US3605914A - Rotary impact wrench mechanism - Google Patents

Rotary impact wrench mechanism Download PDF

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Publication number
US3605914A
US3605914A US754824A US3605914DA US3605914A US 3605914 A US3605914 A US 3605914A US 754824 A US754824 A US 754824A US 3605914D A US3605914D A US 3605914DA US 3605914 A US3605914 A US 3605914A
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Prior art keywords
hammer
anvil
impact
dogs
carrier
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US754824A
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English (en)
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Leo Kramer
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Ingersoll Rand Co
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Ingersoll Rand Co
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    • 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
    • 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
    • B25B21/002—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose for special purposes

Definitions

  • a rotary impact wrench clutch mechanism including a rotary anvil adapted to deliver a rotary blow to a fastener, a rotary hammer carrier mounted around the anvil and connected to a motor, and a pair of diametrically opposed hammer dogs pivoted on the carrier to tilt inwardly to strike a blow to the anvil.
  • the clutch mechanism includes a cam operative to tilt the hammer dogs inwardly to strike a blow and then to allow the dogs to pass the anvil without striking a blow during the following rotation of the carrier.
  • the hammer dogs are proportioned and pivoted so that they automatically remain in the non-impact position until they are cammed inwardly and they are returned to the nonimpact position during their rebound by inertial forces following impact with the anvil.
  • the tool clutch is operative in either direction of rotation and includes stop means for automatically preventing the dogs from tilting in the wrong direction in either direction of rotation. During the instant of impact inertial forces hold the hammer dogs against sliding out of engagement with the anvil.
  • This invention relates to a power-operated rotary impact wrench or impact tool for applying rotary or angular impacts to fasteners such as threaded nuts, bolts, etc.
  • this invention relates to a rotary impact tool mechanism for changing the rotating torque of a rotary motor, such as an air-driven motor, to a series of rapid rotary impacts which can be applied to a threaded nut for either driving it tight or for removing it.
  • Pott mechanism One well known impact mechanism used today is known as the Pott mechanism, being named after the inventor who received US. Pat. Nos. 2,012,916, 2,049,- 273 and 2,158,303.
  • a modern version of the Pott mechanism is shown in the US. patent to Jimmerson No. 2,160,150.
  • the hammer is mounted on a shaft driven by a motor and cam balls are mounted between the hammer and the shaft with the cam balls resting in V-shaped grooves formed on the shaft with the cam balls resting in V-shaped grooves formed on the shaft.
  • a coil spring biases the hammer into engagement position with the anvil wherein the cam balls rest in the apexes of their grooves.
  • the Pott mechanism has several disadvantages, one being that when a pair of diametrically opposed hammer dogs are used, the hammer strikes an impact each halfturn which prevents it from gaining sufiicient speed between impacts.
  • a third mechanism is known as the swinging weight mechanism and is disclosed in the US. Pat. No. 2,285,638 to Amtsberg.
  • This mechanism uses a pair of diametrically opposed tilting hammer dogs which rotate around a lobed anvil and are cammed into an impact position with the lobes or jaws on the anvil by engagement with the anvil.
  • the hammer dogs are released by the cams on the anvil immediately before impact and means is provided for applying a drive torque to the dogs to cause them to rotate to a disengaging position following an impact.
  • the swinging weight mechanism has the disadvantage of impacting each half turn of the ham-mer, when two hammer dogs are used, thus preventing the hammer from gaining sufficient speed between impacts. It is desirable to provide a pair of hammer dogs so that the anvil will receive a balanced blow, i.e., a pair of impacts delivered to the opposite sides of the anvil.
  • swinging weight mechanism Another disadvantage of the swinging weight mechanism is that it often rebounds after impact and strikes a blow on its reverse stroke, which is very undesirable, because not only is it inefiicient, but it is acting in the reverse rotary direction.
  • the principal object of this invention is to provide a rotary impact mechanism which overcomes the undesirable features of the foregoing impact mechanisms and, in general, significantly advances the art of rotary impact wrenches.
  • an impact mechanism having a radially tilting hammer dog which automatically tilts to its non-impact position following impact without the application of torque to the pivot of the hammer dog; to provide an impact mechanism having a radially tilting hammer dog which is shaped, proportioned and has a mass which causes the creation of inertia forces that prevent the hammer dog from disengaging during the instant of impact; to provide an impact mechanism which can strike an initial blow which is stronger than the following normal blows; and to provide an impact mechanism having a hammer dog shaped and positioned to create inertial forces acting to move the hammer dog to its non-impacting position relative to the anvil during rebound of the hammer dog following impact with the anvil.
  • a rotary impact mechanism including an anvil carrying a pair of jaws, teeth or detents, a hammer carrier surrounding the anvil and carrying a pair of diametrically opposed tilting hammer dogs.
