A “goose-neck” G, shown in [Fig. 25], serves to temporarily contain the metal which is forced into the mold. An amount of metal slightly in excess of that required for one die-casting is placed in this goose-neck with a hand-ladle, previous to each operation of the machine. One end of the goose-neck is connected to the air pipe, E, while the other end terminates in the nozzle G1. This nozzle may best be seen by referring to the illustration of the machine shown in [Fig. 27], in connection with [Fig. 25]. One of the advantages in using this goose-neck is that the entire air pressure is expended upon the metal in the goose-neck, and, by reason of its isolated position, the goose-neck and its contents are kept slightly hotter than the contents of the melting pot.
The Die-operating Mechanism
The die-operating mechanism of the machine is contained within a hinged framework, shown in position for the removal of the die-casting in [Fig. 27]. Referring to [Fig. 26], in connection with the line illustration [Fig. 25], it will be seen that the die-holding mechanism is all supported upon the lower die-holding plate H, which is hinged to the edge of the base of the machine. A lock J serves to hold the dies and operating mechanism in the upright operating position, and by means of a counterbalance, suspended from an overhead rope which connects with the top of the mechanism at P, the changing of the position of this mechanism is easily effected, and when thrown into the horizontal position, as indicated in [Fig. 27], it rests upon a support while the dies are being opened and the castings ejected.
Fig. 27. Die-casting Machine in Position for Removal of Casting
The lower die is shown at H1 and the upper die K1 is mounted upon the upper die-holding plate K. Four rods L act as guiding members for the upper die-holding plate to slide upon. These rods L are mounted in fixed positions at the corners of the lower die-holding plate H, and at their upper ends the operating shaft supporting plate M is located in a fixed position, serving to support the upper ends of these rods. The position of this plate M is adjustable upon the rods by means of check-nuts, thus providing for the accommodation of thick as well as thin dies. A shaft O is supported in this top plate, and by means of the operating lever N working through slotted levers O1 and links O2, the upper die-holding plate and die can thus be removed from contact with the lower die at will.
The metal enters the die cavity through the nozzle G1 and after setting, it is necessary to cut the sprue formed by the surplus metal that remains outside the die cavity. For this purpose, a sprue-cutter, operated by means of hand-lever Q1, is employed. This sprue-cutting lever is hinged in the fulcrumed link Q2, and is held in its casting position by means of an adjustable stop on bracket Q3.
Fig. 28. General View of Trimming Department
In many dies, it is necessary that water be circulated through the die-blocks to keep them cool during the die-casting operation. In [Fig. 26], the water pipe may be seen at R, and hose pipes run from this supply to each side of the die-blocks, thus providing a cooling circulation. In this illustration, the pipes used for exhausting the air from the die cavity are apt to be confused with the cooling pipes, but by following the two pipes leading vertically down to the machine, the exhaust pipes may be seen and kept distinct from the water pipes.