US968507A - Ore-roasting mechanism. - Google Patents

Description

H. H. BLISS.-

v ORB ROASTING MECHANISM. APPLICATION FILED AUG. 19, 1902. RENEWED JAN. 21, 1910.

968,507. Patented Aug. 23, 1910.

ru': NORRIS PETERS cu., WASHINGYON, n c- UNITE HENRY H. BLISS, OF WASHINGTON, DISTRICT OF COLUMBIA.

ORE-ROASTING MECHANISM.

Specification of Letters Patent.

Patented Aug. 23, 1910.

Application filed August 19, 1902, Serial No. 120,254. Renewed January 21, 1910. Serial No. 539,310.

To all whom it may concern:

Be it known that I, HENRY H. BLIss, a citizen of the United States, residing at WVashington, in the District of Columbia, have invented certain new and useful Improvements in Ore-Roasting Mechanism, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to roasting furnaces of that type in which the ore is mechanically stirred on the hearth of the roasting chamber by a stirrer which is moved along the hearth by suitable mechanism and connections, such as a pair of flexible cables.

The invention relates more particularly to means for bringing the ore stirrer into operation or throwing it out of operation at will on one section or portion of the hearth independently of other sections or portions thereof.

It. further relates to operating the ore stirrer at will in either direction as may be desired while said stirrer, normally tending to take an inoperative position, is held in operative position while passing along that section of the hearth which it is desired to rabble.

It further consists in an ore stirrer, and an ore conveyer which may be employed to remove from the hearth ore that has been sufficiently treated, said stirrer and conveyer being independent of each other to the extent that while one of such appliances is being employed on the hearth the other is exterior to the roasting chamber.

It further consists in the parts and combinations thereof hereinafter set forth.

It will be understood that, while I have herein set forth the preferable and most eflicient. construction, for the purpose of fully illustrating the invention, my improvements may be usefully applied otherwise than in the particular arrangements of parts which are hereinafter described in connection with the accompanying drawings.

In said drawings-Figure 1 is a vertical longitudinal section of a roasting furnace embodying my invention, the operating mechanism being shown in elevation. Fig. 2 is a sectional view on line 22 Fig. 1. Figs. 3 and 4-. are detail views showing in elevation portions of the ore stirrer in different positions. Fig. 5 is a sectional view showing the reversing mechanism for changing at will the direction of movement of the ore treating devices. Fig. 6 is a side view of the furnace on a smaller scale. Fig. 7 is a sectional view showing a modified rabble finger and its support. Fig. 8 shows one of the conveying hoes. Fig. 9 shows a side View of one of the hoe arms, and two opposite side views of the ring which engages said arm. Fig. 10 is a plan view of said ring and a conveyer arm assembled on their cross shaft. Fig. 11 is a horizontal section through the reversing mechanism. Fig. 12 is a vertical sect-ion through one of the stops on the cable.

Referring to the drawings, A indicates the roasting furnace as a whole, having a relatively long and substantially horizontal roasting hearth a, bounded at the sides by ore retaining shoulders or elevations (4, preferably of fire brick; B the feeding hopper for the ore, which is to be understood as typical of any desired feeding means, the same being located at or near the rear end of the furnace; C the pit or receptacle below the hearth for receiving the roasted ore and located at or near the front end of the furnace; D the heat generating furnace located at the front end of the roasting chamber and adapted to deliver the products of combustion to and along the hearth a, E the exit flue for the products of combustion, having a communication at c with the rear end of the roasting chamber and connected with a stack (not shown) or other suitable means for taking away the said products, with the fumes generated in the roasting chamber; F the rabble comprising a carriage l movable longitudinally of the hearth a and guided by wheels 2 and rails 3, or equivalent supporting and guiding means, and comprising further an ore stirrer 4. The stirrer consists, in the construction shown, of a series of fingers 5 carried on a cross bar or shaft 6 of the carriage 1.

It will be understood that the fingers 5 may be individually movable toward and from the hearth while in operation, to pass over solid accretions on the hearth, as for instance by being connected with the shaft 6 by intermediate bearings, such bearings being turnable with the shaft to carry the fingers toward and from the hearth, and the fingers being upwardly movable in said bearings when they are in operative position, the

downward movement of the fingers being limited by pins or stops adapted to engage said bearings.

