OF
A MACHINE
For Moulding Nails.
This Machine offers, I think, a valuable application of a well known Instrument: or rather of the principle on which it is founded. I allude to that parallel ruler which, by means of an additional joint, keeps it’s members not only parallel, but directly opposite each other. In my Machine for moulding Nails, I wanted to give motions to the two plates different, yet dependent on each other. Supposing then, ([Plate 24] [fig. 1, 2, 3, 4],) the upper plate a b, to be moved up and down by a lever, a screw-press, or any other first mover, I connect the under plate c d, with it by two (or four) strong parallel rulers e f, in such a manner, that when the plate a b is drawn upward it shall extend the arms of the ruler almost to a straight line, as represented in [fig. 4]; and then carry the under plate with it: and when it comes down again (see [fig. 3]) it shall not carry down the said under plate, until the same arms are bent into the position f g; that is, till the two plates touch each other: the use of which arrangement I will now explain.
The under side of the upper plate a b, is ground perfectly flat, and bored at proper distances with holes to receive and hold the punches which represent the shanks of the nails that are to be moulded. The lower plate c d is ground true both on it’s upper and under surfaces; the first to fit the under surface of the upper plate, and the under surface to impress a perfect plane on the sand below it. This under surface, shewn in an inverted position at [fig. 2], is moreover covered with proper prints 1, 2, 3, &c. to form the heads of the nails in question, and with proper gets (jets?) 3, 5, 6, &c. for conducting the metal to every part of the surface. I mean models in relief of those gets; and the under plate is further pierced with holes, placed exactly like those in the upper plate, bored indeed from that (and through the aforesaid prints of the nail-heads) after the parallel joints e f have been affixed. Now on another level plate with proper ledges, the sand boxes or flasks, [fig. 5 and 6], have been prepared; and have received an obtuse pyramidical form at one stroke from a competent press, the construction of which is easily conceived: or this might be done by hand, if preferred. These boxes, in-fine, are successively brought under the before described mechanism while in the state represented in [fig. 3], in which all the nail models are protruded through the under plate as at 1, 2, 3. The moulder now gives a stroke under the following circumstances:—Both the plates drop together and the nail models pierce the sand while the under plate makes it’s surface perfectly level: but when that motion is reversed, it is not the under plate which first rises, but the upper—by which the nail models are drawn out of their holes without disturbing the sand, for this is kept to it’s place by the under plate: and when, by the continued motion upward of the upper plate, the parallel joints are duly extended, and the nail models quite extracted; then, and not till then, the under plate leaves the compressed sand, in which are moulded as many scores of nails as the mould has been made for—and that, in a space of time almost imperceptible.
I shall conclude the subject by observing, that the counter flask or box for closing this mould is made in the same way, by a smooth plate prepared in the same manner; and which must fit the former, because they are both perfectly level surfaces.