EP0832721A1 - Schlagschrauber - Google Patents

Schlagschrauber Download PDF

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Publication number
EP0832721A1
EP0832721A1 EP97102332A EP97102332A EP0832721A1 EP 0832721 A1 EP0832721 A1 EP 0832721A1 EP 97102332 A EP97102332 A EP 97102332A EP 97102332 A EP97102332 A EP 97102332A EP 0832721 A1 EP0832721 A1 EP 0832721A1
Authority
EP
European Patent Office
Prior art keywords
cylinder
air inlet
rotation
rotor
inlet hole
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97102332A
Other languages
English (en)
French (fr)
Inventor
Yotaro Taga
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0832721A1 publication Critical patent/EP0832721A1/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C13/00—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby
    • F01C13/02—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby for driving hand-held tools or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • B25B21/02—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose with means for imparting impact to screwdriver blade or nut socket
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C20/00—Control of, monitoring of, or safety arrangements for, machines or engines
    • F01C20/04—Control of, monitoring of, or safety arrangements for, machines or engines specially adapted for reversible machines or engines

Definitions

  • the present invention relates to an impact wrench, and more particularly to an impact wrench that provides a larger torque when loosening a threaded member such as a bolt than it provides when tightening the threaded member.
  • Impact wrenches are air driven tools for tightening and loosening threaded members such as bolts and nuts.
  • the motor portion and clutch-hammer portion are designed such that tightening torque and loosening torque are equal to each other.
  • An object of the present invention is to provide an impact wrench which can loosen a threaded member easily through application of a loosening torque that is larger than the tightening torque.
  • the present invention provides an impact wrench which includes a motor portion, a clutch hammer portion, and an anvil portion.
  • the motor portion includes a rotor which is supported within a cylinder for rotation in forward and reverse directions, and a plurality of rotor blades which are radially arrayed so as to be movable in the radial direction.
  • the clutch hammer portion is coupled with a drive shaft of the rotor.
  • the anvil portion which receives a hitting force from the clutch hammer portion so as to rotate.
  • the cylinder is provided with an air inlet hole for forward rotation and another air inlet hole for reverse rotation.
  • air inlet holes penetrate the cylinder in the axial direction and are symmetrically arranged on both sides with respect to the center axis of the cylinder.
  • the cylinder is also provided with an air outlet hole which is formed at a location shifted from the top by an angle ⁇ in a direction toward the air inlet hole for forward rotation.
  • the angle ⁇ is preferably in the range of 10° to 20°.
  • the loosening torque can become larger than the screw tightening torque through a mere shift in the location of the air outlet hole formed in the cylinder.
  • an improved impact wrench which can easily loosen a tightened threaded member is provided by a minimum design change.
  • FIG. 1 compressed air is introduced into an impact wrench 1 through an air inlet 2a of a hose adapter 2 which is screwed into the bottom end of a handle portion 18.
  • a trigger 3 is rotatably attached to the upper part of the handle portion 18.
  • the trigger 3 When the trigger 3 is rotated counterclockwise (the direction indicated by the arrow in the figure) about an axis 3a, the trigger 3 pushes down a trigger pin 19, which in turn pushes down a valve stem 4 which is continuously urged upward by a spring 17 and is in contact with a shoulder portion 18a.
  • the valve stem 4 breaks contact with the shoulder portion 18a, such that compressed air is introduced into an air passage 18b.
  • a reverse valve 6 is supported in a bushing 21, and is slidable in the forward and reverse directions.
  • the bushing 21 is inserted in the lower portion of a motor housing 20.
  • an air hole 21a which communicates with the air passage 18c formed in the handle portion 18.
  • the reverse valve 6 has two smaller diameter portions 6a and 6b in its central region. When the reverse valve 6 is moved to the forward position, the smaller diameter portion 6a moves to the location of the hole 21a in the bushing 21, the compressed air flows, through a passage formed by the smaller diameter portion 6a, into an air passage (not shown) in the motor housing 20, so that the impact wrench is driven in the tightening direction (forward direction).
  • FIG. 2 is an exploded perspective view of the motor portion 8.
  • the motor portion 8 is contained in the motor housing 20 and comprises a rear plate 12, a rotor 13, rotor blades 14a - 14f, a cylinder 15, and a front plate 16.
  • the rotor 13 is provided with a drive shaft 13a and radial grooves 13b which extend in the longitudinal direction of the cylinder 15.
  • a plurality of (e.g. six) rotor blades 14a - 14f are inserted in the grooves 13b so as to be reciprocable in the radial direction of the rotor 13.
  • the front and rear ends of the cylinder 15 are covered by a front plate 16 and a rear plate 12, respectively.
  • a bearing 12b is fixed to the rear plate 12, while another bearing (not shown) is fixed to the front plate 16.
  • Those bearings rotatably support the drive shaft 13a of the rotor 13.
  • Spline teeth 13c are formed on the drive shaft 13a near its end, which faces the clutch hammer portion 10, so that the drive shaft 13a is coupled with a boss portion (not shown) of the clutch hammer portion 10 through fitting.
  • FIG. 3 shows action of the motor portion; specifically, action of the rotor 13, the rotor blades 14a - 14f and the cylinder 15 during forward rotation.
  • compressed air is introduced into the motor portion 8 through a hole 12a formed at the left side of the rear plate 12.
  • the compressed air is introduced into the interior of the cylinder 15 through a forward rotation air inlet hole 15a bored in a crescent-shaped depression 15e formed in the cylinder 15.
  • the rotor 13 is driven forward around the center O indicated by the arrow in FIG. 3.
  • the center O of the rotor 13 is eccentric with respect to the center Oc of the cylinder 15.
  • the compressed air within the active area Wx hatchched area in the FIG.
  • the compressed air is exhausted through the outlet holes 15b which are formed in the cylinder 15 at locations shifted from the top 15d of the cylinder 15 by an angle ⁇ .
  • the outlet holes 15b are preferably arrayed in the axial direction of the cylinder 15, as shown in FIG. 2.
  • FIG. 4 shows action of the motor portion during reverse rotation.
  • the reverse valve 6 When the reverse valve 6 is moved to the rear position, compressed air is introduced into the motor portion 8 through the hole 12a formed at the right side of the rear plate 12.
  • the compressed air is introduced into the cylinder 15 through a reverse rotation air inlet hole 15c bored in a crescent-shaped depression 15f formed in the cylinder 15.
  • the position of the reverse rotation air inlet hole 15c is symmetrical with that of the forward rotation air inlet hole 15a.
  • the rotor 13 is driven reverse around the center O as indicated by the allow in FIG. 4.
  • the compressed air within the active area Wy (hatched area in FIG. 4) related to the two rotor blades 14d and 14e that are exposed to the compressed air produces a rotation driving force.
  • the compressed air is exhausted through the outlet holes 15b.
  • the outlet holes are formed in the cylinder at a location offset from the top of the cylinder by an angle ⁇ in the direction toward the forward rotation air inlet hole. Therefore, the active area Wy for loosening (reverse) rotation is larger than the active area Wx for tightening (forward) rotation, so that the loosening (reverse) torque is larger than the tightening (forward) torque.
  • the angle ⁇ is preferably between 10° and 20°. If the angle ⁇ is smaller than 10°, the active area Wy for reverse rotation may not be sufficiently larger than the active area Wx for forward rotation, and the tightened screw may not be easily loosened with the impact wrench. If the angle ⁇ is larger than 20°, the active area Wx for tightening (forward) rotation may be too small and proper tightening torque may not be obtained.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
  • Percussive Tools And Related Accessories (AREA)
EP97102332A 1996-09-30 1997-02-13 Schlagschrauber Withdrawn EP0832721A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP25826196A JPH10100073A (ja) 1996-09-30 1996-09-30 インパクトレンチ
JP258261/96 1996-09-30

