Oct 4, 2011
Repairing an H-53 pitch control rod by hand was an ergonomic nightmare.
CHERRY POINT, N.C. – Fleet Readiness Center East Mechanical Engineer Scott Holcombe (AIR-4.8 Support Equipment and Special Projects) and FRC East Ergonomist Richard Borcicky (Code 6.5) teamed up to conquer ergonomic issues involving repair of the H-53 pitch control rod assembly, recently.
The issues were force, posture, repetition, compression and duration primarily to the hands and wrist during assembly and disassembly.
Borcicky explained each end of the control rod houses a two-inch long fine thread on which a nut is attached. There is also a common body part between the two ends. Both the nuts and body part had to turned by hand. The threaded parts were frequently "frozen" during disassembly due to dirt accumulation or excessive heat from the aircraft, making the pieces difficult to turn. A standard open-end wrench could be used to break the parts free, but the parts still had to be hand-turned due to the unique design of the control rod.
"One turn of the hand and wrist turns the nut or body piece about one quarter turn," Borcicky said. "That equates to just about 200 turns to move a nut or body part the inch and half it needs to travel. Multiply that by three – two nuts and the common piece – and you're talking almost 600 turns to assemble or disassemble a control rod. That places an inordinate amount of stress on the wrist joints, potentially causing carpal tunnel syndrome."
To eliminate the ergonomic stresses associated with control rod assembly operations, Holcombe developed the H-53 Pitch Control Rod Assembly Fixture. Its three prominent features include a fixture which holds the parts securely in place during assembly or disassembly; a wheel that clamps onto the body of the control rod enabling artisans to easily turn the parts without excessively twisting the wrists; and a custom-made deep socket that allows artisans to easily remove or install the nuts.
"The deep socket makes removing the parts so easy, you can turn the wrench with one finger," Borcicky said. "Scott did an outstanding job developing this fixture – all the artisans love it."
For more information contact Borcicky at 464-5165, or Holcombe at 464-5140.
FRCE Public Affairs
(252) 464-7028
