Design and Fabrication of Shaft Driven Bicycle

DESIGN AND FABRICATION OF SHAFT DRIVEN BICYCLE A PROJECT REPORT Submitted by

CHOKKALINGAM.V (710111114019) KARTHIKEYAN.R (710111114037) MANOJ PRAVEEN.P (710111114045) MOHAN.R (710111114047) In partial fulfillment for the award of the degree of

BACHELOR OF ENGINEERING In

MECHANICAL ENGINEERING ADITHYA INSTITUTE OF TECHNOLOGY, COIMBATORE.

ANNA UNIVERSITY : CHENNAI-600 025 APRIL 2014

ANNA UNIVERSITY CHENNAI-600 025

BONAFIDE CERTIFICATE

Certified that this project report “DESIGN AND FABRICATION OF SHAFT DRIVEN BICYCLE” is the bonafide work of CHOKKALINGAM.V (710111114019), KARTHIKEYAN.R (710111114037), MANOJ PRAVEEN.P (710111114045), MOHAN.R (710111114047) who carried out the project work under my supervision.

SIGNATURE Dr. K.SENTHIL KUMAR, HEAD OF THE DEPARTMENT, Department of Mechanical Engineering, Adithya Institute of Technology, Sathy Main Road, Kurumbapalayam, Coimbatore - 641 107.

SIGNATURE Mr. A.KARTHIKEYAN, ASSISTANT PROFESSOR, SUPERVISOR, Department of Mechanical Engineering, Adithya Institute of Technology, Sathy Main Road, Kurumbapalayam, Coimbatore - 641 107.

Submitted for the Viva Voce held on -------------------

INTERNAL EXAMINER

EXTERNAL EXAMINER

ACKNOWLEDGEMENT

We take this opportunity to express our sincere and deep gratitude to many, who are completely and partially responsible for the knowledge and experience that we have gained during our project and throughout the course. We feel immense gratitude to our beloved Chairman Er.C.SUGUMARAN for his hearty and warm extended support towards us. We shall be ever grateful to our management who helped us for building our career and providing us with good infrastructure facilities. We would like to thank our principal Dr.N.KATHIRAVAN for his support and encouragement during this project. For the successful completion of our project. Our sincere and significant thanks to the head of the mechanical department Dr.K.SENTHILKUMAR who has given us a very conceivable kind of motivation, encouragement and facilities. We wish to place the record of our profound feelings of gratitude to our beloved staff and guide Mr. A.KARTHIKEYAN without his able guidance this project would not see the light of the day. We wish to express our deep gratitude to all mechanical department staff members for the help and valuable suggestion for the completion of the project work. Last but not least we would like to thank our parents for their blessing and support. Without them things in our life would not be what they are.

TABLE OF CONTENTS CHAPTER NO.

TITLE

ABSTRACT

1.

2.

PAGE NO

i

LIST OF TABLES

ii

LIST OF FIGURES

iii

LIST OF GRAPHS

iv

INTRODUCTION

1

1.1 Objective

3

LITERATURE REVIEW

4

2.1 Gears

4

2.2 Flywheel

17

2.3 Bicycle bases

17

2.3.1 Introduction

17

2.3.2 Stationary bicycle

17

2.3.3 Exercise bicycle

18

3.

4.

2.4 Energy output uses for pedal power

18

2.5 Fan belts

20

2.6 Drive choices

20

ALERNATIVE DESIGN SOLUTIONS

21

3.1 Introduction

21

3.2 Brainstorming

25

3.3 Alternative solutions

25

DECISION PHASE 4.1 Introduction

34

4.2 Criteria definition

34

4.3 Solution

35

4.4 Decision process

35

5.

COST ESTIMATION

37

6.

PHOTOGRAPHY

38

7.

CONCLUSION

39

RERERENCES

40

ABSTRACT In this project we design a new innovation of power transmission from pedal to wheel by means of bevel gear in bicycle. The model consists of a bevel gears, rotating shaft arrangement, and bearings. A shaft-driven bicycle is a chainless bicycle that uses a driveshaft instead of a chain to transmit power from the pedals to the wheel. Our model consists of a bevel gear arrangement in it. The whole bicycle is driven by the shaft. A bevel gear arrangement is provided at the rear end of the bike and also with the pedal arrangement.

When the pedal is rotated the shaft also rotates according to the speed of the pedal. The bevel gear is arranged such that the power can be transmitted from the pedal to the rear wheel easily. The bevel gear is used for 90degree power transmission. The bearing blocks are used as the support for the rotating shaft. The front bevel gear arrangement has free wheel arrangement hence when the pedal is stopped the wheel rotates with help of the free wheel.

