US2439705A - Hot top stripper - Google Patents

Description

April 13, 1948. w. w. URMETZ HOT TOP STRIPPER Filed Aug. 24, 1944 2 Sheets-Sheet 1 14 7- TOR Y5 April 13, 1948. w. w. URMETZ HOT TOP sTRIrEn Filed Aug, 24, 1944 ZSheets-Sheet 2 INVENTQ BY [Mars/e WZ/EMETZ Patented Apr. 13 1948 T HOT TOP STRIPPER Walter W. Urmetz, Parma, Ohio, assignor to The Ferro Engineering Company, Cleveland, Ohio, a corporation of Ohio Application August 24, 1944, Serial No. 551,008

3 Claims. 1

This invention relates to improvements in hot top strippers, that is to say, mechanism operated by a crane for breaking a hot top loose from the sinkhead portion of an ingot or from the ingot mold, and transporting it to a servicing bench or other desired location. Mechanism of this character must be rugged and certain in its operation, and should be adapted for use in connection with more than one size or style of hot top in order to be of the greatest usefulness in the average steel mill.

One of the objects of the present invention therefore is the provision of a simple and rugged hot top stripper which shall be capable of easy and certain operation undervarying conditions.

Another object is the provision of a stripper mechanism which may be handled entirely by the crane operator, that is, without a helperifor adjusting the hooks, etc. i

,Another object is the provision of a stripper having readily interchangeable hook assemblies for ,use upon hot tops of diflerent sizes.

Other objects and features of novelty will appear as I proceed with the description of that embodiment of the invention which, for the purposes of the present application, I have illustrated in the accompanying drawings, in which Fig. 1 is an elevational view, partly broken away and partly in section, of a hot top stripper embodying the invention. i

Fig. 2 is an elevational view of the same taken at right angles to Fig. l. i

Fig. 3 is a horizontal sectional view taken substantially along the line 3-3 of Fig. 1, and Fig. 4 is a vertical sectional view taken substantially along the line 4-4 of Fig. 1.

When in use with a crane the device of this invention is intended to exert a lifting effort upon the trunnions H at the same time that it pushes downwardly upon the sinkhead Ill within the hot top, thereby breaking the hot top loose from the ingot or mold. Thereafter continued lifting effort applied to the trunnions ll raises the hot top sufiiciently to clear the ingot, after which it may be transported by the crane to any desired location.

The stripper comprises a housing I 2 which may be constructed of two heavy steel plates 13 disposed parallel to each other and preferably rather close together. These plates may be interconnected by suitable fastenings and spacers, as for example by pins or bolts l4 and I5 and spacing elements l6 and I1. The spacers I! have downwardly directed portions l8 which form guides for a plunger I9 that slides between the slide plates 13 of the housing and is provided on op posite sides with racks 20. Across the upper end of this plunger there is a plate 9 having projecting portions adapted to engage the top of the housing and to thereby limit the downward movement of the plunger.

Two gears 2| meshing with the racks are rotatably mounted upon shafts 22, the ends of which are mounted in the housing plates l3. These gears aremaintained in mesh with the racks 20 at all times except when the plunger is down as far as it will go, when the gears are cleared by recesses 23 in the racks and are then free to turn independently of the racks. At all times, however, the gears are maintained in correct relation to eachother by spring fingers 24 which yield readily but present sufficient frictional resistance to prevent spinningor accidental move-' ment of the gears. 1

20 As shown in the drawings the racks 2B terminate a-bovethe bottom of the plunger [9, and their lower ends may be engaged by latches 25 biased toward the latching position illustrated in Fig. 1.

These latches are pivoted at 26, and have bifurcated upper arms21 which straddle the gears 2! and bring the centers of gravity of the latches sufliciently to one side of the pivots 26 to cause the latches to swing into latching position when they are otherwise free to do so. When the latches are withdrawn and the plunger is free to descend below the position illustrated in Fig. the lower ends of the latches ride freely over the rack teeth.

Each ofthe gears 2| is straddled by the inner bifurcated end of a-lever arm 3!! which turns freely on the shaft 22. Connecting the bifurcations there is a pin 3! upon which is oscillatably mounted a pawl 32 having two lobes 33 and 34. A coil spring 35 mounted on a telescoping pin between center 35' on the lever arm and center 35" on the pawl yieldably holds either of the lobes 33 and 34 in engagement with the teeth of the gear. Shifting of the pawl from one operative position to the other may be done manually through the open end of the housing. When the lobe 33 is in operative position, as illustrated in Fig. 1, the lever arm 30 may swing downwardly. the lobe 33 of the pawl riding over the teeth of the gear with out imparting any motion to the latter. When, however, the lever arm 30 is swung upwardly, the pawl functions to lock the lever arm to the gear and rotates the latter, which communicates downward pressure to the corresponding rack 20 and thus to the plunger l9. l

plished by providing on each side of the device a knockout 138, which may be conveniently formed on the spacer block II, this knockout being so formed and positioned that when the leverar m is swung upwardly to a predetermined extent, the knockout will engage the pawl 32 and swing it against the action of spring 35 into theposition shown in broken lines on the left side of Fig. 1, that is far enough to disengage lobe 33 from the gear teeth but not far enough to throw the pawlover'center, the knockout 38 being formed with a reverse curve 38' fitting the contour of the pawl to prevent such overthrow. The gears and racks are :then released'and'are free tomove independently'of the lever arms 3%.

