The Joly machine (Fig. 571) is composed of the same parts as the one already described (Fig. 101), but, by a change of position, the die is now horizontal. The cutting-table is replaced by a flat receiver balanced with counterpoises. This receiver is placed against the die, the machine is set in motion, the pipe issues from the die and presses against the receiver, which descends, since, being balanced, it only requires a slight force to move it. When the required length is reached, the machine is stopped, and the pipe is cut by means of a horizontal curved frame provided with a stretched wire. The pipe is removed, the receiving table is raised again, and the operation continues. With skill the workmen succeed in making the production almost continuous, for the clay is introduced between the cylinders without the machine being stopped, as is necessary in the piston machine (Fig. 572). In this machine a piston with double rack-work compresses the clay in a box the bottom of which forms the die. One of the sides of this box is movable, and is used for introducing the paste. This must be well compressed in order to avoid the presence of air, which would produce hollows in the walls of the pipes.
The Chambrette - Belon machine (Fig. 573) is used for making fitting pipes; for that purpose the die is provided, at the annular orifice through which the pipe passes, with a curved edge of the external shape of the socket. The receiving plate, which in this machine is above, is provided with a mandrel of exactly the same shape as the inner surface of the socket. If, then, this mandrel is placed against the die, the annular space left between the edge of the die and the mandrel will represent the socket. Hence the machine works as follows: The workman holds the plate against the die, the top of the clay issues, and meeting the mandrel spreads out so as to occupy the space between the edge of the die and the plate; the socket is thus made, and rests against the receiver, which is pushed up by the pressure of the clay issuing from the normal orifice of the die. The pipe is then cut with a stretched wire.
Fig. 573. Vertical Expression Machine, worked by Hand (Chambrette-Belon).
The loading of the machine with clay is effected by making the die turn upon a hinge.
The Whitehead machine (Fig. 574) is of the same type as the preceding one, except that the receiving plate is below instead of above the die.
Hand-worked machines are used in small factories and for making fitting pipes of small diameter,
Fig. 574. Vertical Expression Machine, worked by Hand (Whitehead).