Publications (1)

Publication Number Publication Date
EP0832721A1 true EP0832721A1 (de) 1998-04-01

Family

ID=17317782

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97102332A Withdrawn EP0832721A1 (de) 1996-09-30 1997-02-13 Schlagschrauber

Country Status (2)

Country Link
EP (1) EP0832721A1 (de)
JP (1) JPH10100073A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013178646A3 (en) * 2012-06-01 2014-07-17 Atlas Copco Industrial Technique Ab Reversible pneumatic vane motor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1478904A1 (de) * 1961-06-20 1969-06-04 Gardner Denver Co Drehschlagschrauber
US3951217A (en) * 1974-09-03 1976-04-20 Chicago Pneumatic Tool Company Impact air wrench having a two position pressure regulator
US4418764A (en) * 1981-07-14 1983-12-06 Giken Kogyo Kabushiki Kaisha Fluid impulse torque tool
US4740144A (en) * 1987-05-04 1988-04-26 Dresser Industries, Inc. Reversible radial vane air motor
EP0581431A1 (de) * 1992-07-27 1994-02-02 Ingersoll-Rand Company Druckflüssigkeitsmotor mit einem Leistungsregler

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1478904A1 (de) * 1961-06-20 1969-06-04 Gardner Denver Co Drehschlagschrauber
US3951217A (en) * 1974-09-03 1976-04-20 Chicago Pneumatic Tool Company Impact air wrench having a two position pressure regulator
US4418764A (en) * 1981-07-14 1983-12-06 Giken Kogyo Kabushiki Kaisha Fluid impulse torque tool
US4740144A (en) * 1987-05-04 1988-04-26 Dresser Industries, Inc. Reversible radial vane air motor
EP0581431A1 (de) * 1992-07-27 1994-02-02 Ingersoll-Rand Company Druckflüssigkeitsmotor mit einem Leistungsregler

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013178646A3 (en) * 2012-06-01 2014-07-17 Atlas Copco Industrial Technique Ab Reversible pneumatic vane motor
US9835031B2 (en) 2012-06-01 2017-12-05 Atlas Copco Industrial Technique Ab Reversible pneumatic vane motor

Also Published As

Publication number Publication date
JPH10100073A (ja) 1998-04-21

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