Vibration reduction apparatus for power tool and power tool incorporating such apparatus

• US 20070017684A1
• Filed: 03/19/2004
• Published: 01/25/2007
• Est. Priority Date: 03/21/2003
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Faatz, Heinz-Werner, Stirm, Micheal
• Granted Patent: US 7,331,407 B2
• Time in Patent Office: Days
• US Class Current: 173/109
• CPC Class Codes: B25D 11/062 comprising a wobbling mechanism, swash plate
• CPC Class Codes: B25D 17/06 Hammer pistons; Anvils ; Guide-sleeves for pistons
• CPC Class Codes: B25D 17/24 Damping the reaction force resiliently mounted handles B25D17/043; dampers in connections of hammers to backhoes E02F3/966
• CPC Class Codes: B25D 2211/061 Swash-plate actuated impulse-driving mechanisms
• CPC Class Codes: B25D 2211/068 Crank-actuated impulse-driving mechanisms
• CPC Class Codes: B25D 2217/0084 being fluid-driven
• CPC Class Codes: B25D 2217/0088 being mechanically-driven
• CPC Class Codes: B25D 2217/0092 being spring-mounted
• CPC Class Codes: B25D 2250/045 Cams used in percussive tools
• CPC Class Codes: B25D 2250/185 Pressure equalising means between sealed chambers
• CPC Class Codes: B25D 2250/221 Sensors
• CPC Class Codes: B25D 2250/231 Sleeve details
• CPC Class Codes: F16F 15/22 Compensation of inertia forces suppression of vibrations of rotating systems by favourable grouping or relative arrangements of the moving members of the system or systems F16F15/20, counterweights F16F15/28; correcting-weights for balancing rotating bodies F16F15/32

Abstract

A vibration reduction apparatus (501) for use with a hammer tool having a hammer piston (520) is shown. The hammer piston (520) is cansed to reciprocate in cylinder (530) by rotation of a gear wheel (523) about axis (524), the hammer piston (520) being mounted to the gear wheel (523) via piston arm (531) and pivot pin (522). Reciprocating motion of the hammer piston causes a flying mass (569) to be driven along cylinder (530) to impart a hammer action to a bit of the tool. The gear wheel (523) is caused to rotate about axis (524) by meshing of gear (514) on drive shaft (511) with gear teeth (532) on the periphery of gear wheel (524), the drive shaft (511) being caused to rotate by a motor (not shown) of the tool. a cam (533) is rigidly mounted around gear wheel (523), a counterweight 5219 surrounds piston cylinder (530), and a cam follower (534) is provided on counterweight 521. The cam follower 534 on counterweight 521 is urged into contact with cam (533) by means of a compression spring (535). The external profile of the cam (533) is such that rotation of gear wheel (534) to cause reciprocating motion of hammer piston (520) causes oscillation of counterweight (521) relative to piston cylinder (530) in antiphase to motion of the hammer piston (520) to counteract vibrations produced by operation of the hammer action of the tool

Claims

1. A vibration reduction apparatus for a power hammer apparatus comprising a housing, a motor arranged in the housing, a piston adapted to be caused by the motor to execute reciprocating motion in a bore, and a flying mass arranged in the bore such that said reciprocating motion of said piston in said bore in use causes reciprocating motion of said flying mass relative to the housing to impart impacts to a working member of the hammer apparatus, the vibration reduction apparatus comprising at least one driveable mass adapted to at least partially surround at least part of the bore, and wherein at least one said driveable mass is adapted to be caused by the motor to execute reciprocating motion to at least partially cancel vibration of said housing caused by reciprocating motion of the flying mass relative to the housing.

2. An apparatus according to claim 1, further comprising at least one driving gear adapted to be driven by said motor to cause said reciprocating motion of said piston and to cause said reciprocating motion of at least one said driveable mass.

3. An apparatus according to claim 2, wherein said vibration reduction means further comprises cam means rotatable by means of at least one said driving gear and adapted to engage at least one said drivable mass.

4. An apparatus according to claim 3, further comprising first biasing means for urging at least one said drivable mass into engagement with said cam means.

5. An apparatus according to claim 3 or 4, further comprising cam follower means for converting rotary motion of said cam means into reciprocating motion of at least one said drivable mass.

6. An apparatus according to claim 5, wherein said first biasing means is adapted to urge at least one said drivable mass into engagement with said cam follower means.

7. An apparatus according to claim 5 or 6, wherein said cam follower means comprises at least one notch adapted to receive a respective projection on at least one said drivable mass.

8. An apparatus according to any one of claims 3 to 7, wherein the or each said driveable mass is adapted to move out of engagement with the cam means when the power hammer apparatus is disengaged from a workpiece.

9. An apparatus according to claim 8, further comprising retaining means for holding the or each said driveable mass out of engagement with said cam means when the power hammer apparatus is disengaged from a workpiece.

10. An apparatus according to claim 9, wherein said retaining means comprises sealing means adapted to act between a working member of said power hammer apparatus and said housing.

11. An apparatus according to any one of the preceding claims, further comprising deactivating means for deactivating said vibration reduction apparatus.

12. An apparatus according to any one of claims 3 to 8 and claim 11, wherein said deactivating means comprises means for disengaging said cam means from said motor.

13. An apparatus according to claim 11 or 12, wherein said deactivating means comprises locking means for locking at least one said driveable mass in position relative to the housing.

