PORTINNRETNING.

摘要

A gate assembly comprises an angularly displaceable support structure disposed along a path to be gated and a gate member is pivotally mounted on the support structure for pivotal raising and lowering movement between a vertical, nonworking position wherein the gate member does not extend across the path and a horizontal, working position wherein the gate member extends across and blocks the path. The gate member is also mounted for linear movement towards and away from the support structure to enable extremely accurate positioning of the gate member. An oscillatory fluid motor effects angular displacement of the support structure and a set of reciprocatory fluid motors effect raising and lowering of the gate member as well as movement of the gate member towards and away from the support structure. A fluid control circuit automatically actuates the various fluid motors in a predetermined sequence.