|Instant Access. Workers maneuver the loaded arm from above and below.|
A crane mechanic grew tired of watching high-rise workers struggle to deliver building materials to upper floors, so he invented a device to make the job easier.
Eitan Leibovitz, 61, calls his creation the "Magic Arm," an under-the-hook lifting attachment designed to replace landing platforms and hoists. "Everybody is trying to bring the load inside the building; I brought the crane inside the building," says Leibovitz, chairman of Israel-based ConTex. view video |
The first prototype arrived last year and Leibovitz has already sold about 20 units. Nycon International Inc., a concrete-product supplier in Westerly, R.I., recently discovered the invention and plans to import it in North America.
After the firm finishes demonstrations and testing in the U.S., it expects to introduce the attachment at a discounted price of $16,000. It normally retails for $20,000, according to Frank Gencarelli, Nycon chairman. Testing the device to make sure it meets U.S. standards will take several months, he adds.
The C-shaped arm weighs 375 kg and comes in five sizes to match different floor-to-slab heights. ConTex also builds custom models, Leibovitz notes.
Forming the arm are three tubular-steel channels, welded together and plate-reinforced. On its longest side, the top beam, is a steel wheel that guides the arm over a ceiling slab. The wheel rolls the arm in, the crane operator keeps lowering the line and a 12-mm wire rope automatically releases the load on the floor below. The wheel, which takes the weight of the load, bears on the ceiling several feet in.
Rigged to a crane at one end, the rope reeves into the Magic Arm via three internal sheaves, where it dead-ends inside the bottom beam. A hook block below the beam carries the load. The device is rated to hold 1.5 tonnes of material and has a design factor of 5:1.
According to Jerry D. Harper, a project manager for Summit Construction Co. Inc., such attachments have potential to improve safety and cut costs. He is planning a $135-million hospital addition near Indianapolis and is "trying to brainstorm how were going to feed this building without landings," he says.
(Photos by Tudor Hampton for ENR)