US 3118162 A
Description (OCR text may contain errors)
Jan. '21, 1964 A. KARR ETAL 3,118,162
WIRE BRUSH STABILIZER Filed April 13, 1962 Z4 2 Ml EZZORS BY M United States Patent 3,118,162 WEE BRUSH STALLILIZER Alexander Kart, 52% W. i ieitter St., Stratford, (Iona, and .ioscph 3. lirighindi, 44 Nichols Ava, Fairiield, Conn. Filed Apr. 13, 1962, er. No. 187,386 1 Claim. (*Cl. 15-18%) Our invention relates generally to Wire brushes for removing scale and other objectionable formations which build up on metallic objects, and particularly to a stabilizer for such wire brushes that are well suited for removing scale from the sheets and beads of steam boilers, particularly the portions of sheets and beads which surround the open ends of bofler fire tubes.
Removing scale from the sheets and beads of steam boilers, particularly around the open ends of boiler fire tubes, has been a difficult and time-consuming task, and in view of the fact that it must be done periodically, it is a serious and costly maintenance problem. There are many other environments wherein it is necessary or desirable to remove scale which forms on metallic objects; however, it is particularly a vexing problem in the maintenance of steam boilers wherein beads and sheet portions around the open ends of fire tubes are particularly prone to have scale build up on them. It has heretofore been the practice to remove such build-up scale formations by employing a wire brush attachment for a portable power tool and to abrade away the scale. If the prior technique can be visualized, its shortcomings will become apparent immediately, for it is essential that the workman apply considerable force so as to press the bristles of the wire brush into firm frictional and abrading contact with the scale formation. It is not an easy task to do this while the wire brush is rotating, as there is a tendency for the wire brush to spirally walk away from the area being abraded and for the workman to be maneuvered into an ofi-balanced position, sometimes pivoting him about the wire brush as it moves laterally away from him and causing him to slip and fall. As a result it has been an extremely dificult and time-consuming task for a workman to remove scale formations, particularly about the open ends of boiler fire tubes.
The object of our invention is to eliminate this problem and it is accomplished in one form by providing stabilizing means on wire brush attachments for power tools which functions to properly position the wire brush relative to the scale formation being removed and to prevent its undesired transverse displacement movement relative thereto.
Other objects and further details of that which we believe to be novel and our invention will be clear from the following description and claim taken with the accompanying drawings, wherein:
FIG. 1 is a vertical sectional view taken through an improved wire brush attachment including the stabilizing means of the invention and showing the cooperating chuck portion of a portable power tool in dotted lines;
FIG. 2 is a perspective view of the FIG. 1 attachment on a reduced scale;
FIG. 3 is a view similar to FIG. 2 but showing a stabilized attachment having an alternative type of wire brush;
FIG. 4 is a schematic view showing, respectively, at 4a the prior 'art apparatus for removing scale; at 412 the F168. 1 and 2 attachment arrangement which incorporates the invention for removing scale, and at FIG. 40 the FIG. 3 attachment arrangement, and
FIG. 5 is a somewhat schematic elevational view showing the front sheet of a boiler and the open ends of the fire tubes with scale formed about their beads.
A rapid understanding of a principal environment in 3,ii&l52 Patented Jan. 21, 1964 which the invention is extremely useful may be obtained by referring to FIG. 5. The front sheet of the boiler is designated 8 and it is usually a metallic plate that includes a plurality of openings 0 within which the open outer ends of metallic fire tubes T are rigidly connected, as by welding. In practice there is frequently a circular bead B of welding surrounding the opening 0 which physically secures the tubes to the sheet. The beads B and adjacent portions of the sheet S are subject to the buildup of scale formations SF as a result of the environmental conditions in steam boilers which facilitate oxidation of the nearby metallic elements resulting in the formation of a substantial amount of scale which is undesirable.
With reference to FIG. 4a the prior art means and method of removing the scale will become apparent. A wire brush cleaning attachment WB, which was essentially cup-shaped and included a ringdike formation of wire bristles BR of the approximate diameter of the tube bead to be cleaned, was operatively connected to the chuck of a portable power tool PT by a stub shaft on the attachment. The wire brush bristles were pressed against the scale formation SF by the workman while the wire brush was rotated by the power tool. Assuming clockwise rotation of the wire brush relative to the workman, which is normal, the wire brush of the prior art attachment had a tendency to spiral ofi to the right relative to the workman when he was pressing it against the scale. it is an extremely difficult maneuver for a workman to maintain a rotating circular wire brush in a fixed area while he is pressing it into firm planar contact with a flat surface, as anyone who has even attempted to polish a floor with a single brush floor polisher knows. As a result, it was an extremely diificult and time-consuming task to remove scale with the prior art wire brush attachment.
