# US 5,701,629 A · Hollow brush bristle with radiating spokes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,701,629 A - Document ID: US5701629A - Status: Granted - Kind: A - Application number: 08/504,114 - Filed: 1995-07-19 - Granted: 1997-12-30 - Earliest claimed: 1995-07-19 - Assignees: Speciality Filaments, Inc. - Inventors: Timothy D. O'Brien - Web page: https://patentgrep.com/patent/US5701629A ## CPC - A46D 1/0238: {Bristles with non-round cross-section} - A46D 1/00: Bristles; Selection of materials for bristles (making artificial bristles D01D, D01F) - A46D 1/0246: {Hollow bristles} - A46B 2200/202: Applicator paint brush - Y10T 428/2973: Particular cross section - Y10T 428/2975: Tubular or cellular - A46D: MANUFACTURE OF BRUSHES - A46B: BRUSHES (handles not integral with brushware B25G) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A polymer bristle (100) for a liquid-applying brush such as a paint brush includes in cross section a central bore (95), an annulus (96) and preferably three radiating spokes (97) with parallel sides and rounded tips. The bristle is tapered from a thick end (101) that is bundled into the ferrule of a brush toward a thin end (103). The bristle may be flagged by slits (130). ## Claims ### Claim 1 A brush bristle for an applicator brush, the brush bristle being formed of a polymer and being straight, having a denier of 32-2500 and having a length and a cross section taken across the length, the cross section comprising: a generally circular central bore having a bore radius; an annulus having an outer radius, said annulus surrounding the central bore; and a plurality of spokes extending outwardly from the annulus, each of said spokes including two substantially parallel sides and a rounded tip distal the annulus; wherein the polymer is substantially oriented in a lengthwise direction, whereby the bristle is optionally flagged at an applicating end thereof; and wherein each of the spokes extends from the annulus a distance substantially equal to or greater than the bore radius and no greater than the outer radius of said annulus. ### Claim 2 (depends on 1) The bristle according to claim 1, wherein said plurality of spokes consists of exactly three spokes. ### Claim 3 (depends on 1) The bristle according to claim 1, wherein the polymer is polyester or nylon. ### Claim 4 A brush bristle for an applicator brush, the brush bristle being formed of a polymer and being straight, having a denier of 32-2500 and having a length and a cross section taken across the length, the cross section comprising: a generally circular central bore; an annulus surrounding the central bore; a plurality of spokes extending outwardly from the annulus, each of said spokes including two substantially parallel sides and a rounded tip distal the annulus; wherein the polymer is substantially oriented in a lengthwise direction, whereby the bristle is optionally flagged at an applicating end thereof; and wherein the bristle is tapered. ### Claim 5 (depends on 4) The brush bristle according to claim 4, wherein said plurality of spokes consists of exactly three spokes. ### Claim 6 (depends on 4) The brush bristle according to claim 4, wherein the polymer is polyester or nylon. ### Claim 7 A brush bristle for an applicator brush, the brush bristle being formed of a polymer and being straight, having a denier of 32-2500 and having a length and a cross section taken across the length, the cross section comprising: a generally circular central bore; an annulus having surrounding the central bore; a plurality of spokes extending outwardly from the annulus, each of said spokes including two substantially parallel sides and a rounded tip distal the annulus, and wherein an applicating end thereof is flagged. ### Claim 8 (depends on 7) The brush bristle according to claim 7, wherein said plurality of spokes consists of exactly three spokes. ### Claim 9 (depends on 7) The brush bristle according to claim 7, wherein the polymer is polyester or nylon. ### Claim 10 An applicator brush comprising: a plurality of brush bristles formed of a polymer each having a ferrule end and an applicating end; means for holding the plurality of brush bristles in a bundle; and means for manipulating the bundle; at least 15% of the plurality of bristles being straight, having a denier of 32-2500 and a length and a cross section taken across the length, the cross section further comprising: a generally circular central bore; an annulus surrounding the central bore; and a plurality of spokes extending outwardly from the annulus, each of the spokes including two substantially parallel sides and a rounded tip distal the annulus; wherein the polymer is substantially oriented in a lengthwise direction in at least a region of the brush bristle adjacent to an applicating end thereof, whereby the brush bristle optionally is flagged at the applicating end, and wherein said brush bristles are mutually spaced apart in the bundle by the spokes, such that the brush holds an increased quantity of material to be applied. ### Claim 11 (depends on 10) The brush according to claim 10, wherein the plurality of spokes consists of exactly three spokes. ### Claim 12 (depends on 10) The brush according to claim 10, wherein the bore has a bore radius and each of the spokes extends from the annulus a distance substantially equal to or greater than the bore radius and no greater than the radius of the annulus. ### Claim 13 (depends on 10) The brush according to claim 10, wherein the polymer is polyester or nylon. ### Claim 14 (depends on 10) The brush according to claim 10, wherein the bristles are tapered, with the ferrule end being larger than the applicating end. ### Claim 15 (depends on 10) The brush according to claim 10, wherein the applicating ends of said bristles are flagged. ### Claim 16 In a plurality of monofilamentary brush bristles for association together to form an applicator brush, each bristle being straight and formed of a thermoplastic polymeric material, the improvement wherein: each bristle has a substantially circular cross-section with an outer wall and an inner wall defining an internal hollow bore extending therethrough along the entire length thereof, and three spokes extending outwardly from and spaced 120.degree. about said outer wall, each spoke being substantially rectangular with rounded distal corners, and each spoke having a height at least equal to the bore radius and no greater than the radius to said outer wall; said spokes constituting means for spacing said bristles in mutually spaced apart position such that in brush form, said bristles hold an increase quantity of material to be applied; and said bristles having a denier of 32-2500. ### Claim 17 (depends on 16) Brush bristles according to claim 16 which are tapered, and each of which has a minimum outer diameter at its narrow end of about 4 mils and a maximum outer diameter at its large end of about 20 mils. ### Claim 18 (depends on 16) Brush bristles according to claim 16 wherein said thermoplastic polymeric material is selected from the group consisting of polyester and nylon. ### Claim 19 (depends on 16) Brush bristles according to claim 16 which are flagged at one end thereof. ### Claim 20 (depends on 16) In a brush comprising a handle and a plurality of bristles extending from said handle, the improvement wherein said brush bristles consist of at least 15% of the bristles according to claim 16.