US712533A - Core-baking apparatus. - Google Patents

Description

No. 7|2,533'. Patented Nov. 4, I902.

A. M. HEWLETT.

CORE BAKING APPARATUS.

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CORE BAKING APPARATUS.

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A. M. HEWLETT. com-i BAKING APPARATUS. (Applicatiofl filed Feb. 17 1902.

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A. M. HEWLETT. CORE BAKING APPARATUS.

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A. M'. HEWLE'I T.

CORE BAKING APPARATUS.

(Application filed, Feb. 17, 1902.) (No Model.)

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UNITED I STATES PATENT OFFICE.

. A LFREDM. HEWLETT, OF KEIVANEE, ILLINOIS.

CORE-BAKINGAPPARATUS.

SPECIFICATION forming part of -Letters Patent No. 712,533, dated November 4, 1902. Application filed February 17, 1902. Serial No. 94,440. N model-l To all whom it 772/001] concern:

Be it known that I, ALFRED M. HE LETT, a citizen'ofthe United States, residing at Kewanee, in the county of Henry and State of Illinois, have invented certain new and useful Improvements in Core-Baking Apparatus, of which the following is a specification, reference being had to the accompanying drawings.

Sand cores as usually employed in foundries are composed of sand mixed with some kind of a binder that will make the core very strong after it has beenbaked andcooled, and this binder must be of such a nature as to soften when the iron or brass comes in con The iron or brass when in a molten state must lie smoothly against the core, and if the hinder or core compound is not softened by the heated metal, but remains hard, the metal will blow or not lie up to it; yet the core must be very strong in order to stand the strain when the.

molten metal first strikes the core. Oi1,(principally linseed-0H,) rosin, molasses, and glucose are the principal bases for all hinders or core compoundspand in order to bake cores made by these compounds it is necessary to have a heat sufficient to practically fuse the rosin, glucose, or other core compound, and when oil is usedthe heat must be sufficient to actually bake itdry.

My present invention has to do with apparatus for baking cores, and, generally speaking, has for its object to provide an improved baking apparatus which operates continuously to conductthe cores into, through, and out of a baking-oven and to cool them before they are handled, so that they are not readily susceptible to injury.

In baking cores by a continuously-operating apparatus acting to conduct the cores continuously into and through a'baking-oven it is necessary to bake the cores quickly in order to avoid great length in the furnace,

and it is therefore necessary to secure a very high temperature in the furnace-as, forexample, from 400 to 700 Fahrenheitand even with this high temperature it is necessary to have the furnace from sixty to seventy feet long in order to bake cores of even moderate size in any great quantity. It is there fore impracticable to use indirect or radiated heat, such as that furnished by steam-coils, to heat the oven. In using steam it is economically impossible to maintain a temperature much, if any, higher than 250 Fahrenheit in the baking-chamber and have the two ends of the furnace constantly open to'a sufficient extent to allow the passage of the endless carrier, with the cores carried thereby, and with a temperature of even 250 it is impossible to economically and successfully bake cores in which binders composed of rosin,.glucose, molasses, oil, or similar substances are employed. It superheated steam should be employed, a temperature sufiiciently high might be obtained; butit would be economicallyinoperative,sincetheexpense of so maintaining the temperature would be enormous in addition to the expense of keeping up the pipes and coils through which the superheated steam would pass. It is therefore necessary from an economical and practical standpoint to provide direct means for heating the baking-oven, and this, broadly considered, is one of theprincipal features of my present invention.

In an oven arranged to operate in connection with a continuously-moving carrier by which the cores are carried into and through the oven it is necessary that the ends of the even be open constantly and that the opening be sufficiently large to permit of the free passage of the carrier, with its lead, of course. It is also necessary in order to satisfactorily bake the cores that the temperature of the baking chamber be substantially uniform throughout, and to secure such uniform temperature notwithstanding the constantlyopen end of the furnace is an important object of my invention, and the apparatus by which this is accomplished constitutes another feature of myinvention. Furthermore, it is also highly important in the baking of cores that the temperature be not only uniform throughout all .parts of the oven, but also that means he provided for insuring the subjection of the cores to the proper temperature for the proper length of time. In order to insure the proper baking of the cores regardless of the rising or falling of the temperature of the oven, it isnecessary that means be provided for increasing the length of time thatthe cores remain in the oven whenthe temperature of the oven falls and for decreasing the time during whichthe cores remain in the oven when the temperature of the oven 1l.-GS. To provide mechanism by-which this is automatically accomplished is another object of my invention, and I accomplish it, as hereinafter set forth, by automatically varying the speed of the carrierincreasing it when the temperature of the oven rises and decreasing it when the temperature of the oven falls. It is further desirable to automatically operate the drafts so that a substan tially constant temperature is maintained in the oven, and apparatus for this purpose also forms a feature of my invention.

