US3908768A - Rotary impact tool - Google Patents

Rotary impact tool Download PDF

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Publication number
US3908768A
US3908768A US450486A US45048674A US3908768A US 3908768 A US3908768 A US 3908768A US 450486 A US450486 A US 450486A US 45048674 A US45048674 A US 45048674A US 3908768 A US3908768 A US 3908768A
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US
United States
Prior art keywords
hammer
guide housing
housing
stator
rotor
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.)
Expired - Lifetime
Application number
US450486A
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English (en)
Inventor
Johann Hess
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Application granted granted Critical
Publication of US3908768A publication Critical patent/US3908768A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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

Definitions

  • the present invention relates to a rotary impact tool, especially an impact wrench, with an impact'mechanism comprising a coaxially arranged anvil and ham- SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotary impact tool of the aforementioned kind in which the active mass of the striking mechanism is increased by the mass of the rotor.
  • the rotary impact tool mainly comprises a tool housing, drive means in the tool housing and comprising a stator and a rotor surrounding the stator, a pot-shaped guide housing in thetool housing and connected to the rotor for rotation therewith, with the bottom wall of the guide housing rotatably supported on the stator, a hammer arranged in the guide housing for reciprocating movement relative thereto,
  • the aforementioned cooperating means preferably comprise an internal gearing on the guide housing and an external gearing on the hammer meshing with the internal gearing.
  • the drive means is preferably constituted by a vane -motor operated by compressed air and the hollow cylindrical rotor defines with the stator of the vane motor
  • FIG. 1 is a side view of the impact tool partially sectioned along its axis
  • FIG. 2 is a cross-section taken along the lines 2-2 of FIG. 1.
  • the impact wrench has a substantially drumed-shaped tool housing 1 which is provided at its rear portion with adownwardly extending handle 2.
  • the drive for the impact mechanism of the impact wrench is located in the rear portion of the housing 1 and the drive is preferably constituted by a vane motor operated by compressed air.
  • the impact mechanism of the wrench is located in the front part of the housing.
  • the vane motor has an outer tubular rotor 3 which has an inner annular, preferably cylindrical, eccentric reaction surface 6 which surrounds asmall stator 4 which is located coaxially with the rotor.
  • Stator 4 has circumferentially spaced radially extending slots'4a in which vanes 5 are guided for radial reciprocating movement; Springs4b in the bottom portions of the slots 4a, urge the vanes 5 outwardly so that the ends of the vanes 5 are in contact with the eccentric reaction surface 6during rotation of the rotor- 3.
  • the crescentshaped cavity between the annular surface 6 and the outer surface 40 of the rotor is divided by the vanes 5 into working chambers 5a which expand on one side.of a vertical dead-center plane, and contract on the other side thereof to receive and discharge fluid, respectively.
  • the outer surface 40 of the stator is in contact with the inner reaction surface 6 of the rotor along an axial line'located in the dead-center plane of the apparatus which-also passes through the axis of the'rotor 3.
  • the housing portion 1a which closes the tubular housing 1 has a threaded axial bore 31 into which the thread of an extension 3a of the stator 4 is threaded. In this" manner, the central stator 4 is mounted at oneend the housing portion la.
  • the axial ends of the tubular rotor 3 are provided with radial rotor end walls 7 and 7a secured by screws, not shown, to the tubular rotor 3.
  • the axial distance between the confronting faces of the rotor end walls 7 and 7a correspond to the effective axial length of the stator 4 andof the vane 6, a small amount of clearance being provided.
  • the rotor end wall has a central opening through which the extension 312 of the stator 4 projects, forming with the rotor end wall 70 an annular space in which a ball-bearing 32 is located so that the rotor 3 is supported at the respective end for rotation on the extension 3a of the stator.
