Abstract: In accordance with an embodiment of the present invention, a fastening device such as, for example, a forward acting stapler, is provided that includes a manually operable latch in order to store the built up potential energy that results from depressing the handle of the fastening device. Upon actuation of the latch, the plunger within the fastening device is released, thereby converting the stored energy of an internal compression spring into kinetic energy and ejecting a fastener (such as, for example, staples, nails or other types of fasteners) from the staple chamber to fasten an object.

Abstract: A fastener driving tool including a housing enclosing a cylinder having a lower end with a resilient bumper, a return air chamber in communication with the lower end of the cylinder and a piston dimensioned for reciprocation within the cylinder to impact the bumper and having a driver blade depending therefrom. At least one inlet opening is in communication with the return air chamber and at least one outlet opening is disposed in the cylinder and spaced from the at least one inlet opening. The at least outlet opening is in communication with the return air chamber and aligned with the piston so that each outlet opening is closed by the piston to seal the cylinder as the piston impacts the bumper and traps a residual volume of air in the cylinder below the piston to damp impact of the piston upon the bumper.

Abstract: The invention relates to an assembly device (100) and method having a screw device (101) for tightening and loosening screws, having a screw head (102) and a housing (103), wherein measurement errors of an angle measuring device (104) are corrected by means of a detecting unit (105) for detecting erroneous sensor data in the rest state, and more precise and secure tightening of screws of nuts is thereby enabled.

Abstract: A torque-limiting device may include a shaft extending axially through upper and lower shanks and a spring to connect to a nut. The upper and lower shanks may be under a force from the spring and further configured to selectively engage within a predetermined torque limit and disengage at above the predetermined torque limit. Accordingly, the shaft may receive torque up to the predetermined limit as provided by a user operating a handle of the torque-limiting device. The torque-limiting device may be disposable, reusable, economical, and have high torque capabilities.

Abstract: A transportable screwing tool configured to mount and/or dismount screws into and/or out of a work piece includes an electric motor operable by electrical energy and a switching element configured to activate and/or deactivate the electric motor. The screwing tool further includes a drive train arranged inside a housing of the screwing tool. The drive train is mounted pivotably about an axis of rotation arranged essentially perpendicularly to the drive train. A method for activating and/or deactivating the electric motor includes moving at least one element of the switching element for the purpose of activating the electric motor out of a position of nonuse into a position of use when the drive train is moved in rotation about the axis of rotation.

Abstract: A drop hammer for driving a pile comprising a ram member supported within a housing chamber for movement relative to the housing member between the lower position and the upper position and a lifting system for moving the ram member from the lower position to the upper position. When the lifting system raises the ram member above a preload position, ambient air substantially freely flows into and out of the housing chamber through a vent port. When the ram member falls below the preload position, fluid is prevented from flowing through the vent port such that ambient air within a preload chamber portion of the housing chamber compresses to create a preload force that is transmitted to the pile. When the ram member moves into the lower position, an impact force generated by the ram member is transmitted to the pile.

Abstract: An improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; determining a second derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable and the second derivative, each control profile correlating the control input variable of the input unit to a rotational speed at which to drive the output shaft; and driving the output shaft at a rotational speed in accordance with the selected control profile.

Abstract: An improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; receiving at least one tool parameter relating to the power tool; determining a derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable, the derivative of the input control variable, and the tool parameter, each control profile correlating the control input variable of the input unit to a rotational speed at which to drive the output shaft; and driving the output shaft at a rotational speed in accordance with the selected control profile.

Abstract: An electric assembly device for tightening of fastener includes a housing and a rotation. motor which is drivingly connected to an output shaft. The output shaft has a forward portion extending out of the housing, and is adapted to carry a coupling device for releasable coupling with a fastener during tightening, which is to be performed along a first rotation axis. The device is adapted to determine an angular displacement of the housing with respect to the first rotation axis during tightening of the fastener, and to control the rotation speed of the motor during tightening based on the determined angular displacement of the housing.

Abstract: A fastening device includes first to third rotary sensors (position detecting unit) which are provided in a support arm and detect a position of a nut runner (fastening tool), and a main controller (controlling unit) which has a storage unit for storing a plurality of fastening positions of a chain cover, and drives the nut runner when a detection result from the first to third rotary sensors coincides with position information of the fastening position of the chain cover stored by the storage unit. Therefore, during a fastening work, an operator does not need to pull a trigger to drive and rotate the nut runner, thus reducing a burden on the operator during the fastening work.