LIST OF TABLES TABLE NO

5.1

TITLE

PAGE NO

Cost analysis

37

LIST OF FIGURES FIGURE NO

TITLE

6.1

Completed prototype

PAGE NO

38

LIST OF GRAPHS GRAPH NO

TITLE

PAGE NO

2.1

Variation

19

1. INTRODUCTION Aim of our Project is to make new kind of transmission system for bicycle for getting high reliability system, and more safe system. A drive shaft, driveshaft, driving shaft, propeller shaft, or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement between them. Drive shafts are carriers of torque: they are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, whilst avoiding too much additional weight as that would in turn increase their inertia. Drive shafts frequently incorporate one or more universal joints or jaw couplings, and sometimes a splined joint or prismatic joint to allow for variations in the alignment and distance between the driving and driven components. The drive shaft has served as an alternative to a chain-drive in bicycles for the past century, although never becoming very popular. A shaftdriven bicycle is described as an "Acatane", from one of their early makers. When used on a bicycle, a drive shaft has several advantages and disadvantages: With a chain drive transmission, a chainring attached to a crank drives the chain, which in turn rotates the rear wheel via the rear sprocket(s) (cassette or freewheel). There are four gearing options: two-speed hub gear integrated with chain ring, up to 3 chain rings, up to 11 sprockets, hub gear built in to rear wheel (3-speed to 14-speed). The most common options are either a rear hub or multiple chain rings combined with multiple sprockets (other combinations of options are possible but less common).With a shaft drive transmission, a gear set at the bottom bracket turns the shaft, which then turns the rear wheel via a gear set connected to the wheel's hub. There is some small loss of efficiency due to the two gear sets needed. The only gearing option with a shaft drive is to use a hub gear.

Advantages 

Drive system is less likely to become jammed, a common problem with chain-driven bicycles 

The rider cannot become dirtied from chain grease or injured by the chain from "Chain bite", which occurs when clothing or even a body part catches between the chain and a sprocket

 

Lower maintenance than a chain system when the drive shaft is enclosed in a tube More consistent performance. Dynamic Bicycles claims that a drive shaft bicycle can deliver 94% efficiency, whereas a chain-driven bike can deliver anywhere from 7597% efficiency based on condition



Greater clearance: with the absence of a derailleur or other low-hanging machinery, the bicycle has nearly twice the ground clearance

Disadvantages 

A drive shaft system weighs more than a chain system, usually 1-2 pounds heavier



Many of the advantages claimed by drive shaft's proponents can be achieved on a chain-driven bicycle, such as covering the chain and gears with a metal or plastic cover 

Use of lightweight derailleur gears with a high number of ratios is impossible, although hub gears can be used



Wheel removal can be complicated in some designs (as it is for some chain-driven bicycles with hub gears).

The purpose of the design process is to define an objective statement for the design process. The objective presents the measurable end point that shows whether the solution is achieved.

1.1 Objective The objective of this design project is to create a mechanical bicycle that educates visitors about sustainability and energy conservation by enabling them to generate renewable energy. It

will accomplish this by creating a physical model that converts kinetic energy from a bicycle into mechanical energy.

2. LITERATURE REVIEW 2.1 Gears A gear or cogwheel is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque, in most cases with teeth on the one gear being of identical shape, and often also with that shape on the other gear. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, torque, and direction of a power source. The most common situation is for a gear to mesh with another gear; however, a gear can also mesh with a non-rotating toothed part, called a rack, thereby producing translation instead of rotation. The gears in a transmission are analogous to the wheels in a crossed belt pulley system. An advantage of gears is that the teeth of a gear prevent slippage. When two gears mesh, and one gear is bigger than the other (even though the size of the teeth must match), a mechanical advantage is produced, with the rotational speeds and the torques of the two gears differing in an inverse relationship. In transmissions which offer multiple gear ratios, such as bicycles, motorcycles, and cars, the term gear, as in first gear, refers to a gear ratio rather than an actual physical gear. The term is used to describe similar devices even when the gear ratio is continuous rather than discrete, or when the device does not actually contain any gears, as in a continuously variable transmission.

Types External vs. internal gears

Internal gear An external gear is one with the teeth formed on the outer surface of a cylinder or cone. Conversely, an internal gear is one with the teeth formed on the inner surface of a cylinder or cone. For bevel gears, an internal gear is one with the pitch angle exceeding 90 degrees. Internal gears do not cause output shaft direction reversal. Spur

Spur gears or straight-cut gears are the simplest type of gear. They consist of a cylinder or disk with the teeth projecting radially, and although they are not straight-sided in form (they are usually of special form to achieve constant drive ratio, mainly involute), the edge of each tooth is straight and aligned parallel to the axis of rotation. These gears can be meshed together correctly only if they are fitted to parallel shafts. Helical

Helical or "dry fixed" gears offer a refinement over spur gears. The leading edges of the teeth are not parallel to the axis of rotation, but are set at an angle. Since the gear is curved, this angling causes the tooth shape to be a segment of a helix. Helical gears can be meshed in parallel or crossed orientations. The former refers to when the shafts are parallel to each other; this is the most common orientation. In the latter, the shafts are non-parallel, and in this configuration the gears are sometimes known as "skew gears". The angled teeth engage more gradually than do spur gear teeth, causing them to run more smoothly and quietly. With parallel helical gears, each pair of teeth first make contact at a single point at one side of the gear wheel; a moving curve of contact then grows gradually across the tooth face to a maximum then recedes until the teeth break contact at a single point on the opposite side. In spur gears, teeth suddenly meet at a line contact across their entire width causing stress and noise. Spur gears make a characteristic whine at high speeds. Whereas spur gears are used for low speed applications and those situations where noise control is not a problem, the use of helical gears is indicated when the application involves high speeds, large power transmission, or where noise abatement is important. The speed is considered to be high when the pitch line velocity exceeds 25 m/s. A disadvantage of helical gears is a resultant thrust along the axis of the gear, which needs to be accommodated by appropriate thrust bearings, and a greater degree of sliding friction between the meshing teeth, often addressed with additives in the lubricant.

