Robust inductive sensors help with the heavy lifting

An affordable solution was required to unload bulk cargo from a shipping container and so an attachment for a forklift truck was developed by a material handling company. The attachment uses Contrinex’s robust 700 Series inductive sensors to detect the position of the forks.

Shipping containers offer a low-cost way of moving goods and so to use them for transporting bulk cargo such as wood chips and biomass, a manufacturer of material handling systems developed an innovative unloading system for a forklift truck to tip the contents out of the top of the container.

The forklift attachment has two sets of forks, a lower pair which support the weight of the container as it is unloaded from a freight wagon or truck and another pair mounted vertically above the lower pair which lifts the container’s lid.

During emptying, the upper forks lift the lid a short distance before tilting it vertically, leaving the top of the container completely unobstructed. Once an inductive sensor has detected the lid is fully open, the lower forks then rotate about a horizontal axis, tilting the container end-over-end and tipping the contents out.

The aim to eliminate the cost of specialist handling equipment requires a solution that is as capable and reliable as the specialist machinery. Therefore, as the sensor is a key element of the system, it must be robust and reliable. An extended sensing distance is also desirable to be able to mount the sensor as far away as possible from the risk of mechanical damage.

Contrinex’s 700 Series inductive sensors are robust, reliable and offer extended sensing distances. The body of the M30-diameter sensor is machined from a single piece of stainless steel and its unique resistance to damage from impact, abrasion and vibration makes it ideal for this mechanically demanding environment. A 20mm sensing distance enables it to be mounted away from the forks it is sensing, eliminating any possibility of damage from accidental collision with the forks.

A metal bracket is mounted externally on the actuating mechanism for the upper forks. The embeddable sensor is not influenced by the large amount of metal surrounding it and detects the position of the actuating arm as it drives the fork into the vertical position. The one-piece, AISI 303/V2A stainless-steel housing and sensing face are corrosion-resistant and impervious to water ingress, being IP68 and IP69K-rated.

The sensor connects to the forklift’s lower-fork tilt-control systems via a flexible PUR-sheathed cable. A sealed cable entry ensures fit-and-forget capability during extended periods of operation in an outdoor environment.

The 700 Series inductive sensors detects the vertical position of the forklift’s upper forks effectively and repeatably, ensuring the safe, reliable operation of the unloading system. Contrinex inductive sensors deliver a cost-effective solution that meets the customer’s requirements for extreme robustness and extended sensing distance.