The present disclosure relates, generally, to impact tools and, more particularly, to a mechanism that measures the angular velocity of components in the impact tool.
An illustrative embodiment of the present disclosure provides an impact tool which comprises: an impact force generation unit that includes a hammer that is movable in a first direction and which applies a rotational impact force on an anvil that rotates the output drive; a first hammer angle sensor set to a first signal channel and located proximate to a surface of the hammer, and a second hammer angle sensor set to a second signal channel and located proximate to the surface of the hammer and adjacent to first hammer angle sensor; a plurality of regularly spaced targets located on the surface of the hammer; wherein each of the plurality of regularly spaced targets are detectable by the first and second hammer sensors; wherein detection of one or more of the plurality of regularly spaced targets by the first and second hammer sensors indicates movement of the hammer; a first anvil angle sensor set to a third signal channel and located proximate to a surface of the anvil, and a second anvil angle sensor set to a fourth signal channel and located proximate to the surface of the anvil and adjacent to first anvil angle sensor; a plurality of regularly spaced targets located on the surface of the anvil; wherein each of the plurality of regularly spaced targets on the anvil are detectable by the first and second anvil sensors; wherein detection of one or more of the plurality of regularly spaced targets on the anvil by the first and second anvil sensors indicates movement of the anvil that resulted from an impact force created when the hammer struck the anvil; and a controller that receives and processes a plurality of signals generated by the first and second hammer angle sensors and the first and second anvil angle sensors.
Another illustrative embodiment of the present disclosure provides an impact tool which comprises: a drive source configured to rotate an output drive; an impact force generation unit that includes a hammer that is movable in a first direction to apply a rotational impact force on an anvil which rotates the output drive; a first hammer angle sensor set to a first signal channel located proximate to a surface of the hammer, and a second hammer angle sensor set to a second signal channel also located proximate to the surface of the hammer and adjacent to first hammer angle sensor; a plurality of regularly spaced targets located on the surface of the hammer; wherein each of the plurality of regularly spaced targets are detectable by the first and second hammer sensors; wherein detection of one or more of the plurality of regularly spaced targets by the first and second hammer sensors indicates rotation of the hammer; and a controller configured to receive and process a plurality of signals generated by the first and second hammer angle sensors to determine the angular velocity of the output drive.
In the above and other illustrative embodiments, the impact tool may further include any one or more of the following: the first and second hammer sensors being configured to detect movement of the hammer in a second direction opposite the first direction after the hammer impacts the anvil; an anvil angle sensor and a plurality of regularly spaced anvil targets mounted on a surface of the anvil; the anvil angle sensor being located proximate to the surface of the anvil, wherein each of the plurality of regularly spaced anvil targets are detectable by the anvil angle sensor, and wherein the controller being configured to receive and process a plurality of signals also generated by the anvil angle sensor to determine the angular velocity of the output drive; a three axis gyroscopic sensor mounted within a tool housing portion of the impact tool, wherein the three axis gyroscopic sensor detects housing rotation about an axis coincident with an axis of rotation of the output drive, and wherein the controller being configured to receive gyroscopic signals to assist in determining the angular velocity of the output drive; the each of the plurality of regularly spaced targets is selected from the group consisting of a plurality of ferromagnetic markings, capacitive markings, optical markings, and physically or electronically perceptible markings; an accelerometer that sends a signal to the controller to detect an impact between the hammer and anvil; a motor sensor that sends a signal to the controller to detect motor output torque; a transmitter that wirelessly transmits signal from the impact tool; data storage to store data received by the controller; a selector switch for setting socket size; at least one strain gage on the anvil to measure the torque generated by the anvil; and an at least 20 amp lithium battery.
An illustrative embodiment of the present disclosure provides an impact tool which comprises: a drive source configured to rotate an output drive; a hammer that is movable in a first direction to apply a rotational impact force on an anvil which rotates the output drive; a first hammer angle sensor set to a first signal channel and located proximate to a surface of the hammer; a plurality of regularly spaced targets located on the surface of the hammer; wherein each of the plurality of regularly spaced targets are detectable by the first hammer sensor; and wherein detection of one or more of the plurality of regularly spaced targets by the first hammer sensor indicates movement of the hammer.
