Diagnostic and maintenance operation for a saw

Patent metadata

Field	Value
Publication number	US-10189098-B2
Application number	US-201615060664-A
Country	US
Kind code	B2
Filing date	Mar 4, 2016
Priority date	Mar 12, 2015
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

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, the generating of the first signal further comprising:
generating, with a current source in the motor, an electrical signal that passes through the brush; and
identifying, with a controller, a level of electrical resistance through the brush with reference to the first signal from the sensor;

identifying, with the controller, a level of wear for the brush with reference to the first signal, the identifying of the level of wear for the brush further comprising:
identifying, with the controller, that the level of wear in the brush exceeds a predetermined threshold in response to the level of electrical resistance being below a predetermined threshold; 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 the predetermined threshold.

2. The method of claim 1 , 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.

3. 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.

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

5. 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, the sensor further comprising:
a current source in the motor configured to generate an electrical signal that passes through the brush; and

the sensor being further configured to:
generate the first signal corresponding to at least one of a level of electrical current or voltage based on the electrical signal that passes through 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 electrical resistance through the brush with reference to the first signal from the sensor;
identify that the level of wear for the brush exceeds a predetermined threshold in response to the level of electrical resistance being below a predetermined threshold; and
operate the user interface device to generate an output requesting replacement of the brush in response to the identified level of wear exceeding the predetermined threshold.

6. The system of claim 5 , the controller being further configured to:
disable operation of the motor in response to the identified level of wear exceeding the predetermined threshold.

7. The system of claim 5 wherein the sensor generates the first signal during a diagnostic mode in which the motor is deactivated.

8. 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.

9. The method of claim 8 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.

10. The method of claim 8 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 Maharshi
• Krishnarao Niranjan Sathyanarayanarao
• Prabhu Triveni
• Neelaraddi Reshma Hanamanthraddi

Classifications

• G01R31/343

  in operation · CPC title

• B23D59/001 Primary

  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

• B23D45/06 Primary

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

• B23D47/08

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

• B23D45/067

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