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. 10, 1985
Filed:
May. 24, 1983
Friedrich Hornung, Stuttgart, DE;
Fritz Schadlich, Leinfelden-Echterdingen, DE;
Robert Bosch, GmbH, Stuttgart, DE;
Abstract
To provide for, selectively, control of the speed of a tool, such as a drill or boring tool coupled to an electric drill or boring machine motor, independently of the setting of a multi-speed transmission, speed of the tool is sensed by a contactless transducer (4, 7), one part of which is coupled to the chuck (1, 2) and the other to the housing (H) of the tool, to provide speed signals which incorporate the transmission ratio of the gear (G, 66). Speed control, for example under a command signal (40; 50), then will control the actual speed, regardless of the transmission setting, with the torque deliverable by the motor being controlled by the selected gear. The diameter of the drill or other tool bit is sensed also by the transducer, if coupled to the chuck jaws, to vary the output signal from the transducer as a function of chuck jaw diameter. The output signal can be selectively analyzed for frequency in a frequency evaluation stage (35), and for amplitude in an amplitude evaluation stage (34), the speed and chuck jaw spacing signals can be separated (FIG. 8) from a combined speed - chuck jaw spacing signal obtained, to provide for control of the motor as a function of material being worked on (40; A-D), of accessories (40) to associate output speed with materials and drill diameter in accordance with selected functions, or only of speed, for example for operating accessories such as screwdrivers, sanding disks, or the like.