Wall Clocks

INTRODUCTION

A clock is an instrument for measuring and indicating the time. The word

"clock" is derived ultimately (via Dutch, Northern French, and Medieval Latin)

from the Celtic words clagan and clocca meaning "bell". For horologists and

other specialists the term "clock" continues to mean exclusively a device with a

striking mechanism for announcing intervals of time acoustically, by ringing a

bell, a set of chimes, or a gong. A silent instrument lacking such a mechanism

has traditionally been known as a timepiece. In general usage today, however, a

"clock" refers to any device for measuring and displaying the time which, unlike a

watch, is not worn on the person.

In this document we are going see about different types of watches, its

working and mechanism, etc; and we and going to talk about the different brands

and market of watch.

Through this ITP we have implied all the knowledge that we have gained in this

semester.

Important though accuracy is to us today, it was not always so. For

several centuries, watches were extremely expensive and were status symbols

for the wealthy. The wristwatch is a 20th century invention; before then they were

worn in different ways, often as items of jewellery, and decorated accordingly.

The watch making industry has been one of constant innovation,

demanding ingenuity, dexterity, design skill, patience and good business sense –

all qualities on which the Swiss pride themselves.

The challenges continue: how to balance smallness of size with

complexity of function, or low cost with high accuracy and reliability, and how to

face up to competition from all over the world.Through this ITP we were able to

learn all the small aspects of a clock which we didn’t knew.

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History & Evolution of Clocks

Sundial:-

(16th century BC or earlier, Egypt)

In times when people's activities were limited to daylight, shadow-casting

instruments called gnomons were used to distinguish broad divisions in the

daytime. Gnomons were eventually combined with scales to produce sundials,

which allowed people to tell time by measuring the length direction of the

shadow cast by the Sun.

An Egyptian sundial from about 1500 BC provides the earliest evidence of the

division of the day into equal parts. Marks on the dial link the length of the

gnomon's shadow to a standardized unit. The ancient Egyptians also made the

first sundials resembling the round, flat one shown here. Before the division of

the day-night period into 24 equal hours became accepted practice, the number

of hours counted during any period o f daylight was held constant across the

seasons; thus, an hour in summer lasted longer than an hour in winter because

the daylight period itself was longer.

Timepieces were status symbols in ancient Greece and Rome. Donors of public

sundials had their names inscribed on the instruments, and wealthy Romans

during the reign of Augustus Caesar carried pocket sundials just over an inch in

diameter.

Sundials had to be specially made for different latitudes because the Sun's

altitude in the sky decreases at higher latitudes, producing longer shadows than

at lower latitudes. Not everyone in the ancient world realized this. A sundial

brought to Rome (41°54' N) from Catania, Sicily (37°30' N), in 263 BC told

Romans the incorrect time for almost 100 years.

Clepsydra :-

(At least 15th century BC, probably earlier)

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The drip-drip of a clepsydra was an ancient precursor of the tick-tock of modern

clocks. Clepsydras were water clocks that relied on a steadily rising or falling

water level in a container to indicate the elapse of predetermined periods of time.

Unlike sundials, clepsydras worked in cloudy weather and in the dark. But, as

with many sundials, a clepsydra's hours varied according to seasonal changes in

the period of daylight, with longer hours during summer days and winter nights.

In the clepsydra shown here, a floating pointer indicates the hour on a drum

marked with lines. Spacing between the lines on the drum varies to represent

seasonal changes in hour length. When the float tank emptied automatically at

midnight each day, the water running out of the tank through a siphon turned a

wheel that set the drum's position correctly for the new day. The float tank was

filled from a reservoir in which a constant pressure was maintained by means of

a steady water supply and a runoff outlet.

A clepsydra could not be used to "find" the time--that is, to identify the hour in

terms of the Earth's rotation. It could only measure predetermined periods, such

as the time allotted for a speech in court, or an hour whose length had been

established with an astrolabe or other "time-finding" tool.

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Astrolabe :-

(2nd century AD)

The astrolabe, or "star grasper," was a very early handheld analog computer, a

great advance in the ability to find and measure time. An astrolabe contains two

models of the celestial sphere, the rete and the tympan, which can be used

together to solve various problems of location and distance, as well as time. The

astrolabe is based on the ingenious map made by the Greek astronomer

Hipparchus about 150 BC. Hipparchus constructed his map by imagining a

perpendicular line connecting each star to a point on a plane corresponding to

the plane of the Earth's equator. The map preserved the angular relationships

among the stars and made it possible to build celestial models like the rete and

tympan. The astrolabe itself never caught on as a popular timepiece, owing in

part to the disapproval of Christian theologians who saw it as an instrument of

the devil.

An astrolabe is a set of movable plates that includes the rete, an openwork map

showing the ecliptic, or path of the sun, and the brightest stars, and the tympan,

an engraving of the principal coordinates of the celestial sphere, such as the

horizon and the meridian. Measurements made in different latitudes required the

use of different tympans. The alidade and rule were used to mark the altitudes of

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stars and to make readings from the scales engraved on the mater

(backplate).First, a bright star's altitude is measured using the alidade and the

altitude scale engraved on the back rim of the mater. Then, the rete is rotated

until the mapped star lines up with the correct altitude marker on the tympan. If

the star used is the Sun, the rete is rotated until the correct date on the ecliptic is

aligned with the altitude marker. The rule is then used to read the time from the

rim of the mater.

Candle Clock :-

(First recorded mention late 9th century AD; probably much older)

Among the earliest human inventions, candles provided another way to tell time

indoors, at night, or on a cloudy day. Like water clocks, candle clocks couldn't be

used to find the time, but the sides of candles could be marked to indicate the

passage of predetermined periods of time.