Abstract: A battering apparatus including a battering element, an air source, a sensing device, a triggering mechanism, and a battering element release mechanism. Engagement of the sensing device activates the triggering mechanism which in turn activated the battering element release mechanism. The battering element is then released, and driven by air from the air source, moved to its extended position, causing the battering head of the battering element to engage an item to be broken.

Abstract: A wedge anchor driver comprising: a first member having a first opening configured to fit onto the nut of a wedge anchor and a second opening configured to receive a predetermined length of the outer end of the wedge anchor's bolt; and a second member associated with the first member, wherein the second member's distal end is configured to fit, and be lockable, into the chuck of a hammer drill, such that, after the wedge anchor driver is locked into the chuck of the hammer drill, a user can drive the wedge anchor into a corresponding hole with the hammer drill in hammer mode and then tighten the nut of the wedge anchor by switching the hammer drill from hammer mode to drill mode.

Abstract: Motorized vehicles having hydraulic tools as attachments are well known. Examples includes road graders, excavators, snow ploughs (and nursery equipment such as tree spades, tree movers and tree handling equipment), tractors, front loaders, and skid steers. A single hydraulic tool may be controlled by a simple manually operated hydraulic control system if the operation of the hydraulic tool is not complex. The use of “Electric over Hydraulic control” is more commonly used for hydraulic attachments with more complex functionality. A typical electric over hydraulic control system uses a bundle of wires; in which each wire in the bundle is dedicated to a particular operational feature of the attachment. These wires are prone to failure as a result of the wear and tear they are exposed to during normal use of the equipment. This, in turn, has led to proposals for the use of a wireless control system.

Abstract: A portable linear fastener driving tool is provided that drive staples, nails, or other linearly driven fasteners. The tool uses a gas spring principle, in which a cylinder filled with compressed gas is used to quickly force a piston through a driving stroke movement, while a driver also drives a fastener into a workpiece. The piston/driver is then moved back to its starting position by use of a rotary-to-linear lifter, and the piston again compresses the gas above the piston, thereby preparing the tool for another driving stroke. The driver has protrusions along its edges that contact the lifter, which lifts the driver during a return stroke. A pivotable latch is controlled to move into either an interfering position or a non-interfering position with respect to the driver protrusions, and acts as a safety device, by preventing the driver from making a full driving stroke at an improper time.

Abstract: An impact wrench which includes an air motor and a main shaft that is rotated by pulsed impact torque that is converted from rotary torque from the air motor to tighten a bolt, is provided with a torque sensor that detects a tightening torque on the bolt, and a controller that performs control functions to tighten the bolt, and the controller changes the rotational speed of the air motor to tighten up the bolt when the tightening torque that is detected by the torque sensor becomes equal to or higher than a prescribed value.

Abstract: A storage-battery-operated screwing tool is controlled by means of an external USB/Bluetooth keyboard.

Abstract: A method and a storage device including a software product for modifying a drilling pattern, and a rock drilling rig. One or more holes whose location is to be changed may be selected from a drilling pattern prior to drilling. The hole is assigned a new location by means of a drilling unit and, subsequently, the drilling pattern is updated.

Abstract: A robot for machining a part of structure under water, comprising a machine tool having a chamber receiving a machining element, a support and guiding structure of the machine tool fixable with respect to the part to be machined and having submersible mobile elements and corresponding submersible guiding elements defining axes along which the mobile elements are movable to position the machine tool with respect to the part to be machined, displacement units for displacement of the mobile elements along the axes, a gas supply connecting to the machine tool to inject gas in the chamber, and a programmable control unit for operating the displacement units and the machine tool based on a closed-loop control mode in order to achieve the machining of the part.

Abstract: Disclosed herein are different embodiments of a fastening device. In particular, various embodiments of a fastening device are described herein for enabling fasteners of different types (e.g. shape and/or size, etc.) to be fastened using a common input drive. For example, different embodiments of the herein described fastening device comprise two or more output sockets in attending to the fastening of different fastener types, which output sockets are selectable in one example by reorienting the fastening device via activation of the input drive.

