(19)
(11) EP 2 236 249 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
28.12.2011 Bulletin 2011/52

(43) Date of publication A2:
06.10.2010 Bulletin 2010/40

(21) Application number: 10002955.2

(22) Date of filing: 19.03.2010
(51) International Patent Classification (IPC): 
B25D 16/00(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR
Designated Extension States:
AL BA ME RS

(30) Priority: 01.04.2009 JP 2009089461

(71) Applicant: Makita Corporation
Anjo, Aichi 446-8502 (JP)

(72) Inventors:
  • Machida, Yoshitaka
    Anjo Aichi 446-8502 (JP)
  • Yoshikane, Kiyonobu
    Anjo Aichi 446-8502 (JP)
  • Hirayama, Toshiro
    Anjo Aichi 446-8502 (JP)

(74) Representative: Kramer - Barske - Schmidtchen 
Landsberger Strasse 300
80687 München
80687 München (DE)

   


(54) Hammer drill


(57) In a hammer drill (1), a torque limiter includes: a cam ring (14) adjacent to a gear (13), and configured to be provided onto a tool holder (6) so as to be unitarily rotatable with the tool holder (6) and to have cam projections (18) on a surface facing to the gear (13); rollers (21) received in corresponding through-holes (20) formed in the gear (13) and engageable with the cam projections (18) in their rotational directions; and urging means (washer (16) and coil spring (17)) configured to urge the rollers (21) toward the cam ring (14) so that the rollers (21) are brought into engagement with the cam projections (18), and when a torque applied to the tool holder (6) exceeds a setting torque, the rollers (21) pass the cam projections (18) within the through-holes (20) against the urging means and roll on the cam ring (14), so that the gear (13) slips on the cam ring (14) to thereby uncouple the torque transmission to the cam ring (14).







Search report