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King Alfred the Great of England has been credited with inventing graduated

candles in the late 9th century to divide his day into equal periods of study and

prayer, royal duties, and rest. Before candle clocks made an appearance in

Europe, however, it is likely that they were in use in the East, as were sundials

and water clocks.

During the Sung dynasty in China (960-1279), calibrated candles and sticks of

incense measured time. In one 18th- or 19th-century incense clock, six threads

with weights on either end were draped over an incense stick at regular intervals.

As the incense burned, the threads burned one by one and the weights dropped

to a sounding plate below. Sticks of incense with different scents might be used

at different times, so that the hours were marked by a change in fragrance.

A candle clock could be transformed into a timer by sticking a heavy nail into the

candle at the mark indicating the desired interval. When the wax surrounding the

nail melted, the nail clattered onto a plate below.

Sand Glass:-

(Before the 14th century, probably Europe)

The sandglass, with its sifting grains, embodies our perception of time's

slipperiness.

Since its invention at some unknown point prior to the 14th century, the

sandglass has worked the same way. Dry particles flow from one cuplike end of

a glass vessel to the other through a tiny passage about ten times wider than any

single particle. Powdered eggshell, marble dust, and sand have served as the

medium.

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FIG:1.1: A SAND GLASS

From the beginning, sandglasses were used to measure cooking times, as they

are today. In the past, sandglasses also figured prominently in the conduct of

legal, municipal, and intellectual affairs. When public meeting times in European

towns began to be set by clocks near the end of the 14th century, sa ndglasses

were used to assess the punctuality of attendees. Sandglasses determined the

durations of sermons, academic lectures, and even periods of torture.

Sailors used sandglasses to calculate speeds at sea. A piece of wood attached

to a rope knotted at regular intervals was thrown from the back of a moving ship.

Speed was calculated by counting the number of knots that were pulled

overboard before the sandglass ran out. With a rope knotted at intervals of 47 1/4

feet and a 28-second sandglass, a ship's speed was calculated at one nautical

mile per hour, or one knot, if the first knot in the rope appeared as the sand ran

out.

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Weight Driven Clock:-

(BC. 1270s)

The date of the first mechanical clock, as well as the name of its inventor,

remains a mystery. To pinpoint when and where the weight-driven clock was

invented, scholars have relied on indirect clues, among them an explosion in

European clock construction that began about 1309 with the clock of the Church

of St. Eustorgio in Milan.

The driving weight is suspended from a cord wound around the main gear shaft,

or barrel. As gravity pulls the weight down, the barrel turns, driving the escape

wheel.

The true innovation of the weight-driven clock was the escapement, the system

that mediated the transfer of the energy of the gravitational force acting on the

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weights to the clock's counting mechanism. The most common escapement was

the verge-and-foliot.

In a typical verge-and-foliot escapement, the weighted rope unwinds from the

barrel, turning the toothed escape wheel. Controlling the movement of the wheel

is the verge, a vertical rod with pallets at each end. When the wheel turns, the

top pallet stops it and causes the foliot, with its regulating weights, to oscillate.

This oscillation turns the verge and releases the top pallet.

The wheel advances until it is caught again by the bottom pallet, and the process

repeats itself. The actions of the escapement stabilize the power of the

gravitational force and are what produce the tick-tock of weight-driven clocks.

Spring Driven Clock:-

(Early 15th century, probably Europe)

Spring-driven clocks brought timekeeping out of the tower and into the home. In

contrast to their weight-driven predecessors, spring-driven clocks were small--

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and portable. Their openness to miniaturization led to the development of the first

watches in the late 15th century.

Despite their advantages, the new timepieces were still prone to considerable

inaccuracy. Because of this, many watches were fitted with a sundial and a

compass as a backup. At fault was the mainspring itself, the source of the clock's

power. The force exerted by the spring slackened as it unwound; as a result, the

clock ran fast when the spring was fully wound but progressively slower as it

released.

In 1674-75, the Dutch astronomer Christiaan Huygens developed a means of

controlling the release of energy from the mainspring--the spiral balance spring.

Other means had been devised for this purpose, but the advantage of the

balance spring, or hairspring, was that it performed similarly to a pendulum in a

pendulum clock. Like a pendulum's swing, the balance spring's coiling and

uncoiling has a natural periodicity that ensures the even release of energy from

the mainspring. In a modern spring-driven watch, the spring is mounted on a

balance wheel, which turns back and forth in sync with the spring's oscillations,

simultaneously rocking the pallet from side to side. The pallet controls the turning

of the gears connected to the clock's face and thereby maintains a steady

transfer of power from the mainspring to the clock's counting mechanism. While

the mainspring is being wound, a ratchet and click keep the winding action from

disturbing the watch's main gear train.

Pendulum Clock:-

(1656, Dutch astronomer Christian Huygens)

Clocks counted seconds for the first time in the second half of the 17th century.

Until the invention of the pendulum clock, mechanical clocks were unable to

count even minutes reliably.

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In the early 1580s, Galileo observed that a given pendulum took the same

amount of time to swing completely through a wide arc as it did a small arc.

Recognizing the value of applying this natural periodicity to time measurement,

Galileo began work on a mechanism to keep a pendulum in motion in 1641, the

year before he died. But it was the Dutch mathematician and astronomer

Christiaan Huygens who successfully combined the pendulum and a typical

escapement of the period to produce the first pendulum clock in 1656.

By 1671, a new type of escapement was making even greater accuracy possible

in pendulum clocks. The anchor escapement swung back and forth with the

pendulum, its pallets alternately catching and releasing the escape wheel. With

the clock's movements regulated by the natural period of the pendulum, an even

more accurate count was possible, with a loss of only a few seconds per day.

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The first pendulum clocks were weight-driven. Later versions of Huygens's

invention were powered by springs, and finally, in 1906, the first pendulum clock

driven by a self-contained electric battery started ticking.

