Pallet load sensing system

Abstract

The present invention relates to a system for positioning pallets to be wrapped with a pallet stretch wrap machine and to adjust operation of the wrap machine according to measurements obtained from sensors, identify the relative size of the pallet load to be wrapped in stretch film, detect misalignment of the load and thereby control activation of the wrap sequence and the speed of the film applied.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to U.S. Provisional Patent Application No. 61 / 890,404, filed on Oct. 14, 2013, the content of which is fully incorporated herein by reference.BACKGROUND[0002]Pallets of various goods are stretch-wrapped for secure transportation. Automated stretch-wrap machines are commonly used for stretch wrapping a palletized load, which include conveyor-type systems in which pallets are loaded and transported on a conveyer, and manual stretch wrap systems in which pallets are floor-loaded using a forklift or pallet jack, positioned at a wrapping machine by an operator, and then again transported by an operator after the wrapping operation. Floor-loaded stretch wrapping systems may comprise a single arm for wrapping a single pallet, or may be multi-headed for wrapping multiple pallets simultaneously. In the case of multi-head assemblies, i.e., wrapping assemblies with multiple wrapping stations, when a pallet is incorrec...

AI Technical Summary

Benefits of technology

The invention provides a system that helps position pallets for wrapping with a pallet stretch wrap machine and controls the speed of the wrapping sequence for optimal results. The system uses sensors to measure the load on the pallet and checks if it is in the correct position for wrapping. It ensures that the pallet is in proper position for wrapping and takes immediate action if it detects an incorrect position. The system also measures the distance between the stretch wrap machine and the outer surface of the pallet to determine how much film will be needed. The use of the invention offers several benefits such as the ability to use thinner films, less film breaks, smoother unwind of film, and the ability to be provided with a film cost per pallet.

Problems solved by technology

In some cases, the wrapping head of each working station will finish wrapping before the incorrectly positioned pallets can be adjusted, which results in additional operator efforts in the unloading of wrapped pallets and loading of new pallets.

Further, often the pallets are positioned at the wrapping assembly such that, when one of the loads is not in proper orientation and the wrap sequence is thereby not activated or is shut down at that station, it is not possible for an operator to reach the problem due to the other pallet loads being in the way.

This results in a condition in which a skewed or misaligned load in a station is positioned such that there are varying distances between the load and the prestretch device as the film prestretch device rotates around the pallet.

This causes stress on the film at the prestretch device and potential breakage of the film, resulting in failure of the wrapping operation and down-time due to the need for an operator to correct the problem.

Further, challenges exist with making such speed adjustments, which may require mechanically altering the film drive mechanism, such as altering a gear ratio at the motor of a prestretch head device.

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