In addition to the actual baking appliances my invention includes apparatus by which the work of preparing cores for the foundry is conducted with a minimum of loss from damage to the cores. Heretofore the baking of cores has been usually accomplished by the use of ovens of either one of two types. In one form of oven the green cores have been carried into the oven on trucks or boards and have been transferred by hand to shelves 0r racks in the oven and allowed to remain there until properly baked. With this form ofapparatus itis necessary to remove the baked cores from the oven while still hot, with a resulting large percentage of loss from damage to the cores, since the hot cores are soft and readily susceptible to damage in handling' In the second form of apparatus heretofore em ployed the cores have been placed on swinging shelves movable into and out of the oven, so that the cores could be introduced into the oven or withdrawn therefrom without the workmen going into the oven; but this apparatus also is objectionable for the reasons above given, since the handling of the cores, both in. their green state and when hot, is necessary. I

My invention provides means by which the necessity of handling the cores when in a condition in which they may readily be damaged is avoided, except as regards placing the green cores on the carrier. I employ a continuously-moving carrier which receives the green cores at one end and conducts them into, through, and out of the oven continuously and also for a sufficient distance heyond the oven to enable them to cool properly before they are removed. In this Way I avoid all liability of damage from handling after the cores have been baked, since when cool the cores are hard and may be handled with impunity. I further provide a continuously-moving carrier by which the cores are conducted fromthe tables at which they are formed to the baking-oven carrier, and are consequently delivered thereto in better condition and. with less loss from damage than would-be the case it they were carried by workmen from the forming-table to the baking-oven carrier.

A further object of my invention is to provide for properly baking cores of different sizes and shapes simultaneously in the same oven. As is well understood, the cores of diforent sizes and shapes frequently require to be baked for difierent lengths of time at a given temperature, and in order to bake such cores simultaneously I provide a plurality of endless carriers moving through the same furnace at different rates of speed, so that by properly distributing the cores upon the carriers a variety of sizes and shapes may be properly baked in the same oven at the same time.

In addition to the points above mentioned my invention also comprises certain details of construction, which will be'hereinafter set forth. p

The process which the apparatus herein described is designed to effect forms the subject-matter of an application for patent of even date herewith. I

In the accompanying drawings, Figure 1 is a side elevation of an oven, showing parts of the carrier and supporting devices therefor. Fig. 2 is a cross-section on line 2 2 of Fig. 7. Fig. 3 is a plan view of the receiving end of the apparatus, illustrating the carriers of the baking-oven and the apparatus by which the green cores are conducted thereto. Fig. tis a sectional detail of part of the controlling apparatus for regulating the speed of the carriers of the baking-oven. Fig. 5 is a side elevation of the carrying devices, the oven be-' 111g in section, showing the receiving end of the apparatus. Fig. 6 is a similar view showing the outlet end of the oven, the carrier, and the receiving-racks for the cores. Fig. '7 is a horizontal section of the oven, showing the grates. Fig. 8 is 'a plan view of the outlet end of the oven and illustrating also the carriers. Fig. 9 is a side elevation of the discharge end of the carriers, showing the driving mechanism therefor; and Fig. 10 is a plan view of the same, showing also the racks to which the finished cores are transferred and the position of the molding-machines with reference thereto.

