Gas separation – Combined or convertible
Reexamination Certificate
2002-01-31
2003-11-04
Smith, Duane (Department: 1724)
Gas separation
Combined or convertible
C055S500000, C055S502000, C055SDIG003, C173S075000, C173S207000, C175S075000, C175S209000, C408S067000
Reexamination Certificate
active
06641634
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is based on a manual machine tool with a vacuum device for dust removal.
A hammer drill is made known in U.S. Pat. No. 4,192,390 that includes its own vacuum device for dust removal, with which the boring dust produced can be suctioned—according to the vacuum cleaner principle using suction air—into a dust collection box mounted on the hammer drill in relatively complicated fashion, with the suction air passing through a lamellar dust filter onto which the boring dust is deposited and collects in the dust collection box. The dust collection box is intended to remain attached to the hammer drill and has a base that can be swung open to empty the boring dust.
Another hammer drill is made known in U.S. Pat. No. 5,467,835 that comprises a vacuum device for dust removal with which boring dust that is produced can be suctioned—also according to the vacuum cleaner principle using suction air—into a separate dust collection box installed in a housing in removeable fashion. A fluted filter is situated in front of the suction port of the dust collection box facing the suction fan, onto which the dust is deposited when suction air passes through and collects in the dust collection box, so that pure air is transported toward the suction fan. The dust collection box can be detached from the housing to empty the boring dust, and the boring dust can be emptied through the entrance port.
The dust collection boxes of the two known hammer drills can be emptied only by way of a relatively complicated procedure, whereby replacement of the lamellar or fluted filter is a complicated procedure. Moreover, these dust collection boxes are unsuited for self-contained attachment to manual machine tools with integrated vacuum devices for blowing in the dust.
Manual machine tools are also known that are provided with plastic cassettes serving as dust collection boxes that are either provided with a multitude of air vents and are lined with filter material—similar to a grass catcher used with lawn mowers—or that consist of porous, only slightly dimensionally stable, air-permeable plastic that cleans the air blowing in the dust released from the container and is intended to retain the dust inside it. Both plastic cassettes tend to become plugged, and they are difficult to empty and clean.
In the known dust collection box, a specially-formed sealing lip made of the same material as the housing is produced during injection-molding. This can be achieved only if relatively soft material such as polypropylene (PP) is used as the housing material. When materials such as PA6 (polyamide, quality class
6
) or light-metal die casting, for example, are used to make the housing for dust collection boxes, separate rubber-elastic seals must be installed instead.
In the known dust collection box, a specially-formed sealing lip made of the same material as the housing is produced during injection-molding. This can be achieved only if relatively soft material such as PP is used as the housing material. When materials such as PA6 or light-metal die casting, for example, are used to make the housing for dust collection boxes, separate rubber-elastic seals must be installed instead.
SUMMARY OF THE INVENTION
The manual machine tool according to the invention with vacuum device for dust removal has the advantage, in contrast, that a particularly lightweight and compact dust collection box was created than can accommodate a large volume of blown-in dust without losing its inherent stability, whereby the removal by suction of the grinding dust from the tool takes place with a consistently high level of effectiveness and a long usable filter life with improved fine-dust filtration practically until the maximum fill level is reached.
Due to the fact that the dust collection box is held tightly against the manual machine tool—except at the dust blow-out connection of the manual machine tool—by way of a projection on its top cover, the forces of deformation produced when the dust collection box becomes full of dust are reduced to the extent that the cross-sections of the walls of the dust collection box can be minimal and, as a result, the dust collection box is particularly lightweight but stable, i.e., not
Due to the fact that the dust collection box, as a case open on the top, is provided with a removeable cover that closes the opening from above, only a minimal loss of pressure occurs during dust removal, whereby the dust can be disposed of particularly conveniently by opening the cover, without creating a dust cloud and polluting the environment.
Due to the fact that only the cover carries a filter, in particular a fluted filter, and it is the only part of the dust collection box provided with air vents, the filter surface can be designed to be particularly large in size. As a result, the air carrying the dust becomes blocked only to a minimal extent, and the vacuum device for dust removal is highly effective. Additionally, the dust can come loose from the fluted filter automatically when it reaches a certain layer thickness and fall into the dust collection box under the influence of gravity.
Due to the fact that the surface of the dust collection box with the cover is tilted in comparison with the direction of flow of the blow-out air in such a fashion that the dust collection box tapers toward the machine in the shape of a wedge, dust-preventing flow conditions are created for the blow-out air that optimize the removal of dust.
Due to the fact that the cover is held tightly against the dust collection box in elastic and impermeable fashion, it is particularly easy to open and close. The indentations on the sides of the dust collection box provided for opening purposes make it easier for the operator to establish a hold with his fingers and handle the dust collection box using one hand without the use of tools when removing, emptying, and reattaching the dust collection box.
Due to the fact that sealing lips are arranged in the blow-in connection of the dust collection box that encompass the dust blow-out connections of the manual machine tool and act as a seal, the dust collection box is reliably dust-proof during operation of the manual machine tool.
Due to the fact that the fluted filter is situated only in the cover of the dust collection box, it is particularly easy to replace in that a new one is either attached using adhesive, or the entire cover is replaced along with the filter.
Due to the fact that the dust collection box can be attached to the manual machine tool using locking levers designed in the shape of a rocker, it can be removed, emptied, and reattached in particularly convenient and time-saving fashion.
Due to the fact that the blow-in connection of the dust collection box can be closed using a valve, dust can be effectively prevented from escaping unintentionally when the dust collection box is removed from the manual machine tool.
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patent: 5467835 (1995-11-01), Mueller-Boysen
patent: 5738177 (1998-04-01), Schell et al.
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patent: 0 558 253 (1993-09-01), None
Hoffman Andreas
Mueller-Boysen Ulrich
Reich Doris
Scheschark Franz
Wuensch Steffen
Pham Minh-Chan T.
Robert & Bosch GmbH
Smith Duane
Striker Michael J.
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