(19)
(11) EP 1 238 757 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.03.2005 Bulletin 2005/11

(43) Date of publication A2:
11.09.2002 Bulletin 2002/37

(21) Application number: 02004959.9

(22) Date of filing: 05.03.2002
(51) International Patent Classification (IPC)7: B25B 23/00, B25B 21/02
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 05.03.2001 JP 2001060812

(71) Applicant: MAX CO., LTD.
Chuo-ku, Tokyo (JP)

(72) Inventors:
  • Tanaka, Hiroshi
    Chuo-ku, Tokyo (JP)
  • Tamura, Junichi
    Chuo-ku, Tokyo (JP)

(74) Representative: Turi, Michael, Dipl.-Phys. et al
Samson & Partner Widenmayerstrasse 5
80538 München
80538 München (DE)

   


(54) Pneumatic screwdriver with screwing depth limitation


(57) An automatic stop device for a screwdriver stops the rotation of the air motor of the screwdriver if the desired screwing depht is reached. A screw feed device (15) of the screwdriver comprises a pneumatic cylinder (3). In an air passage (41) formed in the pneumatic cylinder, a valve chamber (47) is formed in order to operate an air exhaust valve (35) to communicate the pilot air chamber (23a) with the open air. An air exhaust hole (46) for exhausting compressed air from the air passage (41) is formed in the valve chamber (47). A timer chamber (50) is formed in the upstream of the valve chamber (47) in the air passage (41). A pressure within the valve chamber (47) increases and the air exhaust valve (35) operates upon the pressure increase and the stop valve (22) is actuated to close by discharging the compressed air from the pilot air chamber (23a) of the stop valve (22), when the piston reaches a position near the lower dead point and the compressed air flows from the air passage (41) to the valve chamber (47) via the timer chamber (50) and the air exhaust hole (46) is closed in synchronism with the operation of the contact arm (18).






Search report