How can linkage backlash be controlled?

How can linkage backlash be controlled?

• A. Use springs or other compliant elements to axially force nut halves against opposite flanks of the screw thread
• B. Increase the preload on the main spring
• C. Weld the nut halves together
• D. Use locking tighteners to lock the nuts

Answer: (A)

Backlash in a screw-nut linkage comes from clearance between the threads that allows motion to occur before the motion of one part translates into the other. The most effective way to control this is to apply a constant axial preload that keeps the nut halves pressed against opposite flanks of the screw thread. Springs or other compliant elements push the halves together so the threaded engagement remains tight as direction changes, eliminating the gap that creates backlash. This method directly addresses the root cause by maintaining engagement under load, improving precision and response. Increasing the preload on a main spring, welding the nut halves together, or using locking tighteners would not provide the same reliable, adjustable control of thread engagement and can introduce excessive friction, binding, or loss of adjustability.

Backlash in a screw-nut linkage comes from clearance between the threads that allows motion to occur before the motion of one part translates into the other. The most effective way to control this is to apply a constant axial preload that keeps the nut halves pressed against opposite flanks of the screw thread. Springs or other compliant elements push the halves together so the threaded engagement remains tight as direction changes, eliminating the gap that creates backlash. This method directly addresses the root cause by maintaining engagement under load, improving precision and response.

Increasing the preload on a main spring, welding the nut halves together, or using locking tighteners would not provide the same reliable, adjustable control of thread engagement and can introduce excessive friction, binding, or loss of adjustability.