Power tool drop arm with offset ribbing

Patent metadata

Field	Value
Publication number	US-10213853-B2
Application number	US-201615060733-A
Country	US
Kind code	B2
Filing date	Mar 4, 2016
Priority date	Mar 12, 2015
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A power tool assembly includes a drop arm frame with an opening configured to rotatably support an arbor shaft, a lower surface spaced apart from the opening, and a plurality of ribs extending between the lower surface and the opening. The plurality of ribs define a respective one of a plurality of axes, the plurality of axes intersect at a locus, and the locus is adjacent to, but spaced apart from, a center of gravity of the drop arm assembly. The power tool assembly further includes an actuating device configured to transfer a force to the drop arm assembly when the drop arm assembly is at the first drop arm assembly position, and a control system configured to control the actuating device to transfer the force to the drop arm assembly when an unsafe condition is sensed.

First claim

The invention claimed is:

1. A power tool assembly comprising:
a drop arm assembly movable along a drop path between a first drop arm assembly position whereat a portion of a shaping device supported by the drop arm assembly extends above a workpiece support surface and a second drop arm assembly position whereat the portion of the shaping device does not extend above the workpiece support surface, the drop arm assembly including a drop arm frame with
an opening configured to rotatably support an arbor shaft,
a lower surface spaced apart from the opening, and
a plurality of ribs extending between the lower surface and the opening,
wherein the plurality of ribs define a respective one of a plurality of axes, the plurality of axes intersect at a locus, and the locus is adjacent to, but spaced apart from, a center of gravity of the drop arm assembly, such that when the drop arm frame, the locus, and the center of gravity are projected onto a drop plane defined by the drop path, the projected locus and the projected center of gravity are spaced apart by less than a diameter of the opening;

an actuating device configured to transfer a force to the drop arm assembly when the drop arm assembly is at the first drop arm assembly position; and
a control system configured to control the actuating device to transfer the force to the drop arm assembly when an unsafe condition is sensed.

2. The power tool assembly of claim 1 , wherein;
the drop arm assembly moves within the drop plane as it moves along the drop path;
the center of gravity is at least in proximity to the drop plane; and
the drop arm frame includes a semi-spherical strike pin located in the drop plane configured to receive the force transferred by the actuating device.

3. The power tool assembly of claim 2 , further comprising:
a stop pad mounted to the lower surface and configured to cushion the drop arm frame.

4. The power tool assembly of claim 3 , wherein the stop pad is positioned directly outwardly of at least two of the plurality of ribs.

5. The power tool assembly of claim 2 , wherein
the drop arm frame is formed from aluminum, the drop arm assembly further comprising at least one hardened steel pin extending from the drop arm frame; and
the power tool assembly includes an alignment housing configured to receive the at least one hardened steel pin thereby aligning the semi-spherical strike pin with the actuating device.

6. The power tool assembly of claim 5 , wherein the plurality of ribs comprises at least four ribs.

7. The power tool assembly of claim 5 , wherein:
the drop arm frame includes a pair of spaced apart brackets, each bracket including a respective inner bearing wall;
an orbit shaft fixedly mounted to a height adjust carriage;
a first bearing positioned about the orbit shaft and against a first of the respective inner bearing walls;
a second bearing positioned about the orbit shaft and against a second of the respective inner bearing walls;
an orbit bolt threadedly engaging the orbit shaft; and
the orbit shaft and the orbit bolt are configured to compress the first and second bearings against the respective inner bearing walls.

8. The power tool assembly of claim 7 , further comprising:
a stop pad mounted to the lower surface and configured to cushion the drop arm frame.

9. The power tool assembly of claim 8 , wherein the stop pad is positioned directly outwardly of at least two of the plurality of ribs.

10. The power tool assembly of claim 9 , wherein the plurality of ribs comprises at least four ribs.

Assignees

• Bosch Tool Corp
• Bosch Gmbh Robert

Inventors

• Doumani Robert S
• Szweda Timothy
• Talesky Mark S
• Taylor Brian

Classifications

• 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

• B23D47/08

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

• B23D45/067 Primary

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

• B27G19/02

  for circular saws · CPC title

• B27G19/008

  with sensing of human contact or proximity with the blade · CPC title