Overhead cranes: How a company changed focus on operator safety
30/08/2011 - The company in question is a leading motor components parts company. Ron Mileham
They struggled for years to overcome some product handling issues. Each fix was a make do and mend, designed to solve the problem for the least amount of money.
The company was increasingly becoming known to WorkSafe due to a number of issues surrounding the safety of operatives. One of the major issues was that of operators having to lift plastic crates full of parts, from the conveyor lines onto pallets, building up a stack ready for removal by walkie stacker, then transported to an area away from the welding machines, and into a holding area, where they would be collected by a forklift for consolidation and storage elsewhere.
The second major issue was in the order packing area of another plant, where crates of parts were retrieved from pallet racking, and again used to build up a pallet load ready for shipping to clients.
The company was bought out by an overseas international in a similar line of business. With increasing pressure from WorkSafe and the parent company wishing to set a good example of a safe working environment, the Safety Officer and the Chief Engineer were set a task and offered funding in order to resolve these long running issues.
It was identified that a single operator might shift as much as two tonnes in weight over the course of a shift, albeit in 15 Kg increments (the weight of the loaded crate).
I was asked to liaise with the two company representatives to determine if there was a simple, effective and cost efficient solution to their problems.
The task involved a complete change of mindset from the low cost semi-fixes of the past, to a complete fix based upon realistic goals and with funding to match.
I determined that the only solution was to fit overhead, two axes gantry cranes with hoists. This gave the operator an area in which to work, using only the hoist to raise, move and lower the plastic crates, so no manual labour would be involved.
The first requirement was to examine the plastic crates, in order to determine common denominators at both plants. An end effector (pick up device) was required, to be used one-handed, as the other hand was on the hoist control pendant.
We fabricated several options, and as each was tested and rejected, the Engineer at the plant took time to discuss the preferred end effector design with the individual operators in order to ensure that they ‘owned’ it.
Having decided upon a crate pick up device, the next step was to decide which type of crane would be best suited to each plant. The manufacturing plant required cantilever gantry cranes where the aisle was covered, but where columns were on one side only, as there was no room for columns on the other.
The second plant went for the traditional style with columns on each side, and the area between the columns was available to the hoist. Prior to the crane, the crates were removed from the pallet racking. In the new model, the racking was removed. A yellow line was painted on the floor beyond which only the operator’s walkie stacker could roam. On the other side would be the forklift.
Pallets were laid out with different product on each of both sides of a central aisle. In the centre aisle was placed a row of empty pallets. The operators used the hoist to pick up crates from any of the stock pallets in order to build up orders in the middle aisle. When completed, the pallet would be taken to the yellow line for the forklift to pick up and store or ship.
Problems solved. WorkSafe are happy. The company has saved on injuries and claims. The parent company is showing it is acting responsibly. The Engineer and Safety Officer received commendations for their work. The operators are healthier and safer.