Power tool safety system

A safety system, for use with a power tool, includes a sensor assembly and a controller. The power tool includes a base and a moving component that is movable relative to the base. The sensor assembly monitors a predetermined danger zone that is adjacent to the moving component of the power tool. The sensor assembly is configured to generate data relating to the predetermined danger zone. The controller receives the data from the sensor assembly and analyzes the data from the sensor assembly to determine if at least a portion of a hand of the user is present within the predetermined danger zone. The safety system can further include a wearable component including infrared only reflective material that is coupled to the hand of the user. The controller analyzes the data from the sensor assembly to determine if the wearable component is present within the predetermined danger zone.

BACKGROUND

Power tools of many varieties are used by millions of individuals on a regular or periodic basis. Unfortunately, power tools can be very dangerous if used improperly or just by their inherent nature. For example, a power tool such as a power saw or power drill can easily and potentially severely injure the hand or fingers of a user, including loss of digits and worse, if the hand or fingers get too close to and/or contact the saw blade or drill bit during use of the power tool. As a further example, when using a power saw, the user physically holds an object to be cut and moves the object into the moving saw blade so that the object can be cut. This inherently places the user at risk of contacting the saw blade in the event of slipping or as a result of inattention. While guards can be used to cover portions of the saw blade, a portion of the saw blade still remains exposed to the user.

Thus, it is desired to provide a safety system for use with power tools that can effectively inhibit or at least mitigate the severity of injury to the user during use of the power tools. More specifically, in certain applications, it is desired to provide a safety system for use with power tools that will automatically shut down (or power off) the power tool and rapidly stop movement of moving components of the power tool if the hand or fingers of the user get too close to the moving components of the power tool.

SUMMARY

The present invention is directed toward a safety system for use with a power tool that is usable by a user, the power tool including a base and a moving component that is movable relative to the base. In various embodiments, the safety system includes a sensor assembly and a controller. The sensor assembly monitors a predetermined danger zone that is adjacent to the moving component of the power tool. The sensor assembly is configured to generate data relating to the predetermined danger zone. The controller receives the data from the sensor assembly and analyzes the data from the sensor assembly to determine if at least a portion of a hand of the user is present within the predetermined danger zone.

In some embodiments, the safety system further includes a wearable component that is configured to be coupled to the hand of the user. The wearable component includes infrared only reflective material. In such embodiments, the controller analyzes the data from the sensor assembly to determine if the wearable component is present within the predetermined danger zone. In certain such embodiments, the wearable component includes black infrared only reflective material.

Additionally, in certain embodiments, the sensor assembly includes a first sensor that monitors a first region that is adjacent to the moving component of the power tool and generates first data relating to the predetermined danger zone, and a second sensor that monitors a second region that is adjacent to the moving component of the power tool and generates second data relating to the predetermined danger zone. In such embodiments, the controller compares the first data from the first sensor and the second data from the second sensor to determine if the wearable component is present within the predetermined danger zone. In some such embodiments, the first region intersects the second region to define a common region, and the predetermined danger zone is based on the common region.

In some embodiments, the first sensor is a first sensor type and the second sensor is a second sensor type that is different than the first sensor type. For example, in one such embodiment, the first sensor is a red blue green input device, and wherein the second sensor is a no infrared filter input device.

Additionally, in certain embodiments, the safety system further includes a braking system that is configured to selectively stop movement of the moving component of the power tool relative to the base. In such embodiments, if the controller determines that the wearable component is present within the predetermined danger zone, the controller transmits a signal to the braking system to stop movement of the moving component of the power tool relative to the base.

Alternatively, in other embodiments, the sensor assembly includes a first sensor that captures at least one hand image prior to the user using the power tool, and a second sensor that monitors the predetermined danger zone that is adjacent to the moving component of the power tool and generates the data relating to the predetermined danger zone. In such embodiments, the controller generates a detection algorithm that is based at least in part on the at least one hand image that is captured by the first sensor prior to the user using the power tool. Additionally, the controller analyzes the data from the second sensor utilizing the detection algorithm to determine if the at least a portion of the hand of the user is present within the predetermined danger zone. Further, in some such embodiments, the first sensor captures a plurality of hand images prior to the user using the power tool; and the controller generates the detection algorithm based at least in part on the plurality of hand images that are captured by the first sensor prior to the user using the power tool.

In certain embodiments, the first sensor is the same as the second sensor.

Further, in some embodiments, the safety system further includes a braking system that is configured to selectively stop movement of the moving component of the power tool relative to the base. In such embodiments, if the controller determines that the at least a portion of the hand is present within the predetermined danger zone, the controller transmits a signal to the braking system to stop movement of the moving component of the power tool relative to the base.

The present invention is further directed toward a method for protecting a hand of a user during use of a power tool, the power tool including a base and a moving component that is movable relative to the base, the method including (i) monitoring a predetermined danger zone that is adjacent to the moving component of the power tool with a sensor assembly; (ii) generating data relating to the predetermined danger zone with the sensor assembly; (iii) receiving the data from the sensor assembly with a controller; and (iv) analyzing the data from the sensor assembly with the controller to determine if at least a portion of a hand of the user is present within the predetermined danger zone.

DESCRIPTION

Embodiments of the present invention are described herein in the context of a power tool safety system (also sometimes referred to herein simply as a “safety system”) for protecting a user during use of a power tool. In various embodiments, the safety system is configured to inhibit and/or minimize injury to the user during use of the power tool, e.g., by automatically shutting down and/or ceasing movement of a moving component of the power tool when certain conditions are sensed. More specifically, in such embodiments, the safety system can be configured to sense, recognize and/or identify the presence of a portion of the user, e.g., a hand or a portion of a hand of the user, within a predetermined area that is positioned near to, adjacent to, and/or substantially encircles the moving component of the power tool. The safety system can further automatically shut down and stop operation of the power tool upon sensing, recognizing and/or identifying the portion of the user within the predetermined area that is positioned near to, adjacent to, and/or substantially encircles the moving component of the power tool.

Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings.

FIG. 1Ais a simplified schematic front view illustration of a power tool10, and a portion of an embodiment of a power tool safety system12(also referred to herein simply as a “safety system”) having features of the present invention that is usable with the power tool10.

As provided herein, the safety system12can be used with any suitable power tool10. For example, in certain non-exclusive alternative applications, the safety system12can be used with a band saw, a table saw, a circular saw, a miter saw, or a drill press. Alternatively, the safety system12can be used with any other suitable power tool10. Thus, although various Figures provided herewith illustrate the safety system12being used specifically with a band saw, such use is not intended to be limiting in any manner.

As shown inFIG. 1A, the power tool10includes a base14and a moving component16, e.g., a saw blade or a drill bit, that is movable relative to the base14. In particular, during use of the power tool10, the power tool10can be moved between a non-operating condition, where the moving component16is not moving relative to the base14, and an operating condition, where the moving component16is moving relative to the base14so as to enable the power tool10to perform its desired function. Additionally, as illustrated, the power tool10can further include an on/off (power) switch18that can be selectively activated by a user20(illustrated inFIG. 1D) to selectively move the power tool10between the non-operating condition (i.e. the “off” condition) and the operating condition (i.e. the “on” condition). Further, in certain embodiments, the power tool10can also include a safety cutoff switch22that can be selectively activated by the user20for manually activating a braking system for rapidly stopping movement of the moving component16relative to the base14. The safety cutoff switch22is also usable to selectively energize and de-energize the power tool10and the safety system12.

As noted above, the safety system12is configured to protect the user20, i.e. to inhibit and/or minimize injury to the user20, during use of the power tool10. In various embodiments, the safety system12is configured to automatically shut down the power tool10, i.e. by automatically stopping movement of the moving component16relative to the base14, when certain conditions exist and/or are sensed in relation to the power tool10.

The design of the safety system12, and the positioning of the various components of the safety system12can be varied to suit the specific requirements of the power tool10with which the safety system12is being used. In various embodiments, the safety system12can be configured to include one or more of a wearable component24(illustrated, for example, inFIG. 1D), a sensor assembly26, a controller28, and a braking system30. Alternatively, it is understood that the safety system12can include additional components or fewer components than what is illustrated in the Figures. For example, in certain non-exclusive alternative embodiments, the safety system12can be configured for use without the specific need for the wearable component24. Still alternatively, one or more of the components of the safety system12can be positioned in a different manner than what is shown in the Figures.

As provided herein, in various embodiments, the wearable component24is configured to be coupled to and/or worn by the user20during use of the power tool10. The wearable component24can be provided in any suitable form for use by the user20. In various embodiments, the wearable component24is configured to cover at least a portion of a hand20A (illustrated inFIG. 1D) of the user20. For example, in some such embodiments, as shown inFIG. 1D, the wearable component24can be provided in the form of a glove that is to be worn on the hand20A of the user20, and covers substantially the entirety of the hand20A of the user20, during use of the power tool10. Alternatively, the wearable component24can be configured to be worn by the user20such that it covers less than the entirety of the hand20A of the user20. For example, in one non-exclusive alternative embodiment, the wearable component24can be provided in the form of a finger-tip cover that is configured to be worn on only a single finger-tip20B (illustrated inFIG. 2) of the hand20A of the user20.

Additionally, the wearable component24can be formed from any suitable materials and/or can be any suitable colors. As provided herein, in various embodiments, the wearable component24is made from materials and/or includes colors that can be sensed and/or identified by the safety system12, i.e. the sensor assembly26and/or the controller28. For example, in certain embodiments, the wearable component24can include an infrared only reflective material or pigment, e.g., a black infrared only reflective material. Alternatively, the wearable component24can be formed from or include different materials and/or different colors than those specifically noted herein, provided that such materials and/or colors can be readily sensed or identified by the sensor assembly26and/or the controller28.

The sensor assembly26is configured to sense and/or detect the presence of the wearable component24, and thus the presence of at least a portion of the hand20A of the user20, i.e. in a position near and/or adjacent to the moving component16of the power tool10. In some embodiments, the sensor assembly26is coupled to the power tool10such that the sensor assembly26is substantially fixed in position relative to the power tool10, i.e. at least relative to the base14of the power tool10, during use of the power tool10. More particularly, in alternative such embodiments, the sensor assembly26can be fixedly coupled to the power tool10or the sensor assembly26can be removably coupled to the power tool10. Still alternatively, the sensor assembly26can be provided independently from the power tool10, but can still be configured to be fixed in position relative to the power tool10, i.e. at least relative to the base14of the power tool10, so as to be effectively usable with the power tool10.

The design of the sensor assembly26can be varied to suit the requirements of the safety system12. In the embodiment illustrated inFIG. 1A, the sensor assembly26includes a first sensor26A and a second sensor26B that are each positioned and configured to monitor and/or sense within an area or region that is positioned near to, adjacent to, and/or that substantially encircles the moving component16of the power tool16. In certain embodiments, the first sensor26A can be a first sensor type, and the second sensor26B can be a second sensor type that is different than the first sensor type. For example, in one such embodiment, the first sensor26A can be a red blue green (RBG) input device, e.g., camera or other suitable input device, that is positioned and oriented to monitor a first region32A, e.g., to capture images (pixels) within the first region32A, that is positioned near to, adjacent to, and/or that substantially encircles the moving component16of the power tool10; and the second sensor26B can be a no infrared filter (NoIR) input device, e.g., a camera or other suitable input device, that is positioned and oriented to monitor a second region32B, e.g., to capture images (pixels) within the second region32B, that is positioned near to, adjacent to, and/or that substantially encircles the moving component16of the power tool10. Additionally, as provided herein, the first sensor26A and the second sensor26B can be further configured to generate data relating to the first region32A and the second region32B, respectively, that can be transmitted to the controller28. Alternatively, the first sensor26A and/or the second sensor26B can have a different design.

