Cranes

A crane is a tower or derrick that is equipped with
cables and pulleys that are used to lift and lower
material.  They are commonly used in the construction
industry and in the manufacturing of heavy equipment.
Cranes for construction are normally temporary
structures, either fixed to the ground or mounted
on a purpose built vehicle.

They can either be controlled from an operator in
a cab that travels along with the crane, by a push
button pendant control station, or by radio type
controls.  The crane operator is ultimately responsible
for the safety of the crews and the crane.

Medieval cranes
Cranes of the Middle Ages were used to build the
cathedrals of Europe.  The crane was fixed on top
of a wall as it was being constructed and was
powered by men that ran inside of two large wheels
on each side.  Cranes were also used in medieval ports
and in shipyards.

Mobile cranes
The most basic type of crane consists of a steel
truss or telescopic boom mounted on a mobile platform,
which could be a rail, wheeled, or even on a cat
truck.  The boom is hinged at the bottom and can
be either raised or lowered by cables or hydraulic
cylinders.

Telescopic crane
This type of crane offers a boom that consists of
a number of tubes fitted one inside of the other.
A hydraulic mechanism extends or retracts the
tubes to increase or decrease the length of the
boom.

Tower crane
The tower crane is a modern form of a balance
crane.  When fixed to the ground, tower cranes
will often give the best combination of height and
lifting capacity and are also used when constructing
tall buildings.

Truck mounted crane
Cranes mounted on a rubber tire truck will provide
great mobility.  Outriggers that extend vertically
or horizontally are used to level and stabilize
the crane during hoisting.

Rough terrain crane
A crane that is mounted on an undercarriage with
four rubber tires, designed for operations off
road.  The outriggers extend vertically and
horizontally to level and stabilize the crane when
hoisting.  These types of cranes are single engine
machines where the same engine is used for powering
the undercarriage as it is for powering the
crane.  In these types of cranes, the engine is
normally mounted in the undercarriage rather than
in the upper portion.

Loader crane
A loader crane is a hydraulically powered articulated
arm fitted to a trailer, used to load equipment
onto a trailer.  The numerous sections can be
folded into a small space when the crane isn't in
use.

Overhead crane
Also refered to as a suspended crane, this type
is normally used in a factory, with some of them
being able to lift very heavy loads. The hoist is
set on a trolley which will move in one direction
along one or two beams, which move at angles to
that direction along elevated or ground level
tracks, often mounted along the side of an assembly
area.

In the excavation world, cranes are used to move
equipment or machinery.  Cranes can quickly and
easily move machinery into trenches or down steep
hills, or even pipe.  There are many types of
cranes available, serving everything from
excavation to road work.

Cranes are also beneficial to building bridges or
construction.  For many years, cranes have proven
to be an asset to the industry of construction
and excavating.  Crane operators make really good
money, no matter what type of crane they are
operating.

Drag Line Excavator

Drag line excavator systems are heavy machinery that
is used in civil engineering, surface mining, and
excavation.  With civil engineering, the smaller
types are used for road and port construction.  The
larger types of drag line excavators are used in
strip mining operations to extract coal.  These are
among the largest types of mobile equipment and
weigh upwards of 10,000 tons!

The drag line excavator bucket system consists of
a large bucket that is suspended from a boom.  The
bucket is moved by a number of chains and ropes.  The
hoisting rope, which is powered by either a large
diesel or electric motor, will support the bucket
and hoist coupler assembly from the boom.  The
drag rope on the assembly is used to draw the bucket
assembly horizontally.  Through skillful maneuvering
of the hoist and drag rope, the bucket can be
controlled for many different types of operations.

Operation
With a typical excavation cycle, the bucket is
positioned high above the material that is being
excavated.  The bucket is then lowered down and the
drag rope is drawn so that the bucket is dragged
along the materials surface.  Using the hoist rope,
the bucket is then lifted.  A swing operation is
then performed in order to move the bucket to the
place where the material is going to be dropped.
The drag rope is then released which will cause the
bucket to tilt, making the material in the bucket
fall down, which is commonly known as a dump operation.

