WOBBLE DRIVE FOR AN OSCILLATING TOOL

• US 20140182872A1
• Filed: 12/17/2013
• Published: 07/03/2014
• Est. Priority Date: 12/31/2012
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH, Robert Bosch Tool Corporation (Robert Bosch GmbH)
• Original Assignee: Robert Bosch GmbH
• Inventors: Rubens, Jeremy, Moreno, Jaime
• Granted Patent: US 9,561,569 B2
• Time in Patent Office: Days
• US Class Current: 173/213
• CPC Class Codes: B23Q 5/02 Driving main working members
• CPC Class Codes: B24B 23/04 with oscillating grinding tools; Accessories therefor
• CPC Class Codes: B24B 47/16 performing a reciprocating movement, e.g. during which the sense of rotation of the working-spindle is reversed
• 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

Abstract

An oscillating drive for a power tool includes a wobble shaft located on a drive shaft of a motor for a power tool, and a wobble member rotatably supported on the wobble shaft. The wobble member includes a wobble drive structure that defines a drive axis. A tool driver includes a tool drive structure at one end that is coupled to the wobble drive structure and a tool holder configured to releasably retain an accessory tool. Rotation of the drive shaft causes the wobble shaft to wobble about an axis of the drive shaft. The tool driver holds the wobble member against the rotation of the wobble shaft such that the wobble member wobbles without rotating which results in an oscillating motion of the drive axis of the wobble member in a plane that is parallel to the axis of the drive shaft. The oscillating motion of the drive axis causes the tool driver to oscillate.

Claims

1. A power tool comprising:

a housing including a main body portion and a nose portion, the nose portion defining an opening;

a motor supported in the main body portion of the housing, the motor including an drive shaft that defines a motor axis;

a first wobble shaft located on the drive shaft, the first wobble shaft defining a first wobble axis, the first wobble axis being arranged obliquely with respect to the motor axis;

a first wobble member rotatably supported on the first wobble shaft and including a first wobble drive structure, the first wobble drive structure defining a first drive axis that is substantially perpendicular to the wobble axis; and

a first tool driver moveably supported in the nose portion of the housing, the first tool driver including a first tool drive structure at one end that is coupled to the first wobble drive structure and including a first tool holder at the other end that is located exterior to the housing and is configured to releasably retain an accessory tool;

wherein rotation of the drive shaft causes the first wobble shaft to wobble about the motor axis,

wherein the first tool driver holds the first wobble member against the rotation of the first wobble shaft such that the first wobble member wobbles without rotating which results in an oscillating motion of the first drive axis of the first wobble member in a first plane that is parallel to the motor axis, and

wherein the oscillating motion of the first drive axis causes the first tool driver to oscillate.

2. The tool of claim 1, wherein the first wobble axis, the first drive axis, and the motor axis intersect at a wobble fulcrum point, the wobble fulcrum point defining a center point of oscillation for the oscillating motion of the first drive axis.

3. The tool of claim 2, wherein the first tool driver includes a first spindle portion that is rotatably supported in a passage in the nose portion of the housing for rotational movement about a first spindle axis.

4. The tool of claim 3, wherein the first spindle portion is supported such that the first spindle axis intersects the fulcrum point and is coaxial with the oscillation axis,

wherein the oscillating motion of the first drive axis causes the first spindle portion to rotationally oscillate about the oscillation axis.

5. The tool of claim 4, wherein the first wobble shaft and the first wobble member are configured such that the first wobble axis, the first drive axis, and the motor axis intersect at a position that is offset in front of the first wobble shaft.

6. The tool of claim 4, wherein the first wobble shaft and the first wobble member are configured such that the first wobble axis, the first drive axis, and the motor axis intersect at a position that is offset behind the wobble shaft.

7. The tool of claim 4, further comprising:

a second wobble shaft located on the drive shaft in front of the first wobble shaft, the second wobble shaft defining a second wobble axis, the second wobble shaft being arranged such that the second wobble axis is positioned obliquely with respect to the motor axis; and

a second wobble member rotatably supported on the second wobble shaft and including a second wobble drive structure, the second wobble drive structure defining a second drive axis that is substantially perpendicular to the wobble axis.