  • the other end of the stator 4 has a cylindrical extension 8 projecting beyond the other rotor end wall 7, and carrying'aballbearing 9 on which the bottom wall 10 of a pot-shaped hammer guide housing 13 is mounted.
  • the cylindrical outer surface of the bottom wall 10 is closely fitted at 11 into the inner surface of a hollow cylindrical extension l 2 of the rotor 3 and thus supports the latter.
  • guide housing 13 connects the latter for rotation with the rotor 3.
  • the guide housing 13 is turnably mounted by means of a needle bearing 13 in the housing 1.
  • the suply of compressed air to the vane motor takes place through the main valve in the grip portion 2 of the housing operated by a button 33.
  • the two-way shifting valve 34 only schematically shown, supplies the pressure air either to conduit 35 or to conduit 36, depending on the desired direction of rotation of the rotor 3.
  • the pressure air flows into a circular channel 37 closed by circular end face of the rotor end wall 7a, but being swept by an axial conduit 38 in the rotor end wall 7a during rotation of the rotor 3.
  • the air under pressure flows from the pressure conduit 38 into a recess 39 (FIG. 2) of the eccentric reaction surface 6 of the rotor.
  • the recess 39 has a rounded end 39' adjacent the dead-center plane of the vanes 5, as best seen in FIG.
  • the recess 39 is located at the high pressure side formed by expanding working chambers 5a and extends over about one-quarter of the circumference of the inner annular reaction surface 6 of the rotor.
  • the deepest part of the recess 39 has an axial length corresponding to about 30 percent of the axial length of the reaction surface 6, so that the outer edges of the vanes 5 still contact 70 percent of the maximum available surface of the reaction surface 6.
  • another recess 40 is provided at the other end of rotor 3, which is mirror-symmetrical to the dead-center plane, and from which the air is discharged.
  • the rounded ends 39, 40' of the recesses 39, 40 are angularly displaced at an angle of about 40, symmetrically to the deadcenter plane of the vanes 5.
  • Pressure air from the recess 40 enters a conduit portion 41a, communicating with the radial conduit 41 having an annular port 42 which is swept by a conduit portion 43a of a central axially extending conduit 43 which passes along the axis of the stator 4 into the discharge conduit 35 which is con-- transform the energy of the supplied compressed air into a torque acting on the rotor 3.
  • the working chambers 5a are contracted so that the low pressure air is discharged, as explained.
  • the arrangement of the conduit for the pressure air and discharged air has the advantageous result of reducing and damping the noise produced by the apparatus.
  • the hammer guide housing 13 is pot-shaped and is provided at its inner surface therefor with an axially extending internal gearing 14.
  • the internal gearing 14 meshes with an external gearing 15 provided on the outer surface of a hammer 16 located in the interior of the hammer guide housing 13 so that the hammer 16 is constrained to rotate with the guide housing 13 during rotation of the latter, while being axially movable with respect thereto.
  • the hammer 16 carries at a front face thereof circumferentially spaced impact cocks 18 which are adapted to cooperate with corresponding impact cocks 19 on an anvil 20 located forwardly of the hammer 16.
  • the anvil 20 is turnably mounted in a bearing in a front end portion of the housing 1 and projects with a tool head 21 of square or polygonal cross-section beyond the housing on which a tool, for instance a socket wrench may bemounted.
  • a control shaft 22 is coaxially arranged with the impact mechanism formed by the hammer l6 and the anvil 20 and the control shaft 22 is fixed to the anvil 20 for rotation therewith.
  • the control shaft has at its end distant from the anvil 20 a collar 23 with a circumferen'tially extending axially rising and falling cam face 24 engaged by a ball 25 which is guided in an annular cutout and an end face of the hammer 16 which faces the can face 24 of the collar 23.
  • the collar 23 On the face thereof opposite the cam face 24, the collar 23 abuts against an axial roller bearing 26 on the bottom wall 10 of the guide housing 13.
