US2119425A - Charging machine for open hearth furnaces and the like - Google Patents

Description

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P. H. DOUGLAS El AL Filed Aug. 20, 1935 CHARGING MACHINE FOR OPEN HEARTH FURNACES AND THE LIKE hm mm kl nn m May 31, 1938.

P. H. DOUGLAS ET AL CHARGING MACHINE FOR OPEN HEARTH FURNACES AND THE LIKE Filed Aug. 20, 1935 7 Sheets-Sheet 2 M 31, 1938. DUGLAS |-:-r AL 2,119,425v P H m I CHARGING MACHINE FOR OPI EN HEARTH FURNACES AND THE LIKE Filed Aug. 20, 1935 7 Sheets-Sheet 5 INVENTORS. Baa/L h. DOUGLAS BY JbH/v Ffioams y 1938- P. H. DOUGLAS ET AL 2,119,425

CHARGING MACHINE FOR OPEN HEARTH FURNACES AND THE LIKE Filed Aug. 20. 1935 7 Sheets$heet 4 IN VENTORS.

'7 sheets-sheet 5 IDAUL H. Douams 5 wk m 6 0 WN 0 W ww h m w M v Q \8 E W A wh w L" E 1 b w A W gm W W w fl fl w 1 WMHMWH Ma A fi islulil wfi zfiu: 2 MW WW h m NR zmlr MN \m \m May 31, 1938. P. H. DOUGLAS ET AL CHARGING MACHINE FOR OPEN HEARTH FURNACES AND THE LIKE Filed Aug. 20, 1935 7 Sheets-Sheet 6 Filed Aug. 20, 1955 nm i im WK W. m? m E Ro G QR Q h n;

HF. M 7% May 31, 1938. P. H. DOUGLAS El AL CHARGING MACHINE FOR OFEN HEARTH FURNACES AND THE LIKE Filed Aug. 20, 1935 7 Sheets-Sheet '7 m? m A J/LLF N Patented May 31, 1938 PATENT OFFICE CHARGING MACHINE FOR OPEN HEART'H- FURNACES AND THE LIKE Paul .H. Douglas and John F. Rogers, Cleveland Heights, Ohio, assignors to The Wellman Engineering Company, Cleveland, Ohio, a corporation of Ohio Application August 20, 1935, Serial No. 36,990

26 Claims.

This invention relates to a machine for charging furnaces, particularly open hearth furnaces, and it is especially adapted for use in carrying out the furnace charging process described and claimed in our application Serial No. 27,779 filed June 21, 1935, for Method of charging furnaces,

in'which the present charging machine was illustrated in part and described. In our prior application we have describeda cold metal charging process the purpose of which is to depart from the spoonful method heretofore used in charging open hearth furnaces and to handle the cold metal charges in relatively large bulk. According to said process, a large part and preferably the entire cold metal charge required for the melting heat is deposited in the furnace at one time, thereby affording a more economical process as to power and fuel'consumption, speed of operation and maintenance cost of the charging equipment and furnace.

The principal object of the present invention is to provide a charging equipment adaptable for carrying out the process of our prior application in a successful and eflicient manner.

More particularly it is the aim of the present invention to provide entirely novel cold metal charging equipment which eliminates the use of the present small charging box with its transporting apparatus and the present charging machine and which utilizes instead a container of .ample capacity to handle at one time the entire or at least a large part of the cold metal charge.

A further object is to provide a charging machine of simple design and few motions which, with certain modifications in the structure at the front of the furnace and the provision of an appropriately large door or removable furnace front enables the cold.metal charge to be deposited over the entire furnace hearth by progressively depositing it thereon in a layer of approximately uniform thickness.

The charging equipment of the present application includes a receptacle or pan with a flexible rolling bottom having a floor or bottom area comparable with that part of the hearth area whichis to be charged and preferably equal substan the layer on the hearth approximates the thickness and area of the layer on-the pan.

. The second main unit of the charging equipment includes the charging machine proper which is adapted to run back and forth along the front of the battery of furnaces and is constructed and adapted to receive the loaded pan, to convey it to the furnace to be charged, and, after the furnace front has been removed, to run the pan into the furnace and to transfer the charge onto the hearth in the manner stated above.

The invention may be further briefl summarized as consisting in certain combinations and arrangements of parts and details of construction which will be described in the specification and set forth in the appended claims.

