US2306055A - Soaking pit crane - Google Patents

Description

Dec. 22, r1942. R. J. HARRY SOAKING PIT CRANE 3 Sheets-Sheet l Filed oct. 24, 1940 Hah/7 Dec. 22, 1942. R. J. HARRY y soAKINGPIT CRANE Filed Oct. 24, 1940 3 Sheets-Sheet 2 Patented Dec. 22, 1942 stares "raar orrlce SOAKING PIT CRANE Robert J. Harry, Alliance, Ohio Application October 24, 1940, Serial No. 362,593 7 claims. (ci. 2121-11) This invention relates to lifting cranes and, in particular, to cranes for placing' steel'ingots in a soaking pit and removing them therefrom.

. Soaking pit cranes have vheretofore been of two principal types, i. e., the high and the low type, these terms referring generally to the amount of head room required by` cranes of the two types. The conventional high type crane comprises a trolley adapted'to traverse a cranef bridge and having a vertically reciprocable rack column slidable in a tower-like structural guide frame extending a considerable distance above yand below the trolley, the rack column having ingot-gripping tongs at its lower end. In 'the low type crane, the structural frame in which the column reciprocates depends below the trolley. In both types, the presence of the guide frame adds materially to the cost and weight of the crane. A further objection to the conventional construction is that when the guide frame strikes an obstacle such as an ingot or mold, as sometimes happens, despite the greatest care on the part of the operator, the stress of impact' is transmitted directly to the crane because of the rigid mounting of the frame on the trolley. In the 1ow'type crane, furthermore, rotation of the tongs is effected by a motor mounted on the reciprocating column and flexible cables are 'necessary to supply energy to the motor. These cables are difficult to maintain in good operating condition. The operators platform, in the low type crane, is disposed below the traveling bridge to provide good visibility, but this brings the op erator objectionably close to the furnace when charging or removing ingots.

Y I have invented a novel type of crane particularly adapted for soaking pit service, which overcomes the aforementioned objections to such cranes as constructed heretofore. In -a preferred embodiment of the invention, I eliminate the conventional guide frame altogether and provide a lifting block adapted to be suspendedv below a trolley movable along a traveling bridge. Tongactuating means carried by the block cooperate with tongs pivoted adjacent the lower end of a shaft depending from the trolley and extending through the block. The shaft also extends through a guide mounted on the trolley for universal movement. A motor and a suitable drive for turning the shaft are mounted on the guide.

A second block below the trolley is adapted to raise or lower the shaft, thereby causing opening or closing of the tongs. Cables traversing the sheaves of both blocks are secured at one end to a drum on the trolley. The other ends of the cables traversing the sheaves of the shaft-supporting block are secured to another drum on the trolley, while the other ends f the cables traversing the sheaves of the lifting blocks are secured to anchorages on the trolley. Thus by operating the first-mentioned drum the crane may be raised or lowered. ABy operating the second drum only, the tongs may be actuated. Restoring springs tend to hold the shaft normally in substantially vertical position.

The preferred embodiment of the invention outlined above is illustrated in the accompanying drawings to which reference is made for a detailed description. In the drawings:

Fig. l is a side elevation with parts broken away;

Fig. 2 is a partial sectional view taken along the plane of lines II-II of Fig. 1 showing parts in elevation;

Fig. 3 is a plan View with parts omitted for the sake of clearness;

Fig. 4 is a partial sectional view taken substantially along the` plane of line IV-IV of Fig. 1; and

Fig. 5 is a vertical central section through a Amodified form of universal mounting, showing the shaft guide therein in elevation.

Referring now in detail to the drawings, a trolley I0 comprises a frame II, conveniently a cast- -v ing having box-like cross members I2 and I3 at opposite ends thereof providing journal boxes for stub shafts I4 and a through shaft I4 on which wheels I5 are disposed. The wheels I5 travel on rails I6 secured to the girders I1 of a traveling crane bridge of any suitable construction. (The girders are omitted from Fig. 3)

The frame II has a oor or deck I8. A motor I9 secured to the deck is coupled to a shaft journaled in a gear case on which a pinion 2| is keyed. The pinion 2l meshes with .a gear 22 lkeyed to an auxiliary shaft journaled in the case 20. A pinion 23 keyed to the same shaft as the gear 22 meshes with a gear 24 on the shaft I4.

By virtue of the mechanism described, operation of the motor I9 causes the trolley I0 to travel along the rails I6.

