Using some of the left over wood from the demolition of the backyard roller coaster, I decided to embark on another carpentry project. To start, I created the first iteration of drawings for the hammock in Autodesk Inventor and went out to gather the supplies. The original design consisted of two long 4x4s being bent using a technique called Kerfing where evenly spaced cuts are made into the wood with a thin spine being left at the bottom of each cut. Once I completed the first design, it was fairly obvious that there were some pretty serious design flaws. For one, the hammock was too short and unless you were positioned perfectly with your mass spread out, you would touch the ground. The other problem was that the original design only called for a piece of steel on the top of the bent wood with screws being used to keep the member's shape. This proved to be insufficient as one of the two bent members snapped under the load of a person. This design can be seen below.
After the first design broke, it was time for V2. A number of major changes were made to the design. First, steel plates were placed on both the top and bottom of the bent wood and bolts were used to secure the member in place instead of screws. Second, the members were split into two so that the arms could extent higher up. Finally, angled members were used as the support instead of the original lateral braces as they could be secured more easily and located higher up on the arms. Afterwards, the wood was stained and the steel was painted with a rust proof paint to ensure that the hammock could be used outdoors. For anyone interested in recreating the design, the CAD drawings can be downloaded below though some interpretations will have to be made as the drawings are not 100% build ready.
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| hammock_drawing.pdf |
