Rotary impact tool and clutch therefor

Claim 2

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and mounted for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected in said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the axis of rotation of said carrier member, said hammer member for clockwise impact operation having a clockwise impact delivering jaw on its inside surface located between 0* and 90* clockwise from its pivot connection to the carrier member, said impact jaw being movable into and out of the path of said impact receiving anvil jaw to deliver an impact blow thereto, cam means for effecting the angular pivot movement of said impact delivering jaw into the path of said anvil jaw in a clockwise direction relative to said carrier member, centrifugal force created by the proportions, mass and mass center location of said hammer member holding said impact delivering jaw in the path of said anvil jaw until the delivery of said impact blow thereto, and automatic means for effecting the angular pivot movement of said impact jaw out of the path of said anvil jaw in a counter clockwise direction in relation to said carrier member after the delivery of said impact blow.

Claim 3

A rotary impact tool as set forth in claim 1 wherein said hammer member extends around said output shaft for at least 170*.

Claim 4

A rotary impact tool as set forth in claim 2 wherein said hammer member completely surrounds said output shaft.

Claim 5

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially arouNd said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected in said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the axis of rotation of said carrier member, said hammer member having a clockwise impact jaw on its inner surface located between 0* and 90* clockwise from its pivot axis to the carrier member so that when the hammer member is pivoted in a clockwise direction the clockwise impact jaw moves inwardly toward said impact receiving anvil jaw, cam means to produce said pivot motion, and centrifugal detent means to hold said impact jaw in said pivoted position to mate with the anvil jaw and produce a disengaging pivot torque on the hammer member tending to pivot it out of engagement with the anvil jaw, the inertia of said rotating hammer member acting to prevent said disengaging motion during an impact blow.

Claim 6

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially arouNd said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected in said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the axis of rotation of said carrier member, said hammer member having a clockwise impact jaw on its inner surface located between 0* and 90* clockwise from its pivot axis to the carrier member so that when the hammer member is pivoted in a clockwise direction the clockwise impact jaw moves inwardly toward said impact receiving anvil jaw, cam means to produce said pivot motion, and centrifugal detent means to hold said impact jaw in said pivoted position to mate with the anvil jaw and produce a disengaging pivot torque on the hammer member tending to pivot it out of engagement with the anvil jaw, the inertia of said rotating hammer member acting to prevent said disengaging motion during an impact blow.

Claim 7

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation and including an impact receiving anvil jaw having an impact receiving surface means generally radially disposed on its periphery, a carrier member mounted for coaxial rotation about said output shaft and driven by said motor, a hollow hammer member surrounding said anvil jaw and having an inner surface with impact delivering surface means pivotally mounted in said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis parallel to but offset from the axis of rotation of said carrier member, said impact delivering surface means located between 0* and 90* clockwise from said pivot connection to the carrier member, said impact delivering surface means and said impact receiving surface means so arranged that upon clockwise rotation of said carrier member said impact delivering surface means contacts said impact receiving surface means to deliver a clockwise impact blow and to produce a counterclockwise pivot torque on said hammer member to tend to pivot said impact delivering surface means out of engagement with said impact receiving surface means.

Claim 8

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation and including an impact receiving anvil jaw having an impact receiving surface means generally radially disposed on its periphery, a carrier member mounted for coaxial rotation about said output shaft and driven by said motor, a hollow hammer member surrounding said anvil jaw and having an inner surface with impact delivering surface means pivotally mounted in said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis parallel to but offset from the axis of rotation of said carrier member, said impact delivering surface means located between 0* and 90* clockwise from said pivot connection to the carrier member, said impact delivering surface means and said impact receiving surface means so arranged that upon clockwise rotation of said carrier member said impact delivering surface means contacts said impact receiving surface means to deliver a clockwise impact blow and to produce a counterclockwise pivot torque on said hammer member to tend to pivot said impact delivering surface means out of engagement with said impact receiving surface means.

Claim 9

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface located within 90* of its connection to said carrier member and so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that same direction to move said impact delivering jaw into the annular path of rotation of said anvil jaw, cam means to effect said pivot motion, centrifugal force created by the proportions, the mass and the mass center location of said hammer member holding said impact delivering jaw in said pivoted position to deliver an impact blow in that direction to said anvil jaw.

Claim 10

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface located within 90* of its connection to said carrier member and so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that same direction to move said impact delivering jaw into the annular path of rotation of said anvil jaw, cam means to effect said pivot motion, centrifugal force created by the proportions, the mass and the mass center location of said hammer member holding said impact delivering jaw in said pivoted position to deliver an impact blow in that direction to said anvil jaw.

