Field of the Invention

This invention relates to a deburrer assembly which has particular, thoughnotof courseexclusive, application as a slab deburrer in continuous casting.

Background Art

One method of removing the burrs which remain at the undersideedges of slabscut fromcontinuouslycast strands is to knock of the burr with a deburrer roll assembly. Such an assembly typicallycarries multiple sets of radiallyprojecting hammers which are rotatablymounted on longitudinally extending rods and remain in the radial position due to centrifugal force when the roll is rotated. The clearance in the hammer mounting ensures that thehammeralways contacts theundersideoftheslab and the stored energy of the hammer is thought sufficient to remove the respective burr segment projecting below the surface

of the slab. It is found in practice that existing deburrer roll assemblies donot reliablyremoveburrs from slabs cast in steels of higher strength grades. It is therefore an object of the invention to provide animproveddeburrerroll assemblywhich at leastimprovesthereliabilityofburrremovalwithawiderrange of steel grades.

Summary of the Invention

It has been realised in accordance with the invention that the failure of the hammers to reliably and completely remove burrs from slabs cast in steels of higher strength grades arises becausethehammersbouncebackofftheburrratherthanbreaking it away. It is thus proposed, in accordance with the invention, toproviderestraints tobackupthehammers againstthetendency to bounce off the burrs but still retain radial freedom. The invention accordingly provides, in one aspect, a deburrerassemblywhichincludesanelongatebodysuchas a roll, andmultiplehammerelements rotatablymountedtoandpro ecting radially of the body. Restraint means are mounted to the body for substantially restraining the hammer elements against rotation. When the body is rotated aboutanaxisparallel to its longitudinal dimension to revolve the hammer elements, the restraintmeans support thehammer elements against rotation in response to tangentially or circumferentially directed force The invention further provides, in another aspect, a deburrerassemblywhichcomprisesanelongatebody, andmultiple hammer elements mounted to and projecting radially of the body. Respective restraint means are mounted to the body and disposed adjacent thehammer elements at a finitedistance from the outer ends of the respective hammerelements. Whenthebody is rotated about an axis parallel to its longitudinal dimension to revolve the hammer elements, these restraint means support the hammer elements against tangentially or circumferentially directed forces. Theelongatebodyispreferablyarollcoaxialwiththe axis of rotation and the assembly may further include means mounting

the roll for rotation about its axis. The hammer elements are preferably arranged in angular spaced sets and these sets are themselves successivelyoffset the axial direction. The hammer elements may be rotatab supportedonlongitudinallyextending rodswhich areinturnhe by annular plates welded at spaced intervals to the roll. T restraint means may then comprise respective rods or bars ea secured to two ormore of theseplates, forexamplebywelding respective slots in the plates.

Brief Description of the Drawings

The invention will be further described, by way of exampl only, with reference to the accompanying drawings, in which FIGURE 1 is a side elevational view of a roll assembl according to the invention; FIGURES 2 and 3 are cross-sections on the lines 2-2 and 3- in Figure 1, in the latter case also showing a burred slab abou to be struck; FIGURES 4 and 5 are cross-sections on the lines 4-4 and 5- in Figure 2, the latter also being an enlargement of a detai from Figure 1; and FIGURE 6 is a detailed elevation showing one of the hamme sets.

Best Modes of Carrying out the Invention

The illustrated deburrer roll assembly 10 includes a elongate body in the form of a cylindrical roll 12, multipl hammers 14 arranged in sets 15 of five hammers each with th hammers projecting laterally or radially of roll 12, an respective pairs of longitudinally extending restraint bars 1 associated with each hammer set 15. Roll 12 has end-fittings 1 by which the roll is typically mounted in suitable heavy dut bearings (not shown) in a continuous caster roller table. The hammers 14 and restraint bars 16 are secured to roll 1 bymeans of annular support plates 18 arranged at equally space intervals along the roll. Each plate 18 is welded at its inne

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periphery to a respective outstanding integral land 20 on t roll 12 (FIGURE 4). The two inner edges of each plate a chamfered to provide grooves for the welds 22. Eachplate 18 h eight eguiangularly spaced apertures 24 and the successi apertures are aligned to receive and retain eight rods 26 whi extend parallel to the axis of the roll just out from the lan 20 and are retained in place at the end plates 18 and 18b by di keepers 28 fastened to the end plates. Hammers 14 have apertures 13 (FIGURE 6) at oneend bywhi they arerotatablysupportedontherespectiverods 26. These 15 eachinclude end hammers 14a with axially enlarged outer en and three intermediatehammers 14bwith shallowbosses 14c abo their apertures 13 to serve as spacers. Each hammer includes strikerhead 30 of dovetail cross-sectionwhichprojects beyo the envelope defined by the outer rims of plates 18, as best se in FIGURES 2 and 3. The sets 15 of hammers 14 are arranged in aligned adjace pairs in successive spaces between plates 18 with successi pairs offset by 45°. The mounting of the hammers is such as allow slight radial movement of the hammers in order compensate for small variations in the height at which the sla come through and for curvature of the slab surface. Restraint bars 16 are of rectangularcross-section and l to either side of each pair of hammers, thus extending from plate 18 to the second next plate. The restraint bars are he in matching slots 32 in plates 18 so that the bars do n radiallyproject beyond the plates. They are welded in place welds 34 (FIGURE 5) placed under chamfers at the edges of t slots 32. It will be seen from FIGURES 2 and 3 that the hammers 14 a a close tolerance fit betweenthepairs of restraintbars 16 wi their side faces in contact or almost in contact with the bar A minimal clearance is desirable in order to accommodate t aforementioned slight radial movement of the hammers. It wi also be seen that the bars are at a finite distance from t outerendsoftherespectivehammers sothatthedovetail secti heads 30 of the hammers are clear of both plates 18 and ba In operation, the deburrer assembly 10 would be mount

transversely of and jvist under the top plane of a roller table along which cut slabs travel. Clearance is such that, if the roll assembly is rotated at a substantial peripheral speed greater than the speed of travel of the slabs, the hammers 14 strike the depending burr onthebottom forward edge of each slab and break off respective segments of the burr. In FIGURE 3, a slab 8 is shown with its burr 9 about to be struck by a hammer 14 at the top of its orbit. The restraint bar 16 behind the hammer will act to support the hammer against the tangential force on the hammer as it strikes the burr and thus facilitates more certain removal of the burr segment.