Abstract: An easy-detachable grinding device for a cement walk-behind trowel machine comprises a plurality of installing units arranged on a seat which is installed with the central disk and the outer rotary disks. In use, it is only needed to buckle the installing units to the grinding knives of a power source of a cement walk-behind trowel machine so that the central disk and the outer rotary disks are assembled to the cement walk behind trowel machine. The original grinding knives are unnecessary to be detached from the cement walk behind trowel machine. Furthermore the grinding device can be detached easily as it is not used, while the original used grinding knives can be used again. No more vehicle is needed. Outer rotary disks are arranged on the periphery of the central disk so as to have a large grinding area.

Abstract: A cement surface grinding device includes a central disk which is extended upwards with a central shaft; the central disk being rotary with respect to the central shaft; at least one outer rotary disk arranged around the central disk; a bottom of the outer rotary disk being installed with a grinding sheet; and a rotary frame arranged above the central disk and the at least one outer rotary disk; the rotary frame including a connecting frame and a plurality of connecting rods; an upper side of the central shaft being connected to a central hole of a seat and the seat being connected to a lower side of the connecting frame; each outer rotary disk being formed with an outer belt wheel and the central disk being formed with a connecting element; and a belt winding around the connecting element and the outer belt wheel.