A robot with a noncontact sensor is configured to: perform the predetermined motion in a state where the moving object does not enter, and thereby store, for each of a plurality of measurement points set in a movable range of the robot, an output value of the noncontact sensor as a reference output value in advance, and stop the predetermined motion when the output value of the noncontact sensor changes from the reference output value at the measurement point closest to a current operating position of the robot by a first threshold value or larger when the robot is performing the predetermined motion in a state where the moving object could possibly enter and the current operating position of the robot is in a range in which it is necessary to determine an entering state of the moving object.

Table saws with safety systems are disclosed. The safety systems detect and react to dangerous conditions, such as contact between the blade and a person. The table saws may include a switch, a first light that illuminates to indicate the safety system is operable, and a second light that illuminates to indicate that the safety system is inoperable. The switch may not power the saw when switched on if the second light is illuminated.

An object detection system in a saw includes an electrically conductive plate positioned at a predetermined distance from the implement, a detection circuit comprising a transformer, and a single cable connecting first terminal and second terminals of the transformer. The single cable includes a first conductor electrically connected to the first terminal of the winding and to the electrically conductive plate, a second conductor electrically connected to the implement, and an electrical insulator positioned between the first conductor and the second conductor.

A power tool and methods are provided for detecting objects (e.g., flesh or other materials) in the operating path of a power tool's output component (e.g., saw blade or drill bit). An object detection sensor in the power tool generates an output signal indicative of a type of material detected in the operating path of the power tool. A power tool controller receives the object detection sensor output and determines when a material in the operating path of the power tool changes. The controller changes operation of a motor of the power tool (e.g., increasing or decreasing speed or stopping the motor) in response to the detected material change. The object detection sensor may include, for example, an RF sensor, a capacitive sensor, a camera, a conductivity probe, or an ultrasound probe.

A safety device for monitoring a technical installation with a pressure-sensitive sensor. The pressure sensitive sensor having a plurality of first and second electrodes, wherein each first electrode overlaps each second electrode in an associated coupling site. Furthermore, each first electrode is spaced apart from the associated second electrode in the associated coupling site by a pressure sensitive material. Upon application of a force at the coupling site, an electrical resistance between the associated first and second electrode changes. A measuring circuitry coupled to said plurality of first and second electrodes successively determines the electrical resistance at associated coupling sites. For determining the electrical resistance at a coupling site via the associated first and second electrode, the measuring circuitry connects the further first and second electrodes to a terminal for receiving a defined potential to enable isolated measurement of the electrical resistance at the coupling site.

Power tools with conductive couplings used with active injury mitigation technology are disclosed. Conductive couplings are particularly relevant to table saws, hand-held circular saws, track saws, miter saws, and band saws with active injury mitigation technology. Conductive couplings provide a mechanism through which an electrical signal can be coupled or imparted to a blade, and then monitored for changes indicative of human contact with the blade. An exemplary conductive coupling includes a brush that establishes an electrical connection with a moving part of a power tool, and the brush maintains contact with the moving part of the power tool during at least 40 hours of cumulative time when the motor is spinning the arbor and blade without an interruption in the electrical connection sufficient to trigger the reaction system. A conductive coupling may be two-sided compliant. A conductive coupling may connect to a motor shaft to minimize electrical noise.

A power tool and methods are provided for detecting objects (e.g., flesh or other materials) in the operating path of a power tool's output component (e.g., saw blade or drill bit). An object detection sensor in the power tool generates an output signal indicative of a type of material detected in the operating path of the power tool. A power tool controller receives the object detection sensor output and determines when a material in the operating path of the power tool changes. The controller changes operation of a motor of the power tool (e.g., increasing or decreasing speed or stopping the motor) in response to the detected material change. The object detection sensor may include, for example, an RF sensor, a capacitive sensor, a camera, a conductivity probe, or an ultrasound probe.

A method is provided for detecting a substance, preferably human tissue, in the vicinity of a mobile tool, wherein the substance to be detected has different electrical characteristics from a material that can be processed by the mobile tool. In the method, a change is detected in a capacitance formed by the tool and a counter electrode that is electrically insulated from the tool. A periodic change in the capacitance is detected and the change is produced by the presence of the substance in a region in relation to the tool and by a periodic change in a geometrical characteristic of the tool in this region as the tool moves.

Machines with safety systems are disclosed. The machine may take the form of woodworking machines including table saws, band saws, miter saws, hand-held circular saws, pneumatic chop saws, radial-arm saws, jointers, planars, routers and shapers. The machines may include an operative structure configured to perform a task, where the operative structure includes a cutting tool adapted to move in at least one motion, and a safety system adapted to detect the occurrence of an unsafe condition between a person and the cutting tool and for mitigating the unsafe condition. The safety system may include a detection subsystem and a reaction subsystem. The machine may also include a bypass or override mode where in an injury mitigation system is disabled for certain cuts.

An apparatus for use with an item of personal protective equipment, where the item of personal protective equipment includes a sensor configured to detect when the personal protective equipment is being worn properly by the user. The apparatus is housed within a hand-held power tool that includes a power circuit. The apparatus includes an electrical isolation device configured to prevent current flow in at least one conductor included in the power circuit; a wireless communication device configured to wirelessly couple to a wireless communication device included in the personal protective equipment. The wireless communication device is configured to receive a wireless signal transmitted from the wireless communication device included the personal protective equipment, the wireless signal providing information concerning whether the user is wearing the item of personal protective equipment properly. The electrical isolation device operates to allow current flow in the at least one conductor when the information provided by the wireless signal indicates that the item of personal protective equipment is being worn properly by the user.