Snap-on Inc.

Michael T Rajzer

Jason Genz

Joshua M Beer

Craig Brouwers

Christoffer S Fox

Daniel Nitzsche

Isidro M Alanis

An illumination source disposed in a housing of a tool without the need for fasteners or snaps. The illumination source includes a number illumination elements, such as LEDs, disposed on a circuit board. A lens and the housing cooperatively direct light emitted by the illumination elements away from a user's eyes during use of the tool.

Tool illumination source

The present invention relates to a method of commutation control of a brushless DC (BLDC) motor. The method uses a controller to control the BLDC motor using a modified six-step commutation. The method adds six intermediate steps that overlap the six-step commutation. Each of the six steps overlap with preceding and following steps, resulting in six additional intermediate steps in which all three phases are active. By doubling the number of steps, current and torque will vary less over time compared with current solutions without increasing the size or changing the design of the motor.

Controlling brushless motor commutation

The present invention relates broadly to commutation control of a BLDC motor for use with, for example, a power tool. The method uses a controller to control a BLDC motor in the event of a position sensor failure. Rather than ceasing operation of the motor and indicating a fault or error message to the user, the present invention determines when the next transition should occur based on the time between past hall transitions using a timer. Thus, if one or two position sensors are no longer providing position information to the controller, the controller can determine when the transitions would be changing based on past transitions to continue controlling the motor and prevents the motor from ceasing operation.

Controlling a brushless motor

Overcurrent protection of an electrically powered, motorized device, such as a power tool, wherein the tool includes a tool housing, an output assembly, a trigger, an electrical safety device, a motor, an indicator, a controller, and a power source. The electrical safety device, for example a fuse, is disposed in series with a power connection from the power source to the controller. The controller measures current passing through the electrical safety device in time intervals when the trigger is actuated. The controller determines accumulated thermal energy passing through the electrical safety device, and compares the accumulated thermal energy to a threshold. If the accumulated thermal energy exceeds the threshold, the controller ceases or discontinues to allow power to be provided to the motor from the power source, thereby shutting off the motor. The controller may also activate the indicator to indicate a fault to the user.

Overcurrent protection for electric motor

The present invention relates to a motorized hand tool having a motor with a motor front casing adapted to resist rotation of the motor with respect to a housing of the tool, without use of extra fasteners or machining operations. The motor front casing includes first and second flanges and first and second tabs that protrude radially outwardly and that are disposed proximal to respective ends of the flanges. When the motor is installed, the tabs abut a ratchet head housing and are sandwiched between the ratchet head housing and a rib if a tool housing to resist motor rotation and ensure all forces are distributed across a whole face of the rib to minimize deformation of the rib and/or tool housing.

Tool and motor anti-rotation

A two-stage braking method for a brushless DC (BLDC) motor. The method includes control a switching array to drive the BLDC motor according to a commutation scheme to decrease a speed of the BLDC motor, allow the BLDC motor to coast, determine the speed of the BLDC motor, and actuate high side switches and/or low side switches to substantially stop rotational movement of the BLDC motor.

Method of braking a power tool

The present invention relates to switching element protection of a BLDC motor, such as used with a power tool. The present invention checks each switching element of a power stage individually for a short circuit when a trigger of the tool is actuated. Each switching element is turned ON for a period of time (such as 1-5 microseconds, for example), current flowing through the half-bridge or the full power stage is measured, and that switching element is turned OFF. When the current is greater than or equal to a threshold (such as 5 A, for example), the controller stops and indicates a fault condition. By testing each switching element in order, the controller is able to determine whether the shorted switching element is the opposite one in the half-bridge being tested.

Short circuit protection for a BLDC motor

Tool illumination device

A computer implemented method for controlling commutation of a brushless DC (BLDC) motor. The method includes controlling a switching array to drive the BLDC motor at a first commutation, receiving and monitoring power consumption signals indicating power consumption of the BLDC motor, determining whether the power consumption exceeds a first threshold value, and controlling the switching array to drive the BLDC motor at a second commutation when the power consumption exceeds the first threshold value.

An end cap for a brushless motor that dissipates heat from a controller and switching elements of the motor through fins in the end cap. The end cap can be directly or thermally coupled to the controller and switching elements to dissipate heat out through the fins.

Brushless direct current motor end cap

A printed circuit board (PCB) for motor and display control of a tool. The PCB is disposed within a housing portion of the tool substantially perpendicular to a display assembly of the tool. The PCB includes integrated switches adapted to engage corresponding buttons of the display assembly. The housing portion and display assembly including features to restrict movement of the PCB relative to the housing portion.

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Greendale, WI, United States of America

Michael T Rajzer