STRUCTURE OF UMBRELLA

STRUCTURE  OF UMBRELLA

 

Spin your umbrellas under the rain girls; this season is a reason to look cute with small canopies and raincoats and boys may be still shy enough to carry one; but sometimes rain is no excuse! Cool and calm colored canopies with designs that wold follow your aesthetic sense may be much interesting for you from engineering point of view.

Umbrella is a highly mechanical device as defined it is a handhold portable shade to be used in rain. Most of us carry umbrella as a tool to protect from sunlight too but actually parasols are used o this purpose. Mentioning here that both are similar in structure but the only difference is in the stuff used to make them.

History of collapsible parasols is as old as 21 A.D. invented by a Chinese named Wang Mang. Not only in China but Ancient history of Egypt, Greece and Indian subcontinent tells that this device was a part of use by people living there and predominately considered as an article for females.

Various forms are available with modifications in the general design of a collapsible umbrella that consists of a lean shaft with handle for holding at one end of it and shade on another. with wiry rods or spokes type structure for supporting  shade that is usually of fiber like material. I am going to explain the about the 'Compact Umbrella' that is small enough to fit in to your  bag; that is why also known as purse umbrella .

 Compact Umbrellas are designed in a way that these may shrink in to a smaller size for easy in portability along with lesser weight. For the purpose the two components are varied in design; these are:

1. Shaft
2. Fold-able arms

A hollow shaft with less weight is required that can vary in length i.e. gets long to the required length and then back to smaller vertical dimension when needed. Shaft consists of 4 or 5 smaller shafts having diameter slightly greater than the previous one connected to it; moving inn a way that one with smallest diameter stands near the handle. Inside the whole of the shaft is provided with a spring for extension and locking. This shaft is known as telescoping shaft. The locking mechanism for the four or five shafts connected in series is a stopping and clutch mechanism. Usually small stopping rings or shat clips are used for the purpose.

Fold-able or collapsible arms are designed in a way that it serves two purpose:

1. A substitute of longer arms or spokes for supporting canopy.
2. To provide greater radial movement for opening by small vertical movement on the main hollow shaft.

Small linkages are connected in a series manner that movement of one is initial for another i.e. relative motion. These spoke like linkages are connected via pins. The whole skeleton looks certainly like the sketch shown below.

Mechanical Riddles

Mechanical Riddles

Let’s check how good a mechanical engineer you are! Unveil the hidden meanings of this set of riddles by lighting up your brains. Think well and then tell the answers by commenting on this post; don’t hesitate as it’s not going to ruin your GPA! :)

Answers will be posted later .....

SEVEN REASONS TO KEEP A MECHANICAL ENGINEERING DICTIONARY WITH YOU ...

SEVEN REASONS TO KEEP A MECHANICAL ENGINEERING DICTIONARY WITH YOU

A mechanical dictionary is a valuable storehouse of hundreds and thousands  of technical terminologies is a living aid to understand  subject and things around us. It is not only for students but also a useful tool fir mechanics, researchers, builders, electricians and workmen etc in their professional life for comprehending the words being used in trade and occupation. Mechanical engineering dictionary is not only an inventory of mechanical terms from mathematics, chemistry, physics, other fields of engineering and miscellaneous information for wider scope.

Its a counsel to the first year students that after getting admission in a program for engineering (not only mechanical but any field of engineering); go and get a an engineering dictionary relative to your field or simply add it on the top of the list of your curriculum books to be bought.

 

 Why Do You Actually Need It??

1.  Usually forty subjects are offered to students by most of the universities for getting a graduation degree in field of mechanical engineering. It is not easy to get all the knowledge of the whole course in few months; to be true not even the grasp over whole of basic knowledge. Most of the books are graded as medium level books not beginners level so all of them do not necessarily  contain the basic definitions. They really don't know what you know! and what you don't!. So keep it with you while reading your book to take assistance.
2. Its a handy way to clutch acronyms, scientific  abbreviations and symbols.
3. Cross-referencing is a definite way of advancing your knowledge about terms that are related or synonymous information with in the same context.
4. A convenient, quick find format lexicon of your field is a blessing for preparing viva-voice.
5. Johny Irvy beautifully exclaimed that half my life is an act of revision and similar importance holds the revision of basic concepts of all courses of engineering. 
6. Pocket sized dictionary is convenient to carry as extract of fundamental handbook of all subjects and memorizing definitions.
7. Read it before going for an interview or a test to get a better comprehension of terminologies that appears to be similar but different in actual, e.g corrosion and erosion.  

REPLACING HINGED DOORS WITH REVOLVING DOORS TO PRODUCE ELECTRICITY

REPLACING HINGED DOORS WITH REVOLVING DOORS TO PRODUCE ELECTRICITY

Albert Camus says that great works are often born on a street corner or a restaurants revolving door. But now a days technical minds say that a little modification in a revolving door can do a great job. Hinged doors can be replaced by energy efficient revolving doors that not only add glamor to the buildings of cinema houses, restaurants, shopping malls and stadiums etc but is another contribution for the greener world. According to the calculations done by the students of University of Engineering and Technology, Lahore, Pakistan, if 10,000 people pass per day with each each passing period to be 2 seconds then approximately 600 W.h of energy can be produced in a day and 222 kW.hr in a year which is equivalent to the  energy produced from burning of 111 kg of coal. Hence installation of this mechanism can prevent 0.33 tones of CO2 from polluting the environment.

