Right angle impact tool

An angle impact tool includes a handle assembly extending along a first axis, a prime mover in the handle, an output shaft rotatable about the first axis, and a work attachment connected to the handle assembly. An output drive is supported in the work attachment for rotation about an output axis perpendicular to the first axis. A gear assembly including a spur gear is positioned within the work attachment to transfer torque from the prime mover about the first axis to the output drive about the output axis. An impact mechanism is positioned within the work attachment and includes a hammer and an anvil. The hammer rotates under the influence of the prime mover and is operable to periodically deliver an impact load to the anvil. The output drive rotates about the output axis under the influence of the impact load being transmitted to the output drive by the anvil.

FIELD OF THE INVENTION

The present invention relates to gear arrangements for angle impact tools.

SUMMARY

In one embodiment, the invention provides an angle impact tool including a handle assembly extending along a first axis and graspable by a user. A prime mover is positioned in the handle and includes an output shaft rotatable about the first axis. A work attachment is connected to the handle assembly. An output drive is supported in the work attachment for rotation about an output axis perpendicular to the first axis. A gear assembly is positioned within the work attachment. The gear assembly includes at least one spur gear and is operable to transfer torque from the prime mover about the first axis to the output drive about the output axis. An impact mechanism is positioned within the work attachment. The impact mechanism includes a hammer and an anvil. The hammer rotates under the influence of the prime mover and is operable to periodically deliver an impact load to the anvil. The output drive rotates about the output axis under the influence of the impact load being transmitted to the output drive by the anvil.

In another embodiment, the invention provides an angle impact tool including a handle assembly graspable by a user, and a prime mover at least partially contained within the handle assembly. The prime mover has a rotor rotatable about a first axis. An output drive is functionally coupled to the prime mover and selectively rotated in response to rotation of the rotor. The output drive defines an output axis about which the output drive rotates. The output axis is substantially perpendicular to the first axis. At least one bevel gear is functionally positioned between the rotor and the output drive. The at least one bevel gear is rotatable in response to rotation of the rotor. At least one spur gear is functionally positioned between the rotor and the output drive. The at least one spur gear is rotatable in response to rotation of the rotor. An impact mechanism is functionally positioned between the prime mover and the output drive. The impact mechanism selectively drives the output drive with impact forces in response to rotation of the rotor.

In yet another embodiment, the invention provides an angle impact tool including a handle assembly extending generally along a first axis and graspable by a user, a prime mover having an output shaft rotatable about the first axis, and an output drive functionally coupled to the prime mover and selectively rotated in response to rotation of the output shaft. The output drive defines an output axis about which the output drive rotates. The output axis is substantially perpendicular to the first axis. A first spur gear is functionally positioned between the prime mover and the impact mechanism. The first spur gear is rotatable in response to rotation of the output shaft. A second spur gear meshes with the first spur gear for rotation in response to rotation of the first spur gear. A third spur gear meshes with the second spur gear for rotation in response to rotation of the first and second spur gears. A first bevel gear is connected to the output shaft for rotation with the output shaft about the first axis. A second bevel gear is functionally positioned between the first bevel gear and the first spur gear, such that rotation of the first bevel gear about the first axis causes rotation of the second bevel gear to rotate about a second axis and the first spur gear to rotate about a third axis. The second axis and the third axis are substantially perpendicular to the first axis. An impact mechanism is functionally positioned between the prime mover and the output drive. The impact mechanism selectively drives the output drive in response to rotation of the output shaft. The impact mechanism includes a hammer functionally coupled to the output shaft for rotation with the output shaft, and an anvil functionally coupled to the output drive. The hammer is operable to impact the anvil to drive the output drive with impact forces in response to rotation of the output shaft.

DETAILED DESCRIPTION

FIGS. 1 and 2illustrate an angle impact tool10that includes a handle or motor assembly12and a work attachment14. The illustrated motor assembly12includes a motor16, a motor housing18, a motor bracket20, a first grip portion22, a second grip portion24, a trigger lever26, and a lock ring28. The lock ring28and a plurality of fasteners30retains the first and second grip portions22and24together. The motor housing18is coupled to the first and second grip portions22and24by a plurality of fasteners32and a U-shaped part34. A switch36is included in the motor assembly12between the first and second grip portions22and24. The switch36is coupled (mechanically and/or electrically) to the trigger lever26, such that actuation of the trigger lever26causes actuation of the switch36, and therefore, operation of the motor16.

The motor bracket20is coupled to the motor16by a plurality of fasteners38. The motor16includes an output shaft, such as the illustrated rotor40, that is rotatable about a longitudinal handle axis42. The illustrated motor16is an electric motor, but any suitable prime mover, such as the pneumatic motor disclosed in U.S. Published Application No. 2009/0272554, which is herein incorporated by reference, can be utilized. Although not specifically illustrated, a battery and a directional reverse switch are provided on the angle impact tool10.

The illustrated work attachment14includes an angle housing46and an angle housing plate48. A plurality of fasteners50couple the angle housing plate48to the angle housing46. The motor housing18is coupled to the angle housing46with a plurality of fasteners52. The motor bracket20is coupled to the angle housing46by a plurality of fasteners54.

