Bonding Improves Comfort and Convenience for Wheelchair Users

Bonding Improves Comfort and Convenience for Wheelchair Users

DELO makes wheelchairs lighter

A trend towards light-weight construction is not only seen in the automotive and aerospace industries, but also when it comes to wheelchairs. LEVO provides latest technology solutions for people with walking disabilities to facilitate their daily lives, offering them independence, mobility, and flexibility. A two-component epoxy resin adhesive from DELO is used in the frame of LEVO`s standing wheelchair and ensures stability and security, tested and certified by an independent organization.

The Swiss LEVO AG was founded in 1974 and has ever since been developing innovative technologies to make life easier for people with walking disabilities. The stand-up wheelchair is certainly one of its most important developments.

The active wheelchair "LEVO Summit EL" features an innovative design and an excellent stability for a secure upright position. Its backrest is foldable and with a weight of only 21 kg, it is the lightest wheelchair with electric stand-up function available on the market. This light weight is also due to the use of adhesive bonding for joining components.

LEVO Summit EL in standing position (Figures: LEVO)

Reliable Bonding of Multiple Materials

When it comes to joining components of various materials, bonding is the most suitable technology. In the case of the LEVO wheelchair, reliable joining is required for the carbon and aluminum parts of the wheel axle as well as steel and aluminum elements of the frame. Mechanical joining elements such as screws or rivets, would not only damage the fiber structure and weaken the component during preparatory work, but also involve more time-consuming procedures.

The adhesive also has to withstand a temperature of 180 °C which occurs during the subsequent powder coating of the bonded components and the simulated crash tests with the wheelchair acting as a car seat. When selecting the appropriate adhesive, the wheelchair manufacturer additionally attached great importance on easy processing and simple handling during the manufacturing process. DELO and its partner Credimex AG from Alpnach (Switzerland) therefore recommended the use of a two-component epoxy resin and Credimex ran several tests in its laboratory:

  • Strength of the bonded components after storing them in the oven at 180 °C for 30 minutes
  • Bonding and dispensing tests
  • Tests aiming to determine the proper surface pretreatment
  • Discussions on the optimal design of the bonding geometry

After these tests, a pressure text was successfully conducted to assure the safe use of the technically sophisticated bonded connections.


It All Depends on the Right Adhesive

The two-component DELO-DUOPOX adhesive used for the LEVO wheelchairs cures at room temperature (approx. 23 °) after mixing resin and hardener. Due to the use of the DELO-XPRESS dispensing guns the manual processing is fast and simple, as requested by the wheelchair manufacturer.

As a high-strength structural adhesive, DELO-DUOPOX is often used for joining rods of diverse types and, in the case of this active wheelchair, it is used for bonding the entire frame. The adhesive can serve as a constructive element, since almost any layer thickness is possible. In addition, its viscosity provides sufficient flow resistance to allow the components to be joined manually and ensure a smooth production process.

Conclusion

Requirements for wheelchairs are obvious: they are supposed to make life easier for their users, giving them more independence and mobility. With the use of adhesives wheelchairs are reliable and even lighter. DELO's epoxy resin thus makes a small contribution to the success of the Summit EL standing wheelchair from LEVO as the lightest manually and electrically propelled standing wheelchair on the market.