A block housing 25 is suspended below the trolley I0. The housing comprises side plates 26, end walls 21, and a cover 28. The side plates 26 are welded at their lower ends to a casting 29 comprising spaced sheave blocks 33 and 3I and a hub 32 therebetween. Sheaves 33 are journaled on pins 34 in the blocksand are traversed by cables 35. As shown in Fig. l, one end of each of the cables 35 is secured to a drum 36 on the trolley, while the other ends of the cables are secured to anchorages 31 on the trolley. Each of these anchorages comprises a ball 38 disposed in a split spherical seat on the transom I3, a bolt 39 having a clevis at one end to which the cables are secured, and a spring cushion 40 on the other end. The cushions 45 extend through holes 48 in the deck I8.

The drum 36 is journaled in bearings 4| and 4|' on the car and is driven by a motor 46 also mounted thereon. The motor 42 is coupled to the worm shaft 43 of a worm reduction gear 44 including also a worm wheel 45. The worm Wheel is keyed to a shaft 46 journaled in bearings 41 and 41. Pinions 48 in gear cases 49 are keyed to the shaft 46 and mesh with gears 50 formed integral with the drum 36. A cable slot 5| is formed in the deck I 8 of the trolley to receive the cables 35. The motor 42 is provided with a brake 52 and the drum 36 with a brake 53 rof known construction. f f

A casting 54 comprising spaced sheave ' blocks 55 and 56 and a hub 51 therebetween is movable in the upper portion of the housing 25. Sheaves 58 are journaled on pins 59 in the blocks 55 and 56, the outer'ends of the pins projecting' through windows 60 in the end walls 21 ofthe housing, thereby limiting movement of the casting in the housing. Cables 6| traverse the sheaves 58; One end of each cable is secured to the drum 36. The other ends of the cables 6| are secured to a. drum 62. The drum 62 is journaled on bearings 63 and 63 on the deck I8 of the trolley I9 and is 'driven by a motor 64 through a worm reduction gear 65. The motor is coupled to the worm shaft 66 of the reduction gear which has a worm meshing with a worm wheel 61 keyed to a cross shaft 68 journaled in the reduction gear and in' -agear case 69. A pinion 18 is the case 69 is keyed to the shaft 68 and meshes with a gear 1| formed integral with the drum 62. A brake 12 is provided at the free end of the worm shaft 66.

It will be understood from the foregoing that operation of the motor 4 2 while the drum 62 remains stationary will cause the drum 36 to take up or pay out both cables 35 and cables 6| at the same rate, thereby raising or lowering the blocks 30, 3| and 55, 56 at the same rate, i. e., without changing their relative positions in the housing 25. On the other hand, operation of the motor 64 while the drum 36 is stationary will cause the drum 62 to take up or pay out the cables 6| Without affecting the cables 35, thereby raising or lowering the blocks 55, 56 in the housing 25. I utilize this movement to effect operation of ingot-gripping tongs about to be described.

A sleeve 13 has a reduced upper end inserted in the hub 32 of the casting 29 forming part of the block housing 25. The sleeve is rotatably supported in the hub on a thrust bearing 14, a washer 15 and a nut l16 on the upper end of the sleeve transmitting the vertical load on the latter to the bearing.

Ingot-gripping jaws 11 are pivoted at 18 on a cross-head 19. The cross-head 19 is secured by a key 88 to a shaft 8|. The shaft 8| extends downwardly through a guide 82, through the hub 51 of casting 54 and through the sleeve 13. Rearward extensions 83 on the jaws 11 have rollers 84 cooperating lwith oppositely inclined surfaces 85 formed on the sleeve 13. By this construction, the jaws are actuated to their closed positions indicated in chain lines in Fig. 1 on downward movement of the shaft 8| relative to the sleeve 13.

The shaft 8| is supported by a thrust bearing 86 formed in the hub 51 of the casting 54. A collar 81 secured to the shaft 8| by a key 88 transmits the load of the shaft to the thrust bearing.

The shaft 8| is preferably of square or other non-circular section, as shown in Figs. 3 and 4. The sleeve 82 has a cylindrical bore therethrough of such diameter as to permit rotation of the shaft therein. By virtue of the thrust bearings 14 and 86, rotation of the shaft 8| does not turn the block housing'25. The sleeve 13 turns on the thrust bearing 14 with the shaft 6|, the lower portion of the bore through the sleeve being reduced and of square section to t the shaft snugly.

The sleeve 82 is pivotally supported on trunnions 89 by a ring 90. 'I'he ring 90, in turn, is pivotally supported on trunnions 9| at right angles to the trunnions 89, in bearings 92 on the deck I8 ofthe trolley I 0. The double-trunnion mounting of the sleeve 82 permits universal movement of the sleeve and the shaft 8| extending therethrough. It will be understood that the deck I8 has an opening of suitable size between the bearings 92 to permit the desired angular movement of the sleeve 82. Tension springs 82' secured to the lower end of the sleeve 82 and to any suitable anchorages on the trolley l0, serve normally to maintain the sleeve and the shaft 8| in substantially vertical position.

