US166799A - Improvement in casting pulleys - Google Patents

Description

2Sheets--Sheet I.

J. M U BDU GK.

Casting Pulleys.

Patented Aug. 17,1875.

Mi names. NI\\\Q\ N ETERS. PMOTOJJT R, WASHINGT 2 Sheets--Sheet 2.

.I. MUBDOBK.

Casting Pulleys.

N0.166,799, Patented Au g17,l875.

W names In'vcnior,

MPETERS. PHOTO-LIIHDGRAFHER. WASHINGTON. D G.

UNITED STATES PATENT OFFICE.

JOHN MURDOGK, OF CARVER, MASSACHUSETTS.

IMPROVEMENT IN CAS TING PULLEYS.

Specification forming part of Letters Patent No. 166,799, dated August 17, 1875; application filed April 17, 1874.

7 structing the pattern for molding such pulleys;

second, in the pulley so made as a new manufacture; and, third, in a mode of securing such pulleys to their shafts.

In making cast-iron pulleys in the usual way, in which a singleset of arms is used,

which are placed in the middle of the length of the pulley, and of suflicient strength to support the strain, and are attached to a hub at their inner ends, it is difficult to prevent the breaking of the arms or distorting the rim by reason of the unequal cooling and contraction of the parts, as is well understood by foundrymen, and to avoid this various expedients-are resorted to, such as making-the arms of such form as to allow them to yield to the strain without breaking in cooling, allowing the pulley to cool in the sand, so as to make the cooling more uniform, or uncovering the hub of the pulley as soon as the metal is set by removing the sand from the hub to hasten its cooling, while the rest of the casting remains buried, with other analogous practices to accomplish the same purpose; but by my mode of operation most of those expedients are unnecessary.

The distinguishing characteristics of my invention are, first, that the pulley is made with two sets of thin arms, each set being placed at or near each edge of the rim, and connected to the other at the center by a thin hub, so that the thickness of the metal in the pulley is nearly the same in all parts, and in all parts much thinner than would be safe in pulleys as usually made, which is accomplished by the use of two sets of arms placed at each end of the pulley, and making the hub connecting them thin, so that the rate of shrinkage in all parts is nearly uniform,-and the castings can entirely in green sand, and without the necessity of using any core-work; and, third, by the use of such a thin hub to the pulley some further provision is necessary to fasten the same to the shaft when it is desired to do this by set-screws, because the metalin the hub is not thick enough to form asuflicient nut for the screws, and for this purpose the hub is made of such shape as to form recesses upon the inside to receive bar-nuts, through which the set-screws work, and which nuts are made to bear against the inside of the hub close to the arms, so that the strain of the screws is received at the part of the hub which is strong enough to withstand it.

In the drawings, Figure lis a section through the middle of the pulley, showing the fastenings. Fig. 2 is a section at a right angle to Fig. 1. Fig. 3 is an inside elevation of onehalf of the pattern made'with a hub suitable for a loose pulley, where a chamber is made in the hub for a lining of soft metal for a wearing-surface. Fig. 4 is a section through the mold and pattern, showing the method of molding the same. Figs. 5 and 6 are two detached views of the bar-nuts and set-screws ,upon the back side in relation to the recesses that they bear against the interior of them out to the ends, as seen in Fig. 2, and nearly under the arm. The bosses B on the nuts, which secure the set-screws 0, pass through holes which are cast in the shell of the hub, as shown. D D are the arms, made of any desired form, but thin, and, by preference, of curved crosssection, as shown by the crosssection at d, Fig. 1, by which the armsare made much stronger laterally without a material increase in the weight. Bis the rim of the pulley, made of nearly uniform thickness throughout, with the draft upon the inside, made in the opposite direction from that usually made, as well as that of the hub The mode of constructing the pattern and of molding the same is shown in Fig. 4, in which F and G are the two parts of an iron flask, and H and H are the two parts of the pattern. I and 1 are the cope and nowel of the mold. J

is the middle part within the pattern, and J 2 the parts J and J are connected through the holes in the hub, and form one piece. The drafts of the pattern are made so'th'at the'two' parts draw away from the parting instead of toward it, as is usual.

In molding this pattern the method of pro cedure is as follows: One-half of the pattern is laid upon the molding-board, outside down, and rammed up inside, and stricken off, and then turned over upon a plain molding-board. The parting-surface at the face of the arms is finished, and parting-sand applied. Then one part of the flask is put over itand rammed up; then it is turned over, and the face isfinished outside of the pattern; then the other half of the pattern is put on, and the inside is rammed up uniting the sand with that in the other part of the pattern, and finished at the arms; then the parting-sand is applied to the whole surface; then the other part of the flask" is put on, and rammed up. To draw the pattern the cope is lifted off down to the middle parting, and one-half of the pattern is then drawn; then the cope is replaced, and the whole mold turned over; then the other part of the mold is lifted off, and the other part of those in common use.

joined tothe'rim" at or near its ed'ge's, an'd to each other by a thin hub, as a new manufacture. v

The recesses in the hub, in combination with th'e detachedvnuts' and set-screws, substantially as described.

Executed April 11, 1874.

V JOHN MURDOOK. Witnesses! WM. P. ED ARDS,

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