Cutlery – Cutting tools – Plural cooperating blades
Reexamination Certificate
1999-01-08
2001-10-09
Rachuba, M. (Department: 3724)
Cutlery
Cutting tools
Plural cooperating blades
C030S279200, C030S280000, C030S289000, C030S292000, C083S873000, C083S875000, C083S495000
Reexamination Certificate
active
06298561
ABSTRACT:
FIELD OF THE INVENTION
The present invention refers to a tool for working board-like workpieces, in particular for working sandwich type plaster boards.
BACKGROUND ART
Sandwich type plaster boards such as gypsum plaster boards are to an increasing degree used in the building of houses. These boards are usually attached by means of screws onto a portative sub-structure. Large-surface walls can be established by assembling a plurality of boards. The joints formed between the individual boards can be filled by means of a filler material. Preferably a tape-like fleece material is put onto the filled joints which is finally smoothened.
Since in gypsum plaster boards the outer layers thereof significantly contribute to the strength of these boards, it proved to be advantageous in view of a high-quality processing of these boards to cut these boards comparatively precisely when needed so that the outer cover layers extend in an undamaged condition to the precisely defined edge of the board.
Cutting said boards to size is usually made by using a saw or a knife. Using a saw, the board can be easily separated completely. The edges are, however, relatively rough and are possibly jagged. When using a knife a smooth cutting edge can be achieved at least on one side of the board. In order to obtain a straight cut the use of a guide rail is imperative. When making short cuts, this guide rail can usually be held by hand. When making longer cuts, it is convenient to fix the guide rail for instance by means of screw clamps. If, however the guide rail is not fully straight or the board bends under the guide rail when being cut, there is a risk that the board is cut inaccurately and the blade of the knife does not penetrate sufficiently deep into the board so that a clearly defined separation line is not attained.
SUMMARY OF THE INVENTION
Facing this problem, the object of the invention is to provide a tool for cutting-to-size board-like workpieces, in particular gypsum plaster boards by means of which comparatively precise cuts can be made in a time-saving manner.
By the tool of the invention a clear cut is achievable having a precise edge of cut or notch in a board without the workpiece having to be marked or a guide rail having to be used.
An embodiment of the invention which is especially advantageous in view of an especially safe guide of the tool is provided in that the guide means has a lateral guide face which can be abutted with a side face of a workpiece. It is possible to provide this guide face with profiles and/or with a slideway lining.
To support the tool on the workpiece, the guide means is preferably designed in a manner that it comprises a rest-guide face which can be engaged with the flat side of a workpiece. Both guide faces are preferably arranged in a manner that the lateral guide face and the rest-guide face are substantially orthogonal to one another. In a corner portion formed between the two guide faces, a longitudinal recess of low depth is preferably provided into which possible projections in the end portion of the workpiece can penetrate without deflecting the guide means. If the existing workpiece edges do not allow a sufficiently precise guide of the tool, an especially precise guide of the tool can be achieved in that the guide means can be brought into guiding engagement with a guide ruler. Such a guide ruler preferably consists of an extruded profile, made for instance of aluminum.
An especially advantageous embodiment of the invention is given in that the coupling means comprises a rail element preferably formed of a flat steel profile. This rail element can preferably be fixed in the area of the guide means. The length of this rail element is in the range between 12 to 48 inches. The rail element substantially extends perpendicular to a tool moving direction.
The rail element is preferably arranged such that the flat side thereof is substantially aligned in parallel to the workpiece surface. This leads to an especially high flexural strength against possible forces directed in the tool moving direction.
An infinitely variable adjustability regarding the cutting depth is given according to a preferred embodiment in that a clamping means is provided for clamping the rail element in the area of the guide means. A sufficiently large clamping force can be achieved in that the clamping means comprises a clamping screw. This clamping screw is in an advantageous manner provided with a turning knob and can be turned manually, without the use of a tool, into a clamping or release position.
The blade means is, according to a special aspect of the present invention, preferably formed by a rolling blade element. The rolling blade element preferably has a diameter of preferably 0.3 to 2.4 inches. According to a preferred embodiment, the rolling blade element is supported in such a manner that a predetermined braking torque acts at the rolling blade element. The braking torque can adjusted according to the respective need. The rolling blade element is in an advantageous manner set onto a threaded stem, wherein a force acting on two brake discs can be adjusted via a polystop nut.
An especially favorable positioning of the rolling blade element can be achieved in that the blade means is attached at a carrier element. This carrier element allows a displacement of the blade element without the polystop nut preferably provided on the threaded stem for supporting the blade element having to be loosened.
The carrier element is attached at the rail element preferably through an angular holding member. The second handle means is fixed at and end portion of the rail element preferably through this holding member. It is also possible to adjustably attach the second handle means at the rail element.
The second handle means is attached according to a special aspect of the present invention in a manner that this handle means is arranged above the blade means when setting the tool onto a horizontally aligned board. A line extending orthogonally to the plane of the board and to a contact portion of the blade element extends preferably through the second handle means.
An embodiment that is especially advantageous from the ergonomic point of view is given in that the second handle means has a substantially spherical knob. In particular in combination with a second handle means that is designed in that manner, it is advantageous in view to a reliable guide of the tool to provide the first handle means with an elongate handle section. The handle section extends in an advantageous manner in the tool moving direction.
In view of an especially favorable handling of the tool, it is advantageous that a passage section is formed between the handle section and the guide means, and that the handle section has an end portion that is connected to the guide means. An especially stable embodiment is given in that the handle section and the guide means are formed integrally.
An especially robust fixing of the rail element can be achieved in that a fixing pin section is provided which is formed integrally with the guide means and that the clamping means comprises a clamping bracket element which can be set onto the fixing pin section for clamping the rail element at the guide means.
A simple and precisely positioned adjustability of the cutting width is given in that the rail element is provided with a scale for indicating the adjusted cutting width.
When working sandwich type plaster boards, in particular gypsum plaster boards, it is sometimes required to cut small strips off these boards in order to cut the boards to a predetermined size or to create strips of a predetermined width for further processing.
When processing gypsum plaster boards or cellulose boards, strips of that kind can be produced by slightly slitting the surface of the boards on both sides. After forming a separation line by preparatorily slightly slitting the boards on the both sides, e.g. by means of a rolling cutter blade, these boards are laid onto a rest face and are drawn forwards over a front edge of the rest face to an extent th
Laubscher Lawrence E.
Rachuba M.
LandOfFree
Tool for cutting sandwich type plaster boards does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tool for cutting sandwich type plaster boards, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tool for cutting sandwich type plaster boards will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2562943