Woodworking – Work guide – Work urged laterally
Reexamination Certificate
2000-01-13
2001-11-13
Bray, W Donald (Department: 3725)
Woodworking
Work guide
Work urged laterally
Reexamination Certificate
active
06315016
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to work tables for power tools and the like, and more particularly, is directed to a combination workpiece positioning/hold-down and anti-kickback device for a work table.
A work table for a woodworking device, such as a power saw, router and the like, generally includes a horizontal tabletop on which the workpiece is supported and a fence secured to the tabletop and extending in the direction of movement of the workpiece. The workpiece is moved on the upper surface of the tabletop and is guided along the fence, during a cutting or other woodworking action.
Featherboard and other devices are known for pressing the workpiece against the fence during such movement, and various hold-down devices are known for pressing the upper surface of the workpiece to hold the workpiece down on the tabletop. Some of these devices have some of the following desirable features.
One such feature is the ability to prevent kick-back of the workpiece during a woodworking operation. Another feature is the adjustment of the positioning or hold-down member in lengthwise, transverse and vertical directions relative to the workpiece. Still another feature is the ability to variably adjust the biasing force of the positioning or hold-down member against the workpiece. However, the applicant is not aware of any devices that include all of these features in a simple arrangement.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a combination workpiece positioning/hold-down and anti-kickback device that overcomes the aforementioned disadvantages.
It is another object of the present invention to provide a combination workpiece positioning/hold-down and anti-kickback device that presses the side and/or top surface of the workpiece, while preventing kick-back thereof.
It is still another object of the present invention to provide a combination workpiece positioning/hold-down and anti-kickback device in which the positioning or hold-down member is adjustable in lengthwise, transverse and vertical directions relative to the workpiece.
It is yet another object of the present invention to provide a combination workpiece positioning/hold-down and anti-kickback device in which the biasing force of the positioning or hold-down member against the workpiece is variably adjustable.
In accordance with an aspect of the present invention, a combination workpiece positioning and anti-kickback device for a work table having a fence against which a workpiece is guided, includes a positioning member having a main body, and an arcuate cam surface at one edge of the main body for engaging a side surface of a workpiece on the work table; an adjustment device for moving the positioning member relative to the workpiece, the adjustment device including a lengthwise adjustment assembly movable in a lengthwise direction of movement of the workpiece along the work table for adjusting the position of the positioning member in the lengthwise direction, and a transverse adjustment assembly movable in a direction transverse to the lengthwise direction for adjusting the position of the positioning member in the transverse direction, the transverse adjustment assembly being movably connected to the lengthwise adjustment assembly; a lengthwise releasable locking device for releasably locking the lengthwise adjustment assembly relative to the work table at a desired location in the lengthwise direction; a transverse releasable locking device for releasably locking the transverse adjustment assembly relative to the work table at a desired location in the transverse direction; a pivot which pivotally mounts the positioning member to the adjustment device for pivoting movement; a spring connected between the positioning member and the adjustment device for biasing the positioning member with a biasing force in a first pivot direction about the pivot such that the arcuate cam surface is biased in a direction opposite to a feed direction of the workpiece and into engagement with the side surface of the workpiece; and a variable tensioning device for variably adjusting the biasing force of the spring.
The main body is oriented substantially in the transverse direction, and the arcuate cam surface has a curvature with an increasing radius in a direction opposite to the direction of movement of the workpiece along the work table such that smaller radius portions of the arcuate cam surface extend closer toward the workpiece than larger radius portions of the arcuate cam surface. Preferably, the main body has an oblong shape.
The lengthwise adjustment assembly includes a first guide track extending in the lengthwise direction, and a guide rail movable in the guide track in the lengthwise direction, the pivot pivotally mounting the positioning member to the guide rail for pivoting movement. In addition, the lengthwise adjustment assembly includes a second guide track extending in the lengthwise direction, the second guide track being collinear with the first guide track with a gap between the first and second guide tracks in which the positioning member is located.
The lengthwise releasable locking device includes a releasable clamping device for releasably clamping the guide rail to the first and second guide tracks at a desired location therealong. In this regard, each of the first and second guide tracks and the guide rail include teeth such that the teeth of the guide rail engage the teeth of the first and second guide tracks to prevent relative movement therebetween when the releasable clamping device releasably clamps the guide rail to the first and second guide tracks at a desired location therealong. Further, each guide track includes at least one lengthwise groove therein, and the guide rail includes at least one lengthwise rod which slidably extends within each groove to prevent transverse movement of the guide rail relative to the guide tracks.
The transverse adjustment assembly includes a first abutment secured to the first guide track for engaging one transverse side of the work table; and a second abutment for engaging an opposite transverse side of the work table. The transverse releasable locking device includes a releasable clamp secured to the second guide track and the second abutment for moving the second abutment into releasable engagement with the opposite side of the work table; and a threaded rod which connects the second abutment to the releasable clamp with an adjustable distance therebetween.
There is further provided a stop on the lengthwise adjustment assembly for limiting pivotal movement of the positioning member.
The variable tensioning device includes a threaded tensioning rod connected between the spring and the lengthwise adjusting assembly, and threadedly connected with the lengthwise adjustment assembly for variably changing the biasing force of the spring.
In accordance with another aspect of the present invention, a combination workpiece hold-down and anti-kickback device for a work table having a fence against which a workpiece is guided, includes a hold-down member having a main body, and an arcuate cam surface at one edge of the main body for engaging an upper surface of a workpiece on the work table; an adjustment device for moving the hold-down member relative to the workpiece, the adjustment device including a lengthwise adjustment assembly movable in a lengthwise direction of movement of the workpiece along the work table for adjusting the position of the hold-down member in the lengthwise direction, and a vertical adjustment assembly movable in a vertical direction transverse to the lengthwise direction for adjusting the position of the hold-down member in the vertical direction, the vertical adjustment assembly being movably connected to the lengthwise adjustment assembly; a lengthwise releasable locking device for releasably locking the lengthwise adjustment assembly relative to the work table at a desired location in the lengthwise direction; a vertical releasable locking device for releasably lock
Bray W Donald
Frishauf, Holtz Goodman, Langer & Chick, P.C.
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