  • Tht hammer dogs have a middle position where they can rotate around the anvil without engaging it and can be tilted to impact the anvil jaws in either direction of rotation.
  • the hammer dogs are linked together by a yoke means causing them to move in unison and a cam or actuation means cooperating with the anvil and hammer dogs, is operative to tilt the hammer dogs inwardly to their impact positions once, each revolution of the hammer carrier.
  • An automatic stop or limit means prevents them from tilting to the wrong impact position in each direction of rotation.
  • the dogs are proportioned and mounted so that they automatically swing to their non-impact positions following an impact during rebound of the hammer dogs.
  • This automatic return of the hammer dogs to their non-impact positions is caused by inertial forces resulting from the shape, mass and location of the dogs in conjunction with the rebound and subsequent acceleration of the dogs following their impact with the anvil.
  • inertial forces act on the dogs to prevent their disengagement movement which would reduce the efiiciency of the impact energy delivered to the anvil.
  • FIG. 1 is an elevational view of a rotary impact wrench having portions cut away to show the impact clutch of this invention in section;
  • FIGS. 2 to 5 are sections taken on corresponding lines 2-2 to 5--5 in FIG. 1;
  • FIG. 6 is a section taken on line 66 in FIG. 1 except that the hammer dogs are shown in their free or nonimpacting position;
  • FIG. 7 is an axial section taken on line 77 in FIG. 3;
  • FIGS. 8, 9 and 10 are schematic views showing the hammer dog, anvil and cam systems in sequential positions prior to and at the moment of impact;
  • FIGS. 11 to 13 are sequential views showing the hammer dog and anvil during and following impact
  • FIGS. 14 and 15 are schematic views similar to FIGS. 8 to 10 illustrating the components when the impact mechanism is rotated in the opposite direction from that shown in FIGS. 8 to 10;
  • FIG. 16 is a schematic view illustrating the path of the eccentric pin as it moves past the hammer cam tang and the hammer stop pin.
  • the rotary impact wrench 1 shown in FIG. 1 conventionally includes a casing 2 including a nose portion 3, a motor portion 4 and a handle portion 5.
  • the nose portion 3 carries a spindle 6 projecting from its front end
  • the motor portion 4 houses an air motor having a drive shaft 7
  • the handle portion carries an op a i g gg 8 and an inlet connection 9 adapted to be attached to an air hose for feeding air to the motor.
  • the spindle 6 carries flats 10 adapting it to be attached to a conventional wrench socket (not shown). All of the foregoing structure is conventional in the rotary impact wrench art.
  • the motor shaft 7 is connected to the wrench spindle by a novel rotary impact clutch 12 which is the subject of this invention.
  • the clutch 12 includes a hammer 14 rotating around an anvil 15. The hammer 14 is driven by the motor shaft 7 and the anvil 15 is integrally fixed to the spindle 6.
  • the hammer 14 includes a hammer cage or carrier 17 having a rear plate 18, a front plate 19 and a pair of interconntcting braces 20.
  • the rear plate 18 is journaled on a stub shaft 21 at the rear end of the anvil 15. This stub shaft 21 has a reduced diameter.
  • the front plate 19 is journaled on an enlarged annulus 22 provided on the forward portion of the anvil 15. To this point in the description, the hammer cage 17 is free to rotate around the anvil 15.
  • the anvil 15 carries a pair of axially extending fanshaped jaws, teeth, detents or abutments 24 located diametrically opposite each other. These jaws 24 are positioned intermediate the rear and front plates 18 and 19 of the hammer cage 17. In describing the jaws 24 as fan-shaped, it is meant that they project generally radially outward from the anvil 15 with their sides diverging outwardly like a sector of a cylinder. The jaws 24 are adapted to receive rotary impacts or blows from the hammer 14.
  • the hammer cage 17 carries a pair of arcuate shaped hammer dogs 25 tiltably mounted on longitudinal pivot pins 26 extending between the rear and front plates 18 and 19 of the cage 17.
  • the hammer dogs 25 are located at opposite diametrical locations in the cage 17 with the cage braces 20 positioned degrees from the pivot pins 26 so the dogs 25 are free to tilt without interference with the braces 20.
  • the hammer dogs 25 carry radially diverging end surfaces 27 adapted to substantially conform to the jaws 24 on the anvil 15 so that they can tilt inwardly as shown in FIG. 5 and engage the jaws 24, to strike an impact or rotary blow to the anvil 15. It will be noted that the surfaces 27 have a slight arcuate curve.
  • the hammer dogs 25 have three positions including a midposition as shown in FIG. 6, wherein the hammer 14 can rotate freely around the anvil without the dogs 25 striking a blow, a clockwise impact position, as shown in FIG. 3, wherein the dogs 25 tilt forwardly and inwardly to strike a blow in the clockwise rotary direction and a counterclockwise direction wherein they tilt forwardly and inwardly in the counterclockwise direction.
  • the rear plate 18 of the cage 17 is cruciform-shaped and has a pair of larger diametrically extending arms 29 which carry the hammer dog pins 26.
  • a driver fork 30 is keyed to the motor shaft 7 and includes fingers 31 projecting longitudinally forward between the cruciform-shaped projections of the rear plate 18 of the hammer cage 17.
  • the fingers 31 are positioned to engage the side edges of the large arms 29 on the cage rear plate 1 8 to drive the hammer 14.
  • the fingers 31 are spaced to provide an amount of lost motion between the driver fork 30 and the hammer 14.