With smaller drag line excavators, the bucket is
thrown by winding up the jib then releasing a
clutch on the drag cable, which swings the bucket
like a pendulum.  Skillful operators can make the
bucket land about 1/2 the length of the jib further
away than if it had just been spun or dropped.

Limitations
The limitations of drag line excavators are the
height and length of their boom, as this limits
where the drag line can dump waste material.  Being
inherent with their construction, the drag line
is most effective when excavating material
below the level of their tracks.  Drag lines
aren't suitable for loading piled up material.

Despite their limitations and high capital cost,
drag line excavators remain very popular with
several mines, due to their very low waste removal
cost, performance, and reliability.

They also have different cutting sequences.  The
first is the side casting method which uses
offest benches.  This method involves throwing
the overburden sideways onto blasted material to
make a bench.

The second method is a key pass.  This pass will
cut a key at the toe of the new highwall and will
also shift the bench further towards the low
wall.  This can also require a chopping pass if the
wall is blocky.  A chopping pass will involve
the bucket being dropped down onto an angled
highwall to scale the surface.

The next method is the slowest, known as the
blocks pass.  This method will however, move the
most material.  The blocks pass involves using
the key to access the bottom of the material to
lift it up to spoil or to an elevated bench
level.  If required, the final cut is a pull
back, which pulls the material back further to
the low wall side.

For construction, mining, or excavation, drag line
excavators are great to have.  They can move even
the biggest of material, which is great for deep
holes in the ground.  If you've been looking for a
great way to maximize mining or excavation productivity,
the drag line excavator is just what you need.

Porsche the beginning

It`s hard to say exactly which is the beginning of Porsche
story. It could be in 1950, when the famous Max Hoffman
introduced the Porsche 356 to the United States. Or in 1948
when the first automobile to bear the name Porsche was introduced.
But in order to understand Porsche’s heritage and its philosophy
we need to go back to 1875, when, in September, at the home
of a tinsmith in the Bohemian village of Haffersdorf, a son was
born. His name was Ferdinand Porsche.

Since his adolescence, Ferdinand Porsche showed glimpses of
technical genius: at the age of 18, he wired family's home for
electricity in 1893. Still, he didn’t show many signs of disciplined
engineering skills that will eventually become his trademark. Even
if the “Doctor” is usually appended to his name, it is in essence
honorary, since his only formal technical training was as a part-time
engineering student in Vienna.

By the age of 25, the young Ferdinand Porsche had entered the
field of automotive design. His first car design was already
accepted by Lohner & Co. of Vienna. Over the next 20 years,
Ferdinand Porsche, the temperamental but brilliant engineer
succeeded in associating with every major automobile manufacturer
in Germany. At the same time, he designed a dozen of the most
technically significant cars in history.

Working for Mercedes-Benz, he helped develop the most revered
Mercedes-Benz cars of all time: the SSK series. For NSU, he
designed Auto Union Wanderer and the Type 32, a precursor of the
Volkswagen Beetle.

After being dismissed from Mercedes for disagreeing with the firm's
staid engineering policies, Porsche decided to establish what later
became Porsche A.G.: his own engineering consulting group. In a
small office in Stuttgart, the senior Dr. Porsche gathered a select
group of engineers to work under the dramatic name, "Doctor of
Engineering Ferdinand Porsche, Inc., Construction Facility for Land,
Air, and Sea Transportation." One of his employees was his youthful
son, Ferry. His primary interest was one that any young man might
select: sports and racing cars

The senior Dr. Porsche and his team were kept extremely busy. The
consulting firm developed for Steyr (now the utility-vehicle wing of the
Steyr- Daimler-Puch combine), the Austria luxury sedan, but it did not
progress beyond the prototype stage.  They worked a lot for Auto
Union, now Audi: the company developed the Front, the world's first
front-drive economy car. They astonished Auto Union with the mid-engine
Grand Prix cars and their supercharged V-12 and V-16 engines
which, together with Mercedes- Benz racers, dominated European auto
racing for nearly a decade.

