Engineering design specifications

HND Mechanical EngineeringUnit Code : M/601/1475

Victor M. Aguayo Garcia

Engineering design

specifications

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TABLE OF CONTENTS

Task 1 ( P1.1 ) Establish customer requirements …………………………………………………… 3, 4

Task 2 ( P1.2 ) Present the major design parameters ………………………………………………..4, 5

Task 3 ( P1.3 ) Obtain design information and prepare a design specification ………………… 5 - 9

Task 4 ( P1.4 ) Demonstrate that the design specification meets requirements ……………… 10, 11

Task 5 ( P2.1 ) Produce an analysis of possible design solutions …………………………… 11 - 14

Task 6 ( P2.2 ) Produce and evaluate conceptual designs ……………………………………………14

Task 7 ( P2.3 ) Select the optimum design solution ……………………………………………………15

Task 8 ( P2.4 ) Carry out a compliance check ………………………………………………………… 16

Task 9 ( M1 ) Identify and apply strategies to find appropriate solutions …………………………… 17

Task 10 ( M2 ) Select/design and apply appropriate methods/ techniques …………………… 17, 18

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P1)

Problem description:

At present the use of cars is very common among people especially in small towns . The problem is that with the increase in cars, some companies have realised the need for tow trucks to pick up cars breakdowns or flat tires. This is positive , the problem is that these companies charge very high prices. Some users do not have any problem but some drivers often do not have money to carry out the payment. There is also the need for this type of repair in places far removed from workshops, or inaccessible as well as in Asian or African countries where the use of tow trucks are not common.

A survey on the perception of discomfort and difficulties in using the hydraulic jack, which could be identified some deficiencies anthropometric applied. In analysing the activity, it was observed that the person performing the lifting operation of car with the help of a hydraulic jack makes takes great effort and awkward postures which may cause further damage using a conventional hydraulic jack. Damage may be back pain, knee, wrist. The aim is to innovate a mechanical jack through some changes and ergonomic applications, so that the user has the ease and comfort of carrying out the Manoeuvrability to lift a car, and be sure that just activating a control can perform the task without need to use physical force. Virtually anyone who uses car, can see benefit with this ergonomic product. Due to its design and handling, it is easy to use. It tries to reduce physical exertion in people who have to use a jack to self, like avoid injury from poor posture.

The aim is to redesign a functional hydraulic jack for any type of person, that most users do not have problems using it. The improvement consists of an electric automotive hydraulic jack where austerity will be replaced by innovation, functionality is the same as that of a conventional hydraulic jack, but eliminating stress, fatigue and complex use. The automotive electric hydraulic jack use the current of the car. with the push of a button you can perform the necessary Manoeuvrability . Automotive electrical cat can be used by any user of the car, which has previously read the instructions. The car must weigh at most two tons. The current required for the operation is 12 volts , which is compatible with the car battery ( compact cars , sedans ) . Cat redesigning use anthropometry, ergonomic controls for designing principles. He obtained as an electric automotive end redesign cat with improvements in size and manner of performing the operation, but the functionality is the same as a hydraulic jack .

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P1.2)

General objectives:

Elaboration of hydraulic , able to lift up to 2000kg car , safely , easily, effortlessly , it have to be portable also indicated for people with only one arm, or elderly people who can not make great efforts.

For the proper functioning of the hydraulic car jack , the device has to meet certain requirements or parameters as explained below

At this stage I will assess and analyse the design to identify critical areas for improvement and evolution . This section will explain how the parameters and engineering specifications are analysed in order to move to the initial manufacture of the final prototype

Customer Requirement Importance ( 1 low, 5 high )

Engineering specification

Target Value

Safety 5 Safety factor 1.5

Easy to clean 4 Cleaning time (minutes) 5

Longevity 5 Service Lifetime (years) 15

Affordable 5 Manufacturing cost < £50

Robust 5 Upward suport Force (N) > = 19600

Easy to use 4 Easy to understand manual

Deferents languages

Max. weight 4 Lightweight Materials (Kg)