At a suitable point or points 7 on the carriage l is attached the draft device 8 of the rabble, in this instance a pair of flexible cables passing around wheels or pulleys 9 and 10 at the ends of the furnace. The wheels 10 are fixed on the shaft 11 actuated from a motor 12.

At a point remote from the carriage 1 is arranged a similar carriage 13 having supporting wheels 14 and a cross bar or shaft 15 on which are arranged ore conveying means consisting preferably of a series of individually movable hoes 16 arranged when in operative position to form a substantially continuous conveyer blade or flight extending from side to side of the hearth a. The carriage 13 is arranged at such point relative to the carriage 1 that when the ore stirrer is in operation the conveyer will be exterior to the furnace chamber. The exterior travel of the appliance which is not in operation is accommodated by a track 17 arranged above the furnace parallel with the upper limbs of the cables 8.

Swinging doors 18, 19 are provided at the ends of the furnace chamber to permit the entrance and exit of the carriages 1 and 13. These doors are normally held closed by weights 20 connected with the doors, or with hinge shafts 21 to which the doors are fixed by arms 22. The doors have slots 23 for the passage of the cables, and are opened by the contacts of the carriages and closed by the action of the Weights. The hinge axes of the doors 18 and 19 are arranged so that the doors open downwardly, said axes being near the plane of the hearth.

The means for reversing the directions of movement of the cables and their carriages from the motor 12 may be accomplished by a reversal of the motor, but I prefer a reversing mechanism (Fig. 5 and Fig. 11) interposed between the motor and. the shaft 11.

2 1 is a countershaft having fixed thereon a worm gear This gear is driven continuously in one direction by a worm 26 fixed on the motor shaft 27. The motor shown is of the electric type, but a steam or other suitable engine may be employed.

28 and 29 are spur pinions loosely mounted on the countershaft, one gearing directly with a spur wheel 30 on the shaft 11, and the other gearing with a spur wheel 31 on said shaft through the medium of an idler 32.

33 is a friction clutch member rotary with the countershaft and movable longitudinally on the same by means of a shipping lever 34 so as to engage with either of the pinions 28 and 29. The latter are suitably concaved at 35 to be fitted by the clutch member 33.

It will be understood that by causing the actuation of the pinion 28 the rabble may be moved in one direction, and by causing the actuation of the pinion 29 it may be moved in the other direction along the hearth. lVhen the clutch member is in a central inactive position disengaged from both pinions, the two carriages will be left stationary, the lower one on a suitable support 36 or 37 exterior to the furnace, and the upper one on the track 17. In such case the ore is left undisturbed for the desired period of time.

Referring now to the means for throwing the ore stirrer into or out of action, 38 is a weight connected by arms 39 with the stirrer shaft 6 and arranged so as to normally hold the shaft and the fingers 5 in the position shown in Fig. 1. There are two transverse rows of such fingers attached along the shaft 6, the fingers of one row being at an angle to the fingers of the other row, as seen in Fig. 1.

40 is an arm attached to the shaft 6 and normally extending upward therefrom (Fig. and maintained in such position by the action of the weight 38 until the gravity of the latter is overcome. In this position both rows of the fingers 5 are above and clear of the ore on the hearth a. If the arm #10 be deflected either forward or backward one row or the other of the fingers 5 is brought into action on the hearth (Fig. 3). Various means may be employed for so moving the arm 10. I prefer deflecting or guide plates 11 arranged along the side of the furnace chamber and each extending for a certain longitudinal section of the hearth a. The plates 1 are independent of each other and the arrangement is such that any one of them may be brought into the path of the arm 40, in which case the longitudinal movement of the rabble for the length of said plate would be accompanied by a rabbling of the ore on that section of the hearth, and by reversing the direction of movement of the rabble by the mechanism shown in Fig. 5 the stirring of said ore in both directions may be continued as long as desired for its most efficient treatment. Also two or more of the plates 41 may be adjusted into the position shown in Fig. 3 so that the passage of the rabble will be accomplished by a stirring of the ore on the hearth sections which correspond with such adjusted plates,

while the ore on other sections of the hearth is left undisturbed. A convenient mounting of the plates 41 for the described adjustment is on longitudinal axes or pivots 42 near the side walls 13 of the furnace chamber which walls have ears or bearings 41 adapted to sustain such pivots.

