Abstract: A 90.degree. gate opener (20) includes a screw (22), and a nut (30) which travels along screw (22) as the screw (22) is turned by a motor (46). One end of a main arm 32 is pivotally connected to nut (30) so that it also travels along screw (22). Screw (22) is dispositioned a predetermined distance (D) behind a pivot (38) which slidably receives main arm (32). As screw (22) is turned, main arm (32) rotates approximately 90.degree. about pivot (38), and in so doing also slides through pivot (38). As a result of the increased mechanical advantage of the gate opener, a motor of smaller horsepower rating may be utilized. Gate opener (20) may be used in either horizontal or vertical applications.

Abstract: A gate opening apparatus which utilizes a horizontably swingable arm assembly which is to be operated electrically to effect movement of a gate between a closed position and an open position. The arm assembly is mounted through a latching mechanism to the motor mechanism of the gate opening apparatus. This latching mechanism can be manually released which will permit the arm assembly to pivot through a vertical plane so as to provide for manual movement of the gate between the open and closed position during instances when electrical power is not available to operate the gate opening apparatus.

Abstract: An opening and closing mechanism for a gate which utilizes an electric motor operating through a electromagnetic clutch. The clutch is to be operated at a significantly increased voltage during the initial period of starting movement of the gate. When the gate is rolling, the voltage through the clutch is significantly decreased to a substantially lower level. During this lower level of movement even a minor amount of resistance applied to the gate will cause the gate to stop thereby avoiding injury to animals (including people) and damage to devices such as automobiles. The gate opening and closing mechanism also includes a separate direct drive mechanism which by-passes the clutch when the gate is in the completely open or the completely closed position. This separate direct drive mechanism functions as a positive lock maintaining the gate in its established completely open or completely closed position when the gate is in either of these positions.