Patent ID: 8528236

Claim:
A device for creating a trench in a ground surface, the device comprising: a frame having a handle, an axle and a platform; a wheel mounted to the axle to at least partially support the frame for movement on the ground surface; a motor mounted to the platform, the motor configured to rotate a drive shaft, the drive shaft including a proximal end portion, a distal end portion and a mounting flange located near the distal end portion; a primary blade removably mountable to the drive shaft near the distal end portion of the drive shaft, the primary blade having a primary hub and at least three primary tines extending radially from the primary hub, the primary blade having a first radius measured from a geometric center of the primary hub to a free end of any one of the at least three primary tines; a secondary blade removably mountable to the primary hub, the secondary blade having a secondary hub and at least three secondary tines extending radially from the secondary hub, the secondary blade having a second radius measured from a geometric center of the secondary hub to a free end of any one of the at least three secondary tines, the first radius being greater than the second radius; and a blade guard mounted to the platform and generally covering the primary and secondary blades in an assembled configuration.