MOTOR-DRIVEN MACHINE TOOL

• US 20090311952A1
• Filed: 02/20/2008
• Published: 12/17/2009
• Est. Priority Date: 04/19/2007
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Zaiser, Adolf
• Granted Patent: US 8,162,727 B2
• Time in Patent Office: Days
• US Class Current: 451/357
• CPC Class Codes: B24B 23/04 with oscillating grinding tools; Accessories therefor
• CPC Class Codes: B24B 27/08 being portable
• CPC Class Codes: B24B 41/042 Balancing mechanisms
• CPC Class Codes: B27B 19/006 with oscillating saw blades; Hand saws with oscillating saw blades

Abstract

A motor-driven machine tool with a drive shaft and a driven shaft on which the tool is received comprises an eccentric coupling device via which the rotational movement of the drive shaft is transmissible onto the driven shaft. A mass balancer shaft is provided for compensating vibrations. Said mass balancer shaft is operatively connected to at least one of the shafts and carries out a compensating movement counter to the eccentric coupling movement.

Claims

1. A motor-driven machine tool, in particular a hand-held power tool (1) comprising a rotatably driveable tool (6), a drive shaft (4) which is driven by a drive unit (2), and an output shaft (5) on which the tool (6) is mounted, it being possible to transfer the rotational motion of the drive shaft (4) via an eccentric coupling device (7) to the output shaft (5),

wherein

a mass-balancing device (10) is provided for oscillation compensation, the mass-balancing device (10) being operatively connected to at least one of the shafts (4, 5) and implementing a compensation motion counter to the eccentric coupling motion.

2. The machine tool as recited in claim 1,

wherein

one component (11) of the mass-balancing device (10) is rotatably supported on the output shaft (5).

3. The machine tool as recited in claim 1,

wherein

one component (11) of the mass-balancing device (10) is supported on a separate balancer shaft (15).

4. The machine tool as recited in claim 3,

wherein

the balancer shaft (15) is held on the housing (14) of the machine tool (1).

5. The machine tool as recited in claim 4,

wherein

the balancer shaft (15) is situated such that it is parallel to and offset from the output shaft (5).

6. The machine tool as recited in claim 1,

wherein

the mass-balancing device (10) includes a mass-balancing member (11) and an eccentric member (12) which is mounted on one of the shafts (4, 5), the mass-balancing member (11) being operatively connected to the eccentric member (12).

7. The machine tool as recited in claim 1,

wherein

the eccentric coupling device (7) includes a coupling member (8) and an eccentric member (9) which is mounted on one of the shafts (4, 5), the coupling member (8) being operatively connected to the eccentric member (9).

8. The machine tool as recited in claim 6,

wherein

the eccentric members are designed as eccentric cams (9, 12) which are fixedly connected to the drive shaft (4), and wherein the coupling member (8) and mass-balancing member (11) bear against the contour of the assigned eccentric cams (9, 12).

9. The machine tool as recited in claim 8,

wherein

the eccentric cams (9, 12) are offset from each other by 180°

relative to the rotational axis (18) of the drive shaft (4).

10. The machine tool as recited in claim 6,

wherein

the coupling member (8) and the mass-balancing member (11) are each fork-shaped in design, the fork tines enclosing the particular eccentric member (9, 12).

11. The machine tool as recited in claim 6,

wherein

the distance between the mass-balancing member (11) and the assigned eccentric member (12) is less than the distance between the coupling member (8) and the assigned eccentric member (9).

12. The machine tool as recited in claim 1,

wherein

the drive shaft (4) and output shaft (5) are situated at an angle to one another.

13. The machine tool as recited in claim 12,

wherein

the coupling member (8) and the mass-balancing member (11) each include an offset contact section (8a, 11 a) which is in contact with the particular eccentric member (9, 12).

14. The machine tool as recited in claim 1,

wherein

the drive shaft (4) and output shaft (5) are situated parallel to one another.

15. The machine tool as recited in claim 1,

wherein

the eccentric coupling device (7) is retained on the output shaft (5) between the tool (6) and the mass-balancing device (10).

16. The machine tool as recited in claim 1,

wherein

the mass-balancing device (10) includes a reciprocating mass part (16) which is displaceably supported in a sliding guide (17) and is acted upon by the eccentric member (12).

17. The machine tool as recited in claim 16,

wherein

the sliding guide (17) makes it possible for the reciprocating mass part (16) to carry out an exclusively translatory displacement motion.

18. The machine tool as recited in claim 16,

wherein

the sliding guide (17) includes a slot link guide having a slot link track (20) and a guide pin which is guided therein.