In order to eliminate the noted deficiency of prior art wire brush attachments for removing scale, we have devised an improved attachment that includes stabilizing means which functions to both properly position the wire brush bristles relative to the scale formation and to maintain it in its proper position during operation. In FIGS. 1 and 2, the preferred form of the invention, wherein a cup-shaped wire brush is employed, is illustrated. The improved stabilized wire brush attachment is designated generally by reference numeral 10 and shown in solid lines in FIGS. 1 and 2. It comprises a shaft 12, a cupshaped wire brush 14, a pair of positioning and locking nuts 16, and a stabilizing member 18.
Shaft 12 is elongated, generally cylindrical, preferably made of case-hardened steel and includes a forward threaded portion fit} at one end for receiving and mounting the stabilizing member 18, an adjacent plain portion 22, a second threaded portion 24 spaced from threaded portion 24} and adjacent to plain portion 22 for mounting the wire brush 14, and an hexagonal portion 26 at its other end for effecting a rotary driving connection between the shaft and the power tool PT. The diameters of portions 2%, 22 and 2dare the same; however, the widest dimension across a cross section of the hexagonal portion 26 is slightly less than the diameter of the other portions.
The cup-shaped wire brush 14- comprises a circular radially extending main body portion 23, which is preferably made of a hard metal, having a central hub as including a threaded circular opening 32 and an axially extending peripheral portion 3 2- at one side thereof. A plurality of stiff wire bristles are disposed to form a ring 36 and have their ends anchored firmly in and about the periphery of the body portion '34. The wire brush 14 may be mounted on the shaft 1 9 by being slipped over the hexagonal shaft portion 26 which, being of lesser diameter than that of the opening 32, which is dimensioned to tightly fit on the threaded shaft PQI'LlOH 24, allows such relative movement, and thereafter threaded onto the threaded shaft portion 24. The pair of internally threaded clamping nuts 16 may be disposed on the threaded shaft portion 24. to straddle the wire brush hub Fill-to both properly position and lock the wire brush in place on the shaft. It will be understood that the clamping nuts 16 are also mounted from the right hand end of the shaft by being slipped over the hexagonal portion 2-6 in the sequence of a nut 16, the wire brush l4 and then the other nut 16; thereafter, they are adjusted to assume a position such as that illustrated in FIG. 1.
The stabilizing member 18 for the wire brush is illustrated as a spherical ball, which is the preferred shape. Ball 13 is preferably made of steel and includes a tapped bore 38 at one side which is arranged to threadedly receive the threaded shaft portion 2% to rigidly, but removably, mount the ball on the shaft. in order to insure a tight connection during operative conditions, the threads of the tapped bore 38 and the shaft portion 2%} are such as to cause tightening of the mounting of the ball on the shaft in operation. Normally, the shaft 12 .will rotate clockwise relative to the workman using it,
and therefore, the threads on the shaft portion 2% should be counter-clockwise and cooperating threads formed in the bore 38, so that rotation of the shaft in operation causes the shaft portion to screw into the bore 33 and tighten the connection.
In FIG. 1, the chuck portion of a power tool PT has been shown in dotted lines, and it will therein be observed that'the hexagonal shaft portion 26 constitutes the means for effecting a rotary drive connection-between the power tool and the wire brush attachment. The details of the chuck connection are not illustrated as they form no specificpart of the invention.
The operation of the FIGS. 1 and 2 stabilized wire brush attachment may be quickly understood from Fl 4b wherein it will be observed that the stabilizing all 18 is disposed within the front end of a boiler tube T which results in the centering, i.e., proper positioning of the wire brush bristles 36 relative to the bead B and the scale formation SF that is to be removed. In operation, rotation of the wire brush attachment in is effected after the stabilizing ball 18 has been inserted through the bead B into the tube T, and thereafter, pressure applied by the workman to cause the wire brush bristles to come into 'firrn frictional and abrading contact with the bead and the scale formed thereat. attachment and removal of the scale may be effected without any'lateraldisplacement of the wire brush relative to the head, as a result of the restraining influence of the ball 18 in thetube. It has been found in practice that the diameter of the stabilizing ball 18 should be smaller than the innerdiameter of the fire tube into which it is disposed, preferably by approximately one-half inch, in order to allow some slight lateral'spiralling play between the wire brush and the head. It has also been found in practice that the interior of the fire tube will not bescored by the stabilizing ball, which in operation rotates within and relative to it, if the ball is kept well lubricated at all times during operation. 1 will also be appreciated by those skilled in the art that diiferent sized stabilizing balls andfwire brush members may be employed for different environments involving fire tubes and beads of differing diameters, so long as the relationships are maintained wherein the stabilizing ball is of smaller diameter than the interior of the fire tube and the ring of wire bristles is substantially the same diameter as the scale formation being removed. In this regard the mounting of the ball 18 on the shaft has been intentionally made detachable topermit mounting of any one of a number of different diameter balls depending upon the diameter of the fire tubes, and the mounting of the wire brush 14 is also'detachable to permit changing. Lastly, it should be realized that though the spherical Rotation of the wire brush 4i ball is the preferred shape for our stabilizing member, other shapes could be employed, such as sections of cylinders with tapered leading ends to facilitate their insertion into fire tubes.