Referringnow to the drawings:-

Fig. 1 is a plan view showing conventionally or diagrammatically a series of open hearth furnaces, the charging equipment, and a part of the scrap storage yard where the pan is loaded with cold metal, which usually consists of scrap metal, and from which it is conveyed over a yard track to an elevator or hoist mechanism by which the loaded pan is elevated to a suitable height to be received on the cradle of the charging ma chine proper, the furnaces being shown in section;

Fig. 2 is a view in elevation with the loaded Dan in section showing the pan elevated from the level of the yard ready to be received on the cradle;

Fig. 3 is an elevation with parts in section showing the loaded charging machine in front of the furnace to be charged;

Fig. 4 is a similar view showing the charging equipment at about the middle of the charging operation, 1. e., when the layer of cold metal on the pan is being transferred onto the furnace hearth;

Fig. 5 is a longitudinal vertical sectional view of the pan;

Fig. 6 is a similar view on an enlarged scale showing the position of the flexible pan bottom during the charging operation, this view showing how the pan bottom rolls under the pan frame and therefore drops away from the metal supported on the pan so that the metal will be deposited in a substantially uniform layer on the furnace hearth during the charging operation;

Fig. 7 is a sectional view through the charging pan substantially along the line 11 of Fig. 6 i

Fig. 8 is a plan view of the pan;

Fig. 9 is a view looking at the rear side of the' pan showing by dotted lines the carrying fingers of the cradle of the charging machine;

ment into the furnace; Fig. 17 is a view showing- Fig. 10 is a plan view of the charging machine, this view showing the cradle in its fully retracted position;

Fig. 11 is a view looking at the front side of the charging machine, i. e., toward the furnace or the side adjacent the bottom of Fig. 10;

Fig. 12 is an end view of the charging machine showing the cradle fully retracted as in the plan view of Fig. 10; I

Fig. 13 is a transverse sectional view substantially along the irregular line i3i3 of Fig. 10, the pan being shown by dotted lines on the cradle:

Figs. 14 'to 23 inclusive are views which illus-' trate particularly certain automatically actuated parts which control the charging of the furnace, i. e., the rolling of the flexible pan bottom under the pan fi'ame when the cradle is being retracted from the furnace and the restoration of the pan bottom to its normal position on the frame during the latter part of the return movement of the cradle. Fig. 14 shows the cradle fully retracted and the positions of the parts which control the actuation of the pan bottom when the cradle is in the position stated; Fig. 15 shows the rear end of the cradleand the position of the so-called charging pawl just before the completion of the movement of the cradle into the furnace;' Fig. 16 shows the pan and cradle at the completion of the inward or forward movea part of the cradle just before the completion of the charging operation; Fig. 18 shows the cradle and pan at the completion of the charging operation; Fig. 19 shows the charging pawl in the position that it occupies when the cradle is vin the position indicated in Fig. 15; Fig. 20 is asimilar view showing the pawl moved to charging position or in the position which it occupies during the movement of the cradle from the position shown in Fig. 16 to the position shown in Fig. 1'1; Fig. 21 is a similar view showing the pawl mechanism near the end of the charging operation, this view showing the position of the pawl mechanism just before the beginning of the return movement of the pan bottom to normal position as shown in Fig. 17; Fig. 22 is a plan view of the pawl mechanism shown in the preceding views and its supporting fra-m and Fig. 23 is a sectional view through .one of the beams of the cradle showing the position of the pawl mechanism of Fig. 22 with reference thereto;

Fig. 24 is a sectional view substantially along the irregular line 24-24 of Fig. 10; and

Fig. 25 is a sectional view taken along the line 2625.of Fi 10.

Referring now to the drawings and first toqthe diagrammatic views of Figs. 1 to 4, we have shown at 25 a battery of open hearth furnaces of which there may be any number. These furnaces may be of usual construction except that,

with the charging machine of the present application which contemplates supplying the entire cold metal charge of the furnace or a layer over the entire hearth in one charging operation and which progressively deposits the layer more or less uniformly over the furnace hearth, there is required a charging opening.25a equal substantially to the length of the hearth 25b. For closing the long opening 26a at the front of the furnace we prefer to employ a movable furnace front 25c which is shown in closed position in Fig. 3 and in open position in Fig. 4. The furnace with this long movable front or front wall and the mechanism for moving the latter to and from closed position constitute the subject matter of a companion application Serial No.

machine proper constituting one unit, and a suitable receptacle for the cold metal charge which, for convenience, will be referred to as the pan constituting the second unit. The pan may be filled at any suitable point with cold v metal and brought up to and deposited on the cradle of the charging machine which can then be moved along the track 26 in front of the furnace 25 to be charged, and, after the charging operation is completed, the empty pan may be removed from the cradle and again filled with cold metal.

In general, the charging machine proper includes a chassis or wheeled frame 21 which trav-- els along the track 26 and is provided with'a transversely movable carriage or platform 29 provided at the front with a cradle 29 for receiving the pan 39 adapted to receive the cold metal which is designated 3| in Fig. 2, both the pan and the cold metal being here shown in transverse vertical section. In 4 the cold metal charge 3i is being deposited on the hearth 26b of one of the furnaces, this view showing about the middle of the charging operation. Generally the cold metal charge consists of scrap metal which isfusually piled in a yard designated 32 in Fig. -1 located more or less close to the battery of furnaces. In this instance, one or more tracks 33 extend through the scrap yard 32, and the pan 3| is'adapted to be conveyed to the scrap pile on a transfer car 34 designed to travel along the tracks 33. The scrap can be conveniently loaded onto the pan by a magnet carried by a trolley 35 movable upon the bridge of a crane 36 adapted to travel along a crane trackway 31. All this apparatus, including the elevator to be referred to, is shown diagrammatically in Fig. 1.

