The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 29, 1981
Filed:
Feb. 14, 1980
Giuseppe Cuneo, Calolziocorte, IT;
Black & Decker Inc., Newark, DE (US);
Abstract
A speed control device for portable power tools having particular applicability to electric drills. The speed control device is adapted to automatically adjust the speed of the motor in accordance with changes in the diameter of the tool bit used. The device includes a sensor that senses the opening and closing of the jaws of the chuck. The sensor is mechanically coupled to a potentiometer circuit whose output signal is varied in accordance with movement of the sensor. The output signal of the potentiometer circuit controls the firing angle of a thyristor 34, which in turn controls the current supplied to the motor. In addition, the preferred embodiment includes a speed select switch which is connected to the potentiometer circuit to set the appropriate speed range for the motor, given the particular type of work material.