Technical Poster designed by Syeda Zahra from University o Engineering and Technology, Lahore; showing calculations and results of energy efficient revolving door prototype.

TRANSMISSION SYSTEM OF QINGQI

TRANSMISSION SYSTEM OF QINGQI

Qingqi is a common public ride being used in some area of Lahore as an economic way of traveling. On one hand it provides relief for people with low income but on other hand its a serious cause of Environmental Pollution !!! Reason for its being environment health hazard is another talk; but today i am going to share about the transmission system of a Qingqi rickshaw.

Qingqi is a three wheeler ride. A motor bike without rear wheel is attached with a rear body having seats for passengers and two wheels. There are three basic ways to transmit engine power to the rear wheel of a motorcycle:

    1. Chain

    2. Belt

    3. or Shaft

Chain final-drive systems are by far the most common. in transmission system of Qingqi, a sprocket mounted to the output shaft (i.e., the shaft in the transmission) is connected to a sprocket attached to the torsion bar of rickshaw by a metal chain. When the transmission turns the smaller front sprocket attached to the torsion bar of rickshaw by a meal chain. When the transmission turns the smaller front sprocket, power is transmitter along the chain to rickshaw, which then turns the rear wheel. this type of system must be lubricated and adjust, and the chain stretches and the sprocket wear, requiring periodic replacement.

LEARNING WITH PROTOS

 

LEARNING WITH PROTOS

Being an engineer have so many times played with efficiency curves, characteristic curves, stress-strain curves etc in due increasing the retention of my knowledge every time. A few seconds ago I was just thinking why I don’t do something to let children provide an opportunity to shoot out their LEARNING CURVES!!!

In this real battle of BRAINSTORM we can let us our new generation learn technology and physical phenomenon through prototypes developed by little efforts of engineers that can provide opportunity for kids to understand scientific things and even a golden chance for engineering students to learn more by developing prototypes for different phenomenon. 

It would be my pleasure to share one of my prototypes for letting others to understand what I am trying to say. This prototype works on the simple concept of noise cancellation through superposition; so basically it’s a prototype circuit of a simple noise cancellation device.

This device uses the simple phenomena of superposition of waves that when two or more sound waves from different sources are present at the sound waves are180° out of shift, the sum of the waveforms would be zero. They would cancel out each other and ultimately there would be no sound. Basically sound is a compression wave in air so the wave first compresses to an amount greater than normal air pressure; so adding the positive and negative pressure will ultimately give you the normal air pressure.
You can develop prototype of such a simple active noise cancellation device. All you need to do is to follow the circuit as shown bellow.
In this circuit we use a step down transformer to reduce 240V to 12V. Oscillator provides us with the pure-tone (simplest periodic sound) sound which is fed to the first speaker. Oscillator is further connected to Audio-inverter like 741 operational amplifier which inverts the sound and the shift of the sound is decided by using adjuster attached with the inverter. This inverted sound is further amplified and fed to the second speaker. When we switch on the device and rotate adjuster to give a 180° shift then no sound would be heard but you can feel the vibrations by putting your finger on any of the speaker.
To teach anyone anything let that person to think and move one by CREATING CUROSITIES. If engineers unlock their minds and also work out on these miniature things then it can offer a chance for them to think and invent new things and would definitely provide an opportunity to young learners understands and things and intriguing them towards technology.

HERO'S FOUNTAIN

HERO’S FOUNTAIN

Don’t you think that our ancestors were smarter than us that designed the stuffs with no electrical cord or batteries or obvious energy input of any kind? Hero’s fountain that can spout and spray gracefully is an obvious example of it. At first, the fountain looks like a perpetual motion machine. With time, however, and careful observation, a transfer of water can be noticed from a higher reservoir to a lower one, revealing the fountain to be nothing more than an elaborate siphon.

How to build it?

It's quite simple to build a hero's fountain from common household.

Things You Need:

(3) 16.9 FL OZ Water bottles 

(1) 9″ length of tubing

(1) 11″ length of tubing

(1) 15″ length of tubing

Small amount of clay (Play-Doh) 

Scissors

Drill (hand or electric powered)

5/32″ drill bit (slightly smaller than the tubing diameter)

Method 

 Step 1:

Cut (1) of the bottles in half as pictured. Keep the bottom of the bottle, you can use it to fill the fountain when we are all done.

 

Step 2:

You are going to need (2) holes in each cap. Start by drilling the (2) holes in (1) cap, use a piece of scrap wood to support the cap. When you are done with the first cap, use it as a guide to drill (2) holes into the top of the remaining (2) caps. You can place the caps top-to-top when drilling the holes. Now you should have (3) caps, each with (2) holes drilled in about the same location.

Step 3:

Take one of the caps and use it as a guide to drill (2) holes in the bottom of one of the remaining intact bottles. This will end up being bottle {b} as in the diagram below.

 

 Step 4:

Connect the tubing as in the below diagram. All connections should be airtight. If you used the 5/32 drill bit they should be. If not, just add a small amount of clay (Play-Doh) to seal the openings around the tubing. I had to seal the area between bottle {a} & {b}. You can see it in the first picture. The other connections didn’t leak and I did not use any clay.

 

Step 5:

Now all you have to do is fill bottle {b} with water and screw the whole system together. To start your fountain, add water to the upper bottle {a}. Enjoy your homemade Heron’s Fountain.