Usually the scrap yard is below the level of the charging floor, in which event we provide adjacent the first furnace 26 and also adjacent the trackway .26 for the charging machine an elevator indicated diagrammatically at 38 in chine. In this instance it is contemplated that when the pan is elevated to the position shown in Fig. 2 the cradle be run forwardly under the a pan or rather into the. pan frame to be referred to presently, after which, by lowering the blocks 39, the pan will then rest upon the cradle, whereupon the blocks will be detached, the eradle will again be retracted so as to clear the furnaces, and the charging machine will then be moved along the track 26 so as to position the pan directly in front of the furnace to be charged, as shown in Fig. 1.

It might be mentioned at this pointthat with the present charging equipment after the charging machine is in the full line position of Fig. 1, i. e., in front of one of the furnaces, the cradle and loaded pan will run forwardly until the front edge of the pan is near the rear side of the hearth. Then the cradle is retracted, and, whilebeing retracted, the bottom of the pan, which is flexible and preferably of the apron conveyor .type, is run .be seen by reference to Fig. 1.

underneath the pan frame in the manner to be explained so as to deposit the cold metal layer progressively and uniformly over the hearth and, after the charge is deposited on the hearth and while the cradle is still being retracted, the flexible bottom or apron is again run back on top of the pan frame or to normal position, the restoration of the pan bottom to normal position being completed just before the completion of the retraction of the cradle to itsfull backward position indicated in Figs. 1 and 3. Since in this instance (though not necessarily) the entire cold metal charge required for the melting heat is deposited in the furnace at one time and is laid over substantially the entire hearth, the area and length and width dimensions of the pan are equal substantially to the area and corresponding dimensions of the hearth and the width of the charging machine (measured lengthwise of the furnace and of the charging machine track 26), including of course the width of the pan, is equal substantially to the length of the hearth, as will Obviously, since the hearth of the commonly employed open hearth furnace is of considerable length, 45 feet more or less, and has a very large capacity, 150 tons of metal more or less, the charging machine of our invention differs radically in size, capacity, and structure, as well as in mode of operation, from the charging machines heretofore used. The capacity and length of the hearth and the dimensions and capacity of the charging machine are not mentioned in any limiting sense but to better emphasize the capabilities of our charging equipment and the radical departure from the standard practices in charging open hearth furnaces.

We will now describe the construction of the charging machine and of the charging pan, reference being first had to Figs. to 9. The charging pan is provided with a rigid structural framework consisting in this instance of a front beam 40, a rear beam 4|, both extending the full width of the pan, and a series of cross beams 42 spaced a uniform distance apart and extending from the front to the rear of the frame. This frame has fixed upstanding end walls 43 and carries a movable flexible pan floor 44 having a back wall 45 composed of a supporting frame and a solid preferably inclined plate the height of which is equal substantially to the height of the end walls 43, it being understood that when the pan floor is in its normal position shown in Fig. 5 the back wall is at the rear of the pan and that this back wall along with the end walls holds the cold metal charge on the pan bottom when the loaded pan is being moved to and with the charging machine. I

The floor 44 is of the apron conveyor type and is made up of overlapping plates 44 of suitable width to provide the necessary flexibility, and they may extend the full width of the pan but preferably less than the full width. That is to say, although the flexible floor extends the full width of the pan, the overlapping plates 44, for convenience of manufacture and replacement, are preferably in convenient lengths arranged end to end. These overlapping floor plates are linked together and are carried by rollers 46 which, as clearly shown in Figs. 5, 6, and '7, are arranged to operate on the top flanges of the beams 42,

endless chain so arranged that as the plates of the pan floor ro ll forward on the top flanges of the beams 42 and over the front end around the curved guide tracks 41, the tail -chains 48 pullthem back onto the lower tracks formed by the tops of the lower flanges of the beams 42.

The frame of the back wall 45 is provided with suitably located pockets 50 (see Fig. 6) for automatic connection with the coupling lugs of the pan floor operating or charging bars on the charging machine as the pan is lowered onto the cradle of the charging machine. As many of these pockets 50 as there are charging bars will be employed, two being preferably utilized, these charging bars serving to hold the rear end of the pan floor stationary so that the pan floor will roll around the front and underneath the pan frame while the cradle is being retracted during the charging operation, as will be described more fully later.

Referring now to the construction of the charging machine proper, this charging machine is provided with a main frame which is preferably made in two or more sections, two being preferred, connected together at the middle by couplings 5| (see Figs. 10 and 11) to insure proper loading on all track wheels, but may be made in one piece with other means of equalizing the wheel loads. Each section of the main frame is built up of structural members consisting in this instance of a series of longitudinal beams 52 and a series of cross beams 53 extending from the rear to the front of the frame transversely of the track 26 upon which the charging machine runs. The rear side of the main frame may be provided with a suitable counterweight indicated at 54 in Figs. 12 and 18 to provide the necessary stability when the cradle and pan are in their extremev forward positions, and means, not shown, may be provided to accommodate an operator's platform at any convenient place on the machine frame or on the movable platform if preferred.