It is appreciated that the use of the terms “first sensor” and “second sensor” is merely for convenience and ease of illustration, and either sensor526A,526B can be referred to as the “first sensor” and/or the “second sensor”.

In certain embodiments, the controller28can be coupled to the power tool10, i.e. to the base14of the power tool10. Alternatively, the controller28can be provided remotely from the power tool10.

As provided herein, the controller28is configured to receive and analyze input (e.g., data) from the sensor assembly26, e.g., the images (pixels) captured by the first sensor26A and the second sensor26B, to determine when the wearable component24is within a predetermined danger zone34(also sometimes referred to herein as the “danger zone”) that is established near to, adjacent to, and/or that substantially encircles the moving component16of the power tool10. As such, the controller28can analyze the input, data and/or images from sensors26A,26B to determine when at least a portion of the hand20A of the user20is within the predetermined danger zone34. With such design, the sensor assembly26and/or each of the sensors26A,26B can be said to be usable for monitoring the predetermined danger zone34.

Additionally, during use of the power tool10and the safety system12, the controller28can be used in what is sometimes referred to herein as a “glove-sensing mode” or “component-sensing mode”, as well as what is sometimes referred to herein as a “collision detection mode”. For example, when the controller28is in a mode for determining when the wearable component24is within the predetermined danger zone34, but the power tool10is not running, then the controller28can be said to be in the glove-sensing mode or the component-sensing mode. Conversely, when the controller28is in a mode for determining when the wearable component24is within the predetermined danger zone34, and the power tool10is running, then the controller28can be said to be in the collision detection mode.

As described in greater detail herein below, it is appreciated that in embodiments of the safety system12that do not include the wearable component24, the sensor assembly26can be configured to sense and/or detect the presence of the hand20A of the user20(or at least a portion of the hand20A of the user20) in a position near and/or adjacent to the moving component16of the power tool10. Further, in such embodiments, the controller28can be configured to receive and analyze input (data) from the sensor assembly26to determine when the hand20A of the user20(or at least a portion of the hand20A of the user20) is within the predetermined danger zone34near and/or adjacent to the moving component of the power tool10.

The controller28and the circuitry provided therewith can have any suitable design. For example, in some embodiments, the controller28includes a single board computer (SBC) having one or more processors or circuits for purposes of analyzing the input, data and/or images (i.e. the pixels within the corresponding regions32A,32B) generated and/or captured by the first sensor26A and the second sensor26B.

Additionally, in certain embodiments, the controller28can incorporate one more visual outputs, e.g., LED lights, that alert the user20regarding the status of the power tool10and/or the safety system12. For example, in such embodiments, the controller28can include visual outputs indicative that the power tool10is in a no start (non-operating) condition, a can start condition, and a running (operating) condition; as well as a visual output regarding activation of the safety system12, i.e. identifying a collision detection when the wearable component24is determined to be within the danger zone34. In certain embodiments, it is further appreciated that the safety system12and/or the controller28can be configured to sense or monitor movement of the user20, e.g., at least a portion of the hand20A of the user20, near or within the predetermined danger zone34. For example, in some such embodiments, the safety system12and/or the controller28can be configured to sense or detect movement of at least a portion of the user20above a predetermined velocity generally toward the moving component16of the power tool10, when such movement is at least is close proximity to the predetermined danger zone34.

Further, the controller28can incorporate the use of any system of electrical connections, e.g., relays, General Purpose Input/Output (GPIO) connections, etc., for purposes of electrically connecting the controller28with the sensor assembly26and the braking system30, as well as electrically connecting various components within the controller28.

The general concept of sensing and/or identifying when the wearable component24and/or at least a portion of the hand20A of the user20may be positioned within the danger zone34will now be described. In particular, utilizing an RGB input device as the first sensor26A enables the controller28to receive as input the full color spectrum of the area near, adjacent to and/or substantially encircling the moving component16of the power tool10. Conversely, the NoIR input device as the second sensor26B contains a no infrared filter and produces a near gray scale image (with infrared backlighting) of the area near, adjacent to and/or substantially encircling the moving component16of the power tool10. Thus, the infrared reflective material that is included on the wearable component24will appear black in the region32A monitored by the first sensor26(e.g., the RGB camera frame) and bright white in the region32B monitored by the second sensor26B (e.g., the NoIR camera frame).

During use of the safety system12, both sensors26A,26B are aligned to a central origin in front of the moving component16of the power tool10with their x and y axes being parallel, respectively. During initial pixel capture, the first region32A monitored by the first sensor26A and the second region32B monitored by the second sensor26B are substantially similar in size and shape and can intersect, overlap and/or coincide for a majority of the respective regions32A,32B. Subsequently, the images (pixels) captured by the first sensor26A and the second sensor26B within the first region32A and the second region32B, respectively, can be cropped and upsampled as necessary in order to equalize and align the coverage of each sensor26A,26B in pixel space, i.e. to provide a common region32C (illustrated inFIG. 1C). In order to achieve the sensing of the infrared reflective material from the wearable component24, the controller28can use the following algorithm:

For each pixel received by the first sensor26A (i.e. the RGB camera), if the red, green or blue values exist outside of the black family of colors (in one non-exclusive representative embodiment, R, G or B values no higher than 60 for any individual value and with a variance no higher than 30 for an 8-bit color value [0-255]), then the pixels are ignored. This eliminates colors other than black that may have change high enough between the two sensors26A,26B to pass the delta test.

