摘要 |
A screw fastener includes a first screwdriver including a first bit configured to fasten a first screw by engaging with a recess of the first screw, and a first motor configured to rotate the first bit, a second screwdriver including a second bit configured to fasten a first screw by engaging with a recess of the second screw, and a second motor configured to rotate the second bit, an elevator unit configured to simultaneously ascend and descend both the first screwdriver and the second screwdriver, and a controller configured to control the first motor and the second motor so that seating of the first screw can start after torquing-up of the second screw starts.
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