**5.1 Cambered rear wheels concept**

*Public Health in Developing Countries - Challenges and Opportunities*

Push-bar outfitted gadget permits structures that allow people of varying physical strength to move the wheelchair along a wide scope of landscapes, including delicately tricky terrain. The push-bar enable the users to initiate mobility without hand to wheel system. The unique design drives the chair forward with a forward movement of the drive bars while pulling back on the push-bars effects the braking mechanism. Turning is accomplished with a forward movement on one push-bar and a backward movement on the other push-bar. The off-road seat of this design offers the operator a multi-speed equipped favorable advantage over traditional wheelchairs. Changing into lower gears for very adverse terrain such as sandy environment, gives the operators the opportunity to go where they have not had the option to go with conventional wheelchairs. Just changing into higher gears considers allows for movement on pavement and other hard surfaces. The push-bars are removable and may consequently be put away with so that the wheelchair might be moved utilizing traditional hand-to-wheel pushing [20]. This component enables the user to deal with a wide range of landscapes and conditions that are normally restrictive to operators of ordinary wheelchairs and power wheelchairs to be used particularly in open air situations and elements for example forest floors, uneven and harsh terrain. Further, it very well may be utilized to conquer numerous every day snags, for example, curbs and high thresholds [21]. It is advantageous for people with less upper body and arm strength. Accordingly, it accommodates more independent participation in open air exercises, such as hunting, chasing, and so forth. The review above points toward one thing that current rough terrain wheelchairs do not provide total stability ("not ideal"). Thus, there is still a need to come up with a wheelchair that will prevent the user either toppling backward, forward or sideways.

The design development process entailed coming up with a design that improves

The researchers carried out a study on current wheelchair powering methods as well as noting their efficiencies. Power transmission mechanism was fundamental in achieving speed and power. Some engagement with different disability organiza-

The generated design concepts were evaluated and analyzed for suitability for adoption. The chosen concept was further developed to come up with dimensions of the wheelchair, sizing of the wheelchair parts, material selection and detailed drawing of the final design. The detailed drawings were drawn using AutoCAD (2007) and Autodesk Inventor (2017) was used to simulate the strength of the wheelchair frame. The bill of materials was drawn up and the cost estimate and the feasibility of fabricating the prototype unit in the local workshop were done.

The concepts were formulated based on the ability of the design to meet the objective criteria which were: reliability, maintainability, efficiency, robustness,

the wheelchair stability mechanism, safety precautions as well as reduce powering requirements. Some investigations were done on existing all-terrain stability mechanisms, including the possibility of redesigning the wheels and adjusting the center of gravity for improved stability. The safety of the operator, the machine and influence to the nearby environment were considered among other key parameters. Some effort was made to ensure that the final framework of the wheelchair would

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**4. Materials and methods**

address the issues of user safety.

**5. Design concept generation**

tions was done to acquire first hand expectations of users.

The wheelchair is operated like a normal conventional wheelchair, by pushing the wheels forward. Sideways stability is affected by wheelchair width (**Figure 5**). The rear wheels are tilted inwards to increase the base width thus stabilizing the chair. A back-caster wheel is fitted to prevent the wheelchair from falling backwards.

The further out to the side of the wheelchair base, the more the chair l resists tipping over sideways. The camber pushes the wheels nearer to the wheelchair user and more in accordance with the operator's forward push stroke, therefore making it simpler to push. This can be particularly useful for ladies, who normally have smaller shoulders yet more extensive hips than men. Additionally, with cambering, traction is improved when navigating slopes. The wheelchair provides more stability, comfortable seating and it is better for overweight people. On the other hand, a wide wheelchair is more difficult to get through narrow pathways as camber increases the width of the wheelchair. Most anti-tip designs restrict the wheelchair's ability to travel over uneven surfaces (such as kerbs or dips). It is also hard to push.
