How we build the wheelchairs and handbikes
Our wheelchair and handbike frames are made of 7020 (AIZn4.5Mg1) aluminium. This is the strongest aluminium alloy that can be welded. It is more rigid than any titanium alloy. It is the preferred alloy for armoured vehicles, motorbikes and bicycle frames. Our unique Sigma Tubing technology optimises strength during the manufacture of large tubes with thin walls. Together, these achieve an extreme stiffness-to-weight ratio. The result is ultimate stability.
Wolturnus always employs TIG (Tungsten Inert Gas) welding. Combined with a protective argon-helium gas compound, this prevents grains from developing during the welding process. This ensures that the material retains its maximum strength.
Any tension that has arisen during the welding process is eliminated by heat-treating the frame at a very high temperature afterwards. The frame is then measured and any necessary adjustments are made to ensure that the final product is perfectly aligned. Finally, the frame is hardened by a process of precisely calculated temperature changes that restore maximum strength to every single microgram of aluminium.
Anodising is a process that enables integral colouring, increases corrosion resistance and hardens the surface. A layer of aluminium oxide is added to the aluminium surface. Aluminium oxide is one of the world’s hardest materials. It measures 9.7 on the 10-point Moh scale of relative hardness. (Diamonds: 10. Glass: 5.6.) The surface treatment results in an incomparably hard-wearing and maintenance-free surface. It ensures the ultimate in corrosion-resistance. It creates a coloured, durable surface that is resistant to dents and impacts. Anodising is the primary surface treatment used by Wolturnus.
Wheelchair users know how important a healthy and comfortable seating position is. An incorrect seating posture in the wheelchair can cause pain and discomfort. That is why all wolturnus wheelchairs are designed with a healthy seating posture in mind. It is important that the ischial tuberosities can emerge into the support surface, and the pelvis is supported by the wheelchair’s back system. Any shear force in the wheelchair must be prevented to minimize the risk of pressure ulcers. Wolturnus wheelchairs are designed with an ergonomic frame construction, strap back and strap seat that make it possible to release pressure and adjust the wheelchair down to the last millimeter to fit the user.
Ergonomic seat and strap seat
Wolturnus wheelchairs are designed with an ergonomic seat where the back of the seat is flat and the front part is inclined upwardly. We call it an ergo seat. The ergo seat stabilizes the pelvis in an upright position. The ergo seat is always combined with a strap seat that supports the pelvis and distributes the weight from ischial tuberosities to thighbone. This prevents the wheelchair user from sliding forward in his wheelchair and optimize the pressure distribution.
The seat cushion is also very important to minimize the risk of getting pressure ulcers and to achieve a comfortable seating position in the wheelchair. To make sure that you get the right cushion we make pressure mappings of all or different seat cushions. We have experienced that pressure distribution is enhanced in wheelchairs with strap seats, adjusted to the user.