Soft Mate Lifting Device

mechanical and fluid systems
Soft Mate Lifting Device (MFS-TOPS-107)
Below-the-Hook Device Enabling Gentle Crane Placements to Decrease Property Damage Risk
Innovators at the NASA Marshall Space Flight Center have developed the Soft Mate system, a below-the-hook lifting device that provides initial and gentle contact between mating connections while using a crane. Cranes for lifting and lowering heavy objects are an important, sometimes essential, tool in modern industries such as construction, transportation, and manufacturing. NASA uses overhead and mobile cranes for assembly of load lines employed in full-scale testing of its Space Launch System (SLS), a super-heavy-lift launch vehicle for deep space human space exploration. Structural testing of the SLS requires precision placement of heavy objects with soft contact during mating connections, which proved to be problematic with the relatively coarse control available with motor-driven overhead cranes and existing rigging devices. In response, the Soft Mate lifting device was created to incorporate an adjustable pneumatic soft spring into the lift rigging of a crane that can maintain a neutral load while connections are assembled or disassembled.

The Technology
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.
A rendering of the Soft Mate system designed for a 3000 lb load
  • Prevents damage to heavy objects during assembly: the Soft Mate system can be precisely and gently controlled when moving and placing objects
  • Provides adjustable compliance in crane rigging: flexibility and compliance in crane rigging can be accomplished by adjusting the pneumatic system, as opposed to conventional methods such as using different sling materials like Kevlar and Nylon
  • Increases user efficiency: the addition of a soft spring in the rigging sling allows for a larger window of displacement under neutral load and reduces the need for user interaction during the lift, making the system less interactive and more efficient for mating operations
  • Enables a neutral load during operation: the user, in conjunction with the crane operator, can maintain a neutral load on mating connections without manipulating the device during the process

  • Aerospace and aviation: precision assembly of large components for satellite, spacecraft, and aircraft manufacturing
  • Construction: gentle lifting and lowering of heavy parts
  • Consumer goods: moving and positioning property that is fragile, expensive, or otherwise problematic to move via conventional rigging
  • Industrial machinery: building and maintaining heavy machinery
  • Manufacturing: assembly of heavy components with threaded connections or precision load placement requirements, particularly where minimal clearances or tight tolerances are involved, such as the installation of hydraulic cylinders and load cells
  • Marine: shipbuilding
  • Power: placement of power generation equipment
  • Transportation: railway construction
Technology Details

mechanical and fluid systems
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