  • Each finger 31 of the driver fork 30 carries a stop pin 32, as shown in FIG. 7, projecting forward from the end of the finger 31 and adapted to engage against a shoulder 33, shown in FIG. 8, provided on the end of a hammer dog 25 to prevent the dog from tilting in the Wrong direction when rotating in a given direction.
  • the lost motion of the driver fork 30 on the hammer 14 allows the pins 32 to move from one stop position to another relative to the hammer dogs 25 when the rotation of the hammer 14 is reversed.
  • the hammer dogs 25 are interconnected by a barshaped yoke 35 having its middle pivoted on the stub shaft 21 at the rear end of the anvil 15 and having diametrically extending arms carrying yoke pins 36.
  • yoke pins 36 are straddled by bifurcated tongues 37 which are fixed to and project inwardly from the hammer dogs 25.
  • the yoke 35 holds or locks the hammer dogs 25 in identical positions.
  • the yoke 35 can be pivoted to move the hammer dogs 25 to their impact position. This movement is accomplished by a unique cam system.
  • the middle of the anvil carrying the jaws 24 is joined or interconnected to the rear end stub shaft 21 by an anvil eccentric 39.
  • An eccentric ring 40 is journaled on the anvil eccentric 39 and carries a pair of eccentric cam pins 41 located at diametrically opposed positions and projecting rearwardly into the circular path of the yoke 36.
  • One side of the yoke 35 carries a pair of hookshaped cams 44 located near the opposite ends of the yoke 35.
  • the hammer cage rear plate 18 carries a hammer cam tang 45 projecting forward into the circular path of the yoke 35 and the eccentric cam pins 41.
  • the entire cam system rotates with it.
  • the eccentric ring 40 rotates, it also orbits eccentrically around the hammer axis. This eccentric movement will eventually cause the cam pins 41 to engage between an edge of the hammer cam tang 45 and a hook cam 44 on the yoke 35 forcing the yoke 35 to tilt the hammer dogs forwardly and inwardly to an impact position.
  • the eccentric 39 is positioned so that this tilting of the hammer dogs 25 will occur as they near the jaws 24 on the anvil 15.
  • FIGS. 8, 9 and 10 illustrate the operation of the cam system.
  • FIG. 8 shows a hammer dog 25 in its non-impact position passing over one of the anvil jaws 24 and about 100 degrees from its position of impact with the opposite anvil jaws 24.
  • one of the eccentric pins 41 is beginning to engage a hook-shaped yoke cam 44 while the other eccentric pin 41 is engaging the hammer cam tang 45.
  • Both of the eccentric pins 41 must engage their respective cam surfaces 44 and 45 before they can apply any force in moving the hammer dogs 25 inwardly to their impact positions.
  • FIG. 9 shows the hammer dog 25 about 30 degrees from its position of impact with the anvil jaw 24. At this time the hammer dog is tilting inwardly toward an impact position. This tilting movement is caused by the stationary eccentric 39 forcing the eccentric ring 40 to translate to the left (as shown in FIG. 9) of the hammer axis 47 which forces the yoke 35 to rotate counterclockwise relative to the hammer dog a slight amount which is sufficient to tilt the dog 25 inwardly.
  • the cam 44 is contoured so as to stop the relative movement of the yoke 35 and the hammer cam tang 45 releases its eccentric pin 45 so that the yoke 35 is free from the application of further tilting forces.
  • the moment of release is selected so that the hammer dog 25 is still tilting inwardly and will continue tilting inwardly until just before it strikes the anvil jaw 24 as shown in FIG. 10. In this way, the hammer dog 25 cannot begin tilting outwardly prior to impact with the anvil 15.
  • the eccentric pins 41 are disengaged from the hook-shaped yoke cam 44 and the hammer cam tang 45 so that the hammer dog 25 is free to tilt outward following impact.
  • the hammer cage rear plate 18 carries a stop pin 48 located outwardly of the hammer cam tang 45 to prevent the eccentric ring 40 from rotating past the hammer cam tang 45 to the other side of the hammer cam tang during rebound of the hammer dog 25 following impact.
  • the hammer dog 25 is shaped and sized so that the surface 27 will not lock against the anvil jaw 24 in case the tool motor is started when these surfaces are in engagement. This is accomplished by sizing the hammer so that the engagement line of force action between the hammer dog surface 27 and the anvil jaw will extend radially outward from the axis of the pivot pin 26. This force line is shown in FIG. 10 as dotted line 50 and is normal to the line of engagement between the hammer dog surface 27 and the anvil jaw 24.
  • This engagement force line 50 is called a non-locking force line.
  • the inertial forces of the hammer dog 25 form a resultant force acting forwardly through the center of percussion 49 of the hammer dog 25 at the moment of impact.
  • This resultant force acting through the center of percussion 49 is strong enough at the instant of impact to overcome the force of engagement acting along the force engagement line 50 and the torque force delivered by the pivot pin 26 to form a force couple tending to tilt the hammer dog 25 further inwardly toward its impact position.
  • This force couple is illustrated in FIG. 10 and is the combination of the resultant force acting through the center of percussion 49 and the moment arm of the resultant force relative to the axis of the hammer dog 25.
  • the mass and proportions of the hammer dog 25 are such that will provide a sufficient resultant inertial force to prevent the hammer dog 25 from disengaging during impact.
  • FIGS. 11, 12 and 13 illustrate the sequence of movement of the hammer dog 25 following impact.
  • FIG. 11 shows the hammer dog 25 at the moment of impact.
  • FIG. 12 shows the hammer dog 25 during its rebounding movement in a counterclockwise direction.
