An integrator building a system for Boeing Aerospace Company had a strict requirement for a “Zero Backlash” rotation system for positioning of reverse thruster part as it was being assembled. The reverse thruster and carriage had a total load of 4000 lbs. The end customer specified the positioning system must have a 5:1 safety factor. The payload had a physical size of 140”x 80” x 60”. The positioning system also had to be manufactured to allow for slight misalignment. The system also had to be equipped with a safety locking device to prevent positioning system from moving during maintenance or if operators were in cell assembling parts to reverse thruster.
SOLUTION
Motion Index Drives barrel cam programmable trunnion model RT400-Flex fit the end customer’s specification. Our RT series RT400-Flex is equipped with a programmable barrel cam. The barrel cam/cam follower mechanism operates in a preload condition allowing for a true “zero backlash” operations. Unlike gear reducers that must have backlash in order to operate, the barrel cam must operate with zero backlash to correctly operate. The barrel cam solution is the only true “Zero Backlash” rotation mechanism on the market today. Our case hardened barrel cams (5 mm depth) and needleless cylindrical cam followers allows for maximum torque to be generated. The custom floating bearing assembling on the tail end, opposite of the RT400-Flex unit allowed for slight misalignment. The tail end bearing assembly was able to float in and out to accommodate any structural size differences that may occur from expansion and contraction. We equipped the RT400-Flex with a safety lock out device and custom output flange to give Boeing plenty of option to engage the safety lock-out device at multiple angular positions.
