EOT ASSIGNMENT BICYCLE
- 1. NATIONAL INSTITUTE OF FASHION TECHNOLOGY KOLKATA SUBJECT: ELEMENTS OF TECHNOLOGY FACULTY: Mr. BIBEKANANDA BANARJEE ASSIGNMENT 1 BICYCLE NAME: VAIBHAV RAJ ROLL NO: BFT/21/272
- 2. HOW DO BICYCLES WORK? Bicycles are used by millions of people worldwide, for various reasons. People use bicycle to work out, commute, deliver packages, compete in races, or just ride for fun. Riding a bicycle might seem easy to some, but it’s actually very complex. Both the rider and the bike play an integral role in the process, which is really more of a science than an art. So, how exactly does this two-wheeled object get us from Point A to Point B? Bicycles turn energy created by our bodies into kinetic energy. Kinetic energy is “a property of a moving object or particle and depends not only on its motion but also on its mass”. If work, which transfers energy, is done on an object by applying a net force, the object speeds up and thereby gains kinetic energy. A bicycle can convert up to 90 percent of a person’s energy and movement into kinetic energy. This energy is then used to move the bike. The rider’s balance and momentum help keep the bike stable while traveling along a path. MACHINES USED IN BICYCLES Bicycle is a composite of several simple machines. Simple machines found on a bicycle are: 1. Lever, 2. Pulley, 3. Wheel-and-axle. 4. Bearings 5. Power screws 6. Gear 7. Sprocket 8. Chain 9. Cam 10.Crank arm Each one is used to transfer energy.
- 4. PICTURE SHOWING USES 0F SOME IMPORTANT PARTS
- 5. THE SCIENCE BEHIND THIS ‘SIMPLE’ MACHINE. Science Behind the Bicycle: Examples of where the simple machines can be found on a bicycle: • wheel and axle pedals and crank; back wheel and axle • lever steering; pedals and crank; gear shift; brakes • pulley, chain and gear Examples of energy transfer through these simple machines: • energy on the pedals is transferred to chain • energy on handlebars used to turn the wheel • energy on the brake handle transferred to brake pad • energy of the rear wheel and axle transferred to the road 1. WHEELS How Bicycle Wheels Work: A bicycle wheel and the axle it turns is an example of a simple machine. It’ll accumulate force (speed) depending on how you turn it. Bicycle wheels are typically taller than most car wheels. The taller the wheels, the more they multiply your speed when you turn the axle. The wheels ultimately support your entire weight but in a very interesting way. If bicycle wheels were completely solid, they’d squash down as you sat on the seat and push back up to support you. However, the wheels of most bikes are formed by using a strong hub with a thin rim and several spokes. Bicycles have spoked wheels to make them both strong and lightweight and to lessen drag.
- 6. 2. GEARS How Bicycle Gears Work: Gears linked by the chain make the machine go faster or make it easier to pedal. Gears can make an incredible difference to your speed. Say the gear ratio on a racing bike is 5:1. This means a single spin of the pedals will power you about 35 feet down the street. The force used by pedalling enables the gears of a bike to spin the back wheel. As the back wheel rotates, the tire uses friction to grip the area and move the bike in the desired direction. How much energy are we talking about? You can generate about 10 watts of energy with a hand-cranked electricity generator, though you can’t use one of those for very long without getting tired.
- 7. This tells us that it’s much easier to generate large amounts of power for longer time periods by using your big leg muscles than by using your arms and hands. Bikes make great use of the most powerful muscles in our body. You shift gears by sliding the shifter on the handlebars. On most bikes, this shifts the chain onto a different sized ring. On three-speed bikes, the gears are inside the hub of the wheel so you don't see them. Downshifting means going to a lower gear, and upshifting means going to a higher gear.
- 8. 3. BRAKES How Bicycle Brakes Work: No matter how fast you pedal, you’re always going to need to stop. Brakes on a bicycle work using friction. Although some bikes now have disc brakes, many still use traditional caliper-operated rim brakes with shoes. When you press the brake levers, a pair of rubber shoes clamps onto the metal inner rim of the front and back wheels. As the brake shoes rub firmly against the wheels, they turn your kinetic energy into heat, which has the effect of slowing you down. 4. HANDLE BARS How Bicycle Handlebars Work: The handlebars of a bicycle are actually a type of lever. Longer handlebars provide leverage, which makes it easier to pivot the front wheel of the bike. The further apart you space your arms, the more air resistance you create. The typical outer parts of the handlebars are for steering, and the inner parts are for gliding. The apparently simple two-wheeled machine uses momentum, force, and friction and converts energy to get riders to their destination.