11 indicates the oven, the construction of which is best shown in Figs. 1, 5, 6, and '7. As shown in Figs. 2, 5, and 6, the oven 11 is considerably longer than it is wide and is open at both ends near the top, the openings extending from side to side. The upper edge of the front wall 12 of'the oven forms the lower boundary of the opening at the inlet end of the oven, while the upper edge of the rear wall 13 forms the'lower boundary of the outlet-opening. The oven 11 is provided with a plurality of fire boxes or grates 14, the number depending on the length of the oven. As shown in Fig. 7, the grates 14 are distributed equallyat opposite sides of the oven and are placed at different distances from the ends thereof, the'idea being to'distribute the grates as nearly as possible throughout the area of the oven. Each of the grates 14 is inclosed by a wall 15, which forms three sides of a square and is open at the top, so that the site ends of the oven the heat from the grates heat may rise into the'upper portion of the oven, where the cores are carried. Each grate is provided with upper and lower doors 16 17, 1 respectively, forsupplying fuel and for re-. moving the ashes. The doors 17 also serve. as dampers to regulate the draft and to that end are hinged at their upper edges, as shown at 18 in Fig. 1. Provision is made for the. automatic adjustment of the dampers 17, as will be hereinafter described.

19 20 indicate smoke-stacks placed at oppo-f site ends and at oppositesides of the oven, as best shown in Figs. 1 and 7. V

21 22 indicate fines extending across the oven at the ends thereof, said fines commu nicating with the stacks 19 20, respectively, and openinginto the oven. By providing the stacks at the opposite sides and at the oppois conducted toward the ends of the oven, so that the ends even adjacent to the openings are substantially as hot as the intermediate portions of the oven. Furthermore, the location of the grates at opposite sides and at intervals throughout the oven efliectually distributes the heat and maintains a substantially uniform temperature throughout the entire oven. The temperature may be varied byopening or closing the drafts.

A B C indicate endless carriers, which, as shown in Fig. 2, are arranged side by side and are adapted to move through the oven, returning over the roof thereof, as bestshown in Figs. 5 andi6. As shown, each of the carriers is composed of two endless chains consisting of links 23, connected together at their ends, i the two chains of each carrier being connected by transverse rods 24, which also serve as a means of connecting the links of each .chain together. The ends of the rods 24 project beyond thelinks in which they are carried and carry rollers25, which are adapted to run on rails 26, provided for the purpose. The length of the rods 24 is such that the two chains composing each carrier are held at a comparatively short distance apart, forming narrow traveling conveyers, and the links 23 of eachcliain are of slightly greater width than the diameterof the rollers 25,-sothat the conveyers are adapted to receive metal plates ortrays, on which the cores are placed to be conducted through the oven.

As shown in Fig. 2, there are three pairs of rails extending through the oven, said rails also extending beyond the ends of the oven as faras the endless carriers go, as shown in Figs. 5 and 9., The rails 26 in the oven are mounted on suitable transverse supportingbars 27, as shown in Fig, 2, and outside the even they are supported by similar transverse bars28, secured in supporting-frames 29, provided at suitable intervals, as. shown in Figs. 5 and 9. The rails 26 are fixedlysecured at one end to their supports, but that. portion of the railswhich extends through the oven to the receiving end of the apparatus rests loosely on the transverse bars 27 and 2S,

so that the rails are free to move longitudinally when expanding or. contracting by reason of variationsin, the. temperature of the oven.

Suitable means may be provided forpreventing them from being displaced laterally. In Fig. 6 I have shown the rails as beingfixedly secured to a supportBO, provided at the out- .let end of the oven, said support being provided with a brace 31 to resist the end thrust occasioned by the expansion and contraction of the rails.

32 33 34 indicate sprocket-wheels mounted at different distances from the inlet end of .the oven in the supportingframes 29, as shown in Fig. 5. The sprocket-wheels 3233 .34 are in line, respectively, with the-carriers opposite ends of the carriers AB 0, respec-.

tively, as shown in Fig. 10. The-latter sprocket-wheels are, however, notadjustable longitudinally.

