US1211249A - Method of making car-wheels. - Google Patents

Description

C. W. SHERMAN.

METHOD 0F MAKING CAR WHEELS.

APPLICATIQN FILED SEPT. B. 19.4.

Patented Jan. 2, 1917.

2 SHEETS-SHEET I.

Fi Ejl.

WITNE55E5.

ATTDRNEYS.

C. W. SHERMAN.

METHOD 0F MAKING CAR WHEELS.

' APPLICATION FILED SEPT. 8. |914. 1,21 1,249. E E Patented Jan. 2,1917.

2 SHEETS-SHEET 2.

Fi :21.4. V/ lib 1 LI-/Ii/ 7 f Ill E Ilml/ "lllllmll v 'nl f. f

CLIFTON W. SHERMAN, OF BUFFALO, NEW YORK.

METHOD OF MAKING GAR-WHEELS.

Specification of Letters Patent.

Patented Jan. 2, 1917.

Application led September 8, 1914. Serial No. 860,55'7.

T0 all whom it may concern: Y

Be it known that I, CLIFTON W. SHnR- MAN, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Methods of Making Car-l/Vheels, of which the following is a specification.

This invention relates to an improvement in the method of making integral cast metal car wheels. p

One object of this invention is the prof duction of such wheels at low cost and superior wearing qualities without. such defects as rough treads, seams, beads or cracks in the throat, the flange and the tread and particularly in the tread section adjacent to the flange; also to increase the integral formation or molecular affinity of the metal poured against the Chiller in the most vital part of a wheel at the bottom flange radius and tread section adjacent to the flange, thereby avoiding internal strains which develop such service defects, which are commonly known as shell outs7 or brake burns or throat and tread seams or cracks and which are frequently present in wheels made according to the methods heretofore known.

Another object of this invention is to so design the wheels as to cause a sequence of formation in pouring, shrinkage and contraction from a point where the effect of the chiller leaves off to the last part formed.

A further object is to form the chilled sec! cal section of the car wheel produced in the mold shown in Figs. l and 2. F ig( 4 is atop plan view thereof. Figs. 5 and 6` are fragmentary vertical'sections taken inv the correspondingly numbered lines in Fig. 3. Figs. 7 and 8 are fragmentary vertical sec.- tions of car wheels like those now commonly in use illustrating the defects in the same. Fig. 9 is a diagram illustrating the perfect pouring and feeding of castings which is practised` in irregular wheels by the use of Chillers on the` heavyvtread section in the design of wheel casting according to the present invention. v

' Similar characters of reference indicate corresponding parts throughout the several views.

Ordinarily the difference between the pattern size and the casting size of an article which is to be produced is commonly called shrinkage but in the further consideration of the present invention the reduction in the size of the cast article from that represented by the pattern will be divided into two separate and distinct parts or steps viz., shrinkage, which is the amount of reduction in space occupied by the metal as it passes from its fluid state into a hot solid state, and contraction, which is the amount of reduction in the size of the casting'as Vit passes from a hot solid condition to acold solid condition.l

AIn this invention advantage is taken of the fact that the best formation of the metal for producing a sound casting having the greatest amountv of molecular affinity is obvtained by pouring the metal in-such manner and with such rapidity and regularity that while contraction is 'taking place in the lowermost part of the casting, shrinkagev is taking yplace in the neXt following upper part of the casting and pouring of the metal is taking place for the next lfollowing upper part of the casting which steps progress upwardly in the order named from one section or part to another so that pouring, shrinkage and contraction always occur in unison until the casting is completed. In this manner it is possible for that section of metal in which shrinkage is taking place to furnish the necessary compensating metal required by the contraction in the section immediately' below the same and the metal which is being poured in one section to compensate for the shrinkage which is taking place in the section of metal neXt below that which is being poured, whereby va perfect and sound'casting is produced in which no defects are present due to contraction or shrinkage strains. This action of the metal is illustrated in Fig. 9 which shows -a mold cavity tapering downwardly from its upper open end to its lower closed end. In this figure the casting is represented as being divided into a plurality of superposed sections 1, 2, 3 and 4. The

lowermost section 1 of the vcasting is Vpoured first into this mold cavity followed successively by the remaining sections 2, 3, 4. As the lowermost section of metal l begins to shrink the molten metal in the second section 2 immediately follows up the shrinkage in the lowermost section which action occurs successively in like manner from the lowermost to the uppermost sections of metal in the mold cavity and a compensation for contraction also occurs progressively in like manner from the lowermost section of the casting to the uppermost one, so that no internal strains are produced in the casting but instead a perfectly solid casting is produced which has no defective formation and s therefore able t0 withstand the greatest oad.

e The uppermost section 4 of the mold cavity in Fig. 9 serves as the filling sprue and the metal lin the same serves as the head from which the metal is supplied to the next `lower section 3 to compensate Vfor shrinkage and contraction of the klatter whilek the samecools. This method of casting illustrated in Fig. 9 is utilized as far as practicable in themanufacture of the improved car wheel forming the subject of this invention so that the wheel in its completed form will bepractically free from the defects commonly due -to irregular form and unequal distribution of the metal which develop shrinkage strains and other defects previously referred to. The chiller in the present invention permits of using a heavy tread section and body plates, webs and brackets whichgradually ,increase in size from` the tread to the hub, thereby eliminating heavy T or Y-section in the body and keeping the pouring, shrinkage and contraction in Vproper sequence.

