US3332674A - Travelling grate machine with drive - Google Patents

Description

July 25, 1967 5, M COULTER ET AL 3,332,674

TRAVELLING GRATE MACHINE WITH DRIVE Filed Aug. 16, 1965 4 Sheets-Sheet l INVENTOR. STANLEY M.COULTER LEONARD J. BACHMAN BY (M MI their ATTORNEYS July 25, 1967 5 COULTER ET AL 3,332,674

TRAVELLING CRATE MACHINE WITH DRIVE Filed Aug. 16, 1965 4 Sheets-Sheet INVENTOR. STANLEY M COULTER LEONARD J. BACHMAN #heir ATTORNEYS July 25. 1 67 s. M. COULTER ET AL 3,332,674

TRAVELLING GRATE MACHINE WITH DRIVE Filed Aug. 16, 1965 4 Sheets-Sheet 3 INVENTORS. STANLEY M.COULTER LEONARD J. BACHMAN July 25, 1967 5, CQULTER ET AL 3,332,674

TRAVELLING GRATE MACHINE WITH DRIVE Filed Aug. 16, 1965 4 Sheets-Sheet 4 L //3O \lk I F |g.5. u I

INVENTOR. f flk fifibfi l F|g.6. I BY their ATTORNEYS United States Patent 3,332,674 TRAVELLING GRATE MACHINE WITH DRIVE Stanley M. Coulter, Ben Avon, and Leonard J. Bachman,

Coraopolis, Pa., assignors to Dravo Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug. 16, 1965, Ser. No. 479,769 7 Claims. (Cl. 266--21) This invention relates to travelling grate machines such as are used in the sintering and pelletizing of iron ore, and particularly to the driving mechanism for such a machine.

In travelling grate machines of the type to which the present invention relates, a succession of separate pallets move in a generally horizontal path from a charging end to a discharge end over a series of windboxes. At the discharge end the pallets are carried by a sprocket wheel to a return track along which they travel to the charging end. In moving around the sprocket at the discharge end, the charge in the pallets is dumped. At the charging end the pallets are raised by a power-driven sprocket to the upper strand. As each pallet in turn moves into place at the starting or charging end, it pushes the line or strand of abutting pallets ahead of it to the discharge end and the pallets being pushed from the discharge end power the sprockets that dump and lower them to the return strand. While the pallets have flanged wheels that roll on rails and support most of the weight, each pallet has at least one seal at each end that rides on a sealing strip so that air or gases will flow to and from the several windboxes through the pallets and the charge contained thereon. As a result of the length of the machine, the weight of the charge, the difliculty of providing lubrication both because of heat and dust, the contact forces generated between the pallets moving into position .at the charging end of the strand and pushing the pallets on the strand ahead is enormous. Consequently, a very great strain is imposed on the driving mechanism through which the sprockets are rotated. There is generally provided a gear wheel on the sprocket wheel shaft, and this shaft is journaled in the head frame of the machine. A motor and reduction gear train rotate this gear, and these mechanisms are supported usually independently of the head frame, but in the same building structure as the head frame. This results in the problem of maintaining proper alignment and relation of the driving pinion and the drive gear which in engages.

The present invention has for its principal object to provide a drive which will eliminate the problems of alignment as heretofore encountered, and which will also distribute the driving forces so that they are not concentrated on a single tooth of the driving gear or driving pinion.

This is accomplished by suspending a beam-like rigid frame from the drive shaft for the sprockets, which shaft carries the main driving gear, from hearings in which the shaft rotates. A driving motor, reduction gear, and pinions for engaging the main driving gear wheel at each end of the rigid frame, the driving pinions of the two units being diametrically opposite.

The invention and its further objects and advantages will be more fully understood by those skilled in the art by reference to the following detailed description of a machine embodying our invention in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a fragmentary side elevation of the charging end of a travelling grate machine showing the head frame, drive shaft, and a portion of the track, parts being broken away to show a portion of the sprocket wheel and a portion of the drive wheel with the driving mechanism not shown;

3,332,674 Patented July 25, 1967 FIG. 2 is a transverse section in the plane of line II II of FIG. 1, but with the drive gear being also shown;

FIG. 3 is a side elevation of the drive gear housing and the drive gear assembly;

FIG. 4 is a top plan view of the drive shown in FIG. 3;

FIG. 5 is a fragmentary section in the line VV of FIG. 3; and

FIG. 6 is a similar fragmentary view in the plane of line VI--VI of FIG. 4.