The main frame is mounted on the track wheels 55, four of which are provided on each section of the frame. The charging machine is propelled along the track 26 by two synchronized motors 56 mounted on extensions at the ends of the frame and connected by reduction gearing 51 to shafts 58 (Fig. 10) which in turn are geared to the track wheels at the four corners of the frame. These motors, as well as the motors which operate the platform'and cradle, will be equipped with solenoid or other suitable automatic brakes, and the gearing will be housed and run in oil, but details of this character do not, of course, constitute essential features of the invention.

Mounted on the main frame to travel forwardly and rearwardly thereof is a. platform consisting preferably of a series of parallel beams 59 uniformly spaced, as shown in Fig. IB, this platform being arranged to travel transversely across the frame on flanged rollers 60 carried by the main frame, upper rollers 6| toward the rear of the frame and forward upper rollers 62 toward the front of the frame engaging the upper flanges of the beams 59 to prevent tipping of the platform when loaded and run forwardly. At the forward ends of the beams 59 of the platform are fingers 63 forming the cradle which supports the pan, these fingers consisting of beams which extend forwardly from the beams 59 of the platform and pockets 84 in which the cradle beams are inserted forconvenience in replacement. The panisadapted'to rest directly on the-cradle beam 88, and suitable abutments or guides, indicated at 68a in Fig.

,12, hold the pan against accidental displacement at all times. When the pan is lowered onto the cradle by the hoist mechanism illustrated in Fig. 2, the front end of the cradle beams or fingers 63 are preferably extended underneath the top flange of the beam 40 extending across the front of the pan in the manner illustrated in Fig. 13 and the rear end of the pan is then lowered into place.

The platform and the cradle are moved on the supporting rollers 68 by racks 85 secured to the top flanges of the main cradle beams 58 and meshing with driving pinions 66 mounted on a cross shaft 81 (see Figs. 10 and 25) driven through gear reduction units 68 located at the opposite ends of the shaft 61 by two synchronized electric motors 68 supported at the opposite sides of the machine in the manner indicated in Figs. 10 and 11. The main pinion shaft 81 is preferably made in two sections arranged end to end and connected together at the middle by a suitable flexible'coupling 10 (Figs. 10 and 11) to compensate for any misalignment due to'the split main frame. This shaft is carried by bearings provided on an upper framework H supported by brackets 12 on the main frame. The upper forward rollers 82 are mounted to turn freely on the drive shaft 61 whereas the rear set of upper rollers 8| is mounted in a similar upper framework 18 supported by brackets 12 on the main frame. The framework II for thedrive shaft 81 and for the rollers mounted thereon and the framework 18 for the rear set of rollers 8| as well as the supporting brackets 12 are illustrated in Figs. 10 to 13, 24 and 25.

It is to be noted that the platform beams including the extensions forming the cradle are independently supported as is desired to provide flexibility. However, they are maintained in their proper relative positions by the flanged supporting rollers and are moved back and forth simultaneously since the actuating pinions engage racks one of which is provided on each of the beams.

As already explained, to charge a furnace the cradle and the loaded pan are run into the furnace the full distance. Then the platform is retracted, and, whilebeing retracted, the pan floor is caused to roll underneath the pan frame, the rear wall of the pan then being held stationary and after the entire charge is deposited on the hearth and while'the platform and cradle are still being retracted, the pan floor is rolled back onto the upper side of the pan frame. These operations are performed automatically during the charging process preferably by two charging mechanism units which are automatically actuated by the movement of the platform and are located on opposite sides of and equidistant from the center of the platform so as to maintain the pan floor in proper alignment. These two charging mechanism units each include a pan floor operating or charging bar 14 arranged for forward and backward motion and supported on guide rollers 15 mounted on the adjacent platform beam 58. These two charging bars and their supporting rollers are clearly shown in Figs. 10, 13, 24, and 25, and one of them is also indicated by dotted lines in Fig. 6. Each charging bar has at its forward end an upstanding coupling lug 18 designed to automatically engage in one of the pockets 50 (Fig. 6) provided on the frame of the back wall" of the charging pan as the latter is lowered onto the cradle. Each charging bar is also provided at its rear end with a lug 'll. Additionally, each charging mechanism unit includes a pawl mechanism illustrated in Figs. 14

to 23 inclusive, and mounted in a frame 18 (Fig.

22) supported in fixed position on the main frame of the charging machine in the manner illustrated in Figs. 23 and 25, this pawl mechamsm being arranged adjacent one of the longitudinal beams 59 of the platform. Each of these pawl mechanisms includes a pawl 18 -(see particularly Figs. 19, 20, 21, and 25) adapted to engage with the lug I1 at the rear end of the charging bar I4, the pawl 19 being mounted on a rock shaft 88 Journaled in the pawl frame 18 and having fixed to it two arms 8| and 82. Arm 8| is connected by a link 88 to an arm 84 on a second rock shaft 85 also mounted in the pawl frame 18. The arm 8|, link 88, and arm 84 constitute a toggle mechanism held in locked position indicated in Fig. by a counterweight 8B flxed to the rock shaft 85 and provided with a roller 81. Another arm 88 which is also fixed to the rock shaft 85 carries a roller 89. Additionally, the rock shaft 85 has flxed to it an arm 90 connected by a link 9| to the arm 82 fixed to the rock shaft 80, as before stated.

