Diagnostic and Maintenance Operation for a Saw

Patent metadata

Field	Value
Publication number	US-2016263674-A1
Application number	US-201615060664-A
Country	US
Kind code	A1
Filing date	Mar 4, 2016
Priority date	Mar 12, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

A method for measuring brush wear in a motor of a saw includes generating, with a sensor connected to a brush in a motor of the saw, a first signal corresponding to a level of wear in the brush and identifying, with a controller, a level of wear for the brush with reference to the first signal. The method further includes generating, with the controller and a user interface device, an output requesting replacement of the brush in response to the identified level of wear exceeding a predetermined threshold.

First claim

What is claimed:

1 . A method for monitoring brush wear in a motor of a saw comprising:
generating, with a sensor connected to a brush in a motor of the saw, a first signal corresponding to a level of wear in the brush; identifying, with a controller, a level of wear for the brush with reference to the first signal; and generating, with the controller and a user interface device, an output requesting replacement of the brush in response to the identified level of wear exceeding a predetermined threshold.

2 . The method of claim 1 further comprising:
generating, with a current source in the motor, an electrical signal that passes through the brush;
identifying, with the controller, a level of electrical resistance through the brush with reference to the first signal from the sensor; and
identifying, with the controller, that the level of wear in the brush exceeds the predetermined threshold in response to the level of electrical resistance being below a predetermined threshold.

3 . The method of claim 2 , the generating of the first signal further comprising:
generating with the sensor the first signal corresponding to at least one of a level of electrical current or voltage in the brush.

4 . The method of claim 1 further comprising:
generating, with the sensor, the first signal corresponding to a level of pressure exerted upon the sensor from a spring that biases the brush into contact with a commutator in the motor; and
identifying, with the controller, that the level of wear in the brush exceeds the predetermined threshold in response to the level of pressure being below a predetermined threshold.

5 . The method of claim 1 further comprising:
disabling, with the controller, operation of the motor in response to the identified level of wear exceeding the predetermined threshold.

6 . The method of claim 1 wherein the sensor generates the first signal during a diagnostic mode in which the motor is deactivated.

7 . A system for measuring brush wear of a motor in a saw comprising:
a motor in a saw; a brush in the motor; a sensor in the motor, the sensor being configured to generate a first signal corresponding to a level of wear in the brush; a user interface device; and a controller operatively connected to the motor, the sensor, and the user interface device, the controller being configured to:
receive the first signal from the sensor;
identify a level of wear for the brush with reference to the first signal; and
operate the user interface device to generate an output requesting replacement of the brush in response to the identified level of wear exceeding a predetermined threshold.

8 . The system of claim 7 further comprising:
a current source in the motor configured to generate an electrical signal that passes through the brush;
the sensor being further configured to:
generate the first signal corresponding to at least one of a level of electrical current or voltage in the brush; and

the controller being further configured to:
identify a level of electrical resistance through the brush with reference to the first signal from the sensor; and
identify that the level of wear in the brush exceeds the predetermined threshold in response to the level of electrical resistance being below a predetermined threshold.

9 . The system of claim 7 , the sensor being further configured to:
generate the first signal corresponding to a level of pressure exerted upon the sensor from a spring that biases the brush into contact with a commutator in the motor; and the controller being further configured to:
identify that the level of wear in the brush exceeds the predetermined threshold in response to the level of pressure being below a predetermined threshold.

10 . The system of claim 7 , the controller being further configured to:
disable operation of the motor in response to the identified level of wear exceeding the predetermined threshold.

11 . The system of claim 7 wherein the sensor generates the first signal during a diagnostic mode in which the motor is deactivated.

12 . A method for operation of a saw with an implement reaction mechanism comprising:
detecting, with an object detection system in the saw, contact between an object other than a work piece and an implement in the saw during operation of the saw; activating, with the object detection system, the implement reaction mechanism in the saw; incrementing, with a controller in the object detection system, a counter in a memory corresponding to a number of times that the implement reaction mechanism has been activated; and disabling, with the controller, operation of the saw in response to the counter exceeding a predetermined threshold.

13 . The method of claim 12 further comprising:
resetting, with an external programming device, the counter in the memory during a maintenance operation; and
enabling, with the controller, operation of the saw in response to the counter being reset.

14 . The method of claim 12 further comprising:
generating, with a user interface device, an output indicating that the saw is disabled and requires service in response to the counter exceeding the predetermined threshold.

Assignees

• Bosch Tool Corp
• Bosch Gmbh Robert

Inventors

• Laliberte Eric
• Szweda Timothy
• Ramaswamy Bharadwaja Marashi
• Krishnarao Niranjan Sathyanarayanarao
• Prabhu Triveni
• Neelaraddi Reshma Hanamanthraddi

Classifications

• B23D45/06 Primary

  with a circular saw blade arranged underneath a stationary work-table · CPC title

• G01R31/343

  in operation · CPC title

• B23D47/08

  of devices for bringing the circular saw blade to the workpiece or removing same therefrom · 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

• B23D45/067

  the saw blade being adjustable according to depth or angle of cut · CPC title