Somewhat similarly, for each pixel received by the second sensor26B (i.e. the NoIR camera), if the red, green or blue values exist outside of the white family of colors (in one non-exclusive representative embodiment, R, G or B values no lower than 210 for any individual value and with a variance no higher than 40 for an 8-bit color value [0-255]), then the pixels are ignored. Again, this is done to lower false positives in the delta test.

Since some pixels may still be left with values that exist inside of the acceptable ranges for each sensor26A,26B that are not the intended material of the wearable component24, a pixel-for-pixel comparison can be made seeking a high delta value. More particularly, the algorithm seeks to find what areas of the captured images (pixels) have changed from pure black to pure white between the first sensor26A (e.g., the RGB camera) and the second sensor (e.g., the NoIR camera), while still accepting some color that may reflect off the material of the wearable component24. At this point, the noted areas are now defined as containing the wearable component24that includes and/or has been coated in, for example, the infrared reflective material.

Subsequently, to determine if a collision has occurred, i.e. to see if the wearable component24has actually extended to within the danger zone34, the following algorithm is utilized:

Upon determination that the wearable component24has indeed entered into the predetermined danger zone34, then the controller28generates an appropriate signal to so indicate. Further, the controller28can then transmit the signal to the braking system30to activate the braking system30.

The braking system30is configured to selectively and rapidly stop movement of the moving component16of the power tool10upon receipt of a proper signal from the controller28. More particularly, with specific use of the safety system12, the braking system30is configured to selectively and rapidly stop movement of the moving component16of the power tool10upon receipt of a signal from the controller28that the wearable component24is within the predetermined danger zone34while the power tool10is running.

The braking system30can have any suitable design. Additionally, the safety system12can be configured such that the braking system30is effectively activated, i.e. by an appropriate signal from the controller28, and operated at any desired speed to inhibit injury to the user20. For example, in one non-exclusive embodiment, the braking system30can be effectively activated and operated at a reaction time braking speed of approximately 1.2 meters per second. Such a reaction time braking speed should be sufficient to inhibit injury to the user20in almost all working situations. Alternatively, the braking system30can be configured to be activated and operated at another suitable reaction time braking speed.

In summary, as measured from an origin of the predetermined danger zone34, if any pixel defined as representing the material of the wearable component24comes closer to the origin than the distance of a radius of the danger zone34, then it is determined by the controller28, i.e. through application of the algorithms noted above, that the wearable component24has entered the danger zone34. A signal, e.g., a GPIO signal, is then generated and sent, thus actuating the braking system30.

When the signal is transmitted to the braking system30so as to actuate the braking system30, the safety system12, i.e. the sensor assembly26and the controller28, is said to be working in collision detection mode. Additionally, as noted above, the safety system12, i.e. the sensor assembly26and the controller28, can also be used in the glove-sensing mode (or component-sensing mode). Stated in another manner, utilizing the sensing algorithm used for collision detection, the safety system12also is able to sense the presence of the wearable component24of the user20prior to the power tool10being switched on. As such, the safety system12requires the presence of the wearable component24on the focal plane before the power tool10can be energized. The wearable component24is considered present when their collection of grouped and sensed pixels (in no more or less than two groups) equates to an area predefined as the two-dimensional surface area of the wearable component24(as viewed from above) with hands flat on the focal plane. A GPIO controlled relay that allows current to reach the on/off switch18is then energized for a predetermined amount of time, during which time the power tool10can be turned on. If the predetermined time elapses prior to the power tool10being turned on, then the relay is de-energized and the safety system12waits for the wearable component24to be re-presented. In certain embodiments, at the motor, an additional relay is in place that is actuated by the motor current. The additional relay acts for sensing of a running condition on the power tool10. This additional relay allows the SBC of the controller28to seamlessly swap between the glove-sensing mode and the collision detection mode.

Thus, in certain embodiments, the power tool10is only startable, e.g., via the on/off switch18, once the user20introduces the wearable component24within the region that is monitored and/or sensed by the sensor assembly26. At such time, the controller28is considered to be in the “glove-sensing mode”. Alternatively, in other embodiments, the power tool10can be started by the user20without the need to initially introduce the wearable component24within the region that is monitored and/or sensed by the sensor assembly26.

FIG. 1Bis a simplified schematic side view illustration of the power tool10, and the portion of the power tool safety system12illustrated inFIG. 1A. More specifically,FIG. 1Bprovides another view of the power tool10and the safety system12of the present invention, and the operational features and components thereof. For example,FIG. 1Bagain illustrates the base14and the moving component16of the power tool10, and the sensor assembly26(illustrated in phantom), the controller28(illustrated in phantom) and the braking system30(illustrated in phantom) of the safety system12.

FIGS. 1C and 1Dmore clearly illustrate the regions32A,32B that are captured by the first sensor26A (illustrated inFIG. 1A) and the second sensor26B (illustrated inFIG. 1A), respectively, and the determination of the danger zone34in the area near to, adjacent to, and/or that substantially encircles the moving component16of the power tool10. In particular,FIG. 1Cis a simplified schematic top view illustration of a portion of the power tool10and the power tool safety system12illustrated inFIG. 1A. It is appreciated that certain portions of the power tool10and certain portions of the safety system12have not been illustrated inFIG. 1Cfor purposes of clarity. Additionally,FIG. 1Dis a simplified schematic top view illustration of a portion of the user20, i.e. the hand of the user20, and a portion of the power tool10and the power tool safety system12illustrated inFIG. 1A. It is again appreciated that certain portions of the power tool10and certain portions of the safety system12have not been illustrated inFIG. 1Dfor purposes of clarity.