After that, the firm created its best-known designs for NSU and Zundapp.
The pair of prototypes was characterized by Dr. Porsche's patented
torsion-bar suspension and a rear-mounted engine. Since neither
company moved rapidly enough to manufacture the designs, Porsche
sold the concept to the German government. Then, he oversaw the
construction of a plant on Wolfsburg to manufacture the design. His
drawings called the car the Type 60. The world came to know it as the
Volkswagen Beetle

After the second World War, the Porsche Company started to create vehicles
that beard its name, and so became knows world wide. Now, nearly a
century later, Porsche became the marque and the family that created
outstanding, often unique and surely lasting contributions to automotive
engineering and design.

Easy Site Prep

Site prep is the best term that is used to describe
the operations necessary to make raw land ready
to accept improvements such as buildings, parking
lots, roads, and other amenities.  Once the project
has been completed, the site prep is invisible.

The term site prep is a broad term that can include
several different tasks, such as clearing and
grubbing, soil erosion, sediment control, storm
drains, water and sewer pipes, topsoil stripping,
rock removal, underground utility, and several
other tasks.

Soil erosion and management
To protect the quality of the water, soil erosion
and sediment control measures are vital.  With
most locations, storm water permitting is
required.  All erosion and sediment control
measures and devices must be in place and inspected
before the first tree drops or first shovel full
of dirt is removed.

The designs for storm water management systems
are becoming more and more complex.  The detension
basins have complex and spiraling side slopes
and bottoms that have almost flat grades.

Clearing
The limits of clearing can be marked with a GPS
dozer.  By following the outline of the display
in the cab, the bulldozer can cut a path through
the wooded area so other equipment will have a
clear line to go by.

The traditional method used to clear debris, such
as burning, is rapidly fading away.  The air
pollution standards will prevent any type of
burning of most areas across the United States.

Site prep made easy
Depending on the job site, what you have to do will
vary greatly.  With excavation, what is needed to
complete a job is as different as night and day.  No
matter what type of work you are doing, it will
almost always require the use of heavy machinery.

Clearing lots for houses, grading roads, laying
pipe, fixing water leaks, and digging foundations
are just some of the most common tasks found with
the art of excavation.  To do this type of work,
it takes a special individual as work is outdoors
year round, meaning that you freeze in the winter
and burn up in the summer.

Laying pipe is a task that takes skill.  You first
must dig the trench for the pipe, making sure that
the elevation is right, and that the pipe will meet
the specifications listed in the blueprints.  There
are several different types of pipe that needs to
be layed, including water, sewer, and storm drains.

When you first begin your job, you'll need to have
the proper permits from the area that you are going
to be disturbing the ground in.  Once you have
the proper permits, you can begin your work.  With
some jobs, you'll need to document on paper just
how much land you disturb each day.

Sometimes with excavation, the job site and plans
will call for ponds or temporary ponds.  This can
be fun to do, although you have to be careful as
well.  Very common with sub divisions, ponds are
something that take a lot of skill to dig right.

Manholes are something else that you will encounter
as well.  You can use machinery to set them in place,
although they will need to go a certain way.  The
easiest way to put them in place is by using an
excavator, as you can lower it down and have a
couple of workers set it in place.

Anytime you are working on an excavation site, you
should always be careful and make sure you do things
by the book.  There are always rules and regulations
that you need to follow.  Excavation is a very fun
trade, although you'll need to be well versed with
following plans, running machinery, and having fun
outdoors.

Dump Truck

Dump trucks or production trucks are those that are
used for transporting loose material such as sand,
dirt, and gravel for construction.  The typical dump
truck is equipped with a hydraulically operated open
box bed hinged at the rear, with the front being
able to be lifted up to allow the contents to fall
out on the ground at the site of delivery.

Dump trucks come in many different configurations
with each one specified to accomplish a specific
task in the construction chain.

Standard dump truck
The standard dump truck is a full truck chassis with
the dump body mounted onto the frame.  The dump body
is raised by a hydraulic ram lift that is mounted
forward of the front bulkhead, normally between the
truck cab and the dump body.

