College of Engineering Technology and Computer Science Department of civil & Environmental Engineering MEEN 3210 – MECHANISM DESIGN Dr. L. Onyebueke Project #1 Group Member 1: Chinonso Chimezie Group Member 2: Mohammed Alghamdi Group Member 3: Said Alamri Group Member 4: Donald Toohey Date Submitted: 10/14/15 Term: Fall 2015 Table of Contents Cover Page 1 Table of Contents 2 Introduction 2 Explanations of Design Decisions 2 Problem-Solving Methodology, Methods of Analysis, and Synthesis 3 Engineering Principles used in the Design 7 Failure Theories and Design Criteria, Design Equations and Sample Calculation 7 Safety Aspects of the Project and the Designer’s Response to Potential Safety Problems 8 Creative thinking; Decision Making 9 Optimization 10 Computer Simulation 11 Identification of Group Work and Individual Work 14 Discussion and Interpretation of results 14 References 15 Introduction In this report, an analysis of a construction lift is presented along with a discussion of potential safety aspects and the interpretation of results. Construction lifts are an important product on construction sites. It makes it easier to transport bricks from one floor to another thus increasing the efficiency for construction cost and labor. The designs of these types of lifts are crucial for the safety of operation. The important part of the design of this lift is to design the motion for the carriage of the lift. In this report, the technical specifications of lift are provided. In subsequent sections analysis of the lift design is carried out and then discussion about the safety of lift is presented. Explanations of Design Decisions The feasibility study of our project was based on a four bar linkage and six-bar quick return linkage mechanisms. The four-bar linkage is the simplest pin jointed mechanism for single degree of freedom controlled motion. It could generate many different motion depends on the links length, and it is the most common device used in machinery. Whereas the six bar mechanism is more complex mechanism and needed for a difference in average velocity between their forward and return strokes. The decision of choosing a design was made in order to include what has been studied in this course. Therefore, four bar linkages and a six bar quick return mechanism was chosen to have a mechanism that could make a full revolution and transport a body 90 degrees. After a careful consideration the group members have finally decided to design a mechanism to handle brick transport. It was difficult at first to choose a design since everyone liked different design, so each member in the group asked to sketch their desire design and the best one was selected. Problem-Solving Methodology, Methods of Analysis, and Synthesis Initially the analysis of the problem revealed that the bricks not only transferred from one belt to the next but that these belts were perpendicular and had a vertical difference of one ...

1. College of Engineering Technology and Computer Science
Department of civil & Environmental Engineering
MEEN 3210 – MECHANISM DESIGN
Dr. L. Onyebueke
Project #1
Group Member 1: Chinonso Chimezie
Group Member 2: Mohammed Alghamdi
Group Member 3: Said Alamri
Group Member 4: Donald Toohey

2. Date Submitted: 10/14/15
Term: Fall 2015
Table of Contents
Cover Page 1
Table of Contents 2
Introduction 2
Explanations of Design Decisions 2
Problem-Solving Methodology, Methods of Analysis, and
Synthesis 3
Engineering Principles used in the Design 7
Failure Theories and Design Criteria, Design Equations and
Sample Calculation 7
Safety Aspects of the Project and the Designer’s Response to
Potential Safety Problems 8
Creative thinking; Decision Making 9
Optimization 10
Computer Simulation 11
Identification of Group Work and Individual Work 14
Discussion and Interpretation of results 14
References 15
Introduction
In this report, an analysis of a construction lift is presented
along with a discussion of potential safety aspects and the
interpretation of results. Construction lifts are an important
product on construction sites. It makes it easier to transport
bricks from one floor to another thus increasing the efficiency
for construction cost and labor. The designs of these types of
lifts are crucial for the safety of operation. The important part

3. of the design of this lift is to design the motion for the carriage
of the lift.
In this report, the technical specifications of lift are provided.
In subsequent sections analysis of the lift design is carried out
and then discussion about the safety of lift is presented.
Explanations of Design Decisions
The feasibility study of our project was based on a four bar
linkage and six-bar quick return linkage mechanisms. The four-
bar linkage is the simplest pin jointed mechanism for single
degree of freedom controlled motion. It could generate many
different motion depends on the links length, and it is the most
common device used in machinery. Whereas the six bar
mechanism is more complex mechanism and needed for a
difference in average velocity between their forward and return
strokes.
The decision of choosing a design was made in order to include
what has been studied in this course. Therefore, four bar
linkages and a six bar quick return mechanism was chosen to
have a mechanism that could make a full revolution and
transport a body 90 degrees. After a careful consideration the
group members have finally decided to design a mechanism to
handle brick transport. It was difficult at first to choose a
design since everyone liked different design, so each member in
the group asked to sketch their desire design and the best one
was selected.
Problem-Solving Methodology, Methods of Analysis, and
Synthesis
Initially the analysis of the problem revealed that the bricks not
only transferred from one belt to the next but that these belts
were perpendicular and had a vertical difference of one meter.

