US2070911A - Control of operating mechanism for scotch hearths - Google Patents

Description

' Feb. 16, 1937. H, R, MaCMICHAEL 2,070,911

CONTROL OF OPERATING MECHANISM FOR SCOTCH HEARTI'IS Filed July 26, 1923 3 Sheets-Sheet 1 v anveutoz HUGH R. MACMICHAEL a g (Mime/13M CONTROL OF OPERATING MECHANISM FOR SCOTCH HEARTHS Feb. 16, 1937. H, R, MacMlcHAEL 2,070,911

CONTROL OF OPERATING MECHANISM FOR SCOTCH HEARTHS Filed July 26, 1923 3 Sheets-Sheet 3 jwuamtoz HUGH R MACMICHAEL I I a1g abtowmg iii Patented Feb. 16, 1937 UNETEE STATES PATENT OFFICE CONTROL OF OPERATING MECHANISM FOR SCOTCH HEARTHS Application July 26, 1928, Serial No. 295,420

8 Claims.

The invention relates in general to the art of metallurgy and, more particularly, to apparatus for completely mechanically operating a Scotch hearth.

According to one form of the invention a Scotch hearth is provided with a carriage which may be arranged to move continuously therealong and have mounted thereon various operating mechanisms, such as a mechanical poker, a mechanical shovel and a mechanical feeder, all operating upon the material in the hearth.

The poker may be adapted to enter the charge, poke it and level it down, causing parts thereof to be thrown on the apron of the hearth, in a manner similar to the present manual operation. If desired, a compensating movement may be provided so that the poker is substantially stationary with respect to the movement of the carriage while in the hearth.

The shovel may be arranged to operate upon the charge after the poker and may be arranged to travel over the charge, scraping the apron and flipping part of the charge up against the back of the hearth, forming a bank having the proper slope and condition for best smelting.

The feeding mechanism, may comprise a suitable charge container preferably feeding into a suitable conveyor which delivers the charge to the hearth. Suitable shaking mechanism may be provided to cause the charge to be fed and distributed in the desired manner. Suitable devices may be provided for controlling the distri bution of charge to different parts of the hearth.

For controlling the operation of the carriage and of a feeder, poker and shovel, suitable automatic control devices have been provided. In the modification disclosed the control device for the carriage may consist of suitable stops arranged on the ends of the carriage and a switch adapted to be thrown by the stops, the switch being positioned along the trackway. When the carriage reaches the end of its operating pass or trip the stop throws the switch, which reverses the motor, to drive the carriage back to its starting position.

For starting the individual mechanisms at substantially the starting ends of the furnace and for stopping them at substantially the ends of the furnace, a control rail is provided along which is adapted to roll individual control levers. Each of the mechanisms is provided with a suitable clutch which is controlled by the respective control levers for initiating and stopping the mechanisms at the proper times. devices are provided for stopping the poker and Also suitable shovel clear of thematerial in the furnace so that they are free to let the carriage travel back to its starting end.

A particular mechanical shovel which may be employed is disclosed in application Serial No. 196,304, filed June 3, 1927, a particular mechanical poker mechanism which may be employed is disclosed in'application Serial No. 200,523, filed June 22, 1927, and a particular mechanical feeder is disclosed in application Serial No. 200,524 filed June 22, 1927.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, 'in which Fig. l is a front elevation looking toward the rear of the furnace of a carriage equipped with the several mechanisms and controls;

Fig. 2 is a top section taken on the line 2-2 of Fig. 1 and illustrating the relative position of the hearth carriage, and control elements;

Fig. 3 is a detail of the poker compensating u mechanism; and

Fig. 4 is a section on the line 4-4 of Fig. 1 illustrating the structure of the mechanical shovel.

In the following description and in the claims parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Like reference characters denote like parts in the several figures of the drawings.

In the drawings accompanying and forming part of this specification, a practical commercial embodiment of the invention is shown, but as such illustration is primarily for purposes of disclosure, it will be understood that the structure may be modified in various respects without departure from the broad spirit and scope of the invention as hereinafter defined and claimed.

