Specs for Suspendulum® Free-Standing Suspension Frame

Testing of weight capacity, as well as material strength and endurance, commenced in the year 2004. The US Utility Patent #7,172,512 was obtained in 2007.

A certificate of Structural Soundness has been issued by a Professional Engineer in 2013.

Recommendation of weight restrictions are as follows:

When the Suspendulum® rig is configured as a Swing for recreational purposes or to suspend for Aerial Yoga, with leg tube wall thickness of 16-gage, may safely suspend weights up to 400 lbs. and 500 lbs for 14-gauge wall thickness.

Set up for Aerial Dancers, a safe weight limit using 16-gauge is 180 lbs and 220 lbs with the 14-gauge. Material strengths for the rig are shown in the following illustration.

If you wish to view the Structural Engineers certificate please

Parts Load Descriptions

The effects of two different types of loads are of concern regarding the structure known as the Suspendulum®. Dead loads verses live loads. Dead loads (static loads) are considered permanent loads and vary only with regard to the weight of the individual aerialist or swing vehicle occupant. Live loads such as dynamic weight changes from performing “drops” change the value of forces applied to the structure.

The Suspendulum® is a tetrahedron. The loads bearing down on each of the legs is in direct proportion to the weight applied to the leg closest to the weight being applied; i.e. when the load is aligned with any of the legs that leg bears the load. When the load is aligned halfway between the supporting legs both legs share bearing the load.

Each leg is composed of steel tubing that has a compression rate failure above 40,000 lbs. In order to swage the ends of the tubing 40,000 lbs. of pressure must be applied in order to squeeze the tubing into a swaged form in order to make one end of the tube fit into any other non-swaged end. The four inch swage insures against bending of the tubing. Leg tubing are inserted into 4 inch swage with spring-button to assure depth of fit into adjoining tubing.

The quarter inch thick mounting plate holding the legs in place at the apex (top) is rated at 36,000 psi made from hold rolled A36 Carbon steel. Swing bolts attaching the steel tubing to the mounting plate are made from hot-forged steel.

The u-bolt with which the user attaches various vehicles to is made from forged metal bases meeting or exceeding all requirements of ASME B30.26 including identification, ductility, design factor, proof load and temperature requirements. Importantly, the u-bolt used for the apex of the Suspendulum® meets other critical performance requirements including fatigue life, impact properties and material traceability, not addressed by ASME B30.26 and meets the performance requirements of Federal Specification FF-C-450 TYPE 1 CLASS 1

The O-ring attached to the u-bolt at the apex has the following criteria:

Uses for Military/Parachute 1298-1 11-1-599 Cargo/Fall Arrest/Safety 1298-1S Hot Forged Alloy Steel Thermal Treated
Cadmium, Zinc Plated 100% Proof Load Tested @ 15.3 KN (3,600 lbs) Meets or exceeds PIA-H-7195 Meets or exceeds ANSI Z-359.2

The cables used to keep the legs from splaying outward and hold the tetrahedron shape in place have a 3/16” x 7/19 strand format normally used for aircraft cabling and has a breaking strength of 1920 lbs. The quick-link holding the cable to each foot assembly has a working load limit of 1900 lbs.

  • Read and follow all operating instructions and all manufacturers specifications, instructions,
    advice and assembly and maintenance requirements for use of the equipment.
  • Use only manufacturer recommended compatible components
  • Periodically examine and replace ANY defective, worn or deteriorated component part. Contact Customer Service.
  • Examine all related gear and equipment, including all fittings, fasteners or webbing before each use.
  • Do not exceed recommended or stated forces, speeds, or other factors regarding safe use of the equipment.
  • Read and follow all warning labels, manuals, instructions, training or experience requirements and recommendations
    and all recognized use procedures.
  • Do not be over confident and listen to your intuition.
  • Be extremely careful and cautious.
  • Make sure frame is set up on level ground or compensate for uneven ground with the help of a professional landscaper.
  • Do not use in High Winds or during Lightning Storms
  • Disassemble for storage during long periods of non-use.
  • Wear gloves to protect your hands upon assembly and disassembly.


By Zen Swing®


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