Claim 11

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in rEspect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface, so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that said direction to move said impact jaw into the annular path of rotation of said anvil jaw, cam means to effect said pivot motion, centrifugal force created by the proportions, the mass and the mass center location of said hammer member holding said hammer jaw in said pivoted position until it contacts said anvil jaw directly, urging same in said direction and creating an opposite pivot torque on said hammer member, the proportions, mass and mass center location of said hammer member also causing inertia forces during decelleration due to an impact blow sufficient to counter the disengaging pivot motion until the momentum of the carrier and hammer members in said one direction is dissipated.

Claim 12

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in rEspect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface, so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that said direction to move said impact jaw into the annular path of rotation of said anvil jaw, cam means to effect said pivot motion, centrifugal force created by the proportions, the mass and the mass center location of said hammer member holding said hammer jaw in said pivoted position until it contacts said anvil jaw directly, urging same in said direction and creating an opposite pivot torque on said hammer member, the proportions, mass and mass center location of said hammer member also causing inertia forces during decelleration due to an impact blow sufficient to counter the disengaging pivot motion until the momentum of the carrier and hammer members in said one direction is dissipated.

Claim 13

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member extending from its pivot connection with the carrier member to substantially beyond the said axis of rotation on both sides of the anvil so as to generally surround the anvil, and including an impact delivering jaw on its inside surface so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that said direction to move said impact jaw into the annular path of rotation of said anvil jaw to contact said anvil jaw directly, urging said anvil jaw in said direction and creating an opposite pivot torque on said hammer member which becomes effective only after the momentum of said rotating members in said direction has been dissipated.

Claim 14

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member extending from its pivot connection with the carrier member to substantially beyond the said axis of rotation on both sides of the anvil so as to generally surround the anvil, and including an impact delivering jaw on its inside surface so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that said direction to move said impact jaw into the annular path of rotation of said anvil jaw to contact said anvil jaw directly, urging said anvil jaw in said direction and creating an opposite pivot torque on said hammer member which becomes effective only after the momentum of said rotating members in said direction has been dissipated.

Claim 15

The impact tool of claim 8, wherein said hammer member is proportioned, has a mass and a mass center location which cause inertia forces acting on said hammer member while it contacts said anvil jaw during the dissipation of said momentum to overcome said opposite pivot torque.

Claim 16

The impact tool of claim 9, wherein said hammer member proportions, mass and mass center location also cause a centrifugal force to hold said impact jaw in the path of said anvil jaw prior to said contact between said jaws.

Claim 17

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface capable of being pivoted into and out of the path of the anvil jaw, cam means to pivot said impact Delivering jaw into said path, centrifugal force holding said impact delivering jaw in said path until impact with the anvil jaw, and cam means to pivot said impact delivering jaw out of said path including impact surfaces of said hammer and anvil jaw being shaped so that during the impact of said hammer member with said anvil jaw a camming force is created acting on the hammer member tending to cause the hammer jaw to pivot outwardly to disengage from said anvil jaw, and said hammer member being so positioned, proportioned and having a mass and a mass center location which will cause the creation of inertia forces acting on said hammer member during the interval of said impact until the momentum of said hammer and carrier members is dissipated, thereby overcoming said camming force and preventing said hammer jaw from pivoting outwardly during the interval of impact, said mass center being closer to the carrier axis than to the hammer pivot axis.

Claim 18

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface capable of being pivoted into and out of the path of the anvil jaw, cam means to pivot said impact Delivering jaw into said path, centrifugal force holding said impact delivering jaw in said path until impact with the anvil jaw, and cam means to pivot said impact delivering jaw out of said path including impact surfaces of said hammer and anvil jaw being shaped so that during the impact of said hammer member with said anvil jaw a camming force is created acting on the hammer member tending to cause the hammer jaw to pivot outwardly to disengage from said anvil jaw, and said hammer member being so positioned, proportioned and having a mass and a mass center location which will cause the creation of inertia forces acting on said hammer member during the interval of said impact until the momentum of said hammer and carrier members is dissipated, thereby overcoming said camming force and preventing said hammer jaw from pivoting outwardly during the interval of impact, said mass center being closer to the carrier axis than to the hammer pivot axis.

Claim 19

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member in a given direction, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface, said hammer member being proportioned, and having a mass and a mass center location which will cause the creation of a centrifugal torque acting on said hammer member prior to the impact of said jaws to hold said hammer jaw pivoted inwardly in position to strike said anvil jaw prior to said impact and will cause the creation of inertia forces acting on said hammer during rebound of the hammer following said impact, after the momentum of said rotating members in said given direction has been dissipated, that will cause said hammer jaw to pivot outwardly to a position where it can rotate past said anvil jaw during further rotation in said given direction.

Claim 20

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member in a given direction, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface, said hammer member being proportioned, and having a mass and a mass center location which will cause the creation of a centrifugal torque acting on said hammer member prior to the impact of said jaws to hold said hammer jaw pivoted inwardly in position to strike said anvil jaw prior to said impact and will cause the creation of inertia forces acting on said hammer during rebound of the hammer following said impact, after the momentum of said rotating members in said given direction has been dissipated, that will cause said hammer jaw to pivot outwardly to a position where it can rotate past said anvil jaw during further rotation in said given direction.