Skew gears For a 'crossed' or 'skew' configuration, the gears must have the same pressure angle and normal pitch; however, the helix angle and handedness can be different. The relationship between the two shafts is actually defined by the helix angle(s) of the two shafts and the handedness. Quite commonly, helical gears are used with the helix angle of one having the negative of the helix angle of the other; such a pair might also be referred to as having a right-handed helix and a left-handed helix of equal angles. The two equal but opposite angles add to zero: the angle between shafts is zero – that is, the shafts are parallel. Where the sum or the difference (as described in the equations above) is not zero the shafts are crossed. For shafts crossed at right angles, the helix angles are of the same hand because they must add to 90 degrees.



3D Animation of helical gears (parallel axis)



3D Animation of helical gears (crossed axis)

Double helical

Double helical gears, or herringbone gears, overcome the problem of axial thrust presented by "single" helical gears, by having two sets of teeth that are set in a V shape. A double helical gear can be thought of as two mirrored helical gears joined together. This arrangement cancels out the net axial thrust, since each half of the gear thrusts in the opposite direction resulting in a net axial force of zero. This arrangement can remove the need for thrust bearings. However, double helical gears are more difficult to manufacture due to their more complicated shape. For both possible rotational directions, there exist two possible arrangements for the oppositely-oriented helical gears or gear faces. One arrangement is stable, and the other is unstable. In a stable orientation, the helical gear faces are oriented so that each axial force is directed toward the center of the gear. In an unstable orientation, both axial forces are directed away from the center of the gear. In both arrangements, the total (or net) axial force on each gear is zero when the gears are aligned correctly. If the gears become misaligned in the axial direction, the unstable arrangement will generate a net force that may lead to disassembly of the gear train, while the stable arrangement generates a net corrective force. If the direction of rotation is reversed, the direction of the axial thrusts is also reversed, so a stable configuration becomes unstable, and vice versa. Stable double helical gears can be directly interchanged with spur gears without any need for different bearings.

Bevel

A bevel gear is shaped like a right circular cone with most of its tip cut off. When two bevel gears mesh, their imaginary vertices must occupy the same point. Their shaft axes also intersect at this point, forming an arbitrary non-straight angle between the shafts. The angle between the shafts can be anything except zero or 180 degrees. Bevel gears with equal numbers of teeth and shaft axes at 90 degrees are called miter gears.

Spiral bevels

Spiral bevel gears can be manufactured as Gleason types (circular arc with non-constant tooth depth), Oerlikon and Curvex types (circular arc with constant tooth depth), Klingelnberg Cyclo-Palloid (Epicycloide with constant tooth depth) or Klingelnberg Palloid. Spiral bevel gears have the same advantages and disadvantages relative to their straight-cut cousins as helical gears do to spur gears. Straight bevel gears are generally used only at speeds below 5 m/s (1000 ft/min), or, for small gears, 1000 r.p.m. Note: The cylindrical gear tooth profile corresponds to an involute, but the bevel gear tooth profile to an octoid. All traditional bevel gear generators (like Gleason, Klingelnberg, Heidenreich & Harbeck, WMW Modul) manufactures bevel gears with an octoidal tooth profile. IMPORTANT: For 5-axis milled bevel gear sets it is important to choose the same calculation / layout like the conventional manufacturing method. Simplified calculated bevel gears on the basis of an equivalent cylindrical gear in normal section with an involute tooth form show a deviant tooth form with reduced tooth strength by 10-28% without offset and 45% with offset [Diss. Hünecke, TU Dresden]. Furthermore those "involute bevel gear sets" causes more noise.

Hypoid

Hypoid gears resemble spiral bevel gears except the shaft axes do not intersect. The pitch surfaces appear conical but, to compensate for the offset shaft, are in fact hyperboloids of revolution. Hypoid gears are almost always designed to operate with shafts at 90 degrees. Depending on which side the shaft is offset to, relative to the angling of the teeth, contact between hypoid gear teeth may be even smoother and more gradual than with spiral bevel gear teeth, but also have a sliding action along the meshing teeth as it rotates and therefore usually require some of the most viscous types of gear oil to avoid it being extruded from the mating tooth faces, the oil is normally designated HP (for hypoid) followed by a number denoting the viscosity. Also, the pinion can be designed with fewer teeth than a spiral bevel pinion, with the result that gear ratios of 60:1 and higher are feasible using a single set of hypoid gears. This style of gear is most commonly found driving mechanical differentials; which are normally straight cut bevel gears; in motor vehicle axles.

