Woodworking – Process – Mechanical cutting or shaping
Reexamination Certificate
1999-07-21
2001-10-02
Bray, W. Donald (Department: 3725)
Woodworking
Process
Mechanical cutting or shaping
C144S117100, C144S115000, C144S242100, C144S246100, C144S248400, C144S250260, C144S116000, C144S375000, C198S782000, C198S836200, C451S190000, C451S301000
Reexamination Certificate
active
06296029
ABSTRACT:
The present invention relates to a method and apparatus for positioning workpieces in surfacing machinery, and in particular, a centering assembly for centering workpieces in a planer machine, specifically a centering sectional shoe assembly that adjusts for individual workpiece thicknesses and widths allowing multiple workpieces to be centered and planed at the same time by a planer machine having opposed cutting heads.
BACKGROUND OF THE INVENTION
Surfacing machinery is used to perform surface operations on workpieces, for example, to sand or plane lumber, planks, panels, etc. Such surfacing machinery typically includes upper and lower heads for cutting or sanding the workpieces, and a feed assembly for advancing the workpiece through the heads. The feed assembly preferably provides a self-centering effect so that whatever amount of material is being removed, one-half will be removed from each side, thereby maximizing yield.
Self-centering feed assemblies for abrasive grinding machines are disclosed in U.S. Pat. No. 4,322,919 issued to Gerber on Apr. 6, 1982 and in U.S. Pat. No. 4,640,056 issued to Stump on Feb. 3, 1987, both of which are herein incorporated by reference. These prior art feed assemblies allowed each workpiece to float or center at the sanding head position and to thereby achieve equal stock removal on each side of each board. Because the abrasive belt heads themselves had a self-centering effect, these feed assemblies were required to provide the necessary horizontal forces required to feed each board, but follow the surface of each board so as to not interfere with the centering effect at the abrasive belt heads.
However, when used in connection with cutting heads, as opposed to sanding or grinding heads, these prior art feed assemblies were not adequate to achieve the desired individual centering result, since the cutting heads do not provide a self-centering effect. This is due to the fact that when using cutting heads instead of abrasive heads, the vertical forces on the workpiece are exactly the opposite, as a cutting head tries to pull the board into the cutter, whereas an abrasive head tries to push the board away from the abrasive belt. As a result, the cutting heads would remove an unequal amount from each side and tend to gouge or otherwise cut the workpiece unevenly, especially if the workpiece is uneven, warped or contains other variations. In an attempt to compensate for such problems, the cutting heads normally are displaced relative to each other, as opposed to the desired position of directly opposing each other, resulting in uneven stock removal from each side.
Accordingly, there is a need in a cutting head planer machine for a method and apparatus to adequately center and feed workpieces to the cutting head assembly so that an equal amount of material will be removed from both sides of each and every board independent of individual board thickness variations. The present invention fulfills such a need.
BRIEF SUMMARY OF THE INVENTION
The present invention comprises a centering sectional shoe assembly for use in surfacing machinery, and in particular a planer machine having cutting heads. The shoe assembly is positioned in close proximity to the cutting heads (which directly oppose each other), and between the cutting heads and a centering feed assembly. The shoe assembly includes a plurality of individually movable pressure shoe sets, each set comprising an upper shoe and a lower shoe. Each shoe set is operatively connected to a closed circuit, double rod end hydraulic cylinder assembly which selectively and independently positions the shoe set responsive to the surface to the workpiece. A means for exerting a force is also operatively connected to each shoe set to provide a centering force. In use, as the upper or lower shoe of a shoe set is forced away from the centerline of the workpiece, the opposing shoe would automatically move the same amount. The shoe assembly thus centers each and every workpiece independent of the amount of stock removal required. Further, it is desirable that the feed assembly of the present invention likewise includes a closed circuit, double rod end hydraulic cylinder assembly to improve centering of the workpiece by the feed assembly.
Accordingly, it is the principle object of the present invention to provide a method and apparatus for positioning workpieces in surfacing machinery.
It is a further object of the invention to provide a centering assembly for centering workpieces in a planer machine.
It is also an object of the invention to provide a centering sectional shoe assembly that adjusts for individual workpiece thicknesses and widths allowing multiple workpieces to be centered and planed at the same time by a planer machine having opposed cutting heads.
It is an additional object of the present invention to provide a closed circuit, double rod end hydraulic cylinder assembly for a centering sectional shoe assembly.
It is another object of the present invention to provide an improved centering feed assembly having a closed circuit, double rod end hydraulic cylinder assembly.
Numerous other advantages and features of the invention will become readily apparent from the detailed description of the preferred embodiment of the invention, from the claims, and from the accompanying drawings in which like numerals are employed to designate like parts throughout the same.
REFERENCES:
patent: 4322919 (1982-04-01), Gerber
patent: 4457350 (1984-07-01), Finnila
patent: 4640056 (1987-02-01), Stump
patent: 4724877 (1988-02-01), Culley, Jr.
patent: 5368077 (1994-11-01), Croghan et al.
Oliver Machine Co., Engineering Drawings, 2040E10012, 2040E10012, 2040E10028, Apr./May 1986.
Bray W. Donald
Patula & Associates P.C.
Timesavers, Inc.
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