Gear cutting – milling – or planing – Milling – With means to remove chip
Reissue Patent
1998-12-16
2001-06-26
Howell, Daniel W. (Department: 3722)
Gear cutting, milling, or planing
Milling
With means to remove chip
C144S252100, C409S182000
Reissue Patent
active
RE037247
ABSTRACT:
The invention relates to a router with a cutter head containing the drive motor which is held in a displaceable manner generally at two guide columns which are secured at a base plate frequently composed of several parts and which extend away from it vertically to its workpiece engagement surface, and with a tool holder for a cutter or the like provided at the side of the cutter head facing towards the base plate and coupled to the drive motor, in the axial extension of which the base plate is provided with an opening or recess for the passage of the cutter or the like wherein the base plate contains a suction intake channel which surrounds the opening or recess over at least the larger part of its periphery which channel has at least a suction intake opening facing towards the opening or recess and to which channel a suction extraction channel is connected which extends upwards from the base plate in the area of a guide column and runs in this area coaxially with this guide column and the end of which which is remote from the base plate can be connected to a suction extraction device.
In a known router of this type (EP 0 191 509 B1) a ring-shaped suction extraction channel extends from the suction intake channel upwards so that the one guide column forms the inner boundary wall and a bellows, the lower end of which is connected to the base plate and the upper end of which is connected to the cutter head, forms the outer boundary wall of the annular space. At the upper end of the annular space the suction extraction channel continues in a chamber surrounding the armature shaft in the cutter head and then runs downwards about the armature shaft into a fan chamber to which an attached suction extraction tube is connected which can be connected to a suction extraction device as for example a vacuum cleaner.
On this known structure the suction extraction channel is thus defined in its lower area by a bellows. The use of a bellows of this type for the relatively rough application in connection with a router is always associated with the risk that the bellows will be damaged so that then chips and dust particles extracted from the area of the cutter can emerge outwards through the damaged bellows. In addition the further course of the suction extraction channel inside the cutter head requires a relatively complicated and costly structure of the cutter head housing.
The object of the invention is to provide for a router with which dust removal can be carried out in a simple and reliable manner in the area of the cutter or the like.
To achieve this objective a router of the type mentioned in the introduction is constructed according to the invention in such a way that the one guide column is hollow and that the suction extraction channel runs inside the hollow guide column. In a particularly preferred embodiment the connection for the suction extraction device is provided at the upper end of the hollow guide column.
In the router according to the invention one of the guide columns is used for forming the suction extraction channel and constructed hollow for the purpose that on the one hand no additional components are required which form a wall of the suction extraction channel and which could be damaged in operation and thus become permeable and on the other hand a simple and substantially straight movement of the dust is achieved so that no excessively high vacuum is required for the suction removal and no dust particles can be deposited in the guide areas of the suction extraction channel.
The structure is particularly simple if the connection for the suction extraction device is provided at the upper end of the hollow guide column as then the complete suction extraction channel runs from the base plate to the connection for the suction device inside the hollow guide column, i.e. no connections or transitions are present which would require additional sealing.
The outside diameter of the hollow guide column is preferably larger than the outside diameter of the other guide column so that a suction extraction channel with a cross section which is adequate for effective dust collection can be formed in the hollow guide column.
In known routers the cutter head is usually supported via at least one pressure spring in relation to the base plate, so that the pressure spring can be located inside a guide column and is supported with one end at the base plate and with the other end at a section of the cutter head (EP 0 191 509 B1) extending telescopically from above into the guide column. If, however, as in the case of the router according to the invention, a hollow guide column is used so as to form the suction extraction channel with its inner space, no pressure spring can be disposed in this position.
In a router according to the invention it is preferred to provide a tension spring which surrounds the upper end of the hollow guide column on the outside between the cutter head and the upper end of the hollow guide column and this spring can for example be surrounded by a bellows. A tension spring of this type produces the spring tension required for moving the cutter head into its raised position and is not located in the area between cutter head and base plate, i.e. not in the area which in operation is particularly exposed to the danger of damage.
REFERENCES:
patent: 1581719 (1926-04-01), Carter
patent: 4051880 (1977-10-01), Hestily
patent: 4606685 (1986-08-01), Maier et al.
patent: 4938264 (1990-07-01), Ferenczffy
patent: 5584620 (1996-12-01), Blicklan et al.
patent: 191509 (1986-08-01), None
patent: 426321 (1991-05-01), None
patent: 2329392 (1977-05-01), None
Blickhan Stefan
Buchholz Achim
Ruckert Karl-Heinz
Sieber Gustave
Black & Decker Inc.
Harness & Dickey & Pierce P.L.C.
Howell Daniel W.
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