  • the hammer dog 25 is driven backwardly or rearwardly in a counterclockwise direction, as a result of the resiliency of the elements placed under stress by the impact.
  • These elements will include the anvil 15, the socket (not shown) attached to the spindle 6 and the fastener being driven by the wrench 1.
  • the motor is applying a clockwise torque force to the hammer dog 25 attempting to slow down its rebounding travel and eventually to drive it forwardly in the clockwise direction.
  • the combination of these actions forms a force couple tending to tilt the hammer dog 25 radially outward to its non-impact position. This force couple is explained as follows.
  • This force couple continues to act on the hammer dog during its rebound and after it begins moving forward again.
  • the hammer dog 25 stops moving rearwardly, in the counterclockwise direction its inertial forces resist acceleration by the pivot pin 26 to continue creating the same force couple.
  • This force couple causes the hammer dog 25 to complete its outward tilting movement to its non-impact position well before the leading end 27 of the hammer dog 25 approaches and passes the anvil jaw 24 as shown in FIG. 13 so that the hammer dog 25 is free to pass the anvil jaw 24 without again engaging it.
  • the hammer dog 25 will rotate one full turn about the anvil 15 before again impacting the anvil 15. This action is due to the fact that the cam system will only tilt the dogs 25 inwardly to their impact position once during each revolution of the hammer 14.
  • the hammer 14 can rebound two full turns before striking an impact in the reverse direction. Since the maximum rebound of a rotary impact tool is normally less than a one-half turn, this mechanism will never strike a reverse blow during rebound.
  • FIG. 14 shows the eccentric pin 41 clearing the stop pin 48 during its first revolution in the counterclockwise direction.
  • FIG. 16 illustrates the path of the eccentric pin 41 betwen its position shown in FIG. 10 and the position shown in FIG. 15, when the hammer dog 25 strikes an impact to the anvil 15. After eccentric pin 41 clears the stop pin 48, it is captured in the concave rear side of the hammer tang 45 for a portion of the travel of the hammer 14. Finally, after the hammer rotates about one revolution, the eccentric pin will move to the left of the hammer tang 45, as shown in FIG. 16, wherein it can operate to tilt the hammer dog 25 into impact position during the next revolution of the hammer 14.
  • One advantage of the requirement of two turns before striking the first impact blow is that the motor can accelerate the hammer to a higher speed to create a stronger first blow. This action can be useful in removing fasteners when a very strong first blow is necessary to start moving the fastener. If the first blow does not move the fastener, an operator can again reverse the motor to rotate a few turns in the opposite direction and then reverse it to obtain another strong blow. This operation can be performed again and again when necessary. The point is that the wrench is capable of providing a much stronger blow than its normal blow or impact, and that this capability is useful at times.
  • An impact mechanism comprising:
  • a rotary carrier adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a jaw
  • a hammer dog movably mounted on said carrier adjacent said anvil and movable radially inwardly from a first position wherein it clears said anvil jaw as the carrier rotates around said anvil to a second position wherein it will engage and strike a blow to said anvil jaw;
  • actuation means interconnected between said anvil and hammer dog for moving said hammer dog inwardly to said second position to strike an impact blow to said anvil, said means allowing said hammer dog to pass said anvil jaw without engaging it during a portion of the rotation of said carrier following the striking of a blow.
  • said anvil carries a second jaw which is circumferentially spaced from said first jaw and said actuation means allows said hammer dog to pass said second jaw without striking it following an impact with said first jaw.
  • An impact mechanism comprising:
  • a rotary carrier rotatably mounted on an axis and adapted to be driven;
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw
  • a hammer dog pivoted on said carrier adjacent said anvil and movable radially inwardly from a first position wherein it clears said anvil jaw as it rotates around said anvil to a second position wherein it will engage and strike a blow to said anvil jaw;
  • actuation means interconnected between said anvil and hammer dog for swinging said hammer dog inwardly to said second position to strike an impact blow to said anwil, said means allowing said hammer dog to pass said anvil jaw without engaging it during a portion of the rotation of said carrier following the striking of a blow.
  • a rotary impact tool clutch mechanism comprising:
  • a rotary hammer carrier adapted to be driven by a rotary motor
  • an anvil rotatably and coaxially mounted adjacent said hammer carrier and having a pair of diametrically opposed jaws
  • a pair of hammer dogs movably mounted on said hammer carrier on the opposite sides of the hammer carrier axis and adapted to move inwardly to strike simultaneous impact blows to said jaws on said anvil;
  • actuation means interconnected between said anvil and hammer dogs for automatically moving said hammer dogs inwardly as they approach said anvil jaws to strike said impact blows, said means allowing said hammer dogs to pass said anvil jaws without engagement on the next time they approach said anvil jaws following the striking of said impact blows.
  • a rotary impact tool clutch mechanism comprising:
  • a rotary hammer carrier adapted to be driven by a rotary motor
