Patent ID: 6578927
Filing Date: 2003-06-17
Classification: A46D,B29C

Abstract:
A method of producing brush products whose brush bodies are injection molded from plastic, comprising the steps of:providing an injection molding tool comprising a base plate that supports a pair of split bottom plates, the pair of split bottom plates each including a plurality of bores and comprising an upper plate and a lower plate which can be displaced relative to one another, the injection molding tool further comprising an intermediate plate and the base plate with the pair of split bottom plates cooperatively define a portion of a mold interior; providing a severing device comprising a flat knife that swings back and forth and which acts without a counter part blade, the severing device being incorporated as a component of the injection molding tool and being displaceable In a direction transverse to the back and forth swinging thereof; introducing a plurality of endless cords of bristles into the bores of the bottom plates and into the mold interior; injection, in a first injection stage, a plastic material into the mold interior such that the bores of the bottom plates as well as the portion of the cords of bristles extending into the mold interior are sealed, the first injection stage does not fulfill the mold interior; in a plurality of further injection stages, filling the mold interior with a plastic material, the further injection stages being differentiated in terms of pressure, speed and volume; after the conclusion of the final injection stage, displacing the intermediate plate relative to the base plate and bottom plates to an opening position after which the cords of bristles are clamped by the bottom plates, in the opening position the brush body is firmly held and the cords of bristles are rigidly tensed between the brush body and the upper one of the pair of split bottom plates; and wherein a cutting operation is subsequently performed by the severing device by displacing the flat knife along a sectional plane between the brush body and the upper one of the split bottom plates and swinging the flat blade back and forth in a direction transverse to the direction of displacement, the cutting operation being aided by a tension of the cords of bristles and an internal rigidity of the individual filaments thereof.