METHOD OF SECURING BRISTLE BUNCHES IN A THERMOPLASTIC HOLDER

• Main Author: DIRKSING ROBERT S
• Format: Patent
• Language: English
• Published: 31.01.1997
• Edition: 6
• Subjects: BRUSHES; BRUSHWARE; HUMAN NECESSITIES; MANUFACTURE OF BRUSHES

An improved method for fastening thermoplastic bristle tufts to a thermoplastic bristle carrier. The bristle carrier includes premolded holes with outwardly extending generally concentric collars to receive the bristle tufts. The bristles in each of the tufts to be secured to the carrier have their fastening ends melted and fused together to form a thickened fastening end portion. The thickened fastening end portion of each tuft has a cross-section which is no greater than the corresponding cross-section of the premolded hole and outwardly extending collar on the carrier. The premolded collars and the adjacent side wall portions of the premolded holes in the carrier are softened by non-contact heating means, the thickened fastening end portions of the bristle tufts are inserted into the premolded holes and their associated collars substantially without interference therebetween, and the softened collars are swaged about the thickened fastening end portions of the bristle tufts, thereby securing the bristle tufts to the carrier when the swaged collars cool and harden. Because the collars comprise only a small amount of thermoplastic material, heating and cooling requirements to effect joinder are minimized, thereby reducing the overall cycle time for the present process. In addition, the small amount of localized heating in the collars avoids unsightly damage to or distortion of the carrier.