8. The tool of claim 7, wherein the second wobble shaft and the second wobble member are arranged such that the second wobble axis and the second drive axis intersect the wobble fulcrum point.

9. The tool of claim 8, wherein the first wobble shaft, the first wobble member, the second wobble shaft, and the second wobble member are configured such that the first wobble axis, the first drive axis, the second wobble axis, and the second drive axis each intersect the motor axis at a common wobble fulcrum point.

10. The tool of claim 9, wherein the wobble fulcrum point is offset in front of the first wobble shaft and offset behind the second wobble shaft.

11. The tool of claim 10, wherein the second wobble shaft and the second wobble member are arranged with respect to the first wobble shaft and the first wobble member such that the oscillating motion of the second drive axis is approximately 180°

out of phase with respect to the oscillating motion of the first drive axis.

12. The tool of claim 11,

wherein the first wobble member includes retaining features in which the second wobble drive structures are moveably retained,

wherein the retaining features hold the second wobble member against the rotation of the second wobble shaft such that second wobble member wobbles without rotating which results in an oscillating motion of the second drive axis in a second plane that is parallel to the first plane.

13. The tool of claim 11, further comprising:

a second tool driver including a second tool drive structure at one end that is coupled to the second wobble drive structure and a second spindle portion that is rotatably supported in a passage defined in the first spindle portion for rotation about the first spindle axis, the second spindle portion including a tool holder at a distal end thereof that is located exterior to the first spindle portion and is configured to releaseably retain an accessory tool;

wherein rotation drive shaft causes the second wobble shaft to wobble about the motor axis,

wherein the second tool driver holds the second wobble member against the rotation of the second wobble shaft such that the second wobble member wobbles without rotating which results in an oscillating motion of the second drive axis of the wobble member in a second plane that is parallel to the motor axis, and

wherein the oscillating motion of the second drive axis causes the second spindle portion to rotationally oscillate about the first spindle axis.

14. The tool of claim 1, wherein the first tool driver extends forwardly from the first wobble member in a direction that is substantially parallel to the motor axis, and

wherein the tool holder of the first tool driver is configured to retain an accessory tool such that the accessory tool oscillates in a plane that is substantially parallel to the motor axis.

15. The tool of claim 15, wherein the first wobble drive structure is positioned with the first drive axis offset from the motor axis and the wobble axis such that the first plane in which the first drive axis oscillates is substantially parallel to and offset from the motor axis, and

wherein the offset position of the first wobble drive structure results in a center point of oscillation of the first drive axis defining an elliptical path in the first plane.

16. The tool of claim 15, wherein the first tool driver includes a spindle portion that defines a spindle axis that lies in the first plane and includes a tool holder at a distal end thereof that is configured to releasably retain an accessory tool, and

wherein the spindle portion is moveably retained in the nose portion of the housing by guide structures, the guide structures configured to allow axial translation and oscillation of the spindle portion in the first plane and prevent movement of the spindle portion in directions transverse to the first plane.

17. The tool of claim 16, wherein the first wobble drive structure includes a pin and the first tool drive structure includes a slot defined in the spindle portion through which the pin extends,

wherein the slot extends for a distance above and below the first plane to provide clearance for the pin to move within the slot in directions perpendicular to the first plane without moving the spindle portion, and

wherein the slot constrains movement of the pin with respect to the slot in directions parallel to the first plane such that movement of the pin in the first plane is transferred to the spindle portion.

18. An oscillating drive for a a power tool comprising:

a wobble shaft located on a drive shaft of a motor for a power tool, the wobble shaft defining a wobble axis, the wobble axis being arranged obliquely with respect to an axis of the drive shaft.

a wobble member rotatably supported on the wobble shaft and including a wobble drive structure, the wobble drive structure defining a drive axis that is substantially perpendicular to the wobble axis; and

a tool driver including a tool drive structure at one end that is coupled to the wobble drive structure and including a tool holder configured to releaseably retain an accessory tool;

wherein rotation of the drive shaft causes the wobble shaft to wobble about the axis of the drive shaft,

wherein the tool driver holds the wobble member against the rotation of the wobble shaft such that the wobble member wobbles without rotating which results in an oscillating motion of the drive axis of the wobble member in a plane that is parallel to the axis of the drive shaft, and

wherein the oscillating motion of the drive axis causes the tool driver to oscillate.