Patent Application
20150196997
The present disclosure relates, generally, to impact tools and, more particularly, to impact tools having controlled pivot impact mechanisms.
An impact tool (e.g., an impact wrench) may be used to install and remove fasteners. An impact tool generally includes a motor coupled to an impact mechanism. The impact mechanism converts torque provided by the motor into a series of powerful rotary blows directed from one or more hammers to an anvil that is integrally formed with (or otherwise coupled to) an output shaft of the impact tool. In typical impact mechanisms, the timing of these rotary blows is mechanically dependent on the size and shape of the hammer(s) and anvil, the rotational speed of the hammer(s), and other mechanical characteristics of the impact mechanism.
According to one aspect, an impact tool may comprise a hammer configured to rotate about a first axis and to pivot about a second axis different from the first axis, the hammer including a cam groove formed in an outer surface of the hammer, an actuator coupled to the cam groove of the hammer and configured to pivot the hammer about the second axis between a disengaged position and an engaged position based on a position of the actuator along the cam groove, and an anvil configured to rotate about the first axis in response to being impacted by the hammer when the hammer is in the engaged position.
In some embodiments, the impact tool may further comprise a controller configured to sense a rotational speed of the hammer about the first axis and cause the actuator to pivot the hammer from the disengaged position, in which the hammer rotates about the first axis without impacting the anvil, to the engaged position, in which the hammer impacts the anvil, in response to the rotational speed of the hammer achieving a threshold rotational speed. The controller may be configured to cause the actuator to pivot the hammer from the engaged position to the disengaged position in response to the hammer impacting the anvil. The controller may be configured to sense a rotational position of the hammer about the first axis, sense a rotational position of the anvil about the first axis, and determine when to cause the actuator to pivot the hammer based on the rotational position of the hammer relative to the rotational position of the anvil.
In some embodiments, the controller may comprise a mechanical trigger configured to cause the actuator to pivot the hammer based on a force applied to the mechanical trigger in response to rotation of the hammer. The impact tool may further comprise a hammer frame supporting the hammer for rotation therewith about the first axis, a pivot pin coupled to a first side of the hammer frame, the pivot pin being disposed along the second axis, wherein the hammer includes a pivot groove formed in the outer surface of the hammer opposite the cam groove, the pivot pin being received in the pivot groove of the hammer, and a motor operably coupled to the hammer frame and configured to drive rotation of the hammer frame. The pivot pin of the hammer frame may be configured to rotate about the first axis when rotation of the hammer frame is driven by the motor. The hammer frame may include a channel defined in a second side of the hammer frame opposite the first side, and the actuator may be received in the channel.
According to another aspect, an impact tool may comprise a hammer configured to rotate about a first axis and to pivot about a second axis between a first position and a second position, where the second axis is parallel to and spaced apart from the first axis and the hammer having a void formed therein, and an anvil disposed within the void of the hammer and configured to rotate about the first axis in response to being impacted by the hammer, where the hammer is configured to impact the anvil while in the first position and to rotate freely about the anvil while in the second position.
In some embodiments, the hammer may be configured to impact the anvil while in the first position when rotating about the first axis in a clockwise direction and may be further configured to pivot about the second axis between the second position and a third position and to impact the anvil while in the third position when rotating about the first axis in a counterclockwise direction. The anvil may comprise a cylindrical body and an lug extending outward from the cylindrical body, and the hammer may comprise first and second impact jaws extending into the void formed in the hammer, the first impact jaw being configured to impact the lug of the anvil while the hammer is in the first position and the second impact jaw being configured to impact the lug of the anvil while the hammer is in the third position.
In some embodiments, the impact tool further comprises an actuator coupled to the hammer and configured to pivot the hammer about the second axis between the first, second, and third positions. The hammer may include a cam groove formed in an outer surface of the hammer, and the actuator may comprise a ball bearing that is received in and moves along the cam groove formed in the hammer. The cam groove formed in the hammer may be V-shaped with first and second sections that meet at a vertex, such that the ball bearing of the actuator is positioned at the vertex of the cam groove when the hammer is in the second position, the ball bearing of the actuator is positioned along the first section of the cam groove when the hammer is in the first position, and the ball bearing of the actuator is positioned along the second section of the cam groove when the hammer is in the third position.