As shown inFIG. 1C, the first sensor26A is configured to monitor the first region32A, e.g., to capture images (pixels) within the first region32A, and the second sensor26B is configured to monitor the second region32B, e.g., to capture images (pixels) within the second region32B. For simplicity, the first region32A and the second region32B are illustrated inFIG. 1Cas being substantially rectangular in shape. However, it is appreciated that in certain alternative embodiments, the first region32A and/or the second region32B can be other than substantially rectangular-shaped. For example, in some non-exclusive alternative embodiments, one or both of the regions32A,32B can be substantially circle-shaped, oval-shaped, or some other shape.

Additionally,FIG. 1Cfurther illustrates that the intersection and/or overlap between the first region32A and the second region32B, e.g., along the work surface on the base14of the power tool10, defines a common region32C that is further utilized for defining the predetermined danger zone34(illustrated inFIG. 1D) that is positioned near to, adjacent to, and/or substantially encircles the moving component16of the power tool10. Stated in another manner, the predetermined danger zone34can be based on the common region32C.FIG. 1Calso illustrates that the first region32A can have a first mutually exclusive region32D and the second region32B can have a second mutually exclusive region32E, with each mutually exclusive region32D,32E being separate from (i) one another, and (ii) the common region32C. More specifically, in one embodiment, as shown inFIG. 1D, the danger zone34can be defined and/or predetermined by extending a radius in all directions from an origin within the common region32C. Alternatively, the danger zone34can be predetermined within the common region32C in a somewhat different manner.

Further, as noted above,FIG. 1Dalso shows the user20, i.e. the hand20A of the user20, with the wearable component24positioned thereon. As shown, the wearable component24has just extended within the predetermined danger zone34, and thus should be readily detectable by the safety system12, i.e. by the sensor assembly26and the controller28.

FIG. 2is a simplified schematic top view illustration of a portion of the user20, i.e. the hand20A of the user20, a portion of the power tool10, and a portion of another embodiment of the power tool safety system212. It is appreciated that certain portions of the power tool10and certain portions of the safety system212have not been illustrated inFIG. 2for purposes of clarity.

As shown inFIG. 2, the power tool10is again a band saw, although it is appreciated that the power tool10can be any suitable power tool that is usable with the safety system212. More specifically,FIG. 2again illustrates at least the base14and the moving component16of the power tool10.

Additionally, the safety system212is substantially similar to the safety system12that was illustrated and described herein above. For example, the safety system again includes the sensor assembly (not shown inFIG. 2), the controller228, and the braking system (not shown inFIG. 2) that are substantially similar in overall design and function to what was illustrated and described above. However, the wearable component224that is utilized in the embodiment shown inFIG. 2is somewhat different in design as compared to the previous embodiment. In particular, in this embodiment, the wearable component224is configured to only cover one finger-tip20B on the hand20A of the user20, rather than having a glove-like design that covers the entire hand20A of the user20. Further, the wearable component224is again made from and/or includes material that can be sensed by the sensors26A,26B (illustrated, for example, inFIG. 1A) of the sensor assembly for purposes of identifying when the wearable component224(and thus at least a portion of the hand20A of the user20) enters the danger zone234near, adjacent to and/or that substantially encircles the moving component16of the power tool10during use of the power tool10.

FIGS. 3 and 4are flowcharts showing representative examples of use of the power tool in conjunction with the power tool safety system. It is understood that the representative examples disclosed herein can include greater or fewer steps than those shown and described relative toFIGS. 3 and 4. Stated another way, the representative examples described in accordance with the present invention can omit one or more steps illustrated inFIGS. 3 and 4, or can add additional steps not shown and described inFIGS. 3 and 4, and still fall within the purview of the present invention. Further, the sequence of the steps can be varied from those shown and described relative toFIGS. 3 and 4. Thus, it is appreciated that the specific sequence of steps illustrated inFIGS. 3 and 4is not intended to limit the sequencing of steps in any manner.

Referring initially toFIG. 3,FIG. 3is a flowchart illustrating a representative example of a use of the power tool in conjunction with the power tool safety system. In particular,FIG. 3illustrates an example of a use of the power tool where the sensor assembly and/or the controller does not sense the presence of the wearable component within the danger zone that surrounds the moving component of the power tool.

At step301, a user gathers materials to be used during use of the power tool, e.g., the materials to be modified, such as pieces of wood to be cut, during use of the power tool, and makes adjustments to the settings of the power tool as necessary for typical and/or desired use of the power tool.

At step303, the user pulls the safety cutoff switch on the power tool, thereby energizing the power tool and the controller. At such time, in certain embodiments, the controller, i.e. the single board computer (SBC), enters into a glove-sensing mode.

At step305, the user puts on the wearable component, e.g., the glove, and then presents the wearable component on the work surface of the power tool such that the wearable component is sensed by the sensor assembly.

At step307, based on the sensing of the wearable component on the work surface, the on switch relay for the power tool is energized.

At step309, the user presses the on/off (start) button and the power tool begins to run.

At step311, with the start-up of the power tool, the controller, i.e. the SBC, changes into collision detection mode (at run time).

At step313, the user then passes the materials to be modified, e.g., the pieces of wood to be cut, to the power tool in a typical manner.

At step315, the user presses the on/off (stop) button on the power tool to stop the running of the power tool. At this point, the power tool allows the user to turn the power tool back on for a predetermined period of time (at which point the controller, i.e. the SBC, would return to the glove-sensing mode). However, it is also appreciated that upon pressing of the on/off button, the collision detection mode may continue to run for a specified period of time to account for machine slow down and stop time.

At step317, the user presses the safety cutoff switch and the power tool and the safety system are de-energized.