The illustrated work attachment14houses a gear assembly58and an impact mechanism60. The gear assembly58includes a first bevel gear62coupled to the rotor40for rotation with the rotor40about the longitudinal handle axis42. A first bearing64is positioned between the first bevel gear62and the motor bracket20. The illustrated gear assembly58includes a second bevel gear66that meshingly engages the first bevel gear62. The second bevel gear66is coupled to a shaft68for rotation with the shaft68. The shaft68is supported in the work attachment14by bearings70aand70b. The shaft68includes a splined portion72near bearing70b. The shaft68rotates about an axis74(FIG. 4). The splined portion72functions as a spur gear and in some embodiments, can be replaced with a spur gear.

The splined portion72engages a gear, such as a first spur gear76, such that rotation of the splined portion72causes rotation of the first spur gear76about an axis78(FIG. 4). The first spur gear76is coupled to a second shaft80for rotation with the second shaft80(FIG. 4) about the axis78. The second shaft80is supported for rotation with respect to the work attachment14by bearings82a,82b.

The first spur gear76meshes with a second spur gear84to cause rotation of the second spur gear84about an axis86(FIG. 4). The second spur gear84is coupled to a square drive88through the impact mechanism60for selectively rotating the square drive88. The second spur gear84and the square drive88are supported for rotation within the angle housing46by bearings90a,90b,90c(FIG. 4). The axes74,78and86are all substantially parallel to each other and are thus each substantially perpendicular to axis42.

The square drive88is connectable to a socket or other fastener-driving output element. In some constructions, the work attachment14can be substantially any tool adapted to be driven by a rotating output shaft of the motor16, including but not limited to an impact wrench, gear reducer, and the like.

With reference toFIGS. 2-4, the impact mechanism60can be a standard impact mechanism, such as a Potts mechanism or a Maurer mechanism. The illustrated impact mechanism60includes a cam shaft94coupled to the second spur gear84for rotation with the second spur gear84about the second axis86. The illustrated cam shaft94includes opposite cam grooves96a,96bthat define pathways for respective balls98a,98b. The illustrated impact mechanism60further includes a hammer100that includes opposite cam grooves102a,102bthat are substantially mirror-images of cam grooves96a,96b. The balls98a,98bare retained between the respective cam grooves96a,96b,102a,102b. The hammer100also includes first and second opposite jaws104a,104b.

The first bevel gear62actuates the gear assembly58and the impact mechanism60to functionally drive an output, such as the square drive88, as shown in the illustrated embodiment. The square drive88is rotated about the axis86which is non-parallel to the axis42. In the illustrated embodiment, the axis86is perpendicular to the axis42. In other embodiments (not shown), the axis86is at an acute or obtuse non-parallel angle to the axis42.

A biasing member, such as an axial compression spring106is positioned between the second spur gear84and the hammer100to bias the hammer100away from the second spur gear84. In the illustrated embodiment, the spring106rotates with the second spur gear84and the bearing90cpermits the hammer100to rotate with respect to the spring106. Other configurations are possible, and the illustrated configuration is given by way of example only.

The illustrated square drive88is formed as a single unitary, monolithic piece with first and second jaws108a,108bto create an anvil110. The anvil110is supported for rotation within the angle housing46by the bearing90a. The jaws104a,104bimpact respective jaws108a,108bto functionally drive the square drive88in response to rotation of the second spur gear84. The term “functionally drive” is herein defined as a relationship in which the jaws104a,104brotate to impact the respective jaws108a,108band thereby cause intermittent rotation of the square drive88, in response to the impact of jaws104a,104bon the respective jaws108a,108b. The jaws104a,104bintermittently impact the jaws108a,108b, and therefore the jaws104a,104bfunctionally drive rotation of the square drive88. Further, any element that directly or indirectly drives rotation of the hammer to impact the anvil may be said to “functionally drive” any element that is rotated by the anvil as a result of such impact.

The impact cycle is repeated twice every rotation and is illustrated inFIGS. 5A-5Jin which the jaws104a,104bimpact the jaws108a,108b. The spring106permits the hammer100to rebound after impact and balls98a,98bguide the hammer100to ride up around the cam shaft94, such that jaws104a,104bare spaced axially from jaws108a,108b. The jaws104a,104bare permitted to rotate past the jaws108a,108bafter the rebound.FIGS. 5A-5Jillustrate an impact cycle of the impact tool ofFIGS. 1-4. Two such impact cycles occur per rotation of the hammer100.

A head height dimension114of the work attachment14is illustrated inFIG. 4. The head height dimension114is the axial distance from the top of the angle housing plate48to the bottom of the angle housing46. The head height dimension114is reduced so that the work attachment14can fit into small spaces. The motor housing18defines a motor housing height dimension118, as shown inFIG. 4. The head height dimension114is smaller than or substantially equal to the motor housing height dimension118. Such a configuration permits insertion of the tool10into smaller spaces than has previously been achievable without compromising torque. In one embodiment, the head height dimension114is less than two inches, and the angle impact tool10has a maximum torque of about 180 foot-pounds and a rate of rotation of about 7,100 rotations-per-minute.