When the charging machine is in front of the furnace to be chalged, with the platform fully retracted, the parts of each pawl mechanism are in the relative positions shown in Fig. 19 and remain in that position until the-cradle and the loaded pan are run into the furnace, and as the platform approaches its forwardmost position, i. e., as the loaded pan approaches the far side of form beam which is adjacent the pawl mecha-- nism comes into engagement with the roller 89, as indicated in Fig. 19, and during the remainder of the inward or forward movement of the platform, cradle, and pan, this lug 82 throws the pawl 19 upward to the position shown in Fig. 20 behind the lug 'I'l on the rear end of the associated charging bar I4. -When this occurs, the toggle formed by the link 83 and the arm 84 and the rock shaft is moved to locking position and the counterweight swings over the vertical center so that it holds the parts in the position just stated. Thus the pawl becomes in effect a rigid member resisting backward movement of the already described. After this charging operation is completed, with the platform now partly retracted, second lugs 93 on-the two platform beams 59 adjacent the two pawl mechanisms come in contact with the rollers 81, as indicated in Fig. 21, and continued rearward movement of the platform causes these lugs to throw the parts of the two pawl mechanisms to the position shown in Fig; 19, Fig. 21 showing the parts in the position when the lug 83 is in the act of moving the parts of each pawl mechanism from the position shown in Fig. 20 to the position shown in Fig. 19. Fig. 16 shows the parts at the start of the charging operatiom. Fig. 1'7 shows the parts when the The retraction of the platform, the cradle,

and the now empty pan continues, and while the platform is moving from the position shown in Fig. 18 to its rearmost position shown in Fig. 1d, the charging bars are moved backward at twice the speed of the backward movement of the platform, thus restoring the pan bottom to normal position or from the position shown in Fig. 18 to the position shown in Fig-14. This is done automatically by a pan fioor return mechanism also in two units associated with the two charging bars and with the two platform beams 59 adjacent thereto. Each of these two pan floor return units includes a shoe 94 arranged to slide on a, guide bar 95 mounted on the adjacent platform beam 59 (see Figs. 13 to 18 inclusive), and includes also two cables 96 and 91 the former fixed to one side of the shoe '94 and extending rearwardly around a sheave 98 mounted on the rear end of the adjacent platform beam 59 and anchored to the charging lug 11 at the rear end of the charging bar (see particularly Fig. 14,) and the second cable 91 extending from the opposite side of the shoe 94 forwardly around a second sheave 99 also mounted on the platform beam 59 and then rearwardly from the sheave 99 and anchored to the lug ll of the associated charging bar. Each of these units also includes a stop lug Hill (Figs. 14 to 18 and 23) supported in stationary position 'on the main frame of the charging machine in the path of the shoe 94.

Each of these pan floor return units, including the guide shoe 94, the guide bar 95,-the cables 96 and 91, the sheaves 98 and 99, and the stop lug 100, is associated with each of the charging bars 14, and the two return units act simultaneously on the two charging bars. The operation of these units to cause the return of the pan bottom to normal position is as follows: At the end of the charging operation the parts are as shown in Fig. 18, with the charging pawl 19 swung down away from the lug 11 at the rear end of the charging bar, the charging bar now being at its forwardmost position as shown in this figure and the sliding shoe 94 being at the end of the guide bar 95 against the stop lug I00. It will be remembered that the charge was deposited on the hearth by the retraction of the platform and the cradle from the position shown in Fig. 16 to the position shown in Fig. 18. Since the shoe 94 to which the two cables 96 and 91 are attached has come up against the stop lug I09, it is of necessity held stationary during the further retraction of the platform from the position shown in Fig. 18 to the position shown in Fig. 14, and consequently since the two sheaves 99 and 99 around which the two cables pass move back with the beam, and since the cables are connected to the rear end of the charging bar, the charging bar is moved backward at twice the rate of movement of the platform, and in so doing pulls the rear end of the pan backward, causing the pan floor to roll back onto the pan frame from the position shown in Fig. 18 to its normal position shown in Fig. 14.

The following is a brief description of the operation and functioning of the equipment described in detail above. The loaded pan on the transfer car is moved from the filling site to a position under a hoisting tower or the like. of course, it is not at all essential that the scrap yard be at a lower level than the charging floor,

but such is generally the case, as already stated.