Referring first to FIGS. 1 and 2, 2 designates the top rails of a travelling grate machine along which the pallets 3 are moved in the direction of the arrow, and 4 are the bottom rails along which the pallets move in the'reverse direction and in inverted position toward the lifting sprockets 5 at the charging end. The lifting sprockets raise the pallets from the lower level to the upper one, turning them again to the upright position as they elevate the pallets. There are two of these sprockets, one at each side of the machine, and they are both fast on a common shaft 6 mounted in bearings 7 in a rigid structural steel frame, designated generally as 8, and herein sometimes referred to as the head frame. This much of the machine is not substantially different from other travelling grate machines, the pallets themselves having the usual grate arrangement in the bottom.

According to the present invention, one end of the shaft projects at one side well beyond the head frame, and has a drive gear wheel 10 keyed thereto. This gear wheel preferably has two sets of teeth 11 on its periphery disposed angularly to each other in herringbone fashion. There are two bearing assemblies on the projecting end of the shaft, one at each side of the drive gear wheel 10, one of these, designated 12, being at one side of the gear wheel and one, designated-13, at the other. These bearings are fixed to the top of a drive frame 14 comprised of two parallel I-beams 15 extending horizontally below the shaft at right angles thereto, the frame extending roughly about the same distance each from the bearings 12 and 13 laterally beyond the periphery of the drive gear wheel 10. There is a housing or enclosure 16 secured to the top of the frame over and around the drive gear, and there is an enclosed oil pan 17 secured to the under side of the frame enclosing the lower portion of the drive gear.

On each end of the drive frame is a motor 20, the drive shaft 21 of which is coupled to a reducing gear schematically indicated at 22, which drives a sleeve 23 that is coupled at 24 to a pinion shaft 25 on which are two pinions 26 that mesh with the herringbone teeth of the drive gear. The motors, reduction gears and pinions are matched in size, weight and power so that they are substantially in balance with each other. The reducing gears, as seen in FIG. 6 are offset to one side of the longitudinal center of the frame so that the pinions 26 are in line with the drive gear 10. The weight of the drive unit comprising the motor and reducing gear at each end of the beamlike drive frame counterbalance each other, and an extension 27 at one end of the drive frame is secured to a flexible cable 28 that is anchored at opposite ends, not shown, to the head frame structure or some other fixed locations to hold the drive frame from rotating about the main drive shaft on which the sprocket wheels are fixed. A flexible cable is used because it will not transmit any stresses on the beam-like frame sideways or endwise due to any relative movement of the head frame in the building or to the drive shaft.

By having the drive units on the frame suspended by the sprocket wheel shaft, the relation of the drive to the driving gear is fixed and cannot be affected by relative expansion and contraction under thermal changes or by stresses such as have heretofore caused alignment difl'lculties. By using two motors and two reducing gears, the

stresses on the gear teeth are divided and applied to the driving gear at diametrically opposite locations, and at the same time. the suspended driving beam is balanced. The frame itself is below the axis of the drive gear so that the centers of the pinions 26 are on a diameter of the driving gear, and the center of gravity of the frame is below the axis of the shaft. Further stability is provided by a counterweight 30 under each end of the beam, one being about equal to the other. These further lower the center of gravity and increase the inertia of the driving frame, and while the reduction gears are offset to one side of the frame, these weights, as shown in FIG. 6, are offset to one side of the frame, thereby tending to equalize the overturning momentum about the axis of the driving frame. The herringbone teeth on the pinions 26 and drive gear tend to equalize end thrust on the shaft 25, further eliminating alignment problems.

The invention may be modified as to the particular construction of parts within the contemplation of our invention and under the scope of the following claims.