Crown

Crown gears or contrate gears are a particular form of bevel gear whose teeth project at right angles to the plane of the wheel; in their orientation the teeth resemble the points on a crown. A crown gear can only mesh accurately with another bevel gear, although crown gears

are sometimes seen meshing with spur gears. A crown gear is also sometimes meshed with an escapement such as found in mechanical clocks.

Worm

Worm gears resemble screws. A worm gear is usually meshed with a spur gear or a helical gear, which is called the gear, wheel, or worm wheel. Worm-and-gear sets are a simple and compact way to achieve a high torque, low speed gear ratio. For example, helical gears are normally limited to gear ratios of less than 10:1 while worm-and-gear sets vary from 10:1 to 500:1. A disadvantage is the potential for considerable sliding action, leading to low efficiency. Worm gears can be considered a species of helical gear, but its helix angle is usually somewhat large (close to 90 degrees) and its body is usually fairly long in the axial direction; and it is these attributes which give it screw like qualities. The distinction between a worm and a helical gear is made when at least one tooth persists for a full rotation around the helix. If this occurs, it is a 'worm'; if not, it is a 'helical gear'. A worm may have as few as one tooth. If that tooth persists for several turns around the helix, the worm will appear, superficially, to have

more than one tooth, but what one in fact sees is the same tooth reappearing at intervals along the length of the worm. The usual screw nomenclature applies: a one-toothed worm is called single thread or single start; a worm with more than one tooth is called multiple thread or multiple start. The helix angle of a worm is not usually specified. Instead, the lead angle, which is equal to 90 degrees minus the helix angle, is given. In a worm-and-gear set, the worm can always drive the gear. However, if the gear attempts to drive the worm, it may or may not succeed. Particularly if the lead angle is small, the gear's teeth may simply lock against the worm's teeth, because the force component circumferential to the worm is not sufficient to overcome friction. Worm-and-gear sets that do lock are called self locking, which can be used to advantage, as for instance when it is desired to set the position of a mechanism by turning the worm and then have the mechanism hold that position. An example is the machine head found on some types of stringed instruments. If the gear in a worm-and-gear set is an ordinary helical gear only a single point of contact will be achieved. If medium to high power transmission is desired, the tooth shape of the gear is modified to achieve more intimate contact by making both gears partially envelop each other. This is done by making both concave and joining them at a saddle point; this is called a cone-drive. or "Double enveloping" Worm gears can be right or left-handed, following the long-established practice for screw threads. Non-circular

Non-circular gears are designed for special purposes. While a regular gear is optimized to transmit torque to another engaged member with minimum noise and wear and maximum efficiency, a non-circular gear's main objective might be ratio variations, axle displacement

oscillations and more. Common applications include textile machines, potentiometers and continuously variable transmissions. Rack and pinion

A rack is a toothed bar or rod that can be thought of as a sector gear with an infinitely large radius of curvature. Torque can be converted to linear force by meshing a rack with a pinion: the pinion turns; the rack moves in a straight line. Such a mechanism is used in automobiles to convert the rotation of the steering wheel into the left-to-right motion of the tie rod(s). Racks also feature in the theory of gear geometry, where, for instance, the tooth shape of an interchangeable set of gears may be specified for the rack (infinite radius), and the tooth shapes for gears of particular actual radii are then derived from that. The rack and pinion gear type is employed in a rack railway.

Epicyclic

In epicyclic gearing one or more of the gear axes moves. Examples are sun and planet gearing (see below) and mechanical differentials. Sun and planet

Sun and planet gearing was a method of converting reciprocating motion into rotary motion in steam engines. It was famously used by James Watt on his early steam engines in order to get around the patent on the crank but also had the advantage of increasing the flywheel speed so that a lighter flywheel could be used. In the illustration, the sun is yellow, the planet red, the reciprocating arm is blue, the flywheel is green and the driveshaft is grey.

Harmonic drive

A harmonic drive is a specialized gearing mechanism often used in industrial motion control, robotics and aerospace for its advantages over traditional gearing systems, including lack of backlash, compactness and high gear ratios. Cage gear

A cage gear, also called a lantern gear or lantern pinion has cylindrical rods for teeth, parallel to the axle and arranged in a circle around it, much as the bars on a round bird cage or lantern. The assembly is held together by disks at either end into which the tooth rods and axle are set. Lantern gears are more efficient than solid pinions,[citation needed] and dirt can fall through the rods rather than becoming trapped and increasing wear. They can be constructed with very simple tools as the teeth are not formed by cutting or milling, but rather by drilling holes and inserting rods. Sometimes used in clocks, the lantern pinion should always be driven by a gearwheel, not used as the driver. The lantern pinion was not initially favored by conservative clock makers. It became popular in turret clocks where dirty working conditions were most commonplace. Domestic American clock movements often used them. Magnetic gear All cogs of each gear component of magnetic gears act as a constant magnet with periodic alternation of opposite magnetic poles on mating surfaces. Gear components are mounted with a backlash capability similar to other mechanical gearings. Although they cannot exert as much force as a traditional gear, such gears work without touching and so are immune to wear, have very low noise and can slip without damage making them very reliable. They can be used in configurations that are not possible for gears that must be physically touching and can operate with a non-metallic barrier completely separating the driving force from the load, in this

way they can transmit force into a hermetically sealed enclosure without the use of a radial shaft seal which may leak. Gear materials