In the above and other illustrative embodiments, the impact tool may further include any one or more of the following: a controller configured to receive and process a plurality of signals generated by the first hammer angle sensor to determine the angular velocity of the hammer; a second hammer angle sensor set to a second signal channel also located proximate to the surface of the hammer and adjacent to first hammer angle sensor; the first and second hammer sensors being configured to detect rotation of the hammer in a second direction opposite the first direction after the hammer impacts the anvil; an anvil angle sensor and a plurality of regularly spaced anvil targets mounted on a surface of the anvil; the anvil angle sensor is located proximate to the surface of the anvil, wherein each of the plurality of regularly spaced anvil targets being detectable by the anvil angle sensor, and wherein the controller is configured to receive and process a plurality of signals also generated by the anvil angle sensor to determine the angle and velocity of the output drive; and a three axis gyroscopic sensor mounted within a tool housing portion of the impact tool, wherein the three axis gyroscopic sensor detects housing rotation about an axis coincident with an axis of rotation of the output drive, and the controller being configured to receive gyroscopic signals to assist in determining the angle and velocity of the output drive.
Additional features and advantages of the impact tool angular velocity measurement mechanism will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrated embodiments exemplifying best modes of carrying out the impact tool angular velocity measurement mechanism as presently perceived.
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.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates embodiments of the impact tool angular velocity measurement mechanism, and such exemplification is not to be construed as limiting the scope of the impact tool angular velocity measurement mechanism in any manner.
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.
An illustrative embodiment of the present disclosure provides electronic detectors, encoders, or sensors (referred to general as detectors) added to at least the hammer, and a controller to monitor the function of an impact wrench. In another embodiment the detectors are added to both the hammer and the anvil. These detectors monitor anvil rotation and hammer velocity. These signals are processed by a controller which determines the incremental bolt angle that occurs during each impact between the hammer and anvil. The controller then calculates the quantity of energy that has been delivered to the fastener.
An embodiment of the angular velocity measurement mechanism may include, but is not limited to, one or more of the following features: measuring the forward hammer velocity just prior to impact between the hammer and anvil and reverse velocity immediately after impact between the hammer and anvil to determine the amount of energy that left the tool during impact; measuring the sudden change of rate of angular velocity of the anvil used to detect when an impact between the hammer and anvil has occurred; measuring the incremental anvil angle associated with a single impact between the hammer and anvil to determine the fastener or bolt rotation from that impact; and measuring the cumulative anvil angle used during a fastening cycle to determine total angle the fastener or bolt was rotated.
Using a hammer encoder signal generated by the detectors directed to the hammer, the controller calculates hammer velocity before and after each impact between the hammer and anvil. Given the rotational velocity of the hammer, and the rotational inertia of the hammer, it is possible to calculate the angular kinetic energy in the hammer illustratively by the formula one-half multiplied by the angular velocity multiplied by the moment of inertia squared
These velocity measurements may then be used to determine how much energy has left the impact mechanism and transmitted forward into the socket.
The angle of rotation of the fastener or bolt may be determined by measuring the angle of rotation of the impact tool's anvil. Since the tool anvil and bolt head are directly connected by the socket, the angle of rotation of the bolt should be substantially the same as that of the anvil. Using an anvil angle encoder signal generated by the detector, the controller may calculate both the incremental angle that occurs during each impact, and the cumulative angle of anvil rotation of the bolt.
A cross-sectional view of an illustrative embodiment of an impact tool 2 is shown in
Aspects of the present disclose may be included on impact tools of the type disclosed in U.S. Pat. No. 9,597,784, “Impact tools”, issued Mar. 21, 2017; U.S. Pat. No. 9,592,600 “Angle impact tools” issued Mar. 14, 2017; U.S. Pat. No. 9,573,254, “Impact tools”, Feb. 21, 2017; U.S. Pat. No. 9,555,532, “Rotary Impact Tool”, issued Jan. 31, 2017; U.S. Pat. No. 9,550,284 “Angle Impact Tool”, issued Jan. 24, 2017; U.S. Pat. No. 9,486,908, “, “Rotary Impact Tool”, issued Nov. 8, 2016; U.S. Pat. No. 9,272,400, “Torque-limited Impact Tool”, issued Mar. 1, 2016; U.S. Pat. No. 9,022,888, “Angle Impact Tool”, issued May 5, 2015; U.S. Pat. No. 8,925,646, “Right Angle Impact Tool” issued Jan. 6, 2015; U.S. Pat. No. 7,673,702, “Impact wrench”, issued Mar. 9, 2010; and U.S. Pat. No. 7,562,720, “Electric motor impact tool”, issued Jul. 21, 2009. The disclosures of which, including their structures and mechanisms of operation, are herein incorporated by reference. It will be appreciated by the skilled artisan upon reading this disclosure that the foregoing incorporated impact tool references can be used in the present disclosure. The common thread is the rotating hammer striking the anvil. It is further appreciated any other mechanism that produces the rotating hammer and anvil mechanism is intended to be included herein and is part of the scope of this disclosure.
