Oscillating Mechanism for a Power Tool

• US 20160290453A1
• Filed: 12/04/2014
• Published: 10/06/2016
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH, Robert Bosch Tool Corporation (Robert Bosch GmbH)
• Original Assignee: Robert Bosch GmbH
• Inventors: Terrazas, Moreno, Rubens, Jeremy
• Granted Patent: US 10,883,579 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 17/142 with reciprocating saw blades, e.g. with cutting edges at the distal end of the saw blades
• CPC Class Codes: B24B 23/04 with oscillating grinding tools; Accessories therefor
• CPC Class Codes: B24B 27/08 being portable
• CPC Class Codes: B24B 47/12 by mechanical gearing or electric power B24B47/16 takes precedence
• CPC Class Codes: B26B 7/00 Hand knives with reciprocating motor-driven blades
• CPC Class Codes: B27B 19/006 with oscillating saw blades; Hand saws with oscillating saw blades
• CPC Class Codes: B27B 19/008 having a plurality of saw blades or saw blades having plural cutting zones
• CPC Class Codes: F16H 21/52 for interconverting rotary motion and oscillating motion

Abstract

An oscillating power tool includes a drive motor (M) producing rotary motion and an oscillating mechanism (30) for converting the motor rotary motion to an oscillatory side-to-side movement. The oscillating mechanism (30) includes a link (32) driven by an eccentric shaft (16) of the motor (M), a drive arm (40) that drives the hub (45) of the working tool (B) in oscillating motion, and a bearing arrangement (37) between the drive arm (40) and the link (32) that isolates relative rotation and translation between the components while still imparting an oscillatory motion to the drive arm (40).

Claims

1. A power tool comprising:

a drive motor having an eccentric drive shaft;

a tool holder adapted to support a working tool for oscillating rotational motion; and

an oscillating mechanism disposed between said eccentric drive shaft and said tool holder, said oscillating mechanism including;

a link mounted on said eccentric drive shaft for eccentric movement upon rotation of said drive shaft; and

an elongated drive arm having;

a first end coupled to said link in a manner to isolate relative rotation and translation between said link and said drive arm while still imparting an oscillatory motion in one direction to said drive arm; and

a second end engaged to said tool holder to transfer the oscillatory motion to oscillating rotational motion of said tool holder.

2. The power tool of claim 1, wherein:

said link includes an upper link mounted on said eccentric drive shaft and a lower link offset from said upper link, said lower link defining a cylindrical opening; and

said second end of said drive arm is a spherical end slidably disposed within said cylindrical opening to permit relative rotation and axial translation between said drive arm and said lower link.

3. The power tool of claim 2, wherein said lower link includes a cylindrical bushing defining said cylindrical opening.

4. The power tool of claim 2, wherein said lower link includes a roller bearing having a loose fit with a small amount of play between the inner race and the rollers of the bearing, and/or between the rollers and the outer race of the bearing.

5. The power tool of claim 2, wherein said upper link includes a bearing between said upper link and said eccentric drive shaft.

6. The power tool of claim 2, further comprising a counterweight mounted on said eccentric shaft opposite said lower link.

7. The power tool of claim 1, wherein:

said tool holder includes a central hub supporting the working tool; and

said first end of said drive arm includes a threaded shaft extending through said central hub and a threaded nut for engaging the threaded shaft to fix said drive arm to said central hub.

8. The power tool of claim 1, wherein:

said drive motor defines a longitudinal axis;

said eccentric drive shaft includes an eccentric portion offset from said longitudinal axis; and

p1 said link is mounted on said eccentric portion.

9. The power tool of claim 8, wherein:

said eccentric drive shaft includes an end portion aligned with said longitudinal axis, with said eccentric portion between said motor and said end portion; and

the power tool includes a housing defining a bearing support for supporting said end portion of said eccentric drive shaft.

10. The power tool of claim 1, wherein;

the drive motor defines a longitudinal axis;

said tool holder is supported along said longitudinal axis; and

said elongated drive arm is angled between said link and said tool holder.

11. The power tool of claim 1, wherein:

said eccentric drive shaft includes two eccentric portions;

said link is mounted to one of said two eccentric portions; and

a second link is mounted to the other of said two eccentric portions, said second link coupled to a second drive arm for another working tool.

12. An oscillating mechanism for a power tool, the oscillating mechanism engaged between an eccentric drive shaft of the power tool and a tool holder adapted to support a working tool for oscillating rotational motion, the oscillating mechanism comprising:

a link mountable on the eccentric drive shaft for eccentric movement upon rotation of the drive shaft; and

an elongated drive arm having;

a first end coupled to said link in a manner to isolate relative rotation and translation between said link and said drive arm while still imparting an oscillatory motion in one direction to said drive arm; and

a second end engageable to the tool holder to transfer the oscillatory motion to oscillating rotational motion of said tool holder.

13. The oscillating mechanism of claim 12, wherein:

said link includes an upper link mountable on the eccentric drive shaft and a lower link offset from said upper link, said lower link defining a cylindrical opening; and

said second end of said drive arm is a spherical end slidably disposed within said cylindrical opening to permit relative rotation and axial translation between said drive arm and said lower link.

14. The oscillating mechanism of claim 13, wherein said lower link includes a cylindrical bushing defining said cylindrical opening.

15. The oscillating mechanism of claim 13, wherein said lower link includes a roller bearing having a loose fit with a small amount of play between the inner race and the rollers of the bearing, and/or between the rollers and the outer race of the bearing.

16. The oscillating mechanism of claim 13, wherein said upper link includes a bearing mountable on the eccentric drive shaft.

17. The oscillating mechanism of claim 13, further comprising a counterweight mountable on said eccentric shaft opposite said lower link.

18. A power tool comprising:

a drive motor having an eccentric drive shaft;

a tool holder adapted to support a working tool for oscillating rotational motion; and

an oscillating mechanism disposed between said eccentric drive shaft and said tool holder, said oscillating mechanism including;

a link mounted on said eccentric drive shaft for eccentric movement upon rotation of said drive shaft; and

an elongated drive arm having;

a first end coupled to said link in a manner to isolate relative rotation between said link and said drive arm while still imparting an oscillatory motion in one direction to said drive arm; and

a second end engaged to said tool holder to transfer the oscillatory motion to oscillating rotational motion of said tool holder.

19. The power tool of claim 18, wherein:

said link includes an upper link mounted on the eccentric drive shaft and a lower link offset from said upper link, said lower link defining a cylindrical opening; and

said second end of said drive arm is a pivotably mounted within said cylindrical opening to permit relative rotation between said drive arm and said lower link.

20. (canceled)