The levers 30 are bifurcated also at their outer ends where they carry pivots 40 upon which are mounted the lower-ends of a pair of rigid links M. The upper ends of these links are pivotally mounted ate-2 between-depending lips'of a plate 53 which may have a hole 44 therethrough to be engaged by a crane 'hook.

The lever arms -30 are closely confined within the Walls 13 f the housing, while the (links 1H are=closely confined-at their lower ends between the outer bifurcations of lever arms 33 and at their upper ends between the depending lips *of the plate 43. Hence, under all conditions the only possible movement of the lever arms and links relative to the housing I2 in the median plane of that housing, and movement in any other-direction given to the links 4| through the plate 43 is communicated i'n the same degree to the housing to produce bodily movement thereof. This is important'during the manipulation of the device required for bringing it into operative relation with a hot-top.

Two pins or bolts "45 are 'removablymounted in the walls "I3 *of the housing. These pins or bolts serve to secure to the housing a hook assembly. The different parts of this assembly are interconnected and the assembly when mounted in the'housing is'rigid with respect thereto. The assembly comprises two rails 46, to one of which there are connected permanently a pair of upwardly extending ears-4l,'perforated to receive the removable pins '\45. To the other rail 46 there are connected two legs 48, similarly provided with holes at their upper ends to receive the removable pins 45. At theends of this assembly there are mounted the two hooks 49, the latter bridging the 'spac'e'betwe'en the rails 46and secured thereto as well asto the ears 41 and the legs 48. Inorder to assist inlocating the assembly when it is to be mountedin the housing and to brace it whenso mounted, the upper ends of the hooks 49 may be turned inwardly as shown at fiii to engage with more or less wedging action the inclined portions of spacer block Hi. In the usual steel mill several of these hook assemblies so designed that the hooks are differently spaced, will be required in order toaccommodate hot tops of different sizes. The-legs 48 are so dimensioned that when they are .permittedto rest upon the upper surf-acacia hot top and are dragged across it to position the hooks 49 with respect to the trunnions II, the tips 5| of the hooks will clear the trunnions, after which a lifting effort exerted by the crane will cause the hooks to engage the trunnions, as in Fig. 2.

Operation. Assuming that the plunger is latched in its raised position, as in full lines in Fig. 1, and that the stripper-is hanging from a crane, that is that both'sets of lever arms and links are in the upper position indicated by broken lines at the left side of Fig. 1, at which time the gears are free from the lever arms 30 but are held from rotation by their engagement with theracks 2'0, the crane operator causes the jcraneto' move into position above the hot top and lowers the-stripper until the legs 48 thereof engage the upper. surface of the hot top. Next he moves the crane to drag the legs over the hot top and position the hooks underneath the trunnions H. The housing now rests upon the hot top. Next the operator lowers away, permitting the links 4| to descend and the lever arms 30 to swing down to the limit of their motion in that direction, the lobes .313 of the pawls ratcheting over the teeth of the gears. Near the bottom of the swing of the lever arms the lugs 3 push the latch arms 21 inwardly, which brings about the release of the racks when the plunger descends due to gravity, the gears 21 turning idly; Plunger it falls until it engages the upper surface ofithe sinkhead H) in the hot top, the rounded lower ends of the latches'25 riding "over the teeth of the racks 2E). The operator then causes the crane to exert an upward pull on the plate "43 .which. operates through the links toswing the lever arms 33 upwardly. The arms when movinginthis direction are locked to the gears 2i *byt'he lobes 33 Oif the pawls.

The upward movement of the lever arms first causes the gears to ride upon thenow fixed racks 20, which imparts anupward movement :to the housing I 2, lifting the legs 48off the hot top'and causing the hooks to engage the trunnions -l I, as in Fig. 2. Further lifting effort by thecran is then divided between the downward'pressur'e on the plunger and the upward pull on the hous ing providing mechanical advantage in arati'o of the order of 1 to '3 or 4. This breaks the .hot top loose from the ingot or the mold, or both, as the case may be, after which the first. effect. is continued, that is the gears climb up the :racks 20, lifting the housing and with it 'thehotjitop. When the arms 30 reach the limit of their upward movement relative to the housing they then exert their lifiting effort through thepins 22 Ian'dthe whole mechanism moves upwardly with the hot top in its grasp.-

At the upward limit of movement of the lever arms with respect to the housing the pawlslii are disengaged. The weight of the plunger causes it to fall until stopped by the plate 9 engaging the top of the housing. Thecrane is then oper-.- ated to transport the hot top to the desired location, whenitis lowered and the hooks 49 die.- connected from the trunnions l I. Next the -stri-pper is lowered over some previously prepared "upwardly extending projection which is-of -a.-char.-- acter to engage only the plunger l 9. During this operation the pawls 32 are held inoperativewbecause of their engagement with knockouts 38,-\so that the gears 2| are free to ride idlyas the housing descends relativeto the plunger. At the end of this operation the latches :25 become -eiectiveautomatically --to latch up the :plunger relativesto.

the housing, and the stripper is then ready for use upon the next hot top.