Adjacent the upper end of the sleeve 82, a gear case 93 is formed enclosing a Worm wheel 94. The worm wheel 94 has a square hole therein adapted to receive the shaft 8|. A motor 95 is mounted on a shelf 96 extending laterally from the sleeve 82. The motor 95 is coupled to a shaft journaled in a gear case 91 and a pinion 98 is keyed on the shaft. The pinion meshes with a gear 99 on a Worm shaft |00 in the case 91. A worm on the shaft I 00 meshes with the worm wheel 94. A drive is thus provided for turning the shaft 8| in the sleeve 82. This permits the tongs 11 to be manipulated angularly as well as vertically in order that they may obtain the desired hold on an ingot when picking it up and may turn the ingot slightly in opposite directions when disposing it on the iloor of the furnace in order that it may be firmly bottomed thereon.

The operation of the apparatus as a whole will probably be apparent from the foregoing description. In any event, Fig. 1 illustrates, in full lines, the up-raised, open position of the tongs 11. With the tongs in this position, the crane bridge |1 and the trolley l0 are operated along their track rails to spot the tongs approximately over an ingot to be picked up and charged into the soaking pit. The mot-or 42 is then energized to operate the drum 36, thereby lowering the block housing 25 without changing the relative positions of the castings 29 and 51. When the tongs have been positioned adjacent the top of the ingot, the motor 42 is stopped. The motor 64 is then started to drive the drum 62 in such direction as to pay out the cables 6|. As already explained, this permits the casting 51 to descend in the housing 25. since the weight of the shaft 8|, which is considerable, is carried entirely by the collar 81 resting on the thrust bearing 86, the shaft descends with the casting 51. The tongs 11 thus move downwardly and are swung into gripping engagement with the ingot by the engagement of their rollers 84 with the sloping surfaces on the sleeve 13. The

sleeve 13, of course, remains stationaryas long as the drum 3.6 is stopped.

The Weight of the shaft 8| issuiiicientto cause tongs to engage the ingot firmly enough to permit lifting thereof and when such engagement has been secured, the motor 64 is stopped. Accurate y'stopping of the motor is unnecessary, however, since a slight amount of slack in the cable 65 will do no harm.

After securing a grip on the ingot, the crane operator starts the motor 42 to drive the drum 36 in such direction as to take up on the cables 35. This also takes up the cables 6| at the same rate, but the relative positions of the castings 29 and 51 are not altered, whereby the gripping engagement of the tongs on the ingot is not disturbed. The weight of the ingot is transmitted by the tongs to the surfaces 85 of the sleeve 13 and thence to the casting 29 and blocks 30 and 3|.

When the ingot has been raised suiiiciently to clear obstructions on the floor` adjacent the soaking pit, the motor 42 is stopped and the girders |1 and trolley Ill are moved to bring the ingot over the pit. The motor 42' is then operated in such direction as to pay out the cables 35 and El. The ingot is thus lowered into the pit, but since the relative positions of the castings 29 and 51 are still unchanged, the grip of the tongs on the ingot is not affected. s

When the bottom of the ingot strikes the floor of the pit, the motor 42 is stopped. The motor 95 may then be operated for short periods in opposite directions to turn the shaft 9| and the tongs 11 as previously described, in order to bottom the ingot firmly on the pit floor. When this has been done, the motor B4 is operated to drive the drum 62 in such direction as to take up the cables 6|. This raises the casting 51 and the shaft 8| relative to the casting 29 and sleeve 13, thereby permitting the gripping ends of the tongs 11 to swing outwardly and releasing the ingot. Thel motor 64 is then stopped and the motor 42 again operated to raise the castings, block and tongs out of the pit. Similar procedure is followed to remove an ingot from the pit.

Fig. illustrates a modification in which shaft 8| extends through a guide IDI having a spherical enlargement |92 thereon disposed in a split spherical seat ID3 on the deck IB -of the trolley I0. It will be apparent that the structure of Fig. 5 differs from that of Figs. 1 and 3 only in that in the former the ball-and-socket joint provided b-y the spherical enlargement |92 and the seat |03 constitutes a universal mounting for the guide I9 I, instead of the double-trunnion mounting of the guide 82.

t will be apparent from the foregoing description and explanation that the invention is characterized by numerous important advantages over soaking pit cranes as heretofore constructed. In the first place, the elimination of the conventional guide frame considerably reduces the weight and cost of the crane. A further advantage is that if the depending portion of the crane or an ingot in the tongs strikes an obstruction while moving, the suspended mechanism yields by swinging on its universal mounting, thereby saving the trolley and crane bridge from the impact stresses which would otherwise be transmitted thereto. The universal mounting of the vertical shaft, furthermore, makes it unnecessary to spot the tongs accurately relative to the ingot since no injury to the crane will result from lifting an ingot which is slightly off center relative to the shaft. The only'thing that will happen is that when the tongs close on the ingot, the

' shaft will swing slightly into alinement therewith. The motor for turning the tongs does not move up and down so it is unnecessary to provide long, flexible cables for supplying'energy thereto.

