Why Electric? Why electric height adjustable tables?

The focus of applied ergonomics should be to make the workplace a safer more comfortable environment for each individual operator. Appliances that operators are required to use should be "user friendly", or easy to use. Tables should be invisible to the task, no legs to bang knees on, plenty of toe and leg room when sitting, the correct size, sturdy, and easy to adjust.

Mechanical and hydraulic height adjustable tables that use manual hand cranks are not user friendly. For safety sake the hand crank is usually stored out of the way when not in use. The first issue the operator has to deal with is extracting the crank - not always easy to do. Once pulled out, some cranks can require up to 60 in lbs. of force to turn, even with small loads on the table. This is more than any 5th percentile female should be asked to deal with.

Any load on a crank table is fed directly back to the operator. As the weight on the table increases the crank becomes harder to turn. Remember, the weight on a true ergonomic table, where the uprights move with the work surface, includes the weight of the work surface, uprights, shelves, lights, drawers and any objects on the work surface.

Most mechanical height adjustable table designs originated in Europe in the early seventies. Some have attempted to copy these designs using trailer jacks (from boat or camper trailers) in the legs to lift the work surface. These inexpensive jacks don't perform efficiently or smoothly. Motion is coupled from the hand crank to these jacks in the legs via gear transmissions or bicycle style chains, inefficient and maintenance intensive. To provide sufficient mechanical advantage, crank tables require 7-8 turns of the crank for every inch of work surface height change. If an operator needed to raise the work surface six inches they would have to turn the crank through 42 to 48 complete rotations. To change from the lowest to the highest surface position, (16") the crank would have to be turned 112 to 128 times, not user friendly.

Hydraulic tables use cylinders in their legs connected via tubing to a hand pump to move the work surface. Although smoother in operation, and generally more efficient than mechanical tables, they tend to be expensive, and the potential for leaking hydraulic fluid makes then undesirable in clean environments. Hydraulic tables also require 6-7 turns of the hand crank for each inch of height change. They also feed back increased loading to the operator, the heavier the load, the harder to adjust. Again, these tables do not deal with weight well and do not make good sit-stand tables.

The bottom-line....crank tables are hard to adjust so operators don't. As more firms become aware of this fact, they are switching to user-friendly, efficient (115vac @ 1.6 amp full load) Boston Technical Furniture electric adjustability. Electric height adjustable tables, once viewed as an extravagance, have become a cost effective, maintenance free, practical alternative to crank adjustable tables.