< 10

Size 4 Compact size (cm) 45 * 20 *12

Aesthetic 1 Beautiful design

Ecofriendly 3 Electric power ‘0’ CO2 emissions

12v Input voltage 5 DC12v DC12v

Lift height 5 Extender arm 30 - 45

Use Ratio 4 Cable length (m) > 5

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P1.3)

a)

Pascal's principle is used in operation of hydraulic machines generically called: the press, the cat, the brake, lift and crane, among others. This device, called hydraulic press allows us pressing, lifting applying very small forces. Let's see how. The liquid filled container is made figure two-necked different section, closed with respective caps fitted and capable res-baa freely within the tubes (pistons). If a force (F1) on the small piston is exerted, the pressure exerted is transmitted, as Pascal observed at all points on the fluid within the enclosure and produces forces perpendicular to the walls. In particular, the wall portion represented by the large piston (A2) feel a force (F2) so that while the lower small piston, the largest rises. The pressure on the pistons is the same, but not the force! P1 = p2 (because the internal pressure is the same for all points) Then: F1 / F2 is equal to A1 / A2 so clearing a term we have:. F2 = F1 (A2 / A1) If, for example, the surface of the larger piston is four times that of the small, then the magnitude of the force will be obtained in four times the force exerted on the small.

Parameters resource requirements Risk

Materials Strong Safety

Safety Security Damage

Weight Light Injuries

Robust Strong Life in service

Dimension Small Space

Cost Cheap Budget

Performance Research Safety

Production methods

Mechanisation Budget, Safety

Environmental impact Green CO2 emissions

Legal implications Standards Penalties even prohibition

Transportation Size Space

Economical contraint cheap Budget

Knowledge Research Safety, Performance

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Source: http://hyperphysics.phy-astr.gsu.edu/hbase/fluids/imgflu/hpress.gif

Source: http://hyperphysics.phy-astr.gsu.edu/hbase/imgmec/carl.gif

The diameter of the pistons of my jack will be D1 = 2cm and D2 = 10cm

F2 = 19600 N , that’s because F2 = m * a where mass = 2000kg and acceleration (g) = 9.8 N

9.8 * 2000 = 19600 N

Then F1 = ( A2 / A1 ) * F2

A1 = π * r² = 3.14 * 0.01² = 3.14 * 10-4 m²

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http://hyperphysics.phy-astr.gsu.edu/hbase/fluids/imgflu/hpress.gif

http://hyperphysics.phy-astr.gsu.edu/hbase/imgmec/carl.gif



A2 = π * r² = 3.14 * 0.05² = 0.00785 m²

F2 = ( A2 / A1 ) * F1 there for F1 = F2 / ( A2 / A1 ) where 19600 / ( 0.00785 / 3.14 * 10-4 ) = 784 N

Pressure 1 ( P1 ) = F1 / A1 = 784 / 3.14 * 10-4 = 2496815.28 Pa = P2

this is the pressure inside the system that’s why is extremely important to take this into account in the selection process of the material to ensure that the material could withstand these pressures without compromising the user's safety at risk.

Pressure = 2496815.28 Pa = 2.50 MPa

As we can see in the table even choosing steel with Minimum Yield Strength ksi (MPa) even considering a safety factor of 10 times the required strength is still very safe.

Source: https://www.steeltank.com/Portals/0/pubs/Welded%20Steel%20Pipe%2010.10.07.pdf

B)

Ergonomics:

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https://www.steeltank.com/Portals/0/pubs/Welded%20Steel%20Pipe%2010.10.07.pdf



Is very important to prevent injuries and make it easier to use customer, so I is designed for this purpose

Materials:

the materials used for the device will be steel and plastic in different parts of its structure , to make it strong enough to withstand the pressures that will be placed under , or hard to hold 2000 kg , so it will have plastic parts to make more ergonomic and lightweight

Product life span:

The life span of the product will be extremely high if you give a good use and will not be subjected to extreme environments or situations to be taken to limit above the recommended limits . This may take 20 or 30 years without problems

Legal:

Comply with all applicable laws and standards is the requirement number one, without both of them the The authorities won’t authorized for sale and the customer could not use.

