Power Tool with Improved Belt Tensioning

Patent metadata

Field	Value
Publication number	US-2016263673-A1
Application number	US-201615060754-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 power tool assembly includes an arbor shaft configured to support a shaping device, a belt operably connected to the arbor shaft and configured to rotate the arbor shaft, a motor including a power shaft operably connected to the belt through a motor end pulley, and a positioning device operably connected to the motor, the positioning device configured to rotate the motor about a motor mounting axis of rotation which is offset from an axis of rotation of the motor end pulley, thereby modifying a tension of the belt.

First claim

1 . A power tool assembly comprising:
an arbor shaft configured to support a shaping device; a belt operably connected to the arbor shaft and configured to rotate the arbor shaft; a motor including a power shaft operably connected to the belt through a motor end pulley; and a positioning device operably connected to the motor, the positioning device configured to rotate the motor about a motor mounting axis of rotation which is offset from an axis of rotation of the motor end pulley, thereby modifying a tension of the belt.

2 . The power tool assembly of claim 1 , wherein the positioning device is a spring loaded actuator.

3 . The power tool assembly of claim 1 , wherein the positioning device comprises a jack screw in operable contact with the motor.

4 . The power tool assembly of claim 3 , further comprising a height adjust carriage, wherein:
the motor is rotatably mounted on the height adjust carriage; a plate is fixedly mounted to the height adjust carriage at a location proximate the motor; and the jack screw is threadedly engaged with the plate.

5 . The power tool assembly of claim 4 , wherein;
the motor is mounted on the height adjust carriage using a plurality of slots, the plurality of slots defining the motor mounting axis of rotation.

6 . The power tool assembly of claim 5 , wherein the slots are formed in a gear housing fixedly attached to the motor.

7 . The power tool assembly of claim 6 , further comprising an offset drive shaft operably connected to the motor end pulley, wherein:
the motor includes a power shaft defining a power shaft axis of rotation; and the motor mounting axis of rotation is located below the power shaft axis of rotation and the axis of rotation of the motor end pulley.

8 . The power tool assembly of claim 7 , further comprising:
a belt protective cover positioned above belt, the belt protective cover including a port defined therein, the port configured to provide direct access to the belt from above the power tool assembly.

9 . A method modifying a tension of a belt of a power tool assembly including an arbor shaft configured to support a shaping device, a belt operably connected to the arbor shaft and configured to rotate the arbor shaft, and a motor including a power shaft operably connected to the belt through a motor end pulley, comprising;
rotating the motor about a motor mounting axis of rotation which is offset from an axis of rotation of the motor end pulley using a positioning device, thereby modifying a tension of the belt.

10 . The method of claim 9 , wherein rotating the motor comprises rotating the motor using a positioning device in the form of a spring loaded actuator.

11 . The method of claim 9 , wherein rotating the motor comprises rotating the motor using a positioning device in the form of a jack screw in operable contact with the motor.

12 . The method of claim 11 , wherein rotating the motor comprises:
rotating the jack screw while the jack screw is threadedly engaged with a plate fixedly mounted to a height adjust carriage at a location proximate the motor thereby rotating the motor with respect to the height adjust carriage.

13 . The method of claim 12 , wherein rotating the motor comprises:
rotating the motor about a motor mounting axis of rotation defined by a plurality of slots used to mount the motor to the height adjust carriage.

14 . The method of claim 13 , further comprising:
checking the tension of the belt through a port in a belt protective cover positioned above belt.

15 . The method of claim 14 , wherein the slots are formed in a gear housing fixedly attached to the motor.

16 . The method of claim 15 , wherein rotating the motor about a motor mounting axis of rotation comprises:
rotating the motor about a motor mounting axis of rotation located below a motor power shaft axis of rotation, the power shaft axis of rotation located below the axis of rotation of the motor end pulley.

Assignees

• Bosch Tool Corp
• Bosch Gmbh Robert

Inventors

• Doumani Robert S

Classifications

• B23D47/12 Primary

  of drives for circular saw blades · CPC title

• B23D59/002 Primary

  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

• B23D45/06

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

• B27G19/003

  for chain saws (braking devices B27B17/08) · CPC title