Numerous nonferrous alloys, cast irons, powder-metallurgy and plastics are used in the manufacture of gears. However, steels are most commonly used because of their high strengthto-weight ratio and low cost. Plastic is commonly used where cost or weight is a concern. A properly designed plastic gear can replace steel in many cases because it has many desirable properties, including dirt tolerance, low speed meshing, the ability to "skip" quite well and the ability to be made with materials not needing additional lubrication. Manufacturers have employed plastic gears to reduce costs in consumer items including copy machines, optical storage devices, cheap dynamos, consumer audio equipment, servo motors, and printers.

The module system Countries which have adopted the metric system generally use the module system. As a result, the term module is usually understood to mean the pitch diameter in millimeters divided by the number of teeth. When the module is based upon inch measurements, it is known as the English module to avoid confusion with the metric module. Module is a direct dimension, whereas diametral pitch is an inverse dimension (like "threads per inch"). Thus, if the pitch diameter of a gear is 40 mm and the number of teeth 20, the module is 2, which means that there are 2 mm of pitch diameter for each tooth.[22]

Manufacture

Gears are most commonly produced via hobbing, but they are also shaped, broached, and cast. Plastic gears can also be injection molded; for prototypes, 3D printing in a suitable material can be used. For metal gears the teeth are usually heat treated to make them hard and more wear resistant while leaving the core soft and tough. For large gears that are prone to warp, a quench press is used. Inspection Gear geometry can be inspected and verified using various methods such as industrial CT scanning, coordinate-measuring machines, white light scanner or laser scanning. Particularly useful for plastic gears, industrial CT scanning can inspect internal geometry and imperfections such as porosity.

Gear model in modern physics Modern physics adopted the gear model in different ways. In the nineteenth century, James Clerk Maxwell developed a model of electromagnetism in which magnetic field lines were rotating tubes of incompressible fluid. Maxwell used a gear wheel and called it an "idle wheel" to explain the electrical current as a rotation of particles in opposite directions to that of the rotating field lines. More recently, quantum physics uses "quantum gears" in their model. A group of gears can serve as a model for several different systems, such as an artificially constructed nanomechanical device or a group of ring molecules.

2.2 Flywheel Flywheels are designed to store and release mechanical energy. A Flywheel is discshaped, and true to its weight on all sides and locations of the disk. The bigger and heavier the flywheel, the more power can be produced and at a steadier rate of production, but there is a trade off with the amount of energy needed to get larger flywheels in motions. As a flywheel spins faster, it accumulates more energy. As it slows down, it releases that energy stored and increases the rotational momentum put out by its power source. Flywheels are made out of steel, but they can be created out of any material that can be manipulated into a wheel. Concrete, rebar, and plywood are all capable materials. (Dean, Tamar. 2008.)

2.3 Bicycle Bases 2.3.1 Introduction This section covers the various bases and design structures that will hold the bike upright and secure its position while the operator is in use. The following topics cover both advantages and disadvantages of the selected bicycle structures.

2.3.2 Stationary Bicycle Stationary bikes are cheap, easily and readily available and are converted from regular road or commuter bike. A stationary bicycle requires the use of a PPU or Pedal Power Unit. The Pedal Power Unit allows for the bike to remain stationary while still being able to produce momentum and energy from pedaling.

2.3.3 Exercise Bicycle Exercise bikes are constructed stationary and come equipped with a built in flywheel, like the Schwinn Model Exercise Bike shown below in Figure 2-1. The flywheel has to be removed and its weight adjusted to match the appropriate amount of energy output the mechanical bike must supply.

Schwinn Recumbent Exercise Bike

2.4 Energy output and uses for pedal power The circular pedaling motion at speeds of 60-80 revolutions per minute and transmitting power by sprocket-and-chain mechanisms and ball bearings can convert about 95% of muscle energy of bicycle (Wilson, David Gordon). By pedaling, a person can produce four times more energy than by hand movements. Torque is produced from the operator’s feet and is transferred to a sprocket and chain that ranges from one third of the maximum torque produced. The use of stationary bicycle, flywheel, elliptical sprocket and gear ratios can minimize torque and increase the amount of generated energy. According to the tests done at Oxford University, an average bike rider travels at speeds of 12 mph. This speed can produce 1/10 hp (75 watts/sec). Speeds of 18 mph can produce ¼ hp (200 watts/sec). At a rate of ¼ hp, the human body can pedal continuously for 10 min, but at a rate of 1/8 hp, continuous pedaling can last up to one hour (Wilson, David Gordon). The Figure presents the change in optimum rate of pedaling with different power inputs. Most blenders use between 600-1500 watts of energy, which clearly shows that besides burning calories, pedal power can significantly contribute to reducing energy bills. Pedal power can provide energy to the following operations: Meat grinder, wood carver, stone polisher and buffer, jewelers lathe, pottery wheel, juicer, potato peeler, meat slicer, cherry pitter, a butter churn and many more items (Wilson, David Gordon).

