623,534. Joining metal sheets. FUEL FURNACES, Ltd., and PLATT, G. W. Aug. 9, 1947, No. 31953/48. Divided out of 623,031. [Class 20(ii)] [Also in Group XII] A furnace is enclosed in brick or similar material covered by metal sheets fixed along each side by external buckstays in alignment with the lateral edges of two adjoining sheets, a plurality of bolts having their heads embedded in the brickwork and their stems extending through and beyond each buckstay to engage anchor strips abutting the face of the buckstay remote from the brickwork, a fixing nut being screwed on to each bolt so that the edges of the sheets which extend between the bolt heads and the buckstays are tightly gripped. The buckstays 5 may be in the form of two channel section members 12 with bases spaced parallel to one another so that the bolts 7 may pass between them. Anchor strips 15 abut against the outer flanges of the channel pieces 12 and engage the bolts 7. The buckstays are secured in place by nuts 16 screwed over the ends of the bolts 7 so that the sheets are gripped between the inner flanges of the channel members 12 and the embedded bolt heads 6. Each buckstay 5 may be made in two parts, a shorter lower part firmly secured in the ground to which an upper part extending the height of the brickwork is detachably secured by cleats 13 or like means. Specification 623,031 is referred to.