Quartz Watch:-

(1927, W.A. Marrison and J.W. Horton)

The original quartz clock, the

invention of J.W. Horton and Warren A.

Marrison, took up the better part of a

small room. Today, quartz clocks are

built into calculators and personal

computers, and quartz watches are

everywhere. They are by far the most

popular timekeepers. Depending on

the size, shape, and vibration

frequency of its crystal, a quartz

timepiece can keep time accurately to

about one second every ten years.

FIG:QUARTZ MECHANISM

Before the invention of the quartz clock, a second had been defined as

1/86,400 of a mean solar day--that is, of the average duration of one rotation of

the Earth. The quartz clock itself did not provide a new definition of the second,

but its precision helped scientists identify irregularities in the Earth's rotation that

showed our planet was not a reliable baseline for timekeeping.

The reason that quartz clocks did not redefine the second is that the oscillations,

or vibrations, of quartz crystals begin to drift over a long period. This drifting can

be due to temperature changes, impurities in the quartz, or the cumulative effects

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of the vibrations. The new second would have to wait for the appearance of the

atomic clock.

Quartz mechanisms are highly accurate because a quartz crystal vibrates

thousands or millions of times a second when exposed to alternating electric

fields. Inside a quartz watch, electric current from the battery causes the quartz

crystal to vibrate. A microprocessor divides down the high frequency to a much

slower electrical pulse that is transmitted to the coil. The current pulsing through

the coil activates a tiny magnet, which switches rapidly back and forth in time

with the pulse. As the magnet switches back and forth, it turns a small pinion that

controls the watch's gear train, completing the conversion of the crystal's

vibration to mechanical movement.

Cesium Atomic Clock:-

(1955,

Britain's

National

Physical

Laboratory)

Inside a cesium clock, cesium-133 atoms are heated to a gas in an oven. Atoms

from the gas leave the oven in a high-velocity beam that travels toward a pair of

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magnets. The magnets separate the atoms according to whether they are

available to absorb or release energy.The atoms that can absorb energy are

directed through a microwave cavity where they are exposed to radiation with a

frequency very close to 9,192,631,770 cycles per second, which is the frequency

of the radiation emitted or absorbed by a cesium-133 atom as it shifts from one

energy state to another. Some of the atoms absorb energy from the microwaves.

These atoms are then pushed by another set of magnets toward a detector. A

servomechanism monitors a feedback loop between the detector and an

oscillator. This feedback tunes the microwave frequency until it exactly matches

the radiation frequency of the cesium atoms, maximizing the number of atoms

that reach the detector. Once the microwave frequency is locked into the cesium

atoms' frequency, it is then divided down to a frequency that can be used to mark

time accurately to a few billionths of a second.The principle underlying the

cesium clock is that all atoms of cesium-133 are identical, and when they absorb

or release energy, the radiation produced by individual atoms has exactly the

same frequency, which makes the atoms perfect timepieces. Whereas seconds

counted by the Earth's rotation are never identical, atomic seconds are--always.

In 1967, the 13th General Conference of Weights and Measures formally

redefined the second as "9,192,631,770 periods of the radiation corresponding to

the transition between the two hyperfine levels of the ground state of the cesium-

133 atom." Ever more precise timekeeping is not simply a pet project of science.

Without the atomic clock, the vast, complex networks coordinating electrical

power distribution, communications, and transportation throughout the world

would not be possible.

Invention of Clocks:-

In 1656, 'Christian Huygens' (Dutch scientist), made the first 'Pendulum clock',

with a mechanism using a 'natural' period of oscillation.

In 1657 he developed the balance wheel and spring mechanism of the clocks

which is even found in the present clocks and wrist watches.

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Eli Terry Sr. was the first person to receive the patent for a shelf clock

mechanism in 1790.

He introduced the mass production of mechanical clocks affordable for a

common man.

Different types of Clocks

ANALOG CLOCKS:-

Analog clocks usually indicate time using angles. The most common clock

face uses a fixed numbered dial or dials and

moving hand or hands.

It usually has a circular scale of 12

hours, which can also serve as a scale of 60

minutes, and often also as a scale of 60

seconds—though many other styles and

designs have been used throughout the years,

including dials divided into 6, 8, 10, and 24

hours. Of these alternative versions, the 24

hour analog dial is the main type in use today.

FIG: AN ANALOG CLOCK

The 10-hour clock was briefly popular during the French Revolution, when

the metric system was applied to time measurement, and an Italian 6 hour clock

was developed in the 18th century, presumably to save power (a clock or watch

chiming 24 times uses more power).

Types of Analog Clocks

Alarm Clock

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The first mechanical clocks were made in the 14th century, and were large

monumental clocks. Household clocks were in use by 1620 and some of them

had alarm mechanisms. The alarm is simple in concept, typically having a cam

that rotates every 12 hours. It has a notch into which a lever can fall, releasing a

train of gears that drives a hammer, which repeatedly hits a bell until it runs down

or is shut off (many alarms have no shutoff control).

The earliest alarm clock I found reference to is a German iron wall clock

with a bronze bell, probably made in Nuremberg in the 15th century. This clock is

19 inches tall and of open framework construction. It needed to hang high on the

wall to make room for the driving weight to fall. Other alarm clocks from the

1500's are in existence. See “The Clockwork Universe, German Clocks and

Automata 1550 - 1650,” Maurice and Mayr, 1980, Smithsonian, Neale Watson

Academic Publications, New York.

Pendulum Clocks:-

From its invention in 1656 by Christiaan Huygens

until the 1930s, the pendulum clock was the

world's most accurate timekeeper, accounting for

its widespread use. Pendulum clocks cannot

operate in vehicles; the motion and accelerations

of the vehicle will affect the motion of the

pendulum, causing inaccuracies. They are now

kept mostly for their decorative and antique value.

