MAKING CURVED EARTHENWARE PIPES OF EQUAL THICKNESS ON ALL SIDES.
The curves, elbows, and traps for sewer-pipe are now also made by machines especially constructed for the purpose, which are so arranged that by moving a plate placed over the mouth of the die the clay can be made to issue more rapidly from the opened side than from the other. The curve is formed in the pipe toward the side on which the space is contracted. By sliding the plate on the other side, the pipe will curve in an opposite direction, and by a succession of movements of the plates any desired form of curve or trap can be made.
The machine shown in Figs. 136 to 138 is the invention of Mr. Horace B. Camp, of Cuyahoga Falls, Ohio, and relates to the formation of curves, elbows, and traps.
Fig. 136 represents a central vertical section of a portion of an ordinary cylinder and attachments for making pipe and em bodying this invention.
To the cylinder A, from which the clay is pressed to form the pipe, by a piston (not shown), is bolted a cylinder head C, made converging to facilitate the descent of the clay. To the head C is bolted the outside hollow die D, having an inside diameter at the bottom of the size of the desired pipe, and within which, supported centrally by means of the rod F, is the core M, having an outside diameter of the size of the inside of the desired pipe. Between the die D and head C is a chamber or recess, in which is fitted a plate P, Fig. 136, free to slide longitudinally in one direction at right angles to the main cylinder and core, and moved by means of a hinged lever, as will appear from Fig. 138, which represents a transverse section of Fig. 136 at the bottom of the plate P, looking from below. Through the plate P is an orifice of the shape, and approxi mately of the size, of the pipe to be made, within which the mandrel is suspended, and having the edges beveled from the upper surface outward. When the plate P remains so that the
core M is exactly in the centre of the orifice therein, the clay descends with the same rapidity on all sides of the core, and is discharged in a continuous straight pipe. By sliding the plate to one side, the space S between the edge of the orifice in the plate P and the mandrel is lessened on one side, and corres pondingly increased on the other. The result of this is that the clay descends and escapes more rapidly on the opened side of the mandrel than on the side where the space S is contracted, and as it is discharged from the die D, it curves toward the side on which the space is contracted. By sliding the plate to the other side, the pipe will curve in an opposite direction, and by a succession of movements of the plate, any desired form of curve or trap can be made. The relative positions of the die D and core M remain at all times unchanged, and as a result the pipe is of equal thickness on all sides.
The principle of curving such pipes, by allowing the clay to discharge more freely on the one side of an annular orifice than on the other, is not new. Nor is the idea new of making parts of a pipe-machine movable at the will of the operator while the pipe is issuing, thereby enabling him to make reverse or other compound curves, as several devices have been in vented and patented for moving either the die D or core /V, while the pipe is forming. But all these devices have refer ence to a change in the annular opening between the core M and die D at the point of discharge, and herein they differ radically from this, in that the pipe is of uneven thickness on different sides.