According to yet another aspect, an impact tool may comprise a hammer configured to rotate about a first axis and to pivot about a second axis, where the second axis is parallel to and spaced apart from the first axis and the hammer has a void formed therein, an anvil disposed within the void of the hammer and configured to rotate about the first axis when impacted by the hammer, and an actuator positioned along a third axis that is parallel to and spaced apart from both the first axis and the second axis, where the actuator engages the hammer such that movement of the actuator along the third axis causes the hammer to pivot about the second axis.
In some embodiments, the actuator may engage a cam groove formed in an outer surface of the hammer. The actuator may be configured to pivot the hammer about the second axis between a disengaged position and an engaged position. The impact tool may further comprise a spring biasing the actuator along the third axis toward a first position in which the hammer is in the engaged position.
In some embodiments, the impact tool may further comprise an air motor configured to divert a motive fluid to the actuator to overcome a biasing force of the spring to move the actuator along the third axis toward a second position and thereby pivot the hammer to the disengaged position. The impact tool may further comprise a hammer frame supporting the hammer for rotation therewith about the first axis. The hammer frame may include a channel defined therein along the third axis, and the actuator may be received in the channel. The air motor may comprise a rotor operably coupled to the hammer frame to drive rotation of the hammer frame. An air passage may be defined in the rotor and the hammer frame. The air passage may be configured to divert the motive fluid to the channel defined in the hammer frame to move the actuator along the third axis.
The concepts described in the present disclosure are illustrated by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures 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 figures 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 figures 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.
An impact tool (e.g., an impact wrench) generally includes a motor and an impact mechanism configured to convert torque provided by the motor into a series of powerful rotary blows directed from one or more hammers of the impact mechanism to an anvil of the impact mechanism. One illustrative embodiment of an impact mechanism 10 according to the present disclosure is depicted in
Referring now to
The motor 24 includes a rotor 30 (see
As best seen in
As indicated above, the hammer 14 is formed to include a void 34 that receives the anvil 16 when the impact mechanism 10 is assembled. The void 34 is defined by an outer ring 42 of the hammer 14 and a pair of impact jaws 44 that extend inward from the outer ring 42 (toward the axis 22), as shown in
In the illustrative embodiment, a pivot groove 46 and a cam groove 48 are each formed in an outer surface 50 of the hammer 14. In the illustrative embodiment shown in
The pivot pin 20 is coupled to the hammer frame 12 and positioned along an axis 58. As will be appreciated from
As shown in
The actuator 62 further includes a cam 78 that is received in and configured to move along the cam groove 48 of the hammer 14. As further described below, movement of the cam 78 along the cam groove 48 causes the hammer 14 to pivot about the pivot pin 20 (i.e., about the axis 58). In the illustrative embodiment, the cam 78 is embodied as a ball bearing 78 positioned in a recess formed in the actuator 62 such that about half of the ball bearing 78 is exposed. In other embodiments, the cam 78 may be integrally formed with the actuator 62 and embodied as, for example, a semi-spherical protrusion extending outward from an outer surface of the actuator 62. In still other embodiments, the cam 78 may be otherwise sized and/or shaped to movably couple the actuator 62 to the cam groove 48 of the hammer 14.
In the illustrative embodiment, the spring 64 is received in a void 70 defined in the actuator 62 and biases the actuator 62 toward the rear input end 28 of the impact mechanism 10. In other embodiments, the actuator assembly 18 may include other mechanisms for biasing the actuator 62 toward the rear input end 28 of the impact mechanism 10. In still other embodiments, the spring 64 (or another mechanism) may bias the actuator 62 toward the front output end 26 of the impact mechanism 10 (rather than the rear input end 28). The actuator cap 66 is coupled to the hammer frame 12 to cover the channel 60 at the front output end 26, after insertion of the other components of the actuator assembly 18 within the channel 60. The actuator cap 66 may be fastened to the hammer frame 12 using a press fit, taper fit, threading, and/or another fastening mechanism.