The pendulum clock was invented and

patented by Christiaan Huygens in 1656, inspired

by the investigations of pendulums by Galileo

Galilei. Galileo had the idea for a pendulum clock in 1637, partly constructed by

his son in 1649, but they didn't live to finish it. The introduction of the pendulum

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increased the accuracy of clocks by a factor of 100, leading to their rapid spread

as existing clocks were retrofitted with pendulums.

Cuckoo Clocks:-

A cuckoo clock is a clock, typically pendulum driven, that strikes the hours using

small bellows and pipes that imitate the call of the Common Cuckoo in addition to

striking a wire gong. The mechanism to

produce the cuckoo call was installed in

almost every kind of cuckoo clock since the

middle of the eighteenth century and has

remained almost without variation until the

present.

Cuckoo clocks are almost always

weight driven; a very few are spring driven.

The weights are made of cast iron in a pine

cone shape. The "cuc-koo" sound of a

cuckoo clock is created by two tiny gedackt

(pipes) in the clock, with bellows attached to their bottoms. The clock's

mechanism activates the bellows to send a puff of air into each pipe alternately

when the clock strikes.

In recent years, quartz battery-powered cuckoo clocks have been

available.

Talking Clocks:-

A talking clock (also known as a "speaking clock" or "auditory clock") is a

timekeeping device that presents the time as sounds. It may present the time

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solely as sounds, such as a phone-based time service (see Speaking clock) or a

clock for the hearing impaired, or may have a sound feature in addition to an

analog or digital face.

Talking clocks have found a natural home as an assistive technology for

the visually impaired. There are over 150 tabletop clocks and 50 types of

watches which include an auditory function. However, their aid is somewhat

limited, as most of them tend to announce the time only at the top of the hour or

the press of a button. Nevertheless, to press the button, one must be able to find

the clock. To address these limitations, one manufacturer produced a clock that

would announce the time upon detecting a user's whistling signal, but it is no

longer manufactured.

Other Types of Analog Clocks:-

Astronomical Clocks

Grandfather Clocks

Tide Clocks

Stop Watch

DIGITAL CLOCKS:-

Digital clocks display a numeric representation of time. Two numeric display

formats are commonly used on digital clocks:

the 24-hour notation with hours ranging 00–23;

the 12-hour notation with AM/PM indicator, with hours indicated as 12AM,

followed by 1AM–11AM, followed by 12PM, followed by 1PM–11PM (a

notation mostly used in the United States).

Most digital clocks use an LCD or LED display; many other display technologies

are used as well (cathode ray tubes, nixie tubes, etc.). After a reset, battery

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change or power failure, digital clocks without a backup battery or capacitor

either start counting from 00:00, or stay at 00:00, often with blinking digits

indicating that time needs to be set. Some newer clocks will actually reset

themselves based on radio or Internet time servers that are tuned to national

atomic clocks. Since the release of digital clocks in the mainstream, the use of

analog clocks has dropped dramatically.

Parts Of A Clock

1. Winding and Hand-Setting

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2. The Hour, Minute and Second Hands’ motion parts

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3. Balance

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4. Escapement

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5. Mainspring Barrel

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6. The Wheel Train

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7. Wheels and Pinions

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8. Dials:-

Dials are basically the base of the

clocks on which the numbers are

written and the movement hands

rotate over it.

Dials can be of any shape and types

based on materials used:-

Ceramics

Metals

Wood

Glass

9. Bezels and Rings:-

Bezels and Rings are used for the

better look of the clock in the interior

as well as exterior part of it.

These also vary in shape, size and

the materials used.

They are mainly used for the design

purpose of the clock.

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10. Hands:-

Hands include the Minute, Hour and Second hands which shows us the time. X

They are of different types based on the design and nature of clocks.

11. Numerals and Dots:-

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Numerals or Dots can be found in each and every clocks.They may be atached

with the ring or can be free.They are also of various types based on the design.

Materials Used

1) PLASTICS-

The extraordinary combination of

performance and processing flexibility allows

plastics to be used in numerous applications

ranging from inexpensive disposable items to

expensive components.

The electrical insulation, color, strength and

high speed molding qualities Resistance

to chemicals makes polymers the perfect

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container for cleaning products and other caustic substances are some of the

properties of plastics.

AdvantagesPlastics provide the following advantages for product designers and

manufacturers:

Stiffness or Ductility

Low Weight

High Manufacturing Throughput

High Reproducibility of Parts

Electrical Insulation Design Flexibility

High Strength and Toughness

Corrosion Resistance

Reduced Manufacturing Costs

Almost Any Color or Surface Texture Waterproof

2) Acrylonitrile Butadiene Styrene - ABS Platin

Polymer Type- Thermoplastic

PHYSICAL PROPERTIES

Property Value

Density (g/cm3) 1.06

Surface Hardness RR107

Tensile Strength (MPa) 42

Flexural Modulus (GPa) 2.4

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Notched Izod (kJ/m) 0.4

Linear Expansion  (/°C x 10-5) 8

Elongation at Break (%) 8

Strain at Yield (%) 2.5

Max. Operating Temp. (°C) 70

Water Absorption (%) 0.3

Oxygen Index (%) 19

Flammability UL94 HB

Volume Resistivity (log ohm.cm) 16

Dielectric Strength (MV/m) 20

Dissipation Factor 1kHz 0.008

Dielectric Constant 1kHz 2.7

HDT @ 0.45 MPa (°C) 98

HDT @ 1.80 MPa (°C) 89

Material. Drying hrs @ (°C) 4 @ 90

Melting Temp. Range (°C) 250 - 285

Mould Shrinkage (%) 0.6

Mould Temp. Range (°C) 40 -  80

Advantages

Can be electroplated to give parts with the more decorative finish of

metals such as Chrome Gold, Silver and Brass. The plating can increase

the rigidity of a molding as well as scratch resistance. The metal layer

screens radio waves and conducts electricity

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DisadvantagesTemperature profile and mould surface temperatures need to be

kept higher than for standard ABS grades. This is in order to ensure good

surface finish for subsequent electroplating & also to minimize moulded in

stresses. Mould release agents should not be used as they affect plating

behavior. Regrind should not be used for items to be electroplated

because of possible flaws in surface finish.