14. An apparatus according to any one of the preceding claims, wherein at least one said driveable mass is adapted to be driven by means of air displaced by said flying mass.

15. An apparatus according to any one of the preceding claims, further comprising sensor means for detecting phase and/or amplitude of vibrations produced by said vibration reduction apparatus.

16. An apparatus according to any one of the preceding claims, further comprising adjustment means for adjusting the phase and/or amplitude of vibrations produced by said vibration reduction apparatus.

17. An apparatus according to claims 15 and 16, further comprising control means for controlling said adjustment means in response to said sensor means.

18. An apparatus according to any one of the preceding claims, further comprising at least one support member for supporting at least one said driveable mass, and adapted to be caused by the motor to execute reciprocating motion relative to the housing, wherein at least one said driveable mass is moveable relative to at least one said support member during said reciprocating motion of said driveable mass, and second biasing means for urging at least one said driveable mass into engagement with at least one said support member.

19. An apparatus according to claim 18, wherein at least one said support member comprises a sleeve for at least partly surrounding at least part of said bore.

20. An apparatus according to claim 18 or 19, further comprising damping means for damping impacts between at least one said driveable mass and at least one said support member.

21. An apparatus according to claim 20, wherein at least one said damping means is formed from resilient material.

23. A power hammer apparatus comprising:

—

a housing;

a motor arranged in the housing;

a piston adapted to be caused by said motor to execute reciprocating motion in a bore;

a flying mass arranged in the bore such that said reciprocating motion of said piston in said bore in use causes reciprocating motion of said flying mass relative to said housing to impart impacts to a working member of the power hammer apparatus; and

a vibration reduction apparatus according to any one of the preceding claims.

24. A power hammer apparatus according to claim 23, further comprising a piston cylinder defining said bore.

25. A power hammer apparatus according to claim 24, where at least one said driveable mass is adapted to form at least part of said piston cylinder.

26. A power hammer apparatus according to claim 25, further comprising at least one projection on said piston cylinder for engaging cam follower means of said vibration reduction apparatus.

27. A power hammer apparatus according to claim 26, wherein at least one said projection is provided on an internal surface of said piston cylinder.

28. A power hammer apparatus according to any one of claims 23 to 27, further comprising drive means for causing reciprocating motion of at least one said driveable mass and/or said piston.

29. A power hammer apparatus according to claim 28, wherein said drive means comprises a shaft adapted to be rotated by means of said motor, a drive member having an engaging portion for engaging at least one said driveable mass and/or said flying mass, and a countermass offset from a position diametrically opposite said engaging portion.

22. A vibration reduction apparatus for a power hammer apparatus comprising a housing, a motor arranged in the housing, a piston adapted to be caused by the motor to execute reciprocating motion in a bore, and a flying mass arranged in the bore such that said reciprocating motion of said piston in said bore in use causes reciprocating motion of said flying mass relative to the housing to impart impacts to a working member of the hammer apparatus, the vibration reduction apparatus substantially as hereinbefore described with reference to FIGS. 2 to 19A of the accompanying drawings.

30. A vibration reduction apparatus for a power tool comprising a housing, and a motor in the housing adapted to cause movement of at least one first working member of the tool, the apparatus comprising at least one pair of rotatable masses, the or each said pair comprising respective first and second rotatable masses adapted to be rotated in opposite senses to each other about respective first and second axes of rotation, wherein each of said first and second rotatable masses has a respective centre of mass spaced from the corresponding said axis of rotation.

31. An apparatus according to claim 30, wherein said first and second masses of at least one said pair comprise respective gear wheels.

32. An apparatus according to claim 31, wherein said gear wheels of at least one said pair mesh with each other.

33. An apparatus according to any one of claims 30 to 32, wherein the rotatable masses of at least one said pair are coaxially mounted.

34. An apparatus according to any one of claims 30 to 33, further comprising adjustment means for adjusting the phase and/or amplitude of vibrations produced by said apparatus.

35. An apparatus according to any one of claims 30 to 34, further comprising at least one driving gear adapted to be driven by said motor to cause movement of at least one said first working member and to drive said apparatus.

36. An apparatus according to claims 34 and 35, wherein said adjustment means comprises means for rotating at least one said drive gear relative to at least one said first working member.

37. An apparatus according to claim 35 or 36, wherein said adjustment means comprises means for rotating said masses of at least one said pair relative to each other by a predetermined angle.

38. A power tool comprising:

a housing;

a motor in the housing adapted to cause movement of at least one first working member of the tool; and

a vibration reduction apparatus according to any one of claims 30 to 37.

39. A tool according to claim 38, wherein the motor is adapted to drive at least one said first working member via a said rotatable mass of at least one said pair.

40. A drive member for a power tool having a housing, a motor in the housing, and a working member adapted to be driven by means of the motor, the drive member comprising an engaging portion and at least one countermass, wherein the drive member is adapted to be mounted to a shaft such that rotation of said shaft in use causes reciprocating motion of said engaging portion, and at least one said countermass is located at a position offset from diametrically opposite said engaging portion.

41. A drive member according to claim 40, further comprising an annular body portion adapted to be mounted to a shaft, wherein said engaging portion is elongate and extends from said body portion.

42. A drive member for a power tool having a housing, a motor in the housing, and a working member adapted to be driven by means of the motor, the drive member substantially as hereinbefore described with reference to FIG. 19A of the accompanying drawings.