US792929A - Wheel. - Google Patents

Description

PATENTED JUNE 20, 1905. E. M. ROBERTSL WHEEL.

APPLIOATION FILED NOV.17,1904.

, W 8 Inventor Patented June 20, 1905.

PATENT OFFICE.

EDVARD M. ROBERTS, ()F ASHLAND, KENTUCKY.

WHEEL.

SPECIFICATION forming part of Letters Patent No. 792,929, dated June 20, 1905.

Application filed November 17,1904. Serial No. 233,213.

To all whom it may concern: v

Be it known that I, EDWARD M. Ronnnrs, a citizen of the United States, residing in Ashland, in the county of Boyd and State of Kentucky, have invented certain new and useful Improvements in Wheels, of which the following is a specification.

This invention relates to improvements in cast-iron wheels, such as are used on inclustrial railways, lumber, mill, and warehouse trucks, mine-cars, &c., where the wheel runs loose on the axle; and it has for an object to so form the hub of the wheel that the hub and wheel throughout will be stronger and hub will be more durable than the ordinary cast wheel and cheaper to manufacture.

Other objects and advantages will appear in the following description and will be more particularly pointed out in the claims.

In the drawings forming a part of this specification, Figure 1 is a front elevation of a wheel constructed in accordance with my invention. Fig. 2 is a vertical section of the said wheel mounted on an axle with interposed roller-bearings. Fig. 3 is a vertical section of the cast hub-bushing. Fig. 4 is a sectional view showing the hub-bushing secured centrally with'relation to the wheel rim or chill when same is used in making chilled treadwheels. Fig. 5 is a plan view of Fig. 4.

A central hub ring or bushing 1 is cast independently of the rest of the wheel. The central bore of bushes, cylinders, sleeves, and the like heretofore have been chilled on a tapering spindle, for the reason that it has been considered impossible to cast them around a chill having a uniform diameter, as, upon cooling, the bush, &c. would shrink and bind so tightly upon the chill or spindle that they could not be removed without breaking. I, however, overcome this difficulty in casting my bushing by placing around a steel spindle 2 of uniform diameter a coating of heat-resisting material, (about one-fiftieth of an inch in thickness,) which permits the spindle to be removed, leaving astraight hole 3 in the bushing; also, by using iron mixtures of proper chemical composition, preferably charcoal pig-iron five per cent. with No. 2 foundry containing two to two and one-half per cent.

silicon, so as to give the desired degree of chill or hardness to the bush, and having the molten iron very hot when poured into the mold and around the steel spindle or chill, the molds to be left until perfectly cool, when the spindle can be removed. leaving a straight smooth hole with a chilled or hardened surface. This obviates the necessity of boring or drilling the hub after casting, as the wheel is ready for the axle when it comes from the foundry, although where a refinement is required it can be ground with an emery-wheel to a glasslike surface. It can be made with anydegree of hardness, from that of a very close grained gray iron that can be worked with a tool to that of a chilled white iron that will resist any ordinary cutting-tool. Having the hardened smooth surface. it resists abrasion and reduces friction, giving long service for the hub, which outlasts the tread, whereas with ordinary cast wheels the hub wears out long before the tread ofchilled wheels. This hardened or chilled bush or hub is especially well adapted for wheels where roller-bearings are interposed.

After the bush is faced up on the ends by an emery-wheel and the sand cleaned off the outside surface it is placed in the sand mold made from the wheel-pattern and is located centrally with relation to the wheel-rim by a spider or gage 5 fitting within the central opening of the bush and having arms 5 resting at their ends on the rim-chill or on the mold representing the wheel-flange, depending on whether the wheel is cast ina rim-chill or not. The molten iron is then poured into the mold to form the rim 6, spokes 7, and outside hub 8 of the wheel, around the chilled bush 1, and integral therewith. By this manner of making cast-iron wheels the severe shrinkage strain, which occurs when wheels are cast in the ordinary way, is eliminated and partially relieved by annealing in pits, for the reason that it requires considerably less molten iron to complete the hub when the wheel is poured. Therefore the proportion of hot iron going to form the hub is in keeping with the iron contained in the spokes or web, and as the molten iron comes in contact with the cold bushing of a thickness of one-half inch or over it cools sooner than other portions of the wheel and has ceased to shrink before the spokes or web have lost their heat and capability to stretch without injury or danger of fracture, a wheel with straight spokes or a web without curve being made as free of shrink strains as a wheel with curved, spokes or dished web.

A further advantage of this construction of wheel is that for a corresponding weight of metal it has a much stronger hub, as it will be readily seen that a fracture in the bush or in the outside hub 8 will not continue through the second metal, as a board made up of two layers of wood secured to each other will not split as easily as a board in one piece.

I am aware that casting a hub around steel tubing is practicable and for certain purposes may be satisfactory; but for car or like wheels it would be unsuited. for the reason that the steel tube is annealed by the process of casting around it and is therefore unsuited for a wearing-surface requiring antifriction qualities.

In making wheels by casting around a previously-formed chill-castbushing there is an other advantage. In chill-casting the iron does not in all cases run smooth that is to say, if moisture gathers upon the chill from the moist sand, which occurs if the mold is left too long before pouring, or if the iron is not at sufliciently high temperature, or if there is not proper vent for the gases, defective hubs are produced, with holes, bubbles, or wavy parts within the bore or with rough unlillcd edges, which condemn the wheel. By chillcasting the bushing separately and previous to casting the wheel around such bushing it will be seen that any imperfections in the chill-casting of the bushing will be manifest before casting the wheel, and it thus becomes necessary only to condemn the compartively small bushings rather than waste the entire wheel. For similar reasons in chill-casting the rims of wheels if imperfections occur My invention makes possible the general use of roller-bearings 1n wheels where cheap equipment is required and where heretofore they have not been available, due to the great expense of putting in hardened steel or other hardened bushings into the wheels, for it is a well-established fact that roller-bearings must be hardened themselves and have a hardened surface to run upon to be practicable.

The construction of wheel herein shown is for purpose of illustration only, and I therefore desire it to be understood that I make various changes without departing from the spirit of my invention.

Having thus described my invention, what I claim as new is 1. A cast-metal wheel having integral rim, spoke and hub members; the hub comprising aseparately-cast chilled bushing around which the integral hub member of the wheel is cast and the thickness of the bushing and integral hub portion being approximately equal.

2. A cast-metal wheel having integral rim, spoke and hub members and a separatelyformed chilled cast bushing around which the wheel is cast.

3. A cast-metal wheel having integral rim, spoke and hub members and a separatelyformed chilled cast bushing of relatively large diameter with a thickness approximately equal to that of the cast portion of the hub and pro vidinga bore of sul'liciently large diameter to receive a roller-bearing.

The foregoing specification signed this 16th day of November, 1904.

EDWVARD M. ROBERTS.

In presence of Oscar. H nN'rnoRN n, W. C. RicnAunsoN.

Images