Abrading – Frame or mount – Portable abrader
Reexamination Certificate
1999-02-16
2001-10-09
Morgan, Eileen P. (Department: 3723)
Abrading
Frame or mount
Portable abrader
C110S194000, C110S304000, C110S219000, C110S219000, C110S348000
Reexamination Certificate
active
06299518
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates generally to the field of devices for deburring and cleaning metallic structures. More particularly, the present invention relates to a device for providing surface preparation for metallic structures such as piping and tubing. More particular yet, the present invention involves an attachment for a rotary power tool, where the attachment is a rotary abrasion device that cleans the outside of the end of a pipe or tube in preparation for soldering or welding procedures. As well, the rotary abrasion device can be utilized for inner-surface preparation—e.g., reaming and cleaning the inside of the same end of piping and tubing.
2. Description of Prior-art
While the general field of metalworking with piping and tubing involves problems associated with removal of oxide build-up and surface irregularities (e.g., burrs, nicks, cuts), the more specific field of pipefitting will be discussed. It should be noted that this discussion is limited to the specific field of pipefitting for the sole purpose of illustrative clarity and is not meant to limit the intended scope of the invention.
In the field of pipefitting, the general operation for soldering pipes together begins with the process of cutting a pipe to length. Typically, pipe cutters are used. These cutters are well known in the art and are generally C-shaped and include a cutting wheel at one end and bearings at the other end. The pipe is positioned within the cutter between the cutter's ends and tightened so that the cutting wheel and the bearings come into contact with the outer surface of the pipe. The cutter is then rotated around the pipe while the cutter is increasingly tightened. The cutting wheel cuts deeper into the piping with each turn of the cutter. This process continues until the piping is eventually cut through where the cutting wheel made contact. This common cutting process yields at least two undesirable effects.
Cutting pipes in the field of pipefitting creates undesirable metal burrs along the inner surface at the cut edge of the pipe, and slightly decreases the diameter of the pipe at the cut edge. Any such irregularities in the pipe can affect the flow of whatever fluid (e.g., refrigerants, water, . . . etc.) is used within the finished system (e.g., HVAC, hot water heater plumbing, heat pump system, . . . etc.). Additionally, metal burrs that are not removed can break off and foul any machinery and apparatus (e.g., pumps, sensors, heating elements, . . . etc.) that are incorporated into the finished system. In addition to the problems related to the piping's inner surfaces, exposed surfaces of metallic piping are often subject to oxidation. This is particularly acute with respect to copper piping where the oxides that naturally form on the pipe's outer surface must be removed to enable a secure fit and weld. It is common that using a pipe cutter also reduces the diameter of the pipe at the very end and may leave excess material (i.e., burrs) on the edges of the cut. If not properly removed, any subsequent weld will be weak and subject to increased chance of leakage. Further, excess material such as copper filings and burrs within a domestic hot water heating system can encourage undesirable calcifications within the pipes requiring costly repair or replacement of pipes.
In operation after the pipe has been cut to length, a pipefitter will typically use a manual reamer to cut away burrs from the cut edge and to widen the mouth of the pipe opening back to its original diameter. This includes preparation of the inner surface of the piece having the wider diameter as well as the outer surface of the piece to be soldered or brazed thereon. The preparation of the surfaces typically involves abrading the surfaces to be joined with an abrasive means. Conventionally, this is accomplished manually using either sandpaper of a suitable rugosity for metal or hand-held wire bristles. Such manual brushes are typically worn and misshapen beyond repair after extended use and then become unwanted trash. After the outer and inner surfaces near the cut edge of the pipe are manually provided with an oxide-free, shiny appearance, the pipefitter applies flux or a similar solder-drawing compound onto the cleaned portions of tubing to be soldered and pushes one into the other. Heat is then applied and followed by solder. The workpiece is cooled so as to allow the drawn-in solder to harden and form a fluid tight joint.
From the operation described above, it becomes critically apparent that proper surface preparation occurs prior to the soldering or brazing. This includes the requirements that the cut end of the pipe be restored to its full diameter, the exposed surfaces be free from any oxidation, and that any excess material or burrs along the cut must be removed. In the past, the widening has been accomplished by the separate step of reaming the cut end on its inner surface with a reaming tool while the removal of any burrs and oxidation was accomplished via sandpaper or some wire bristles. Among the prior-art references, several known devices typify the aforementioned pipe preparation tools and some attempt to alleviate the problems associated with manual reaming and deburring. However, none of these below patents touch the disclosure of this invention as described herein.
The device of U.S. Pat. No. 5,168,660 issued to Smith is an attachment for an existing drill that includes two or three brushes. The brushes are spring-biased to press against a pipe upon insertion. However, this device is entirely lacking any pipe guides or brush-limiting mechanisms that would prevent excessive wear of the brushes if the pipe were twisted off its ideal axial placement.
The device of U.S. Pat. No. 4,862,549 issued to Criswell et al. is an attachment for an existing drill consisting of an internal brush for cleaning of fittings and an external brush for cleaning of tubes prior to soldering that are provided in a single attachment that may be driven by either a manual or motor driven means. However, the device of Criswell et al. fails to provide any structure to maintain a pipe's end aligned while limiting deformation and wearing.
The device of U.S. Pat. No. 4,467,489 issued to Begneaud is a complex drill attachment that includes a brush device that is either manually operated or motor driven for cleaning the threads of bolts and studs and threaded pipe ends using combinations of bristles and solvent or air application.
The device of U.S. Pat. No. 4,014,062 issued to Scott et al. is a pipe-cleaning device that includes three rotating brushes and requires an Allen wrench to move each brush. As well, no inner cylindrical guide is present to align the pipe and prevent excessive wear of the brushes.
The device of U.S. Pat. No. 3,820,184 issued to Stone is a whole-pipe-cleaning device that includes multiple rotating brushes. There is no inner cylinder that would guide the pipe and maintain its alignment during use. This would lead to excessive brush wear and subsequent brush failure.
The device of U.S. Pat. No. 3,188,674 issued to Hobbs is a rotary tube end cleaner which is essentially a socket or cylindrical housing having a cylindrical inner surface lined with an abrasive material such as wire bristles, sandpaper and the like. The socket can be mounted to an electric drill and is provided with adjustment screws for changing the distance between the oppositely facing abrasive surfaces, thereby permitting adjustment for varying diameters of piping.
The device of U.S. Pat. No. 2,866,212 issued to White et al. is a pipe-cleaning device that includes a mechanism for cleaning both the inner and outer pipe surfaces. A significant problem with the design of this device is that any cleaning of the outer pipe surface may not be uniform. Indeed, the pipe is likely to be brushed in such a way that longitudinal ruts jeopardize the pipe thickness.
The device of U.S. Pat. No. 2,635,393 issued to Barth is a pipe-cleaning device that includes centrifugally-actuated bru
Morgan Eileen P.
Pandiscio & Pandiscio
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