Graph 2.1 Variation of Optimum Pedaling Rate Varies with Power input

2.5 Fan belts Fan belts are durable and lightweight. The fan belt must be large enough to cover the circumference of the flywheel, generator wheel, and the distance between each wheel. The two types of fan belts commonly used in pedal power are tooth belts and V-Belts as shown below in Figure. Tooth belts have a higher efficiency than smooth V-Belts. The fitted gripping on the Tooth belts allows for a stronger hold and maximizes the friction between the belt and flywheel. (Tuan, Roger. 2010.)

2.6 Drive Choices 2.6.1 Introduction The kitchen appliance powered by the bicycle requires a drive mechanism to successfully convert pedal power into mechanical energy .The chain, belt, and friction drives are all options for this process of energy transfer.

2.6.2 Belt Drive The belt drive transfers power with two rotating discs connected by a belt. The belt drive is among the easiest selected drives to assemble as well as the cheapest. The efficiency of the drive’s energy transfer is in direct relationship with the tension that is applied to the belt. If too little tension is applied the efficiency will greatly drop. If too much tension is applied the belt will wear down much faster and will need to be replaced regularly decreasing its durability. (Dean, Tamar. 2008.)

Belt Drive connected to two wheels 2-1

2.6.3 Chain Drive The chain drive is similar to the belt drive. Two toothed wheels connected by a chain mechanically power the chain drive. The drive offers the best efficiency among the three belts. The chain drive requires a specific type of assembly, if not the durability of the chain will be

reduced significantly. This drive allows for gears and gear ratios, from more torque to higher speed.

Chain Drive attached to two wheels

2.6.4 Friction Drive The friction drive utilizes the rotational energy from a flywheel using friction between two wheels to spin a shaft. The friction drive’s efficiency is of the lowest between the selected drives with an average of ninety percent. Although grinding against a flywheel, the friction drive still requires the use of a belt or chain drive in order to rotate the flywheel. Friction drives are readily available for purchase and can also be custom made out of recyclable materials scrapped off old bicycles. The main components of a friction drive are: The spinning attachment positioned on the bottom of the drive. This part makes contact with the flywheel and spins with accordance to it. The second part of the friction drive is the Rotating shaft located inside the hollow cylinder. Finally, the end extension (Figure 2-6) that attaches to a mechanical appliance and powers the device through the momentum received from its energy supplier. ( McCullagh, James C.)

The Example of the Friction Drive used in the Mechanical Munchy-Maker

3. ALTERNATIVE DESIGN SOLUTIONS 3.1 Introduction The purpose of the alternative design solutions is to brainstorm and develop a variety of design solutions for the mechanical bike. The brainstorming section includes a range of ideas on the design for the bike, construction of the bike, different mechanisms that could be powered, and materials needed for construction. The alternative solutions are drawn up from the research present in previous sections. These are represented by nine alternative solutions. Drawing for shaft driven (bevel gear) bicycle

3.2 Brainstorming In order to find a wide range of possible solutions to design problem, the Samoa Solutions team held two brainstorming sessions. Three approaches were implemented: unstructured approach, structured approach and tree approach. Unstructured approach is used to generate as much ideas as possible regarding specific categories. Structured method is used to create a better overview of ideas. The tree approach is used to display a relationship between categories and ideas. Brainstorming notes are placed at Appendix A.

3.3 Alternative Solutions In order to come up with a viable solution to the problem many ideas or solutions must be thought up. There were nine possible variations of our solution resulted from brainstorming: 

Upright bike



Exercise bike



Heavy flywheel



Light flywheel



Gear ratio



Friction drive



Chain drive



Tooth belts



V belts

3.3.1 Upright Bike The upright bike design has a stationary bike (Figure) attached to a pedal power unit to the front and back of the bicycle to keep the wheels from making contact with the ground while the bike is in use. A frame is constructed on the front of the bike to hold a piece of wood above the front tire. A hole is drilled in the board and a rod that is attached to the blender is extended down to the tire. A piece is fitted at the very end of the rod that touches the tire. When the operator beings to pedals the bike the tire begins to spin which transfers the energy to the piece touching the tire which causes the rod to spin. This makes the blades of the blender rotate. This design still allows for the bike to be able to be removed from the stand and is still readable.

Road bicycle blender The Figure shows how bicycle mechanism to power a blender is adapted to a road bicycle. Two trainers are attached to wheels. Chain is attached to a front flywheel, the movement of which transfers power to a drive, which transfers it to a blender.