Claim 21

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface, cam means to move said impact delivering jaw inwardly into the path of rotation of said anvil jaw, said hammer impact jaw being located relative to the hammer pivot axis so that the impact between said hammer impact delivering jaw and said anvil jaw will create compressive stresses in said hammer member between its impact delivering jaw and said pivot axis, said hammer member being proportioned and having a mass and a mass center location which will cause the creation of a centrifugal torque acting on said hammer member prior to the impact between said impact jaws to hold said hammer jaw pivoted inwardly in position to strike said impact.

Claim 22

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotating said carrier member, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface, cam means to move said impact delivering jaw inwardly into the path of rotation of said anvil jaw, said hammer impact jaw being located relative to the hammer pivot axis so that the impact between said hammer impact delivering jaw and said anvil jaw will create compressive stresses in said hammer member between its impact delivering jaw and said pivot axis, said hammer member being proportioned and having a mass and a mass center location which will cause the creation of a centrifugal torque acting on said hammer member prior to the impact between said impact jaws to hold said hammer jaw pivoted inwardly in position to strike said impact.

Claim 23

The wrench mechanism of claim 13 wherein said hammer member extends around said anvil over an angle of at least 170*.

Claim 24

The wrench mechanism of claim 13 wherein said hammer member extends completely around said anvil.

Claim 25

The wrench mechanism of claim 13 wherein the mass center of said hammer member is closer to the axis of said carrier member than to said pivot axis of said hammer member.

Claim 26

The wrench mechanism of claim 13 wherein the impact surfaces of said hammer jaw and anvil jaw are shaped so that during the impact of said hammer jaw with said anvil jaw a camming force is created acting on the hammer member tending to cause its jaw to pivot outwardly to disengage said jaw during said impact, and said hammer member being also proportioned and having a mass and a mass center location which will cause the creation of inertia forces acting on said hammer member during the interval of said impact that will overcome said camming force and will prevent said hammer member from pivoting outwardly during the interval of impact.

Claim 27

The wrench mechanism of claim 13 wherein said hammer is positioned, proportioned and having a mass and a mass center location that will cause the creation of inertia forces acting on said hammer during rebound of the hammer following the impact of said impact surfaces that will cause said hammer to tilt outward to a position where it can rotate past said anvil jaw during further forward rotation.

Claim 28

The wrench mechanism of claim 13 wherein a pair of said anvil jaws are mounted on said output shaft and angularly and longitudinally spaced from each other; and a pair of said hammer members is pivoted in said carrier member in an angular and longitudinal spaced relationship and arranged to impact simultaneously with said anvil jaws.

Claim 29

The wrench mechanism of claim 19 wherein said anvil jaws are angularly spaced 180* from each other.

Claim 30

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotation said carrier member as said motor is rotating, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface located within 90* of its pivot connection on said carrier member and so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that same direction to move said impact delivering jaw into the annular path of rotation of said anvil jaw to deliver an impact blow in that direction, and cam means on said hammer member located and adapted to engage said anvil jaw to pivot said impact delivering jaw into the path of said anvil jaw at least 90* prior to the delivery of said impact blow, said hammer and anvil jaw allowing said impact delivering jaw to remain in the path of said anvil jaw while said hammer member rotates through said 90* angle ending at the delivery of said impact blow.

Claim 31

A rotary impact tool comprising, in combination, a housing, a motor mounted in said housing, an output shaft mounted on said housing for rotation about an axis and including an impact receiving anvil jaw generally radially disposed on its periphery, a carrier member coaxially around said output shaft and journaled for rotation in respect to said output shaft, driving connection means between said motor and said carrier member for rotation said carrier member as said motor is rotating, a hammer member pivotally connected to said carrier member for rotation therewith and for angular pivotal motion relative thereto about an axis offset from but parallel to the said axis of rotation of said carrier member, said hammer member including an impact delivering jaw on its inside surface located within 90* of its pivot connection on said carrier member and so positioned that for operation of the tool in one direction said hammer member pivots relative to the carrier member in that same direction to move said impact delivering jaw into the annular path of rotation of said anvil jaw to deliver an impact blow in that direction, and cam means on said hammer member located and adapted to engage said anvil jaw to pivot said impact delivering jaw into the path of said anvil jaw at least 90* prior to the delivery of said impact blow, said hammer and anvil jaw allowing said impact delivering jaw to remain in the path of said anvil jaw while said hammer member rotates through said 90* angle ending at the delivery of said impact blow.

Claim 32

The rotary impact tool of claim 21 wherein said hammer member extends at least 170* around said output shaft.

Claim 33

The rotary impact tool of claim 21 wherein said cam means on said hammer member is disengaged from said anvil jaw for at least the last 90* prior to striking the impact blow.