Patent Application
20070232206
This invention relates to a machine and consumables for grinding surfaces, such as those formed of concrete, and particularly to an improved method for the collection of dust and other loose material generated as part of the grinding process.
A common problem that arises in grinding applications is dust or fines left on the surface that is being ground. Conventional systems, even those with relatively efficient dust extraction, leave a large quantity of dust and other material on the ground or other surface being treated. This becomes a problem in four ways.
First, as a grinding process is being carried out, the grinding surfaces pass over the loose material, effectively grinding it as much as the surface being treated. This shortens the life of the grinding surface itself, as well as increasing the overall time to complete a particular job.
Second, the working surfaces of grinders are often cooled with water, producing a dust-water mixture called slurry. Cleaning up the slurry adds time to a grinding operation.
Third, the dust left on the ground obscures the operator's view of the work surface. It is difficult to achieve a consistent finish if the operator cannot judge the amount of material being removed.
An additional problem with typical grinding machines is that the high surface feet-per-minute rate grinding of generates a great deal of heat through friction that can decrease the life of the tool.
The invention is directed to methods and arrangements for collecting dust in machines adapted to grind surfaces that address these problems.
In one aspect of the invention, plug for a grinding machine comprises a hole bored in the plug for use as a dust collection port.
In another aspect of the invention, plug for a grinding machine comprises a plurality of holes bored in the plug for use as dust collection ports.
In another aspect of the invention, a grinding machine comprises a housing; a drive mechanism, including a shaft extending through the housing; a shroud surrounding the shaft and abutting the housing to form a plenum; a head connected to the drive mechanism; at least one grinding plug having a working surface mounted in the head; and at least one channel extending from proximate the working surface into the plenum.
In another aspect of the invention, a plug-type grinding machine comprises one or more individual shrouds for each grinding plug.
The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:
This invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items.
Referring to
In this embodiment, the frame 100 is connected to a drive mechanism including wheels (not shown) and a handle assembly with controls (also not shown), as is conventional in the art. A dust collection system (not shown), including a dust collection bin or bag, may be mounted in or on the housing, or may be separate from the floor grinding machine 1.
In the exemplar embodiment, the frame 100 is connected to the housing 200 that supports a motor (not shown) for driving the grind assembly 400 via shaft 150. The housing 200, constructed of sheet steel or other durable material, includes a top portion 202 as well as peripheral wall portions 204 that extend to the floor or other surface to be ground. The wall portions may include seals 206 where they meet the surface to be ground. The seals, when used, may be rubber or plastic gaskets, nylon bristles, metal shrouds, or any other suitable material or structure, as would be understood by one of skill in the art.
The shaft 150 projects through the housing 200 and drives one or more heads 240 in a rotating fashion. In some embodiments, a coupling mechanism 270, such as a Morflex® coupler, may be positioned between the shaft 150 and the one or more heads 240. In one embodiment, the grinding machine 1 includes two heads 240.
In this exemplar embodiment, each head 240 includes at least one bore 245 for receiving a wear plug 300. In some embodiments, the bores 245 are tapered, so that the wear plugs 300 may be held in place by a friction fit, aided by the weight of the machine. In one embodiment, each head 240 includes three bores 245 for receiving three wear plugs 300.
The wear plugs 300 of this embodiment may be made of any appropriate materials or materials. One suitable plug is the Blastrac® X Type Diamond Plug. This plug has an X-shaped extension with a course grit diamond coating. A Blastrac® X Type Diamond Plug modified for use with one embodiment of the invention is illustrated on
It should be understood that other wear plugs may be suitable for use with the invention, as would other types of consumables, including discs or wheels, as would be understood by one of skill in the art.
In the exemplar embodiment, the wear plugs 300 are generally cylindrical and are tapered along at least part of their length, so as to facilitate the friction fit into bores 245. In other embodiments, the wear plugs 300 may be shapes other than cylinders and may or may not be tapered. Other methods of securing the wear plugs 300 into the bores 245 may also be used, including threads, clips, pins, bolts, or any other appropriate method.
In some embodiments, the wear plugs 300 are attached to the floor grinding machine 1 by other means, such as by surface mounting and fixation to the head 240 by means of the bolt or other threaded element, or otherwise. The method of connecting the wear plugs to the machine is not material to the invention.
The wear plugs 300 include a working surface 305, commonly coated with a thickness of diamond grit or another abrasive, and one or more channels 310. By “working surface” it is meant the portion of the plug that performs the grinding operation. In the case of the Blastrac® X Type Diamond Plug, for example, the working surface would include the face of the “X,” indicated by reference numeral 305 in
In one embodiment of the invention, the wear plugs 300 include one channel 310 in the center of the wear plug 300, along its axis. In other embodiments, there may be, in addition to or instead of a center channel, a plurality of channels 310 spaced around the axis of the wear plug 300, either regularly or irregularly.
In the illustrated embodiment, the channels 310 are cylindrical bores that are approximately ⅜ of an inch in diameter, although other cross-sectional shapes and sizes could be appropriate. Other embodiments may employ a larger number of channels of the same, a smaller, or a larger cross-sectional area. In some cases, channels 310 may be of one or more different diameters.
Where the channels 310 are spaced about the axis, they may run in a direction parallel to the axis of the plug, or some or all may taper in the direction of, or away from, the axis.