  • An extension 27 of the control shaft 22 is mounted in a slide bearing 28 provided in the bottom wall 10 of the guide housing 13.
  • the spring therewith the hammer 16 are rotated.
  • control shaft 22 connected to the anvil 20 for rotation is taken along through the friction between the hammer l6 and the ball 25, on the one hand and the'ball and the cam surface 24 on the other hand.
  • part of the turning moment imparted to the hammer 16 by the vane motor is also transmitted through the compression spring 29 to the anvil 20.
  • the anvil 20 it rotated together with the hammer 16. If the anvil 20 is now arrested by outside forces, for instance if the nut turned thereby encounters resistance, then the friction connection between hammer and anvil will be overcome so that the hammer 16 will rotate relative to the anvil 20 and the control shaft 22 connected to the latter.
  • the ball 20 will move on the rising portion of the cam face 24 and move thereby the hammer 16 axially towards the left to an active position, as viewed in FIG. 1, so that the cogs 18 and 19 will engage with each other with an impact to thereby tighten the nut. Since the cam face 24 drops again, the cocks l8 and 19 will be brought again out of engagement, where-' after the cycle will be repeated until the turning resistance imparted from outside onto the anvil and the tool connected thereto is overcome.
  • the described construction of the rotor 3 which is connected to the guide housing 13 for rotation is characterized by a very large inertia moment due to the relative large radial distance of the rotating masses from the axis of the tool.
  • said drive means is constituted by a vane motor operated by compressed air, said hollow cylindrical rotor defining with said stator a working space, said stator being provided with a plurality of radially extending slots, and including a plurality of vanes closely guided in said slots and dividing said working space in a plurality of working chambers.
  • control means for reciprocating said hammer during rotation thereof with said guide housing, said control means comprising a control shaft coaxially fixed to said 'anvil for rotation therewith, a collar fixed to said shaft and provided with an axially rising and falling cam face facing the other end of said hammer, a ball riding on 'said cam face, and spring means for pressing said other tend of said hammer against said ball.
  • a ;combination comprising a tool housing; drive means in said housing and comprising a stator and a tubular rotor surrounding said stator; a pot-shaped guide housing in said too] housing, said pot-shaped guide housing having a bottom wall facing said drive means and being rotatably supported on said stator; a hollow cylindrical projection on said rotor extending over said guide housing to support said rotor on said guide housing; a hammer arranged in said guide housing for reciprocating movement relative thereto; and cooperating means on said guide housing and said hammer for connecting the hammer with the guide housing for rotation therewith while permitting axial movement of said hammer relative to said guide housing.
  • bottom wall of said guide housing has a cylindrical outer surface closely fitted in the inner surface of said hollow cylindrical projection.
  • a combination comprising a tool housing; drive means in said housing and comprising a stator and a tubular rotor surrounding said stator; a pot-shaped guide housing in said tool housing and connected to said rotor for rotation therewith, said pot-shaped guide housing having a bottom wall facing said drive means and being rotatably supported on said stator; a hammer arranged in said guide housing for reciprocating movement relative thereto between an active and an inactive position; an anvil turnably mounted on said tool housing adjacent that end of said hammer which is distant from said drive means and cooperating with said hammer to be turned by the latter in said active position; cooperating means on said guide housing and said hammer for connecting said hammer with said guide housing for rotation therewith while permitting axial movement of said hammer relative to said guide housing; control means for reciprocating said hammer during rotation thereof with said guide housing; said control means comprising a control shaft coaxially fixed to said anvil for rotation therewith, a collar fixed