The standard dump truck also has one front axle,
and one or more rear axles which normally has dual
wheels on each side.  The common configurations for
standard dump trucks include the six wheeler and
ten wheeler.

Transfer dump truck
For the amount of noise made when transferring, the
transfer dump truck is easy to recognize.  It's a
standard dump truck that pulls a separate trailer
which can be loaded with sand, asphalt, gravel,
dirt, etc.

The B box or aggregate container on the trailer is
powered by an electric motor and rides on wheels
and rolls off of the trailer and into the main dump
box.  The biggest advantage with this configuration
is to maximize payload capacity without having to
sacrifice the maneuverability of the short and
nimble dump truck standards.

Semi trailer end dump truck
The semi end dump truck is a tractor trailer
combination where the trailer itself contains the
hydraulic hoist.  The average semi end dump truck
has a 3 axle tractor that pulls a 2 axle semi
trailer.  The advantage to having a semi end
dump truck is rapid unloading.

Semi trailer bottom dump truck
A bottom dump truck is a 3 axle tractor that pulls
a 2 axle trailer with a clam shell type dump
gate in the belly of the trailer.  The biggest
advantage of a semi bottom dump truck is the
ability to lay material in a wind row.  This
type of truck is also maneuverable in reverse as
well, unlike the double and triple trailer
configurations.

Double and triple trailer
The double and triple bottom dump trucks consist
of a 2 axle tractor pulling a semi axle semi
trailer and an additional trailer.  These types of
dump trucks allow the driver to lay material in
wind rows without having to leave the cab or stop
the truck.  The biggest disadvantage is the
difficulty in going in reverse.

Side dump trucks
Side dump trucks consist of a 3 axle trailer pulling
a 2 axle semi trailer. It offers hydraulic rams
that tilt the dump body onto the side, which spills
the material to the left or right side of the
trailer.  The biggest advantages with these types
of dump trucks are that they allow rapid unloading
and carry more weight than other dump trucks.

In addition to this, side dump trucks are almost
impossible to tip over while dumping, unlike the
semi end dump trucks which are very prone to being
upset or tipped over.  The length of these trucks
impede maneuverability and limit versatility.

Off road dump trucks
Off road trucks resemble heavy construction equipment
more than they do highway dump trucks.  They are
used strictly for off road mining and heavy dirt
hauling jobs, such as excavation work.  They are
very big in size, and perfect for those time when
you need to dig out roads and need something to
haul the massive amounts of dirt to another
location.

Hydraulic Machinery

Hydraulic machinery are machines and tools that use
fluid power to do the work.  Almost all types of
heavy equipment is a common example.  With this type
of equipment, hydraulic fluid is pumped to a high
pressure then transmitted through the machine to
various actuators.

The hydraulic pumps are powered by engines or electric
motors.  The pressurized fluid is controlled by the
operator with control valves and then distributed
through hoses and tubes.

The increasing popularity of hydraulic machinery is
due to the large amount of power that is transferred
through small tubes and flexible hoses.  The high
power density and wide array of actuators can make
use of this power.

Hydraulic power
The theory that lies behind hydraulic equipment is
fluid pressure.
1.  A force that acts on a small area can
create a bigger force by acting on a larger area
by hydrostatic pressure.
2.  A large amount of energy can be carried
by a small flow of highly pressurized fluid.

Pumps
A hydraulic pump will supply the fluid to the
components in the system. Pressure in the system
will develop in reaction to the load.  Pumps have
a power density of around ten times greater than
an electric motor.  The pumps are powered by an
electric motor or engine, which is connected through
gears, belts, or a flexible elastomeric coupling
to reduce the heavy vibration.

The common types of hydraulic pumps for hydraulic
machinery applications include:
1.  Gear pump - the gear pump is cheap,
durable, and simple.  It is less efficient, simply
because it is constant displacement and suitable
for pressures that are below 3,000 psi.
2.  Vane pump - vane pumps are cheap, simple,
and reliable.  They are good pumps for higher flow
low pressure output.

