Engineers and Mechanics Encyclopedia 1839: Railways: William Howard

To render more useful the establishment of a railroad through a broken country, it has been a desideratum to construct a carriage which shall move with as much facility upon a serpentine, or curved, as on a straight road; and at the same time not to lose the peculiar advantages which the common method of fixing the wheels on the axis possesses. It is also desirable to lessen, if possible, the amount of friction, by means not too complex. These two ends, William Howard proposed to attain in the construction of carriages upon the following principles:-

"First, the connexion of the two beds of the axles at a point equidistant from each; and in the same manner the connexion between the hind bed of one waggon and the fore bed of that following it; or the fore bed of the leading waggon with any system of guide-wheels, so that the wheels not only of one waggon, but of a train, will follow one another in the same curve, without more lateral friction than when on a straight line.

“Second. The making of the axle revolve in its journals, and at the same time rendering either one or both wheels capable of revolving independent of the axles, as in a common carriage.

“Third, the application of a simple friction-wheel to diminish the friction of the axis upon its journal."

Mr. Howard next proceeds to explain these principles in detail. First,-

"If there be a track of a railroad of a circular form and we wish a carriage to move on it without lateral friction, the planes of the wheels must be parallel to the tangents of the two circles at the points where they rest on them, and each axle, consequently, in the direction of the radius of the circle. To find the point at which the axle must be connected to produce this effect, draw a perpendicular from the middle of each, and the intersection of these two perpendicular lines will be the point of junction required. The advantage of this over the common construction is that there the pivot of the beam connecting the axles is on the foremost axle, and consequently in turning, the hind wheels do not follow the tracks of the foremost ones, but describe a curve of smaller radius, causing great lateral friction on the rails.

“Second, The principle of making the wheels revolve with or without the axles in the present case, in to secure the advantages of the axle generally revolving with the wheels, and, at the same time, to permit one wheel to revolve faster than its fellow, when moving on a curved part of the road. The trifling relative improvement which this would produce between the axle and the wheel, would admit of these being adapted with considerable exactness.

“ Third, In the application of the friction-wheels, instead of an axle resting on the summit of a wheel, as is the usual method of application, and the only one known to the inventor, the wheel with its load is here made to rest upon the axle. According to these principles, the combination of which into a railway carriage forms the ground of a patent granted to Mr. Howard, the construction is to be as follows:-

"The size of the wheels, their distance apart, and the distance between the axles, are in the common proportions used in railway carriages. The connecting beam between the fore and hind axles is fastened firmly thereto by jaws or frames, to prevent lateral motion. This beam is divided in the centre, between the axles, one end having a tooth, and the other a socket, and cut of the epicycloid form, to keep the point of action at an equal distance from the centres of each axle. The axles are kept together by fastening the body by bolts to the beds resting upon each.

“Another method of construction is, to extend the beam from the hind axle, until the end of it rests upon the bed of the fore axle, while the beam from the fore axle reaches to a short distance only behind the central point of action. A bolt then passed through the centre of the hind frame, and the end of the fore frame, and equidistant from the axles, forms the pivot or point of action between them. In this case, the waggon is fastened firmly to the hind bed only, and to the extremity of the hind beam, which rests on the fore bed, which is made to traverse, laterally, more easily by a small roller upon a curved strip of iron. The friction-wheels are contained between upright stands or supports, of cast or wrought iron; each wheel leaving one on each side, connected at the top by a bolt and nuts, and having jaws at the bottom, wide enough to admit the axle in contact with the friction-wheel; each pair of friction-wheels is connected by iron bars passing through each arm of the jaws of the supports, and secured by nuts: between these bars the axle revolves, and the bars, rising above the axle, receive the beam, and form the fore and hind bends, to which the frames of the beam are securely nutted.

“To obviate the little friction which may arise from the centre of the friction- wheel being directly above the centre of the axle, it may be placed a little obliquely, and a small friction-roller used in one of the arms of the jaws, to destroy the additional friction there. The axles leave two shoulders at each end, one of which supports the waggon wheel, and is either firmly fixed to it, or only secured by a linchpin, and the other revolves client, the friction-wheel.

"These principles are not new, but the combination of them into a railway carriage is new, and entitles, the inventor believes, that his invention be secured by patent. The peculiar application of friction-wheels is also new, and claimed as original.

"Fig. 1 represents a perspective view of the whole carriage, with its friction-wheels attached.

“Fig. 2 represents the plan of the waggon, showing particularly the manner in which the beds of the two axles are connected. a is the iron waggon wheel, made as usual, except that it is arranged no as to turn on the axle, to which it is secured by the linch-pin b, or any other contrivance. c is a wheel fixed upon the axle, as in the common railroad carriage. d-d, the friction wheels moving upon the axles e-e, and supported by the supports f-f. The whole of these parts are of wrought or cast iron, and the frames are secured together by screws and nuts, so as to keep them solid, and as shown in the figure g, one of the bars connecting the two frames together, and secured in like manner. h and i are the two flames by which the two beds are connected by h bolt, at the point k, equidistant from the centre of each axletree; the flame i of the hind bed is prolonged, and rests on part of the frame h, immediately over the fore axle, the motion of its end, laterally, being facilitated by a small roller at 1.

"If it be found objectionable to place the body of the waggon entirely above the wheels, the two friction-wheels on one bed may be placed on a common axle. This arrangement will simplify the number of parts, and contribute to the steadiness of the motion."

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