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Drilling And Boring (AREA)
US450486A 1973-03-17 1974-03-12 Rotary impact tool Expired - Lifetime US3908768A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2313402A DE2313402A1 (de) 1973-03-17 1973-03-17 Drehschlagwerkzeug

Publications (1)

Publication Number Publication Date
US3908768A true US3908768A (en) 1975-09-30

Family

ID=5875106

Family Applications (1)

Application Number Title Priority Date Filing Date
US450486A Expired - Lifetime US3908768A (en) 1973-03-17 1974-03-12 Rotary impact tool

Country Status (9)

Country Link
US (1) US3908768A (ja)
JP (1) JPS5714947B2 (ja)
CH (1) CH560582A5 (ja)
DE (1) DE2313402A1 (ja)
FR (1) FR2221240B1 (ja)
GB (1) GB1432322A (ja)
IT (1) IT1046027B (ja)
NL (1) NL175039C (ja)
SE (1) SE419056B (ja)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4243108A (en) * 1977-11-21 1981-01-06 Galimov Anas G Pneumatic inpact wrench having rotatable and axially translatable components
US5083619A (en) * 1989-09-25 1992-01-28 Chicago Pneumatic Tool Company Powered impact wrench
US5172772A (en) * 1991-03-11 1992-12-22 Cooper Industries, Inc. Hydro-impulse screw tool
US5836403A (en) * 1996-10-31 1998-11-17 Snap-On Technologies, Inc. Reversible high impact mechanism
US5944119A (en) * 1998-04-16 1999-08-31 Hsieh; Yu-Fu Grip structure for a pneumatic tool
US6082986A (en) * 1998-08-19 2000-07-04 Cooper Technologies Reversible double-throw air motor
US6135212A (en) * 1998-07-28 2000-10-24 Rodcraft Pneumatic Tools Gmbh & Co. Kg Hammering screwdriver with disengagable striking mechanism
US6158526A (en) * 1999-03-09 2000-12-12 Snap-On Tools Company Reversible impact mechanism with structure limiting hammer travel
US6241500B1 (en) 2000-03-23 2001-06-05 Cooper Brands, Inc. Double-throw air motor with reverse feature
US6318479B1 (en) 1999-10-01 2001-11-20 Chicago Pneumatic Tool Company Vibration isolated impact wrench
US6321853B2 (en) 1999-10-01 2001-11-27 Chicago Pneumtic Tool Company Vibration isolated impact wrench
US6733414B2 (en) 2001-01-12 2004-05-11 Milwaukee Electric Tool Corporation Gear assembly for a power tool
EP1454714A2 (en) * 2003-03-07 2004-09-08 Ingersoll-Rand Company Rotary tool
CN103167935A (zh) * 2010-10-29 2013-06-19 罗伯特·博世有限公司 具有机械式冲击机构的手持式工具机
US20140124228A1 (en) * 2011-06-30 2014-05-08 Atlas Copco Industrial Technique Ab Electric power tool
US20140367132A1 (en) * 2013-06-12 2014-12-18 Panasonic Corporation Impact wrench
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US20160256993A1 (en) * 2013-11-13 2016-09-08 C. & E. Fein Gmbh Oscillatingly Driven Machine Tool
US20210000485A1 (en) * 2013-03-15 2021-01-07 Teleflex Life Sciences Limited Drivers and drive systems

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2543768A1 (de) * 1975-10-01 1977-04-14 Bosch Gmbh Robert Druckluftschlagschrauber
GB2121716B (en) * 1982-06-11 1985-07-31 Coal Ind Hydraulic reciprocating tools
SE438810B (sv) * 1983-10-11 1985-05-13 Vni I P Konstrukt Slaende mutterdragare
US11670977B2 (en) 2019-04-24 2023-06-06 Black & Decker Inc. Outer rotor brushless motor stator mount

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3516769A (en) * 1967-02-10 1970-06-23 Martti Korhonen Rotary vane hydraulic motor
US3639092A (en) * 1968-12-31 1972-02-01 Gaston Sauvaget Apparatus for converting hydraulic or pneumatic energy into kinetic energy or vice versa, such as a rotary multichamber vane-type motor or pumps
US3672797A (en) * 1969-12-10 1972-06-27 Gerlach Brown Inc Fluid power converter

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3414066A (en) * 1966-08-31 1968-12-03 Chicago Pneumatic Tool Co Impact wrench
US3428137A (en) * 1967-10-12 1969-02-18 Chicago Pneumatic Tool Co Impact wrench

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3516769A (en) * 1967-02-10 1970-06-23 Martti Korhonen Rotary vane hydraulic motor
US3639092A (en) * 1968-12-31 1972-02-01 Gaston Sauvaget Apparatus for converting hydraulic or pneumatic energy into kinetic energy or vice versa, such as a rotary multichamber vane-type motor or pumps
US3672797A (en) * 1969-12-10 1972-06-27 Gerlach Brown Inc Fluid power converter