The pan is then lifted from the transfer car and is deposited on the cradle of the charging machine which has previously been moved to a position to receive the pan, 1. e., in front of the tower if the latter is employed. The hoisting mechanism may be mounted on the trolley of a crane so as to carry the loaded pan laterally over the cradle after the pan is hoisted to the proper elevation, but in this instance the cradle is moved.

forward under the pan and the pan is lowered onto it. With the hoisting mechanism herein contemplated, the forward hoist blocks are connected to the back frame of the pan and the rear hoist blocks are connected to the ends of a hoist ing beam 390. (Fig. 2) forming a part of the hoisting mechanism. Then the platform of the charging machine is retracted, carrying with it the loaded pan, and the charging machine is moved along the trackway 26 until the same is brought directly in front of the furnace to be charged. In practice, the traveling motion of the machine may be stopped in any manner desired either through the usual operators manual control of the electric motors or through the agency of automatic selective switches to cause the machine to be stopped independently of the operator's will with the center of the charge directly in front of or coinciding with the center of the furnace. After the charging machine has come to a definite stop, the furnace front may be removed so that the furnace will receive the charge.

The pan is then moved into the furnace and the charge is deposited on the hearth. At this point it might be statedthat although we have shown one type of pan floor arid one way of transferring the charge from the pan onto the hearth, nevertheless, so far as the broad features of our invention are concerned, any means may be employed which will cause the charge to gradually leave the pan and form an evenly distributed layer on the hearth.

With the flexible floor bottom and the instrumentalities for operating it herein illustrated and described, as the cradle is moved forwardly the charging bars are of course carried forwardly with the loaded pan, and as the latter approaches its extreme forward position the setting lugs 92 on the cradle engage the rollers 89 of the charging pawl mechanisms and cause the pawls 19 to be moved up behind the lugs at the rear ends of the charging bars and are fixed in that position by the toggles and by the counterweights which hold the pawls and toggle parts in fixed relation. Then the cradle reverses its motion, moving backward and carrying the pan framework backward with it, but the charging bars 14 are held stationary by the pawls 19 so that as the pan frame is withdrawn from under thefiexible pan floor the floor rolls over the front end and is drawn back under the pan'frame, dropping away under the charge and depositing it uniformly over the furnace hearth until the back wall is at the front end of the pan and all material is charged into the furnace. During this backward motion of the platform and the cradle, the floor return sliding shoes 94 are moved backward at double the speed of the cradle by the action of the return cables 96. As the cradle approaches the end of the charging part of its backward travel, the release lugs 93 on the cradle engage the rollers 81 of thecounterweighted pawl release arms until the pawl locking toggles are released and the counterweights moved to a position to hold the pawls I! in the positions shown in Fig. 19. In this position of the cradle the pan fioor return sliding shoes 94 have reached their back positions on the cradle and engage the fixed stop lugs I" on the main frame. As the cradle continues its backward travel, the sliding shoes are held'stationary by the lugs IIIO and as the return cable sheaves 98 and 99 move backward with the cradle, the cables pull the charging bars H and the pan floor backward at double the speed of the cradle until the cradle and the platform have reached their extreme rear position on .the charging machine and until the pan floor and the back wall of the pan have returned to their original normal positions.

The cycle of operations now having been completed, the empty pan may be again transferred to the hoisting mechanism, lowered onto the transfer car, and refilled for charging another furnace.

It will be understood, of course, that more than one pan may be employed with a single charging machine so that while one pan is on the charging machine another may be in the yard being filled. In this connection it might be stated that the loaded and empty pans may be transferred to and from the cradle and handled in the yards in any desired manner, and the particular means herein illustrated is not at all essential to the successful and economical use of our charging machine. Likewise, various otherparts of the machine and of the pan may be constructed in other ways than herein illustrated, and we therefore do not desire to be confined to the precise details or arrangements illustrated but aim in our claims to cover all modifications which do not involve a departure from the spirit and scope of the invention in its broadest aspects.

Finally, we wish to state that the, present charging machine is adapted not only for transferring to the hearth of the furnace the cold metal charge but is preferably used also for spreading onto the hearth in advance of the cold metal chargea layer of limestone. The limestone may be added in a separate charging operation from that utilized in supplying the cold metal. We contemplate also with a slight modificatlon in the construction of the apron to apply the limestone charge and approximately one-half of the cold metal charge in one operation and the remainder of the cold metal charge in a second charging operation. Whether the cold metal is applied in one charging operation or in two charging operations, with the machine herein illustrated the cold metal will be deposited in each operation in a layer over substantially the entire hearth, and the same is true of the limestone charge. confined to depositing the entire cold metal charge or a portion thereof over the entire hearth at one time as we regard it within the purview of our invention to provide a charging machine of such dimensions with respect to the hearth that a portion of the hearth, say, one-half the hearth, would be covered with a layer of cold metal in substantially the manner herein described in one charging operation and another portion or the remainder of the hearth similarly charged in a second charging operation.

Having thus described our invention, we claim:

1. A charging machine for charging open hearth furnaces and the like comprising a substantially horizontally extendingwheeled frame adapted to be moved along a trackway in front of a furnace, and a platform movable over the However, we do not wish to beframe in a direction substantially normal to the direction of movement of said frame, said plat-- form including a plurality of parallel independently supported beams disposed in a substantially horizontal plane and being provided at the front with means for receiving and supporting a re-' ceptacle filled with the material to be charged into the furnace.

2. A charging machine for open hearth furnaces and the like comprising a wheeled frame having a platform with a cradle for receiving and supporting a receptacle containing material to be charged into the furnace, said platform being composed of a plurality of parallel substantially horizontally disposed independently supported and independently driven beams.

3. A charging machine for open hearth furnaces and the like comprising a movable sectional substantially horizontal mainframe and a movable sectional substantially horizontal platform on the main frame provided at the front with means for receiving and supporting a receptacle for the material to be charged into the furnace, the sections of both the main frame and the platform being relatively movable so as to provide flexibility.

4. A charging machine for open hearth furnaces and the like comprising a substantially horizontal sectional main frame movable along in front of one or more of such furnaces and a movable substantially horizontal sectional platform movable on the main frame in a direction substantially normal to the movement of the main frame and provided at the front with means for receiving and supporting a receptacle for the material to be charged into the furnace, said means for supporting the receptacle including a plurality of parallel forwardly projecting cradle beams, the sections of both the main frame and the platform being relatively movable so as to provide flexibility.

5. A unit of a charging equipment for open hearth furnaces including a pan composed of a frame having means whereby it may be removably supported on the cradle of a charging machine and provided with a flexible floor normally extending over the top of the frame and adapted to be rolled underneath the same.

6. A unit of a charging equipment for open hearth furnaces including a pan composed of a frame having means whereby it may be detachably supported on the cradle of a charging machine and provided with a flexible floor normally extending over the top of the frame'and adapted to be rolled underneath the same, the front of the floor being connected by flexible means to the rear thereof to form an-endlessmember.

'1. A furnace charging unit in the form of a receptacle adapted to receive material to be charged into a furnace in the form of a pan adapted to be removably supported on the cradle of a charging machine and composed of a frame with a flexible floor movable over the frame to the under side of the same and provided with an upstanding back wall movable therewith.

8. A unit of charging equipment for open hearth furnaces and the like in the form of a pan adapted to be removably supported by a charging machine, composed of a frame having upstanding end walls, a flexible floor movable forwardly and rearwardly between the end walls,

and a back wall movable with the frame, said frame having means for receiving a plurality of supporting fingers on the charging machine.

9. Charging equipment for open hearth furnaces and the like comprising a charging machine having a main frame movable along in front of one or more of such furnaces, a platform movable forwardly and rearwardly over the main frame along a. pathextending substantially nor-, mal to the direction of movement of said main frame, a pan adapted to be removably supported by the platform and having a frame and a flexible floor, and means operating automatically during movement of the platform along said path to cause the floor to be moved forwardly over the pan frame to the underside of the latter so as to discharge the material into the furnace and back over the pan frame to normal position.

10. Charging equipment for open hearth furnaces and the like consisting of a charging machine and a pan for the ,material to be, charged into the furnace, the charging machine comprising a wheeled frame'movable along in front of one or more of such furnaces and a platform movable thereover' along a path extending substantially normal to the direction of movement of said frame including means for supporting the pan, the pan having a frame and a flexible floor, and means operating to cause the floor to be moved forwardly over the pan frame to the under side thereof and back to normal position all during the movement of the platform in one direction.

11. Charging equipment for open hearth furnaces and the like comprising a charging machine having a main frame movable along in front of one or more of such furnaces and a platform movable over said frame along a path extending substantially normal to the direction of movement of the frame, a pan adapted to receive the material to be charged into the furnace and adapted to be supported by the plat form and to be moved into and out of the furnace, said pan comprising a frame and a flexible floor, and automatic means actuated during the retraction of the platform and the movement of the pan out of the furnace for causing the flexible floor to be moved forwardly to the under side of the pan frame so as to deposit the material thereon onto the hearth or floor of the furnace.

12. Charging equipment for open hearth furnaces and the like comprising a charging machine having a substantially horizontal main frame movable along in front of one or more such furnaces and a substantially horizontal platform movable over said frame along a path extending substantially normal to the direction of movement of the frame, a pan adapted to receive the material to be charged into the furnace and adapted to be supported by the platform and to be moved into and out of the furnace, said pan comprising a frame and a flexible floor, and automatic means actuated during the retraction of the platform and the movement of the pan out of the furnace for causing the flex- 14. In furnace charging apparatus, a pan adapted to be introduced into the furnace for depositing a charge therein comprising a frame having spaced beams provided with upper and lower flanges, a flexible floor adapted to travel along the upper flanges of the beams and around the ends thereof onto the lower flanges, and curved means engaged by the flexible floor in passing around the ends of the beams.

15. In furnace charging apparatus, a pan adapted to be introduced into the furnace for depositing a charge therein comprising 'a frame having spaced longitudinal beams and transverse beams adjacent the front and rear edges, the rear transverse beam being above thelongitudinal beams and the front transverse beamv being substantially in the plane of the longitudinal beams, and a flexible floor adapted to travel over the longitudinal beams and around the front transverse beam to the underside of the frame.

