Gate operator and method using automatic limit adjustment

Abstract

A gate operator for moving a gate between two fixed end positions such as a gate opened position and a gate closed position and minimizing the possibility of impact with a fixed structure at either of these end positions. The operator relies upon measuring the number of electrical pulses or so-called counts representative of a distance between the two fixed end positions. The gate operator includes a controller in which the number of counts are measured between movement from an open position to a closed position, or a closed position to an open position, and the count is automatically readjusted to eliminate any hard contact of the gate at a fixed closed or open position. In one of the important embodiments of the invention, the gate operator utilizes a controlled coasting system. In this case, the gate is driven from one end position toward the other end position by a motor and the motor is de-energized by a preselected number of counts at a coasting position in advance of the end position toward which the gate is moving. If the gate still strikes the end position or overdrives the end position, the operator automatically compensates so that the gate automatically reaches the end position to which the gate is moving and automatically stops.