Abstract: A self-lubricating gear-type spindle coupling for use with rotating equipment such as rolling mills, where lubrication is critical. The self-lubricating coupling includes reservoirs connected by first valve means to plenums formed by the retraction of the spring guides in the guide channels when the roll shaft is engaged at roll insertion. A partial vacuum is created in the plenums causing the first valve means to open and the plenums to fill with lubricant from a lubricant reservoir contained in the spindle shaft. When the roll shaft is removed and the compressive force is released from the spring assemblies, the guides move forward in the channels opening second valves which permit the lubricant to pass through the spring housings and onto the sleeves and hubs of the coupling to lubricate the gear teeth.

Abstract: A shear sleeve having a shearing zone of reduced cross-sectional area is fixed at the roll end portion of the shaft of a spindle coupling. The sleeve carries means coacting with a roll end sleeve for rotating it and the shaft. Mating surfaces of the shear sleeve and shaft are in contact during normal operation to prevent bending of the shear sleeve. When the shear sleeve shears under excessive torsional stress the surfaces separate and one end of the shear sleeve rotates freely on a bearing, or bearings, mounted on the shaft.