The document describes a student's design project to create a cargo carrier that can be accessed from all three sides. The student presents three conceptual designs before selecting a detachable ramp assembly design with one temporary ramp. The summary design includes a base piece, side gates, claw attachments, and two-part ramp that can be assembled and stored underneath. The design meets or exceeds all requirements around dimensions, height limits, ramp angle, and single-person operation. The student concludes by noting areas for further improvement and the need to select materials and tolerances for manufacturing.

1. Alex Larcheveque | ME 009 (Section 025) | May 24, 2015
Universal Cargo Carrier

2. PAGE 1
Introduction
In class we were assigned to design a new cargo carrier, used commonly for wheelchairs and other
mobility carts. The problem with today’s cargo carrier is that it can only be accessed from one side.
So if there is an obstruction from that one side, the person loading the wheelchair/mobility cart
will have a hard time loading the device. In order to avoid these inconveniences, we will try to
design a cargo carrier that can be accessed from all three sides.
Problem Definition
Create a cargo carrier that can be accessed from all three sides.
The newly designed cargo carrier should follow these design criteria:
 The platform should be 60 x 30 inches. The minimum ramp width shall be 24 inches.
 Max height with cargo: 30 inches
 Max height without cargo: 8 inches
 Ramp angle should not exceed 20° when platform is 18 inches off ground
 Deployed/stored by single person

3. PAGE 2
Conceptual Designs
Design 1: Foldable Design

4. PAGE 3
Design 2: Cargo Carrier with Lift

5. PAGE 4
Design 3: Detachable Ramp Assembly with One Temporary Ramp

6. PAGE 5
Design Concept Selection
From the decision matrix below, I decided to choose the Detachable Ramp Assembly with One
Temporary Ramp.

7. PAGE 6
Embodiment Design
As seen in the title page, this was the final design for the cargo carrier.
In the following pages, I will go through each individual part of the assembly and explain what its
function was. In addition, I will show you how I met and exceeded the requirements for this design
project.

8. PAGE 7
Part 1: Base Piece
The base piece is the main part for the design.
Unique Design Features:
 Hole cutouts that are inserts for the side gates.
 Shafts run across three out of the four sides. The purpose for these are so that they can
attach to the clamps, and will create a temporary ramp. I did not include a shaft for the last
side, because that side would be facing the car’s rear.
 The platform also includes an underbody, in which the temporary ramp can be stored
Requirements Met
 The platform is 60 inches by 30 inches

9. PAGE 8
Part 2: Side Gates
These parts ensures that the cargo inside will not fall out.
Unique Features:
 Designed with correct length so nothing will fall out
 Have tight tolerances (see engineering drawing for tolerances). This allows them to be
taken out/inserted only when force is used. Think of our design as Legos, but for a different
purpose.
Requirements Met:
 Max height with cargo: 30 inches
 Max height without cargo: 8 inches
My design actually exceeds these expectations. In total, our height will be 6.17 inches all the time
(not including the underbody).
Long Side
Short Side

10. PAGE 9
Part 3: Claw Attachment
This part creates a temporary attachment to the shafts on the base piece.
Unique Features:
 The cylinder is not fully closed. This allows for easy attachment/removal to the shaft.
 The circular hole on the rear side of the claw allows for a shaft connected to the ramp to
attach easily.
Requirements Met:
 None

11. PAGE 10
Part 5: Claw Shaft
This part connects the claw and the ramp together.
Unique Features:
 None. It’s a shaft….
Requirements Met:
 None.

12. PAGE 11
Part 6: Ramp (Part 1)
This ramp will connect to the claw and another ramp. These two half ramps will assemble into
one, and are designed to both store in the underbody.
Unique Features:
 Holes inserts are seen on both sides for shafts to fit.
Requirements Met:
 Width is 24 inches
 Ramp angle should not exceed 20° when platform is 18 inches off ground
My design exceeds the requirements of creating the maximum ramp angle of 20°. The total length
of the ramp is 61.20 inches, which creates a 17.10° angle when 18 inches off the ground.

13. PAGE 12
Part 7: Ramp (Part 2)
This ramp will touch the ground. On the other end, it will connect to ramp (part 1) through a shaft.
Unique Features:
 Hole inserts on one side of the ramp for shafts to fit.
Requirements:
 Same requirements as Ramp (Part 1)
Side will touch the floor

14. PAGE 13
Part 8: Ramp Shaft
This part connects ramp (part 1) to ramp (part 2).
Unique Features:
 Again, it’s a shaft….
Requirements Met:
 None.

15. PAGE 14
Summary/Conclusions/Recommendations
SUMMARY
All in all, I thought that my cargo carrier was successful. It fulfilled, even exceeded, all the
requirements specified and solved the problem: Build a cargo carrier that can be accessed from all
three sides.
There were five requirements I needed to fulfill for my design. They were 1. Dimensions of
platform (60” x 30”) and ramp width (24”) 2. Max height with cargo should not exceed 30” 3. Max
height without cargo should not exceed 8” 4. Ramp angle should not exceed 20 degrees when 18
inches off the ground 5. The ramp should be able to be deployed/stored by a single person.
For the first requirement, I followed exactly what the dimensions stated. I made my
platform 60” x 30” in the sketch, and the same went for the ramp width. The second and third
requirement are always fulfilled, because my maximum height of the cargo carrier is fixed at 6.17”.
My height calculation for the cargo carrier height does not include the underbody storage. This is
because the connection of the cargo carrier and the tailgate of a car would not start at the
underbody, the connection would be placed above the underbody of the cargo carrier. The fourth
requirement is fulfilled by using single trigonometry to find the minimum length my ramp needs to
be. Through sin(20)=(18/x), x needs to be at least 52.62” long. My ramp was 61.20”, creating a more
convenient 17.10 degree angle with the ground. My last requirement is fulfilled by using a Lego-
inspired design. Everything can be attached and taken off using shafts and insert holes.
FTERWARDS
This is not my final design. I would still have to do a few steps after this design to ensure
that my product is ready to be sold. The following are what procedures I would follow after this
project.
First, I would make a few more improvements to my design. One area that I believe needed
the most work done to it were the side gate. I think that my side gates design could have been more
permanent than just being held in by tolerances. Maybe a gate swing out design, with one hole
insert being permanent and the hole free swinging, would have made the gate more ergonomic and
permanent.
Second, I would have to choose what material to make the cargo carrier out of. This
material would need to be strong, because a wheelchair/mobility cart sitting on top of the cargo
carrier would weigh close to 100 pounds. I was curious to see how much stress my bottom piece
could hold, so ran a stress test. I used alloy steel for the material and used 50 psi of force applied to
the top face of the part. The results did were not as good as I expected. I either need to have a
stronger material to use, or I need to make structural supports to increase the integrity of the part.
Lastly, I would make sure I liked the final design. I would then create detailed designs and
choose what tolerances I would use for a manufacturer. The manufacture would make the part, we
would be sold in stores all over the world, and we will see all that money roll in.