US Patent 9695605 Battery powered concrete vibrator

A battery powered concrete vibrator is provided with a vibration head; a brushless DC motor disposed in the vibration head; a drive shaft disposed in the vibration head, rotatably disposed through the brushless DC motor, and operatively driven by the brushless DC motor, the drive shaft including a lengthwise groove on an outer surface, thereby rendering the drive shaft unbalanced; and a groove-shaped vibration member put on the drive shaft. The drive shaft can impart rotation to the vibration member.