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Wrought-Iron Deck Turntable.
Engineering News—December 21, 1889

 

The accompanying cuts illustrate a type of wrought-iron deck turntable for locomotives, as manufactured by Cofrode & Saylor, of the Philadelphia Bridge Works, and patented in 188'7 and 1889 by Mr. F. H. SAYLOR, C. E., of the firm named.

In this turntable the main carrying girders are solid-web riveted girders with angle-iron lateral and diagonal bracing. The cross-girders are also made of plates and angles firmly riveted to the main girders, as shown in Figs. 1 and 2. The construction of the center pivot can best be understood by an inspection of the sections shown in Fig. 2. The upper casting of this pivot has a square projection on top planed so as to fit inside the box formed by the cross-girders, to which latter it is firmly bolted. The middle casting forms the top of the roller-box, and its top is planed to a flat cylindrical surface, having its axis at right angles to the table and accurately fitting the lower surface of the top casting. A wrought-iron key is inserted between these plates to prevent the two surfaces from sliding upon each other.

The special feature of the center pivot is found in this arrangement of the two upper castings. The tendency of the table to tip laterally is prevented by the horizontal cylindrical surface, which is about 20 ins. in width. The table can, however, tip slightly longitudinally, so that when the locomotive runs upon it the trailing wheels bear upon the circular track; but whenever the center of gravity is within 16 ins. of the middle of the table, a full bearing surface is furnished, and the tendency of the trailing wheels at both ends is to rise clear of the circular track, and to remain so while the table is being turned.

Steel plates, made to fit exactly the planed conical surfaces of the lower and middle castings constituting the roller box, provide bearings for the conical rollers.

Between these steel plates are chilled iron conical rollers, ground to exact size, each 6¼ ins. in length almost completely filling the roller box. In addition to these conical rollers there are two hardened steel bearing plates, the lower being doweled to the base casting and the upper provided with oil grooves to insure free turning. The roller box is oiled through a wrought-iron pipe extending through a plate iron cover on top of the cross frame.

The lower half of the roller box constitutes the base plate, and is 2 ft. 8 ins, square, with slightly rounded corners, and is provided with four bolt holes 2 ft. 2 ins. apart, center to center in each direction. These four holes are intended to receive four wedge bolts 1-and-an-eighth in. in diameter, let into the center bearing stone. The bolts should have 2-in. projection above the stone to the under side of the nut. The center bearing stone should not be less than 3 ft. square. All the parts of the center pivot are made to exact gauge, so that they can be duplicated at any time; they are the same size for all tables.

The vertical adjustment of the table is provided in a very simple manner; there are no screw bolts for adjusting the height at the center; this can be most readily accomplished by a wrought-iron plate between the pivot and the masonry, should it at any time be required. The adjustment at the ends of the table is provided by simply changing the number of thicknesses of the packing plates which are inserted between the journal boxes of the trailing wheels and the channel iron cross-girders which carry these, whereby the height of either of the trailing wheels above the circular track can be fixed as desired. All tables are provided with four packing plates, three-eighths-in. thick, for each journal box. Two cast-iron sockets for wooden levers, and two latches are furnished for each table.

This standard turntable is proportioned for turning an 86-ton consolidation locomotive, or an equivalent load. and they are turned out in lengths varying from 35 ft. to 75 ft. In a following issue we will show a half-through wrought iron turntable as made by the same firm.

A useful table of dimensions of pits, for turntables adapted to lengths varying between 35 ft. and 60 ft., is issued by the firm named, and is given herewith.


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