The bladder inside your air shaft is going to fail. It’s just a matter of time. When it does, your production line will slow down or even come to a stop until the bladder is replaced.
Depending on your air shaft, maintenance time could vary from 10 minutes to three hours or more if you have a spare bladder on hand. A well-designed air shaft that makes repairs quick and easy could be the difference between pausing production for days and resuming operations quickly. The good news is that a proper air shaft design that makes it easy to access the bladder can help you save time and money on maintenance.
Air Shaft Design for Easy Bladder Replacement
Easy repairs and fast bladder access are crucial to efficient air shaft maintenance. A well-designed shaft makes removing the journals to access the bladder simple and quick. The type of connection that holds your journal in place will determine how easy it is to replace the bladder. There are two main ways to fit the journal to the body of the air shaft to ensure torque transmission – shrink-fitting and user-replaceable journals.
What is Shrink-fitting?
Shrink-fitting is a technique that secures the journal in place by heating up the shaft housing so you can slide in the end of the metal journal that has been cooled. Once the metal cools, it ensures a tight connection between the journal and the housing. A pin is usually inserted to solidify the connection. This old-school technique is common across the industry due to the strength of the connection and low cost. There are a few downsides to using this design, however:
- Long maintenance times
- The need for special tools like a slide hammer to remove journals
- A heat source/open flame has to be used to heat the shaft housing
Shrink-fitting can even lead some maintenance staff to ship out air shafts off-site for routine maintenance. Whether it’s due to the lack of available staff, lack of proper tools, or the inability to use an open flame source in your facility, you may have to wait on an expensive and slow third-party vendor to replace an essential part.
This scenario not only creates added costs, but also results in a loss of productivity for key lines in your facility. Even if you can do the job onsite, removing a shrink-fit journal is a two-man operation that can take hours while also exacting a physical toll on your team.
Current Shaft Technology
Well-designed, modern lug-style shafts eliminate the issues that occur with shrink fit journals. The shafts are designed with user-replaceable journals that make it simple and fast to access a damaged bladder. Current technology shafts typically use high-strength, flathead fasteners and a tight tolerance fit to secure the journal to the housing of the air shaft. Unlike shrink-fit journals, these journals can be repaired quickly without the need for specialty tools or a heat source. By simply unscrewing the fasteners, you will be able to access and replace the damaged bladder.
Simple, quick access will make your staff grateful when it’s time to replace a bladder. In addition to easy journal removal and bladder access, these shafts are designed to:
- Improve workflow with better ergonomics
- Decrease machine down time
- Maintain a close tolerance fit to the core
- Maintain a strong grip on the core
- Not need lug springs
With less chance of damaging the shaft body and no need for specialty tools, you can rest assured that your machine can get back to full capacity quickly.
Air Shaft Bladder Selection
Air shaft bladders are rubber tubes within the shaft housing of the unit that inflate and grip the core to transmit torque so that your machine operates properly. Since the air shaft’s lugs make contact with the bladder while your machine runs, you will experience routine wear on the unit based on how aggressively you run the application.
To maximize machine uptime, you need to be confident that the bladder inside of your lug shaft is both durable and easy to replace. The material of the bladder inside the air shaft and the ease of journal removal are equally crucial to keeping your machine up and running.
Bladder Material
You want to make sure that you maximize your bladder life. Based on how aggressive the application is, you should keep bladder material in mind when determining which air shafts are right for you.
Lug shaft bladders are traditionally made of black rubber which tends to wear down relatively easily and struggles to retract once expanded. Due to the expanding nature of the bladder, this material can develop memory that makes it hard for the lugs to fall back below the shaft housing. Old-style lug shafts solve this problem by using lug springs to pull the lugs below the housing. When the lug springs break, they will eventually puncture the bladder.
Polyprene bladders are designed to combat this issue as the material is more durable and does not experience the same memory problem that black rubber does. Since polyprene bladders are designed like steel-belted radial tires with an outer wrapping layer, the bladder always retracts back to its original shape. Lug shafts using this bladder materials don’t need to have springs to help the lugs retract. You get both a more durable bladder material that doesn’t develop memory and a shaft design that doesn’t need lug springs. This bladder material truly maximizes your line’s uptime while minimizing maintenance time.
Being able to replace the bladder in your lug shaft can be difficult, but it doesn’t have to be. To minimize machine downtime, you want a bladder that is easy to replace, durable, and does not develop memory. Consider choosing a lug shaft that requires pain-free, infrequent bladder replacements.
Ensure Your Machines Run Smoothly with Double E
Double E revolutionized shaft making more than 35 years ago with the introduction of the Dura-Light® Composite Core Shaft. Since then, we have continued to innovate, delivering exceptional quality shafts and winding accessories that limit downtime and maximize productivity.
For a trusted manufacturer and supplier of core shafts, shaft handlers, and shaft accessories, Double E is the only choice. Contact us today to learn how Double E can improve your business and keep your machines up and running smoothly.