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4243108A (en) * 1977-11-21 1981-01-06 Galimov Anas G Pneumatic inpact wrench having rotatable and axially translatable components
US5083619A (en) * 1989-09-25 1992-01-28 Chicago Pneumatic Tool Company Powered impact wrench
US5172772A (en) * 1991-03-11 1992-12-22 Cooper Industries, Inc. Hydro-impulse screw tool
US5836403A (en) * 1996-10-31 1998-11-17 Snap-On Technologies, Inc. Reversible high impact mechanism
US5944119A (en) * 1998-04-16 1999-08-31 Hsieh; Yu-Fu Grip structure for a pneumatic tool
US6135212A (en) * 1998-07-28 2000-10-24 Rodcraft Pneumatic Tools Gmbh & Co. Kg Hammering screwdriver with disengagable striking mechanism
US6082986A (en) * 1998-08-19 2000-07-04 Cooper Technologies Reversible double-throw air motor
US6217306B1 (en) 1998-08-19 2001-04-17 Cooper Technologies Company Reversible double-throw air motor
US6158526A (en) * 1999-03-09 2000-12-12 Snap-On Tools Company Reversible impact mechanism with structure limiting hammer travel
US6227308B1 (en) 1999-03-09 2001-05-08 Snap-On Tools Company Reversible impact mechanism with structure limiting hammer travel
US6318479B1 (en) 1999-10-01 2001-11-20 Chicago Pneumatic Tool Company Vibration isolated impact wrench
US6321853B2 (en) 1999-10-01 2001-11-27 Chicago Pneumtic Tool Company Vibration isolated impact wrench
US6241500B1 (en) 2000-03-23 2001-06-05 Cooper Brands, Inc. Double-throw air motor with reverse feature
WO2002051596A3 (en) * 2000-12-21 2002-10-17 Chicago Pneumatic Tool Co Vibration isolated impact wrench
WO2002051596A2 (en) * 2000-12-21 2002-07-04 Chicago Pneumatic Tool Company Vibration isolated impact wrench
US6733414B2 (en) 2001-01-12 2004-05-11 Milwaukee Electric Tool Corporation Gear assembly for a power tool
EP1454714A2 (en) * 2003-03-07 2004-09-08 Ingersoll-Rand Company Rotary tool
US20040173364A1 (en) * 2003-03-07 2004-09-09 Ingersoll-Rand Company Rotary tool
US6863134B2 (en) * 2003-03-07 2005-03-08 Ingersoll-Rand Company Rotary tool
EP1454714A3 (en) * 2003-03-07 2006-02-22 Ingersoll-Rand Company Rotary tool
CN103167935A (zh) * 2010-10-29 2013-06-19 罗伯特·博世有限公司 具有机械式冲击机构的手持式工具机
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US10315293B2 (en) * 2011-06-30 2019-06-11 Atlas Copco Industrial Technique Ab Electric power tool
US20140124228A1 (en) * 2011-06-30 2014-05-08 Atlas Copco Industrial Technique Ab Electric power tool
US11737765B2 (en) * 2013-03-15 2023-08-29 Teleflex Life Sciences Limited Drivers and drive systems
US20210000485A1 (en) * 2013-03-15 2021-01-07 Teleflex Life Sciences Limited Drivers and drive systems
US20140367132A1 (en) * 2013-06-12 2014-12-18 Panasonic Corporation Impact wrench
US9975224B2 (en) * 2013-06-12 2018-05-22 Panasonic Corporation Impact wrench
US10093011B2 (en) * 2013-11-13 2018-10-09 C. & E. Fein Gmbh Oscillatingly driven machine tool
US20160256993A1 (en) * 2013-11-13 2016-09-08 C. & E. Fein Gmbh Oscillatingly Driven Machine Tool

Also Published As

Publication number Publication date
FR2221240A2 (ja) 1974-10-11
NL7403519A (ja) 1974-09-19
NL175039B (nl) 1984-04-16
SE419056B (sv) 1981-07-13
CH560582A5 (ja) 1975-04-15
NL175039C (nl) 1984-09-17
GB1432322A (en) 1976-04-14
FR2221240B1 (ja) 1978-03-10
JPS49127278A (ja) 1974-12-05
DE2313402A1 (de) 1974-09-26
JPS5714947B2 (ja) 1982-03-27
IT1046027B (it) 1980-06-30

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