Arrangement in mill drums provided with wear protective linings

#The present invention relates to an arrangement in mill drums provided with wear protective linings and ore lifting and carrying means, said means having the form of wings comprising an elastomeric material and extending radially inwardly from the lining of the mill drum, each of said wings being anchored to the wall of the mill drum by means of securing means which at any desired pitch along the said wings penetrate into the material of the base of the wings, wherein they are retained by anchoring means extending in the longitudinal direction of the bases of the wings.

#The wear protective linings of mill drums for the grinding of ores and similar materials were previously predominently made of metal, metal alloys etc. Gradally, however, the composition of such linings has changed from a primarily metallic nature to an elastomeric nature, such as linings made chiefly of rubber and synthetic resins of varying hardness and elasticity. In order to increase the capacity of such mill drums, i.e. the throughput or the quantity of material ground per unit of time, such mill drums are now frequently provided with elongate projections ususally in the form of wings which extend from the lining radially in toward the centre of the mill drum and which are arranged upon rotation of the drum to lift the ore to a certain height above the bottom of the drum and to cause said ore to fall continuously onto said bottom.

#Mill drums hitherto known for this purpose have relatively moderate dimensions especially with respect to their diameter. Furtherore, because, inter alia, the wings are placed under considerable stress as a result of the torque to which they are subjected as they carry and lift the ore during rotation of the drum, and because of the strain to which the devices securing the wings to the drum are subjected, it has been necessary to limit the extension of the wings beyond the lateral lining plates to a radial dimension which, expressed in general terms, is substantially the thickness of said lining plates, i.e. in practice 40-100 mm.

#So that the invention will be more readily understood and further features they make apparent, embodiments will now be described with reference to the accompanying drawing, in which

#FIG. 1 is a sectional view of a portion of a mill drum provided with a wear protective coating in accordance with the invention;

#FIG. 2, is a view along the surface of its longitudinal edge, the root or base end of a wing of elastomeric material serving as a lifting means for ore or the like to be ground in the mill drum, as well as coordinated short retaining rails fitted with yoke means in a separate view;

#Referring firstly to FIG. 1 of the drawing, reference numeral 10 designates either a peripheral portion of a mill drum or the end-wall thereof lined for autogenous or semiautogeneous grinding in accordance with the invention. Reference numeral 11 designates two adjacent plates in the protective lining of the mill drum, which plates rest against the cylindrical wall or end wall. Reference number 12 designates a wing which comprises an elastomeric or resilient material and which extends radially inwardly from the lining of the mill drum. The plates can be made of any material suitable or preferred for the purpose e.g. a metallic and/or elastomeric material. The plates 11 and the wings 12 alternately cover the inner surface of the mill drum and together actually constitute the lining of the mill drum.

#In FIG. 3, reference numeral 13 designates two substantially parallel holes made in the longitudinal direction through the root or base of the wing, intended to receive and accommodate anchoring rods inserted in them. These rod holes can, in accordance with the invention, either be produced by mechanical processing of the wings or by a moulding process in the original manufacturing of the wings and/or by plastic deformation of wing blanks. Reference numeral 14 designates e.g. in FIG. 1 one of a number of yoke means which are characteristic of the invention, said yoke means being directed transversely to the longitudinal direction of the wings and accommodated in the root or base of the wings. Each yoke means 14 is provided with at least two symmetrically arranged rod holes, designated by 15, the distance between which is selected such that said holes in the assembled position illustrated in FIG. 1 coincide with the rod holes 13 (FIG. 3) in the base of the wing. Reference numeral 16 in the example shown in FIG. 1 designates two oblong anchorage rods inserted or forced into the holes 13, which rods also penetrate each one of the rod holes 15 in both of the arms or shanks of all of the yoke means 14. Although FIG. 3, shows a wing having a base which is penetrated longitudinal by only two rod holes 13, the number of rod holes in accordance with the invention can, however, be greater depending on specific design requirements. Characteristic of all variants or modifications is, however, that the number of rod holes 13 in the base or attachment part of each wing 12 corresponds with the number of rod holes 15 in each yoke means 14 so that the various rod holes coincide with each other in order to enable the corresponding anchorage rods to pass through at least certain ones of all the rod holes.

#Reference numeral 17 in FIGS. 1, 2, 3 and 8 designates narrow transverse recesses made in the base of the wings to receive and accommodate the yoke means 14. The recesses 17 extend inwards in the material of the wings from the limiting surface of the longitudinal edge in the retaining or base part of the wing and penetrate the walls of the rod holes 13 at a desired, preferably even pitch, along the wing and allow the yoke means 14 to be inserted in their correct position in the base of the wing so that their rod holes 15 coincide with the rod holes 13 of the base of the wing. Thus, in the base of each wing there is entered and accommodated in position a predetermined nuber of yoke means 14 after which the anchorage rods 16 are inserted through all of the rod holes 13 and 15.