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ing only when necessary to supply the deficiency of adhesion and their pressure against the flank of the teeth is only the balance of the leverage which is not sustained by the adhesion at the tread. They are not subject to the evils attending the use of fixed cogs which must almost necessarily be broken in their first contact with a rock laid at the foot, or top of an incline plane if they do not chance to enter into gear, and whose stubbornness subjects them to frequent accidents, an injury, besides the great friction which attends their action under all circumstances. The retreating cogs are endowed with the faculty of getting out of the way when not wanted, and of instantly being in-service without prompting, when they need is necessary. For planes much inclined the distance between the teeth should be such that the cogs shall over lay them about ⅟₁₆ of an inch. The cogs should be applied to each of the working wheels.
To enable locomotives to ascend inclined planes with heavy loads it is necessary also to give them an increased tractive power; I effect that object in the following manner, which is described as applicable to geared locomotive engines, but all locomotives may be geared for this purpose. There are the driving shaft taking its motion from the connecting rod and the following shaft communicating the motion to the main working wheels by cranks, and shackle-bars. On the driving shaft are caught wheels A, and C, Fig. 4, fixed to the shaft, on the following shaft are corresponding wheels B, and D, kept constantly in gear with A, and C. B, and D are loose on the shaft, and revolve freely around it except when they are alternately fixed, and held firmly by the spears E and F, on either side of B, and D, are the supports G, and H, fixed to the shaft, they are perforated for the blades of the spears to pass through and enter between the arms of the cog wheels. The gage bar I has two forks whose prongs lie in the grooves around the spears which are moved altogether laterally by means of a lever applied to the gage-bar, conveniently placed under the command of the engineer, the spears have the aid of a feather on the shaft, as well as of the supports G and H. By this means, the wheels B and D are alternately held fast to the shaft as occasion may require, when one is fast, the other revolves freely around the shaft without impediment to the one in service.
It is readily perceived that by increasing the diameter of the wheel D, and diminishing C, the tractive power of the engine may be increased four fold if desired in chinaging the running gear as described. A, and B, are the common moving gear combination in due proportion speed, and power for the level, and moderately undulating part of the road. On entering upon the ascent of an incline plane, or hill, as the momentum acquired on the level is spent, and the power of the engine begins to fail, the engineer, cutting off the steam for an instant, removes this spear E, and brings the other into gear by a single motion of the lever, without stopping the progress of locomotive. It is thus an able to move on up the plane with less speed than a level but with the redoubled power. When arrived at the summit the other wheels are brought into action again in like manner, and the locomotive proceeds with its accustomed speed. The tractive power of the engine may be just doubled, trebled, or quadrupled to adapted to the grading of the road on which it is to be used. Another mode of changing the gearing by holding fast the two wheels B, and D, alternately, is by means of levers placed in a groove lengthwise the shaft, one arm of which being raised operates like a feather entering a notch or groove in the bush of the wheel, the arms of the levers are raised, depressed by a slide, and gage bar as shown in Fig. 5.
Another mode is by moving the wheels B, and D, into, and out of gear alternately by a lateral motion on the shaft, effected by a gage bar with arms, shown in Fig. 6, as also another mode as at Fig. 7. I have also a method of drawing the retreating cogs within their sockets. But I do not consider this as necessary to their successful application, and use. It is however described here as there may be circumstances under which its adoption may be useful. It is thus: the rod attached to the cog is continued of a diminished size, not exceeding ⅟₁₆ of an inch, to within 1½ inches of the nave where it passes freely through the end of a lever which lifts against a nut on the end of the rod. This lever seen at h, in Figs. 2 and 3, passes in the direction of the axle inward, moves on a pivot in the projecting part of the nave at i, and the other arm inclines toward the axle and shown in Figs. 2 and 3. Encircling the axle at l, is a circular slide through holes in which the arms of the levers pass, and when moved on the axle from the nave it raises the arms of the axle, and thus draws the cogs within their sockets. This slide is moved by the gage bar M, having prong switch rest in the groove around the outer edge of the slide. This like the other gage bars, are moved end-wise in fixtures by means of a lever placed in any convenient manner to be within reach of the engineer. By this means whether the engine be at rest, or in motion, all the cogs are drawn into their sockets at once by a single motion of the engineer. There is one lever between each to spokes, each raising two cogs. The principal advantage of this is the withdrawing the cogs from action in
