1、Lessons Learned Entry: 0576Lesson Info:a71 Lesson Number: 0576a71 Lesson Date: 1996-08-01a71 Submitting Organization: JSCa71 Submitted by: Jim Horn, Matt Martin, & Walter ClintonSubject: Use of Mechanical Stops to Restrict/Prevent Equipment Rotation/Movement Description of Driving Event: When a test
2、 fixture was commanded to rotate, the rotation machinery was actuated but the fixture failed to rotate. Visual inspection of the fixture revealed deformation and damage of several fixture components. The drive system had a mechanical stop in place to prevent over-rotation of the fixture cradle. Subs
3、equent analysis indicated that the drive system had sufficient torque capability to overload the drive train should the drive train operate after the mechanical stop was engaged. Damage to the test fixture was estimated at $20K.Lesson Submitted from the Boeing International Space Station (ISS) Lesso
4、ns Learned Database:From Boeing ISS dated 8/96, was entitled “Rotating/Moving Equipment Mechanical Stops“Lesson(s) Learned: Use of limit switches or position indicators are better alternatives to mechanical stops to preclude excessive mechanical movement.Recommendation(s): a71 Limit switches and pos
5、ition indicators are better suited to provide the primary means to stop or limit movement of a rotating / moving device.a71 System drives should not be designed or programmed to operate when a mechanical stop is engaged.a71 Mechanical stops should be utilized only if excessive movement or rotation w
6、ill result in damage to the hardware or fixture or result in unacceptable operational hazards.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/A
7、Additional Key Phrase(s): a71 HardwareAdditional Info: Approval Info: a71 Approval Date: 1997-10-31a71 Approval Name: Ronald A. Montaguea71 Approval Organization: NA3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
