US 3325846 A
Description (OCR text may contain errors)
June 20, 1967 WIRE BRUSH Filed April 14, 1965 LOW CARBON STEEL (l4 Mn) DRAW TO GREATER THAN .070
CARBUR/ZE D T0 1.0 T0 l.5 CARBON FIG. 2
DRAW TO .0/6" T0 .070"
FORM BRUSH CARBON L25 IOO 20.0 30.0
% MANGANESE NORMAN P. 6088 FIG. 3
I NVEN TOR.
United States Patent 3,325,846 WIRE BRUSH Norman P. Goss, Mentor, Ohio, assignor to The Anderson Corporation, Worcester, Mass., a corporation of Massachusetts Filed Apr. 14, 1965, Ser. No. 448,210 1 Claim. (Cl. 15179) This invention relates to a wire brush and, more particularly, to an article arranged to finish metallic workpieces by the brushing process.
Modern industrial technology requires the use of wire brushes of various configurations. Such wire brushes can be either fixedly mounted in relationship to the workpiece, or positively actuated by means of rotation, oscillation or the like. The present invention Would appropriately apply to either the stationary wire brushes or to the positively actuated ones, but it is particularly advantageous in the positively actuated wire brushes because of the larger potential for that type of wire brush. Although it has been common practice to finish workpieces by use of a rapidlyrotating wire brush, to a great extent, this procedure has been limited to low rates of stock removal. Although it is possible to obtain wire brushes which will operate for an economic length of time, if the individual strands of wire are of a small diameter, say, below .015 inch, it is much more diflicult economically to produce a satisfactory brush where the individual wire strands are larger than .015 inch and as large as .070 inch. When brushes are made with these larger diameters of steel Wire, they suffer greatly from fatigue; that is to say, the constant elastic bending to which the individual strands of a machine wire brush are subjected causes them to fail rather quickly, particularly at the point where the strand is locked to the hub of the wheel. Because of the difliculty of making long-lasting brushes from larger sizes of wire, it has been necessary to restrict practical brushing operations to low rates of stock removal. All of the current maufacturers of wire brushes endeavor, because of necessity, to use brush wire which is as tough as possible. In other words, they recognize the need for a wire with a high fatigue life. Unfortunately, to attain such wire, the hardness invariably has to be sacrificed. Because of this sacrifice, the wire in the conventional brushes, as presently manufactured, has either a high fatigue life with relatively soft ends, or a high degree of hardness with a short fatigue life. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide a wire brush whose cost is low but whose ability to maintain long life under heavy-duty operation is high.
Another object of this invention is the provision of a Wire brush which has individual strands greater than .015 inch in diameter but which, nevertheless, is capable of extremely long life.
A further object of the present invention is the provision of a wire brush capable of heavy-duty operation in which the individual strands are extremely malleable and have a high resistance to fatigue but which, at the same time, work harden at the ends to cause abrasive resistance, fracturing, and good cutting action.
It is another object of the instant invention to provide a wire brush which may be formed inexpensively from larger sizes of wire and which is capable of a long life of useful service with a minimum of care.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claim appended hereto.
The character of the invention, however, may be best understood by reference to one of its structural forms as illustrated by the accompanying drawings in which:
FIG. 1 is a perspective view of a wire wheel embodying the principles of the present invention,
FIG. 2 is a chart showing the method by which the present brush is formed, and
FIG. 3 is a chart showing the major components of the steel used in the present invention.
Referring to FIG. 1, which best shows the general features of the invention, it can be seen that the wire brush, indicated generally by the reference numeral 10, is composed of a base such as a hub 11 and wire strands 12. The hub 11 consists of a short, tubular main body 13 from either end of which extend radial flanges 14. These flanges clamp around the inner ends of the wire strands 12 and hold them in fixed relationship to the main body 13. The hub 11 is adapted to be fastened to a spindle of a machine tool, which spindle is rotated while workpieces are brought into contact with the outer ends of the strands 12. These strands, because of their sharp cutting edges, perform a machining operation on the workpiece. In general, such operations include the removal of sharp edges and burrs from the workpieces but, in some instances, the brush may be used to produce a finished surface in a man ner similar to that produced by an abrasive wheel.
In the preferred embodiment, each of the strands 12 has a circular cross-section with a diameter in the range from 0.016 to 0.070 inch. Each strand is formed from steel having high malleability and having a high ability to work harden, so that, as the brush is used, the free ends work harden and fracture to give a good cutting ability, since sharp, new cutting edges are continuously being disclosed to the workpiece. Cutting is improved without appreciable loss of fatigue strength. Basically, each wire strand is formed from steel having manganese in the range from 10% to 20% but, in the preferred embodiment, this amount of manganese is 14%. Furthermore, the carbon content is in the range from 1.0% to 1.5% which means that the steel is of the austenitic type.