42 indicates an engine or othersuitable source of power, which in the construction illustrated operates through a belt 43 and pulley 44 to drive a shaft 45. Said shaft carries a pinion 46, which meshes with a gear 47, mounted on a shaft 48, the latterashaft carrying apinion 49, which meshes with a gear 50, 1 Said shaft 51 carries carried by a shaft 51. a pulley 52, which is connected byia belt 53 with a pulley 54, mounted onthe shaft .55 of the sprocket-wheel 39. Said shaft also carries a sprocket-wheel 60, which is connected by a link belt 61 with a sprocket-wheel 62,

mounted on the shaft 63 of sprocket-wheel 41, which drives carrier G. Theshaft 63 also carries a sprocket-wheel 64, which is connected by a link. belt 65 with a sprocket-wheel 66, mounted onthe shaft 67 of sprocketwheel 40, which drives carrierB. By thiscon- .struction the three carriers A B C are driven from the engine 42, but at diiferent rates of speed, since by making the sprocket-wheel 6,0 of less diameter, the sprocket-wheel66 be-' ing next larger and thesprocket-wheel 62 the largest, the carrier A noves at the highest rate ofspeed, the carrier B at a slower rate, and the carrier 0 at the slowest rate. object of this construction is to provide for subjecting diiferent kinds and. sizes. of 1 cores to the drying temperature for ditferent periods of time, as certain classes of cores require drying for algreater length of time than others. 1

While the driving apparatus described The tion access is readily had to each of the conveyers. Furthermore, the shortest conveyer travels the shortest distance outside the oven, thereby compensating for its reduced speed. Thisis quite an advantage, especially in loading the carrier 0, since the articles are placed upon it nearest the inlet-opening, and conse{ quently are carried into the oven much sooner than they would be otherwise. Of course the articles carried by the conveyer 0 remain in the oven a considerably longer time than those carried by either of the other conveyers.

' The driving apparatus is arranged so that the lower portions of the conveyers move through the oven, entering at the inlet end shown in Fig. 5 and passing out at the end shown in Fig. 6. The upper portions of the different conveyers are supported upon rails 68, which extend over the oven 11 and from end to end of the apparatus, being supported upon transverse bars 69, placed at suitable points, as best shown in Figs. 1, 5, 6, and 9.

As shown in Figs. 6 and 9, the conveyers extend a considerable distance beyond the outlet end of the oven. arrangement is to provide for cooling the cores after they have been baked before they are removed from the conveyers. After the cores have been baked and while they are still hot they are quite tender, andif removed from the carrier or otherwise handled before:

they have been cooled sufficiently to set there is great danger of breakage. the carriers, however, a considerable distance beyond the oven the cores are carried slowly In the arrangement shown core-racks 71 are provided between the con veyers and'the foundry, as shown in Figs. 9 and 10. are adapted to receive the cores when taken from the carriers. The cores are then taken from the other side of the racks and carried by hand to the molding-machines or to the part of the foundry where they are to be used.

The object of this By extending and consequently are not overbaked.

Said racks I The speed of the conveyers is regulated by the heat of the oven, and to this end'the expansion and contraction of the rails 26 is utilized to control the speed of the engine 42. I prefer to use only one of the rails for this purpose. As already described, the rails 26 are secured to the support 30 near the outlet end of the oven 11, as shown in Fig. 6. Consequently the expansion or contraction of the rails due to the heat of the oven causes the ends of the rails at the receiving end of the apparatus to move longitudinally to a greater or less extent, depending on the variations in temperature. To utilize this movement, a lever 72 is provided, pivoted at its lower end to a suitable support 73, arranged near the inlet end of the oven, as shown in Fig. 5. To the upper end of the lever 72 is connected a connecting-rod 74, (best shown in Figs. 5, 8, and 10,) which is connected by a lever 76 with a bell-crank lever 77, which is in turn connected by a link 77 with a crank 78, which operates a controller or governor 78, carried on the engine 42. In Fig. 4 I have shown a controller consisting of a rotary valve 78", the crank 78 being secured upon the stem thereof, so that by swinging said crank the valve may be partially rotated. The controller 78, as well as the intermediate mechanism for operating it from the rod 74, may, however, be of any approved construction suitable for varying the speed of the engine by longitudinal movement of said rod 74, the arrangement being such that when the rod 74 moves in one direction the speed of the engine is increased and when it moves in the opposite direction the speed is reduced. In Fig. 4 I have shown one form of construction for this purpose. As therein illustrated, the valve 78 is provided with passages 78, adapted to register with passages 78 which communicate with the steam-supply passage 78*, the arrangement being such that by rotating the valve 78 the area of the steam-inlet may be increasedor diminished and the speed of the engine varied accordingly. By this construction it will be seen that if the temperature of the furnace falls the speed of the conveyers is reduced and the cores are thereby subjected for a longer period of time to the lower temperature, as is necessary to properly bake them. Similarly, if the temperature of the oven rises the speed of the conveyers is increased, so that they are not subjected to the higher heat for so long a time, In a similar manner the temperature of the oven automatically controls the drafts, since the rod 74 is connected by chains 79 or other suit able flexible connections to the ash-pit doors or dampers 17, said chains running over pulleys 80, as shown in Fig. 1.