Referring now to the drawings, and more particularly to Figs. 2 and 4, so much of a Scotch hearth as is necessary to an understanding of this invention will be described. The Scotch hearth may comprise the usual basin or trough l, the trough being comparatively narrow and relatively long, as is well understood. At the front edge of the trough, an apron 2 is provided extending the length of the trough, the apron sloping forward and slightly downwardly. At the back side of the trough and extending the length thereof is a back made up of a block 3 having a suitable water space 4 therein for cooling, underneath which are suitable tuyeres 5 for supplying draft to the furnace, as is well understood in the art. Hoods denoted generally by l2 are provided, their lower ends being disposed close to the hearth efiiciently to catch the fume and gases. This construction is well known and no further description is deemed necessary.

Disposed in front of the hearth overhead is a pair of rails H on which the carriage runs. The carriage comprises a suitable frame work in which is journalled a pair of axlesB and I which have mounted thereon wheels 8 running on rails II. The carriage carries the mechanical poker 9, the mechanical shovel l0, and the mechanical feeder l3, which will be described in detail hereinafter.

Driving means for the carriage isshown best in Fig. 1. One axle 6 journalled to rotate in the carriage frame has fixed thereon the wheels 8 and also a spur gear IS. A suitable small electric motor I! may be provided having operative connection with the spur gear through a suitable worm and worm wheel reduction unit located within the housing l8, this reduction unit driving a small pinion l9 which meshes the spur gear IS. The motor I! may be of the type which is capable of running forward at a certain speed and running backwards at an increased speed.

For driving the poker, feeder, and shovel mechanisms a separate electric motor 20 is provided mounted on a suitable supporting partof the frame. The main drive shaft 2| is suitably journalled in the frame, the drive shaft having a large gear 22 mounted thereon. An intermediate'shaft 23 is mounted in suitable bearings between the motor 28 and the main shaft 2|, this intermediate shaft having a large gear 24 meshing with the small gear 25 on the motor shaft, and also having a small gear 26 driving the large gear 22 on the main shaft, to give the necessary'and desired speed reduction to the main shaft.

The main shaft 2! may have loosely mounted thereon a composite gear 2'! made up of a spur gear 28 and bevel gear 29 fixedly secured to each other. The spur gear 28 drives a larger gear 35. located on the rabble shaft 3 l A suitable clutch mechanism 32 controlled by suitable linkage may be provided for selectively connecting and disconnecting the composite gear 21 to the main shaft 2|.

Mounted in a pair of suitable bearings 33, (Fig. 3) supported'by the frame is a crank-shaft 34 having a pair of crank arms 35 and a crank pin 36 therebetween, and an overhung bevel gear 31 meshing with the bevel gear 29 on the main shaft.

Located below the main shaft is the rabble shaft 3! the rabble shaft being supported in suitable bearings on the framework. In overhung relation on the end of the rabble shaft is a crank 38 for driving the poker device. Also mounted on the rabble shaft 3| is the large gear 38 having feather keyway engagement 4'! with the rabble shaft, as shown'best in Fig. 3, the gear being fixed longitudinally between suitable bearings 39; Also mounted on the rabble shaft is a pair of spaced collars 40-between which is mounted a sleeve 4| having trunnions 42 projecting therefrom.

Between the crank-shaft 34 and the rabble shaft 3! is a fulcrum bracket having a pivot pin 43 on which is pivoted a lever 44, the lower end of the lever being slotted to engage the trunnions 42, the upper end of the lever being provided with a slot 45 in which the crank pin 36 works.

Supported by the carriage frame and near the front edge of the trough I (Fig. 2) is a support or fulcrum point 46 for the poker 9, this support allowing the poker a motion bodily back and forth in the direction of carriage travel. The poker 9 is provided with a projecting crank pin 50 which is journalled in the crank 38, the crank being provided with a sutable counterweight to counterbalance the weight of the poker.

Referring now more particularly to Figs. 1, 2 and 4 for a description of the shovel mechanism, the main shaft 2| has loosely mounted thereon a spur gear 55. A suitable clutch device 56 operated by suitable linkage is provided for connecting and disconnecting said gear 55 and the main shaft. Below the main shaft the shovel shaft 51 is suitably journalled in the framework of the carriage and has mounted thereon a gear 58 meshing gear 55 and a cam wheel 59. The cam wheel has secured thereto a crank pin 15 having a grooved roller 16 journalled on the end thereof.

