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FASTENING/JOINING

Getting a (GENTLE) GRIP (GENTLE) GRIP

Inflatable grippers can help solve tough clamping problems

This footed bladder clamp holds pieces together for bonding or machining. Inflating the bladder lifts the clamping plate while springs ensure proper opening.

Bob Paugh and Ken SterryPawling Engineered Products Pawling, N.Y.

Get a Gentle Grip - 7327 R

Rigid mechanical and magnetic clamps are fine for most industrial gripping and positioning. But what if the piece is too fragile or irregular for point-source grip- ping, or the factory environment is too cor- rosive or hostile? Or perhaps you want to cut costs and parts from the clamp or just make it better for a small added cost?Maybe you should be thinking of a blad-der clamp, which is essentially a rubber pillow that inflates and deflates on com- mand. Bladder clamps reduce breakage in ice-cream cone bakeries, lug 500-lb engine blocks around foundries, and manipu- late brittle graphite electrodes for blast furnaces. They’re also beating corrosion in paper-making and handling machines and accurately positioning aerospace parts during adhesive bonding and rivet- ing. And in many observatories, bladder clamps handle the delicate job of shut- tling giant — not to mention brittle and priceless — telescope mirrors in and out of place for periodic cleaning. Breaking a mirror there goes way beyond seven years of bad luck.Unlike most other clamps and grippers, bladder clamps distribute force evenly over the entire contact area and conform to mildly irregular surfaces. This latter feature is often the main reason they are used. By nature, bladder clamps also damp out vibrations. And being nonme- tallic, they introduce no contaminating lubricants or sources of sparking and electrical shorts. This is why they’re often found in munitions and fuel handling and other “clean” operations.Bladder clamps are inexpensive com-pared with automated mechanical, pneu- matic, and magnetic clamps. They also fit more easily into cramped spaces.

FOUR BASIC PROFILES

Footed clamps simplify mounting and Once you settle on a bladder clamp in principle, it will pay to begin with a stan- dard profile if at all possible. Here are the four most popular profiles for bladder clamps:

Edited by Stephen Mraz

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