In Figs. 7 and 8 is illustrated the usual method of constructing a car wheel in whichY the body 5 of the wheel between the rim or tread 6 and hub 7 is connected with the inner side of the tread between its opposite edges so as to form a T-shaped section. Such` a wheel is usually made by filling up Y the dish and pouring the metal into the mold in the shortest time possible consistent with the construction of the mold. In considering the action of the metal in this mold from the time the filling of the cavity is be gun until the time that the casting is completed, the height of the same for convenience, as shown in Fig. 7, is divided into four sections 8, 9, l0, l1 which Vrepresents the tota'lrheight from the lower or rear endV of the hub to the upper edge'of thetread. This height is Vusually eight inches so that by dividing. the same into four equal sections a height of two inches for each section will be obtained. According to this division of the casting it will clearly appear'that that partjof the tread which takesthe greatest strain and wear is in the same Zone or section l() of the casting which contains the greatest amount of metal compared with other parts of the wheel. Approximately fifty per cent. of the weight of metal in the wheel is in the section l() and also requires about fifty per cent. of the total time for pouring the metal of the entire wheel, while that part of the wheel above the section l0 comprises about fifteen per cent. of the whole and that below the section 10 about thirty-five per cent. of the whole and requires a corresponding proportion of time for pouring the metal in those respective parts of the mold, this unequal formation of the several sections ofthe wheel being the principal cause which develops tread strains and defects in the same. lt will be observed that during the operation of pouring the metal into the section 9 of the cavity which is comparatively light in weight and which forms the flange l2 at the lower edge of the tread, this metal will pour and set very quickly on account of its small size and shape and by reason of the metal in this part d of the mold'engaging with the usual chill. This cooling effect of the metal forming the flange of the wheel is further hastened by the flowing of the metal over the surfaces of the drag of the mold and through those portions-of the mold cavity which form the brackets of the wheel, all of which combine to decrease thetemperature and shrinkage period of the metal in the flange part of the casting. It may therefore beV safely assumed that the metal forming the flange section of the wheel becomes set instantly and that contraction of this flange section has begun atV the same timethat the metal is being poured into the mold cavity for subsequently producing the upper sections l0 of the wheel tread. Owing, however, to the larger volume or area which is presented by the section 10v of the wheel which embraces thel junction or Y-section vplates of the body 5 and the tread 6 between the opposite edges of the latter, a slowing up of the formation of the vertical tread section against the chiller occurs as compared with the rate of filling up wnich takes place while the metal is being poured into the section 9 of the mold cavity forming the 'flange l2. lt follows fromV this slow pouring of the metal against the chill in section 10 that the usual defects are produced which are found in the tread sections of allV cast car wheels which are of the commonly accepted and used designs now generally foundon the market.

Figs..7' and 8 show the inherent defectsin the T-sections and throat and tread sections ofthe present design inasmuch as the tread defects blend into the invisible but are known to exist as inherent formation strains in all wheels of similar design due to the fast formation of the flange section 9 and the slower llt? formation of the tread section against the chiller as previously described. It is well known that all T-sections or Y-sections of castings not fed up by means of risers or cooled quickly by Chillers applied to the surface show defective formation at the junction and it is forthis reason that a T-section in the present invention is eliminted from the vital parts of the wheel castings.

All car Wheel makers are familiar with what is known as sweat in the throat which consists of small beads 13 of metal on the chilled surface of the wheel between the base of the flange 12 and the adjacent part of the tread, as shown in Fig. 7. This sweating in the throat sometimes increases to such an extent that it forms a wrinkle or seam 14 in the throat, as shown in Fig. 8. An examination of the fracture of such a wheel will generally show slight cavities in the tread from which the molten metal oozed after flange contraction has set in and an arc of the flange has shifted its position toward the hub while the tread section, with the possible exception of paper thickness against the chill, was still in a fluid condition. This is further evidenced by the fact that the distance from the apex of the flange to the face of the tread is always less than the inherent"v shrinkage in theV metal warrants. It is a well known fact that the center of a T-section or Y-section of any casting sets last and that its solidity varies according to the design of the pattern and other conditions so that defects are developed consisting either of a shrinkage hole, a spongy spot, or a lack of molecular affinity invisible to the naked eye but easily proven under test. Such a defect must therefore inevitably occur in the center of the T-section of the casting of a car wheel as indicated at 15 in Figs. 7 and 8 between the plate of the body and the tread of the wheel and between the members of the Y-shaped central part of the body, as shown at 16 in these figures.