45 is an operating handle or lever passing to the exterior of the furnace through a slot 46 by which the plates 41 may be tilted from the position shown in Fig. 4 to that shown in Fig. 3, and vice versa.

47 is a hook or latch adapted to confine the lever 45 with the plate 41 in operative position. Said plates are adapted to assume and maintain the inoperative position by their own gravity.

It will be understood that the side walls 43 of the furnace chamber may be suitably protected interiorly by fire brick or otherwise adapted to withstand the heat of the furnace.

The conveyer hoes 16 are arranged on the carriage 13, being connected to the shaft 15 thereon, said shaft having one or more arms 48 adapted to engage with the cam plates or deflectors 41. lVhen it is desired to remove from the roasting hearth the ore adjacent to the pit C, the plate 41 adjacent to that section of the hearth (at the left hand end in Fig. 1) is alone adjusted into operative position. The motor and the mechanism shown in Fig. 5 are then caused to carry the ore stirrer and its carriage 1 out through the door 18 at the forward end of the furnace and the carriage 13 with the ore conveyer into the rear end of the furnace through the door 19. The conveyer will remain inoperative until it reaches the said adjusted plate 41, whereupon it will have its hoes 16 depressed into operative position and will remove into the pit C the roasted ore from the foremost section of the hearth. Should the ore not be satisfactorily cleaned off or removed from this final section of the hearth into the pit at one movement of the hoes, they can be brought back, upon the reversal of the power devices, to again traverse this part of the surface, and this can be kept up as long as desired. After this final section of the hearth surface has been thus cleaned, the ore from the next section can be brought to it by lifting the cam plate or deflector 41 at the end of the series to its inactive position and letting down the second from the end, for thereupon as the hoe carriage or conveyer carriage moves toward the discharge pit C the hoes are brought into active position upon the hearth and the ore will be advanced over a section.

By following similar steps the ore can be carried from section to section successively until it has been advanced along the whole surface and until the newly introduced charge is reached at the hopper end. Then, if desired, the hoe or conveyer carriage can be again withdrawn from the furnace and the carriage 1 with the stirring or rabbling fingers can be again introduced and allowed to traverse the hearth as frequently, and

over as long a period of time, as may be desired.

The carriages 1 and 13 may be inverted as they pass to the upper track 17, around the wheels 9 and 10, or they may have such a pivotal connection with the cables 8 as to pass up and down between said wheels without turning over. I

In Fig. 7 is shown a connection of the stirring fingers with their shaft which allows of their individual movement away from the hearth to pass over solid accretions or other obstructions. Here the shaft is formed with vertical bearings 49 in which the fingers rest loosely. Cross pins 50, or equivalent shoulders in or on the fingers, limit their play.

The hoes 16 can have individual movement on their shaft 15. Each is carried by an arm 51 and a shank 59. Arm 51 loosely encircles shaft 15 which passes through eye 52. 53 is a ring secured to shaft 15 by pin 54, and having shoulders 55, 56. Arm 51 has shoulders 57, 58. The shoulders on the arm lie in the plane of those on the ring.

lVhen the hoe has descended to operative position on the hearth the shoulder 57 is at a distance from the shoulder 55 so that the arm 51 may move upward if the hoe should be forced up by any obstacle which might otherwise arrest the hoe. lVhen the shaft 15 is released to turn the hoes into inoperative position the shoulder 56 engages the shoulder 58 and lifts the hoe. The yielding, just described, of the hoe, occurs, if necessary, when it is being advanced by the shaft 15 and is acting as a conveyer. Vhen it is moving in the opposite direction the arm 40, engaging with one of the cam-like or deflecting bars 41 acts to hold the hoe out of engagement with the ore on the hearth, it in the present construction elevating the hoe to a position higher than its intermediate one, as shown in Fig. 8.

In order to be able to rabble continuously, that is, to have the rabbling device move up and down interrupted only by the reversals of its movements, and have its traveling continue from one end of thehearth to the other, I prefer to combine with it a reversing mechanism which will act automatically and also devices by which reversal can be effected by the operator at his discretion and option.