FIG. 4is a flowchart illustrating another representative example of a use of the power tool that is used in conjunction with the power tool safety system. In particular,FIG. 4illustrates an example of a use of the power tool where the sensor assembly and/or the controller does sense the presence of the wearable component within the danger zone that surrounds the moving component of the power tool.

At step401, a user gathers materials to be used during use of the power tool, e.g., the materials to be modified, such as pieces of wood to be cut, during use of the power tool, and makes adjustments to the settings of the power tool as necessary for typical and/or desired use of the power tool.

At step403, the user pulls the safety cutoff switch on the power tool, thereby energizing the power tool and the controller. At such time, in certain embodiments, the controller, i.e. the single board computer (SBC), enters into a glove-sensing mode.

At step405, the user puts on the wearable component, e.g., the glove, and then presents the wearable component on the work surface of the power tool such that the wearable component is sensed by the sensor assembly.

At step407, based on the sensing of the wearable component on the work surface, the on switch relay for the power tool is energized.

At step409, the user presses the on/off (start) button and the power tool begins to run.

At step411, with the start-up of the power tool, the controller, i.e. the SBC, changes into collision detection mode (at run time).

At step413, the user then passes the materials to be modified, e.g., the pieces of wood to be cut, to the power tool in a typical manner.

At step415, while the user is passing the materials to be modified to the power tool, the wearable component that is being worn by the user passes into the danger zone surrounding the moving component of the power tool.

At step417, the sensor assembly and the controller sense the presence of the wearable component in the danger zone surrounding the moving component of the power tool, and a signal is generated and transmitted to the braking system such that the braking system is engaged to rapidly stop movement of the moving component relative to the base of the power tool, and power to the motor of the power tool is cut.

At step419, the movement of the moving component relative to the base of the power tool is arrested prior to contact between the wearable component and the moving component.

At step421, the user re-presents the wearable component on the work surface of the power tool such that the wearable component is sensed by the sensor assembly, and the on switch relay for the power tool is again energized.

At step423, the user continues to pass the materials to be modified, e.g., the pieces of wood to be cut, to the power tool in a typical manner.

At step425, the user presses the on/off (stop) button on the power tool to stop the running of the power tool. At this point, the power tool allows the user to turn the power tool back on for a predetermined period of time (at which point the controller, i.e. the SBC, would return to the glove-sensing mode). However, it is also appreciated that upon pressing of the on/off button, the collision detection mode may continue to run for a specified period of time to account for machine slow down and stop time.

At step427, the user presses the safety cutoff switch and the power tool and the safety system are de-energized.

In summary, the safety system12of the present invention, as described in detail herein, is designed to arrest the motion of a moving component16on a power tool10, e.g., a blade on a cutting tool, prior to contact with the user20. For example, in various embodiments, utilizing a single board computer (SBC) and a red green blue (RGB) input device and no infrared filter (NoIR) input device pair, the motion of a wearable component24coated in black infrared only reflective material can be sensed within a predetermined danger zone34near, adjacent to and/or substantially encircling the moving component16. Upon sensing the infrared reflective material of the wearable component24having entered into the danger zone34, a GPIO signal is sent to a relay that actuates a push/pull solenoid; thus engaging a mechanical braking system30to rapidly stop movement of the moving component16.

Additionally, as provided herein, the safety system12of the present invention provides various unique features applicable during operation of the power tool10with which the safety system12is being used. For example, in certain embodiments, the safety system12provides features such as (i) utilizing a camera array, biased by infrared filtering, to detect an infrared only reflective material or pigment; (ii) utilizing the large change in color (as opposed to the existence of color) at a moment in time to distinguish the item of interest, e.g., the wearable component24and/or at least a portion of the hand20A of the user20; (iii) utilizing a synchronized camera array to detect presence of the user20, e.g., via the wearable component24, within a danger zone34, and thus signaling for activation of the braking system30to stop movement of the moving component16of the power tool10; (iv) utilizing an infrared only reflective pigment coated wearable component24to identify the presence in the user20in the work area and the danger zone34around the moving component16; and (v) forcing the user20to present the wearable component24on the work surface of the power tool10as proof of presence of the user20or wearable component24before the power tool10can be switched to the operating (running) condition.

Further, as noted above, in certain embodiments of the present invention, the safety system need not include the wearable component. For example,FIG. 5Ais a simplified schematic front view illustration of the power tool10, and a portion of still another embodiment of the power tool safety system512. Additionally,FIG. 5Bis a simplified schematic top view illustration of a portion of the user20, i.e. a hand20A of the user20, a portion of the power tool10, and a portion of the power tool safety system512illustrated inFIG. 5A. It is appreciated that certain portions of the power tool10and certain portions of the safety system512have not been illustrated inFIG. 5Aand/orFIG. 5Bfor purposes of clarity.

As above, the power tool10can again be a band saw, a table saw, a circular saw, a miter saw, a drill press, or any other suitable power tool. Additionally, as with the previous embodiments, the power tool10includes the base14and the moving component16, e.g., a saw blade or a drill bit, that is movable relative to the base14. Further, the power tool10can also include an on/off (power) switch18and a safety cutoff switch22that are substantially identical in design and function as described in greater detail herein above.

Additionally, as illustrated inFIGS. 5A and 5B, the safety system512is somewhat similar to the previous embodiments, but does not include the wearable component that was included within the previous embodiments. More specifically, as illustrated in this embodiment, the safety system512can be configured to include one or more of a sensor assembly526, a controller528and a braking system530.