4. After the establishment of what motion was needed, research on
existing systems lead to several robotic forms. However, it was
decided that these robots did not meet the criteria for the
design.
In designing the mechanisms, position synthesis was used to
create a direction and size of motion from the starting position
to the final position. The geometric positioning of the bricks
were set in a horizontal tray and lowered along the vertical
plane. Then they were rotated on a horizontal plane so that the
bricks would be positioned such that the longitudinal axis of the
brick continued to stay perpendicular to the direction of the
next conveyor belt motion. Finally the bricks are transferred to
the next conveyor belt by ejecting them onto the belt.
The vertical belt was design as a quick return linkage so that the
downward motion was slower than the return motion, shown in
Figure 1. This motion was intentionally designed so that the
bricks would stay in a continuous downward assisted motion
versus allowing them to fall. The brick were to be stabilized so
that when transferred to the next tray it is at a slower motion so
that the bricks do not bounce off the tray they are being
transferred to.
Figure 1 - Vertical Synthesis
The vertical distance from top of the first belt to top of the
second belt was designed at one meter. However, the vertical
distance the tray moves was increased to 44” so that the tray
could continue to move down and out of the way so that the
horizontal tray could catch the brick and rotate. When the brick
lands on the middle tray the motor for the horizontal tray is
turned on for a brief second and stops momentarily so that the
next tray can pick up the brick, then the horizontal motor is
again engaged so that the tray returns home. The last

5. mechanism is also on a time delay and will continue to run until
it returns to the home position. This mechanism does not hold
the brick which allows the brick to be ejected onto the next belt.
Another reason the distance was increased was so that when the
brick is lifted off the second tray the brick is ejected with a low
elevation above the last belt. Both link syntheses were
completed at the same time because they are simply a four bar
linkage mechanism, shown in Figure 2.
Figure 2 - Horizontal Transport and Vertical Lift
The calculations used are shown in the figures above but are
placed here below to show mathematical formulas and values
used
Mechanism 1
The vertical tray must be a preloaded structure so that the tray
stay horizontal to the ground, therefore DOF =0
L= 7 J1=9 J0=0
Vertical tray must move a minimum of 44”
Link 4 and 2 are grounded perpendicular to the movement of the
tray.
Link 4 = 44”/2 = 22”
Link 1 = 6” (distance between ground link 4 and 2)
Time Ratio 1:2
To get the link to travel slowly down and quickly return, set the
inside angle such that it is 240°, by finding an angle 45° off the

6. direction of movement and then offsetting or dividing the 120°
evenly across the new angle. Therefore to find the angle setting
for the motion set the angle to the left of the direction of motion
and the find the time ratio with respect to 180°.
If , then
This means that will be to the right on the direction of the
rotary motion and the opposite angle for this is
To find Link 2 and 3, if Link 3 = c, Link 2 = b, and therefore
because Link 1 = 6” and Link 4 = 22”
Mechanism 2 & 3
These are both four bar links with a time ratio of 1:1, DOF = 1,
and Link 4 needs to rotate 90°.
L= 4 J1=4
If Link 3 = 6.5
Link 4 =

7. If Link 2 = 3.5”
Link 1
Link 1 = 7.492”
Engineering Principles used in the Design
The engineering principle of this mechanism design is to design
a mechanism to handle brick transport. In another word, a
mechanism to pick up bricks from a moving transport belt and
transfer them onto another belt moving at 90 degrees. In this
design, we used a simple engineering principle of the basic
knowledge for mechanical and engineering design. In order for
us to achieve and design a mechanism that functions as we want
it to, some calculations and rules needed to be followed. Three
mechanisms needed to transport bricks from one belt to another
belt, using Grashof conditions to build two four-bar linkage, for
the four bar linkage to make a full revolution case (I) has to be
followed , which states that shortest link (S) plus longest link
(L) must be less than the sum of the other two links (P & Q).
The other mechanism is six-bar quick-return linkage. In the six-
bar quick return mechanism angels α and β needed to be
determined using the time ratio 1:2 and the equations are as
followed:
Moreover, the degree of freedom (DOF), is equal to the number
of independent parameters needed to uniquely define its
position in space, was found using the links and joints that were