The lever 67 which shifts the clutch 34, has an arm 68, 69, the two parts of which are connected together by a pivot at 70. The arm 69 is in proximity to one of the cables 8, and the latter is provided with tripping devices 71, 7a, which are detachably and adjustably secured to the cables. These trippers 71, 72, can be placed at such a distance apart as to cause the rabble to move a short distance in one direction over any section of the hearth desired, and then a short distance in the opposite direction over the same section; or they can be placed farther apart so that the section of the hearth acted upon shall be proportionately longer. And as stated, they can be so arranged as that the rabble shall move from one end of the hearth to the other at each traverse. For instance if the operator should desire to have the rabble act upon the entire length of the hearth except that portion which is adjacent to the receiving pit C, (electing to leave the ore on that section undisturbed in order that it may be sintered or otherwise affected) he puts into operative position all of the cam-like or deflecting devices at 41 except that which is over the last section of the hearth. Then if the tripping de vices at 71, 72 be properly set, and if power be imparted to the cables, the rabble fingers will move from the right hand end of the hearth to the left-hand end and will stir the ore over all of the sections except the last one, for the deflector etl at the latter being out of action, the rabble fingers will rise from the surface of the hearth and leave the ore in that region undisturbed; and then when the tripper 72 strikes the lever at 67, GS, (39, and throws the clutch into its other engagement, the cables will be reversed and the rabble carriage will be returned, it still passing inactive over the end hearth section but resuming action again at the next section and continuing in action to the right-hand. end of the furnace. But should the operator desire to act upon only the second, the third or the fourth (from the left-hand end) section of the hearth surface while the trippers 71 and 7 2 remain in the same positions, it is merely necessary to raise to their inoperative positions those cam plates or deflectors ll which are adjacent to the sections where no rabbling or stirring is to occur.

Should it be desired at any time to bring the rabble carriage out from the furnace chamber, this can be done by throwing the pivoted part 60 of the clutch lever out of the path of the tripper 71, for thereafter the outward travel of the carriage 1 will continue until it reaches the exterior space or chamber at 37, whereupon the operator, by hand, shifts the clutch lever and clutch to their neutral positions thus stopping the carriage propelling devices. And the rabble carriage can be retained thus outside of the furnace for the purpose of cooling it, for repairing or any other purpose.

Many times the operator or an assistant is able to ascertain, by inspection through windows at 7 3, or otherwise, the character of the work proceeding in the furnace and the condition of the different parts of the ore mass, and desires to control the movements of the rabble carriage 1 and of the hoe or conveyer carriage 13 entirely at his own election and option, and at such times a mechanism having the features herein described can be used, for he can connect or disconnect the power devices and the carriages and can reverse their movements entirely independently of the automatic reverse devices. Hence he is able to agitate or stir the ore on one partor another of the hearth at his discretion, and is also able to advance it as he sees fit.

Heretofore it has been generally the practice when mechanical rabbles have been used to have the parts so constructed and arranged that whatever action upon the ore is commenced and effected at one end of the hearth must be carried on uniformly to the other end, the devices being entirely mechanical and power-driven and so arranged as to be beyond the option or control of the operator. And as a result, and as is well known, furnaces with mechanical rabbles have never been found to be equal to those where hand rabbling is practiced, with respectto the roasting. The automatically and continuously acting rabble devices stir and advance the material with uniformity and continuity. But it is well known that some ores at certain stages of the roasting require longer heating and at other stages less heating than others. Again, it is well known that it is desirable to have ores of many sorts sintered prior to their final delivery, and this sintering is interfered with, in fact practically thwarted, by the mechanical rabbles heretofore in use, because of their acting uniformly upon the ore from one end of the hearth to the other. It is desirable after the ore has been exposed to the heat upon the preliminary sections of the hearth, that it should for a comparatively long period remain at rest upon the final section in order to attain certain beneficial results. And this is readily accomplished by the present devices.

1 am also aware that one important step here provided for has been heretofore taken in this art, namely, this, that the operator has been provided with hand controlling and reversing mechanism whereby he can predetermine those sections of the hearth over which the rabble shall be active; but this, although an importantadvance and improvement, depends entirely upon frequent visual inspections and exercise of discretion as to when and where the stopping of the action of the rabble shall occur and where the reversal of its movements shall commence, and the effecting of the reversal at a remote point, namely at the engine or motor.

With amechanism like the present all the advantages of the improvements last referred to are preserved and others are attained, for means are provided whereby the necessity for frequent inspections of the fur nace is obviated and the operator can be freed from exercising hand movements of reversal. The rabble here may travel any distance whatever over the hearth and yet be prevented from affecting any predetermined or desired parts thereof.