  • an anvil rotatably and coaxially mounted adjacent said hammer carrier and having a pair of diametrically opposed jaws
  • a pair of hammer dogs pivotably mounted on said hammer carrier on the opposite sides of the hammer carrier axis and adapted to pivot inwardly to strike simultaneous impact blows to said jaws on said anvil;
  • actuation means interconnected between said anvil and hammer dogs for automatically pivoting said hammer dogs inwardly as they approach said anvil jaws to strike said impact blows, said means allowing said hammer dogs to pass said anvil jaws without striking impact blows during a portion of the rotation of the carrier following the striking of said impact blows.
  • said anvil is surrounded by said carrier.
  • said hammer dogs are pivoted on axes which extend parallel to the rotation axis of said hammer carrier.
  • said hammer dogs have non-impact positions wherein said hammer carrier can rotate around said anvil without said hammer dogs engaging said anvil.
  • said hammer carrier includes front and rear plates journaled on portions of said anvil.
  • An impact mechanism comprising:
  • a carrier rotatably mounted on an axis and adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw
  • a hammer dog pivoted on said carrier adjacent to said anvil and tiltable between a middle and first position wherein it clears said anvil jaw as it rotates around said anvil, a second position wherein it will engage and strike a blow to said anvil jaw as said carrier rotates in a clockwise direction and a third position wherein it will engage and strike a blow to said anvil jaw as said carrier rotates in a counterclockwise direction;
  • said limit means also serves to drive said carrier.
  • said limit means is operative to prevent said hammer dog from swinging to said second position when said carrier is driven in a counterclockwise direction.
  • said limit means engages said carrier and includes a stop means adapted to engage said hammer dog to prevent the hammer dog from moving to said second or third positions depending upon the direction of rotation of said carrier.
  • said limit means is a driver which engages said carrier for driving it in a manner providing a limited amount of rotary lost motion between said driver and said carrier, whereby said stop means will move between two different positions relative to said carrier depending on the rotary driving direction of said driver.
  • said driver includes a pair of circularly spaced stop pins moving to alternate positions relative to said hammer dog in opposite driving directions of the carrier.
  • An impact wrench mechanism comprising:
  • a carrier rotatably mounted on an axis and adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw with an impact surface
  • a hammer dog pivoted on said carrier on an axis extending substantially parallel to said carrier axis adjacent to said anvil and tiltable radially inward from a non-impact position to an impact position to engage said anvil jaw as said carrier rotates, said hammer dog having an impact surface adapted to impact said anvil jaw impact surface, and said hammer dog being positioned, proportioned and having a mass and a center of percussion location which will cause the creation of a resultant inertial force couple acting on said hammer dog during the rebound of said hammer dog and carrier following an impact which will urge said hammer dog to tilt outwardly to its non-impact position and to remain in that position as the carrier begins rotation forward.
  • the impact mechanism of claim 16 including:
  • a second hammer dog similar to the first hammer dog pivoted on said carrier diametrically opposite said first hammer dog and a second jaw similar to the first jaw located on said anvil diametrically relative to said first jaw.
  • An impact mechanism comprising:
  • a carrier rotatably mounted on an axis and adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw
  • a hammer dog pivoted on said carrier adjacent said anvil and tiltable between a middle and first position wherein it clears said anvil jaw as it rotates around said anvil, a second position wherein it will engage and strike a blow to said anvil jaw as said carrier rotates in a clockwise direction and a third position wherein it will engage and strike a blow to said anvil as said carrier rotates in a counterclockwise direction;
  • actuation means interconnected between said anvil and hammer dog and operative to tilt said hammer dog to said second position when said carrier is driven in a clockwise direction to cause said hammer dog to strike an impact blow to said anvil jaw.
  • said actuation means is operative to tilt said hammer dog to said third position when said carrier is driven in a counterclockwise direction to cause said hammer dog to strike an impact blow to said anvil jaw.
  • a rotary impact tool clutch mechanism comprising:
  • a rotary hammer carrier adapted to be driven by a rotary motor
  • an anvil rotatably and coaxially mounted within said hammer carrier and having a pair of diametrically opposed jaws
  • a pair of hammer dogs pivotably mounted on said hammer carrier on the opposite sides of the hammer cage axis and adapted to pivot inwardly to strike simultaneous impact blows to said jaws on said anvil;
  • cam means interconnected between said anvil and hammer dogs for automatically pivoting said hammer dogs inwardly as they approach said anvil jaws to strike said impact blows, said cam means allowing said hammer dogs to pass said anvil jaws without striking impact blows during a portion of the rotation of the carrier following the striking of said impact blows and including a link member interconnecting said hammer dogs together for simultaneous rotation.
  • said cam means includes a cam surface on said anvil and interconnecting means interconnecting said cam surface to surfaces on said carrier and said link member to pivot said hammer dogs inwardly to impact position.
