ALQUIST GEARING FOR SHIP PROPULSION. 187 
3. As torque is gradually applied to the small Pinion A, the highest stress will come on 
the disks of Gears 4 nearest the driving end, from which I will suppose we are looking in 
Fig. 2, Plate 101. These disks will bend, the contact points moving, say, toward us. This 
will allow stress to come on to the next disk, notwithstanding the torsional yield of the pin- 
ion; and as the torque increases further all the laminations will become involved, the 
yields of the disks changing in direction when we pass from the right-hand to the left-hand 
spiral, or vice versa. It is quite obvious that if the tooth pressure is to be nearly equal 
on all the disks, the yield of each disk at the point of contact must be many times the maximum 
torsional yield at the pitch line of the pinion. This proportion will increase, also, in pro- 
portion to the cotangent of the hellical angle of the teeth, which angle is about 30 degrees 
in Fig. 9, Plate 108. Thus the deflection of the gear disks, to be effective, must be very sen- 
sible. It appears from what I have just said, that in Fig. 2 the flexure of the disks of 
Gears A is such that vertical lines remain vertical after deflection, the tooth contact points in 
the near disk, as just supposed, coming toward us. I have stated this at length to call up 
a clear picture of the action. Obviously, on account of this bending, the originally true 
spiral teeth on Gears A are no longer true spirals; where there is contact the angle of 
obliquity of the gear tooth is increased, the velocity ratio is no longer constant, and there 
will be hard bearing on the points of the pinion teeth and roots of the gear teeth—that is, 
we will have point contact. No doubt the teeth would grind away, relieving this hard con- 
tact; we would then have untrue teeth bearing hard over small areas, the positions of which 
would change with changing load; the teeth would, consequently, be brightened all over and 
have the appearance of perfect bearing. 
All this is increased in importance by the laminations or disks being few—five in each 
spiral of Gear A, and seven in each spiral of Gear B, Fig. 9. Thus the whole path of con- 
tact of one tooth may lie on one lamination, and the number of contact points on each Gear 
A will not be much, if any, greater than the number of disks. 
4. Pinions B are subject to cross-bending. If Pinion B in the foreground of Fig. 9 is 
bent upward in the center, the axis of Gear A, to which it is solidly attached, will fall toward 
the left. At the same time the axis of the distant Gear A will rise toward the left. I have 
shown, in the article referred to earlier, that this strain is far from negligible, especially 
where, as in this case, a pinion is supported in two bearings only. Gears A are thus thrown 
in opposite directions out of their proper plane of rotation, as the total tooth pressure of 
Pinion B is much greater than that of Gear A; and this, in spite of the forward bearing of 
Gear A, as bearings have clearance. To correct this the disks would have to be distorted 
about the horizontal axis, Fig. 2, through the centers of Gears 4. Against this strain they 
are enormously stiff, and the moments of the forces of tooth contacts A are nearly zero 
about this axis. 
Further consideration would show that the wheels cannot be so handed as to make the 
“Third” and “Fourth” actions compensate one another. 
Altogether, I prefer the line contact and easy adjustment of the floating frame gear to 
the small number of driving points and delicate adjustment of the Alquist gear. 
5. It would have been interesting if Mr. Emmet had discussed why “low peripheral 
speeds are more efficient than high speeds,” as stated in the second and last paragraph on 
page 183. High peripheral speeds will be accompanied by thicker oil films at the tooth con- 
tacts, which will go far to compensate for the greater rate of shear of the oil. But, grant- 
ing the statement (though I think it is not correct within speeds in use), the advantage 
