Numerous structures have been described in the prior art as possible replacements for the conventional structure of a paint brush in which part or all of the structure is sufficiently inexpensive that it can be considered disposable after a single or a relatively few uses. Illustrative structures of this type are described in U.S. Pat. Nos. 2,265,274; 2,514,496; 3,094,729; 3,783,468; 3,874,021; and 4,155,139. No such known structure has become widely used, however, and for the most part the public continues to use conventional paint brushes of the type comprising a plurality of bristles ("bristles" as used herein includes filaments of polymeric material) having base end portions positioned along the sides of an elongate felt center spacer and a tubular ferrule typically of metal that receives the portions of the bristles along the sides of the center spacer in one end portion, has a resin such as epoxy poured into it to bond the bristles and center spacer in place, and then receives a portion of a handle, typically of wood or plastic in its other end portion so that the ferrule fastens the handle to the bristles. Such conventional paint brushes typically require a large amount of hand labor for their assembly, which adds significantly to their cost. Also, many lower cost conventional brushes incorporate polymeric bristles (e.g., polyester or nylon) many of which are made hollow to reduce their cost, and as a result will buckle more easily than solid bristles and will draw paint or other coatings into the bristles by capillary action that will not be removed when the brush is cleaned; and some of which are made with other than circular outer peripheries (e.g., generally triangular or cross like cross sections) to enhance the ability of their end portions to be flagged (i.e., split into smaller fibers) to improve their paint holding and spreading ability, and as a result have longitudinal recesses along their outer surfaces that have a tendency to retain paint when the brush is cleaned. Such retained paint in or on the bristles causes the bristles to loose some of their flexibility so that the brush is not as effective during reuse as it was when it was new.
Other types of brushes are manufactured by techniques such as wrapping the central portions of tufts of bristles around the central portions of staples and driving the staples into a backing member at the bottoms of recesses from one of its surfaces shaped so that walls defining the recesses position the bristles with their distal ends projecting at generally a right angle to the surface; or wrapping the central portions of bristles around a rod along its length and crimping a metal strip to a generally U cross sectional shape around those central portions and rod so that the distal portions of the bristles project in generally the same direction. Like the paint brush structures described above, however, manufacturing such other types of brushes requires working with individual bristles and require backings made from either molded plastics or wood.
USPTO Backgrounds
USPTO Backgrounds