Ladder design hasn't changed much since early man bound cross sections to two parallel sticks and formed the first ladder. There were a couple of improvements on the basic idea: the step ladder (one that stands on its own) and the extension ladder. That was about it.
Until 15 years ago, that is.
In 1971, a West German engineer, Otto Mayer of Pluderhausen, took an interest.
The breakthrough came two years later when he perfected a ratchet-type hinge that could lock securely in place at three different angles, opening the way for the multipurpose, ``one ladder does it all'' piece of equipment.
From Germany the idea spread out across Europe, but it took more than a decade to cross the Atlantic in its multi-hinge form.
At the National Hardware Show in Chicago this year, several brand lines of the new ladder, some manufactured in the United States but most imported, were on display for the first time.
By incorporating three hinges, the new design can be locked into a straight-ladder position, become a double or step ladder, a platform or push-away ladder, be shaped into a scaffold, form a table base or work bench, or be adapted to the unusual requirements of a stairwell or ramp, among other things.
Finally, it folds away readily for storage in a cupboard or for ready transportation in the trunk of a car.
David Lambert of Muskego, Wis., who sells the original ``Versaladder'' designed by Mr. Mayer, says 60 percent of his sales are to homeowners, 40 percent to professionals.
``They all have staging and other specialized equipment, but they keep one or two multipurpose ladders on hand for minor repair jobs, or to use at sites when they take measurements for an estimate and so on.''
Peter Perlmutter of Lynnfield, Mass., who sells a competing brand made by Little Giant Industries puts his sales at slightly ``better than 50 percent to the professionals,'' but points out that the Utah company makes a particularly heavy-duty version specially for the professional market.
The Little Giant design is a modified version of the multihinge types.
With only one hinge, it's slightly less versatile (the ladder can't readily be formed into a table), but has greater adjustability (it can be lengthened at one-foot increments and can be formed into two separate scaffold tressels).
Because the ratchet hinge is the ``new'' feature of these unusual ladders, many would-be buyers express concern about its strength. But manufacturers claim that the hinges have invariably been the last component to break down in tests to destruction.
With some 100,000 ladder-ralated accidents recorded each year, companies say they cannot compromise on quality. The new ladders meet all federal safety standards.
The Demarco Corporation of Des Plains, Ill., has gone even further. It maintains a full-time representative of Underwriters Laboratory in Germany where its Krause ladder is made so it can maintain its UL listing. The Krause ladder is the only one to claim UL listing.
Before investing from $100 to $500 in one of these new ladders, ask the manufacturers if all parts are replaceable and, if it's important to you, if the ladder comes fully assembled.
It is also advisable to inspect the ladder personally and have a salesman demonstrate its options. For details, write to: Dumarco Corporation (Krause), 2804 W. Le Fevre Road, Stirling, IL 61081. Tel.: (815) 626-0022. Little Giant Industries Inc. (Little Giant), 2241 South Larson Parkway, Provo, UT 84601. Tel.: (800) 547-5995. Versa Products Inc. (Versaladder), PO Box 905, Muskego, WI 53150. Tel.: (414) 422-9010. WestWay Products Corporation (Pal), 31878 Camino Capistrano No. 270, San Juan Capistrano, CA 92675. Tel.: (714) 240-1311.