The framework of the carriage is provided with a pair of lugs or ears to which the impeller arm 60 is pivotally connected by pivot 6! and a second pair of spaced ears to which a composite lever 62 (Fig. 1) is pivoted by pivot 63. The framework has a bracket member 64 having aligned openings in which is slidably mounted a follower rod 65 having at its lower end a roller 56 engaging the cam surface.

The follower rod 65 is provided with a suitable abutment 68 between which and the plate 58 is disposed a coil spring in, this coil spring acting to continuously urge the follower rod against the cam surface. The plate 69 is secured in fixed relations to the bracket member by a pair of rods ll disposed on either side of the follower rod.

As shown, the impeller arm 66 is curved at its upper end and generally straight for the rest of its length and has secured to one side thereof a pair of spaced lugs 12. A pair of spaced ways or guides 13 is secured to the lugs, these ways or guides being curved, as shown in Fig. 4, to aid in giving the desired peculiar motion to the shovel blade 14. The grooved roller 76 on the end of the crank pin is disposed between these ways.

Pivoted at the lower end of the impeller arm is a shovel arm 17, this arm comprising a body member having an opening in its middle portion, forming branches (Fig. 2) between which the lower end of the impeller arm is disposed. A suitable pivot bolt '18 threads the branches and the impeller arm. The front end of the body is suitably forked, and between the prongs of the fork the lower end of the elevating link 75 is suitably pivoted by a pivot bolt 88. The rear end of the shovel arm is provided with the blade M of the shovel which extends longitudinally of the furnace a substantial extent and has a slightly back-curved lower end 8%, as shown in Fig. 4.

The upper end of the elevating link l9 has a suitable loose universal connection with the composite lever 52 to allow the swinging movement of the elevating link back and forth and the up-anddown movement imparted thereto by the composite lever. The follower rod 65 has a pivot 83 which works in a slot in the composite lever 52 so that the reciprocating movement of the follower may be imparted to the composite lever.

Referring now to the feeder, the carriage frame supports a suitable charge container or hopper I25 intowhich the charge, which may be premixed ore, fume (in the case of lead smelting) and fuel finely divided, may be delivered in any desired way. The hopper I25 tapers downwardly as shown in Figs. 1 and 2. The bottom wall of the hopper is closed and the side has an opening delivering charge to an inclined chute I26, this chute extending backwardly and slightly downwardly toward the furnace. The end of the chute I26 is cut at an angle of about 45 so that the charge which is fed down the troughs I28 may be fed and distributed throughout the width of the hearth as shown in Fig. 2.

The chute I26 is suitably mounted on the frame by suitable loose or spring mountings (not shown) so that a considerable play or shaking action may take place between the chute and the carriage frame, as hereinafter described more in detail. Depending from the chute I26 is a pair of bearings in which is journalled a shaker shaft I3I having unbalanced weights I32 fixed thereon. Suitable means (not shown) may be provided for'individually controlling the flow of material down the several troughs.

A sprocket I37 may be loosely mounted upon the main shaft 2|, and a clutch I38 may be provided for connecting and disconnecting the sprocket to the main shaft. An intermediate shaft I39 may be provided having a small sprocket I49 and a large sprocket I4I thereon, and a chain I42 may connect the smaller sprocket with the sprocket I3I on the main shaft. A sprocket I43 may be provided on the shaker shaft and a chain I44 may connect this sprocket with the larger sprocket I l I, on the intermediate shaft I 39. It will be seen that this sprocket and chain arrangement operates to speed up the shaker shaft I3I. It will be understood that the relatively low speed of the main shaft 2| is desirable for driving the rabbling and shoveling mechanism.

Disposed along the hearth is a control rail 99 having its ends 9I sloping away from the carriage. For controlling the several clutches 32, 56, I38, individual control levers 92, 93 and 94 respectively having rollers at their free ends for rolling along the rail 99 are provided. These control levers are pivoted to suitable parts of the carriage frame and have suitable control linkages connecting the several clutches.

In the case of the poker the lever 92 is pivoted to the frame by pivot 96 and connected by a rod 91 to a lever 98 pivoted to the frame by pivot 99. Another lever I99 is pivoted tothe lever 98 and is also pivoted to the frame by pivot I9I. Lever I99 has at its end a stop bar I92 slidable in guide I94 and adapted to be positioned in the path of an abutment I93 on the gear 39 to insure stopping the poker free of the charge. The lever 98 is suitably pivoted to clutch 32 by pivot I95 tooperate it against its spring I36.

