7094. Tenney, P. L. March 21. Plug cocks.-To prevent rotary valves from binding, more particularly rotary valves of internal-combustion engines, the valve chamber is formed of two relatively eccentric intersecting bores B, D, the smaller bore D being within the periphery of the larger bore. Packing-rings 16, assembled in grooves 18, fit seats 15 of the larger bore, the valve 2 engaging the seat 17 of the smaller bore. Spring - pressed bearing shoes 20 hold the valve in contact with its seat. By this arrangement, the valve can expand without binding in its bearings. A coupling-ring 22 is inserted between the shaft 28 of the driving-gear and the valve 2, the ring having lugs 25, 23, Fig. 7, for respectively engaging notches in the disk 27 and valve 2. In multiple-cylinder engines, one continuous valve would be arranged, extending through the engine with the ports corresponding to the exhausts and intakes of the several cylinders. Escape of gas is prevented by the provision of oil cups 30.