  • said interconnecting means rotates on said anvil surface.
  • said cam surface is an eccentric fixed on said anvil and said interconnecting means is a ring journaled on said eccentric.
  • said link member is journaled on said anvil and rotates with said hammer dogs.
  • said ring journaled on said eccentric is disengaged from said surfaces on said carrier and said link member after said hammer dogs are pivoted inwardly and before said hammer dogs engage said jaws.
  • An impact mechanism comprising:
  • a carrier rotatably mounted on an axis and adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw
  • a hammer dog pivoted on said carrier adjacent said anvil and tiltable between a middle and first position wherein it clears said anvil jaws as it rotates around said anvil, a second position wherein it will engage and strike a blow to said anvil jaw as said carrier rotates in a clockwise direction and a third position wherein it will engage and strike a blow to said anvil as said carrier rotates in a counterclockwise direction;
  • actuation means interconnected between said anvil and hammer dog and operative to tilt said hammer dog to said second position when said carrier is driven in a clockwise direction to cause said hammer dog to strike an impact blow to said anvil jaw at least once each complete revolution of said carrier;
  • said actuation means being operative to allow said car rier to rotate more than one revolution before striking an impact when initially reversed after rotating in the opposite direction, thus enabling said hammer dog to strike an initial impact which is substantially more powerful than its normal impact.
  • An impact wrench mechanism comprising:
  • a carrier rotatably mounted on an axis and adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw
  • a hammer dog pivoted on said carrier on an axis extending substantially parallel to said carrier axis adjacent to said anvil and tiltable radially inward to engage said jaw as said carrier rotates, said hammer dog being positioned and shaped so that it impacts said jaw generally along a force line displaced radially outward from the axis of the hammer dog pivot causing the creation of a camming force acting on the hammer dog tending to cause it to tilt outwardly to disengage said jaw during said impact, and said hammer dog being also positioned, proportioned and having a mass and a mass center location which will cause the creation of inertia forces acting on said hammer dog during the instant of said impact which will overcome said camming force and will prevent said hammer dog from tilting outwardly during the instant of impact.
  • An impact wrench mechanism comprising:
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw with an impact surface
  • a hammer dog pivoted on said carrier on an axis extending substantially parallel to said carrier axis adjacent to said anvil and tiltable radially inward to engage said jaw as said carrier rotates, said hammer dog having an impact surface adapted to engage said anvil jaw impact surface, the impact surfaces of said hammer dog and anvil jaw being shaped so that during the impact of said hammer dog with said anvil, a camming force is created acting on the hammer dog tending to cause it to tilt outwardly to disengage said jaw during said impact, and said hammer dog being also positioned, proportioned and having a mass and a mass center location which will cause the NILE C. BYERS, ]R.,
  • An impact wrench mechanism comprising:
  • a carrier rotatably mounted on an axis and adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw with an impact surface
  • a hammer dog pivoted on said carrier on an axis extending substantially parallel to said carrier axis adjacent to said anvil and tiltable radially inward to engage said jaw as said carrier rotates, said hammer dog having an impact surface adapted to engage said anvil jaw impact surface, the impact surfaces of said hammer dog and anvil jaw being shaped so that during the impact of said hammer dog with said anvil, a camming force is created acting on the hammer dog tending to cause it to tilt outwardly to disengage said jaw during said impact, and said hammer dog being also positioned, proportioned and having a mass and a center of percussion location which will cause the creation of a resultant inertial force couple acting on said hammer dog during the instant of said impact which will prevent said hammer dog from tilting outwardly during the instant of impact.
  • An impact wrench mechanism comprising:
  • a carrier rotatably mounted on an axis and adapted to be driven
  • an anvil rotatably and coaxially mounted adjacent said carrier and having a radially projecting jaw with an impact surface
  • a hammer dog pivoted on said carrier on an axis extending substantially parallel to said carrier axis adjacent to said anvil and tiltable radially inward to engage said jaw as said carrier rotates, said hammer dog having an impact surface adapted to engage said anvil jaw impact surface, the impact surfaces of said hammer dog and anvil jaw being shaped so that during the impact of said hammer dog with said anvil, a camming force is created acting on the hammer dog along a force line located relative to the hammer dog axis to cause it to tilt outwardly to disengage said jaw during said impact, and said hammer dog being also positioned, proportioned and shaped to have a center of percussion location which provides a greater moment arm about said hammer dog axis for an inertial force opposing said camming force and acting through said center of percussion than the moment or of said camming force about said hammer dog axis.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
US754824A 1968-08-23 1968-08-23 Rotary impact wrench mechanism Expired - Lifetime US3605914A (en)