3) CHROMIUM PLATED WITH GOLD

Chemical Formula-Cr

Physical Properties

Chemical properties

Modulus of elasticity in tension   200 GPa

Poisson's ratio   0.32

Thermal conductivity 100°C 30.0 W/m.K

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Property Value

Density 8.44 g/cm3

Melting Point 916°C

Modulus of Elasticity 103.4 GPa

Thermal Conductivity 116 W / m.K at 20°C

Thermal Expansion 20.5x10-6 /°C at 20-300°C

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  500°C 40.0 W/m.K

Electrical resistivity   678 nÙm

Specific thermal capacity   478 J/kg.K

Co-efficient of thermal expansion 1-100°C 11.1 ìm/mK

  0-300°C 11.7 ìm/mK

  0-500°C 12.3 ìm/mK

Melting range   1430-1510°C

Relative permeability   Ferromagnetic

AdvantagesPlastics provide the following advantages for product designers and

Manufacturers:

Stiffness or Ductility

Low Weight

High Manufacturing Throughput

High Reproducibility of Parts

Electrical Insulation Design Flexibility

Corrosion Resistance

Reduced Manufacturing Costs Almost Any Color or Surface Texture Waterproof.

4. STAINLESS STEEL

Physical properties

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Advantages

Atmospheric corrosion resistance Cutting Forming Machining Weld ability Coating and Painting

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Density 7740 kg/m3

Modulus of elasticity in tension

200 GPa

Poisson's ratio 0.32

Thermal conductivity 100°C 30.0 W/m.K

500°C 40.0 W/m.K

Electrical resistivity 678 nÙm

Specific thermal capacity

478 J/kg.K

Co-efficient of thermal expansion

1-100°C 11.1 ìm/mK

0-300°C 11.7 ìm/mK

0-500°C 12.3 ìm/mK

Melting range 1430-1510°C

Relative permeability Ferromagnetic

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Common Defects:-

1. Normal wear and tear

2. Damage to watch glass and strap / bracelet.

3. Gold plating and other metal finishes damaged due to exposure to

chemical solvents, commercial cleaners, detergents etc.

4. Plating damage due to scratches, dents or any other physical damage.

5. Moisture entry off on the underside of the metal strap or bracelet

6. Failure of power cells

Handling and care of your watch:-

1. Protect your watch from moisture and extreme heat.

2. Get the watch serviced periodically.

3. Avoid exposure to strong magnetic fields and voltage stabilizers.

4. If you are not using your quartz watch for a long time then pull the crown

to the utmost to prevent the consumption of battery.

5. Don’t open the watch unnecessarily

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How does a Clock work?

Mechanical Watch

Working of the Cannon Pinion, Hour Wheel, Minute Wheel and

Wheel Pinions

  The illustration above shows the motion works of a center-

seconds watch. (1) The fourth wheel pinion, which carries

the seconds hand. (2) The center wheel pinion, which

carries the cannon pinion. (3) The cannon pinion, which

carries the minutes hand. (4) the hour wheel, which carries

the hour hand.

 

The second illustration diagrams the power flow from

movement to hands. (A) The movement plate. (B) The

center wheel. (C) The fourth wheel. (D) The cannon pinion.

(E) The hour wheel. (F) The minute wheel. You can follow

the power flow with the red numbers, 1 through 8.

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Working of the Balance Cock and Balance Assembly

The entire balance cock

and balance assembly is

illustrated. (1) The

balance cock. (2) The

anti-shock unit for the

upper balance pivot. (3)

The regulator to control

rate. (4) The balance spring. (5) The balance wheel. (6) The hairspring

stud, which is held in the stud holder of the balance cock with the small set

screw. (7) The balance staff.

Working of the Balance Wheel

The screws around the rim of the

balance wheel are used to adjust

the poise ("balance") of the

balance wheel, and, in split

balances with steel balance

springs, the temperature

compensation. Such a split

balance is made of layered steel

and brass and is cut at two points

near the balance arms. (1) The

impulse roller. (2) The safety roller. (3) The lower balance pivot . (4) The

impulse jewel (or impulse pin). (5) The balance spring (in this case an

overcoil design). (6) The alignment pins used to locate the balance cock

accurately on the main plate.

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Winding

  FIG

The positioning of the keyless-works parts for winding is shown in the green

numbering. (1) The crown is pushed in, (2) the setting lever swings in, (3) the

opposite end of the setting lever swings out allowing (4) the return lever to (5)

slide the clutch into engagement with the winding pinion.

The red arrows show the power flow from (1) the stem, to (2) and (3) the clutch,

to (4) the winding pinion, and then on to the crown gear and mainspring barrel

(blue arrow).

During hand setting, all parts move in the direction opposite the green arrows.

This brings the clutch into contact with the intermediate wheel, which drives the

minute wheel, cannon pinion, and hour wheel.

The keyless works can be among the most beautiful parts of the mechanical

watch.

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Working of Click

During winding, the mainspring barrel is

stationary and the ratchet wheel winds

the inner end of the mainspring counter-

clockwise around the arbor in the center

of the barrel. When the movement is

running, the ratchet wheel is stationary

and the outer end of the spring rotates

the barrel clockwise. The barrel (and

integral main wheel) drives the center

wheel pinion gear.

