This paper aims to tackle the problem of wheelchair bound personnel being unable to climb footpaths due to the absence of ramps on many pavements. The paper suggests a mechanical solution the problem that is simple yet effective in that it allows a wheelchair user to independently climb footpaths with minimal or no assistance. The design, which can be mounted onto any standard wheelchair, uses retractable control rods and an inbuilt ramp to lay an inclined plane in front of the wheelchair when needed, allowing the handicapped person to ascend or descend a step. This paper delineates the function and construction of each component of the proposed system and illustrates the same using both line diagrams and three dimensional computer generated models. It also investigates the various materials available for the construction of the device, whilst stating safety requirements and ensuring that the design adheres to them. Finally, it ends by describing the mode of operation of the device, and possibilities for future development of the design

1. http://www.iaeme.com/IJMET/index.asp 187 editor@iaeme.com
International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 06, June 2019, pp. 187-193, Article ID: IJMET_10_06_013
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=6
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication
MECHANICAL RAMP ATTACHMENT FOR
WHEELCHAIRS TO CLIMB FOOTPATHS AND
ELEVATED SURFACES
Aman Ladia
Liquid Protocol, Mumbai, India
ABSTRACT
This paper aims to tackle the problem of wheelchair bound personnel being unable
to climb footpaths due to the absence of ramps on many pavements. The paper
suggests a mechanical solution the problem that is simple yet effective in that it allows
a wheelchair user to independently climb footpaths with minimal or no assistance. The
design, which can be mounted onto any standard wheelchair, uses retractable control
rods and an inbuilt ramp to lay an inclined plane in front of the wheelchair when
needed, allowing the handicapped person to ascend or descend a step. This paper
delineates the function and construction of each component of the proposed system
and illustrates the same using both line diagrams and three dimensional computer
generated models. It also investigates the various materials available for the
construction of the device, whilst stating safety requirements and ensuring that the
design adheres to them. Finally, it ends by describing the mode of operation of the
device, and possibilities for future development of the design.
Key words: Adaptable ramp, retractable plane, modular wheelchair
Cite this Article: Aman Ladia, Mechanical Ramp Attachment for Wheelchairs to
Climb Footpaths and Elevated Surfaces. International Journal of Mechanical
Engineering and Technology 10(6), 2019, pp. 187-193.
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=6
1. INTRODUCTION
According to the World Health Organisation (WHO) Fact sheet on wheelchairs, about 650
million people or 10% of the world’s population suffer from some form of disability. Out of
this pool, a further 10% are estimated to require a wheelchair [1]. Wheelchairs greatly help
improve the mobility of people with motor disabilities as they provide a method for them to
move around independently or with the help of an assistant.
Unfortunately, there is a wide disparity when it comes to the construction of wheelchair
friendly spaces and infrastructure across the world. This often results in wheelchair-bound
personnel being dependent on a helper in order to commute in their day to day lives. An
example of this is to do with footpaths; while in some countries footpaths have frequently
placed ramps for wheelchairs to use, in others such ramps are nearly non-existent. For
example, consider Mumbai, the financial capital of India. The city is often accused of being

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wheelchair unfriendly as it lacks even basic amenities like ramps for wheelchair users [2].
This reality exists not only in Mumbai, but in many towns and cities of the developing world.
This has a direct implication on the independence of wheelchair users. The handicapped
are forced to either stay at home, or ask for the constant assistance of passers-by in order to
climb or descend footpaths. Not only is this an inconvenience, but also a safety hazard as
lifting a wheelchair several inches in order to push it up a footpath’s edge can result in the
wheelchair toppling and the handicapped person suffering injuries.
2. PROBLEM STATEMENT
Ideally, wheelchair users should be able to access footpaths and steps through permanent
inclined planes. This would allow them to commute freely from one place to another without
the assistance of others and the risk of injury. However, the absence of permanent ramps at
footpaths means that this is not possible, and handicapped people feel all the more immobile.
Therefore, what is needed is a mechanism that allows wheelchairs to climb up footpaths in
the absence of permanent ramps and without external help. At the same time, the designed
system should be universally adaptable to accommodate the different form factors of
wheelchairs available. This paper aims to delineate the construction and testing of such a
system, built entirely using mechanical components and designed to be completely self-
sufficient.
3. DESIGN
3.1. Analysis of wheelchair construction
Before designing the system according to the requirements mentioned in Section 2, it is
imperative to understand the basic construction and operation mechanism of wheelchairs.
Most wheelchairs have the same chassis. It consists of two large rear wheels mounted on a
metal frame, with two smaller front castor wheels below a foot rest. Wheelchairs also
typically have hand rims installed on the rear wheels, which allow the user to drive the chair
without external help. Handles are also provided at the back of the chair in case an assistant is
to help wheel the person. Fig. 1 indicates these components on a typical wheelchair [3].
Figure 1 A typical hand driven wheelchair with annotated components

