Rocking lounger - Design brief
My initial motivation to design this lounger was to fill a gap in the garden furniture market. For me, the products available suffered either from being overly static or required moving parts to adjust the angle of recline. I wanted a product that allowed both these limitations to be addressed simultaneously and to provide a fresh and distinctive design to the market. I placed the following restrictions on my design from the outset-
1. The cost of construction needed to be kept to a minimum and utilise reclaimed pallet wood to adhere to my strict budget.
2. The design had to have the ability to be crafted in a limited workshop using hand tools and domestic D.I.Y. appliances.
3. A degree of collapsibility was required for seasonal storage.
4. An ergonomic feel and a dynamic appearance were essential to separate the design from the existing products on the market.
Design development
The initial idea centred on curved runners that allowed the user to choose an angle of recline depending on where they positioned themselves. I immediately saw the possibility of combining a stable reclining mechanism with the added ability to utilise a swinging or rocking motion.
I began sketching ideas on how I could address the two objectives. The mechanism of swinging and rocking are very different but achieve a similar goal. Swinging relies on suspension from a central axis above, but rocking relies on an arc of support from below. Utilising the rocking motion was the obvious choice to allow a more compact design, retain the ability to hold varying degrees of recline and to fulfil the design brief of no moving parts.
During my research I discovered an extraordinarily delicate relationship between the radial centre of the rocking arc, the average persons body mass distribution and the range of movement required. If the arc radius is too near the centre of mass the result will be instability; too far and the rocking motion cannot be achieved.
I required a compound curve that descends from the backrest for spinal support, into the active rocking arc below the pelvis and then support for the thighs, knees and lower legs.
Maquette to test arc alignments.
For added comfort I needed the horizontal slats to provide enough room to allow for a little spread of the arms and legs. This necessitated the introduction of a ‘waist’ to the bed for ease of mount and dismount. As well as giving the design a distinctive look it allows easy access to items such as drinks that are placed on the floor.
Graphical arrangement.
Below you can see the final 3D CAD model along with the product construction. The slats, nylon webbed straps and locating pegs form the removable bed surface that can be rolled for seasonal storage. The frame is also collapsible.
Product testing. Experimentation on the range of movement.
I learnt a great deal from this prototype, and I am astonished by it's sensitivity. You can rock the entire lounger by moving any part of your body and in doing so, changing your centre of gravity; lifting your chin, arching your back, raising your arms or legs, to name but a few. The body movements required for using a park swing are remarkably relevant. It is simple to do but is something that must be learnt none the less. I find the final look pleasing as there are very few straight edges when viewed from any angle and I feel this satisfies the brief of an ergonomic appearance.
Given access to either lamination or CNC milling equipment, a design improvement would be to apply a three dimensional curve to the runners allowing them to maintain the lateral profile but also follow the perimeter of the bed. This would also allow the slats to be inset within the runners to avoid exposing the end grain.
Final product promotional video.
Now get comfortable, gently rock and allow your mind to 'drift' to a higher level of relaxation.
Thank you for taking the time to view this post and I welcome any feed back you can give to help me improve the design.
Thank you for taking the time to view this post and I welcome any feed back you can give to help me improve the design.
Thank you for watching!