Abstract: An improved method is provided for operating a power tool. The method includes: monitoring rotational motion of the power tool about an axis using a rotational motion sensor disposed in the power tool; determining a direction of the rotational motion about the axis; and driving the output member in a direction defined by the detected rotational motion of the tool, where the output member is driven by a motor residing in the power tool. Thus, the output member is drive clockwise when the rotational motion of the tool is clockwise about the axis and the output member is drive counter-clockwise when the rotational motion of the tool is counter-clockwise about the axis.

Abstract: A power tool has a housing, an output member coupled to the housing, and a motor, rotational motion sensor, timer, and control circuit in the housing. The timer is initiated, and the rotational motion sensor monitors rotational motion of the housing about an axis. The control circuit determines the direction of the rotational motion of the housing, whether the direction is different from a previous direction of rotational motion of the housing, and whether a value for the timer exceeds a predetermined threshold. If the direction is different from the previous direction and the timer value is less than the predetermined threshold, the control circuit initiates a protective action for the power tool. The control circuit also drives the motor to cause the output member to rotate in a direction that corresponds to the detected rotational motion of the housing.

Abstract: A rock drilling machine with a first control means (21, 22) within a second piston (6) and acting on a first piston (13) such that it counteracts displacement of the relative positions of a first and a second control device at the moment of contact of the second piston onto the drill rod or onto a part (9) connected to this. Furthermore, a rock drill rig comprising such a rock drilling machine and a method for counteracting the said displacement. Significant improvements in reproducibility for impact mechanism stability over long manufacturing series are achieved through the invention. In the same way, the lifetime of rock drilling devices manufactured according to the invention is extended through the impact mechanism acting in a more stable manner despite wear of component parts. It is furthermore possible to dimension for higher rates of impact without risking the impact mechanism stability.

Abstract: Method of determining a direction of a drilling pattern in a tunnel curve calculation to be executed in a control unit of a rock drilling rig, a storage device including software product implementing the method and a rock drilling rig. Tunnel line of a tunnel to be excavated is determined. Location of a drilling site on the tunnel line is communicated to the control unit and a navigation plane of the drilling pattern is positioned on the tunnel line. Start point of a round is positioned on the tunnel line and length of the round is provided. End point of the round is positioned at a distance corresponding with the length of the round from the start point and a coordinate system of the drilling pattern is directed so one of its axes points from the start point to the end point. Finally, different coordinate systems are transformed.

Abstract: A filter turning mechanism is attached to an engine in proximity to a filter (such as an oil filter), and may be used to install or remove a filter by turning the filter. The filter turning mechanism contacts a filter, and rotates the filter when the filter turning mechanism is rotated with a tool. One implementation of the filter turning mechanism includes an inner drive gear and a filter drive mechanism. The inner drive gear normally spins freely within the filter drive mechanism, but when pushed into the filter drive mechanism with a suitable tool such as a ratchet extension, the inner drive gear engages the filter drive mechanism, thereby causing rotation of the inner drive gear to rotate the filter drive mechanism as well, which in turn rotates the filter.

Abstract: A method of modifying a hand-held tool which having a stationary handle actuated by a movable handle connected to a movable tool jaw by a connection linkage, the method including removing the moving handle and the stationary handle. A pneumatic actuator with a piston rod is added. The connection linkage is modified to extend between the piston rod and the movable tool jaw. A trigger is added between the pneumatic actuator and a source of pressurized gas.

Abstract: Screw driver-holder apparatuses, systems and methods are provided and can include a screw and a screwdriver. The screw can include a threaded screw body and a screw head, and the screw head can include a socket and a screw head surface surrounding the socket. The screwdriver can include a hollow sleeve with a longitudinal bore and a first end defining a screw engagement surface and a driving shaft positioned within the longitudinal bore of the hollow sleeve and rotatable relative to the hollow sleeve. The driving shaft can further include a first end extending beyond the first end of the hollow sleeve, a second end opposite the first end, and a stop restricting axial movement of the sleeve towards the second end of the driving shaft. The first end can include a protruding tip adapted for engaging the socket of the screw head.

