The distance between the spiral blades being uniform, the lengths of the brick are absolutely uniform, and the drawing cut of the spiral blade cuts the end of the brick perfectly smooth, and almost mathematically square.
The speed of this spiral cutting-blade is controlled by the speed of the clay itself, hence, no matter how irregular the flow of clay from the die, the spiral runs in exact unison therewith, consequently the absolute uniformity in the length of the brick.
Fig. 63 shows the Chambers Machine as constructed up to and including the automatic sander.
Another device used by Chambers Brothers Company for severing the continuously moving clay bar into brick lengths is known as the " automatic wire cut-off," and is recommended by the manufacturers for smooth clays or those reasonably free from stones and gravel.
It consists of a regulating frame or table, on to which the clay bar is carried from the sander, and by which the cut-off is controlled or governed.
The belt carrying the clay bar runs around a measuring wheel, which determines the exact length the brick are to be cut.
The cut-off wires are strained on steel bows or springs to the proper tension to cut, and yield readily to obstructions.
The wires are carried by their springs on a sprocket-wheel over and through the clay bar, and are guided square by a cam, encased in an oil-tight case.
The partly-severed brick is supported and held against the unsevered bar until completely severed, when it is dropped on to the off-bearing belt and promptly carried off, allowing the wire to return above the bar again between the brick and the end of the unsevered bar. Thus the bar is divided into uniform lengths with square heads and with all the smoothness that a fine steel wire will give in the clay.
The wires either cut around the stones or spring over them, and run from morning until night without bother or trouble. Should a wire break, it can be removed at once without even stopping the machine.
Fig. 64 shows the Chambers machine as fitted with the auto matic wire cut-off. Machines with this style of cut-off are made of different capacities, ranging from ten thousand brick per day to one hundred thousand brick per day of ten hours.