Abstract: An electric motor (10,110,210) comprises a TRIAC (16, 116, 216) for controlling the application power to the motor and a switch (18,118,215a) for controlled cut-off of the power supply. Upon operation of a switch (15b, 115B, 215B) for short-circuiting of motor from a power supply (13, 14; 113,114; 213,214) armature the power is supported to the field windings (12,112,212) with at least one predetermined braking voltage. Upon exhaustion of a braking period, the switch mechanism operates to cut off power completely from the motor.
Abstract: An electric motor (10, 110, 210) is coupled to a TRIAC (16, 116, 216) for controlling the application of power to the motor from a power supply (13, 14; 113, 114; 213, 214) and a switch (18, 118, 215a) for controlled cut-off of the power supply. Upon operation of a switch (15b, 115b, 215b) for short-circuiting an armature (11, 111, 211) of the motor, power is supplied to field windings (12, 112, 212,) of the motor with at least one predetermined braking voltage. A braking period can be established following short-circuiting of the motor by (1) a prescribed delay, (2) comparing the changing voltage level across the TRIAC (16, 116) and cutting the power off when the voltage level rises to a prescribed level, or (3) monitoring the decreasing speed of the motor to cut off the power when the speed decreases below a prescribed level.
Abstract: A hand held router (2) includes a rotatable member (22) having screwthread engagement with the housing (4) of the router (2). Rotation of the rotatable member (22) causes adjustment of the depth of cut of the router bit (18) protruding through the rotatable member (22). A releasable detent means (30) engages with latching members (28) in the rotatable member (22) thereby to enable locking of the depth of cut mechanism.
Abstract: An abrasive sheet 1 for a sanding or polishing machine, comprising a body portion 3 and a tip portion 5 providing a working point 11, the tip portion 5 being defined by a weakened region 7 between the body portion 3 and the tip portion 5, wherein the tip portion 5 can be separated from the body portion 3, turned through an angle (FIG. 2) and re-positioned adjacent the body portion 3 to change the working point 11. As a result, an iron-shaped abrasive sheet, for example, can be provided with a plurality of working points 11. The sheet can, therefore, be used for longer periods before it is worn out.
Type:
Grant
Filed:
March 6, 1997
Date of Patent:
April 4, 2000
Assignee:
Black & Decker Inc.
Inventors:
Michael Martin, Colin Pugh, Eric Cockburn
Abstract: The present invention is directed to an on/off switch for a flashlight having a reflector secured against axial motion. The reflector has a central opening. The flashlight includes a bulb with a base having an outer cylindrical electrical terminal. The bulb extends through the central opening of the reflector. The switch includes a bulb holder, with the bulb secured in and moving with the bulb holder. The switch also includes an electrical contact disposed in the flashlight so as to be adjacent and biased away from the cylindrical electrical terminal of the bulb. The switch also includes a ring rotatably disposed in the flashlight. The ring is mechanically linked to the bulb holder and includes an element disposed adjacent the electrical contact.
Type:
Grant
Filed:
August 9, 1996
Date of Patent:
April 4, 2000
Assignee:
Black & Decker Inc.
Inventors:
Leo K. F. Cheng, Eddie Y. H. Lo, Victer Au-Yeung Tin Shun, Roger Q. Smith