Reducing Operator Burden During Bolt Tightening with Impact Wrenches

CKD Corporation, Komaki Plant

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At CKD's assembly plant, impact wrenches are used for tightening overhead screws.
Previously, this task was performed using a 10kg impact wrench without any assistive devices, requiring operators to assume a hunched-over position.
This resulted in significant strain on the operators' hands, arms, shoulders, and lower backs, increasing the risk of workplace injuries.

Issues

The Use of 10kg Tools Led to Significant Physical Strain on Operators

The Use of 10kg Tools Led to Significant Physical Strain on Operators

Prior to implementing the Compact Arm, operators were using a 10kg impact wrench held at shoulder height while leaning forward, which presented several challenges:

- The awkward posture put excessive strain on the arms, shoulders, and lower back.
- The reaction force and vibration from the tool caused significant strain on the wrists.
- This task could only be performed by a limited number of operators.

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Reasons for Choosing the Compact Arm

The mobile design eliminates the need for work area modifications.

The mobile design eliminates the need for work area modifications.

During the Compact Arm's development phase, we conducted on-site interviews with production engineering and operations teams to identify areas where tool assistance could address existing challenges.
In this particular application, the work area varies daily, and production volumes don't justify robotic automation. For these reasons, manual screw tightening was the standard practice.
However, the Compact Arm's mobile design, which allows it to be easily moved with a dolly, eliminated the need for any work area modification, making it an ideal solution.

Results after introduction

A Safer Working Posture Significantly Reduces Physical Strain

A Safer Working Posture Significantly Reduces Physical Strain

After Implementing the Compact Arm:

- Operators can maintain a safe, ergonomic posture, minimizing physical strain.
- Reduced reaction force and vibration ensure safe, continuous operation.
- The task can be performed by a wider range of operators and the burden on the wrist, arms, and lower back was greatly reduced.

Video Overview