Life in service:

The service life will be a minimum of 10 years for the materials used, as well as its little use because it will be made to non-professional clients.

Product cost:

The product cost will be £ 20

Performance:

The product has to work, and must meet all specifications , if not the customer does not buy that do not comply with the requirements.

Size:

The size of the device is designed in such a way that will allow storage in a plastic case that may be placed on one side of the boot

Shipping:

The device will be sent via boat, road or plane, by region, customer proximity and urgency

Manufacturing facility:

The product is designed in a way that is very easy to machine, and have all 3D designs and has taken into account the type of process needed to minimize cost

Market contains:

Market contains many different types of designs for this function , but this design is more designed for ease of use adapted to people with reduced mobilit , older people, or women who are not strong.

Maintenance:

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The need for careful maintenance is almost none , because it is placed in his briefcase where it is isolated from anything that might spoil , due to low usage , we may consider that the only maintenance required is to change the oil in case It had a leak.

Packing:

The product will come with his briefcase , and this wrapped in a cardboard box filled with extruded porexpan for protection

Environment:

the device will be very respectable with the environment because it does not generate any mark on the environment , alone in his production , but being charged with electric power from the battery of the car, and have all recyclable materials including oil piston may be reused , so we consider it a green product and ecofriendly

Safety:

In the operating instructions for the product will be indicated a number of steps to avoid

any risk as :

-Install the hydraulic jack under a solid and structural part of the vehicle chassis

-Experts recommend using at least two hydraulic jacks of the same height so that the vehicle rests equally on both sides.

-Add objects to increased security . While the jack and wheel chocks give good stability.

All such recommendations will prevent misuse of the car jack , which will prevent any danger to their safety.

Quality reliability:

The product is 100 % reliable , it has passed all the tests that have been submitted , and meets all industry standards so it should be reliable

Weight:

The weight of the car jack will be not more than 5 kg which will make it quite manageable , since one of the priorities of the project is suitable for every type of customer, with different physical characteristics , age , or disability

Politics:

The design complies with all laws and demands from all Govier analyzed, which is why there should be any problems with legal issues.

Disposal:

At the time when the customer wants to get rid of the product , this is ecological , and all parts that contain it are recyclable . so any recycling center may deal

Time scale:

The time it takes to to raise the car is very short since it is an electrical mechanism that exerts a constant force , approximately 10 seconds.

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P1.4)

After reviewing the aspects of the final design with the customer, we concluded that to meet the requirement of the final price , and size of the product, the design had to be less aesthetic and more functional , since the priorities of greater value were the price and size.

P 2.1)

In this task I will explain different designs I had in mind.

This first design was very basic , but it gives a chance to use it even when the battery is discharged , so it can be used manually or using battery power. The design problem is that it is not practical to handle and makes it heavy.

Prototipe 1

In this other design I tried to design a more aesthetic and manageable prototype as you can grab a using a handle . The problem with this design is that you have to carry all the items at once , making it heavier and take up much space

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Prototipe 2

In this design I thought about the possibility of adapting a battery, to avoid having to plug it into the car battery if this is discharged , but that makes more expensive de product than the limit budget required and also makes it heavier.

Prototipe 3

Finally we have another design this time I designed a prototype that is easier to handle. for this I have added wheels to move it without exerting force. also it gives you the ability to use it manually as in the first design in the event that the battery is discharged . Once on the site you can lock the wheels to avoid any hazard.

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Prototipe 4

I also designed a system that allows cables have collected, in which, when we extend the cable we must exert force and to pick it up automatically taken up . It is similar to the mechanism of tape measure. This system collects both cables . The plug adapter 12v and also the control with which we can raise and lower the car jack.

