Miter saw with active control energy dampener

Patent metadata

Field	Value
Publication number	US-9387598-B2
Application number	US-201414209319-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 14, 2013
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

An automatic braking system for a pivoting power tool includes a cutting assembly, a cutting arm supporting the cutting assembly, a hinge supporting the cutting arm through a pivot, a primary braking system operably connected to the cutting assembly, a safety circuit configured to sense an unsafe condition and, in response to sensing the unsafe condition, control the primary braking system to oppose rotation of a blade supported by the cutting assembly, and a damper system operably connected to the cutting arm, the damper system configured to oppose rotation of the cutting arm when the primary braking system is controlled to oppose rotation of the blade.

First claim

The invention claimed is:

1. A method of operating an automatic braking system for a pivoting power tool, comprising:
supporting a cutting assembly with a cutting arm;
sensing an unsafe condition using a safety circuit;
controlling with the safety circuit a primary braking system to oppose rotation of a blade supported by the cutting assembly in response to sensing the unsafe condition;
opposing with a damper system rotation of the cutting arm about a pivot when the primary braking system is controlled to oppose rotation of the blade; and
controlling the damper system comprising controlling a linear damper operably connected to the cutting arm and to a bevel post supporting the cutting arm;
wherein the cutting arm includes a slot and the linear damper is pivotably attached to the bevel post at a first end portion and includes a second end portion positioned within the slot, and wherein controlling the linear damper comprises locking the second end portion within the slot.

2. The method of claim 1 , wherein opposing with a damper system comprises:
activating the damper system by angular acceleration of the cutting arm.

3. The method of claim 1 , wherein opposing with a damper system comprises:
controlling the damper system with the safety circuit in response to sensing the unsafe condition.

4. The method of claim of claim 3 , further comprising:
disengaging with the safety circuit a primary clutch through which the primary braking assembly is operably connected to a motor in response to sensing the unsafe condition.

5. The method of claim 4 further comprising:
rotating the blade with the motor through a pulley operably connected to the primary clutch prior to sensing the unsafe condition.

6. The method of claim 3 , wherein controlling with the safety circuit the primary braking system to oppose rotation of the blade occurs substantially simultaneously with controlling with the safety circuit the damper system.

7. An automatic braking system for a pivoting power tool, comprising:
a cutting assembly;
a cutting arm supporting the cutting assembly;
a hinge supporting the cutting arm through a pivot;
a primary braking system operably connected to the cutting assembly;
a safety circuit configured to sense an unsafe condition and, in response to sensing the unsafe condition, control the primary braking system to oppose rotation of a blade supported by the cutting assembly; and
a damper system operably connected to the cutting arm, the damper system configured to oppose rotation of the cutting arm when the primary braking system is controlled to oppose rotation of the blade;
wherein the damper system comprises a linear damper operably connected to the cutting arm and to a bevel post supporting the cutting arm;
wherein the cutting arm includes a slot and the linear damper is pivotably attached to the bevel post at a first end portion and includes a second end portion positioned within the slot; and
wherein activation of the damper system comprises locking the second end portion within the slot.

8. The automatic braking system of claim 7 , wherein the damper system is activated by angular acceleration of the cutting arm.

9. The automatic braking system of claim 7 , wherein the safety circuit is further configured to activate the damper system in response to sensing the unsafe condition.

10. The automatic braking system of claim 9 , wherein:
the primary braking assembly is operably connected to a motor through a primary clutch; and
the safety circuit is configured to disengage the primary clutch in response to sensing the unsafe condition.

11. The automatic braking system of claim 10 , wherein:
the primary braking assembly is operably positioned between the primary clutch and a pulley, the pulley operably connected to the blade.

Assignees

• Bosch Tool Corp
• Bosch Gmbh Robert

Inventors

• Voong Gary L
• Jayaraman Prashant

Classifications

• B23D47/00

  Sawing machines or sawing devices working with circular saw blades, characterised only by constructional features of particular parts (constructional features of these parts per se B23Q; details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00) · CPC title

• F16P3/008

  Devices for directly stopping or interrupting the drive or gear in case of danger to the machine, e.g. devices with clutches · CPC title

• Y10T83/081

  With randomly actuated stopping means · CPC title

• B26D1/16

  mounted on a movable arm or the like · CPC title

• B27B5/38

  Devices for braking the circular saw blade or the saw spindle; Devices for damping vibrations of the circular saw blade, e.g. silencing {(vibration-damping of sawing machines or devices working with circular saw blades B23D47/005)} · CPC title