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From the diagram, it is apparent that wheelchairs are complex mechanical machines, and
any solution that is designed must accommodate for the limited space available. With most
manual wheelchairs weighing between 15 and 18 kg [4], it is also essential that the designed
system be light weight in order to ensure that the wheelchair user is not burdened by the extra
weight of the system.
To this end, it can be seen that there are two major locations within the wheelchair chassis
where a system can be attached. The first location is along the armrests. Wheelchairs typically
have the armrests mounted a few centimetres above the hand rims, with the outer edge of the
armrest aligned with the inner edge of the rear wheels. As a result, there is space to place an
attachment parallel to arm rest above the wheel. The second potential location lies below the
undercarriage of the wheelchair. There is space to accommodate a device below the seat,
attached to the tipping levers (annotation 14 in Fig. 1) or the crossbars (annotation 15).
Placing the system here could allow for usage of unutilized space, but the design would have
to be carefully fitted in order to ensure that there is no obstruction to the movement or
functionality of the wheelchair.
3.2. Construction Overview
The implementation suggested in this paper consists of a carry-on ramp attachment that stays
attached to wheelchairs and uses a mechanism (Fig. 2) to deploy an inclined plane in front of
the wheelchair, thus creating a sloped surface between the road and the pavement. It consists
of the following primary components:
 Mini Ramps: The mechanism uses two ramps as inclined planes that facilitate movement of
the wheelchair from the ground to the footpath. During normal operation, these ramps
resemble footrests, and lie hidden below the wheelchairs existing footrests. When the
wheelchair user wishes to deploy the ramp, the control rods (explained next) bring them to the
ground level.
 Control Rods: The control rods are long aluminium rods that are connected to the mini ramps
on one end and are free for the person to move at the other. They pass diagonally through the
swivel joint and are free to move horizontally along the connector rails. The rods are held in
one place by locks, but are free to slide vertically during ramp deployment (Section 4).
 Connector Rails: Connector rails are attached the handle rails and act as the movement surface
for the control rods which are mounted on the swivel joints. There is one connector rail on
each side of the wheelchair.
 Swivel Joints: Swivel joints allow for complete movement of control rods, horizontally and
vertically, along the connector rails. They also contain locking mechanisms to allow control
rods to remain locked when not used. (Fig. 3)
Figure 2 Side view line diagram of proposed mechanism

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The Swivel Joints features a 360° swivel, free horizontal movement along connector rails
as well as a pass-through hole for the control rods. The arrows indicate possible movements
Figure 3 Swivel Mechanism
To illustrate the functionality of each component in terms of its mobility, a 3D render of
this design was created that shows each part’s axes of rotation and movement.
Figure 4 3D Render of Mechanism with arrows to indicate allowed movements
3.3. Construction Choices
3.3.1. Weight Considerations
The construction of the wheelchair attachment had to be such that the weight of the
wheelchair was increased by only a marginal amount, and yet the strength of the structure was
not compromised. Taking these requirements into account and considering the usual material
choices for wheelchairs, three materials were narrowed down to: aluminium [5], steel [6] and
titanium [7].
Table 1 Densities of various materials considered for attachment
Material Density/ gcm-3
Tensile Yield/ MPa
6061-T6 Aluminium Alloy 2.70 276
Ti-6Al-4V Grade 5 Titanium Alloy 4.42 1100
High Strength Low Alloy Steel (HSLA) 7.90 300
All three materials are used in industrial applications for high load applications (6061-T6
and Ti-6A1-4V are used for aircrafts, while HSLA is commonly used in heavy machinery).
As can be seen, HSLA has a density far higher than both Aluminium and Titanium, which a
marginal difference in strength compared to 6061-T6. When comparing 6061-T6 and Ti-6A1-

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4V, it is clear that the Titanium alloy has a far greater Tensile Yield Strength, but it also has a
higher density. Such a high tensile strength is not needed for a wheelchair design, as the load
carried by the attachment is fairly small (typical weight of the wheelchair and the adult user is
about 800N). Therefore, looking at the high cost of Titanium relative to Aluminium, it was
decided to use Aluminium Alloy 6061-T6 for the construction of the mechanism.
3.3.2. Construction Dimensions
According to the US Americans with Disabilities Act (ADA), the design standards for
wheelchairs prescribe a width of 107 cm for adult wheelchairs, measured from the rear end of
the armrest to the tip of the footrest. The height of the armrest should be 76 cm above the
ground, and that of the handrails should be 92 cm [8]. Hence, through 3D modelling
calculations, it was concluded that the length of the connector rail should be approximately
110 cm and that of the control rod about 150 cm. The width of the rail should be
approximately 5 cm (with a 3 cm cavity and 1cm padding for the walls of the rail) and the
diameter of the control rod around 2 cm.
To decide on the length of the mini ramp attached to the wheelchair mechanism, a review
of footpath and wheelchair regulations was needed. According to the Institute for
Transportation & Development Policy, the footpath should have a minimum width of 1.8 m
and should be at a height of not more than 150 mm from the carriageway. While 150mm is
considered the upper limit for footpaths, in practice, most are designed to be around 100mm
or 10cm above the tarmac surface. Therefore, a ramp of around 10cm height is needed cover
the height of the footpath. The International Residential Code (IRC) suggests a base to height
ratio of 1:10, which means for a ramp of 10cm height, a 100cm ramp length is required. Using
trigonometry, a ramp length of about 100.50 cm is needed, with a width of approximately 2
cm.
3.3.3. Ramp Carpeting
The ADA Standard prescribes a minimum of 0.8 COF (Coefficient of Friction) for inclined
ramps. The Static COF of rubber wheels on Rubber Friction Mats is 1.16, meaning the
aluminium ramp can be covered with a rubber friction mat for good traction.
4. OPERATION
The wheelchair attachment was designed such that the operation is intuitive and easy for the
wheelchair user. The following is the procedure to climb up a footpath using the mechanical
ramp attachment delineated in this paper:
 The handicapped person arrives at a pavement they wish to climb [9].
 They unlock the swivel joints (and therefore the control rods) by flipping the plastic locks on
each side open.
 To deploy the ramp, they push the control rods and align the ramps with the step.
 They now roll the hind wheels of the wheelchair over the ramps and climb onto the footpath.
As they do so, the control rod slips back along the connector rail (Fig. 6) [10]
 Once the wheelchair is completely on the footpath (Fig. 7) [11], they rotate the control rods to
flip the direction of the mini ramps. They then pull the rods back to the front of the
wheelchair, pulling the ramps along.
 They adjust the rods until the ramps are flush under the foot rests. Then they lock the swivel
joints.
With these six steps, the wheelchair user can ascend and descend steps with ease. The
steps for this procedure can be seen in Fig. 5, 6 and 7.