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I finally designed what could be a briefcase to save all parts of the prototype, even you could include an impact wrench. This case allows us to have all the necessary equipment on one side of the trunk without taking up too much space It also allows the handle so easy and safe.

P 2.2)

Selection criteria vs Design proposal

Prototipe 1 Prototipe 2 Prototipe 3 Prototipe 4

Aesthetic - + - E

Ecofriendly + + + +

Weight E - - +

Safety + + + +

Affordable + + _ E

Size + - E +

Selection criteria vs Design proposal

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P 2.3)

Once we finished the matrix table , it is obvious which is the most suitable prototype for development.

The reason why it is the most appropriate design is that the parameters that are included in , are most similar to those required by the customer compared to other designs. These parameters are the following I comment below.

Weight:

Compared to other designs weight in this design it is smaller because some elements can be removed as the element winding cables , do not charge extra weight as the battery , the stick that guides and also allows you to lift the car manually also you can be unscrewed .

Safety:

It is safer than the rest because it will also require physical exertion to take it with you because you can separate the pieces reducing weight , avoiding injuries for older people or with disabilities

Size:

Another aspect that improves the other designs is that being removable , allow me to organize all the elements in a briefcase occupying less space in the trunk.

Easy to use:

Finally it is easier to use thanks to the post that lets you move using the wheels, or the device that automatically collects cables allowing the wires do not tangle and easy to pick up.

Easy to use - + + +

Score 2 3 0 5

Rank order 3 2 4 1

Prototipe 1 Prototipe 2 Prototipe 3 Prototipe 4Selection criteria vs Design proposal

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P 2.4)

Customer Requirement Customer Requirement (Target Value)

Design specification value

Design Verification

Safety 1.5 >10

Easy to clean 5 (minutes) 5

Longevity 15 15

Affordable < £30 £25

Robust > = 19600 19600

Easy to use 10 languages 10

Max. weight < 10 8

Size 45 * 20 *12 35 * 18 *10

Aesthetic Functional design Functional design

Ecofriendly ‘0’ CO2 emissions 0’ CO2 emissions

12v Input voltage DC12v DC12v

Lift height 30 - 45 25 - 43

Use Ratio >= 5 5

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M1)

The first thing I had in mind when designing different prototypes was research, questioning , asking potential users , what are the needs of this type of product, I conducted a survey for it , I asked several questions such as the following:

-It is difficult for you to use the current car jack ? why? -The money would you be willing to pay if it were easier and quicker to use ? -Do you have pain in your back or wrist when you use it ? -How long it takes to change a wheel

After studying the different answers I studied the market trying to adapt some current technologies that I think are very positive for customers need , but I also added new adaptations in order to meet my client’ s requirements and people in general.

The problem was when trying to implement many technologies this product increase much more the cost , so I started with a very basic design and then I gradually was adding new solutions to meet the necessary requirements . It was a long investigation , and much time thinking and asking me questions , about different possibilities to find the best solution.

There was also the problem of the technical aspects , the study of the standards necessary for the possible sale. Studying safety factors , studying the different materials, their specifications , and comparing the features with the necessary parameters as well as studying their costs at the same time. This was very difficult because many materials have perfects features to the product but the price is very high, but others do not meet the legal requirements for this product, so it was a long investigation.