Referring now to
When the actuator 62 moves to along the axis 68 (in the illustrative embodiment, when the actuator 62 moves toward the rear input end 28 of the impact mechanism 10, as shown in
As indicated above, the spring 64 biases the actuator 62 toward the rear input end 28 of the impact mechanism 10. Referring now to
When the valve is open, motive fluid will travel through the passageway 80 to reach the actuator 62 and move the actuator 62 (against the bias force of the spring 64) toward the front output end 26 of the impact mechanism 10, as shown in
The impact tool may further include a control system configured to control movement of the actuator 62 and, hence, pivoting of the hammer 14 of the impact mechanism 10. For example, in the illustrative embodiment, the impact tool includes an electronic controller that is configured to open and close the valve, thereby controlling the supply of motive fluid to the actuator 62 and the pivoting of the hammer 14 between the disengaged and engaged positions. The illustrative impact mechanism 10 also includes one or more sensors (not shown) configured to sense, directly or indirectly, various operational characteristics of the impact mechanism 10, which may be used by the electronic controller to determine when to pivot the hammer 14 from the disengaged position to one of the engaged positions. These sensors may be configured to sense, for example, the rotational position of various components of the impact mechanism 10 (e.g., the hammer frame 12, the hammer 14, the anvil 16) and/or the rotational speed at which such components are traveling.
The electronic controller may interpret signals sent by such sensors and may activate or energize electronically-controlled components associated with the impact mechanism 10 (e.g., the valve). In the illustrative embodiment, the electronic controller may be configured to permit the hammer 14 to rotate freely in the disengaged position until a threshold rotational speed of the hammer 14 or other threshold value has been achieved. Once that threshold has been achieved, the controller may instruct the valve (e.g., via electrical signals sent to the valve) to cease supplying motive fluid to the passageway 80 to allow the actuator 62 to move the hammer 14 to the one of the engaged positions to deliver an impact blow to the anvil 16.
The particular attribute and value defining the threshold value may vary depending on the particular embodiment and the particular sensors used. For example, in an embodiment in which the sensors are used to determine the rotational speed of the hammer 14, the controller may compare the sensed speed values to a threshold rotational speed to determine whether the threshold rotational speed has been achieved (i.e., met or exceeded). It will be appreciated that sensed values may be used, for example, to derive other values that may be compared to a threshold. Further, in some embodiments, the controller may determine when to pivot the hammer 14 to the engaged position based on user input such as, for example, a user-selected rotational speed of the hammer 14, a user-selected number of skipped impact blows between the hammer 14 and the anvil 16, or a user-selected elapsed time.
As mentioned above, in some embodiments, the sensors may sense a rotational position of the hammer 14 about the axis 22 and a rotational position of the anvil 16 about the axis 22. The controller may utilize such sensed data to determine when to cause the actuator 62 to pivot the hammer 14. That is, the controller may cause the actuator 62 to pivot the hammer 14 to an engaged position at a point in time that would permit full impact between the impact jaw 44 of the hammer 14 and the lug 40 of the anvil 16 (e.g., to result in a force vector in generally the same direction as the traditional Maurer force vector). In yet another embodiment, the controller may utilize angular data associated with components of the impact mechanism 10 to determine when to pivot the hammer 14 to an engaged position.
It is also contemplated that, in other embodiments, the impact tool may include an entirely mechanical (rather than electromechanical) control system, in which the controller of the impact mechanism 10 includes a mechanical trigger configured to control operation of the valve that supplies motive fluid to the passageway 80. U.S. patent application Ser. No. 14/099,266, filed on Dec. 6, 2013 by the same applicant as the present application and entitled “Impact Tools with Speed Controllers” (the entire disclosure of which is hereby incorporated by reference), describes at least one suitable mechanical trigger in the form of a mechanical speed controller. For example, the speed controller disclosed in that application may be mounted to rotate with (or at a speed proportional to) the hammer 14 such that, in response in response to rotation of the hammer 14, a force is applied to move a plunger of the speed controller. The plunger may be configured to close the valve (e.g., by virtue of moving a predetermined distance) in response to the hammer 14 achieving a threshold rotational speed.
During operation of the impact mechanism 10, the rotor 30 of the motor 24 drives rotation of the hammer frame 12 and thereby drives rotation of the hammer 14 about the axis 22. At the same time, the valve supplies motive fluid to the actuator 62 (via the passageway 80) to overcome the biasing force of the spring 64 and maintain the hammer 14 in the disengaged position, as shown in
After the threshold rotational speed of the hammer 14 has been achieved, the controller causes the valve to cease supplying motive fluid to the passageway 80 and thereby allows the biasing force of the spring 64 to move the actuator 62 toward the rear input end 28 of the impact mechanism 10, as shown in
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. For example, while the impact mechanism 10 has been illustratively shown and described as including one hammer 14, it will be appreciated that the concepts of the present disclosure might also be applied to impact mechanisms including two or more hammers.
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.