While the movement itself prevents the mainspring unwinding from the outer

(barrel) end, the ratchet prevents unwinding from the inner (arbor) end.

FIG

The click is thus designed to prevent the ratchet wheel from rotating clockwise

while allowing counter-clockwise movement (for winding).

The click spring maintains tension on the click in the clockwise direction. The

very typical two-toothed click design, illustrated, prevents the click from holding

the mainspring at absolute full tension. When the crown is released after winding,

the click is rocked counter-clockwise (against the click spring) by the large tooth

and the small tooth engages and locks the ratchet wheel. This allows the ratchet

wheel and arbor to rotate slightly clockwise. This action relieves a bit of tension in

the mainspring and prevents excessive tension that might cause the transmission

of too much power to the gear train and, thus, knocking of the balance wheel.

Working of the Conical Pivot and Jewel

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FIG

The conical pivot (1) requires two jewels for a bearing, a cap jewel (5) and

pierced jewel (6). Unlike the cylindrical pivot, the conical pivot has no "shoulder"

and uses the cap jewel to determine end-shake of the wheel pinion (3). This

arrangement provides lower friction than the single-jewel cylindrical pivot

arrangement. Generally, friction on the conical pivot occurs only at the tip of the

pinion on the lower cap jewel (3) or, in a vertical position of the watch (a

horizontal position of the pinion) on the thin edges of the holes in the two pierced

jewels (6). The conical pivot is usually used on the balance wheel and,

sometimes, on the escape wheel. The balance (and, when provided, escape

wheel) anti-shock assembly uses a conical pivot with cap and pierced jewel.

Working of the Cylindrical Pivot and Jewel

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The cylindrical pivot (1) has the advantage of simplicity, robustness, and low

cost. The friction of the cylindrical pivot is relatively high compared to the two-

jewel arrangement used with the conical pivot. This friction results from the

relatively thick jewel hole (2) and the pivot shoulder rubbing on the backside of

the jewel (3) on the lower pivot (depending on the position of the watch).

The cylindrical pivot is used for the mainspring barrel and gear train of the watch.

The balance wheel usually uses a conical pivot, as does the escape wheel in

many finer watches.

2. Quartz clock

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In quartz watch the oscillator is a quartz crystal, which has the property

that it vibrates in the presence of an electric field. The high frequency of the

vibrations means that a quartz timekeeper is very accurate – to within about one

minute a year.

FIG

The quartz is used in an electrical circuit, where its rate of oscillation is carefully

regulated. Although the properties of quartz had been discovered towards the

end of the 19th century (and were used, for example, in early radio sets), it was

not until the 1960s that it became possible to manufacture integrated circuits

small enough to be used in wristwatches.

Where the source of energy in a mechanical watch is the spring, in a quartz

watch it is a miniature battery, which lasts for several years.

Quartz crystals have been in regular use for many years to give an

accurate frequency for all radio transmitters, radio receivers and computers.

Their accuracy comes from an amazing set of coincidences: Quartz -- which is

silicon dioxide like most sand -- is unaffected by most solvents and remains

crystalline to hundreds of degrees Fahrenheit. The property that makes it an

electronic miracle is the fact that, when compressed or bent, it generates a

charge or voltage on its surface. This is a fairly common phenomenon called the

piezoelectric effect. In the same way, if a voltage is applied, quartz will bend or

change its shape very slightly. If a bell were shaped by grinding a single crystal

of quartz, it would ring for minutes after being tapped. Almost no energy is lost in

the material. A quartz bell -- if shaped in the right direction to the crystalline axis

-- will have an oscillating voltage on its surface, and the rate of oscillation is

unaffected by temperature. If the surface voltage on the crystal is picked off with

plated electrodes and amplified by a transistor or integrated circuit, it can be re-

applied to the bell to keep it ringing.

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A quartz bell could be made, but it is not the best shape because too

much energy is coupled to the air. The best shapes are a straight bar or a disk. A

bar has the advantage of keeping the same frequency provided the ratio of

length to width remains the same. A quartz bar can be tiny and oscillate at a

relatively low frequency -- 32 kilohertz (KHz) is usually chosen for watches not

only for size, but also because the circuits that divide down from the crystal

frequency to the few pulses per second for the display need more power for

higher frequencies. Power was a big problem for early watches, and the Swiss

spent millions trying to bring forward integrated-circuit technology to divide down

from the 1 to 2 MHz the more stable disk crystals generate.

The major difference between good and indifferent time keeping is the initial

frequency accuracy and the precision of the angle of cut of the quartz sheet with

respect to the crystalline axis. The amount of contamination that is allowed to get

through the encapsulation to the crystal surface inside the watch can also affect

the accuracy.

The electronics of the watch initially amplifies noise at the crystal frequency. This

builds or regenerates into oscillation -- it starts the crystal ringing. The output of

the watch crystal oscillator is then converted to pulses suitable for the digital

circuits. These divide the crystal's frequency down and then translate it into the

proper format for the display.

How to Assemble Different Parts Of A Clock

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Wall Clocks

FIG

Drill a hole through the material you are working with, attach a hanger and

rubber washer to movement.

After inserting movement shaft through hole of dial, screw barrel nut on

firmly.

Gently press minute hand onto shaft 12:00 position.

Gently press minute hand onto shaft also at 12:00 position.

Press second hand gently onto pin inside movement shaft.

Set correct time by turning wheel on back of movement.

Insert correct size battery.

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Pollution & Environmental Concern

Causes of Pollution:-

• Parts are non-recyclable.

• Radium in dial before inserting

requires licking which causes

radiation exposure.

• Batteries used

• Waste thrown by manufacturing

units

Developments made to stop Pollution:-

• Recyclable parts being made.

• Self winding and Eco-Drive watches being used.

