1. Field of the Invention
This invention relates to gear type couplings and, more particularly, to spindle couplings of the type used in connecting a powered prime mover to the rolls of a rolling mill as well as to like apparatus.
2. Description of the Prior Art
Generally, gear coupling of the spindle type such as those used in rolling mills include a coupling sleeve at each end of a spindle shaft. The sleeve at the driving end of the spindle shaft connects drivingly to a powered prime mover or a pinion stand and at the driver end of the shaft the sleeve connects to the spade end of a roll in the rolling mill. During operation excessive torsional stresses can be encountered that will lead to expensive and extensive damage to either the driving machinery or the rolling mill. These excessive torsional stresses can also lead to a catastrophic failure of the coupling itself, causing additional damage to both the driving machinery and the rolling mill as well as requiring a complete replacement of the coupling. U.S. Pat. No. 3,999,404 discloses one type spindle coupling which provides torque overload protection. While the disclosure of U.S. Pat. No. 3,999,404 does provide torque overload protection, the design requires that the shear element be mounted on the shaft and that mating and coacting surface of the shaft and shear sleeve be specially shaped to provide freedom of movement for the sections of the shear sleeve in the event of a torque overload.
Accordingly, the objects of the present invention include a more easily accessible shear element in that the hub of the shaft need not be disturbed in the event of a torque overload and a shear element that does not require special mating faces between the shaft and shear element.