In FIG. 3 we have illustrated a wire brush attachment wherein our invention has been incorporated, but having a different type of wire brush than that illustrated in FEGS. 1 and 2. The entire attachment with the modified wire brush is designed 4-0. Wire brush attachment 49 is constructed in the same manner as the wire brush attachment it} of FIGS. 1 and 2, except that it includes a wire brush 4-2 in the form of a section of a cylinder and having radially outwardly extending wire bristles. 'Iheother elements of the FIG. 3 attachment are the same as those of the FIGS. 1 and 2 embodiment, and therefore, are designated by similar reference .numerms with a prime added.
The Wire brush %2 is particularly well suited to clean the interior'walls oftubes and remove scale that may be formed thereon. Therefore, the diameter of the wire brush 4-2. is selected so as to make frictional abrading contact between the ends of its wire bristles and the inner wall of the fire tube and operates as ilustrated in FIG. 4c. it will there be observed that the cylindrical wire brush 42 as well as the stabilizing ball 1-8 is disposed within the tube T.
It should be realized that in some environments it is desirable to utilize both the FIGS. 1 and 2 and FIG. 3 types of wire brushes to effect scale removal, the cupshaped wire brush 14% being well suited for removing scale formations about a circular bead and the wire brush 42 being well suited for removing scale formations on the inner walls of tubes. Our improved wire brush attachment, in addition to properly stabilizing the attachment, permits interchangeability of wire brushes simply by removing the attachment from the power tool and thereafter sequentially removing the nut 16 adjacent the hexagonal shaft portion 26, and thevwire brush that is mounted on the shaft portion24, and then sequentially placing on the shaft portion 24 the desired type of wire brush and the nut 16 that had been removed, and properly adjusting and tightening the nuts and the replacement wire brush. In practice, it has been found that cleaning time can be reduced by as much as 95% by utilizing the invention when removing scale from boilerfire tubes.
As willibe evident from the foregoing description, certain aspects of our invention are not limited to the particular details of construction of the examples illustrated, and we contemplate that various and other modifications and applications will occur to those skilled in the art. For example, the invention has been described for use in removing scale formations from boiler fire tubes; however, it is well suited to function as a cleaning device in many other environments. It is, therefore, our intention that the appended claim shall cover such modifications and applications as do not depart from the true spirit and scope of our invention.
What we claim as new and desire to secure by Letters Patent of the United States is: V
A device for cleaning the end portions of a boiler fire tube at its juncture with a boiler tube sheet comprising: an elongated rotatable shaft having a male screw thread along at least a portion of its axial length; means for mechanically rotating a first end of said shaft about its longitudinal axis; rigid positioning means detachably mounted at substantially the second end of said shaft, said positioning means having a circular cross section in a plane perpendicular to said axis, and a diameter approximating but less than the inner diameter of said fire tube, and adapted to be inserted into said fire tube; a rotary cup-shaped brush defining a circular opening therein having a female thread engaging the male thread of said shaft and positioned intermediate said first and second ends, said brush having a brushing surface positioned to bear against a plane normal to the axis of rotation of said shaft and make abrasive contact with said fire tube end portions and a portion of said tube sheet adjacent thereto; and means for selectively adjustably positioning said brush along the longitudinal axis of said shaft to vary the distance between said brush and that portion of said positioning means in contact with said fire tube, said brush being fixed to said shaft and rotatable therewith to clean said end portions While stabilized by said positioning means roating within said fire tube.
References ited in the file of this patent UNITED STATES PATENTS 550,099 Detrick Nov. 19, 1895 646,545 Novotny Apr. 3, 1900 1,254,217 Drummond Jan/22, 1918