| Combining brawn and brains, the Ergo arm is finding an increasing number of applications in manufacturing operations. Designed and built by Peak Industries, Inc., Dearborn, Mich., the pneumatically powered system is being used, for example, to lift and manipulate truck bumpers, minivan axles, and minivan front cross-members. All of these applications improve the ergonomics of the workstation.
One of Ergo's next assignments will be to help build Chrysler's 1998 LH cars at its plant just outside Toronto. The arm will be used to insert and center instrument panels in "bodies in white" as they move down the line. The key work here is center, since equal spacing at each end of the panel will add another measure of quality to the Chrysler LH.
Offset instrument panels and their uneven end spacing are not uncommon in current body assembly operations. They not only detract from appearance, but in some cases create interference at one end that must be corrected. Build variances on both the instrument panel and the car body can result in gap differences of up to 1/2 inch. The solution: make sure the panel is centered.
In current practice, there is a hole provided at the center of a body cross-piece and a pin molded into the instrument panel. The operator lifts the panel from a rack of dunnage and places it in the car body. Variations in pin and/or hole location lead to uneven gaps at the ends of the panel.
The Peak Ergo arm slated for use by Chrysler will have a new and smart end-effector that solves the centering problem. Manipulated by an operator, the arm locks onto an instrument panel, then centers it on a fixture at the end of the arm.
With the panel centered in the fixture, it is then ready for insertion in the car body. One of the rack-and-pinions has an arm with two pins that engage two holes, one on each side of the body in the door hinge mounting. This arrangement ensures that the Ergo fixture, and thus the instrument panel, is centered in the car.
At that point, several nuts are installed by a second operator and tightened with a nut runner. The fixture is unclamped from the panel and moved back out of the body.
A key feature of the Ergo fixture designed by Peak engineers is its use of air logic instead of servos and related electronic hardware. This keeps the system relatively simple, easier to maintain, and less costly. Most important: accurately centered instrument panels for improved quality, with no rework.
As in most other applications to date, the Ergo arm hangs from an overhead bridge (carriage) that rides on rails. The cylinder-actuated arm has an integral handle and control buttons. A balance system that produces zero gravity enables the operator to raise and lower the arm and its load with the touch of a finger and with essentially no effort.
Three buttons are used to control the arm. A High Balance button puts the arm in a transport mode. A Balance Fixture button produces the zero gravity condition. And, a Low Balance button permits the arm to be locked in position when a fixed holding mode is required.
Peak Industries has been a supplier of custom automation and assembly components and special machines and systems for the automotive and other manufacturing industries since 1966.
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