Referring to FIG. 2, it can be seen that the manufacture of the wire takes place by starting with an ingot of a low carbon steel having 14% manganese. The ingot is rolled to a rod and the rod drawn to a wire. This wire is passed through a wire-drawin g machine to reduce its diameter. In most cases, this would be done starting with No. 5 steel rod and the diameter would be reduced in a number of drawing passes in the wire-drawing machine to a dimension somewhat greater than .070 inch. Then, the wire is removed from the wire-drawing machine and placed in a carburizing furnace at a temperature of 1800 F. to increase the carbon to a content in the range from 1.0% to 1.5 and, at the same time, subjecting the wire to an annealing operation. The wire is quenched in water. The cooling rate should be that which gives the softest condition to the wire, the smallest grain size, and the most uniform carbon distribution.
Then, the wire is drawn to its finished size in the range from .010 inch. to .070 inch. The amount of manganese originally selected must be sufi'icient in relationship to the percentage of carbon to assure that the steel remains austenitic and does not become ferritic. A wire made in this manner has the characteristic of high resistance to fatigue; that is to say, it may be subjected to reversed bending many times Without premature failure; it is malleable and ductile. At the same time, this wire has the advantage that it can work-harden easily at the working tip which, in the wire brush field, means that the ends of the wire will become hard and will fracture, leaving ragged sharp edges to contact the workpiece, thus producing a high rate of cutting without appreciable loss of fatigue strength. 0n the other hand, the main body of the Wire strand 12 of the brush remains ductile and malleable and Will not break, so that the brush is capable of extremely long life.
In FIG. 3 it can be seen that the range of carbon to produce the above characteristics is from 1.0% to 1.5 At the same time, the manganese in the preferred embodiment is in the area of 14% but may range from 10.0% to 20% by weight of the steel.
The method of forming the wire, illustrated in FIG. 2, is particularly inexpensive and permits a high amount of reduction as it passes through each of the dies of the wire-drawing machine. It means that the wire does not have to be removed and annealed between each reduction. By using this process, it is possible to draw the wire down in its very ductile form and, then, by carburizing it before the final sizing reduction to assure that a wire of the proper carbon and manganese content is obtained. This would be a very inexpensive method of making the wire because of the few handling steps and less annealing and wire drawing operations, so that the wire itself would not be costly and the ultimate cost of the wire brush would be in the practical range, from the economic point of view. Nevertheless, the brush made in the manner described above from the wire will have extremely long life, will be as inexpensive as wires of much smaller strand diameter, and will be capable, at the same time, of very heavy cutting operations because of the extremely large size of the wire strand. Each wire strand acts as an individual cutting tool and its ability to operate as a tool and to cut into the workpiece is in direct proportion to the difficulty of bending the wire, this stiifness increasing with the diameter of the wire. It will be understood, of course, that the wire need not, necessarily, be circular in cross-section but be made of any of the various shapes commonly used in wire brushes. An example of a wire which has been produced by the method described above and has been used in the construction of a wire brush has a chemical composition as follows:
Percent Carbon 1.00 to 1.50 Manganese 10.00 to 20.00 Phosphorous, maximum 0.06 Sulphur 0.01 to 0.03 Silicon 0.10 to 0.04
Such a steel has mechanical properties in tension of a yield strength from 55,000 to 75,000 p.s.i., an ultimate strength of 135,000 to 165,000 p.s.i., and a percent elongation into inches of 35 to It normally would have a hardness of 90 to 97% in the Rockwell B scale, but when work-hardened at the lip of the wire as part of a brush would have a hardness of 55 to in the Rockwell C scale. It would have a Charpy V-notch impact of to foot pounds.
It is obvious that minor changes may he made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.
The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:
A wire brush, comprising (a) a 'base adapted to be held in a machine and rotated, and
(b) a plurality of wire strands all held at one end in the base and adapted to be rotated with it with the free ends in contact with a workpiece, each strand having a diameter in the range from .016 inch to .070 inch, each strand being formed from steel having manganese in the range from 10% to 15% and having carbon in the range from 1.0% to 1.5% so that it has good fatigue properties while having good work-hardening properties, so that, as the brush is used, the free ends will work-harden and fracture to give good cutting properties while the remainder of the strand will not break.
References Cited UNITED STATES PATENTS 3,090,061 5/1963 Charvat l5179 X CHARLES A. WILLMUTH, Primary Examiner.
PETER FELDMAN, Assistant Examiner.