The present apparatus is not limited to a reciprocating movement of the rabbling devices. They can be carried around and around instead of to and fro as above described. In such case the trippers 71 and 72 are removed and the carriages 1 and 13 are provided with ore engaging devices similar to those generally in use heretofore, that is to say, devices capable of not only turning over or stirring the ore but also of advancing it somewhat at each action. As the carriages successively enter the furnace they are caused to operate on the one hand or to be inactive on the other, by bringing into working position the cam-like or deflecting devices n at points where the stirring or turning of the ore is to be effected, or by leaving these parts 41 in their inoperative position. If the final section of the hearth is to be left undisturbed tem porarily the deflector 41 over that section is left in inactive position, and consequently the continuously advancing rabbling devices will, one after the other, when they reach said section be automatically raised from the hearth, and the ore thereon will not be affected, until the sintering or other desired result has been attained.

It will be seen that, while all of the fea tures of the present invention do not depend upon it, the agitating of the ore is an action quite separate from the advancing of it; that is to say, the rabbling fingers 5 being very narrow in transverse dimensions merely move through the ore layer or mass on longitudinal lines acting to expose new particles and masses without pushing them along to any material extent, and consequently the extent to which the ore shall be treated during the different successive periods of time respectively can be accurately controlled and regulated. Then when the function of advancing is to be attained it can be done seperately from the agitatin and accomplished quickly by bringing into operation the conveyer hoes which are constructed materially differently from the agitating fingers. In this respect the present mechanism differs radically from the earlier ones which employ ore engaging devices of a character such that they were expected to not only effect the stirring of the ore but also, at each action, to advance it somewhat. These earlier devices have included both rotary plows or inclined blades connected to a revolving shaft and also rectilinearly reciprocating bars, triangular in horizontal section, each having the apex of its prism situated toward the receiving end of the hearth and the base part directed toward the discharge end, so that as it moved toward the former end it would tend to plow through or turn up the ore, and as it moved in the opposite direction would act to push a quantum of the ore mass along. l/Vith the present device, these two functions being separated as widely as possible, superior results are attainable for the reasons above referred to.

I am also aware of the fact that it has been proposed to employ a step by step rotating shaft provided with two diametrically opposite sets of blades or shovels and combined with fixed tripping devices, one at one end of the hearth and the other at the other end, and so arranged and related that when the carriage which reciprocates longitudinally of the hearth reaches the delivery end of the latter the trip device turns the two sets of blades, plows or hoes to the horizontal diameter of the shaft, that is, to an inactive position and at or about the same instant the travel of the carriage is reversed and it moves back to the opposite end of the hearth with the plows or shovels in their inactive position; and when the opposite or receiving end is reached the fixed tripping device at that line brings one of the sets of plows down to the working position near the hearth in which position they remain after reversal and until they again reach the trip device at the other end. That is to say, this proposed mechanism acts upon the ore when traveling in one direction only, and its action is to shovel material along or advance it while turning it to some extent, as above described. But the difference, upon a comparison with the present construction will be readily understood, as the tripping devices inside of the furnace in this case are on transverse lines between the ends of the layer or mass of ore on the hearth, and moreover they are adjust-able tripping devices so that the regions of working for the rabbler can be varied at will.

Of course it will be understood that in many respects the parts which I have presented in the drawings are indicated more or less conventionally though in such way as to be readily understood, by one skilled in the art. For instance the clutch at 34 is shown as a double friction clutch movable from one of the wheels 28, 29 to the other.

It is a well known practice to combine with such clutches means for causing them to move from one limit of their travel to the other, as for instance say a vibrating weight which is brought to thevertical by the tripping devices and then carries the clutch on through its travel. A toothed clutch instead of a friction clutch can be added if preferred.

hat I claim is:

1. In an ore roasting mechanism, the combination, with the hearth, of the carrying mechanism, the longitudinally movable ore 13% stirring devices, and means adjustable at will for bringing the ore stirring devices into and out of action while they are traveling over the hearth without changing their longitudinal movements, substantially as set forth.

2. The combination with an ore roasting hearth, of the carrying mechanism traveling longitudinally of the hearth, and the oreengaging devices thereon adapted to have then operative ends sustained in either of two positions relatively to the hearth while they are traveling above it, and means adjustable at will situated on transverse lines between the ends of the ore mass on the hearth for automatically moving the ore engaging devices from one to the other of the said two positions while they continue to advance longitudinally in one direction or the other along the hearth, substantially as set forth.

