station where the package is removed from the package transfer arm and a tube is inserted on the tube transfer arm. The tube exchange arm comprises a rotary cylinder having inwardly projecting bristles. The cylinder is telescoped onto the tube while being rotated so that the bristles deflect tangentially to grip the tube.

A workpiece-holding plug has six sector-shaped segments that expand outwardly in a radial direction when in use and in contact with a lathe center. The segments have tapered outer wall portions which assume a precise cylindrical shape when the plug is expanded so that the central axis of the lathe center is maintained in precise concentric relationship to the central axis of the workpiece. The plug is of a particular construction which ensures that each of the segments shifts radially outwardly an equal distance, and yet has sufficient resiliency for self-contraction when the work operation is completed so that the plug may be readily removed from the workpiece. The plug has particular utility for holding a press roller on a lathe during reconditioning of the outer rubber surface of the roller.

A holder is shown for empty beverage cans which are to be tested for the abrasion resistance of coatings on the cans. In one embodiment, the holder is formed with an elastomer shell which is received in an empty can. An expander is inserted in a longitudinal opening in the shell and is rotated to engage cam surfaces on both the shell and holder thereby expanding the shell into contact with the empty can. The pressure exerted by the expanded shell simulates that of the contents of a beverage can. In a second embodiment the elastomer shell has a conical opening which receives a similarly conically shaped expander which expands the shell in all directions as it is forced longitudinally into the shell. A strap holds three cans and their holders together by engaging projections into shaped recesses in the tops of the expanders.

A rotary vane valve having a cylindrical housing with a pair of opposed end bells and an interior axial shaft. Opposed inlet and outlet openings on the side of the cylindrical housing allow transverse fluid flow through the housing and radial vanes project from the axial shaft to facilitate the transfer of fluid from the inlet at one pressure to the outlet at a different pressure. A pair of spaced shroud structures are fixed to the shaft at the ends of the vanes to generally separate the interior of the cylindrical housing from the end bells. These shroud structures are spaced from the cylindrical housing at their outer peripheral edges, but an annular throttle plate is spaced axially outwardly at a close distance from these shrouds and adjacent at its outer edge to the cylindrical housing to increase the velocity of purge gas flowing inwardly between the cylindrical housing and the outer peripheral edge of the shroud so that the escape of gas from the interior of the cylindrical housing is effectively prevented.

A rotary vane valve having a cylindrical housing with a pair of opposed end bells and an interior axial shaft. A pair of spaced shroud structures are fixed to the shaft at the ends of the vanes to generally separate the interior of the cylindrical housing from the end bells. These shroud structures are spaced from the cylindrical housing at their outer peripheral edges, but an annular throttle plate is spaced axially outwardly at a close distance from these shrouds and adjacent at its outer edge to the cylindrical housing to increase the velocity of purge gas flowing inwardly between the cylindrical housing and the outer peripheral edge of the shroud so that the escape of gas from the interior of the cylindrical housing is effectively prevented. The inner lateral surface of the annular throttle plate is divided into a low pressure zone adjacent the inlet opening and a high pressure zone adjacent the outlet opening in situations where the inlet opening is at a lower pressure than the outlet opening. The low pressure zone is roughened or has a plurality of radially spaced, concentric arcuate grooves while the high pressure zone is recessed with the result that frictional resistance to the flow of purge gas will be greater in the low pressure zone than in the high pressure zone so that the flow of purge gas will tend to be uniformly distributed at all points along the periphery of the throttle plate.