It will be now apparent from the foregoing explanation that the formation of the essential or working part of prior car wheels, that is to say, the bottom flange radius section and adjacent tread section which have severe service contact with the rail and brake shoe and are subjected to severe expansion, contraction and compression strains, is of defective formation in the generally accepted designs. All the improved designs herein shown tend toward uniform time of pouring, shrinkage and contraction of the vital lower flange and tread section, thereby producing a rhythm of formation which increases the molecular aliinity of the metal in this important part of the wheel casting. All the most approved designs shown herein eliminate the body-plate or plate connections or intersections of T-form or Y-form except at juncture with tread, where proper lformation is assisted by the chiller, and at the hub which is large in area and last to be poured and properly fed from the head of metal in the mold cavity of the flask. All the approved designs shown also have the body, brackets and plate sections gradually increasing in volume from the tread to the hub to promote uniform shrinkage and contraction because under these conditions each succeeding part helps the perfect formation of the preceding part. f

The various forms of wheels embodying my invention which are shown in the drawings have therefore been so designed that the flange and tread sections can be poured quickly and in perfect unison which is impossible of accomplishment in the manufacture of car wheels as heretofore commonly designed.

Referring to Figs. 3, 4, 5 and 6 which show one of many forms of wheels which may be designed for practising my invention, represents the hub of the wheel, 17 the rim or tread and 18 the outwardly projecting annular flange which in this instance is arranged at the lower edge of the tread, although not necessarily so. The periphery of the rim or tread practically comprises a curved throat 84 arranged at the inner side of the base of the flange 18, a bearing face 81 arranged adjacent to the throat, and a tread extension 82 arranged between the bearing face and the adjacent edge of the rim or tread, as shown in Fig. 3. The load line 83 of the wheel is located at the central part of the rim or tread or about midway between its lower flanged edge and its upper unlianged edge, as shown in Fig. 3. These parts just described may be of any suitable and well known construction so as to come within certain standards adopted by the railways. Between the tread, section and the hub is arranged the body or sup' porting member which connects the same and which is so constructed as to give the wheels the l maximum strength with a minimum amount of metal for sustaining a certain load. This connecting body is cast integrally with the hub, tread and 'flange and, as shown in Figs. 3-6 comprises a central web 19 of substantially tubular form arranged concentrically between the hub and tread, an outer disk web 20 connecting the upper or unflanged edge of the tread or rim with the corresponding upper edge of the tubular web, an inner disk web 21 connecting the lower edge of the tubu-lar web with the corresponding end of the hub, outer brackets or arms l22 connecting the tread with the tubular web and also joining the adjacent part of the outer disk web, and inner bracketsl or arms 23 connecting the hub with the tubular web and also joining the inner disk web. The inner and outer brackets are preferably staggered relatively to each other and may be curved, as shown in Fig. 4 or of any other suitable arrangement or conformation to give the wheel the required strength and resilience, and the same may also be provided, if desired, with openings 24, 25 for the purpose of reducing the amount of metal in the same. These webs and brackets which constitute the elements of the body of the wheel between the tread and hub are of such dimensions that the metal poured into the cavity of the mold in which the wheelis cast will build up at a substantially uniform rate from the lower or inner edge of the tread and flange to the upper or outer edge of the same and also permit of effecting this pouring of the metal comparatively rapidly vso as to enable contraction, shrinkage and` pouring of the several sections of the wheel in a vertical direction to be eected with substantial uniformity from the lower part to the upper part of the wheel and thereby produce sound castings in which none of the defects heretofore referred to exist.