3. In an ore roasting mechanism, a roast ing hearth extending substantially continu ously in one direction and adapted to have the ore thereon treated differently on the several sections thereof respectively, in combination with ore stirring devices arranged to travel over the said hearth, and means for causing the said stirring devices to engage with the ore upon one section of the hearth and to hold them in inoperative position above the ore upon an adjacent section, substantially as set forth.

ft. The combination with the roasting hearth of ore stirring mechanism movable longitudinally of the hearth, means connect ed with. the stirring devices for moving them longitudinally, devices movable at will from an active to an inactive position and sup ported by the furnace for throwing the stirring devices into or out of action while moving longitudinally of the hearth, substantially as set forth.

5. In an ore roast-ing furnace, the combination of a hearth, ore engaging devices moving longitudinally along the hearth and movable relatively thereto into operative and inoperative positions, and adjustable means within the furnace for moving the said ore engaging devices into one or the other of their said positions, substantially as set forth.

6. The combination with the series of ore stirring devices each movable separately and all movable together toward and from the hearth, of the adjustable devices within the furnace for automatically moving all of the said ore stirring devices toward or from the hearth, substantially as set forth.

7. In an ore roasting mechanism, the combination of a hearth, ore engaging devices movable along the hearth and movable to ward and from the hearth into operative and inoperative positions, means for holding the ore engaging devices in operative position as they pass over a predetermined section or sections of the hearth and sup plemental means for holding them in in operative positions as they pass over other sections of the hearth, substantially as set forth.

8. The combination with the ore roasting hearth, of the propelling mechanism, a set of transversely narrow ore engaging fingers or plates moved by said mechanism longitudinally of the hearth and constructed substantially as set forth for stirring the ore without advancing it, means for automatically bringing the said ore engaging devices into or out of action upon the ore, and a supplemental set of ore engaging devices consisting of transversely arranged plates relatively wider than the said fingers or agitating plates and constructed substantially as set forth for advancing the ore bodily longitudinally of the hearth.

9. The combination with the ore roasting hearth, of the propelling mechanism and the two independent sets of ore engaging devices propelled thereby, one constructed substantially as set forth with a row of transversely narrow fingers for stirring the ore without advancing it, and the other having a transverse row of relatively wide shovel like plates or scoops for advancing the ore without stirring it, and means for automatically bringing the ore engaging de vices of either of said sets into or out of action on the ore.

10. In an ore roasting mechanism, the combination with the roasting hearth, of a set of stirring devices, means for supporting the stirring devices, means for propelling the stirring devices longitudinally of the hearth, a set of ore conveying or advancing devices, means for supporting the ore advancing devices independent of the support for the stirring devices and connected to the propelling mechanism, substantially as set forth, whereby the ore advancing devices can be situated outside of the furnace when the stirring devices are inside.

11. In an ore roasting mechanism, the combination with the roasting hearth, and the ore stirring devices, of the power mechanism, the propelling devices connecting the stirring devices with the power mechanism, means for automatically stopping the longitudinal advance of the ore stirring devices at any desired point along the hearth, and means adapted to be actuated by hand for regulating the longitudinal movement of the ore stirring devices, substantially as set forth.

12. In an ore roasting mechanism, the combination with the roasting hearth, of the ore stirring devices, the means for supporting the stirring devices, and the means for transporting the stirring mechanism longitudinally of the hearth, the power mechanism, devices for automatically controlling the direction of the longitudinal movement of the stirring devices caused by the power mechanism, and adapted to be thrown out of action, and means for controlling said movements by hand, substantially as set forth.

13. In an ore roasting furnace, the combination of a hearth, ore engaging devices movable along the hearth and adjustable into operative and inoperative positions, and a series of several adjustable tripping devices within the furnace at different points along the hearth for adjusting the ore engaging devices into either of said positions, substantially as set forth.

1%. In an ore roast-ing furnace, the combination of a hearth, ore engaging devices movable along the hearth and adjustable into operative and inoperative positions, means for maintaining the ore engaging devices in operative position as they pass over a certain section of the hearth and in inoperative posit-ion as they pass over another section of the hearth, and mechanism for automatically causing the reciprocation of the ore engaging devices in the furnace.