8. calculated in the calculation section.
Failure Theories and Design Criteria, Design Equations and
Sample Calculation
One of the most perplexing problems we faced during with this
project was the selection of design and develop a reboot design
to withstand failure. We all came to a decision of choosing the
brick transport as our topic for this project. To predict or
estimate the mechanical failure and yield of machine parts and
structural members we analyzed our design of the brick
transport with the failure theories. The mechanical failures of
the structural components in our design will be associated with
excessive flexibility of our materials, which are the limitation
in stress and strains of the materials over a period of time.
Because our design incorporates motion and syncretized timing,
functional failures become a high probability. A secondary
failure can occur with the failure of some other piece of
equipment. The durability of the joints and links are also
susceptible to failure because of the motion and weight of the
bricks. We identify the mechanism where the bricks lay while
being transported as our area of overdesign and will need to be
modified in the future.
In our concept design of the brick transport, designing a
feasibly transporter to meet the design criteria and requirements
provide to be our biggest challenged. The design criteria is to
design a brick transport that will pick up bricks from a moving
transport belt and deposit them onto another moving at 90°
angle. The speed of the belt is 0.5m/sec with the width at 0.4m.
The brick dimensions are 20 x 10 x 5 cm and weighs 2.5 kg. The
maximum acceleration on the brick is 2g. The bricks lie flat on
the belt with the distance between bricks being 20 cm in the
direction of the motion and 10 cm along the longitudinal axis of
the brick. The vertical distance between the two belts is 1 m.

9. In order to meet our requirement, we incorporated a four bar
linkage with a six bar quick return linkage mechanisms. To
determine the degree of freedom for the four bar linkage,
Gruebler’s equation is used, which is DOF = 3(L – 1) – 2 +
where L is the number links. is the number full joints and is the
number of half joints. Using this equation, we get our DOF to
be two degrees for the entire structure. For the six bar quick
return linkage mechanisms, the rate of change of angular
velocity with respect to time can be determine by using the
equation
The beta angle, β, can also be found with this equation
The following equations below are used to find the retracted,
extended, and F extend.
Since many arrangements of links chosen during our design of
the brick transport will provide the same features, we had to
synthesize the right one. We used two equation where is the
ratio of our design and =. = 1:2. The second equation being α
+ β = 360. This can be incorporated in solving for angles α and
β to give the output stage.
α =
β =
Safety Aspects of the Project and the Designer’s Response to
Potential Safety Problems

10. The safety aspects to be considered for this lift are:
1. From the design perspective, the lift is built for the factor of
safety of five. This makes the lift to take five times of the
ultimate load in an uncertain condition. When the load reaches
above this level, the lift will fail.
2. Construction lift for brick transportation is designed with the
power electronics concept. Such that, when the load reaches the
level beyond the factor of safety, the machine will
automatically shut down because of the connection breakdown
for the belt rotation power supply.
3. The maximum of one pair of bricks can be transferred using
this machine.
4. Operational safety is ensured in a construction lift, by
providing the emergency shutdown controls.
5. The maximum acceleration load considered for the design of
lift is twice the gravitational force. This ensures the safety of
lift during any free fall event scenario.
Technical Specification
In this section the given technical specifications for
construction lift are presented.
Angle between lift belts, θ = 90
Brick transport rate, r = 1 brick/second
Belt speed, v =0.5 m/s
Belt width, b = 0.4 m.
Brick dimensions = 20x10x5 cm
Brick Mass, m = 2.5 kg
Maximum acceleration on the brick, a = 2g
Vertical distance between the two belts, d = 1m
Bricks are oriented with their longitudinal axis perpendicular
with the direction of motion and they lie flat on the belt in pairs
with distance between bricks 20 cm in the direction of motion

