The mechanical engineering specialist Reiser AG has been working with Steinbeis experts on the development of an electrically driven walking frame Demographic change is resulting in an aging population and this is raising the importance of mobility in old age. The Steinbeis Transfer Center for Process Development in Reutlingen has been working with the Veringenstadt-based mechanical engineering company Reiser and other partners in industry on an auxiliary electric drive system for walking frames. It should be easy to adjust and help more elderly people with mobility issues, thus improving their quality of life.
Walkers or walking frames help elderly or disabled people to move around in the home but they are also used outdoors. One important factor when it comes to the medical aspects is that walkers help people with their balance, assuming they are physically and mentally in a position to use a walker. More and more people now use walkers, especially as mobility becomes increasingly important in society. The walkers currently on the market tend to consist of a metal frame with three or (preferably) four wheels, two of which are typically fixed. The two front wheels are used for steering. The top of the metal frame is equipped with support handles or two separate grips with a separate lever that is clenched to activate a brake or even a parking brake on the fixed wheels.
The main disadvantage with walkers until now is that they struggle with small obstacles under the wheels (such as cobblestones) and cannot deal with steep inclines. A great deal of force is needed from a person who may already be disabled or weak, and in some cases users can no longer move. There is another aspect that is important in this respect: According to convalescence experts, it is much better from a therapeutic angle to recover skeletal function without too much muscle intervention. Patients who have had a knee or hip operation experience less discomfort if they can start moving around again with little effort. This is now possible, thanks to the auxiliary electric drive co-developed by the Steinbeis experts. As people need to grow stronger, the drive can simply be deactivated.
Testing of conventional walking frames on different surfaces has now shown that they also have another serious drawback. All three- or four-wheel walking frames used until now have a dangerous design flaw, which can result in people falling over. This is especially the case if walkers are pushed over a curbstone. This effect is nothing new: Office chairs with four wheels sometimes tip over; chairs with five wheels don’t. As a result, the new walking frame, which has been given the brand name e-buddy, has a fifth wheel that also functions as an auxiliary drive wheel. This avoids tilting axis issues, thus eradicating this particular accident risk.
The aim of the development partnership was to adapt as many walking frames in the trade as possible by equipping them with an auxiliary, electrically driven wheel, ideally using the most simple technology possible at an affordable price. The first step for the experts involved research and analysis, based strictly on must-have requirements, must-at-least-have requirements, and nice-to-have requirements. These revolved around users with limited physical abilities. The reliability or safety of functions was of utmost importance, so even if users do something wrong, nothing bad should happen. It was interesting to hear what the biggest priority was for older users: no electronics and nothing over-engineered (in the way some modern cars or household devices are sometimes too complex).
While conducting their investigations, the project team placed emphasis on practical application. The key findings of a user survey flowed into the concept development stage of the walking frame:
- The auxiliary drive is equipped with a battery and a control box. These are fitted near the ground between the two steerable wheels, and the mounting mechanism works on an existing walking frame with a connection tube. This was important to fulfill the safety prin ciple of “five-legged contact with the ground.”
- The design is deliberately based on a small number of components, making it possible to keep the weight down to just 6.9kg, most of which is accounted for by the battery.
- The entire auxiliary drive can be removed from the walking frame without tools thanks to a coupling system. Everything can be folded as usual and stowed in a car.
- The coupling system is 3D printed and can be used to attach the auxiliary drive to any standard walking frame. To make the system easier to assemble, the contact area of the coupling device is self-aligning.
- Walking frames can be used in the same way as now, even without activating the auxiliary drive. If the user is walking down a slope, the system gently brakes the wheels.
- The frame has a special pull function that makes it easy to walk over curbstones.
- Operating the unit is very easy. To switch the device on or off, there is a button on the handlebar with a thumb wheel next to it for adjusting the forward drive to any position as required. This has an automatic reset. The control switches can be placed on the left or right to suit the user.
- The battery pack is charged via a plug on the handlebar. To check battery life, there is a simple green-amber-red LED. The operating time is between 2 and 4 hours, depending on the terrain, and it takes between 3 and 6 hours to charge the battery.
The new walking frame constitutes an important diversification strategy for Reiser, which until now has concentrated on premium-quality machine assemblies. The firm has also started with serial production and the system patent is pending. The co-development was also a good example of the kind of project that would fall under new Industry 5.0 strategies: Simplification of functions has resulted in the most simple technology possible, simple operation, and low production costs.
Prof. Karl Schekulin is director of the Steinbeis Transfer Center for Process Development. The services provided by the Steinbeis Enterprise range from technological crisis management to consulting and innovation support, applied research and development, systematic design in product development, and the design and testing of prototypes. In 2016, Karl Schekulin was awarded the Steinbeis Foundation Transfer Award – The Löhn Award for his contributions as a member of the Steinbeis network toward knowledge and technology transfer.
Reiser AG Maschinenbau (Veringenstadt)