Patent GB-1098357-A (GB)
Title: Brush construction
IPC: A46D1/00
Filed: 1964-12-16
Abstract: 1,098,357. Brushes. J. C. LEWIS and G. SHAW. Dec. 16, 1964 [Dec. 16, 1963], No. 51271/64. Heading A4K. In a brush construction comprising thermoplastic brush fibres which have different cross-sectional areas along their lengths and which also may have different cross-sectional shapes along their lengths, the fibres each comprise a stem zone and, at least at one end of the stem zone, an abrasion-resistant zone, the stem zone having a minimum cross-sectional area less than the average cross-sectional area of the or each abrasion-resistant zone. The average weight per unit length of the or each abrasion-resistant zone preferably is at least 10% greater than the average weight per unit length of the stem zone. The fibre may have either a single abrasion-resistant zone or two abrasion-resistant zones joined by a common stem. The or each abrasion-resistant zone may comprise multiple working tips, for example to give a bifurcated fibre or a fibre generally of trident shape in which each side arm is itself also trident-shaped thereby to give a fibre having seven working tips. The stem zone may be waved or crimped; such waving or crimping may be effected either in one plane or in two planes. Either one or both of the stem zone and the or each abrasion-resistant zone may be of uniform cross-sectional area and of uniform crosssectional shape along the length of the zone or zones. Either one or both of the stem zone and the or each abrasion-resistant zone may be of circular cross-section at every point along the zone or zones. Alternatively, either one or both of the stem zone and the or each abrasion-resistant zone may comprise interconnected webs, the ratio of web length to web thickness in the stem zone preferably being at least 4:1; such webs may give a zone or zones having a Y-shaped cross-section. The or each abrasion-resistant zone may be of non-uniform cross-sectional area and/or of non-uniform cross-sectional shape along the length of the zone or zones; the or each abrasion-resistant zone may be tapered. If the fibre comprises two abrasionresistant zones, such zones may be the same or different. Fibres suitable for use in brush constructions include: (a) a fibre of circular cross-section at every point along its length and comprising an abrasionresistant zone of uniform cross-sectional area joined by a stem zone to a tapered abrasion-resistant zone; (b) a fibre in which the cross-sectional shape changes from being circular at the free end of the abrasion-resistant zone to being Y-shaped at the end of the abrasion-resistant zone adjacent the stem zone which is of Y-shaped cross-section; and (c) a fibre in which the "free" end of the stem zone of a fibre (b) is integrally joined to the "free" end of the stem zone of a fibre having circular cross-section and uniform cross-sectional area along the lengths of its stem zone and abrasion-resistant zone. Examples of fibres of suitable shape are illustrated in Figs. 1 to 14 (not shown). A plurality of fibres, each of which has two abrasion-resistant zones joined by a common stem, may be interconnected between their stems by a common segment so that the fibres are held in a parallel spaced relationship; as illustrated in Fig. 17, after bending the fibres about the segment so that the two abrasion-resistant zones of a fibre are adjacent each other, the resulting arrangement may be retained by wire 15 in metal channel 16 to give a strip-type brush. As illustrated in Fig. 22, a plurality of fibres, each of which has a single abrasion-resistant zone, may be interconnected between their stems by a common segment so that the fibres 21 are held in a uniformly spaced relationship; after placing adjacent each other a plurality of such arrangements, see Fig. 24, the brush construction of Fig. 26 is given by placing cap 24 and attached handle 27 over the common segments 22, 22<SP>1</SP> and 22<SP>11</SP>, the assembly being made secure by rivets 26 passing through holes formed in the cap in alignment with holes 23, 23<SP>1</SP> and 23<SP>11</SP> formed in the common segments. When the fibres each have a single abrasion-resistant zone, the common interconnecting segment alternatively may be circular; as illustrated in Fig. 28, a plurality of arrangements each comprising an annular segment 29 may be mounted on shaft 31 and key 32 to provide a cylindrical or rotary brush. The fibres may be made by moulding, preferably by injection moulding; the fibres may be made from a polyolefinic, for example polypropylene or a copolymer of ethylene and propylene, or polyamide material which may include colorants, extenders, plasticizers and modifiers.