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Core Adapters

Core adapters are useful in applications where you want to unwind or rewind your material with a larger core diameter than you normally run. For example, your process may normally use 3" inside diameter cores. It is possible that you may, on occasion, want to utilize 6" inside diameter cores. Again, this is just an example of common core sizes; other core sizes are possible.

So, in this example, if your machine is currently outfitted with 3" air shafts, core adapters may be a cost effective and relatively simple answer to being able to run 6" cores. Core adapters come in many designs, each with their own unique benefits.

Air chuck type core adapters are standard length pneumatically operated chucks. These chucks may be relatively short when compared to your web width. If this is the case, two chucks, one mounted to each end of the of the air shaft support to support each end of the long core may be utilized. These chucks will be inflated independently from the air shaft support. Typically, these chucks will be bored to fit the deflated air shaft support. They will include a locking mechanism to lock them to the air shaft. Alternately, their design may be to inflate the air shaft support to lock them in place. An independent, mechanical locking mechanism is the best option, it will supply more torque than inflating the air shaft to lock the chucks in place.

Tandem air chuck type use the same air chucks as described above. However, the chucks described above must be inflated independently of each other. So, two chucks means inflating twice for each roll change. Tandem air chuck design joins the two air chucks through length of flexible plastic tubing. That means either chuck could be inflated and by doing so, the opposite chuck will inflate with the pneumatic pressure supplied through the plastic tubing. One inflate / deflate operation per roll change may or may not be important to your operation. Depending on how time sensitive roll changes may be.

Mechanical chuck type core adapters operate similar to the pneumatic type with the same type options for locking to the air shaft support. However, instead of being inflated to engage the core they mechanically lock to the core. The mechanical locking operation comes in many designs. Some automatically lock to the core with core rotation, while others require tools.

End plugs or dummy chucks may be used in conjunction with one pneumatic or mechanical chuck. The end plug is a metal cone shaped device that has a flat land that the core sits on when it is fully inserted into the core. Typically they include a core stop flange to allow them only to be inserted so far into the core. The end plug does not supply any torque to the core and has no function in locking the core to the air shaft support. The torque function will be supplied by the air chuck or mechanical chuck mounted on the opposite side of the core. The disadvantage to using an end plug is that the torque delivered to the core is half of the amount of torque that will be supplied by two air or mechanical chucks.

Air shaft type core adapters are custom length core adapters that are manufactured to approximately the same length as your smaller diameter air shaft support. This core adapter will be independently inflated from the smaller diameter air shaft support. Typically, the core adapter will be bored to fit the deflated air shaft support. These will include a locking mechanism to lock them to the air shaft. This type of core adapter is the most costly. However; they are the best option, considering that this option supplies the most amount of torque to the core and is the easiest for setup and operation. This option excels in applications where web widths vary often.

Core cones again, with similar options for locking to the air shaft support, may be used on each end of the core. These are not the same as end plugs. Core cones are cone shaped metal with serrates. The serrated cone digs into the core ends to deliver torque to the core.

Spacer type core adapters are a very inexpensive option. This type of core adapter is manufactured of multiple sections that will move and grow and shrink in diameter by inflating and deflating the air shaft support. Be wary of this type of core adapter, while the initial cost is low, they deliver the least amount of torque to your core, which can lead to core slippage. Also, they can be difficult to operate and position properly.

Core adapters, properly applied, can be a very cost effective, productive answer for the difficult task of running with abnormal core sizes for your operation.


Written by:
Jeff Damour, Converter Accessory Corporation

**DISCLAIMER - A great deal of time has been invested in the development of our weekly tech tips. To the best of our knowledge, they are accurate. It is up to the user to verify all results.


Converter Accessory Corporation
201 Alpha Road
PO Box 188
Wind Gap PA 18091-0188

Phone (800) 433-2413 -(610) 863-6008
Fax (800) 709-1007 - 610) 863-7818

What is Web Handling?
Web Handling is the science, engineering and equipment necessary to successfully transport a continuous flexible material through various processes without defect. Enhancing Web Handling with proper equipment will ensure materials are processed at their maximum efficiency, allowing the process to generate maximum profits.

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