Abstract: A finger operable, reverse drive holder tool includes an annular knob or handle with a one-way clutch axially retained within the handle and capable of removably receiving a selected holder having a uniform or standard sized body which is insertable into the one-way clutch and may be easily removed and reversed by insertion into the opposite side of the one-way clutch.

Abstract: [Problem to be Solved] To provide an air hammer tool which largely reduces transmission of vibration to a worker, has a simple and light-weight structure, can he manufactured at a low cost, and can be easily maintained. [Solution] An air hammer tool.

Abstract: An apparatus and method for deep earth grounding includes positioning a power driver at a site, the power driver comprising a frame and an impact hammer operatively connected to the frame, adjusting placement of the impact hammer, raising the impact hammer, driving 10 foot sectioned grounding rods down into the ground at the site using the hammer, testing resistance, and determining if more additional grounding rods are necessary based on the resistance. A power driver device includes an open frame, guide rails operatively connected to the frame, an impact hammer operatively connected to the guide rails and moveable along the guide rails, and a hand crank assembly operatively connected to the frame and configured for raising the guide rails and the impact hammer up and down along the frame.

Abstract: A pneumatic power tool with a housing assembly, a pneumatic motor assembly, an output member, and a trigger assembly. The housing assembly has a body, a cap member and a gasket assembly. The body defines a motor cavity and an inlet manifold. The cap member defines an air inlet port. The gasket has a first portion being a band formed of a compressible material and a second portion formed of a porous material. The band of the first portion is sealingly abutted against the body and cap member. The pneumatic motor assembly is received in the motor cavity defined by the body. The output member is driven by the pneumatic motor assembly. The trigger assembly is coupled to the housing assembly and is operable for selectively operating the pneumatic motor assembly. Pressurized air received into the air inlet port is filtered by the second portion of the gasket assembly and flows into the inlet manifold when the pneumatic motor assembly is operated. A related method is also provided.

Abstract: A power tool with an epicyclically or so called planet gear system with two annulus gears, at least one solar gear with external toothing, and planet wheels having two toothed rings which each mesh with one of the annulus gears. A planet carrier holding the planet wheels. The gear is interchangeable between an at least first configuration and second configuration, wherein the planet carrier is interchangeable between being locked or partly locked rotationally to the frame or being unlocked rotationally from the frame.

Abstract: A power tool that includes a pipe holder, a knife pivotally coupled to the pipe holder, and a drive mechanism coupled to at least one of the pipe holder and the knife. The power tool also includes a motor coupled to a drive mechanism, and a removable and rechargeable battery pack coupled to the motor to selectively provide power signals to the motor. The power tool also includes a controller configured to monitor a plurality of conditions of the power tool, such as battery pack voltage, battery pack temperature, operational current, and the like. The controller is also configured to detect one or more events related to the plurality of conditions of the power tool. For example, the controller is configured to monitor the operational current of the power tool. If the operational current of the power tool exceeds a first threshold value, a power signal duty cycle is reduced from a first duty cycle value to a second duty cycle value to limit the amount of torque the power tool is able to generate.

Abstract: An improved method is provided for operating a power tool. The method includes: monitoring rotational motion of the power tool about an axis using a rotational motion sensor disposed in the power tool; determining a direction of the rotational motion about the axis; and driving the output member in a direction defined by the detected rotational motion of the tool, where the output member is driven by a motor residing in the power tool. Thus, the output member is drive clockwise when the rotational motion of the tool is clockwise about the axis and the output member is drive counter-clockwise when the rotational motion of the tool is counter-clockwise about the axis.

Abstract: The invention relates to a novel screw tensioning device with a screw tensioning cylinder with a high-pressure hydraulic pump for pretensioning screws and loosening extremely secure pretensable screw connections and an accompanying control method. The problem is to create a screw tensioning device that can generate high tensioning forces, that requires less energy, that can be used for all usage locations without problems, that can be easily controlled and that makes precisely controlled pretensioning possible. A high-pressure hydraulic pump 39 is integrated into the interior of the screw tensioning cylinder 38 in accordance with the invention. This high-pressure pump 39 is connected to a sealed hydraulic accumulator 42. A drive unit 40 that can be pneumatically actuated is arranged on or in the screw tensioning cylinder 38. The drive unit 40 can be designed on the constructional basis of a diaphragm cylinder 42 or on the basis of a piston cylinder.