3.3.2 Exercise Bike The exercise bike works in a similar to the design above, upright bike (Figure). The difference is this design uses an exercise bike. The exercise bike wheel is also heavier than a road bike tire so it can build up more momentum and provide power to items that need a greater input of energy. The heavier flywheel does have an impact on how much energy is needed to start the bike so the size of the flywheel has to be limited, so that it is still easy to get started.

Exercise bike

3.3.3 Flywheel The flywheel is designed to provide a more steady flow of momentum to the selected drive powering the mechanical kitchen appliance. The size and weight of the flywheel will determine the amount of energy that can be produced from peddling the bike. The mechanical advantages to using a flywheel is that its energy output is consistent and, depending on the size of the flywheel, it is able to store and release great amounts of energy even after the peddling has ceased.

3.3.3.1 Heavy Flywheel A heavy flywheel (Figure) will take much more effort to get started but will be able to provide the steadiest flow of energy once the heavy weighted disk is in motion. The disadvantage in using a heavy flywheel to power a mechanical device such as a blender is that the energy being supplied would overwhelm the device. The individual peddling the bicycle would also have a hard time getting the wheel’s momentum engaged and would require more energy input than is required.

Heavy Flywheel The Figure shows a placement of a flywheel into a bicycle power mechanism. 3.3.3.2 Light Flywheel A light flywheel (Figure 3-3) will be easy to engage through peddling power. The amount of momentum is not as great as a heavier flywheel but will be sufficient enough to power a small device such as a blender. A flywheel weighing about 25-35 pounds is light enough for an individual to mechanically power, and is able to provide a stream of 90+ RPM (Revolutions per Minute).

Light Flywheel The Figure shows a light flywheel that would be applied to the bicycle.

3.3.4 Gear Ratio The gear ratio will determine the speed and torque power of the mechanical bicycle (Figure 3-4). Gear Ratios are a ratio between the numbers of teeth found on the gear. Using a smaller gear in front, by the pedals, and a larger gear placed in the back of the bike that is connected to the wheel, will allow for a power ratio, and will increase the amount of cycles needed per full rotation of the wheel, which increases the torque.

Gear ratio

3.3.5 The friction Drive The friction drive is a drive that works by using two wheels to transfer power to the appliance. This drive allows for a very user-friendly experience, in turn, the general life of the drive is shorter because of the pressure the wheels put on each other. From what we found in our literature reviews, this is the quietest drive available. Set up correctly, the drives efficiency is very high, but over a long period of time it will drop as the two wheels become worn down. As shown in Figure 3-5, the drive shaft of the blender extends down and has a rubber wheel on it. That wheel is in contact with the drive wheel on the bike. This set up will allow the user to easily remove the blender for pouring and/or cleaning.

Friction Drive This figure shows the bikes general set up and goes into depth with how the friction drive operates.

3.3.6 The Chain Drive The chain drive (Figure) is a way of transferring power from one place to another. It is most commonly used in bikes and motorcycles. This drive has proven from its applications that it is a strong and durable way to transfer energy. From our literature reviews we found that this is most efficient drive that we could use in our project. If kept up properly through cleaning and general inspection for problems this drive will never have to be replaced and will not break down, but it does require maintenance.

Figure 3-6 Chain Drive This figure shows how the bike and how it could be set up, and it goes into depth with how the chain drive will operate. 3.3.7 Tooth Fan Belt A tooth belt is a belt that is fitted into the gears or whatever may be turning (Figure). Teeth are sticking out of the belt and go into slot into the pulley. This allows for high rates of efficiency up to 98%. This design has proven to be efficient on pedal power. A gear combination that works well is a 52-tooth chain ring on the exercise bike connected by the chain to the flywheel that has a 16 tooth freewheels.

Tooth Fane Belt Shows a flywheel that has a toothed fan belt. 3.3.8 V belt and multi V belt A V belt is a system of pulleys where the pulleys make the belt into a V. This design is beneficial because the belt can’t slip of the track. The belt can easily attach another V belt for more power. The belt can change the way of the mechanical process and requires a small amount of maintenance. A V Belt is easy to use and long lasting. A multi-grooved belt is a belt with that has five or six v shapes next to each other (Figure 3-8). The grooves allow for flexibility on any type of pulley that doesn’t have the same grooving as the belt. The flexibility of the belt can be used to twist the belt into serpentine like patterns that could power The multiple grooves cause the belt to be wider which creates more friction. This causes heat which hurts the belt and leads to more maintenance.

V belt and multi V belt This figure shows a flywheel with a V belt and A multi V belt.

4. DECISION PHASE 4.1 Introduction The section IV describes the process of adjudicating which alternative solutions should be implemented as the best final design solution. This phase takes the alternative solutions set in section III and mathematically narrows the alternative solutions down to the final design. The method used to obtain the final design uses criteria to evaluate the benefits of each design.

4.2 Criteria Definition The following text contains the definitions of each criteria listed in the section II of this document. The defined criterions are used to adjudicate the alternative solutions that best fit the design. Multifunction is the ability to perform more than one function. This can be achieved by providing a sufficient mechanical energy to power multiple kitchen appliances (not simultaneously).