As part of impact tool 2, a plurality of detectors such as detector 30 shown in
Similarly, in an illustrative embodiment, another detector set 36 and 37 may be attached to hammer case 34 or like structure. Detectors 36 and 37 are located in proximity of a portion of anvil 26 (see, also,
Also shown in
A front perspective view of impact tool 2 with a portion of its hammer case 34 removed is shown in
An isolated exploded view of hammer 14 and anvil 26 are shown in
Similarly, surface 52 of anvil 26 includes a plurality of markings 54 that are regularly spaced thereabout and configured to be read by detectors 36 and 37 are illustratively composed of two channels. Detectors 36 and 37 may operate similar to that described with respect to detectors 30 and 32. In some illustrative embodiments, anvil 26 may be extended either axially or radially to accommodate the markings, and to ensure sufficient proximity between surface 52 and detectors 36 and 37.
It is also illustratively shown in
It is further appreciated that impact tool 2 may include a three axis gyroscopic sensor located thereon. This sensor measures the rotation of the housing about axis 24. Illustratively, the three axis gyroscopic sensor may be part of the circuit board of controller 33. To that end, controller 33 may be configured to receive these signals from the hammer, anvil, and gyroscopic sensor to determine the angular velocity of the hammer and/or anvil. And because the anvil, through the connected output drive, is connected to the fastener or bolt, the rotational velocity of the fastener or bolt can be determined as well.
An accelerometer may be added to the circuit board of controller 33 on impact tool 2 in order to send a signal to controller 33 indicative of an impact between the hammer and anvil. It will be appreciated by a skilled artisan that the accelerometer may be mounted anywhere inside the tool housing in proximity to the impact mechanism. The shock wave created by the impact action of the mechanism is transmitted within the housing and creates a detectable spike in the output of the accelerometer. This signal may be used by the controller as an indication that an impact has occurred.
A motor current transducer sensor may be added to the circuit board of controller 33 and configured to send an input signal to controller 33. Motor current is proportional to motor torque and can be used to determine how much torque is being delivered to the gearing and impact mechanisms. Controller 33, whether located on impact tool 2 or spaced apart, is contemplated to be configured to include storage for these signals received from such detectors.
Impact tool 2 may include a user interface that includes a display, push buttons, audible notifications, and/or LED lighting, for example, to allow adjustment of the functional settings for the impact tool. A selector switch may be attached to impact tool 2 in order to allow individual socket size setting. Further, strain gages may be attached to the anvil to measure torque of same.
A graph of the hammer angle signal 64 and anvil angle signal 66 values plotted against time is shown in
The portion of time represented in
After the fastener stops rotating at 76, 78, 80, and 81 the portion of energy temporarily stored in the connected output drive applies a torque to drive the anvil and hammer in the reverse direction 50. Both the hammer and anvil rotate in the reverse direction briefly, until the torque delivered by the motor overcomes the inertia in the hammer and causes it to begin rotating in the forward direction again. This series of steps describe the process of impacting. The anvil and hammer angle signals are sent to controller 33, and can be used to determine many different attributes about the operation of the impact mechanism. Some of the attributes that can be calculated include hammer energy before impact, hammer energy after impact, deflection of the connected output drive, rebound velocity of the connected output drive, and rebound velocity of the hammer. These attributes can be used to calculate the status of bolt torque during the fastening process. Controller 33 can make the decision to stop the motor when a targeted torque has been reached.
The isolated detailed views of hammer 14 and anvil 26 engaging in an impact along with the corresponding chart positions from
Hammer 14 continues rotating illustratively in direction 48 and in direction 86 until, as shown in
As depicted in
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.