• Manufacturing units installing waste management units.

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Market Watch

MOST PREFFERED CLOCK BRANDS IN INDIA

S. No BRANDS

1 Ajanta

2 Samay

3 Sonam

4 Hmt

5 Alwyn

6 Rochees

7 Q & Q

Most preferred Foreign Brands:-

S.No BRANDS

1 Citizen

2 Chelsea

3 Jonathon Knowles & Co

4 Fossil

5 Swiss Army

6 Movado

7 Howard Miller

8 4D

9 Alessi

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Designer Clocks:-

Designers like FURNI are famous for their unique designs.

Brands like FOSSIL and MOVADO also produces fashionable clocks for interior

décor.

Most Preferred Brands:-

For Lower class : Non-Branded Clocks (Produced locally)

For Middle class : Brands like Ajanta, Samay etc.

Price Range: Rs. 300- Rs 3000.

For Higher class : Brands like Chelsea, Fossil, Movado etc.

Price Range: More than Rs. 6000.

Research and developments

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Wall Clocks

The mainsprings of present-day mechanical clocks are made from metals that

resist breakage and rust. Synthetics have replaced precious stones in jeweled

bearings. Cases have been perfected that seal out both dust and moisture.

Cases have been perfected that seal out both dust and moisture.

The Braille clocks for the blind, which has sturdy hands not covered with a

crystal, and raised dots on the dial to mark the hours. New sources of power,

such as sunlight, body heat, and atomic energy, are being investigated in current

horological research.

Newly Invented Watches:-

Inspiration Clocks

Info Clocks

Image Reminder Clocks

Shop Clocks

Mood Clocks

Digital Wallet Clocks

Webcam Clocks

Baby Monitor Clocks

Landmark Reminder Clock

Clocks are made from metals that resist breakage and rust .

Cases have been perfected that seal out both dust and moisture.

The Braille clocks for the blind, which has sturdy hands not covered with a

crystal, and raised dots on the dial to mark the hours.

New sources of power, such as sunlight, body heat, and atomic energy,

are being investigated in current horological research.

The most recent clock developed is the ATOMIC CLOCKS which help in

maintaining the accurate time up to the micro seconds.

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Wall Clocks

Future Clocks

Scratch Resistance Technology:-

The crystal is the clear covering over the face and hands of the clocks. The

material used in making the crystal determines its scratch resistance. These

types of crystals are generally used in clocks:

An acrylic plastic crystal is the least scratch-resistant, although shallow

scratches can be polished out.

A mineral crystal is made up of several mineral elements that are

manufactured and treated by heat procedures to create a hardness

that helps in resisting scratches.

A sapphire crystal is the most durable and scratch-resistant crystal. It

is approximately 3 times harder than a mineral crystal and 20 times

harder than acrylic plastic crystals.

We recommend that, at a minimum, the clock should have a mineral crystal.

Eco Drive Clocks:-

These new Eco-Drive clocks will never need to have the battery replaced.

Sunlight and any artificial light are absorbed through the crystal and dial. A solar

cell beneath the dial converts any form of light into electrical energy to power the

watch. With regular exposure to light, Eco-Drive continuously recharges itself for

a lifetime of use. Eco-Drive's revolutionary lithium-ion rechargeable battery stores

enough energy to power the watch for an astonishing six months (even in the

dark.) Since Eco-Drive technology is based on harnessing the power of light - a

truly renewable energy source - and no replacement batteries are ever needed,

Eco-Drive is environmentally friendly. It's the green way to tell time. No batteries

to change.

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Wall Clocks

Water Resistance Technology:-

Most clocks have some sort of water-resistance. If you want to protect

your clock from water, basic water-resistance is probably enough. For intensive

contact with water, such as taking a shower, bathing, or swimming, a water-

resistance of 50 feet or more is recommended. For athletic water activity such as

diving or snorkelling, our experts suggest a water-resistance of 100 feet or more,

preferably with a screw-down crown. A screw-down crown seals the internal case

of the watch and prevents air and moisture from penetrating the watch through

the crown and stem housing (usually located at the 3 o'clock position). A clock

bearing the inscription 'water-resistant' on its case back can handle light

moisture, such as a light rainstorm or hand washing, but should not be worn for

swimming or diving. If the watch can be submerged in water, it must state at what

depth it maintains its water-resistance, i.e. 50 meters (165 feet) or more on most

sport watches. Below 200 meters, the watch may be used for skin diving and

even scuba diving depending upon the indicated depths. Sometimes water-

resistance is measured in atmospheres (ATM). An ATM is equal to 10 meters of

water pressure (some European-made watches use the term 'bar' instead).

Straps other than metal bracelets may not be water-resistant. New water-

resistant versions of nylon, rubber, and other synthetics are a trend in sport

watches.

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Wall Clocks

Conclusion

From this Integrated Term Project we understood the application of the

different modules we had come across in this semester. Also, we got an

opportunity to do an in-depth study on the wrist watches which helped us in

getting a lot of information about the product.

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Wall Clocks

Glossary

ANALOG

     An analog clock is simply a clock that has "hands".  Analog watches may

have a second hand which moves in a continuous motion or no second hand at

all.  On some style clocks when the second hand moves at two second intervals

it is a signal that the battery is low and needs to be replaced.

 

DIGITAL

     A digital clocks is one in which the time is displayed in numbers

     An "LCD" clock uses a liquid crystal display to display to display the time.  The

numbers are usually gray or black on a lighter background.

     An "LED" clock uses a light emitting diode to display the time.  This style

watch usually has a button that you press to see the time and the numbers are

bright red.

QUARTZ

     A quartz clock is the most common watch in the marketplace today, it runs on

a battery.  A tiny quartz crystal in the watch vibrates at a very stable frequency

which keeps the time instead of the traditional mechanical movement.