15. In an ore roasting furnace, the combination of a hearth, ore engaging devices adapted to be reciprocated in the furnace over said hearth and adapted to be moved toward or from the hearth into operative or inoperative positions, automatically acting means for maintaining the ore engaging de vices in operative position as they pass over a certain section or sections of the hearth and in inoperative position as they pass over another section or sections of the hearth, and mechanism acting automatically to cause the reciprocation of the ore engaging devices in the furnace.

16. In an ore roasting furnace, the combination of a hearth, ore stirring devices operable on said hearth, and normally held in inoperative position, power mechanism for moving said stirring devices along the hearth, and means within the furnace between the ends of the path of the stirring devices for throwing them into operative position.

17. In an ore roasting furnace, the combination of a hearth, ore stirring devices operable on said hearth, and arranged to move by gravity into an inoperative position, power mechanism for moving said ore stirring devices along the hearth, and means for causing the stirring devices to assume an operative position on a certain section of the hearth.

18. In an ore roasting furnace, the combination of a hearth, a row of transversely narrow fingers adapted to serve as an ore stirring means operative on said hearth, a row of transversely wide scraping plates adapted to serve as an ore conveying means operative on said hearth, an endless power device connected with said stirring means and with said conveying means, the stirring means and conveying means being situated at different points on said endless power device and otherwise independent of each other, and mechanism connected with said power device for operating the latter in either direction.

19. In an ore roasting furnace, the combination of a hearth, ore stirring means and ore conveying means operative on said hearth, an endless power device connected with said stirring means and with said conveying means, the stirring means and conveying means being situated at different points on the power device and separately introducible into the furnace for different operations on said hearth, the stirring means having a series of transversely narrow fingers and the conveying means having a series of transversely wide ore engaging plates and mechanism for actuating said power device.

20. In an ore roasting furnace, the combination of a hearth, ore stirring means and ore conveying means separately operative on said hearth, an endless power device connected with said stirring means and conveying means, the stirring means and conveying means being situated at different points on the power device, said stirring means having a row of transversely narrow ore engaging fingers and said conveying means having a row of transversely wide ore engaging plates and reversible power mechanism connected with said endless power device.

21. In an ore roasting furnace, the combination of a hearth, ore stirring means and ore conveying means separately operative on said hearth, said stirring means having a row of transversely narrow fingers and said conveying means having a row of transversely wide shovel like plates a power device connected with said stirring means and with said conveying means, the stirring means and the conveying means being situated at different points on the power device and separately introducible into the furnace for different operations on said hearth, and reversible power mechanism for actuating said power device, whereby either the stirring means or the conveying means may be separately introduced into the furnace and the stirring means moved in either direction on said hearth.

22. In an ore roasting mechanism, the combination with the hearth, of the carrying mechanism, the longitudinally movable ore conveying devices, and means adjustable at will for bringing the ore conveying devices into and out of action along any desired section or sections of the hearth while they are traveling over the hearth without changing their longitudinal movements.

23. In an ore roasting mechanism, the

24-. In an ore-roasting mechanism, the

combination of a roasting hearth, longitudinally movable ore-engaging devices, propelling mechanism for said ore-engaging devices, and adjustable means for automatically throwing said ore-engaging devices into and out of action while they are traveling along the hearth without changing their 1011- gitudmal movement, whereby they Wlll act upon the ore on one portion of the hearth and leave that on the remainder of the hearth undisturbed.

25. In an ore-roasting machine, the com bination with a roasting hearth of a rabble mechanism adapted to travel along the hearth and comprising a set of ore-engaging devices each relatively thin on lines transverse to the hearth and adapted to stir the ore and a set of ore-conveying devices adapted to engage the ore and move it along the hearth in contradistinction to merely stirring it, propelling means for said rabble mechanism, and means for automatically moving either of said sets of ore-engaging devices into or out of operative position relative to the hearth, whereby they may act upon the ore upon a given portion of the hearth and leave undisturbed the material on the remainder of the hearth.

26. In an ore-roasting machine, the combination with a roasting hearth of a rabble mechanism adapted to travel along the hearth and comprising a set of ore-engaging devices each relatively thin on lines transverse to the hearth and adapted to stir the ore and a set of ore-conveying devices adapted to engage the ore and move it along the hearth in contradistinction to merely stirring it, propelling means for said rabble mechanism, means for automatically moving either of said sets of ore-engaging devices into or out of operative position relative to the hearth, whereby they may act upon the ore upon a given portion of the hearth and leave undisturbed the material on the remainder of the hearth, and means for reversing the direction of travel of the said rabbling mechanism.