As shown in Fig. 1, when the rails 26 expand the upper end of the lever 72 moves in the direction indicated by the arrow in said figure. Consequently the rod 74 is moved in the same direction, thereby slacking the operating mechanism, While considerable chains 79 and lowering the damper 17. When the rail 26 cools and consequently contracts, the rod 74 moves in the opposite direction, consequently opening the dampers 17. A similar lever, connecting-rod, and chains are provided at both sides of the oven, but only one of said connecting-rods extends to the engine.

The green cores are carried to the baking apparatus by means of a conveyer 81, which receives the cores from the tables 82, at which they are formed, and conducts them to the carriers, as shown in Fig. 3. Said conveyer 81 is represented diagrammatically in Fig. 3 for the purpose of illustrating the fact that it is arranged to conduct the green cores from the place where they are formed to the carriers of the baking apparatus, and it should be understood that the shape and the diree-. tion of travel of said conveyer 81 may be varied to suit local conditions. By thus conveying the green cores to the baking apparatus they are handled only once-to wit, when they'are transferred from the conveyer 81 to the carriers of the baking apparatus-and thus are much less liable to injury than has heretofore been the case.

Instead of having the conveyers return over the oven, as shown in the drawings, any other equivalent construction may be em ployed.

From the foregoing description it will be seen that the oven is maintained at substantially a uniform temperature throughout and that such temperature is maintained at substantially a constant point by automatically variations in temperature are not apt to occur,

even slight changes atonce vary the speed of the carriers, so that the baking effect is practically invariable, the cores moving through the oven faster when it ishot and slower when Furthermore, by subjecting the it is cooler. cores to direct heat, as is the case in the apparatus described, they are baked more set forth, and I would say, further, that I have found by practicalexperience that a very important saving is attained by my im-' proved process, owing to the great reduction in the loss through damage to the cores as: compared with the results secured by meth-' ods heretofore employed.

For heating the oven I preferably employ coke or oil; but wood and coal may also be used, anthracite coal especially being quite a satisfactory fuel. The temperature employed should be somewhere between 400 and 700 Fahrenheit in order to produce the best results.

I have described in detail the apparatus illustrated in the drawings; but'I Wish it to be understood that my invention is not restricted to the details of construction of such apparatus, except in so far as such details are particularly claimed.

, That which I claim as my invention, and desire to secure by Letters Patent, is

1. In a core-baking apparatus, the combination of an elongated oven open at its ends, a carrier arranged to move through said oven from end to end,a plurality of direct-heat ing devices for heating said oven, means for. moving said carrier continuously through said oven, and means operated by the rise and fall of the temperature of the oven for regulating the speed of said carrier, substantially as described. V

3. In a core-baking apparatus, the combination of an oven, an endless carrier adapted to move through said oven, means for heating said oven, means for moving said carrier continuously through said oven, and means operated by variation in the temperature of the oven for varying the speed of said carrier, substantially as described.

4. In a core-baking apparatus, the combination of an oven, an endless carrier adapted to move through said oven, means for heating said oven, means for moving said carrier continuously through said oven, and means operated by an increase in the temperature of the oven for increasing the speed of the carrier and by the decrease in the temperature of the oven for decreasing the speed of the carrier, substantially as described.

5. In a core-baking apparatus, the combination of an oven, means for heating said oven, an endless carrier adapted to move through said oven, rails supporting said carrier, means for moving said carrier continuously through said oven, and means operated by expansion and contraction of one of said rails for varying the speed of the carrier, substantially as described.

