Automatic package wrapping equipment is used in many of today's shipping departments. Unfortunately the equipment is often inadequately guarded, leaving employees and passersby open to the threat of injury.
When coupled with the high speed of the wrapper and the movement of large, heavy loads into and out of the wrapper as well as into and out of loading and unloading stations, inadequately guarded equipment is an industrial accident waiting to happen. Add any number of custom wrapping stations to the equation, and we are faced with a significant safety challenge (how many pinch points do you count?).
One STI customer had such an application. Not only did the wrapping machine pose a hazard, but the back and forth movement of the loading and unloading stations created another. Like many plants with similar installations, the equipment was "protected" by nothing more than an inadequately placed barrier guard and a warning sign or two.
The key to addressing the safety issues in such applications is to identify the application challenges, and then outline a workable safety solution to meet the criteria. Following are some of the challenges faced in this and similar applications:
- Employees need to be able to get into and out of the area easily;
- No new hazards can be created;
- The solution has to be standardized to allow easy integration into other areas of the plant, and into various manufacturers' equipment;
- The solution has to be easy to wire and retrofit on existing equipment;
- The solution cannot be cost prohibitive;
- The solution must meet Risk Category 3 requirements.
STI Automation Safety Partners (ASPs) provided a solution that not only meets the customer's needs, but that is also easily transferable to many of the customer's other installations.
The Solution
- STI safety mats are installed under the load/unload table to keep the table from moving if someone is standing on it.
- An STI safety light curtain is installed across the point of entry to protect against the machine moving while someone is in the hazardous area.
- Two ER6019 safety rope pulls are installed around the wrapper, and yellow plastic warning flags are strung between the two safety ropes. These combine to form an effective visual safety barrier with emergency stop capability at all points where a person might become entangled. The rope pull switches are wired through a safety monitoring relay to ensure the safety circuit meets the required reliability levels.
- Safety relay outputs are wired into the emergency stop circuit of the equipment.
This solution from STI keeps costs to a minimum, permits ease of installation, and allows the same or a similar solution to be applied to other wrappers in the plant by addressing specific application challenges and utilizing standard safety products.
