mechanical and fluid systems
Soft Mate Lifting Device
The Soft Mate lifting device is a below-the-hook tool that provides initial and gentle contact between mating connections while using a crane. The device utilizes a set of rolling lobe airbags to add a pneumatically adjustable soft spring into the lift rigging of a crane. The device is particularly useful for NASA's testing of the SLS, which requires the assembly and disassembly of hundreds of threaded load lines. While the load lines have relatively large diameter threaded connections to join components, the fine threads can be easily damaged by impact or misalignment. The added softness of the Soft Mate's airbag system helps maintain a neutral load on the threads to prevent galling as they are manually screwed or unscrewed. The current state of the art in precision placement of objects by cranes is a below-the-hook hydraulic system that does not add any elasticity in the lift rigging and requires the user to constantly adjust the hydraulic pressure to maintain a neutral force on objects being joined. By virtue of the pneumatic core, the Soft Mate lifting device provides the needed elasticity while minimizing user interaction during lifting and placement. Although designed particularly to aid in NASA's SLS threaded load line assembly, the extra compliance provided by the Soft Mate system may also benefit other applications where additional control and precision are required for placing or mating heavy components. The Soft Mate design has undergone extensive stress analysis and is based on commercially available components that can be scaled and optimized for different weight requirements. The system provides the flexibility needed to assemble heavy components with threaded connections or other precision crane placement applications where greater compliance is needed.