Usability is the ease of using the design in order to meet the user’s needs and requirements. Costs are the amount of money needed to purchase materials to build the bicycle. For this design project, costs are limited to $200. Aesthetics is a superficial appearance of the design. The mechanical bicycle appearance must be in accordance with an environment where it will be placed. Maintenance Time is time needed to keep the bicycle in a proper condition to perform. Maintenance time should provide the design’s various mechanical parts with the ability to withstand the force being applied against them. Safety stands for the absence of risks, injuries and accidents. Considering the project will be displayed for peoples of all ages staying at the hostel, all mechanical aspects of the bike must be safe and compatible with children. Durability is defined as the ability to perform for more than two years. Each design decision takes into consideration the durability of project’s individual mechanical parts, as well as the project as a whole.

4.3 Solutions Eight possible solutions are listed under the consideration for the final design. The detailed explanation and diagrams of these solutions are presented in Section III. These solutions are: 

Upright Bike



Exercise Bike  

   

Flywheel Gear Ratio Friction Drive Chain Drive

Tooth Fan Belt

V belt and Multi V belt

4.4 Decision Process In order to determine the best solution amongst alternative solutions, Samoa Solutions team has pursued with Delphi Decision Matrix. Criteria have been listed and each criterion has been weighted by team members individually, by scaling it from one to ten. One stood for the least important and ten for most important criteria that alternative solutions should meet. The outcome of the Delphi Decision Matrix meets the project objective. The outcome of the approach is to apply: 

Chain Drive



Friction Drive



Light Flywheel



Exercise Bike

Taking in consideration that two drives are needed for the design, it is decided that both friction and chain drives will be used. Due to the fact that most of the bicycles have a chain drive that is already installed, it is decided to apply a chain drive as a connection between the pedals and the flywheel. Although the friction drive scored 145 total points lower than the chain drive, this friction drive is easier to install for the purpose of assembling a connection between the specific kitchen appliance and the flywheel. According to the results gained from the Delphi Decision Matrix, the light flywheel scored higher than the heavy flywheel. Because the aesthetics of the drive is not crucial to the appearance of the design project in general, the use of the light flywheel for the final design is chosen over the use of the heavy flywheel. Due to the higher usability, aesthetics, safety, durability and shorter maintenance time, exercise bicycle scored 392 total points higher than the upright bicycle. In addition, use of the upright bicycle would require installation of trainers which would require additional costs. Therefore, the exercise bicycle is chosen as the final decision.

5. COST ESTIMATION MATERIAL COST S.No.

Parts

Qty

Amount

1.

Cycle

1

1500

2.

Shaft

1

50

3.

Prewheel shaft

1

100

4.

Gear

4

800

5.

Bolts

4

100

Table 5.1 Cost analysis

6. PHOTOGRAPHY

6.1 Completed prototype

7. CONCLUSION The proposed model consists of a bevel gear arrangement in it. The whole bicycle is driven by the shaft. A bevel gear arrangement is provided at the rear end of the bike and also with the pedal arrangement. When the pedal is rotated the shaft also rotates according to the speed of the pedal. The bevel gear is arranged such that the power can be transmitted from the pedal to the rear wheel easily. The bevel gear is used for 90degree power transmission. The bearing blocks are used as the support for the rotating shaft. The front bevel gear arrangement has free wheel arrangement hence when the pedal is stopped the wheel rotates with help of the free wheel.

REFERENCES

1. Werner Soedel, Vernard Foley: Ancient Catapults, Scientific American, Vol. 240, No. 3 (March 1979), p.124-125 2. Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 2, Mechanical Engineering. Cave Books, Ltd. Page 111, 165, 456–457. 3. Archibald Sharp (1896). Bicycles and Tricycles. Longmans. p. 461. ISBN 0-486-42987-3. 4. Herlihy, David V. (2004). Bicycle, the History. Yale University Press. pp. 286–287.

5. Green, Robert E. et al. (eds) (1996), Machinery's Handbook (25 ed.), New York, NY, USA: Industrial Press, ISBN 978-0-8311-2575-2. 6. Sclater, Neil. (2011). "Chain and belt devices and mechanisms." Mechanisms and Mechanical Devices Sourcebook. 5th ed. New York: McGraw Hill. pp. 262-277. ISBN 9780071704427. Drawings and designs of various drives. 7. Oxford English Dictionary (2nd ed.). Oxford University Press. 1989. "Sprocket, n. 2. b. ellipt. A sprocket-wheel, esp. that of a cycle; and (Cinematogr.), one that propels film by engaging with perforations along its edge." 8. Oxford English Dictionary (2nd ed.). Oxford University Press. 1989. "Cog, n. 1. a. One of a series of teeth or similar projections on the circumference of a wheel, or the side of a bar, etc., which, by engaging with corresponding projections on another wheel, etc., transmit or receive motion." 9. The Encyclopedia Americana: a library of universal knowledge, sprocket. pg 460 10. Oxford English Dictionary (2nd ed.). Oxford University Press. 1989. "Sprocket, n. 2. a. A projection (either forked or simple) from the rim of a wheel, engaging with the links of a chain."