Patent GB-901274-A (GB)
Title: Improvements in friction presses for adapting them for the manufacture of flagstones made of two layers of different materials
IPC: B28B3/02
Filed: 1959-10-27
Abstract: 901,274. Pressing slabs. WALCHHUTTER, U. Oct. 27, 1959 [Oct. 29, 1958], No. 36410/59. Class 87(2). A friction press of the type having a screwthreaded spindle carrying a flywheel driven by friction discs is adapted for the moulding of two-layer flagstones by the provision of two charging carriages mounted on the back of the press and adapted alternately to charge a mould located on the bed of the press with two superimposed layers of material prior to the compression of the material in the mould by the press head. As the press head rises after a compression-moulding operation its movement closes contacts 50 and, in consequence, solenoidoperated valves 31, 32 direct pressure fluid to the cylinders 34, 35 of a double piston whereby a plate 23 is elevated and thus, through studs 22, a plate 20 and loose mould bottoms 21 carried by it, so raising the compressed slab out of the mould 19 ready for sideways ejection. As the press head reaches the top of its stroke, contacts 51, 52 are closed, 51 operating a solenoid valve 43 which applies brakes 46, 47 to the press flywheel and 52 closing an electromagnetic clutch which transmits drive from a motor 3, through a crank and gear-train, to move a carriage 1 along a guide 1<SP>1</SP> and so to push the slab out of the machine. A cam 8, rotated from the gear train, then closes contacts 10 which operate the valve 31, to release pressure from the cylinder 34 at which the piston 33 descends, assisted by springs 36, 37, by an amount equal to the thickness of a bottom layer of material which is fed into the mould from the carriage 1, which is then, retracted. Another cam 9 then closes contacts 11 which causes the engagement of an electromagnetic clutch which transmits drive from a motor 4 to advance a carriage 2 along a guide 2<SP>1</SP>. A cam 8<SP>1</SP>, rotated from the motor 4, closes contacts 12 which operate the valve 32 to release pressure from the cylinder 35 at which the piston 33 descends through. the remainder of its stroke, allowing enough depth in the mould for a second layer of material which is fed on to the first layer from the carriage 2. When the carriage 2 is retracted a cam 9<SP>1</SP> closes contacts 13 which operate the valve 43 to release the brakes 46, 47. The contact 13 also closes the circuit of an electromagnet 53 which causes the press to perform the compression operation in known manner. Tubular projections from the guides 1<SP>1</SP>, 2<SP>1</SP>, fit into brackets 14, 15 on the frame, the guides thus being detachable. If a slab composed of only one layer of material is required the guides 1<SP>1</SP>, 2<SP>1</SP> and carriages 1, 2 are removed and another guide, with its carriage, is fitted to a bracket 18 and aligned along the intermediate position indicated by X, Fig. 2. The mould can be positioned accordingly because the studs 22 from the plate 20, which support the mould bottom plates with a stud under each, are fitted in a selection of holes 24-29 in the plate 23. Slabs of various thickness and/or slabs with layers of different thicknesses may be moulded by altering the strokes of the pistons in the cylinders 34, 35.