The absence of the guide frame for the vertically moving portionsof the crane gives the operator. a good view of the tongs While standing on thede'ck |8 where he is protected to some extent from the heat of the furnace.

Although I have illustrated and described herein but a preferred embodiment of the invention with a modification of a portion thereof, it will be recognized that changes in the construction and arrangements of parts described herein may be made without departing from the spirit of the inventionor the scope of the appended claims.

I claim:

l. A .soaking-pit crane comprising a trolley adapted to move along a traveling bridge, a guide mountedon said trolley, a block housing suspended ybelow the trolley, a shaft movable axially through said guide and' housing, pivoted tongs adjacent the lower end of the shaft, a sheave block fixed in said. housing, a tong-actuating member secured thereto, said shaft being slidable through said member and effective on movement relative thereto to open or close the tongs, a sec-A ond sheave block movable in said housing, a collar secured to the shaft and bearing on said second block, cables traversing sheaves in both said blocks, a drum on the trolley, one end of the cables traversing the sheaves of both blocks being secured to said drum, and a second drum on the trolley, the other end of the cables traversing the sheaves of the movable block only being secured to said second drum, the other ends of the cables traversing the Vsheaves of the fixed block being anchored to said trolley, whereby operation of said first-mentioned drum raises or lowers both blocks simultaneously and operation of the second drum raises or lowers only the movable sheave.

2. A crane comprising a trolley, a shaft depending therefrom, a guide through which said shaft extends, means on said trolley mounting said guide for universal movement, tongs pivoted on said shaft, tong-actuating means carried below said trolley, said shaft being movable relative to said tong-actuating means, means on said trolley for raising and lowering said shaft to cause said tong-actuating means to open and close said tongs, and a motor and gearing mounted on said guide for rotating said shaft therein.

3. A crane comprising a trolley, a shaft dependingtherefrom, a guide through which said shaft extends, means on said trolley mounting said guide for universal movement, tongs pivoted on said shaft, tong-actuating means carried below said trolley, said shaft being movable relative to said tong-actuating means, means on said trolley for raising and lowering said shaft to cause said tong-actuating means to open and close said tongs, and means wholly mounted on said guide for rotating said shaft.

4, A soaking pit crane comprising a trolley, a

guide, means on the trolley mounting the guide for universal movement, a shaft depending through said guide, pivoted tongs carried on said shaft adjacent the lower end thereof, a tongactuating memberA adjacent said shaft, said member being effective on movement of the shaft relative thereto, means on said trolley for raising and lowering said shaft and operating said member, a motor carried on said guide, land gearing driven by said motor effective to turn said shaft. 1

5.. A soaking pit crane comprisingf a trolley, a sheave block disposed in a housing below the trolley, a shaft extending downwardly from said trolley through said housing, a bearing guide, positionedv on said trolley in which said shaft is slidable longitudinally, means c mounting said guide for universal tilting movement, means wholly mounted on, said guide for rotating said shaft, tongs carried on said shaftadjacent the lower end thereof, a tong-actuating member secured to said block, said shaft being movable through saidy block and' effective on such movement to open or close the tongs, a second sheave block movably mounted in said housing, thrust bearing means whereby said second block supports said shaft, cables traversing sheaves in both said blocks, and means on the trolley for taking up or lowering selectively either or both said blocks.

6; A soaking'pit crane comprising a trolley, a guide positioned on said trolley, means mounting said guide for universal tilting movement, a sheave block suspended below the trolley, a shaft extending downwardly from said trolley Ithrough said guide and block, tongs carried on said shaft adjacent the lower end thereof, a tong-actuating member secured tosaid bloei-:,said shaft being axially movable through said guide and block and effectiveron such movement to open or close the tongs, means wholly mounted on saidl guide for rotating said shaft, a second sheave blocky suspended below the trolley, means whereby said second block supports said shaft, cables traversing sheaves in both said blocks, and means on the trolley for taking up orlewering selectively either or both said blocks.

7. A soaking pit crane comprising a trolley, a generally vertical sleeve mounted on the trolley, means supporting the sleeve for universal tilting movement, a shaft depending through said sleeve, pivoted tongs carried on said shaft adjacent the lower end thereof, a tong-actuating member adjacent; said shaft, said member being effective on movement of the shaft relative thereto, means wholly carriedon said sleeve for rotating said shaft therein, and suspension means for said shaft and member including means for raising or lowering the shaft and member together and means for raising or lowering said shaft relative to said member.

ROBERT J. HARRY.

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