A mold for producing the wheel shown in Figs. 3-6, with the outer surface of Ithe tread and the flange thereof hardened, is shown in Figs. 1 and 2. As there shown this mold comprises a drag or lower flask section 26, forming the lower side of the mold cavity, a cope or upper flask section 27, forming the upper side of the-mold cavity, a metal chill, chiller or chill fring 2S arranged between the outer parts of the cope and drag and adapted to form that part of the mold cavity which produces the faces of Vthe tread or rim and the Aflange 112 of the wheel, a hub core 29 which forms the opening in the hub of the wheel, and inner and outer body cores 30, 31 which are supported between. the cope and drag in any suitable manner for form" ing the webs and perforated brackets Vor arms and the inner surfaces ofthe body. As the metal is poured through the sprue 32 in the central portion of the 'cope the same first fills the lower part of the mold cavity` which forms the lower end of the hub and the inner disk web, then flows laterally through the lower parts of the outer brackets and into engagement with the lower part of the chill for forming the flange of the wheel and adjacent parts, then the metal rises at a substantially uniform rate in the mold cavity during which the successive parts of the tread section are formed from the'lower edge toward the upper edge thereof until the mold is completely filled. The pouring of the metal against the Chiller is effected comparatively rapidly and its rise in the mold cavity is substantially uniform so that the shrinkage and contraction. of the'metall as it engages with the chill at ythe flange and tread forming partsthereof progresses from Vthe lower edge of the tread to the upper edge thereof with a uniform rhythm or sequenceV and without a greater area of metal being prese'nt in one part of the wheel than in another part lengthwise of the aXis of the wheel adjacent tothe flange and tread, thereby insuring substantial uniformity in the cooling of the metal throughout the entire mass without the formation' of any shrinkage strains or 'other defects in the same.

Itwill be 'noted that this car wheel has but a single plate or web in its body which connects the tread and hub and that comparatively heavy brackets areemployed in the body above and below that part of the tread having the throat and adjacent bearing face and flange, thereby securing rapid and regular formation of the wearing .parts of the wheell without internal strains or defects. In other words this disposition of the metal causes a minimum formation of the 'hub and body during the formation of that part of the tread having the flange, throat and adjacent bearing surface.

It will be 'noted that in the 'design for car wheel herein shown embodying my invent-'ion the metal is so distributed that the sectional area of the supporting member consisting ofthe plates or webs and `brackets, is smallest at the tread or rim and gradually increases toward the hub'; similar to the action illustrated in Fig. 9.

In my improved method of producing a cast 'metal car -wheel the speed of filling or vertical rise of the metal in the mold from the back ofthe -flange on-the rim toa point above the load line of the wheel is substantially uniform in. relation 'to the speed of pouring, and uniformvand fasteror at least as fast, but preferably faster, than the vertical formation of the corresponding sections or areas of the'mold cavityr below the flange and above the-rim. A car wheel produced in accordance with thisjmethod has its body or supporting member consisting ofthe plates, webs and brackets so arranged that upon pouring the metalof vthe same in the mold cavity it results in the production of a relatively uniform and fast formation of the rim` section from the lback kof the flange past the load line while the metal is being poured through the hub and bodyand at a uniform rate of speed, in other words, it results in a uniform or fast formation of one part of the rim las compared with another part of the same, so that the formation or filling of the flange and adjacent part of the rimer-tread is not delayed while the metal is being poureduniformly and the formation of the heavy parts of thebody is taking place at other times and under uniform pouring.' Y Itfollows from the foregoing that the vertical risero-f the metal in `the rim fromthe back ofthe flange to a point beyond or above the load line of the rim will be relatively faster than the average speed of vertical rise of metal in other parts of the wheel or in the wheel as a whole, that an increase is secured in the speed of forming the flange and adjacent part of the tread or rim section when poured at a uniform rate against the Chiller and that with a uniform rate of pouring the hub and inner parts of the plates and brackets are formed substantially before and after the flange and adjacent part of the rim section are formed, thereby decreasing the time of formation of the flange and adjacent part of the rim.

It will be apparent from the foregoing that in the construction shown and described it is possible to produce the entire flange and tread section of the wheel by pouring the metal quickly and causing the same to rise at a uniform rate in the mold and in perfect unison while forming the tread and flange sections thereof so. that the actions of contraction, shrinkage and pouring can follow each other in perfect rhythm or sequence and a perfectly sound wheel is produced which is not liable to break under the heaviest loads which are likely to be imposed upon the same in use.

I claim as my invention:

l. The herein described method of making car wheels having a hub, a flanged tread and a body connecting the hub and flanged tread, which comprises casting the flange of the tread and the adjacent bearing surface of the tread against a Chiller, and forming the flanged tread and that part of the body in line therewith comparatively rapidly and at a uniform rate of pouring of the metal into the mold cavity, as compared with those parts above and below the same the formation of the flange and load line portions of the tread being eected substantially while that part of the hub about midway between its upper and lower ends and the adjacent part of the body are being formed.

2. The herein described method of casting in a mold having a chill, car wheels having a hub, a rim provided with a tread and flange and a supporting member connecting said hub and rim7 comprising casting the rim against the chill at a faster rate than the other parts of the wheel duringa uniform rate of pouring of the metal into the mold the formation of the flange and load line portions of the tread being effected substantially while that part of the hub about midway between its upper and lower ends and the adjacent part of the body are being formed.

Witness my hand this 20th day of August,

CLIFTON W. SHERMAN. Witnesses:

THEO. L. Pori?, ANNA HEIGIS.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C.

Images