The frame of the metal slates conveyors is constructed of thick electrowelded tubes with transverse frames with constant pitch, in bolted modules to facilitate assembly with interchangeable runners for the chains, height-adjustable legs, side and lower protective chain housing. The large motor is mounted with a shaft flange for easy maintenance, while the brakemotor prevents the material on the conveyor from slipping by inertia when the conveyor stops. The pre-stretched drivechain is equipped with hardened gauge wheels, bushing and pivot, while the holding flaps prevent the material from exiting the slider bed. The side walls are designed with a modular system so they can be raised even after first positioning to make the conveyor versatile for product changes. The thick metal slates can be used for heavy loads and for long durations. The side hatches for chain maintenance and lubrication facilitate ordinary and extraordinary maintenance.