A matrix plate swings on a hinge joint between the two presses. The hinge-pin is removable. Its ends can be seen projecting to right and left of the press columns. The hinge is at such a height that when the matrix plate is swung forward over the type box it will rest upon it in a nearly horizontal position. The pivoted box will adjust itself so as to come into parallelism with the plate.
Matrix Making, Moulding and Vulcanizing Apparatus.
When the matrix plate is swung back it falls upon the base plate of the vulcanizing press seen in the rear.
In use the composition used for the matrix is spread upon the matrix plate, which may for this purpose be removed from the apparatus. It is replaced and the hinge-pin is pushed home. This is done with the composition coated side facing the front of the apparatus as it stands in the cut. The plate is then swung forwards, the platen of the matrix press being turned forward out of the way, and is pressed down upon the type or other model that rests in the type box. If desired the press is used to force it home. The cross-bars of both the presses are arranged to swing each one on one of the pillars, so that the platens are turned to one side out of the way of the matrix plate as it is swung back and forth.
The pressure is released and the platens are turned aside. The matrix plate is swung over to the rear upon the bed-plate of the vulcanizing press. Here it lies with the composition-matrix upwards.
A lighted lamp, either alcohol or gas, is placed beneath the bed-plate of the vulcanizing press on which the matrix rests. This quickly dries it and brings it to a good curing temperature. The cross-bar and platen may be swung over it during the heating so as to be heated at the same time. The matrix is talced when dry and hot; the mixed sheet itself talced, is placed upon the matrix, the platen is screwed down upon it, and in a minute or two the moulding and curing is completed.
Rubber Stamp Vulcanizer.
A vulcanizer, properly speaking, is a vessel arranged to heat to a definite degree any desired articles which are to be cured. The favorite type have been the steam vulcanizers. If steam is generated from water at a constant pressure, other things being equal a constant temperature will be produced. By raising or lowering the pressure the temperature can be made to rise or fall. A steam vulcanizer is a tightly sealed vessel which contains water and which is provided with a thermometer or a pressure gauge as well as a safety-valve, safety disc or safety plug. By keeping the gauge at constant pressure or by keeping the thermometer constant the temperature can be limited and kept steady. The following table gives some pressure in pounds per square inch with temperatures corresponding to steam of such pressures: