|Publication number||US2391173 A|
|Publication date||Dec 18, 1945|
|Filing date||Aug 21, 1943|
|Priority date||Aug 21, 1943|
|Publication number||US 2391173 A, US 2391173A, US-A-2391173, US2391173 A, US2391173A|
|Inventors||Loftus Fred H, Troglione Vincent R|
|Original Assignee||Loftus Engineering Corp Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (8), Classifications (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Dec. 18, 1945. F, LOFTUS ETAL CAR-BOTTOM FURNACE Filed Aug. 21, 1943 2 Sheets-Sheet 2 lNVENTORS firm It arrus Mme-Mr R. Tnoauquz BY Patented Dec. 18, 1945 NI TED ,STAT ES PATE N T FF 1 CE CAR-BGTTOM FURNACE Fred H. Loftus, Mount Lebanon, :and Vincent :R.
Tro-glione, Wilkinsburg, Pa.; said Troglioneas- Signor to Loftus Engineering Corporation, Inc, 7
Pittsburgh, Pa e. corporation of Delaware Application August-21, 1943, Serial *No. 499,466 .2 Claims. (01.104-165) Bur invention relates to industrial furnaces for heating, orannealing, or heat treating metal castings, or other articles formed of other materials. The invention isparticu'larly, though not exclusively, designed for oar-bottom furnaces, and in such association it will be described.
A furnace of the sort in mind comprises a furnace chamber constructed of refractory brickwork, externally rein-forced and tied by means of structural steel and tie-rods. The "floor portion of the furnace, upon which the articles to be heated are borne, comprises the body of a car-- a car that may be likened to a railroad fiat-car, whose floor is constructed of refractory blocks.
.car is adapted to travel on wheels or rollers between service position within the furnace, and loading and unloading position externally thereof. The front wall of the 'furnace is provided with a door which is opened and .closed, as :need be, to permit of the said movement of the car into and out of the furnace, and, when the furnace contains its charge, thedoor issealed shut.
In normal operation of the furnace, fuel and air are projected in regulatod "quantities "into the furnaceichamber, maintaining combustion therein and heating to desired temperaturethe-articles to heztreated. The products of combustion fined escape through suitable outgo ports that open through the walls of the i urnace chamber and communicate through suitable fiues to a stack or other vent. After the work has "been heated at regulated rate to the required temperature, the combustion 'within the furnace is retarded or interrnpted'and the work allowed to-cool through a specified cooling cycle.
.As indicated above, the upper surface of the car body provides the work-bearing floor .portionzofathe furnace-chamber. Means are provided for sealing the car body along its two sides and inner orlback end 5120 the two side walls and back wail cfithe ifurnace chamber, while the door of the furnace is sealed to the front wall of the furnace -.chamber :and to the outer or front :end of the car body. illhe art is "familiar with the structure andiorganization of sand seals for this purpose. As organized within the closed furnace, the dandy .of the :car'is in effect 'integrally united with theiurnace walls,2pro.viding.a furnace-chamherrin which the desired conditionsof combustion and thermal head may .be established and main tained.
In order to facilitate the loading :and unloading of :the furnace charge, the car that; :forms the worlebearing floor of the furnace .is moved in linear path out of the furnace chamber, into a position where the work is accessible to an-overhead crane, or other work-handling equipment.
Various mechanisms have been proposed and used for moving the car between said position of service within the furnace and said loading and unloading position externally thereof, and it will be understood that our invention is directed to new and useful improvements in such mechanisms.
One type of car-shifting mechanism hitherto in use consists in a cable anchored at one end to the front end-of the car and extending therefrom to a sheave spaced from the front of the furnace by an interval exceeding the length of the car. The outer end of the cable, trained over said sheave, is oonnected'to a crane, which, by pulling the cable, draws the car out of the furnace. In order to move the oar back into the furnace, one end of a second cable is .anchored to the inner end of the car, whence it extends over a sheave journaled beneath the car at the inner end of the furnace, .and from :such sheave extends the length of the furnace to another sheave that is spaced from :the front of the furnace, after the manner of the first-memtioned sheave. The crane is connected to ithe outer end of this second cable, and tension applied to the cable is effective toipull the'car into the furnace. In-a :more elaborate form of this mechanism, the sheaves spaced from the front'of the furnace arereplaced'bya motor-driven drum, upon which the otherwise free ends of'theicables are wound, one cable being wound in opposite .direction to theothenwherebyby rotating the drum one cable is paid out, :and .an equal length .of 113116 other rolled in, :effecting the travel .of z'the car. Rotation of :the drum in .one direction moves the car outward from :the :furnace, and :rotation in opposite direction moves the [car inward into the furnace. While a .mechanism.of thislsortxis effective :in its intended capacity, it is open to certain objections, among :which may ;-be noted: The sheave and cable within the furnace are exposed (particularly when the .car .-is withdrawn from the furnace") to the harmful effect .of the heat :developed within Ethe furnace and radiated from the hot furnace walls. Additionally, the floorspace in lfrontzof :the furnace is obstructed, obviously an objectionablecircumstance.
Another car-shifting unechanism comprises :a toothed :rack secured upon the :bottom of the car and extending longitudinally thereof. At the front of the iurnaoe .a .gear-apinion meshes with the teeth of such rack andamotor'is conengaged by the gear-pinion, whereby rotation of the furnace, and is is the pinion is adapted to shift the car outward a greater distance than the length of the car body that forms the work-bearing floor'of the furnace, with the effect that the work-bearing floor is moved clear of the furnace for accessibility to a crane or other car-loading and unloading ap paratus. anism is that the floor space immediately in front of the furnace is obstructed by the outward extending rack when the furnace is in normal operation.
The mechanism of our invention avoids objections of the nature indicated, and affords many advantages which will be apparent to those skilled in the art. A mechanism embodying the invention is illustrated in the accompanying drawings, in which:
- Fig. I is a fragmentary view in plan of the floor of a mill in front of a car-bottom furnace (not shown) with which the mechanism is organized. The mechanism is installed in a. pit in the mill floor, and appears in plan;
Fig. II is a view of the mechanism in side elevation, the pit and the floor of the mill, together with the front end of the car-bottom furnace, being shown in vertical section. on the plane 11-11 of Fig. I;
Fig. III is a wiring diagram;
, Fig. IVis a diagrammatic view, illustrating a modification in the structural organization of the mechanism, and Fig. Y is a fragmentary view, showing in side elevation and to larger scale a portion of the 'underframe or chassis of the car, and indicating the manner in, which a certain roller chain is secured to the frame; and
Fig. VI is a view in bottom plan of the structure shown in Fig. V.
Referring to the drawings, the reference nu- 'meral 2 indicates the car (fragmentarily shown in Fig. II) which forms the work-bearing floor of the furnace 3. The front end of the furnace is provided with a'doorway that is normally closed .by a door 4. The door is provided at its lower edge with blades that nest in a sand seal 6 at the front or outer end of the car. In order to load and unload the work or furnace charge, the door 4 is raised into open position, and the car is moved outward through the furnace doorway to a position where the car is entirely removed from the furnace. The car is in this case adapted to move on rails I, the car being equipped with railway wheels 8.
The mechanism for shifting the car 2 between its alternate positions comprises a plurality of wheels spaced apart in the linear direction of travel of the car. The wheels are connected to means for powerfully rotating them, and the'car is provided with means that engage the wheels in such manner that as the wheels are rotated the car is caused to travel. As shown in Figs. I and II, the pluralityof wheels comprises two toothed wheels 9 and H). The two wheels are journaled in a pit ll formed inthe floor I2 in front of the The objection to this car shifting mech furnace. The wheel-engaging means comprise a rack l3 mounted beneath and secured to the frame ll of the car. The rack l3 extends from one end of the car to the other and on the longitudinal center-line thereof, and the teeth of the wheels engage the rack.
An electric motor I5 is connected through a gear-box l6 and a chain-drive IT to rotate the shaft on which toothed wheel 9 is mounted, and a chain-drive l8 interconnects the shaft of wheel 9 with the shaft of wheel I 0, so that the two wheels 9 and I9 when rotated will rotate in unison. A weighted roller I9 is arranged to keep slack out of the chain l8. The energizing circuit 25 (Fig. III) of motor includes a controller 26 that is subject to push-button switches 21 and 28 and contact arms 23 and 24 of a limit switch 20. The limit switch 'includes a screw 22 connected by a chain-drive 29 (Figs. I and II) to the driveshaft of toothed wheel l0, A finger 2| engages the screw 22 as a nut, and as the screw is rotated the finger is caused to travel therealong.
When the car is tobe withdrawn from the furnace, the furnace door- 4 is opened and the pushbutton 21 is pressed, closing acircuit 30 through the then closed contact arm 23'of limit switch 20; the closing of such circuit operates the controller 26 which closes the circuit'25and sets the motor in rotation, rotating the wheels 9 and [9 counterclockwise (Fig. 11) and, by reason of the existing engagement of the wheel 9 with the rack I3,
the car moves outward from the furnace. 'As the car moves outward from the furnace, the rack l3 advances into engagement with the toothed wheel [9 that is rotating in unison with wheel 9, and
thus it is that the car may be moved beyond the.
position where the remote end (right-hand end) of the rack is engaged by the wheel ,9. The wheel 19 may be said to pick-up where the wheel 9 leaves off. The car is moved through a, distance equal to the length of the rack passing through engagement with wheel 9, plus the distance be-v tween the wheels 9 and [0, plus the length of the rack that passes through engagement with the wheel). The broken lines 2a in Fig. II indicate the position of the rear end of the car in its outermost position. i
- r The switch 21, oncepressed, remains in circuit closing position and the controller 26 holds the circuit 25 closed until the car reaches fully withdrawn position, whereupon the finger 2|, travelling in right-to-left direction (Fig. III) under the effect of the rotating screw 22, engages and swings the contact arm 23 into open position, thereby opening circuit and effecting; opera tion of controller 26 to de-energize the motor IS. The motor l5 immediately comes to rest, with the car fully withdrawn from the furnace.
When the car is to'be returned to'service position in the furnace, the push-button 28 is pressed, closing circuit 3i, through contact arm 24, which during the preceding right-to-left travel of the finger 2| moved into circuit-closing position. Thereupon, the controller 26 effects the energization of the motor 15 in alternate direction and the wheels 9 and [9 are driven in clockwise direction, moving the car into the furnace. As the car reaches full lentered position in the furnace, the finger 2|, then traveling in left-to-right di-' rection engages and swings contact arm 24 into open position. All movement of the mechanism is immediately arrested, with the car in proper position within the furnace. I
From the foregoing description, it will be understood that the interval between the wheels 9 and I is less than the length of the rack I3, and it is by virtue of this feature that the wheel 9 may be located substantially beneath the door of the furnace, and that the distance to the wheel l0 may be minimized, while affording maximum distance of travel of the car or furnace floor portion that is to be moved into and out of the furnace chamber.
Of course, the organization of the car-shifting mechanism within the pit ll permits the pit to be covered, as in fact it will be, with only the upper limb or edge of the wheel I0 extending above the exposed mill floor or surface I 2 in front of the furnace and over which the car travels.
It is important to note that the rack I3 is toothed wheels 9 and I0 comprise sprocket-wheels whose teeth engage the rollers of the chain, The roller-chain is secured in taut condition to the chassis [4 of the car, the attachment being effected by means of blocks 32 linked to each end of the chain and bolted to the car chassis. The body of the chain may be spot-welded, or otherwise secured, to the chassis at desired points intermediate of its length. In Figs. V and VI, the means for securing the chain at intermediate points are shown as angle clips 32a welded to intermediate links of the roller chain, and secured by means of bolts 32b to the beam Id of the car chassis. A roller-chain so organized affords many advantages over a machined gear-rack.
Fig. IV illustrates that two (or more) parallel toothed racks I31) and Be, or two lengths of roller-chain, may be arranged on the bottom of the car or floor portion 212 to be moved. In such structure, toothed wheels 9b, lb and H10, all positively driven, will be arranged to be engaged by the racks successively as the car moves. The space between successive wheels is less than the effective length of the racks. Manifestly, by such arrangement of racks and driving wheels, maximum travel of the car or floor portion of the furnace may be obtained with minimum obstruction of the floor in front of the furnace.
Within the scope of the invention defined in the appended claims, certain modifications, refinements and elaborations will occur to those skilled in the art.
We claim as our invention:
1. In a furnace comprising a furnace body and a car movable through the furnace doorway into formed of a length of roller-chain, and that the and out of the furnace chamber and subject to diiferent temperatures when in the furnace than out, said car having a chassis of metal supporting a refractory deck that forms th floor of the furnace when the car is positioned in said chamber, and means for moving the car into and out of the furnace chamber; the invention herein described in such means comprising a rectilinear length of flexible roller chain extending longitudinally of the car beneath said chassis and attached at spaced-apart points to the chassis, a sprocket wheel journaled beneath the car adjacent to the furnace doorway and engaging said roller chain, and means for selectively driving said sprocket in alternate directions of rotation,
whereby the car may be moved into and out of the furnace chamber.
2. In a furnace comprising a furnace body and a car movable through the furnace doorway into and out of the furnace chamber, and subject to diiferent temperatures when in th furnace than out, said car having a chassis of metal supporting a refractory deck that forms the floor of the furnace when the car is positioned in said chamher, and means for moving the car into and out of the furnace chamber; the invention herein described in such means comprising a rectilinear length of flexible roller chain extending longitudinally of the car beneath said chassis and attached at spaced-apart points to the chassis, a sprocket wheel journaled beneath the plane of the surface over which said car travels, with the upper edge of the sprocket wheel extending above said surface and engaging said roller chain, and means arranged below said surface for selectively driving said sprocket in alternate directions of rotation, whereby the car may be moved into and out of the furnace chamber.
3. The structure of the next preceding claim, and a second sprocket wheel journaled below said surface at an interval from the first and in alignment therewith, and adapted to engage said roller chain when the car is moved out of the furnace chamber, and means for driving said second wheel in synchronism with the first, whereby the two wheels successively engaging said roller chain are adapted to move said car through a distance substantially exceeding the length of said roller chain.
FRED H. LOFTUS. VINCENT R. TROGLIONE.
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|U.S. Classification||104/165, 74/422, 74/29, 104/50, 414/499|