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318 under conditions so far removed from those where cavitation occurs, that practically all of the vibration due to the propeller, is eliminated, as it has been long since recognized that the greater part of the vibration experi- enced in direct turbine driven vessels, THE MARINE REVIEW vided, thus preventing the pinion shaft from moving away or approaching the gear shaft, but permitting motion in the horizontal plane. The struts and float- ing frame are shown in detail in Fig. 5 and Fig. 6... Oil for lubricating the -- pinion bearings and pinion gear 1s sup- FIG. 6 is due to the fact that the propellers are worked in the region where cavita- tion is about to begin. The propeller vibration, which has been objectionable in a number of reciprocating engine vessels has been rightfully attributed to the change of angular velocity of the screw, and hence, since the turning moment and angular velocity are absolutely uni- form in a geared turbine, this source of vibration is eliminated. A vertical. and longitudinal cross- section and partial plan view of one of the 3,000-horsepower reduction gears for the Neptune, is shown in Fig. 4. Most of the readers are probably familiar with the general principle of the Westinghouse reduction -- gear, which consists of the floating or movable frame A, which carries the pinion in rigid bearings, the frame A having freedom, however, to adjust. it- self in the horizontal plane perpendicular to a plane passed through the center of the shaft and the nominal center of the pinion. In order to avoid having the weight of the pinion and pinion frame coming on the teeth of the gear and pinion, the frame A is supported on struts BB held in adjustable sockets DD, which permit the vertical distance between the center of the pinion shaft and the gear shaft to be accurately adjusted, and to prevent the radial component of the Pinion thrust lifting the frame from between its thrust abutments, a second set of adjustable struts CC and accom- "panying adjusting screws EE are pro- plied through the opening H, which communicates through a sliding contact I, Fig. 6, which communicates with the port J, extending the length of the pinion frame 4, Fig. 5. A spray of oil floods the pinion through the ports KK SeeaieSssessen se 33 34 ELEVATION ON CENTER UNE OF SHRP August, 1914 the bearing is carried around by the journal friction and the pressure of the oil film at the point where the load is carried must be sufficient so that the oil pressure times the bearing area is equal to the load on the bearing; otherwise the oil film would be destroyed and metallic contact would ensue as a result. By providing outlets at the point of maximum pressure, a bearing within the limits of its capacity, may be employed as a pump, -and this is what is done in the Westinghouse reduction gear, recess- es being provided in the bearings at the point of maximum oil pressure in the bearings, which communicate with pass- ages L, Fig. 6. A ball check valve is provided in each passage L, through the bearings, and each of the passages L communicates through this check valve with a common space N, which is connected by passage O to the space behind the pistons V. Now the total area of the pistons V is made approxi- mately twice the projected area of the bearings, and hence an oil pressure of approximately one-half that of the oil firm in the bearings if exerted on the pistons V, is sufficient to balance the thrust of the pinion; thus as the pinion revolves under any given thrust, oil from the bearings at the pressure of the oil film in the bearings is pumped HANOWHEELS at BIG. 7 and also supplies the bearings at the center line, or point of minimum pres- sure, As has been Previously pointed out, when a bearing rotates under load, un- less metallic contact occurs, oil supplied at the point of minimum pressure of through the passages L to the space N, and through the holes O to the pistons V, balancing the movable or floating frame A, carrying the pinion in the di- rection of the arrow, or opposite to the direction of the pinion thrust, until the opening in the passage E, in the arm SEO LO RA Oe