The channels 310 may be arranged such that they all exit the wear plugs 300 and the same radial distance from the axis, or, in other embodiments, the channels 310 may exit the wear plugs 300 at different radial positions relative to the axis of the wear plug 300. In some embodiments, the channels 310 may exit the plug through the working surface 300; in others, they may exit the plug a position proximate to, but not on, the working surface 300.
In the illustrative embodiment, the wear plug 300 also includes a recess 320 in the end opposite the working surface 305. The recess 320 may be sized and positioned such that each channel 310 opens into recess 320, forming a small plenum, rather than extending to the top of the plug.
In some embodiments, the inventive system includes individual plug shrouds 330 enclosing the portion of each wear plug 300 that protrudes below the head 240. The plug shrouds 330 may be made of a flexible material, such as urethane, and may be held in place by friction and/or by a taper on the wear plugs 300. In some embodiments, the plug shrouds 330 are sized to have the same axial length as the portion of the wear plug 300 extending below the head 240. As the wear plugs 300 are worn, the plug shrouds 330 also wear, so that shrouds 330 always extend to the working surface.
In some embodiments, the plug shrouds 330 may include one or more reliefs (not shown) formed on the inside (i.e., the side in contact with the wear plug 330) to facilitate the flow of air and/or reduce clogging.
On the upper surface of the head 240 of this embodiment there are projecting tubular cuffs 250 that are positioned to correspond to the location of each wear plug 300. In the illustrative embodiment, the cuffs 250 are terminated in a plane such that the radial outermost portion extends further above the top side of the head 240 than the radial innermost portion. The cuffs 250 each receive a hose 260 made of an abrasive resistant material. The hoses 260 may be sized for a friction fit over the cuffs 250 and/or may be secured with a clamp or by other means.
The other end of each hose 260 is connected to an inverted shroud 210. The inverted shroud 210 is bowl-shaped and surrounds the shaft 150. The bottom of the shroud 210 is connected to the shaft 150, directly or indirectly, such that it rotates with the shaft 150. The shroud 210 is flexible and is also constructed of an abrasive resistant material. The lip 215 of the shroud rests against, but is not connected to, the lower surface of the top 202 of the housing 200.
Extending through the top 202 of the housing 200 is at least one dust evacuation port 280. The port 280 is positioned such that it communicates with the plenum formed by the shroud 210 and the top of the housing 202. The port 280 may be perpendicular to the top of the housing or, as in the illustrative embodiment, arranged with its axis at an angle relative to the top 202 of the housing 200.
An evacuation hose (not shown) connects the port 280 to a dust collector (also not shown).
In operation, the dust collector draws air and entrained dust and fines through the channel(s) 310 in each plug, through the recess 320 in each plug, through the cuffs 250 on the head 240, through each hose 260, and into the plenum formed by the shroud 210 and the top 202 of the housing 200. The air, dust, and fines are then drawn through the port 280 and into the dust collector.
There are at least four benefits of the inventive system of this invention. First, dust is removed much more effectively than previous methods. Second, with more effective dust removal, the grinding tool itself is able to operate more efficiently. Third, the focused flow of air through the plugs cools the wear plugs 300, including any diamond or other material forming the working surface 305, and prolongs the life of the plug. Fourth, the material is removed more efficiently from the surface being treated, allowing the operator a better view of the progress being made.
The holes in the grinding tooling, in effect, become high velocity ports in close proximity to the development of dust. The ports travel with the plug, immediately capturing airborne dust as well as dust falling back to the surface. As a result, only a minimal amount of dust falls to the surface between plugs, allowing each successive plug can more efficiently engage the work surface. The system also allows air to flow through the tool, dissipating heat and avoiding clean-up associated with water-cooling of the wear plugs or working surface.
Another embodiment of the invention is illustrated in FIGS. 5A-D. In this arrangement, a head 500 carries three wear solid wear plugs 510, which may be mounted by any suitable method. Optional shrouds 520 are positioned about the solid wear plug 510. One or more local dust evacuation ports 530 extend through the circular head 500 and communicate with a gap between the solid wear plugs 510 and the shrouds 520. This embodiment provides localized high velocity ports that travel with each solid wear plug 510, without the need for channels extending though the plugs themselves.
FIGS. 6A-C depict another embodiment of the invention. In this arrangement, a head 600 carries three solid wear plugs 610, mounted, as above, in any appropriate manner. Positioned behind each wear plug 610, relative to the direction of travel of the rotating head 600, are elongated evacuation ports 630. The elongated evacuation ports 630 extend through the head 600 and to the surface being treated. The elongated evacuation ports 630, which may be made of any appropriate rigid or semi-rigid material and have a cross-section that is rectangular or any other suitable shape, wear as the plugs 610 wear and provide localized high-velocity dust collection.
FIGS. 7A-B show a head 700 that includes a plurality of wear plugs 710. Positioned behind each wear plug 710, relative to the direction of travel of the rotating head 700, are elongated agitators 720. The agitators, which may be made of bristles, urethane, neoprene, or any other appropriate rigid or semi-rigid material, operate to stir up dust or other debris from the surface of being treated to allow it to be entrained in the flow of air to a dust collection system. Elongated agitators 720 may be used in a system with conventional dust collection, or in conjunction with one or more of the localized, high velocity systems described above.
Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.
This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 60/785,787, entitled “Device And Method For Extraction Of Dust From A Grinder,” filed on Mar. 24, 2006, which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60785787 | Mar 2006 | US |
