Childhood experiences have immense impact on forming the relationship between people of different abilities. Through joint play a basis for trust and belonging can be built, whilst separation leads to prejudice, fear and isolation later in life. Wheelchair accessible playground equipment, like wheelchair swings, which are not suitable for joint play, despite the best of intentions are creating experiences of isolation and are working towards the development of the social stigma from an early age.
During my bachelors thesis project Körhinta – Carousel for inclusive play I was working on creating a playground toy where real joint play is possible.
Research and collaboration
Next to the desk research I was conducting research concerning the physical and emotional environment of wheelchair user children. In collaboration with MEREK (Rehabilitation Centre for Physically Disabled People) and Mozgásjavító (Kindergarten, Elementary and Specialized Secondary School, Unified Special Education Methodology Centre and Students’ Residence) I conducted interviews with carers, parents and wheelchair user children. I was also conducting observation research and interviewing on public playgrounds to get a grasp on attitudes towards physical disabilities, wheelchair users and a more inclusive play experience. Manufacturability and costs were also considered in collaboration with Faberland, a company specialised the design, manufacturing and installation of playground equipment.
The engineering design of the Carousel included the following:
- the hand grips
- a spring based closing system for the wheelchair compartment,
- a secure brake system,
- selection of bearings and
- structural calculations.
Public playground carousels, designed only for able bodied kids, are equipped with a single handgrip which has a double role: rotating and breaking. This design, however, isn’t suitable for use with a wheelchair. The structure is not sturdy enough to support the weight of an electric wheelchair, which can amount to 100 kg. A heavier support structure further augments the rotating mass, increasing the rotational inertia of the carousel to the point where it is not possible to stop the rotation by hand. To keep the play safe, the Carousel has an assisted break system, operated by a second handgrip.
The break handle needs a distinctive appearance and tactile sensation, to clearly communicate the difference in role.
Closing handlebar of the wheelchair compartment
The hand-bars for this part of the roundabout have to be easily opened and closed, even with limited strength. But safety is equally important. The closing hand-bars are therefore operated with a spring cylinder to aid in the opening and also to lock it in closed position.
The operation principle of the break system is based on the friction clutch. The turning of the break handle is compressing the springs that keep the surfaces apart. The system is designed in a way that the break can stop the rotation within a maximum of 10 seconds (considering the different scenarios possible with regards to the number of players at the same time and assuming limited grip and arm strength as the players are children with different abilities).
Bearing selection and structural calculations
The loads are supported by a welded steel structure, and the rotating shaft is based on ball bearings. The verification of the bearing system has been conducted for static and dynamic loads.