Abstract: A method of making an expanded plastics foam block section and uniting it with a prior made, or partly made, section comprising the steps of charging a mould space of which one end is defined by a surface of the prior section with expandable plastics beads, initiating the expansion and fusion of the beads to create a cohesive but largely unexpanded mass of beads, obtruding the prior section into the mould space to compress a zone of the cohesive mass adjacent to the said one end, increasing the temperature and pressure in the mould space to complete the expansion and fusion process and to compress the end zone of the prior section to bring its end substantially to its unobtruded position, lowering said pressure and temperature, and ejecting the newly made block section from the mould space.Apparatus for performing the method is also disclosed.

Abstract: Plastics foam scrap is drawn by an air stream through a three-stage disintegrating apparatus. Each stage includes a plurality of moving interdigitating pins and the pin spacing and a passage dimension of each stage decreases from stage to stage thereby reducing the material to its component beads.

Abstract: This invention relates to gang saws and other cutting apparatus having oscillating cutters for cutting workpieces into slices. The invention provides apparatus, having two elongate spaced apart cutter supports which are driven to oscillate 180.degree. out of phase with each other. Two sets of cutters are connected to the supports. For a suitable workpiece the cutters may be of a hot wire type. Each cutter of one set is connected to the first support by a resiliently extensible connector such as a spring and to the second support by a non-extensible connection. Each cutter of the other set is connected to the second support by a resiliently extensible connector and to the first support by a non extensible connection. Desirably the cutters of one set alternate with cutters of the other and all cutters are coplanar. Movement of cutters of each set in opposite directions tends to cancel the local influence of cutters on the workpiece.

Abstract: Apparatus for cutting a body of rigid plastics foam material, such as polyurethane or poly-isocyanurate, comprises a bed for supporting the body and two sets of parallel cutting elements adapted to oscillate longitudinally out of phase with each other. The cutting elements may consist of helically twisted ribbons of electrical resistance alloy, twisted in such a way that the handedness of the twist varies at regular intervals along each element. The elements are heated to a temperature below the fusion temperature of the plastics material, and are passed through the body to sever it into a number of slabs.

Abstract: Apparatus for cutting rolls of sheet material is provided with a pair of longitudinally stationary parallel knife blades positioned on opposite sides of a band saw blade which moves longitudinally to remove swarf from between the knife blades. The knife blades are supported on a blade carried band which is held under tension between spaced apart points on a mounting frame. A longitudinal gap in the knife blade exposes a section of the band saw blade to cut the core of a roll of sheet material.