Referring initially toFIG. 5A, as with the previous embodiments, the sensor assembly526is configured to sense and/or detect the presence of at least a portion of a hand20A of the user20in a position near and/or adjacent to the moving component16of the power tool10. The design of the sensor assembly526can be varied to suit the requirements of the safety system512. In this embodiment, as shown inFIG. 5A, the sensor assembly526includes a first sensor526A and a second sensor526B. Alternatively, in other embodiments, the sensor assembly526can include only a single sensor, or the sensor assembly526can be configured to use greater than two sensors.

During use of the safety system512, the first sensor526A is configured to function as a training sensor that is utilized to capture at least one hand image, and preferably a plurality of hand images (pixels). More particularly, as provided herein, the hand images as captured by the first sensor526A are subsequently used for training purposes, i.e. to build a model of the hand and/or to train the controller528to recognize the presence of a hand20A within a particular region. It is appreciated that the model of the hand can also be referred to as and/or function as at least a portion of a detection algorithm that is usable within the controller528Alternatively, it is appreciated that in certain embodiments, the safety system512and/or the sensor assembly526need not include the first sensor526A, and suitable hand images gathered from any suitable source may be provided to the controller528, i.e. to build a model of the hand20A (a detection algorithm) and/or to train the controller528to recognize the presence of a hand20A within a particular region.

In some embodiments, as shown inFIG. 5A, the first sensor526A can be positioned spaced apart from the power tool10and can function independently of the power tool10when being used to capture hand images to build the virtual model of the hand and/or to generate the desired detection algorithm. Alternatively, in other embodiments, the first sensor526A can be coupled to the power tool10.

During capture of the hand images, e.g., with the first sensor526A, it is desired to capture as many hand images as deemed necessary to effectively represent a broad spectrum of potential hand positions, shapes, colors and sizes. For example, in various applications, it can be desired to capture sufficient hand images to be able to effectively identify key points on hands such as joint locations, finger-tips, palm markers, and/or other identifiable key points. With the effective capture of sufficient hand images to identify such key points on the hand, a model of the hand (detection algorithm) can be effectively built which is subsequently usable to identify the presence of a hand within a particular region, i.e. based on comparison of images captured within the region with the hand images used to build the model and/or the model of the hand (detection algorithm) itself. Additionally, it is appreciated that such key points on the hands can be predicted and retrained as necessary to increase the accuracy of the model (detection algorithm). Once the model has been effectively built, the model (detection algorithm) can be loaded into the controller528for use during hand detection applications associated with use of the safety system512while the power tool10is in use. More particularly, as described in greater detail herein below, during run time of the power tool10, the controller528can utilize the uploaded model (detection algorithm) to predict if and where key points of a hand20A are present within a predetermined danger zone534(illustrated inFIG. 5B). Stated in another manner, if key points of a hand20A are found in images within a region, e.g., within a region532(illustrated inFIG. 5B) of the second sensor526B, they are analyzed with the controller528in collision detection mode to determine if the key points, or significant areas between them, have entered into the predetermined danger zone534.

In certain applications, the hand(s) utilized for capturing hand images with the first sensor526A for building the model can be a representative hand520A of a representative user520of the power tool10, and/or the hand can be the hand of one or more other suitable persons. Additionally, in various applications, it is desired to utilize hand images of hands of various shapes, sizes and colors, so that the model (detection algorithm) is usable to effectively detect the presence of a hand20A of any user20of the power tool10. Alternatively, in other applications, it is appreciated that any suitable hand images can be utilized.

In summary, in certain embodiments, the first sensor526A can be configured to operate within a neural network that is trained with a significant number of hand images representing a broad spectrum of hand positions, shapes, colors and sizes. With such design, the first sensor526A can be utilized capture various hand images that are sufficient to build a comprehensive model of the hand, i.e. a comprehensive detection algorithm.

As shown, in various embodiments, the second sensor526B can be coupled to the power tool10and can be positioned and oriented to monitor a region532near, adjacent to and/or that substantially encircles the moving component16of the power tool10. For simplicity, the region532is illustrated inFIG. 5Bas being substantially rectangular in shape. However, it is appreciated that in certain alternative embodiments, the region532can be other than substantially rectangular-shaped. For example, in some non-exclusive alternative embodiments, the region532can be substantially circle-shaped, oval-shaped, or some other shape.

Additionally, as above, the region532can then be utilized for defining the predetermined danger zone534that is positioned near to, adjacent to, and/or substantially encircles the moving component16of the power tool10. Stated in another manner, the predetermined danger zone534can be based on the region532. More specifically, in one embodiment, the danger zone534can be defined and/or predetermined by extending a radius in all directions from an origin within the region532. Alternatively, the danger zone534can be predetermined within the region532in a somewhat different manner. However defined, the predetermined danger zone534is then utilized for purposes of determining if and when at least a portion of the hand20A of the user20has entered into the danger zone534. As such, the safety system512, i.e. the sensor assembly526and/or the controller528, can be said to be configured to monitor the predetermined danger zone534that is positioned near to, adjacent to, and/or substantially encircles the moving component16of the power tool10.

It is appreciated that in certain embodiments, the second sensor526B can also be used and/or function as the training sensor that captures the initial hand images that are used for building the model of the hand. As such, some embodiments can be designed without the specific need for the first sensor526A as described herein, and the sensor assembly526may only include a single sensor, i.e. the second sensor526B. Thus, in such embodiments, the second sensor526B may be described as and/or can function as both the first sensor and the second sensor.

The design of the first sensor526A and the second sensor526B can be varied. For example, in certain embodiments, each of the first sensor526A and the second sensor526B can be a red blue green (RBG) input device, e.g., camera or other suitable input device, such as described above. More specifically, in such embodiments, the first sensor526A can be a red blue green (RBG) input device that is used to capture various hand images for building a virtual model of the hand; and the second sensor526B can be a red blue green (RBG) input device that is used to monitor the region532that is positioned near to, adjacent to, and/or substantially encircles the moving component16of the power tool10. Alternatively, one or both of the first sensor526A and the second sensor526B can have another suitable design.

