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US 7,421,932 B1Granted
Power cutting tool comprising a radar sensing system
AssigneePower Tool Institute
InventorsFred J. Heinzmann, David C. Shafer
Life of this patent
Estimating the term…
Abstract
A power cutting tool having a movable blade, such as a table saw, comprising a radar sensing system for movement of an object in a region near the blade is disclosed. The radar sensing system emits a radio frequency wave and receives wave energy reflected by the object. The system measures the Doppler shift of the received wave energy to detect the presence of a fast moving object in a zone near the blade. When such a condition is detected, a reaction system can be activated to mitigate the condition.
Claims15
A power cutting tool comprising:
- a platform having a cutting surface;
- a movable blade for cutting an object on the cutting surface;
- and
- at least one radar sensing system comprising:
- an open-ended waveguide having a longitudinal axis parallel to the plane of the blade and perpendicular to the cutting surface, the open-ended waveguide having an open end at the cutting surface of the platform and adjacent to the blade;
- an antenna element positioned below the cutting surface, wherein the antenna element is inserted into the open-ended waveguide, and wherein the antenna element is perpendicular to the longitudinal axis of the open-ended waveguide;
- and
- circuitry connected to the antenna element for producing an output related to the velocity of an object in a velocity range in a region near the blade and above the cutting surface.
5 more elements
A table saw comprising:
- a table having a cutting surface;
- a rotatable blade disposed in an opening defined by the table such that at least a portion of the rotatable blade extends above the cutting surface;
- and
- at least one radar sensing system comprising:
- an open-ended waveguide having a longitudinal axis parallel to the plane of the blade and perpendicular to the cutting surface, the open-ended waveguide having an open end at the cutting surface of the platform and adjacent to the blade;
- an antenna element positioned below the cutting surface, wherein the antenna element is inserted into the open-ended waveguide, and wherein the antenna element is perpendicular to the longitudinal axis of the open-ended waveguide;
- and
- circuitry connected to the antenna element for producing an output related to the velocity of an object in a velocity range in a region near the blade and above the cutting surface.
5 more elements
A table saw comprising:
- a table having a cutting surface;
- a rotatable blade disposed in an opening defined by the table such that at least a portion of the rotatable blade extends above the cutting surface, the blade having first and second lateral sides;
- and
- a radar sensing system comprising:
- a first open-ended waveguide having a longitudinal axis parallel to the plane of the blade and perpendicular to the cutting surface, the first open-ended waveguide having an open end at the cutting surface of the platform and adjacent to the first lateral side of the blade;
- a first antenna element positioned below the cutting surface, wherein the first antenna element is inserted into the first open-ended waveguide, and wherein the first antenna element is perpendicular to the longitudinal axis of the first open-ended waveguide;
- a second open-ended waveguide having a longitudinal axis parallel to the plane of the blade and perpendicular to the cutting surface, the second open-ended waveguide having an open end at the cutting surface of the platform and adjacent to the second lateral side of the blade;
- a second antenna element positioned below the cutting surface, wherein the second antenna element is inserted into the second open-ended waveguide, and wherein the second antenna element is perpendicular to the longitudinal axis of the second open-ended waveguide;
- circuitry connected to the first and second antenna elements for producing an output related to the velocity of an object in a velocity range in a region near the blade and above the cutting surface.
6 more elements
Dependencies are inferred from the claim text.