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Figure 5 3D Computer Aided Design (CAD)
Rendering of Wheelchair with Attachment
Figure 6 CAD Demonstration of Wheelchair
climbing pavement
Figure 7 Final CAD rendering of wheelchair on top of pavement
5. CONCLUSION
This paper discussed the construction and operation of a lightweight, easy to use wheelchair
attachment that can allow handicapped personnel to climb pavements without the assistance
of an external helper. The system is built to be cheap, effective and modular such that it can
be installed onto most manually operated wheelchairs.
The paper looked at the design of typical manual wheelchairs, and identified potential
places where a mechanical attachment could be added to allow independent movement of a
wheelchair on footpaths. Two locations were identified, and it was decided that the safest
location would be along the armrests of the wheelchair. Following this, a basic line diagram
was developed that illustrated the construction of the attachment and explained the various
components of the proposed mechanism. To aid in the understanding of the modes of
operation, a 3D model was also supplied.
To extend the discussion beyond the basic design of the wheelchair, three materials were
investigated for suitability. After evaluating the trade-off between cost, density and tensile
strength, 6061-T6 Aluminium Alloy was chosen as the material of choice. Furthermore, it was
decided that the ramp would be carpeted with non-slip rubber in order to conform to safety

7. Mechanical Ramp Attachment for Wheelchairs to Climb Footpaths and Elevated Surfaces
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requirements and ensure that the wheels of the wheelchair do not slip. Dimensions of various
components were calculated and made to fit with safety norms.
Lastly, the mode of operation of the device was explained, and the ease of operability of
the device was made evident. For future development of this device, further investigation into
material choices and joint designs can be undertaken. Adding mechanical features that
reduces the force required to wheel the wheelchair over the ramp (for example, adding a
foldable ramp of larger length that reduces the angle of elevation) can help improve the
usability of this design further.
REFERENCES
[1] Fact Sheet on Wheelchairs. WHO, 2010, Fact Sheet on Wheelchairs,
www.searo.who.int/entity/disabilities_injury_rehabilitation/wheelchair_factsheet.pdf.
[2] Jindal, Sminu. “Mumbai is no city for disabled people.” Mid-day, 28 Jan. 2017.
[3] Dudgeon, Brian J, et al. “Wheelchair Selection.” Occupational Therapy for Physical
Dysfunction, 7th Ed, Jan. 2014, pp. 495–579.
[4] “How Much Does a Manual Wheelchair Weigh?” Karman Healthcare,
www.karmanhealthcare.com/how-much-does-a-manual-wheelchair-weigh/.
[5] “6061 Aluminum: Datasheet.” Gabrian, 12 Feb. 2019, www.gabrian.com/6061-aluminum-
properties/.
[6] Titanium Industry Inc. “Titanium Alloys - Ti6Al4V Grade 5.” AZoM.com, 1 Aug. 2017,
www.azom.com/article.aspx?ArticleID=1547.
[7] “HSLA Steel Datasheet.” MakeItFrom.com, 10 Jan. 2019,
www.makeitfrom.com/material-properties/ASTM-A242-HSLA-Steel.
[8] United States, Congress, Americans with Disabilities Act.
[9] Ladia, Aman. “Wheelchair Ramp Attachment.” 12 June 2019.
https://www.tinkercad.com/things/hHFRs79KyOu
[10] Ladia, Aman. “Wheelchair on Ramp.” 12 June 2019.
https://www.tinkercad.com/things/0kZGa8vlLdE
[11] Ladia, Aman. “Wheelchair on Pavement.” 12 June 2019.
https://www.tinkercad.com/things/3nLlJ5j3w0D