US3789934A - Rotary impact motor - Google Patents

Rotary impact motor Download PDF

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Publication number
US3789934A
US3789934A US00239881A US3789934DA US3789934A US 3789934 A US3789934 A US 3789934A US 00239881 A US00239881 A US 00239881A US 3789934D A US3789934D A US 3789934DA US 3789934 A US3789934 A US 3789934A
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US
United States
Prior art keywords
impact
dog
anvil
hammer
rotation
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
US00239881A
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English (en)
Inventor
K Schoeps
K Karden
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.)
Atlas Copco AB
Original Assignee
Atlas Copco AB
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 Atlas Copco AB filed Critical Atlas Copco AB
Application granted granted Critical
Publication of US3789934A publication Critical patent/US3789934A/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
    • B25B21/026—Impact clutches

Definitions

  • Fie'ld 6 93 7 94 mounted respectively on the hammer and on the impact dog are responsive to relative rotation therebetween for pivoting out the impact dog from the anvil [56] g fizg g gzf Ts to be impacted by the hammer.
  • the impact motor can be given an axially more compact and easily handled embodiment without any critical weakening of the anvil.
  • FIG. 1 is a longitudinal section through an impact motor according to the invention.
  • FIG. 2 is a cross section on the line 2-2 and FIG. 3 a cross section on the line 33 in FIG. 1 with the impact motor in impact position.
  • FIG. 4 is a section corresponding to FIG. 3 but with the impact motor in release position after impact.
  • FIGS. 5 7 show diagrammatically the hammer, the impact body, and the cam body of the impact motor respectively during, after and before the delivery of an impact, the hammer, which is annular in cross section, being cut up for purposes of illustration and shown in a plane development.
  • FIGS. 8 10 are perspective views of respectively an impact dog, a cam body cooperating therewith, and a pin uniting said parts when they are in assembled position thereon.
  • FIG. 11 is a section corresponding to FIG. 3 but with the impact motor in release position just before the delivery of an impact.
  • FIG. 12 finally, is a view taken on the line l2l2 in FIG. 1.
  • the impact clutch is fitted in a hand held impact wrench 15.
  • the wrench 15 comprises a housing 16 having a reversible motor, not shown in the Figures, for example a pneumatically driven one.
  • the motor effects rotation of a drive shaft 17 journalled in the housing 16 selectively in the desired rotational direction.
  • the rotary impact motor proper is mounted between thehousing l6 and afront portion 18 which in a journal bore 19 rotatably supports a forwardly projecting anvil 20.
  • Theforward end of the anvil 20 is a polygonal driving end 21 intended for removably carrying a tool thereon, not shown, usually a socket wrench.
  • the drive shaft 17 is provided with splines 22 which mate with inner splines 23 at the rear end of a hammer 24.
  • the hammer 24 With a cylindrical bore 25 the hammer 24 surrounds in tubular way the rear end of the anvil 20 and is rotatably supported thereon.
  • the hammer 24 is provided with two peripherally spaced or diametrically disposed recesses 26, 27, FIG. 2, opening into the bore 25, and each having a partly cylindrical impact surface 28 and 29, respectively facing in opposite rotational directions of the hammer 24.
  • annular groove 30 reaching to the depth of the recesses 26, 27 and bordered at the rear thereof by an end wall 31 within the hammer 24.
  • the end wall 31 extends from a hub 32 incorporating the splines 23. At the periphery of the hammer 24 the end wall 31 has a peripheral recess and through slot 33 therein, FIG. 12, forming an arc of a circle.
  • the recess and slot 33 opens into the annular groove 30 and receives a pivot 34 which at the forward end thereof carries a cam roller 35 received in the annular groove 30.
  • the hub 32 carries pivotally thereon a holder plate 36 which at a forwardly bent radial shank carries the pivot 34 and by the base portion thereof on the one hand is pivotally carried by the hub 31 and on the other bears against a bearing arranged for the drive shaft 17 in the housing 16.
  • the anvil 20 is provided with a central circular shoulder 38 which is rotatably supported by a cylindrical inner bearing surface 39 in the front portion 18. Behind the shoulder 38 the anvil 20 has a thickened portion 40 which at opposed sides of a peripheral arcuate groove 37, FIG. 2, provides journal ribs for the bore 25 of the hammer 24. Behind the portion 40 the anvil abuts rotatably against the end wall 31 by the end face of a reduced cylindrical end portion 42, FIG. 3. An axial, partly cylindrical recess 43 extends along the anvil 20 through the shoulder 38 and the portions 40, 42. The radius of curvature of the recess 43 is equal to that of the impact surfaces 28, 29.
  • a double-bent torsion spring 45 is inserted in a guiding passage 44 axially obliquely orientated relative to the anvil.
  • the torsion spring 45 is clamped by two angularly bent and laterally protruding shank ends 46, 47 against opposed abutments on a rib 48 disposed in the middle plane of the recess 43 on the end face of the end portion 42.
  • the shank ends 46, 47 project in a radial direction past the rib 48 across the main portion of the partly cylindrical recess 43, FIG. 4.
  • the shank ends 46, 47 are free to pivot in grooves 49, 50 in the end face of portion 42 at both sides of the rib 48.
  • the shank ends 46, 47 are retained in the grooves 49, 50 by the end wall 31 of the hammer 24.