In the case of the shovel, the lever 93 is pivoted to the frame by pivot I96, .and connected by a member I91 to lever I98 pivoted to, a frame by pivot I99. Another lever H9 is pivoted to lever I99 and pivoted to the frame by pivot III. A stop bar (omitted for sake of clearness) adapted to slide in a guide is pivoted to lever II9, the stop bar being adapted to move into the line of abutment II2 on gear 58 in a manner similar to that described in connection with that of the poker. The lever I98 is connected to the clutch 59 in a manner similar to the case of the poker.

In the case of the feeder, the control lever 94 is pivoted to the frame by pivot II4 which in turn is connected to an upright lever II5, this in turn being connected to the clutch I38 in a manner similar to that described in connection with the poker.

Thus it will be seen as the carriage begins its operating trip in the direction of the arrow X in Figure 2, the several control levers will separately engage the control rail, throw in the separate clutches against their springs, and operate the several mechanisms. The poker will first be started and its control lever is so positioned that the poker will start at substantially the end of the hearth. Similarlyywhen the carriage advances a little further, the control lever for the shovel will engage 'the control rail and start the shovel workingat.substantially the end. of the hearth. Likewise, when the carriage moves a little .further,'the control lever for the feeder, will engagethe control rail andstart' the feeder feed ing when it is at substantially the end of the hearth.

As the carriage travels along in the direction of the arrow X, each of the operating mechanisms operates on the charge, as hereinafter described, and when the carriage reaches near the end of its operating trip the several control levers successively ride off the end of the control rail and stop the operation of the mechanisms. As the control levers ride off the end of the rail the several clutch springs cause the clutches to disengage and cause the control levers to swing to the position illustrated by control lever 92 in dotted lines.

As the last control lever rides off the control rail, the abutment II6 on the carriage contacts the switch lever II'I to reverse the motor I! on the carriage to move it back to its initial end, at an increased speed if desired.

The end of the poker will describe a closed path and the charge will be broken up and leveled down and parts of the charge thrown on the apron, all as is described in the above co-pending applications. The top of the charge, when thus leveled down, under some conditions is illustrated by line 86 in Fig. 4.

The mechanism will cause the shovel to execute a movement illustrated by the dotted line and arrows indicated by 8'! in Fig. 4. This shovel will scrape the apron, as shown, and push the charge back, forming the bank which, under some conditions may be illustrated by the line 88 in Fig. 4. The shovel will travel slowly at the front of the hearth but will receive a sudden flip about halfway across the'basin which flips the material up against the back of the hearth and causes it to roll forward by gravity, providing a selective action, as explained in the above co-pending applications.

The slope of the chute I26 is not sufficient to cause the charge to flow down unless the chute is shaken. When the clutch I38 is engaged. it will be seen that the driving mechanism will cause the chute to shake or vibrate, the loose spring mountings allowing this action. As the carriage travels on its operating trip, the charge will be fed down the troughs I28, and its distribution on the hearth will be controlled by the amounts allowed to flow down the troughs I28. The arrangement is such that very accurate control of spreading may be obtained, and by premixing the fuel, ore and fume, a very efficient smelting action may be obtained.

When the poker engages the charge, it breaks up the charge and levelsit down and throws part of it on the apron, similar to the manual operation. The shovelfoll'owing. pushes the charge back, flipping part of it against the furnace back and causing part. of it to roll. forward with a selective action. The larger particles rollforward the farthest and particles of slag roll down on the apron, from which they can easily be removed. The feeder following the shovel feeds the charge (which, in the case of lead ores, may be pre-mixed fuel, ore and fume) in such manner as to get the proper distribution across the width of the hearth.

By means of the carriage with. its above described operating mechanisms and its automatic control features, a Scotch hearth type of furnace or other furnace may be operated substantially completely automatically without manual operation. One man may run a number of carriages and it is only necessary to adjust, from time to time, the stroke of the shovel or poker or the feed of the feeder to take care of changing conditions. The automatic mechanism furthermore insures the proper starting and stopping of the individual operating mechanisms and proper operation of the carriage. By the use of the present: invention the operation. of a Scotch hearth may be made substantially uniform and when the best operating conditions have been obtained the device insures continuance of these conditions.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is: a

1. In combination with a hearth, a trackway along said hearth, a carriage onsaid trackway, a control rail along said hearth and having its ends sloping away from said trackway, an operating mechanism on said carriage for treating said hearth, a source of power on said carriage, a clutch between said source and operating mechanism, a control lever pivoted to said carriage, linkage connecting said lever and clutch, said lever engaging and trailing at an angle to said rail on the operating trip of said carriage to close the clutch against the action of the clutch spring, and means for reversing the carriage at the ends of its operating and return trip's, said spring causing said lever to swing to an'opposed position at the end of the operating trip so that it may trail at an angle to said rail on the return trip.