FIGS. 6 and 7illustrate an alternate embodiment of an angle head work attachment214for an angle impact tool. The angle head work attachment214is coupled to a handle and motor216having a rotor240. The motor216is supported by a motor housing218. The illustrated motor216is an electric motor, but any suitable prime mover, such as the pneumatic motor disclosed in U.S. Published Application No. 2009/0272554, which is herein incorporated by reference, can be utilized. Although not specifically illustrated, a battery and a directional reverse switch are provided on the angle impact tool.

The angle head work attachment214includes an angle housing246and an angle housing plate248that support a gear assembly258and an impact mechanism260. The rotor240rotates about a longitudinal handle axis242. A first bevel gear262is coupled to the rotor240for rotation with the rotor240about the longitudinal handle axis242. A first bearing264is positioned between the first bevel gear262and the motor housing218. The illustrated gear assembly258includes a second bevel gear266that meshingly engages the first bevel gear262. The second bevel gear266is coupled to a shaft268for rotation with the shaft268. The shaft268is supported in the work attachment214by bearings270aand270b. The shaft268includes a splined portion272near bearing270b. The shaft268rotates about an axis274. The splined portion272functions as a spur gear and in some embodiments, can be replaced with a spur gear.

The splined portion272engages a gear, such as a first spur gear276, such that rotation of the splined portion272causes rotation of the first spur gear276about an axis278. The first spur gear276is coupled to a second shaft280for rotation with the second shaft280about the axis278. The second shaft280is supported for rotation with respect to the work attachment214by bearings282b.

The first spur gear276meshes with a second spur gear284to cause rotation of the second spur gear284about an axis286. The second spur gear284is coupled to a square drive288through the impact mechanism260for selectively rotating the square drive288. The second spur gear284and the square drive288are supported for rotation with respect to the work attachment214by bushing290aand bearings290b,290c. The axes274,278and286are all substantially parallel to each other and are thus each substantially perpendicular to axis242.

The square drive288is connectable to a socket or other fastener-driving output element. In some constructions, the work attachment214can be substantially any tool adapted to be driven by a rotating output shaft of the motor216, including but not limited to an impact wrench, gear reducer, and the like.

The impact mechanism260can be a standard impact mechanism, such as a Potts mechanism or a Maurer mechanism. The illustrated impact mechanism260includes a cam shaft294coupled to the second spur gear284for rotation with the second spur gear284about the second axis286. The illustrated cam shaft294includes opposite cam grooves296a,296bthat define pathways for respective balls298a,298b. The illustrated impact mechanism260further includes a hammer300that includes opposite cam grooves302a,302bthat are substantially mirror-images of cam grooves296a,296b. The balls298a,298bare retained between the respective cam grooves296a,296b,302a,302b. The hammer300also includes first and second opposite jaws304a,304b.

The first bevel gear262actuates the gear assembly258and the impact mechanism260to functionally drive an output, such as the square drive288, as shown in the illustrated embodiment. The square drive288is rotated about the axis286which is non-parallel to the axis242. In the illustrated embodiment, the axis286is perpendicular to the axis242. In other embodiments (not shown), the axis286is at an acute or obtuse non-parallel angle to the axis242.

A biasing member, such as an axial compression spring306is positioned between the second spur gear284and the hammer300to bias the hammer300away from the second spur gear284. In the illustrated embodiment, the spring306rotates with the hammer100and the bearing290cpermits the second spur gear284to rotate with respect to the spring106. Other configurations are possible, and the illustrated configuration is given by way of example only.

The illustrated square drive288is formed as a single unitary, monolithic piece with first and second jaws308a,308bto create an anvil310. The anvil310is supported for rotation within the work attachment214by the bushing290a. The jaws304a,304bimpact respective jaws308a,308bto functionally drive the square drive288in response to rotation of the second spur gear284. The impact cycle is repeated twice every rotation and is similar to the impact cycled illustrated inFIGS. 5A-5J. During the impact cycle, the jaws304a,304bimpact the jaws308a,308b. The spring306permits the hammer300to rebound after impact and balls298a,298bguide the hammer300to ride up around the cam shaft294, such that jaws304a,304bare spaced axially from jaws308a,308b. The jaws304a,304bare permitted to rotate past the jaws308a,308bafter the rebound.

A head height dimension314of the work attachment214is illustrated inFIG. 7. The head height dimension314is the axial distance from the top of the angle housing246to the bottom of the angle housing246. The head height dimension314is reduced so that the work attachment214can fit into small spaces. The motor housing218defines a motor housing height dimension318, as shown inFIG. 7. The head height dimension314is smaller than or substantially equal to the motor housing height dimension318. Such a configuration permits insertion of the tool and the work attachment214into smaller spaces than has previously been achievable without compromising torque.

Thus, the invention provides, among other things, an angle impact tool. Various features and advantages of the invention are set forth in the following claims.