The present disclosure relates to rotary tools that include an impact mechanism, such as impact drivers, impact wrenches, and the like.
Rotary impact tools are used to tighten or loosen fasteners. Rotary impact tools often include a drive motor with a motor shaft, a hammer driven by the motor shaft, and an anvil that is impacted by the hammer so that the anvil is rotated and thereby drives a fastener. Most impact mechanisms are configured to transmit high-torque rotational force to the anvil (and subsequently a fastener) while requiring relatively low-torque reaction forces be absorbed by the motor and/or an operator holding the rotary impact tool. More specifically, by using the motor to repeatedly accelerate the hammer while it is out of contact with the anvil and then bringing the hammer only briefly into contact with the anvil, the anvil is imparted with a high-torque rotational force from the impacts of the hammer, while the motor's stator is exposed only to low-torque reaction forces corresponding generally to the free acceleration of the hammer.
According to one aspect, a rotary impact tool may comprise a motor including a rotor and an input shaft coupled to the rotor for rotation therewith about an input axis, an anvil configured to be rotated about an output axis, the anvil including an output shaft, a first lug extending outward in a radial direction from the output shaft and extending a first distance around the output shaft in a circumferential direction, and a second lug extending outward in the radial direction from the output shaft and extending a second distance different from the first distance around the output shaft in the circumferential direction, and a first hammer driven by the input shaft and configured to impact the anvil to cause the anvil to rotate about the output axis.
In some embodiments, the input shaft axis and the output shaft axis may be collinear. In other embodiments, the input shaft axis and the output shaft axis may be non-parallel.
In some embodiments, the output shaft may have a proximal end and a distal end spaced apart from the proximal end, the distal end being adapted to be coupled to a fastener driver, and the first lug may be spaced further from the proximal end than the second lug. The second lug may extend further around the output shaft in the circumferential direction than the first lug. The first lug may be spaced apart from the second lug around the output shaft in the circumferential direction. The first lug may be arranged circumferentially opposite the second lug around the output shaft. The first lug and the second lug may extend substantially the same distance along the output axis.
In some embodiments, the rotary impact tool may further comprise a second hammer driven by the input shaft and configured to impact the anvil to cause the anvil to rotate about the output axis. The first hammer may extend around the output shaft and the first lug, and the second hammer may extend around the output shaft and the second lug. The rotary impact tool may further comprise a carrier coupled to the input shaft for rotation therewith, wherein the first hammer is coupled to the carrier for rotation relative to the carrier about a first hammer axis spaced apart from the output axis and the second hammer is coupled to the carrier for rotation relative to the carrier about a second hammer axis spaced apart from the output axis and the first hammer axis.
According to another aspect, a drive train may comprise an input shaft rotatable about an input axis, an anvil configured to rotate about an output axis, the anvil including an output shaft, a first lug extending a first distance around the output shaft through a first angle, and a second lug extending a second distance around the output shaft through a second angle different from the first angle, and a first hammer extending around the anvil and configured to be driven by the input shaft to impact at least one of the first lug and the second lug to drive rotation of the anvil about the output axis.
In some embodiments, the second lug may be closer to the input shaft than the first lug, and the second angle may be greater than the first angle. The first lug may be arranged circumferentially opposite the second lug around the output shaft. The first lug and the second lug may have substantially the same axial length along the output axis.
In some embodiments, the drive train may further comprise a second hammer, wherein the first hammer extends around the output shaft and the first lug and the second hammer extends around the output shaft and the second lug. The drive train may further comprise a carrier coupled to the input shaft for rotation therewith about the input axis, wherein the first hammer is coupled to the carrier for rotation therewith about the input axis and the second hammer is coupled to the carrier for rotation therewith about the input axis. The first hammer may be coupled to the carrier for rotation relative to the carrier about a first hammer axis spaced apart from the input axis, and the second hammer may be coupled to the carrier for rotation relative to the carrier about a second hammer axis spaced apart from the input axis and the first hammer axis.
According to yet another aspect, a drive train may comprise an input shaft rotatable about an input axis, an anvil configured to rotate about an output axis, the anvil including an output shaft, a first lug extending outward in a radial direction from the output shaft, and a second lug extending outward in the radial direction from the output shaft, and an impactor including a first hammer configured to impact the first lug to drive rotation of the anvil about the output axis and a second hammer configured to impact the second lug to drive rotation of the anvil about the output axis. The first hammer may include an outer ring and a pair of impact jaws extending inwardly in the radial direction from the outer ring, the second hammer may include an outer ring and a pair of impact jaws extending inwardly in the radial direction from the outer ring, the pair of impact jaws of the first hammer may be spaced a first distance apart around the outer ring of the first hammer, and the pair of impact jaws of the second hammer may be spaced a second distance apart around the outer ring of the second hammer different from the first distance.
In some embodiments, the output shaft may have a proximal end and a distal end adapted to be coupled to a fastener driver, the first lug may be spaced further from the proximal end than the second lug, and the first distance may be smaller than the second distance. The impactor may include a carrier coupled to the input shaft for rotation therewith about the input axis, the first hammer may be coupled to the carrier for rotation relative thereto about a first hammer axis, and the second hammer may be coupled to the carrier for rotation relative thereto about a second hammer axis.
The concepts described in the present disclosure are illustrated by way of example and not by way of limitation in the accompanying drawings. For simplicity and clarity of illustration, elements illustrated in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference labels have been repeated among the drawings to indicate corresponding or analogous elements.
While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.
One illustrative embodiment of an impact tool 10 that may be used to drive a fastener is shown in
Turning to
The motor 24 includes a rotor 38 and a motor shaft 40, as shown in
Referring now to
In the illustrative embodiment, each lug 51, 52 of the anvil 26 extends outward in a radial direction from the output shaft 50, as shown in
The impactor 28 illustratively includes a carrier 30, an aft hammer 31, and a forward hammer 32, as shown in
In the illustrative embodiment, each hammer 31, 32 is hollow and extends around the anvil 26 as shown in
The aft hammer 31 is formed to include a first notch 71 and a second notch 72 each extending inward in the radial direction into the outer ring 64 as shown in
The forward hammer 32 is similar to the aft hammer 31 and is formed to include a first notch 73 and a second notch 74 each extending inward in the radial direction into the outer ring 67 as shown in
Turning specifically to
Sizing of the aft lug 51 to extend further around the output shaft 50 than the forward lug 52 promotes even loading of the lugs 51, 52 when torque is applied to the anvil 26 during operation of the impact tool 10. In other words, this unequal sizing of the aft lug 51 and the forward lug 52 may reduce or eliminate uneven loading that would otherwise occur due to torsional windup of the anvil 26 during high torque operation of an impact tool 10. By evenly loading the lugs 51, 52 of the anvil 26, the life of the anvil 26 may be extended, with a need for additional and/or strengthened materials.
Turning now to
Unlike anvil 26, the anvil 126 includes an aft lug 151 and a forward lug 152 that both extend the same distance around an output shaft 150 included in the anvil 126, as best seen in
In the illustrative embodiment of
While certain illustrative embodiments have been described in detail in the figures and the foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, systems, and methods described herein. It will be noted that alternative embodiments of the apparatus, systems, and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the apparatus, systems, and methods that incorporate one or more of the features of the present disclosure.