The lobes 34 on the pawls 32 do not come into use in the ordinary operation of the stripper. However, in the event that the device should be used upon a hot top which is so firmly locked to an ingot that it cannot be pulled loose, the parts may become jammed and diillcult to dislodge, in which case the operator may flip the pawls 32 over to free the lobes 33 and cause the lobes 34 to engage the gear teeth, whereupon downward pressure on the outer ends of lever arms 30 will cause the housing to move downwardly relative to the plunger and thereby disengage the hooks 49 from the trunnions II, when the whole device may be lifted out of the way and extraordinary methods employed to free the hot top from the ingot.

In cases where the sinkhead is low in the hot top and particularly where the internal diameter of the hot top is small relative to the cross-sectional size of the plunger, it may be diflicult to disengage the stripper from the hot top. In such event the difficulty may be overcome by the employment of a chain, (not shown) which may be connected to the plate 43 through a hole 60 therein and to a hook 6| in the top of the plunger. The plunger is necessarily heavy because a heavy force must be exerted through it. Its mass may be greater than the effective mass of the lever arms 30 and the links 4|, so that with the lobes 34 of the pawls in engagement with the gears,

, lowering of the plate 43 may not be effective to raise the plunger. In such case the plate 43 is lowered with the lobes 33 clicking on the gears, then the pawls 32 are shifted to cause the lobes 34 to engage the gears,after which the chain is connected between the plate 43 and the hook 6|. Now the crane is caused to pull upwardly on the plate 43 and hence on the plunger, causing the lower end of the plunger to clear the hot top. This of course turns the gears, but such turning motion is permitted by the clicking of the lobes 34 without communicating any force to the lever arms. The length of thechain is such that, when the plate 43 is in its uppermost position and the plunger is latched up, the chain will be taut; in

other words the chain is of such length that when the plate 43 is raised to its uppermost position relative to the housing the plunger will be raised sufliciently to permit latches 25 to become eifective for latching up the plunger.

Having thus described my invention, I claim:

'1. In a hot top stripper, a housing, a plunger vertically slidable therein adapted to bear at its lower end against a sinkhead, a rack on said plunger, a gear journaled in said housing meshing with said rack, a lever arm pivotally mounted to turn about the axis of said gear, a pawl on said arm adapted to engage the teeth of said gear for operatively connecting the lever arm to the gear during the upward motion of the arm, while permitting the arm to move downwardly,

independently of the gear, means carried by the,

housing for engagement with the hot top to exert 6 a lifting force thereupon in opposition to the said plunger depressing force, and a knockout for said pawl at the upper limit of motion of saidlever arm, leaving said gear free to turn in response to movement of said plunger.

2. In a hot top stripper, a housing, a plunger vertically slidable therein adapted to bear at its lower. end against a sinkhead, a rack on said,

plunger, a gear journaled in said housing meshing with said rack, a lever arm pivotally mounted to turn about the axis of said gear, a pawl on said arm adapted to engage the teeth of said gear for operatively connecting the lever arm to the gear during the upward motion of the arm, while permitting the arm to move downwardly independently of the gear, means carried by the housing for engagement with the hot top to exert a lifting force thereupon in opposition to the said plunger depressing force, latching means for holding said plunger in a raised position, said latching means being biased toward latching position, and means on said arm for withdrawing said latching means when said arm is lowered to a predetermined extent.

3. In a hot top stripper, a housing, a plunger vertically slidable therein adapted to bear at its lower end against a sinkhead, a rack on said plunger, 2. gear journaled in said housing meshing with said rack, a lever arm pivotally mounted to turn about the axis of said gear, a pawl on said arm adapted to engage the teeth of said gear for operatively connecting the lever arm to the gear during the upward motion of the arm, while permitting the arm to move downwardly independently of the gear, means carried by the housing for engagement with the hot top to exert alifting force thereupon in opposition to the said plunger depressing force, latching means for engagement with the lower end of said rack to hold said plunger in a raised position, said latching means being biased toward latching position but being adapted to ride freely over the teeth of the rack, and means on said arm for withdrawing said latching means when said arm is lowered to a predetermined extent.

WALTER W. URMETZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 832,758 Taylor Oct. 9, 1906 1,059,667 Gathmann Apr. 22, 1913 1,420,555 Klasing June 20, 1922 1,474,785 Kruger Nov. 20, 1923 1,526,125 Fellows Feb. 10, 1925 1,957,462 Kress May 8, 1934 2,317,565 Urmetz Apr. 27, 1943 FOREIGN PATENTS Number Country Date 441,284 Germany Feb. 28, 1927

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