GB550229A - Improvements in or relating to the manufacture of brushes - Google Patents

Abstract

550,229. Moulding brushes. HOOVER, Ltd. June 26, 1941, No. 8032. Convention date, Aug. 29, 1940. [Class 87 (ii)] [Also in Group XXIII] In making a brush comprised of bristles of a synthetic organic compound, particularly of nylon, moulded and fused into a thermoplastic back, particularly one containing polymerized vinyl acetate and polymerized vinyl chloride, the bristles are fed from a hopper 25, Fig. 4, by a notch 28 in a reciprocating separator 26, 27 to a position over a loading core 16, into which they are forced by a plunger 30 so that their looped ends project below the base of the core. This loaded core is inserted in the movable member 15, Fig. 2, of a two part core with the bristles projecting into a cavity 18 in a stationary core member 14, and the thermoplastic material is forced into this cavity through a feeding orifice 19 from an injection nozzle 20 of a cylinder 21, into the rear portion of which the material is fed in pellet form 24 from a hopper 22. The forward end of the cylinder is provided with a heating chamber 23. Cooling fluid is circulated through passages 17 in the mould, causing the material to set rapidly around the ends of the bristles. The mould is then opened, the brush removed and the flash or sprue at the back of the brush cut off. In an alternative method, a number of filaments of the synthetic organic compound are brought together to form a continuous strand which may be wound on a drum, and the end of each strand is fused so that the strands can be readily threaded into the seats in the movable mould member without using a loading core. The operation then proceeds as before, the mould members being finally separated a sufficient distance to allow the bristles to be cut off to form the brush, leaving a small amount of the strands projecting from the mould member ready for the next operation.