Cutting – With means to convey work relative to tool station – Cut made parallel to direction of and during work movement
Reexamination Certificate
2000-05-03
2004-01-06
Ashley, Boyer (Department: 3724)
Cutting
With means to convey work relative to tool station
Cut made parallel to direction of and during work movement
C083S435130, C083S522250, C083S437200, C083S438000, C083S581000, C033S469000, C033S471000
Reexamination Certificate
active
06672190
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to woodworking equipment, and in particular, to an apparatus for precisely orienting a workpiece in a predetermined angular relationship to a cutting tool.
BACKGROUND OF THE INVENTION
Operations associated with the cutting of wood or other materials with a power tool require the workpiece to be positioned accurately relative to the tool in order to achieve the desired results. In certain applications, the positioning of the workpiece is accomplished through the use of a “fence” which is positioned relative to the tool. Often, such as in table saw applications, the workpiece must be positioned such that the fence is at an angle relative to the saw blade. The typical method to achieve such angular positioning is to couple the fence to a miter gauge slidably disposed on the working surface of the table saw.
The use of a miter gauge in combination with a table saw is well-known in the art. Indeed, most table saws are sold with a miter gauge as a standard piece of equipment associated with the saw. In most cases, even when performing cuts in which the fence is perpendicular to the saw blade, the fence against which the workpiece is positioned is secured to a miter gauge set at a zero-degree angle.
Traditional miter gauges suffer from a wide variety of shortcomings. Notably, they typically lack the repeatability necessary to replicate cuts at specific angles without undue experimentation. This is caused, in large part, because existing miter gauges typically provide pre-defined stops at certain specific angles, typically 0, 15, 22½, 30, and 45 degrees. At any angle other than these limited positions, an accurate angular setting must be performed by trial-and-error.
But even when the woodworker intends to make a cut using one of the pre-defined stops on an existing miter gauge, the accuracy or repeatability of the cut is not absolute. On a typical existing miter gauge, a shot pin slidably connected to a fixed base is inserted into pre-drilled holes on the angularly adjustable miter head corresponding to the various pre-defined angular settings. The shot-pin mechanism requires that the hole have a diameter that is larger than the diameter of the shot pin. That difference in diameter introduces some angular error into the miter gauge. Further error arises from the mechanical sleeve in which the shot pin is secured to the fixed base of the miter gauge. Because the shot pin must be free to slide within that sleeve, lateral movement of the pin within the sleeve will lead to an angular position error when the pin is inserted into the holes in the miter head.
A further shortcoming of existing miter gauges is that they cannot provide the rigidity necessary for many woodworking operations. The lack of rigidity arises because, when an angle, other than one for which the shot-pin mechanism is provided, must be used, the pivoting miter head is secured to the fixed base through a bearing load applied through a single bolt. Typically, that bolt is inserted through a curved slot in the pivotable miter head and threaded into the fixed base. When the miter head is set at the desired angle, the bolt is tightened placing a bearing load between the miter head and a shoulder of the bolt and between the miter head and the base, thereby inhibiting angular movement of the miter head. Because the miter head is held in position only by the bearing load applied through the single bolt, the amount of torque applied to the miter head during certain woodworking operations, especially those involving large workpieces, may overcome the bearing load, causing an undesired rotation of the miter head.
One example of an existing table-saw miter gauge is described in U.S. Pat. No. 5,038,486 issued to Ducate, Sr. The '486 patent describes a typical miter gauge using a shot-pin mechanism for angularly positioning the miter gauge at certain pre-defined angles. For any angle other than the angles having a hole in the miter head for receiving the shot pin, the angular position is determined using a scale imprinted on the miter head. Assuming that such a scale was accurate, existing miter gauges such as in the '486 patent do not provide any method other than simple visual estimation for setting the miter-head angle at any angle that does not have a corresponding mark on the scale.
Therefore, what is needed is a miter gauge capable of performing precision miter cuts without requiring trial-and-error setups. The miter gauge should be capable of precisely orienting a workpiece with respect to the blade of a cutting tool with a resolution of finer than one-half degree. The ability to perform repeated cuts of precise angles should also be enabled by the miter gauge intended as a solution to prior art limitations.
SUMMARY OF THE INVENTION
The present invention seeks to resolve the above and other problems with the prior art. More particularly, the invention is an advancement in the art by providing a precision miter gauge achieving the objects listed below:
It is an object of the present invention to provide a precision miter gauge capable of making precision miter cuts when used with a cutting tool such as a table saw.
It is a further object of the present invention to provide a miter gauge capable of securely positioning a workpiece relative to a cutting tool.
It is a further object of the present invention to provide a miter gauge capable of delivering precision, repeatable miter cut accuracy without trial-and-error setups.
It is still a further object of the present invention to provide a miter gauge with positive angle stops capable of providing angular measurement accuracy and absolute miter gauge engagement to one-half degree of precision.
It is a further object of the present invention to provide a miter gauge allowing continuous angular adjustment capable of establishing miter cuts with finer than one-half degree of precision.
It is a further object of the present invention to provide a miter gauge capable of being employed with a slot disposed on either side of a cutting tool.
To accomplish the foregoing objects, the present invention provides a miter gauge for orienting a workpiece with respect to a cutting tool including a base, a pivotable body pivotably connected to said base, the pivotable body having a positioning edge, the positioning edge containing a plurality of teeth defining a plurality of notches between the teeth, a positioning member connected to said base, the positioning member including a teeth interface element configured to be inserted into at least one of the notches, and means for inhibiting movement of the pivotable body relative to the base.
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Taylor Design Group, Inc.,Owner's Manual for Incra Miter Sled, 1999.
The Osborne Manufacturing Company,Instruction Manual for The Osborne Miter Guide.
Ashley Boyer
Druan, Jr. Thomas J
Hilton Robert C.
Taylor Design Group, Inc.
Thompson & Knight LLP
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