How to Get the Most from Your Mechanical Core Chucks
Mechanical core chucks are an excellent choice for holding the core of a roll of material. They work equally well for unwind and rewind applications. Mechanical core chucks operate mechanically without the need for compressed air (no inflating or deflating, as with air operated chucks). Oftentimes, they can deliver higher levels of torque than air operated core chucks. Mechanical core chucks can be more difficult and take more time to load and unload from the cores they support. Here are a couple of tips to get the most from your mechanical core chucks.
Consider how the mechanical core chucks are operated. Many mechanical core chucks lock "automatically" with the rotation of the core. If that is the case, then maintaining web tension is critical. It is web tension and the torque associated with it that actuates the core locking mechanism with this type of mechanical core chuck. If your web tension varies greatly or goes slack (throws a loop), as with some intermittent feed applications, for example, then the mechanical core chuck may lose grip of the core. Air chucks may be a better choice if your operation doesn't maintain tension under normal running conditions.
Do you need bi-directional locking? Some mechanical core chucks offer locking in one core rotation direction only and unlock in the opposite core rotation. Some mechanical core chucks will lock with either rotational direction and unlock in the middle of the travel between the two lock positions.
Maintenance can be an issue. Springs, gears and other parts will wear over time. Keep up with the maintenance of your mechanical core chucks. When considering new mechanical core chucks, remember simpler design means less maintenance and less components to fail.
Core material can be an issue. Mechanical core chucks work well with standard cardboard cores but may have trouble properly engaging plastic or metal cores.
Make sure mechanical core chucks are properly specified to handle your roll weight and tension (torque) requirements.
Cores often vary inside diameter (I.D.) sizes. Be sure your mechanical core chuck expansion range; unlocked position to locked position will accommodate your core I.D. variance.
Are the mechanical core chucks being supplied with a thru bore to fit a thru shaft? If so, consider how the mechanical core chuck clamps to the thru shaft. Some designs use simple set screw, directly contacting the thru shaft. Better designs use other methods (like split bushing) of locking to the thru shaft for more positive locking without the possibility of damaging the thru shaft with set screw contact.
Finally, if your not the person who runs the machine, talk to the person who does. Discover their concerns when it comes to making easy, fast roll changes. Make sure the mechanical chuck you use is the best solution for the people who run the machine and make roll changes.