16. In furnace charging apparatus, a pan comprising a frame having spaced longitudinal beams and flexible floor adapted to travel along said beams, and a movable pan support comprising beams extending beneath the pan between the longitudinal beams thereof.

17. In furnace charging apparatus, a pan comprising a frame and a flexible floor, said frame having spaced longitudinal beams and a transverse beam disposed adjacent the front edge of the pan and substantially in the plane of the longitudinal beams, said floor being adapted to travel along the longitudinal beams and around the transverse beam to the underside of the pan, and a movable pan support comprising beams extending between the longitudinal beams of said frame and engageable with said transverse beam.

18. In furnace charging apparatus, a pan comprising a frame and a flexible floor adapted to travel thereon, said frame having spaced longitudinal beams and spaced transverse beams, one of the latter beams being substantially in the plane of the longitudinal beams and another crossing above the longitudinal beams, and a movable pan support comprising beams extending between said longitudinal beams and beneath said crossing transverse beam.

19. In furnace charging apparatus, a pan comprising a frame and a flexible floor adapted to travel thereon, said frame having adjacent the front of the pan a transverse beam with a rearwardly extending top flange, and a movbeam being substantially in the plane of the longitudinal beams and having a rearwardly extending top flange, and a movable pan support comprising spaced members extending forwardly between the longitudinal beams and en-' gaging under said flange of the front transverse beam.

21. A charging machine for charging open hearth furnaces and the like comprising a frame movable along in front of one or more such furnaces, a platform movable over said frame toward and from the furnace to be charged and having at the forward part thereof a generally flat substantially horizontal support, a pan adapted to rest on said support and having a flexible floor movable to the under side of the pan for discharging material therefrom, means for holding one edge of said floor relatively stationary, and means for moving said platform over the frame to cause the floor to travel to the underside of the pan.

22. A charging machine for charging :open hearth furnaces and the like comprising a frame, a platform movable over said frame toward and from the furnace to be charged and having at the forward partthereof a generally flat support, a pan adapted to rest on said support and having a flexible floor movable to the under side of the pan for discharging material therefrom,

means engageablewith one edge of said floor and movable relative to the platform, means for moving the platform over said frame, and means on said frame cooperating with said engageable means to prevent movement thereof during a portion of the travel of said platform to thereby cause the floor to travel to the underside of the pan.

23. In .apparatus for charging open hearth furnaces and the like, a frame, a platform movable over said frame and adapted to be inserted into a furnace opening, a pan adapted to be received on said platform and having a flexible floor movable to the underside of the pan for discharging material therefrom, means for moving said platform over the frame to insert said pan into the furnace and withdraw the same therefrom, and means rendered effective upon a predetermined extent of such movement of the platform, for holding one edge of said flexible floor relatively stationary whereby succeeding movement of said'platform causes the floor of the pan to travel to the underside thereof.

24. In apparatus for charging open hearth furnaces and the like, a frame, a platform movable over said frame and adapted to be inserted into a furnace opening, a pan adapted to be received on said platform and having a flexible floor movable to the underside of the pan for discharging material therefrom, means for moving said platform over the frame to insert said pan into the furnace and withdraw the same therefrom, means on said platform adapted for holding engagement with one edge of said pan floor, such holding means and said platform being relatively movable to cause said floor to travel to the underside of the pan, and mechanism on said frame for maintaining said holding means relatively stationary during a portion of the travel of said platform.

25. In apparatus for charging open hearth furnaces and the like, a frame,a platform movable over said frame and adapted to be inserted into a furnace opening, a pan adapted to be received on said platform and having a flexible floor movable to the underside of the pan for discharging material therefrom, means for moving said platform over the frame to insert said pan into the furnace and withdraw the same therefrom, means on said platform adapted for holding engagement with one edge of said pan floor, such holding means and said platform be-' ing relatively movable to cause said floor to travel to the underside of the pan, means on said frame movable into position for maintain ing said holding means relatively stationary during a portion of the travel of said platform, and means on the platform for automatically shifting the last mentioned means into and out of I such position.

26. In apparatus for charging open hearth furnaces and the like, a frame, a platform movable over said frame and adapted to be inserted into a furnace opening, a pan adapted to be received on said platform and having a flexible floor movable to the underside of the pan for discharging material therefrom, means for moving said platform over the frame to insert said pan into the furnace and withdraw the same therefrom, means on said platform adapted for holding engagement with one edge of said pan floor, such holding means and said platform being relatively movable to cause said floor to travel to the underside of the pan, abutment means on the frame shiftable into and out of the path of travel of said holding means, and spaced members on said platform for shifting said abutment means, one of said members being adapted to shift said abutment meansv into operative position behind said holding means during movement of said platform toward the furnace and the other being adapted to shift the abutment means to inoperative position during movement of said platform away from the furnace and after actuation of said flexible floor.

PAUL H. DOUGLAS. JOHN F. ROGERS.

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