As above, the use of the terms “first sensor” and “second sensor” is merely for convenience and ease of illustration, and either sensor526A,526B can be referred to as the “first sensor” and/or the “second sensor”.

In certain embodiments, the controller528can be coupled to the power tool10, i.e. to the base14of the power tool10. Alternatively, the controller528can be provided remotely from the power tool10.

In the embodiment illustrated inFIGS. 5A and 5B, the controller528is configured to receive and analyze input (data) from the sensor assembly526, i.e. the hand images (pixels) captured by the first sensor526A that are used to build the virtual model of the hand, and the data generated by (e.g., images captured by) the second sensor526B to determine when at least a portion of the hand20A is within the predetermined danger zone534that is defined near to, adjacent to, and/or substantially encircling the moving component16of the power tool10. Stated in another manner, the hand images, i.e. as captured by the first sensor526A or otherwise provided to the controller528, are utilized to generate a model of the hand including at least one key point, and preferably a plurality of key points of the hand. Such model is then usable by the controller528to determine whether a hand20A of a user20has entered into the predetermined danger zone534, e.g., by analyzing images of the region532as captured by the second sensor526B.

As above, the controller528and the circuitry provided therewith can have any suitable design. For example, in some embodiments, the controller528includes a single board computer (SBC) having one or more processors or circuits for purposes of analyzing the data generated by (e.g., images captured by) the first sensor526A and/or the second sensor526B.

Additionally, in certain embodiments, the controller528can incorporate one more visual outputs, e.g., LED lights, that alert the user20regarding the status of the power tool10and/or the safety system512. For example, in such embodiments, the controller528can include visual outputs indicative that the power tool10is in a no start (non-operating) condition, a can start condition, and a running (operating) condition; as well as a visual output regarding activation of the safety system512, i.e. identifying a collision detection when at least a portion of the hand20A is determined to be within the danger zone534.

Further, the controller528can incorporate the use of any system of electrical connections, e.g., relays, General Purpose Input/Output (GPIO) connections, etc., for purposes of electrically connecting the controller528with the sensor assembly526and the braking system530, as well as electrically connecting various components within the controller528.

Further, as noted above,FIG. 5Balso shows the user20, i.e. the hand20A of the user20, having just extended within the predetermined danger zone534. Thus, the hand20A of the user20should be readily detectable by the safety system512, i.e. by the sensor assembly526and the controller528.

As above, if a collision to the danger zone534is detected, i.e. if at least a portion of the hand20A is detected within the danger zone534, a signal is sent from the controller528to engage the braking system530to rapidly arrest the motion of the moving component16of the power tool10. Conversely, if a collision to the danger zone534is not detected, i.e. if at least a portion of the hand20A is not detected within the danger zone534, the power tool10and the safety system512continue normal operation without generating a signal to activate the braking system530.

During use of the power tool10with such safety system512as illustrated and described herein, the following steps can occur: (i) the user20turns on the controller528, i.e. the SBC, by pulling the safety cutoff switch22on the power tool; (ii) the controller528loads (with the model of the hand20A as generated) and begins to search for hands within the region532of the second sensor526B that is mounted above the work surface, i.e. the base14of the power tool10; (iii) the user20turns the power tool10on (e.g., selectively activates the blade of the band saw); (iv) active collision detection begins; (v) the user20presents materials to the work surface, e.g., wood to be cut with the moving component16, or blade, of the band saw10; (vi) the hand20A of the user20may enter the work surface at any point in the above process, and if the hand20A of the user20enters the danger zone534, the controller528generates a signal that is sent to the braking system530to shut down or arrest the motion of the power tool10, but if the hand20A of the user20remains outside of the danger zone534(i.e. is not detected within the danger zone534), operation of the power tool10continues as normal; (vii) the user20then shuts off the power tool10(as above, it is appreciated that collision detection may continue to run for a specified period of time to account for slow down and stop time of the power tool10); and (viii) the user20shuts off the safety cutoff switch22, and in turn the controller528and collision detection are turned off.

In summary, in the embodiment shown inFIGS. 5A and 5B, the safety system512includes a neural network that is trained with a significant number of hand images representing a broad spectrum of hand positions, shapes, colors and sizes in order to generate a virtual model of the hand (i.e. a detection algorithm) that is utilized to determine at least one, and preferably multiple key points on the hand20A. The hand model is then rendered in the region532of the second sensor526B and utilized in a collision detection mode to determine if a hand20A has entered into the predetermined danger zone534.

It is appreciated that for proper use of this embodiment of the safety system512, certain factors must be complied with: (i) Training of the detection system must occur prior to run time. In other words, the unit is fully trained and retrained prior to installation onto the controller528(SBC); (ii) Once on the controller528(SBC), the detection model should not change by retraining as this may lead to a drop in accuracy. In other words, the unit never retrains only on the specific hands of a user; (iii) During initial training of the model, key points may be found in error of actual key point locations. These key points can be manually corrected and the prediction model rerun until a significantly accurate detection platform is achieved; and (iv) As provided herein, in this embodiment, a glove or other wearable component is not required to train or detect a hand; however it may be used to reduce the amount of training that the system requires. For example, if a gloved hand is the sole method of training, the glove will then be required for detection. It is appreciated that this decision, i.e. whether the unit is to be trained on a gloved hand or a non-gloved hand, will have to be made prior to beginning programming of the unit.

It is understood that although a number of different embodiments of the power tool safety system have been illustrated and described herein, one or more features of any one embodiment can be combined with one or more features of one or more of the other embodiments, provided that such combination satisfies the intent of the present invention.