When it comes to "Rigid Couplings"... this is about as rigid as it gets. The "Flange Coupling" is very simple to describe. It is made up of two hubs (that fit on the equipment shafts), with those hubs being machined with a multi-bolt flange on one end. When the equipment is "coupled", the flanges are bolted together and basically become ONE LARGE MASS! How simple can it get?
While we've described the "Flange Coupling" as being a RIGID coupling, there are hybrid designs that use "rubber" (or some other flexible/soft material), as a bushing, normally inside the bolt holes of one of the flanges. The application of this flexible material allows the "Flange Coupling" to withstand some misalignment and afford a small degree of flexibility and vibration damping to an otherwise very rigid device.
The following description and drawings are taken from the website: www.extrudesign.com. I thought it was rather straight forward and I like the description and drawings of the types of flange hole patterns available from various manufacturers, and for specific reasons.
A coupling having two separate flange hubs with the keyed fit to the individual shaft. These two flanges will be joined together with the bolted pattern. On one flange there will be an outward projecting machined area called pilot or spigot, and on the other flange there will be a corresponding recess machined to make the perfect alignment for both flanges.
The inherent design of the "Flange Coupling" will help maintain shaft alignment and is also capable of handling heavy loads. This feature adapts it for use on large shafts and large, heavy equipment.
There are three different types of flange couplings.
- Unprotected type flange coupling (The bolts and nuts are totally exposed)
- Protected type flange coupling (The bolts and nuts are recessed in the flanges)
- Marine type flange coupling (Flanges are an integral part of the shaft)
A "Flange Coupling" transmits the highest values of load, as any shaft coupling design on the market. The concept of torque transmission may be described differently by various manufacturers, while the method of attachment and connection will remain basically the same among the. One manufacturer will tell you that it is the "clamping force" of the bolts, causing high friction between the faces of the flanges, is what actually transmit the power, while another will say that the mechanical strength of the bolts is actually the method of power transmission. In either case, this type of shaft coupling transmits 100% of the power from the driver to the driven equipment, with no loss due to flexing of components. And while this is all true, ONE thing that stands out as a "con", is that with zero ability to withstand angular and/or parallel misalignment, equipment alignment is VERY critical. We definitely recommend "Laser Alignment" or expert dial indicator alignment during the installation process.
"Flange Couplings" can be purchased with a "pilot bore", where you can have the hubs bored and keyed as necessary; or you can have them "bored to size" to minimize any added expense and time after purchase. Lastly, the hubs can be purchased as a "bushed" type of bore, where you can purchase the proper size "taper-lock" type bushing to suit the application. This last type allows for use of the coupling on a different machine... down the road.
So when your ready, give the sales folks at A.R.&E. a call and they can assist you in the proper selection of a "Flange Coupling", if that's best, and supply it for you when you're ready to purchase.