  • an impact dog 51 By a partly cylindrical back 52 an impact dog 51, FIG. 8, is supported and pivotally journalled in the recess 43, the impact dog having an overturned V-shaped guiding shoulder 53 at its forward end and a narrow radial guiding flange 54 at its rear end, both being symmetrical relative to a central plane of symmetry of the 1 impact dog 51.
  • the impact dog In this plane of symmetry the impact dog has a longitudinal axial bore 60 for a pin 55, FIG. 10.
  • a flattened or generally ovoid cam 56 is mounted between a head on the pin 55 and the guiding flange 54 of the impact dog 51, FIG. 9. The cam 56 is pivotally journalled on the pin 55 at a bore 61.
  • the cam 56 is kept pivotally in place in the recess 43 between the guiding flange 54 and the end wall 31.
  • the cam 56 has a pointed cam crest 58 disposed symmetrically in a central plane together with the bore 61 and the spacing lug 57 and is intended for cooperation with the cam roller 35 carried by the hammer 24.
  • the portion of the cam 56 turned away from the cam crest 58 is symmetric with respect to the central plane of the latter.
  • the opposite flattened sides 63, 64 of the ovoid cam 56 are partly cylindrical with the same radius of curvature as the recess 43.
  • the head of the pin 55 and the spacing lug 57 are clamped between or straddled by the shank ends 46, 47 of the torsion spring 45 and are maintained by them in radial alignment with the rib 48 owing to the pre-compression of the torsion spring 45.
  • the impact body 51 and the ovoid cam 56 are biased by the torsion spring 45 to take a central symmetrical position in the anvil 20, FIGS. 4, 11.
  • the radially directed outer face 63 of the impact dog 51 turned away from the part cylinder surface 52 has a radius of curvature substantially equal to the one of the anvil 21 at the cylindrical portion 40 and is concentric with the axis of rotation thereof.
  • the drive shaft 17 rotates the impact motor clockwise when the details thereof in FIG. 1 are viewed in the direction of the arrows 2, 3.
  • the drive shaft 17 rotates the driving end 21 of the anvil which transmits rotation to a socket wrench and a screw, not shown.
  • the parts of the rotary impact motor due to friction will stay in the prevailing position, for example in the position immediately before an impact is delivered as shown in FIG. 11.
  • the drive shaft 17 rotates the hammer 24 via the drive connection splines 22, 23 and the rotation is transmitted to the anvil 20 via the end of the slot 33 trailing with respect to the direction of rotation, FIG.
  • the anvil 20 stops while the directly driven hammer 24 goes on rotating.
  • the cam roller 35 together with the hammer 24 is displaced angularly from the position in FIG. 1 1 in the forward direction to the position in FIGS. 3, 5.
  • the cam roller 35 entrains the crest 58 of the cam 56 and pivots the ovoid cam 56 down in the clockwise direction against the recess 43.
  • the impact is transmitted via the recess 43 to the anvil 20.
  • the cam roller 35 due to the inertia thereof and of the holder 36, continues the rotary movement for a certain distance in the slot 33, FIGS. 4, 6, until friction stops the holder 36.
  • the cam roller 35 thus has left the crest 58, the braced-apart shank ends 46, 47 of the torsion spring 45 can return against the opposed abutment of the rib 48 and the ovoid cam 56 is pivoted up and raised to its symmetrical position together with the impact dog 51, FIGS. 4, 5.
  • the impact dog 51 takes up a release position within the path of rotation of the impact surfaces 28, 29 and with the outer face 63 of the impact dog 51 lying flush with the periphery of the anvil middle portion 40. With the impact dog 51 thus out of the recess 26 and out of the way of the impact surface 28, the hammer is free and starts moving accelerated angularly by the drive shaft 17. This movement continues until the cam roller 35 again hits the crest 58 of the ovoid cam 56, FIG. 7, whereby at the first instant the cam roller 35 is brought to the end of the slot 33 trailing with respect to the rotational direction, FIG.
  • the impact dog 51 is held in position in the recess 43 due to the fact that the guiding shoulder 53 by its tip abuts against the bearing surface 39 on the front portion 18 while the guiding flange 54 of the impact dog 51 by its tip in a similar way abuts against the annular groove of the hammer 24.
  • the guiding flange 54' is disposed axially outside the path of movementof the cam roller and does not hinder the cooperating thereof with the cam crest 58.
  • the impact surfaces 28, 29 of the hammer body 24 have the same radius of curvature as the back portion 52 of the impact dog 51 against the opposed peripheral ends of which they deliver their impacts.
  • a rotary impact motor comprising a rotatable anvil, a hammer rotatably supported in coaxial relation with respect to said anvil, means for rotating said hammer, impact surface means on a portion of said hammer rotatable around said anvil, an impact dog pivotally journalled on said anvil radially inside the path of movement of said impact surface means and about an axis spaced from the axis of rotation of said anvil between an inswung release position within the path of rotation of said impact surface means and an outswung impact position intersecting said path of rotation, biasing means between said anvil and said impact dog for swinging in said impact dog to said release position thereof, and cam means between said hammer and said impact dog responsive to relative rotation therebetween for swinging out said impact dog from said release to said impact position into said path of rotation of said impact surface means.
  • a rotary impact motor according to claim 1 in which said cam means comprise a first cam means on said impact dog and cooperating second cam means mounted on said hammer for swinging out said impact dog to said impact position in same sense of swinging as the sense of rotation of said hammer.
