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Plain bearings in electric wheelchairs

drylin linear plain bearings work reliably in electric wheelchairs under high loads

The products of Motion Solutions GmbH – electric wheelchairs and rehabilitation therapy systems – are all about the mobility of the people who use them. The products themselves are also extremely mobile – for example, the active seating system for wheelchairs, which can be adjusted in various directions, or the heavy-duty wheelchair for people weighing up to 350kg. In the construction of these devices, the designers use our construction kit of maintenance-free plain bearings.

Profile

  • What was needed: undefined
  • Requirements: Resistance to outdoor use and high loads; a maintenance-free and lubrication-free profile guide.
  • Industry: medical equipment
  • Success for the customer: A mechanism optimally adapted to the body's own joint functions.
Delordosing System from Motion Solutions

Problem

The Motion Solutions GmbH – 'moso' for short – has set itself the task of ensuring or maintaining the mobility of its physically disabled customers. The company develops and manufactures a wide range of tools that are characterised by innovative functions, for example, by the special mobility of the seat systems.
For people who cannot stand on their own, Motion Solutions customises and distributes the "EasyStand Evolv" standing trainer. They bring the user into the standing position at the push of a button and without any other intervention. This strengthens the active and passive musculature, stabilises the cardiovascular system, treats contractures and brings the users to the same level as their standing fellow human beings.
The structure of such a device is anything but simple. The mechanics must be adapted to the body's joint function. During the entire standing up process, shearing motion should not occur on the backrest or on the seat surface, and all system components that touch and guide the body must be in the same positional relationship throughout the entire standing up and sitting down phases.
In addition, it has a so-called "delordosing", which brings the pelvis into the orthopaedically correct position when standing, by shifting the seat surface according to the user's needs as an additional movement.

Solution

The moso engineers have implemented this push-out with a undefined, or more precisely a drylin WJ200QM housing bearing with an angular contour , which exerts a leverage effect on the delordosing system . It runs on a profile rail guide and is equipped with a clamping device, which synchronises the radius of movement in relation to the standing. This is just one of many examples of the use of igus plain bearings in Motion Solutions' rehabilitation equipment and wheelchairs. For more than ten years, the designers have been using the exceptionally compact plain bearings, which do not require lubrication and are suitable for outdoor use without restrictions. The bearings have to prove that they are also suitable for high loads in other devices in the moso product range. Prime example is the "Leo 350 XXL": An electric wheelchair for people with disabilities, who weigh up to 350 kilograms and are up to 2.20 metres tall. The wheelchair itself is extremely manoeuvrable and compact. Here, for example, in the longitudinal adjustment as well as in the (optional) height adjustment of the seat system, drylin® linear guides again provide for mobility and stability. The seat tilt can also be highlighted, which means that the seat can be tilted upwards to the rear by 45 degrees and forward, as an entry and exit aid. Here, plastic bearing bushings are used as well as in the drive and steering system of the Leo 350. They also prove themselves in the case of high mechanical loads such as shocks caused, for example, by driving over the curbs, as well as by the twists to which the chassis is subjected in practice.

Innovation: Active seat module with cardanic mobility

A new development of Motion Solutions is an active seat module, which is installed in existing wheelchairs and provides an astonishingly high degree of mobility: the user can bring the backrest and seat into the overhead position. However, the seat can also be tilted forward in the other direction by up to 33 degrees as a standing-up aid. In addition, the entire seat can be inclined to either side by 20 degrees. Since the movements can be superimposed, the user ultimately sits as if on a large ball, which keeps the body secure in every position.
This is by no means just a gimmick, but supports the health of the physically handicapped. A healthy person, who sits, always shifts his position. This is often not possible for an electric chair user . The possible consequences are circulatory disorders or even open pressure points. With the seat module, the user can shift position and specifically promote blood circulation or simply transfer by standing. All the angles of the seat system can be programmed in such a way that one side and then the other, is pressure-relieved automatically and alternately.
Here, too, the mobility of the user is supported - with extremely movable drive systems. The shears of the cardan system, which are protected by a pair of bellows, are equipped with our undefined. And the designers of Motion Solutions not only use the plain bearing modular system but also the system components of the second business division of igus: our undefined are also used for the energy supply to the movable and adjustable components of the electric chairs.

More pictures of the application example

LEO 350 XXL compact electric wheelchair for people with a body weight of up to 350 kg

With the LEO 350 XXL, Motion Solutions has developed an extremely manoeuvrable and compact electric wheelchair for people with a body weight of up to 350 kg.

Delordosing system of the standing exerciser

The "delordosing" of the standing exerciser is implemented via a drylin W profile guide from the igus modular system.

drylin linear bearings

The height adjustment of the LEO seat is guided by drylin linear bearings from igus.

Longitudinal adjustment of the seat via linear bearings

The longitudinal adjustment of the seat is also guided by the drylin linear bearings from igus.

Energy supply to the electric chair components thanks to e-chains

The e-chains from igus enable the energy supply to the electric chair components.