6. A core-baking oven in combination with a carrier adapted to move through said oven, and means automatically operated by variation in the temperatureof the oven for varying the speed of said carrier, substantially as described.

7. A core-baking oven in combination with a continuously-moving carrier adapted to move through said oven, and means automatically operated by variation in the temperature of the oven for varying the speed of said carrier, substantially as described.

8. A core-baking oven having inlet and outlet openings at its ends, conveyer mechanism adapted to traverse said oven, passing through said openings, fire-boxes and chimneys communicating with the opposite end portions of said oven whereby heat is supplied and distributed uniformly throughout the oven, substantially as described.

9. A core-baking oven having inlet and outlet openings, fire-boxes at opposite sides of said oven and communicating therewith, and stacks at opposite sides of said oven near the opposite ends thereof, said stacks communicating with said oven, substantially as described.

10. In a core-baking apparatus, the combination of an elongated oven,a carrier arranged to move through said oven from end to end, means for moving said carrier continuously throughsaid oven, a plurality of fire-boxes for distributing heat uniformly throughout the oven, dampers controlling combustion in said fire-boxes,and means extending substantially from end to end of said oven and operated by variation in the temperature at any point in the length thereof for adjusting said dampers and thereby regulating the temperature of the oven, substantially as described.

11. In a core-baking apparatus for baking cores of difierent sizes, the combination of an oven having inlet and outlet openings, a plurality of endless carriers each traversing said oven and passing through said openings, and means for moving said carriers at different rates of speed, whereby cores of smaller sizes may be moved through the oven faster than those of .larger sizes, substantially as described.

12. In acore-baking apparatus, the combination of an oven havinginlet and outlet openings, a plurality of endless carriers movable through said oven, means for moving said carriers at difierent rates of speed, and means operated by variation of the temperature in the oven for varying the speed of said carriers, substantially as described.

13. In a core-baking apparatus, the combination of a baking-oven, means for heating said oven to a core-baking temperature, an endless carrier adapted to move through said oven to carry the cores into and out of said oven, said carrier extending a sufficient distance outside of said oven, to permit the cores to cool and harden on said carrier after baking, and means for operating said carrier, substantially as described.

14:. In a core-baking apparatus, the combination of an oven havinginlet and outlet openings, means for heating the oven to a corebaking temperature, a plurality of endless carriers extending through and a sufficient distance beyond the outlet-opening of the oven to permit the cores to cool and harden on the carriers after baking, and means for operating said carriers at different rates of speed, substantially as described.

nation of an oven havinginlet and outlet openings, a plurality of endless carriers arranged in parallelism and movable into, through and out of said oven, and means for moving said carriers, said carriers being arranged to extend for different distances outside of the oven, substantially as described.

17. In a core-baking apparatus, the combination of an oven, a core-carrier, and means operated by variation of the temperature in the oven for regulating the speed of said carrier, substantially as described.

18. In a core-baking apparatus, the combination of an oven, a plurality of carriers, means for moving said carriers at diiferent rates of speed, and means operated by variation of the temperature in the oven for regulating the speed of said carriers, substantially as described. I

19. A core-baking oven having direct-heat heating devices, apparatus for regulating the operation of said heating devices, and controlling means located in said oven and exposed to direct heat from said heating devices for actuating said regulating apparatus, substantially as described.

20. A core-baking oven having direct-heat heating devices, apparatus for regulating the operation of said heating devices, and controlling means in said oven and extending substantially from end to end thereof for actuating said regulating apparatus, substantially as described.

21'. In a core-baking apparatus, the combination of an oven open at its ends, a plurality of carriers movable side by side into, through and out of said oven, means for moving said carriers at different rates of speed, and means operated by variation in the temperature of the oven for varying the speed of said carriers, substantially as described.

22. In a core-baking apparatus, the combination of an oven havinginlet and outlet openings, a plurality of endless carriers arranged in parallelism and movable into, through and out of said oven, an end portion of one of said carriers extending beyond the corresponding end portion of an adjacent carrier, and means for moving said carriers, substantially as described.

ALFRED M. HEWLETT.

Witnesses:

A. G. ONEILL, CHAS. F. CULLoM.

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