Transmission for power tool with variable speed ratio

• Main Authors: ZHANG QIANG J, MURTHY SANKARSHAN, MATTHEWS BEVERLY
• Format: Patent
• Language: English
• Published: 18.11.2014
• Subjects: BLASTING; BORING; COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDEDFOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOTPARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOTOTHERWISE PROVIDED FOR; ENGINEERING ELEMENTS AND UNITS; GEARING; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HAND TOOLS; HEATING; LIGHTING; MACHINE TOOLS; MANIPULATORS; MECHANICAL ENGINEERING; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; PORTABLE POWER-DRIVEN TOOLS; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; THERMAL INSULATION IN GENERAL; TRANSPORTING; TURNING; WEAPONS

A power tool includes a housing, a motor contained in the housing, an output shaft extending proximate a front of the housing, an end effector coupled to the output shaft and configured to hold an accessory; and a transmission disposed in the housing between the motor and the output shaft. The transmission includes a variable ratio gear set configured to transmit power from the motor to the output shaft at a substantially variable speed ratio. The transmission may further include a constant ratio gear set configured to transmit power from the motor at a substantially constant speed ratio. The transmission may be automatically or manually shiftable between a first mode where it transmits power through the constant speed ratio gear set and a second mode where it transmits power through the variable speed ratio gear set.