  • a rotary impact motor according to claim 1 in which said biasing means is a torsion spring extending axially of said impact motor, said torsion spring being non-rotatably associated with said anvil for swinging in said impact dog to said release position thereof.
  • a rotary impact motor in which said torsion spring is double shanked and provided with laterally protruding shank ends, opposed abutments on said anvil, a pin supported by said impact dog, and said opposed abutments and pin being resiliently straddled by said shank ends.
  • a rotary impact motor in which said cam means comprise a first cam means pivotally mounted on said pin of said impact dog and cooperating second cam means mounted on said hammer for swinging out said impact dog to said impact position thereof, a lug on said first cam means radially outwardly of said pin, and said lug being resiliently straddled by said shank ends.
  • a rotary impact motor according to claim 1 in which said impact dog is elongated and has a partly cylindrical back, a partly cylindrical axial recess on said anvil member, and said recess being equiform with said back and slidably receiving said impact dog therein for pivotal movement relative to said anvil.
  • a rotary impact motor according to claim 6 in which a radially directed face is provided on said impact dog opposite to said back thereof and concentric with the axis of rotation of said anvil when said impact dog is in the release position thereof.
  • a rotary impact motor comprising a rotatable anvil, a hammer rotatably supported in coaxial relation with respect to said anvil, means for rotating said hammer bidirectionally, a pair of impact surfaces on peripherally spaced portions of said hammer facing oppositely in peripheral direction thereof and rotatable around said anvil, an elongated impact dog pivotally journalled on said anvil about an axis spaced from the axis of rotation of said anvil, said impact dog being pivoted between a release position with the opposed peripheral ends thereof within the path of rotation of said impact surfaces and an impact position with the impact dog pivoted in the same sense as the chosen sense of rotation of said hammer for swinging out one of said ends to intersect said path of rotation, biasing means between said anvil and said impact dog for returning said impact dog to said release position thereof, a first cam means on said impact dog, a second cam means mounted on said hammer and cooperating with said first cam means for pivoting said impact dog to the impact position thereof in response to relative rotation between said hammer
  • a rotary impact motor in which said biasing means is a double shanked torsion spring provided with laterally protruding shank ends, opposed abutments on said anvil, a pin supported by said impact dog, and said opposed abutments and pin being resiliently straddled by said shank ends.
  • said biasing means is a double shanked torsion spring provided with laterally protruding shank ends, opposed abutments on said anvil, a pin supported by said impact dog, and said opposed abutments and pin being resiliently straddled by said shank ends.
  • a rotary impact motor in which said cam means comprise a first cam pivotally mounted on said pin of said impact dog and a cooperating second cam mounted on said hammer for swinging out said impact dog to said impact position thereof, a lug on said first cam radially outwardly of said pin, and said lug being resiliently straddled by said shank ends.
  • a rotary impact motor according to claim 1 in which said impact dog is symmetrical with respect to a central plane therethrough, said central plane in the release position of said impact dog substantially coinciding with a plane through the axis of rotation of the anvil and the pivoting axis of said impact dog.
  • a rotary impact motor in which said impact dog is symmetrical with respect to a central plane therethrough, said central plane in the release position of said impact dog substantially coinciding with a plane through the axis of rotation of said anvil and the pivoting axis of said impact body.
  • a rotary impact motor comprising a rotatable anvil, a tubular hammer supported in coaxial relation rotatably around said anvil, means for rotating said hammer, an elongated impact dog having a partly cylindrical back formed thereon, a partly cylindrical axial recess on said anvil member, said recess being equiform with said back and slidably receiving said back therein for pivotal movement of said impact dog about the cylinder axis of said recess between an inswung release position within the path of rotation of said tubular hammer and an outswung impact position intersecting said path of rotation, a pivot pin on said impact dog between the cylinder axis of the recess and the axis of rotation of said anvil, a cam in said recess flattened relative thereto and pivotally journalled on said pivot pin for normally occupying a central position in said recess, biasing means between said anvil on the one hand and said impact dog and flattened cam on the other for swinging in said impact dog
  • a rotary impact motor in which said impact dog is symmetrical with respect to a central plane therethrough and through said pivot pin, said central plane in the release position of said impact dog defining said central position of said flattened cam and substantially coinciding with a plane through the axis of rotation of said anvil and the cylinder axis of said recess.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
US00239881A 1971-04-07 1972-03-31 Rotary impact motor Expired - Lifetime US3789934A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE04515/71A SE357152B (enrdf_load_stackoverflow) 1971-04-07 1971-04-07

