Adjustment and control features for a power tool

Patent metadata

Field	Value
Publication number	US-9873158-B2
Application number	US-201414205664-A
Country	US
Kind code	B2
Filing date	Mar 12, 2014
Priority date	Mar 13, 2013
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

Improvements to a table saw include a system for automatically adjusting the height of the cutting blade in relation to the height of the workpiece, a system for providing fine adjustment of the height or bevel angle of the saw blade or work surface, and a system for automatic speed control and shut-off for the saw blade.

First claim

What is claimed is:

1. A height adjustment system in combination with a power tool having a table with a work surface for supporting a workpiece, a saw blade extending through a slot in the table surface, a carriage supporting the saw blade and a motor for driving the saw blade, and an adjustment mechanism for adjusting the height of the saw blade above the surface, the height adjustment system comprising:
an adjustment motor configured to drive the adjustment mechanism to increase or decrease the height of the saw blade relative to the work surface;
a movable sensor movably supported relative to the table and movable in response to movement of the adjustment mechanism, the movable sensor configured to direct a movable sensing beam at a non-perpendicular angle relative to the work surface, the beam passing through a position above the work surface directly above a predetermined location along the work surface, which position above the work surface is calibrated to the height of the saw blade, the movable sensor further configured to generate a movable sensor signal in response to detecting detection of the workpiece in the path of the movable sensing beam;
a controller configured for controlling the adjustment motor to change the height of the saw blade relative to the work surface in response to said movable sensor signal; and
a first sensor directly below said predetermined location and configured to direct a first sensing beam upward through the slot substantially perpendicular to the work surface to intersect said movable sensor beam and to generate a first sensor signal in response to the detection of the workpiece in the path of said first sensing beam,
wherein the controller is configured to control the adjustment motor in response to said movable sensor signal only upon receipt of said first sensor signal.

2. The height adjustment system in combination with the power tool of claim 1 , wherein:
the movable sensor is movable in response to movement of the adjustment mechanism to change said position above the work surface; and
the controller is configured to cause the adjustment motor to drive the adjustment mechanism until the upper edge of the workpiece at said predetermined location is detected in response to the movable sensor signal.

3. The height adjustment system in combination with the power tool of claim 2 , wherein the controller is configured to detect the upper edge of the workpiece in response to a change of state of the movable sensor signal between detecting and not detecting the workpiece in the path of said movable sensing beam.

4. The height adjustment system in combination with the power tool of claim 1 , further comprising:
a second sensor at a location between the saw blade and said predetermined location, said second sensor configured to direct a second sensing beam upward through the slot substantially perpendicular to the work surface and to generate a second sensor signal in response to the detection of the workpiece in the path of said second sensing beam; and
wherein said controller is configured to stop the adjustment motor upon receipt of said second sensor signal.

5. The height adjustment system in combination with the power tool of claim 1 , further comprising:
a user interface operable to generate a stop signal directing the user to stop moving the workpiece and a go signal directing the user to move the workpiece to the saw blade; and
said controller is configured to direct the user interface to generate the stop signal upon receipt of said first sensor signal and to direct the user interface to generate the go signal in response to detection of the upper edge of the workpiece.

6. The height adjustment system in combination with the power tool of claim 1 , wherein said movable sensor is movable in response to movement of the adjustment mechanism so that said position of said movable sensing beam is maintained equal to the blade height.

7. The height adjustment system in combination with the power tool of claim 1 , wherein said movable sensor is movable in response to movement of the adjustment mechanism so that said position of said movable sensing beam is maintained equal to a predetermined percentage of the blade height not equal to 100% of said blade height.

8. The height adjustment system in combination with the power tool of claim 1 , wherein said controller is further configured to determine a workpiece velocity in response to detection by said movable sensor of the upper edge and the lower edge of the workpiece as it moves toward the saw blade.

Assignees

• Bosch Tool Corp
• Bosch Gmbh Robert

Inventors

• Koegel Jan
• Luginbill Michael
• Assaliyski Marin

Classifications

• Y10T83/7726

  By movement of the tool · CPC title

• B27G19/02

  for circular saws · CPC title

• B23D45/068 Primary

  the saw blade being adjustable according to depth or angle of cut (B23D45/061, B23D45/065 take precedence) · CPC title

• B23D59/002

  for the position of the saw blade (mounting for swiveling or tilting a circular saw blade B27B5/36; portable power-driven circular saws with adjustment for cutting depth or amount of tilting B27B9/02) · CPC title