11. and 10 cm along the longitudinal axis of the bricks.
Analysis
In this section, the lift design is carried out.
Brick volume, V = 20 x 10 x 5 = 1000 cm3
Weight of brick, W = mg
W = 2.5 x 9.81 = 24.53 N
Acceleration loading on carriage, N = 2g
Total load, P = 24.53 * 2 * 9.81 = 481.27 N
Load for pair of bricks, F = 2P = 2 * 481.27 = 962.54 N
Using the engineering stress theory, the cross section of the
carriage can be designed for material yield stress.
Chosen material for carriage is aluminum.
Stress, σ = F/A
Yield stress of aluminum,
Considering factor of safety, FOS = 5, the allowable limit of
stress can be calculated as
Therefore, the allowable cross section for the carriage, A =
962.54/43 = 23 mm2 . This is the minimum required cross
section for the aluminum carriage to carry the bricks.
Creative Thinking; Decision Making
Various mechanism ideas began with developing a motion that
would pick up the brick and maneuver the brick vertically one
meter. The first design began with a mechanism that would
travel an inverted “J” movement, but as a group the motion
could not be attained with one mechanism using various shapes
of linkages. Next the consideration for a barrel cam was
developed and drawn up. However, the rotational motion of the
parallelogram linkage traveling vertically interfered with the
side of the barrel cam, shown in Figure 3. Then the idea to catch
the brick as it came off the end of the conveyor into a tray was

12. considered but consisted of one tray that had the potential of
dropping the brick before reaching the next belt, shown in
Figure 4. Finally we concluded that the design could consist of
more than one mechanism and that the motion could be create
with three different mechanisms.
Figure 3 - Barrel Cam with Vertical lift
Figure 4 - Vertical Lift
With the thought process to use three different mechanisms, one
mechanism could move the brick vertically, another could rotate
the bricks 90 degrees and the last mechanism could deliver the
bricks to the belt. The first mechanism that transfers the bricks
vertically could be created with a six bar linkage that was set up
with a 2:1 ratio so that the movement would be slower on the
travel downward, then quickly return to the top to retrieve the
next brick. The second and third mechanism are simple four bar
mechanisms with a 1:1 time ratio. The positioning of the trays
would be on a trigger sensor that would turn the power on to the
motors once the brick was set in position.
Optimization
Optimization is the process of maximizing a desired quantity or
minimizing an undesired one. Usually, optimization theory is a
body of mathematics dealing with the properties of maxima and
minima and also showing how to find maxima and minima
numerically. This is supported by the design equations and
simple calculations provided earlier. We used different
optimization methods in search of the best combination of
design models using sets of model to get a clear and desired
outcome. Evolution of past designs was our first attempt to
improve upon existing designs. We encountered trial and error
as we optimized the brick transport, as we recognized that our

13. first feasible design was not necessarily the best. In hopes of
finding an improved design, different design model were
exercised for iterations.
Computer simulation
Figure 5 - Tray Up and Tray down
Figure 6 – Horizontal Motion
Figure 7 - Brick Transfer Exchange
Figure 8 - Brick Ejection
Figure 9 - Return to Home Position
Identification of Group Work an Individual Work
Chinonso Chimeze
Optimization
Failure Theories and Design Criteria, Design Equations
and Sample Calculation
Mohammed Alghamdi
Introduction
Technical Specification

14. Safety Aspects and Analysis
Discussion and Interpretation of Results
Said Alamri
Brainstorming design ideas
Explanation of Design Decision
Engineering Principles
Donald Toohey
Brainstorming design ideas
Drawing mechanisms
Problem-Solving Methodology, Methods of Analysis, and
Synthesis
Creative Thinking; Decision Making
Computer simulation
Discussion and Interpretation of Results
The design of the construction lift is crucial for transporting the
bricks during the construction event. This is a cost effective
method. However safe working conditions are to be ensured,
otherwise it can lead to a catastrophic failure. In this work, the
construction lift is designed for the factor of safety of five. The
lift carriage is designed with aluminum which is a light weight
material having good strength to weight ratio.
The lift carriage area is calculated for an acceleration loading of
twice the gravitational force and the weight of the lift. This is
the minimum strength required for the carriage. The area
provided in the technical specification is higher than the
minimum area and hence the lift carriage is operationally safe.
Thus the design lift is safe for carrying the pair of bricks at the
speed of 0.5m/s.

15. References
Norton, Robert L. Design of Machinery. 5th ed. New York City:
McGraw Hill, 2012. Print.
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