- 9. 5. LEVER How Bicycle Lever Works The lever on a bicycle is the brake lever located on the front handle bars. A cable running from a lever on the handlebars pulls the two levers on the brakes together. This squeezes the brake pads against the outside of the wheel. Some bikes, especially those with suspension systems, use disc brakes. The brake lever uses hydraulic fluid to transmit the force from your hand to the brake shoes.
- 10. 6. PULLEY How Bicycle Pulley Works: A pulley is a wheel on an axle or shaft that is designed to support movement and redirect tension. They are simple, yet powerful devices that can make small forces move large objects. Pulleys are used to make heavy work more manageable. Pulley is located where the bicycle chain and gears are. The chain is wrapped around the pulley which turns and causes the wheel to turn on its axle. The pulley is the chain and gear that help make the bike run, and the wheel and axle are in the front and back tires. B. The bike's pulley transfers energy from the person's body to the chain. The chain then sends the energy to the wheel-and- axle which transfers it to the tire and then onto the road causing movement. How does a pulley make work easy? The pulley, a simple machine, helps to perform work by changing the direction of forces and making easier the moving of large objects. With a type of pulley called a fixed pulley, pulling down on a rope makes an object rise off the ground. There are also movable pulleys and pulley systems.
- 11. 7. WHEEL AND AXLE How Bicycle Wheel and Axle Works: On a bike, the input force is applied in a circular motion, around and around as you pedal. The wheel and axle changes the direction of your force so you move forward in a line. With every pedal, you apply a strong input force over a short distance on the axle to move the wheel a greater distance with less force. How is a wheel and axle useful? Wheel and axle, basic machine component for amplifying force. In its earliest form it was probably used for raising weights or water buckets from wells. Its principle of operation is demonstrated by the large and small gears attached to the same shaft. How does a wheel and axle move? The wheel and axle is a machine consisting of a wheel attached to a smaller axle so that these two parts rotate together in which a force is transferred from one to the other.
- 12. 8. BICYCLE BEARINGS How Bicycle Bearings Works: Bicycle bearings commonly use bearing balls, placed in a cone, compressed with a cup (cup and cone bearing). Cup, with curved walls holds the balls, while the cone presses on top, holding them in place. Cone is screwed onto the axle and presses the balls onto the cup. Bicycle Bearings Bicycles use ball bearings to reduce friction. You can find ball bearings in: • The front and rear hubs for the wheels • The bottom bracket, where an axle connects the two pedal cranks together • The fork tube, where the handlebars are allowed to turn • The pedals • The freewheel, where they do double-duty (In the freewheel, they also help provide the one-directional feature.) What are the benefits of ball bearings? The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls.
- 13. 9. POWER SCREWS What is a power screw? A leadscrew (or lead screw), also known as a power screw or translation screw, is a screw used as a linkage in a machine, to translate turning motion into linear motion. How does a power screw work? A lead screw turns rotary motion into linear motion combining a screw and a nut where the screw thread is in direct contact with the nut thread. In the case of roller screws, the rollers rather than the nut are in direct contact with the screw thread offering greater efficiency.
- 14. 10. SPROCKET How Bicycle Sprocket Works: A sprocket, sprocket-wheel or chain wheel is a profiled wheel with teeth, or cogs, that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passing over it. It is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have teeth and pulleys are smooth except for timing pulleys used with toothed belts. The chain connects the two sprockets. When you turn the pedals, the front sprocket turns. The chain transfers that rotation to the rear sprocket, which turns the rear wheel, and the bicycle moves forward. The faster you turn the pedals, the faster the rear wheel goes, and the faster the bike goes. What does a sprocket do on a bike? Sprockets are used in bicycles, motorcycles, cars, tracked vehicles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or to impart linear motion to a track, tape etc.
- 15. 11. BICYLE CHAIN In a bicycle, the pair of gears is not driven directly but linked by a chain. At one end, the chain is permanently looped around the main gear wheel (between the pedals). At its other end, it shifts between a series of bigger or smaller toothed wheels when you change gear. How does a bike chain work? Bicycle chains are made of multiple pairs of steel outer plates and inner plates held together by rivets. A roller separates each pair of inner plates. The rivet (pin) is pressed tightly through both outer plates. The rivet then pivots freely on the inner plates and roller. 12. CRANK ARM How Bicycle Crank Arm Works: What is a crank arm on a bike? Crank (spider): is the actual section that the chain rings bolt onto. Crank Arms: These are the levers to that your pedals attach to. Chain: The chain is what turns the back wheel when you pedal. Bottom Bracket: This is the housing that holds the bearings in place and the axle that the crank arms attach to.
- 16. The crank set or chain set is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called chain rings or chain wheels attached to the cranks, arms, or crankarms to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain. What is a crank used for? A crank is an arm attached at a right angle to a rotating shaft by which circular motion is imparted to or received from the shaft. When combined with a connecting rod, it can be used to convert circular motion into reciprocating motion, or vice versa.