Actuators for power tool safety systems

Patent metadata

Field	Value
Publication number	US-11865631-B2
Application number	US-202117228008-A
Country	US
Kind code	B2
Filing date	Apr 12, 2021
Priority date	Oct 2, 2009
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

Fast-acting and low-inertia actuators useable in various applications where a high force must be applied very quickly are disclosed. Power tools with detection systems configured to detect a dangerous condition between a person and a cutting tool are disclosed. In power tools, for example in a woodworking machine, a fast-acting and low-inertial actuator as disclosed herein can be used to retract a blade upon detection of a dangerous condition by a detection system. The actuator includes a charge of pressurized fluid and one or more electromagnets to selectively retain or release the pressurized fluid.

First claim

The invention claimed is:

1. A power tool comprising:
a blade for cutting workpieces;
a motor configured to drive the blade;
a structure supporting the blade and configured to allow the blade to retract; and
at least one electromagnet to trigger a retraction of the blade, and
a circuit that controls the at least one electromagnet, where the circuit is configured to supply current to the at least one electromagnet in a first direction to create a magnetic field and in a second direction to reverse the magnetic field.

2. The power tool of claim 1 , where the circuit that controls the at least one electromagnet with a microprocessor.

3. A power tool comprising:
a blade for cutting workpieces;
a motor configured to drive the blade;
a structure supporting the blade and configured to allow the blade to retract;
at least one electromagnet to trigger a retraction of the blade; and
a circuit that controls the at least one electromagnet with a microprocessor, where the circuit is configured to supply current to the at least one electromagnet in a first direction to create a magnetic field and in a second direction to help dissipate the magnetic field.

4. The power tool of claim 1 , 2 , or 3 , further comprising a detection system configured to detect a dangerous condition between a person and the cutting tool, and where the at least one electromagnet triggers the retraction of the blade upon detection of the dangerous condition.

5. A power tool comprising:
a blade for cutting workpieces;
a motor configured to drive the blade;
a structure supporting the blade and configured to allow the blade to retract;
at least one electromagnet to control retraction of the blade, and
a circuit that controls the at least one electromagnet, where the circuit is configured to supply current to the at least one electromagnet in a first direction to create a magnetic field and in a second direction opposite the first direction.

6. The power tool of claim 5 , where the circuit controls the at least one electromagnet with a microprocessor.

7. A power tool comprising:
a blade for cutting workpieces;
a motor configured to drive the blade;
a structure supporting the blade and configured to allow the blade to retract;
at least one electromagnet to control retraction of the blade; and
a circuit that manages the at least one electromagnet with a microprocessor, where the circuit is configured to supply current to the at least one electromagnet in a first direction to create a magnetic field and in a second direction to help dissipate the magnetic field.

8. The power tool of claim 5 , 6 , or 7 , further comprising a detection system configured to detect a dangerous condition between a person and the cutting tool, and where the at least one electromagnet causes the blade to retract upon detection of the dangerous condition.

Assignees

• Sawstop Holding Llc

Inventors

• Gass Stephen F

Classifications

• B27G19/022 Primary

  with blades dropping below a table in reaction to dangerous situation · CPC title

• B23D47/10 Primary

  actuated by fluid or gas pressure · CPC title

• B23D59/001

  Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade (measuring in general G01; controlling in general G05) · CPC title

• B27G19/02

  for circular saws · CPC title

• F15B15/19

  Pyrotechnical actuators · CPC title