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US3789934A true US3789934A (en) 1974-02-05

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DE (1) DE2216497C3 (enrdf_load_stackoverflow)
SE (1) SE357152B (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4002212A (en) * 1974-10-02 1977-01-11 Atlas Copco Aktiebolag Rotary impact mechanism
EP0105038A1 (en) * 1982-09-24 1984-04-04 Atlas Copco Aktiebolag A hydraulic torque impulse tool
US4557337A (en) * 1981-01-27 1985-12-10 Katushiki Kiisha Kuken Impact wrench
US20150114674A1 (en) * 2013-10-31 2015-04-30 Chuan-Cheng Ho Impact device of pneumatic tool
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US20210379738A1 (en) * 2016-08-25 2021-12-09 Milwaukee Electric Tool Corporation Impact tool
US12115627B2 (en) * 2022-12-12 2024-10-15 Porite Taiwan Co., Ltd. Driving mechanism

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3470010D1 (en) * 1984-01-05 1988-04-28 Kuken Kk An impact wrench
CN108487859A (zh) * 2018-04-02 2018-09-04 李相峰 电力风塔环形基础的施工方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3179219A (en) * 1962-04-02 1965-04-20 Atlas Copco Ab Impact clutches
US3610344A (en) * 1968-09-24 1971-10-05 Atlas Copco Ab Impact clutch
US3648784A (en) * 1969-09-26 1972-03-14 Atlas Copco Ab Rotary impact motor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3179219A (en) * 1962-04-02 1965-04-20 Atlas Copco Ab Impact clutches
US3610344A (en) * 1968-09-24 1971-10-05 Atlas Copco Ab Impact clutch
US3648784A (en) * 1969-09-26 1972-03-14 Atlas Copco Ab Rotary impact motor

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4002212A (en) * 1974-10-02 1977-01-11 Atlas Copco Aktiebolag Rotary impact mechanism
US4557337A (en) * 1981-01-27 1985-12-10 Katushiki Kiisha Kuken Impact wrench
EP0105038A1 (en) * 1982-09-24 1984-04-04 Atlas Copco Aktiebolag A hydraulic torque impulse tool
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US20150114674A1 (en) * 2013-10-31 2015-04-30 Chuan-Cheng Ho Impact device of pneumatic tool
US9636808B2 (en) * 2013-10-31 2017-05-02 Chuan-Cheng Ho Impact device of pneumatic tool
US20210379738A1 (en) * 2016-08-25 2021-12-09 Milwaukee Electric Tool Corporation Impact tool
US11897095B2 (en) * 2016-08-25 2024-02-13 Milwaukee Electric Tool Corporation Impact tool
US20240181609A1 (en) * 2016-08-25 2024-06-06 Milwaukee Electric Tool Corporation Impact tool with collapsible member to compensate for thermal expansion
US12304034B2 (en) * 2016-08-25 2025-05-20 Milwaukee Electric Tool Corporation Impact tool with collapsible member to compensate for thermal expansion
US12115627B2 (en) * 2022-12-12 2024-10-15 Porite Taiwan Co., Ltd. Driving mechanism
US20250001562A1 (en) * 2022-12-12 2025-01-02 Porite Taiwan Co., Ltd. Driving mechanism
US12390910B2 (en) * 2022-12-12 2025-08-19 Porite Taiwan Co., Ltd. Driving mechanism

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Publication number Publication date
DE2216497A1 (de) 1972-10-19
DE2216497C3 (de) 1974-07-04
SE357152B (enrdf_load_stackoverflow) 1973-06-18
DE2216497B2 (enrdf_load_stackoverflow) 1973-12-06

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