27, In an ore-roasting machine, the combination with a roasting hearth of a rabble mechanism adapted to travel along the hearth and comprising a set of ore-engaging devices each relatively thin on lines transverse to the hearth and adapted to stir the Ore and a set of ore-conveying devices adapted to engage the ore and move it along the hearth in contradistinction to merely stirring it, propelling means for said rabble mechanism, means for automatically moving either of said sets of ore-engaging devices into or out of operative position relative to the hearth, whereby they may act upon the ore upon a given portion of the hearth and leave undisturbed the material on the remainder of the hearth, and means for automatically reversing the travel of said rabbling mechanism whereby it will operate above only the said given portion of the hearth.

28. In an ore-roasting mechanism, the combination of a roasting hearth, ore-engaging devices arranged to travel over said hearth, propelling mechanism for said oreengaging devices and automatically acting means for throwing the said ore-engaging devices into or out of operation relative to the hearth, and adapted to cause them to engage with the ore on one section of the hearth and adapted to hold them in inoperative position above the ore upon an adjacent section of the hearth.

29. In an ore-roasting furnace, the combination with a hearth, ore-engaging mech anism movable longitudinally of the hearth and adapted to be thrown into or out of action relative thereto, propelling mechanism for said ore-engaging mechanism, and

mechanism arranged along the hearth and adapted to be adjusted at will to automatically throw the said ore-engaging mechanism into or out of action while moving longitudinally of the hearth.

30. I11 an ore-roasting furnace, the combination of a roasting hearth, ore-engaging devices movable to and fro along the hearth and into and out of operative position, devices arranged along the hearth for automatically throwing said ore-engaging devices into and out of operation, propelling mechanism for the ore-engaging devices, and adjustable mechanism for automatically reversing the direction of travel of the said ore-engaging devices to cause them to reciprocate above any desired portion of the hearth.

31. In an ore-roasting furnace, the combination of an ore-roasting hearth, ore-engaging mechanism adapted to travel along the hearth and comprising a row of stirring fingers relatively narrow on lines transverse to the hearth and adapted to stir the ore without advancing it, and a row of shovellike plates or scoops adapted to advance the ore along the hearth in contradistinction to merely stirring it, propelling means for the ore-engaging devices, and means for automatically throwing either of said sets of ore-engaging devices into or out of operation relative to the hearth in order to cause them to act upon the ore along a section or sections of the hearth and to leave the material along the remainder of the hearth undisturbed.

32. In an ore-roasting furnace, the combi nation of a roasting hearth, ore-engaging devices movable to and fro along the hearth and adjustable into and out of operative relation thereto, means for automatically throwing said ore-engaging devices into and out of operation along various sections of the hearth, propelling mechanism for the said ore-engaging devices and means for automatically reversing the direction of travel of said ore-engaging devices adjustable to cause them to reciprocate above various portions of the hearth.

33. In an ore-roasting furnace, the combination of a hearth, ore-engaging devices movable along the hearth and arranged to move by gravity into an inoperative position relative to the hearth, propelling mechanism for said ore-engaging devices, and means for causing the said ore-engaging devices to assume an operative position along any desired portion of the hearth.

34. In an ore-roasting furnace, the combination of a roasting hearth, ore-engaging devices movable to and fro along the hearth and adjustable into and out of operative relation thereto, means for automatically throwing said ore-engaging devices into and out of operation along various sections of the hearth, and a flexible draft-transmitting device connected With said ore-engaging devices for propelling them.

35. In an ore-roasting furnace, the combination of a roasting hearth, ore-engaging devices movable to and fro along the hearth, propelling mechanism adapted to reciprocate the said ore-engaging devices along the hearth, and means for automatically reversing the direction of travel of said propelling mechanism and adjustable to cause it to reciprocate the said oreengaging devices above various portions of the hearth and to leave the material on other portions thereof undisturbed.

In testimony whereof I aflix my signature in presence of two Witnesses.

HENRY H. BLISS.

Witnesses N. CURTIS LAMMOND, F. S. ELMORE.

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