On the other hand I have considered different aspects such as the constrains of different prototypes. One of the design constraints I found in the first prototype was the absence of wheels, so to move it, it had to be carrying the weight of the entire equipment, and that is not practical when the goal is to make it suitable for all types of customer: gender, age, even people with some kind of disability. Again in the second prototype I had the same problematic in the second design attempting to produce a more aesthetic and handy design, it became too bulky, leaving no room for other things in the trunk of the car. In the case of the third design after analysing, I noticed two types of design constraints. The first one was the increased cost of the prototype once you add a battery making more expensive the product than the price required by the customer. The second one, with the addition of the battery the weight of equipment would be even heavier than the first one. Avoiding any chance of portable tool for elderly people or people with back illness. However in the chosen prototype I combined the positive characteristics of previous designs and avoid its constraints, the last prototype gives an opportunity of using it manually if the car battery is discharged, also has wheels that allows move it without having to carry it . Also it can be dismantled for parts allowing in case of clients with little force, due to illness, older or disability not have to get him or out of the trunk of a piece , I also designed a system for this prototype to collect cable automatic form the last prototype gives an opportunity of using it manually if the car battery is discharged, also has wheels that allows its travel without having to carry the . also it can be dismantled for parts allowing in case of clients with little force , due to illness , age or disability not have to get him or out of the trunk of a piece , I also designed a system for this prototype to collect cable automatically.

Finally with all the necessary requirements , the parameters met, and following all standards and security protocols.

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The determining factor in the choice of product, was the indications and customer priorities included in the survey comparing the features and functionality of prototypes with customer requirements I have come to the conclusion that the most suitable product for the customer , the with more positive aspects and less constrains is the last prototype.

M2)

First of all the first thing I did was listen to my client, write down all your demands and give him a survey where he had to tell me all his requirements ordered by priority. once that was done I spent two weeks investigating possible options and I indicated him some elements that could not be possible to include with the budget that he indicated me. Once we agreed I started doing a deep research on the subject.

Comparing the parameters required for the client, with the laws regarding standards, safety and of course the budget of the disposal, I started researching the materials used in the market, and materials that are currently being developed to see if I could find a competitive advantage. For example for the manufacture of the cylinder and the mechanism of the valves I came to the conclusion that the best material could be steel because of the mechanical properties, ease to manufacture and its price. Then I studied different steels. To find the most appropriate because of the price, as availability or weight.

I had to develop a research for each component and also I had to study physics and engineering principles in order to be sure the use of this device not compromise the safety of my costumer, but also to make sure that the equipment could be used for 15 years as it had been indicated by my client.

For this I studied different engineering books and some websites to deepen the knowledge of these, and then I went to the action carrying out calculations of the forces necessary for the possible lifting of the car, the required diameter of the piston, the pressure which would be subjected to the cylinder and the resistance of the assembly to support the weight of the car.

After carrying out calculations satisfactorily, I had to study the minimum security factors required in order to be safe. As the responsible of product I increase even more these factor so that the material allowed me.

Once all of the calculations were correct, I proceed to the study of different prototypes, I took into account these parameters that had been given by my client.

In them I focused on the aesthetics, size, weight, radius of use thanks to the extension of the cable, ease of use, robustness of the product, safety and especially final cost.

After designing 25 prototypes, I chose the top four, as these were the most similar to the ideal customer product.

For the final choice of the prototype I used different techniques and theories, including of course the comparison of the prototypes using matrix table, which is an excellent tool for comparison of prototypes, taking into account different parameters.

Then stated with the evaluation of the matrix comparing these four prototypes analysing all the parameters to be met.

The most important information I obtained from the survey, because those were the most important features to satisfy my client. The problem is that sometimes the client wants things that can not be done by legal issues, security, standards or even because of the budget.

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So ultimately the most important, useful information is the matrix table, because in that table we compare customer needs (parameters) with the possible characteristics (PDS) that each prototype have, so as soon as I finished the analysis comparing all the parameters and prototypes I arrived at the most satisfactory solution for the customer in order to satisfy cost, standards, laws and requirements of the customer.

Once I finished the comparison I have come to conclude that the best prototype was the number 4, that's why I delivered to the customer the full design of the final prototype with all its technical features.

The only problem was aesthetics, but after analysing customer priorities and all aspects of his product, he understood that it could not be more elegant or aesthetic unless she gave me a chance to increase the budget, and the client was adamant in budget, he understood the limitations that I had to satisfy in that regard, so he he was pleased.

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Engineering design specifications