2. In combination with a hearth, a trackway along said hearth, a carriage on said' trackway, a control rail along said hearth and having its ends sloping away from said trackway, an operating mechanism on said carriage for treating said hearth, a source of power on said carriage, a clutch between said source and operating mechanism, a control lever pivoted to said carriage, linkage connecting said lever and clutch, said lever engaging said rail on the operating trip of said carriage to close the clutch against the action of the clutch spring, and means controlled by said control lever for insuring that said mechanism stops clear of the hearth.

3. In combination with a hearth, a track along said hearth, a carriage on said track, a plurality of individual operating mechanisms mounted on said carriage for treating said hearth, means for automatically reversing the direction. of carriage travel when it reaches the end of its operating and return trips, means for individually automatically starting and stopping each mechanism at substantially the ends of the hearth on the operating trip ofv the carriage, and means for stopping certain of said mechanisms clear of the hearth at the end of the operating trip of the carriage.

4. In combination with a hearth, a trackway along said hearth, a, carriage onsaid trackway, a control rail along said hearth and having its endssloping away from said trackway, an operating mechanism on said carriage for treating said hearth, a source of power on said carriage, aclutch between said source and operating mechanism, a control lever pivoted to said carriage, linkage connecting said lever and clutch, said lever engaging said rail on the operating trip of said carriage to close the clutch against the action of the clutch spring, and means for reversing the carriage'at the ends of its operating and return trips.

5. In combination with a hearth, a track along said hearth, a carriage on said track, a poker mechanism, a shovel mechanism and a feeder mechanism all mounted on said carriage for treating said hearth, means for automatically reversing the direction of carriage travel when it reaches the end of its operating and return trips, means for automatically starting and stopping each mechanism at substantially the ends of the hearth on the operating trip of the carriage, and means for stopping said poker and shovel mechanisms clear of the hearth at the end of the operating trip of the carriage.

6. In combination with a Scotch hearth having a longitudinally extending basin, mechanical operating mechanism comprising overhead tracks extending along said hearth, a carriage suspended from wheels mounted on said tracks, a control rail extending along said hearth having ends inclined away from said carriage, means for driving said carriage including a separate motor, a reversing switch having a lever disposed along said tracks, stops at the ends of said carriage engageable by said lever to change the direction of carriage travel, a second motor, a main shaft, reducing gearing between said second motor and main shaft, poker mechanism including a poker adapted to enter the fire, shovel mechanism including a shovel adapted to enter the fire, feed mechanism mounted on said carriage, first, second, and third clutches on said main shaft for controlling said mechanisms respectively, first,'second, and third control mechanisms including first, second, and third control levers pivoted on said carriage engaging said control rail and so spaced that each mechanism starts and stops at substantially the ends of the hearth, and first and second stop devices operated by said first and second control mechanisms for stopping said poker and shovel respectively out of the fire.

'7. In apparatus for lead smelting, a hearth having a long narrow trough and apron, means for poking the charge and leveling it down, throwing part on the apron, means for scraping the part on said apron, means for imparting a sudden fiip to said part of the charge to throw said part against the back of the trough, so that the particles roll forward with a selective action forming said charge into a bank, and means for feeding a layer of premixed fuel and ore into the trough.

8. Metallurgical apparatus comprising a hearth having a trough, a carriage, means for moving said carriage back and forth along said hearth, a rabble shaft on said carriage, a crank on said rabble shaft, a rest on said carriage near said trough, a poker on said rest and pivoted to said rabble shaft, a shovel rod having a shovel on the end thereof, means for operating said shovel rod including a shovel shaft, said shovel shaft and rabble shaft being spaced along said hearth and at about the same level, a main driving shaft and means including separate clutches for connecting said main shaft and shovel and poker shafts respectively HUGH R. MACMICHAEL.

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