Abstract: A method for operating a driving tool, such as a fastening tool, that has a driver, a motor assembly with a motor and an output member, and an electrical power source. The methodology includes transmitting electrical power to the motor to rotate the output member and thereafter adjusting one or more control parameters if a rotational speed of the output member is not within a predetermined operating range.

Abstract: An adjustable socket wrench extension includes a gear train of meshing gears that translates torque from a first end to a second, opposite end; a female drive fitting to apply the torque from the socket wrench to the first end of the gear train; a male drive fitting to provide the torque to a socket at the second end; a frame that retains the gear train in a plane; a plurality of locking plates on the first side of the frame; a locking tab on the first side of the frame to retain the locking plates in a relative orientation; and a pushbutton on the second side of the frame to temporarily disengage the locking tab from the locking plates so that the relative orientation between the plates may be changed, thereby changing the shape of the device.

Abstract: A machining method comprises selecting a finished surface dimension and a material property for a working surface, defining a working temperature range based on the selected material property, and defining a machining power based on the working temperature range. The machining power depends on a removal rate and a specific heat of the working surface. The working surface is machined at the removal rate to achieve the finished surface dimension, and the machine power is controlled to maintain the working surface within the working temperature range. The working surface is heated or cooled from the working temperature range to a transition temperature range, such that the selected material property is preserved in the working surface.

Abstract: Impact tool and method for a hammer device that includes impact tool housing and tubular piston structured and arranged for axial displacement in impact tool housing via pressure medium. Tubular piston has essentially radial pressure surfaces structured and arranged on opposite portions of tubular piston to be acted on with pressure medium. Grooves are formed in impact tool housing that are structured and arranged for a reversal of a direction of a pressure medium impingement on pressure surfaces and discharge or recirculation of medium. Grooves include a control recess formed in tubular piston and at least two control grooves for a shift of pressure medium impingement on pressure surfaces that are arranged axially offset in impact tool housing. A controller is structured and arranged to alternatively activate one of the at least two control grooves via connection channels.

Abstract: An improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; determining a derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable and the derivative, each control profile correlating the control input variable of the input unit to a rotational speed at which to drive the output shaft; and driving the output shaft at a rotational speed in accordance with the selected control profile.

Abstract: The present disclosure provides a drill drive unit and drill string make up and break up unit with a method for use with a dual pipe drill string configuration. The drill drive unit is mounted to a single carriage and includes an outer drive spindle in a position fixed to the carriage with inner drive spindle configured to rotate independent of the outer drive spindle while being able to move longitudinally at least 12 inches relative to the outer drive spindle. The method involves connecting and disconnecting inner shafts and outer shafts of the dual pipe drill string.

Abstract: A construction apparatus having an extendable mast with an upper mast element longitudinally displaceable relative to a lower mast element. A linear drive displaces the mast elements relative to each other, and has an upper drive part linearly actuable relative to a lower drive part of the linear drive, and a locking device for locking the two mast elements in an extended mast position. The upper drive part is fixable to the upper mast element, the lower drive part of the linear drive is displaceable longitudinally of the lower mast element and a securing device is provided on the lower mast element, with which the lower drive part is releasably securable to the lower mast element for displacement of the upper mast element. A method for operating a construction apparatus with an extendable mast can be carried out with a construction apparatus in accordance with the invention.

Abstract: To adjust a length of each leg of a staple projected to a back side of sheets of paper 5 to be bound according to a thickness thereof. In an electric stapler containing a head portion 2 including a forming plate 12 that forms a straight staple 9a so as to be U-shaped and a driver plate 13 that ejects the formed staple, a cartridge including staple sheets stacked with multiple layers, and a stapler main body which supplies the staple sheet below the forming plate 12 and which contains a driving portion that drives the forming plate 12 and the driver plate 13 in the head portion 2, plural head portions 2 are provided in which the forming plate 12 and the driver plate 13 inside have width lengths different from each other, wherein each head portion 2 is attachable to and detachable from the stapler main body.

