Anatomy of a Pit Cover
September 27, 2019
There are a lot of different options when it comes to pit safety covers. Some are as simple as what material is used, whether it is net, aluminum, or stainless steel. Other options get more complicated, such as what type of drive do you need to automate your pit safety cover and the best way to stay in compliance with OSHA standard 191.21.
The best way to navigate all these options is to know the ins and outs of an automated pit cover, and the benefits and limitations of those options. All of our pit cover designs are custom and tailored for our customers’ specific applications. But, different materials and cover varieties have varying limitations.
Material choices are important, especially when you have a custom application. You need to consider how the unit will be used before choosing a material. Certain applications or conditions require varying material options and sometimes even specific coatings. Corrosion limitations mean that some chemicals are too aggressive for aluminum so stainless steel would have to be used. On the other hand, if you’re dealing with ranging temperatures, stainless steel allows for temperatures up to 200°F, while aluminum only starts losing some of its strength at 350°F. Most aluminum covers perform just fine in chip, oil, and coolant applications, but if you’re dealing with the more challenging stuff - like swarf and sand - stainless steel is a better option.
At the end of the day, it’s all about your application. Picking the right tool for the right job, or in this case, the right safety device for the application.
The list of options is long and there’s definitely a need to evaluate all aspects of your application. That’s why Hennig’s pit safety covers are custom-made to your specifications, because every application is unique.
CUSTOM PROTECTION FOR OPEN PITS, EXPOSED WAYS, LINEAR GUIDES, AND TANKS OF ALL SIZES.
➀ MOUNTING OPTIONS
There are a number of mounting options to make sure that your automatic pit cover fits your application.
Based on how you’ll be using your pit safety cover, you can mount it above or below the cover surface, on just about any surface that is parallel or perpendicular to the opening that you’re covering.
Beyond that, your mounting options are almost limitless, and can be adapted to fit your application.
➁ COVER MATERIAL OPTIONS
*Available as a walk-on cover
• Aluminum profiles w/ polyurethane hinges
• When rolled out, creates a flush surface (ideal for wipers)
• Resistant to high temperatures
• Resistant to corrosion
• Unsupported span limit: up to 1500mm
AGS (mini, I*, II*)
• Anodized aluminum profiles & hinges
• High strain resistance even in long lengths
• Walk-on versions available
• Unsupported span limit:
AGS mini up to 1500mm
AGS I up to 3000mm (Walk-On up to 1100mm)
AGS II 4000mm (Walk-On up to 2000mm)
• Durable, corrosion-resistant stainless steel sheets
• Withstands high ambient temperatures
• Can be assembled in sections for easy replacement of damaged areas
• Completely resistant to penetration of contaminants
• Walk-on versions available using extruded aluminum tubing for support. The supporting profiles increase or decrease in size and pitch to allow for more or less load.
➂ CONTROLS OPTIONS
• Hennig’s pit safety covers come in a broad array of options, with varying features to match your specific need. The units can be designed for compatibility with anything from PLC to VFD to push-to-move controls. If your application calls for it, we can even provide a unit with multiple position automatic extension/retraction with edge collision detection.
• Controls are supplied by the customer
➃ ACTUATION OPTIONS
• Electric drives offer the ability to extend and retract the cover directly (via a sprocket drive) or indirectly (via a chain drive). Electric drives are best used in applications that are not directly tied to other automation equipment, like a machine tool.
• Cover driven by existing component, i.e., machine table.
• Can be combined with an air motor or spring motor to keep tension on the cover while being actuated
➄ CANISTER DESIGN
• Available in stainless steel, mild steel, or aluminum
• Canister design can be customized to suit your application
➅ GUIDE SYSTEM OPTIONS
• Guide systems allow for smooth, even movement of the cover along the rails
• Guide systems are chosen based on the application
• Light curtains
• Optical perimeter fencing
• Laser sensors
• Pressure pads
• Guard rails
• Leading edge sensors
• Limit switches
• Auto shops
• Water treatment plants
• Open pits
• Large machine tools with exposed ways and pits
• Machine enclosures w/ large openings in the floor or walls