MECHANICAL

     A mechanical clock operates using a series of gears.  A spring in the watch is

wound to power the gears.  A jeweled watch uses gems such as rubies at points

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of friction inside the "movement."  A watch containing 17 jewels is considered a

fine watch.

AUTOMATIC

     An automatic clock is a self winding watch.  The watch is designed so the

motion of your wrist continually winds the watch when you wear it.

MOON

     A moon clock has a second dial that rotates behind the regular dial which has

an opening in it.  The rotating dial that changes as the dial rotates showing the

various phases of the moon or the sun during the day and the moon at night.

CHRONOMETER

     A watch that conforms to strict standards of accuracy set by an official

institute COSC Contrôle Officiel Suisse des Chronomètres in Switzerland. Not to

be confused with chronograph.

 SOME COMMON WATCH TERMS:

ANALOG

A timepiece with dial, hands and numbers or markers indicating the 12 hour time

span. The standard clock design.

ANTI- MAGNETIC

A clock which is designed to resist magnetic fields such as those caused by

electric motors.

BASE METAL

Any non-precious metal.

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BEZEL

The ring around the dial of a clock that can hold the crystal in place. In some

watches (e.g., diver's watches) this can be rotated to show elapsed time as other

functions.

CABOCHON CROWN

A rounded semi-precious stone or synthetic material usually black, fitted into the

watch crown as an ornament.

CALENDAR

A clock feature that shows the date and sometimes the day of the week and the

month. It can be displayed through a cut-out window in the dial, as a sub-dial with

small hands indicating the day/ date feature or by digital readout.

CALIBRE

The size and factory number of a particular clock movement. The number

denoting the calibre is displayed on the case back of a Pulsar watch and is the

first four digits before the hyphen in an eight-digit number.

CASE

This is the protective covering surrounding a clock movement. Primarily it is

made from base metal, stainless steel, gold, etc. and includes a bezel, back and

crystal. The quality of the material dictates the appearance and the value of the

clock.

CHRONOGRAPH

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Another name for stopclock. This feature allows one to record the time of an

event starting from zero, and to stop and start or go back to zero at the push of a

button.

DIAL

The plate set behind the hands and over the movement of a clock designed with

numbers or markers indicating the time divisions.

DIGITAL

Any clock that shows the time in numbers instead of by hands on a dial. The

numbers appear in LCD (liquid crystal display) which shows a continuous reading

or in LED (light-emitting diode) which shows time at the push of a button.

DUAL TIME INDICATOR

Displays time in two different time zones.

ELECTROPLATING PROCESS

Process of covering metal articles with a film of other metals. The article is

immersed in a chemical solution; electric current (D.C.) flows through the solution

from a piece of metal (anode) to the article (cathode), depositing metal thereon

by electrolysis. Metals which can be used for plating are: 1) gold-a precious

metal generally yellow in color; 2) chrome-can be white or black; 3) palladium-a

precious metal, generally white; 4) ruthenium-also a precious metal but usually

gray.

HANDS

The pointing device anchored at the center and circling around the dial indicating

the hours, minutes, seconds and any other special features of the watch.

Alpha Hands: A slightly tapered hand.

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Baton Hands: A narrow hand sometimes referred to as a stick hand. 

Dauphine Hands: A wide, tapered hand with a facet at the center running the

length of the hand.

Luminous Hands: Hands made of skeleton form with the opening filled by a

luminous material.

Skeleton Hands: Cut-out hands showing only the frame.

LUMINOUS

Self illuminating paint used on hands and markers.

QUARTZ

A natural or commercially synthesized silicon dioxide crystal. Used in "quartz

analog" or solid state digital watches. When activated by a battery or solar power,

the thin silver of crystal very predictably vibrates at an extremely high frequency

(32,768 times per second) thus providing very accurate time keeping. The main

components are: an Electronic Circuit Block (Quartz Oscillator and CMOS-IC)

and the Mechanical Block (step motor, gear train, hands) and a battery.

RATCHET BEZEL RING

A bezel ring which can turn either one way (counter clockwise) or both ways and

generally clicks into

position.                                                                                                                    

                                              

SAPPHIRE CRYSTAL

Scratch resistant crystal.

SCREW DOWN LOCKING CROWN

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Wall Clocks

A crown which aids water resistance by sealing the crown against the case. The

seal is achieved by the matching of a threaded pipe on the case with the crown's

internal threads and gasketing while twisting the crown to lock it into place.

SELF-WINDING

An automatic clock that winds itself from the motion that occurs when it is worn

on the wrist.

SHOCK RESISTANT

For a clock to be called shock resistant it must be able to be dropped 39 inches

onto a hard wood floor without any significant effect on the operation of the

watch.

SOLAR

Light is converted into energy by a solar panel. This energy can be stored for up

to six months in a rechargeable battery.

SOLID STATE

A timepiece with no moving parts. All digital watches are 100%solid state. Analog

watches combine solid state circuits with moving parts.

STRAP

A clock band made of leather, plastic or fabric.

SUN/ MOON INDICATOR

A wheel on a clock partially shown through a cut-out window indicating a sun and

moon on a 24-hour basis.

TITANIUM

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Wall Clocks

Titanium is a space age metal that is twice as strong and half as light as stainless

steel. It is also non-allergenic, extremely resistant to salt water and other forms of

corrosion, and able to withstand extreme temperatures.

WATER RESISTANT

A water resistant clock will withstand water pressure up to a depth of 100 feet.

This is the equivalent of three atmospheres.  The use of the term "Water Proof" is

expressly forbidden under the F.T.C. guidelines. A term that may be used if a

watch is sufficiently impervious to water or moisture so that at the point of

purchase, that watch could successfully withstand tests as specified by the

Federal Trade Commission

58