We claim:

1. In a travelling grate machine having upper and lower tracks along which a succession of pallets are moved and a pair of sprocket wheels at one end for elevating pallets from the lower track to the upper one, said sprocket wheels being fixed on a drive shaft having a drive gear wheel at one end, with a frame in which said shaft is journaled, the invention comprising a drive for the drive shaft, said drive comprising:

a rigid beam-like frame,

bearings on said beam-like frame in which the drive shaft is rotatable and by which the frame is hung from the shaft below the axis of the shaft,

a drive motor at each end of the beam-like frame,

a reduction gear on each end of thebeam-like frame,

each driven by one of said motors,

a pinion shaft driven by each reduction gear, each pinion shaft having a pinion thereon meshing with said drive gear wheel for rotating said wheel,

and means for restraining said beam-like frame against the free rotation about the drive shaft.

2. A travelling grate machine as defined in claim 1 wherein said last-named means is a flexible cable attached to one end of the beam-like frame with its opposite ends anchored at fixed points, said fiexible cable restraining the frame against rotation but being incapable of transmitting any pull on the beam-like frame sideways or in the direction of its length. 1

3. A travelling grate machine as defined in claim 1 in which the centers of the pinion shafts at opposite'ends of 4 the frame are diametrically opposite the center of said drive shaft.

4. A travelling grate machine as defined in claim 1 in which the centers of the pinion shafts at opposite ends of the frame are diametrically opposite the center of said drive shaft, said motors, reduction gears and pinions being of the same size and weight.

5. A travelling grate machine as defined in claim 1 in which the centers of the pinion shafts at opposite ends of the frame are diametrically opposite the center of said drive shaft, said motors, reduction gears and pinions being of the same size and weight, the reduction gears being to one side of the drive gear wheel and the longitudinal axis of the beam-like frame, and a counterweight under the beam-like frame adjacent each end thereof to lower the center of gravity of the beam-like frame and stabilize it and balance the opposite ends of the beam-like frame.

6. A travelling grate machine as defined in claim 1 in which the centers of the pinion shafts at opposite ends of the frame are diametrically opposite the center of said drive shaft, said motors, reduction gears and pinions being of the same size and Weight, the reduction gears being to one side of the drive gear wheel and the longitudinal axis of the beam-like frame, and a counterweight under the beam-like frame adjacent each end thereof to lower the center of gravity of the beam-like frame and stabilize it and balance the opposite ends of the beam-like frame, the counterweights being offset to the side of the axis of the beam-like frame opposite the side on which the reduction gears are offset to equalize the overturning momentum about the axis of the frame.

7. A travelling grate structure as defined in claim 1 in i which the drive gear wheel has herringbone teeth and the pinions that mesh therewith have corresponding teeth.

References Cited UNITED STATES PATENTS 1,495,930 5/1924 Sing 74-665 X 1,617,561 2/ 1927 Alexovits 26621 2,518,781 8/1950 Hindmarch' 74661 2,670,947 3/1954 Duncan 2662l 2,745,659 5/1956 Osojnak 266-21 2,915,167 12/1959 Berger 198-127 2,997,608 8/1961 Musser 198-127 X 3,141,544 7/1964 Hansen 266-21 X 3,213,711 10/1965 Kieboom 74-661 X J. SPENCER OVERHOLSER, Primary Examiner. V

R. S. ANNEAR, Assistant Examiner.

Claims (1)

1. IN A TRAVELLING GRATE MACHINE HAVING UPPER AND LOWER TRACKS ALONG WHICH A SUCCESSION OF PALLETS ARE MOVED AND A PAIR OF SPROCKET WHEELS AT ONE END FOR ELEVATING PALLETS FROM THE LOWER TRACK TO THE UPPER ONE, SAID SPROCKET WHEELS BEING FIXED ON A DRIVE SHAFT HAVING A DRIVE GEAR WHEEL AT ONE END, WITH A FRAME IN WHICH SAID SHAFT IS JOURNALED, THE INVENTION COMPRISING A DRIVE FOR THE DRIVE SHAFT, SAID DRIVE COMPRISING: A RIGID BEAM-LIKE FRAME, BEARINGS ON SAID BEAM-LIKE FRAME IN WHICH THE DRIVE SHAFT IS ROTATABLE AND BY WHICH THE FRAME IS HUNG FROM THE SHAFT BELOW THE AXIS OF THE SHAFT, A DRIVE MOTOR AT EACH END OF THE BEAM-LIKE FRAME,

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