Accumulation conveyor with retractable sensor

摘要

A pneumatic accumulation conveyor has an anti-singulation control capable of deactivating the drive of a zone if the product sensor for that zone and substantially all of the product sensors downstream of that zone sense the presence of product in order to produce an accumulation portion with no zones actuated and is capable of activating the drive of a zone if any of the drives downstream of the associated zone are actuated in order to produce a transport portion in which all zones upstream of any actuated drive are actuated to transport product without singulation of any upstream grouped product. The accumulation conveyor is controlled by retractable product sensors positioned at particular locations along the product conveyor in order to sense the presence of product at the particular locations. Each of the product sensors includes an arm that is selectively positioned in the path of the product being conveyed by the product conveyor, a switch having an actuation member juxtaposed with the arm and a force-producing connection from a drive actuator of a downstream zone in order to move the arm from a position in the path of the product being conveyed to a retracted position. A mode control is provided for selecting one of first, second and third modes. In a first mode, the control actuates a discharge conveyor section and causes all sensors to be retracted from their sensing position to provide a slug discharge mode in order to clear out accumulated product without singulation. In a second mode, the control actuates the discharge conveyor but extends one group of sensors to a sensing position. This provides singulation between packages at the location of the sensor rollers to provide a singulation discharge mode in which gaps are drawn between packages. In a third mode, the discharge conveyor is deactuated and all sensors are allowed to be in their extended position in order to accumulate product.