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US75482468A 1968-08-23 1968-08-23

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US3605914A true US3605914A (en) 1971-09-20

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US754824A Expired - Lifetime US3605914A (en) 1968-08-23 1968-08-23 Rotary impact wrench mechanism

Country Status (6)

Country Link
US (1) US3605914A (de)
BE (1) BE737849A (de)
DE (1) DE1939262C2 (de)
FR (1) FR2016255A1 (de)
GB (1) GB1231732A (de)
SE (1) SE374880B (de)

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5199505A (en) * 1991-04-24 1993-04-06 Shinano Pneumatic Industries, Inc. Rotary impact tool
US5435398A (en) * 1994-09-01 1995-07-25 Chiu-Yu Wang Cheng Electrical wrench
EP0808694A1 (de) 1996-05-21 1997-11-26 Yotaro Taga Schalldämpfereinrichtung zur Verwendung in einem Schlagschrauber
US5740892A (en) * 1996-08-26 1998-04-21 Huang; Chen Shu-Hsia Power wrench torque transmission mechanism
US5784934A (en) * 1997-01-30 1998-07-28 Shinano Pneumatic Industries, Inc. Ratchet wrench with pivotable head
US5887666A (en) * 1997-08-04 1999-03-30 Chen; Kenneth Impact wrench structure
USD434298S (en) * 1999-12-06 2000-11-28 S.P. Air Kabusiki Kaisha Impact wrench
US6311583B1 (en) 2000-04-13 2001-11-06 S. P. Air Kabusiki Kaisha Ratchet wrench with pivotable head
US6443239B1 (en) 2000-02-29 2002-09-03 S.P. Air Kabusiki Kaisha Pneumatic rotary tool
US6491111B1 (en) 2000-07-17 2002-12-10 Ingersoll-Rand Company Rotary impact tool having a twin hammer mechanism
US20040159451A1 (en) * 2003-02-14 2004-08-19 Koji Taga Air intake and exhaust device for a pistol type air impact wrench
US20050022638A1 (en) * 2003-07-30 2005-02-03 Rodney Milbourne Impact wrench having an improved anvil to square driver transition
US6938526B2 (en) 2003-07-30 2005-09-06 Black & Decker Inc. Impact wrench having an improved anvil to square driver transition
US20060151188A1 (en) * 2005-01-07 2006-07-13 Bodine Thomas J Impact wrench anvil and method of forming an impact wrench anvil
US20060266537A1 (en) * 2005-05-27 2006-11-30 Osamu Izumisawa Rotary impact tool having a ski-jump clutch mechanism
US20070084310A1 (en) * 2005-10-14 2007-04-19 Sp Air Kabushiki Kaisha Air ratchet tool with rotatable head
US20070141967A1 (en) * 2005-10-14 2007-06-21 Sp Air Kabushiki Kaisha Die Grinder with Rotatable Head
WO2009137684A1 (en) * 2008-05-07 2009-11-12 Milwaukee Electric Tool Corporation Drive assembly for a power tool
US20130112449A1 (en) * 2011-11-09 2013-05-09 Sing Hua Industrial Co., Ltd. Torsion increasing pneumatic tool percussion hammer
US20130233585A1 (en) * 2012-03-12 2013-09-12 Chun Yu Lin Pneumatic spanner structure
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US20160214238A1 (en) * 2015-01-23 2016-07-28 Storm Pneumtic Tool Co., Ltd. Pneumatic tool having an impact module with dual impact
TWI571363B (zh) * 2015-11-26 2017-02-21 動力工具之扳機裝置
US10688609B2 (en) 2017-04-14 2020-06-23 Tym Labs, L.L.C. Torque wrench having impact engager
US11259516B2 (en) * 2017-08-02 2022-03-01 BioHerbicides Australia Pty Ltd Method and apparatus for capsular delivery to plants
US11267110B2 (en) 2017-08-02 2022-03-08 Tym Labs L.L.C. Zero distance tool

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2128916A (en) * 1982-10-19 1984-05-10 Black & Decker Inc Impact mechanism for power driven wrench
JPH0947927A (ja) * 1995-08-07 1997-02-18 Toyota Motor Corp 回転アクチュエータ及びそれを使用したネジ締め機

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2285638A (en) * 1939-11-22 1942-06-09 Chicago Pneumatic Tool Co Impact clutch
US3380539A (en) * 1964-09-08 1968-04-30 Skil Corp Impact clutch

Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5199505A (en) * 1991-04-24 1993-04-06 Shinano Pneumatic Industries, Inc. Rotary impact tool
US5435398A (en) * 1994-09-01 1995-07-25 Chiu-Yu Wang Cheng Electrical wrench
EP0808694A1 (de) 1996-05-21 1997-11-26 Yotaro Taga Schalldämpfereinrichtung zur Verwendung in einem Schlagschrauber
US5740892A (en) * 1996-08-26 1998-04-21 Huang; Chen Shu-Hsia Power wrench torque transmission mechanism
US5784934A (en) * 1997-01-30 1998-07-28 Shinano Pneumatic Industries, Inc. Ratchet wrench with pivotable head
US5887666A (en) * 1997-08-04 1999-03-30 Chen; Kenneth Impact wrench structure
USD434298S (en) * 1999-12-06 2000-11-28 S.P. Air Kabusiki Kaisha Impact wrench
US6443239B1 (en) 2000-02-29 2002-09-03 S.P. Air Kabusiki Kaisha Pneumatic rotary tool
US6311583B1 (en) 2000-04-13 2001-11-06 S. P. Air Kabusiki Kaisha Ratchet wrench with pivotable head
US6491111B1 (en) 2000-07-17 2002-12-10 Ingersoll-Rand Company Rotary impact tool having a twin hammer mechanism
US20040159451A1 (en) * 2003-02-14 2004-08-19 Koji Taga Air intake and exhaust device for a pistol type air impact wrench
US20050022638A1 (en) * 2003-07-30 2005-02-03 Rodney Milbourne Impact wrench having an improved anvil to square driver transition
US6938526B2 (en) 2003-07-30 2005-09-06 Black & Decker Inc. Impact wrench having an improved anvil to square driver transition
US7036406B2 (en) 2003-07-30 2006-05-02 Black & Decker Inc. Impact wrench having an improved anvil to square driver transition
US7249638B2 (en) 2005-01-07 2007-07-31 Black & Decker Inc. Impact wrench anvil and method of forming an impact wrench anvil
US20060151188A1 (en) * 2005-01-07 2006-07-13 Bodine Thomas J Impact wrench anvil and method of forming an impact wrench anvil
US20070266545A1 (en) * 2005-01-07 2007-11-22 Bodine Thomas J Impact wrench anvil and method of forming an impact wrench anvil
US20060266537A1 (en) * 2005-05-27 2006-11-30 Osamu Izumisawa Rotary impact tool having a ski-jump clutch mechanism
US8480453B2 (en) 2005-10-14 2013-07-09 Sp Air Kabushiki Kaisha Die grinder with rotatable head
US20070084310A1 (en) * 2005-10-14 2007-04-19 Sp Air Kabushiki Kaisha Air ratchet tool with rotatable head
US20070141967A1 (en) * 2005-10-14 2007-06-21 Sp Air Kabushiki Kaisha Die Grinder with Rotatable Head
WO2009137684A1 (en) * 2008-05-07 2009-11-12 Milwaukee Electric Tool Corporation Drive assembly for a power tool
CN102083593B (zh) * 2008-05-07 2014-07-23 密尔沃基电动工具公司 用于电动工具的驱动组件
GB2471626B (en) * 2008-05-07 2013-02-13 Milwaukee Electric Tool Corp Drive assembly for a power tool
US20110048751A1 (en) * 2008-05-07 2011-03-03 Elger William A Drive assembly for a power tool
GB2471626A (en) * 2008-05-07 2011-01-05 Milwaukee Electric Tool Corp Drive assembly for a power tool
US8505648B2 (en) 2008-05-07 2013-08-13 Milwaukee Electric Tool Corporation Drive assembly for a power tool
US9289886B2 (en) 2010-11-04 2016-03-22 Milwaukee Electric Tool Corporation Impact tool with adjustable clutch
US20130112449A1 (en) * 2011-11-09 2013-05-09 Sing Hua Industrial Co., Ltd. Torsion increasing pneumatic tool percussion hammer
US20130233585A1 (en) * 2012-03-12 2013-09-12 Chun Yu Lin Pneumatic spanner structure
US9193056B2 (en) * 2012-03-12 2015-11-24 Chun Yu Lin Pneumatic spanner structure
US20160214238A1 (en) * 2015-01-23 2016-07-28 Storm Pneumtic Tool Co., Ltd. Pneumatic tool having an impact module with dual impact
TWI571363B (zh) * 2015-11-26 2017-02-21 動力工具之扳機裝置
US10688609B2 (en) 2017-04-14 2020-06-23 Tym Labs, L.L.C. Torque wrench having impact engager
US11259516B2 (en) * 2017-08-02 2022-03-01 BioHerbicides Australia Pty Ltd Method and apparatus for capsular delivery to plants
US11267110B2 (en) 2017-08-02 2022-03-08 Tym Labs L.L.C. Zero distance tool

Also Published As

Publication number Publication date
DE1939262A1 (de) 1970-02-26
DE1939262C2 (de) 1982-12-23
FR2016255A1 (de) 1970-05-08
GB1231732A (de) 1971-05-12
SE374880B (de) 1975-03-24
BE737849A (de) 1970-02-02

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