Abstract: The present invention provides a power tool for tightening a fastener. The power tool includes a motor, a hammer, an anvil, and a control unit. The hammer is intermittently or continuously rotatable in a forward direction by the motor. The anvil is impacted by the hammer rotated in the forward direction. The control unit controls the hammer to continuously rotate at a first number of rotations, and to intermittently rotate at a second number of rotations lower than the first number of rotations when a prescribed time has elapsed from the rotation of the hammer at the first number of rotations, and then to intermittently rotate at a third number of rotations lower than the second number of rotations when a predetermined time has elapsed from the rotation of the hammer at the second number of rotations.

Abstract: A portable linear fastener driving tool is provided that drive staples, nails, or other linearly driven fasteners. The tool uses a gas spring principle, in which a cylinder filled with compressed gas is used to quickly force a piston through a driving stroke movement, while a driver also drives a fastener into a workpiece. The piston/driver is then moved back to its starting position by use of a rotary-to-linear lifter, and the piston again compresses the gas above the piston, thereby preparing the tool for another driving stroke. The driver has protrusions along its edges that contact the lifter, which lifts the driver during a return stroke. A pivotable latch is controlled to move into either an interfering position or a non-interfering position with respect to the driver protrusions, and acts as a safety device, by preventing the driver from making a full driving stroke at an improper time.

Abstract: The present invention provides multi-directional oscillation from a rotational source, by receiving a rotational motion, converting the rotational motion to a first oscillating motion, converting the first oscillating motion to a second oscillating motion that is normal to the first oscillating motion and transferring the first oscillating motion and the second oscillating motion to a working element.

Abstract: The present invention provides an axial machining device comprising a tool-carrier spindle rotatable in a housing, the housing housing a transmission system causing the spindle to advance automatically relative to the housing under the effect of the tool-carrier spindle being driven in rotation, the transmission system including an advance gearwheel screwed onto the spindle, the device including a resilient return member urging the advance gearwheel in a first axial direction opposite to the advance direction of the spindle, and also including a first rolling bearing having rolling members rolling on an undulating raceway having an axial component, thereby periodically urging the advance gearwheel to move in a second direction opposite to the first, such that rotation of the spindle is accompanied by axial vibratory motion.

Abstract: A surgical device includes a first jaw and a second jaw moveable relative to the first jaw between a first position, in which the first and second jaws are aligned within a plane, and a second position, in which the second jaw is in non-parallel correspondence to the plane. The surgical device may include a surgical member, e.g., a cutting and/or stapling element, disposed within the first jaw, and a second driver configured to cause relative movement of the surgical member in a direction parallel to the plane. The first and second jaws may include a camming arrangement that is configured to move the second jaw between the first and second positions. The camming arrangement may include a channel disposed along at least a portion of one or both of the first and second jaws, a ball bearing disposed within the channel.

Abstract: A control scheme is provided for a power tool having a rotary shaft. The control scheme includes: monitoring rotational motion of the tool generally about a longitudinal axis of the shaft; detecting a condition of the tool based on the rotational motion of the tool; and controlling torque imparted to the shaft upon detecting the tool condition, where the torque is inversely related to an angular displacement of the tool about the longitudinal axis of the shaft.

Abstract: An electric stapler is operated by a paper bundle pinching step of relatively moving a table part and a driver unit and also pinching a paper bundle; a staple separation step of folding a staple into U-shape by a forming plate and also separating the folded U-shape staple from a staple sheet by moving a driver; a penetration step of penetrating legs of the staple into the paper bundle by further moving the driver; a clinch step of inward folding the legs by a clinch device; and a paper bundle releasing step. A relative movement of the table part and the driver unit, the forming plate, the driver, and the clinch device are powered by a single motor. A driving speed of the motor in the steps excluding the penetration step and the clinch step is slower than the driving speed of the motor in the penetration step and the clinch step.

Abstract: A control system is provided for use in a power tool. The control system includes: a rotational rate sensor having a resonating mass and a controller electrically connected to the rotational rate sensor. The rotational rate sensor detects lateral displacement of the resonating mass and generates a signal indicative of the detected lateral displacement, such that the lateral displacement is directly proportional to a rotational speed at which the power tool rotates about an axis of the rotary shaft. Based on the generated signal, the controller initiates a protective operation to avoid further undesirable rotation of the power tool. The controller may opt to reduce the torque applied to shaft to a non-zero value that enables the operator to regain control of the tool.