Hoses and tubes
A hydraulic hose is graded by pressure, temperature,
and compatibility of fluid.  A rubber interior is
surrounded by multiple layers of woven wire and
rubber.  The exterior of the hose is designed for
resistance against abrasion.

The bending radius of the hydraulic hose is
designed very carefully into the machine, since
a hose failure can be deadly, and violating the
minimum bend radius of the hose can also cause
failure.

A hydraulic pipe is thick enough to have threads
cut into it for connections.  It's rarely used
for high pressure systems though, which prefer to
have tubes or hoses.  The pipe itself lends to
weldings and can also be used to fabricate the
manifold.

Hydraulic pipes on the other hand are preferred
over hoses whenever possible, as they are simply
more durable.  Tubes are also preferred over pipes,
as they weigh a lot less.  Hydraulic tubes will
normally have flared ends and captive nuts to
make connections.  They can also be steel welded
with floating nuts and face seal fittings on the
ends.

Both tubes and pipes for hydraulic applications
traditionally haven't been plated or painted,
since the temperature and oil they operate under
drive away moisture and reduce the risk of rust.

Fittings
The fittings with hydraulic machinery serve
several purposes:
1.  To bride different standards, such
as the O-ring boss to JIC or pipe threads to the
face seal.
2.  Allows proper orientation of
components, as a 45 or 90 degree, straight, or
even swivel fitting will be chosen as it is
needed.  They are designed to be positioned in
the correct orientation and then tightened as
needed.
3.  To incorporate bulkhead hardware.
4.  A quick disconnect fitting may be
added to a machine without having to modify hoses
or valves.

Craft Idea for a Group: Make a Mural

Most craft ideas are geared to individuals, whether kids or adults.  Sometimes you'd like to have a craft idea that works for a group of kids working together.  Making a mural together is an idea that works for a group.  By working together, you are creating something to decorate a shared area.  Individual crafts can be displayed, but one unique item is often more effective than a group of items that are almost identical.  In addition, sometimes kids' crafts, like it or not, just become clutter when they are taken home, and it isn't long before Mom throws it out.  This craft idea of making a group mural can be displayed for several weeks and will not become clutter in anyone's home.

The basic materials for a kids' group mural is freezer paper.  Freezer paper is about 18 inches wide, and it is very tough.  One side is plastic coated.  That is the side that is designed to be placed against the food.  You will have better luck drawing on and gluing things onto the other side.  Class or group murals can feature a number of different design elements.  You can mix up some finger paint and let the children make hand prints (or even foot prints!) on the paper.  You can let them scour old cast-off magazines and color catalogs for pictures they like and let them cut the pictures out and glue them on.  They can add scribbles, designs, signatures, slogans, or pictures using markers, crayons, or gel pens.  They can attach stickers to the mural as well.  This craft idea is very flexible!

For making the mural, choose a topic that relates to the group in some way.  If the group are girl scouts, for instance, and have been learning to camp, the mural can feature pictures of items related to camping.  If you've been learning about dinosaurs, you can use them as a theme.  If you want a really messy project that makes a cute mural for fall, mix up finger paint in fall colors.  The children can each make a tree by first laying their forearm in brown paint.  Then they lay their arm on the paper to make the trunk of the tree.  They should spread out their fingers so their arm print has five short branches at the top.  To make the leaves, the children make fingerprints all around the top of the tree using paints in other fall colors.  If you add a few drops of dishwashing detergent to finger paint when mixing it up, it will be easier to clean off the children's arms.  Do make sure they have old clothes or smocks for this craft idea.

Little preschoolers will like making a mural with an animal theme.  You should probably find and cut out animal magazine pictures to start with, and then let the children choose the ones they like for gluing down.  Glue sticks are neat to use with small children.  They will paste some of the pictures upside down.  Expect it and do not scold them.  It is the process that is important in this craft idea.  The children can also use animal cookie cutters dipped in finger paint to stamp animals on the mural, too.  You may need to tape the paper to the table so it doesn't slide around while the children work.

An elaborate form of this craft idea that adults often make is a quilt around a theme.  Each person in the group creates a quilt square to represent some aspect of what the group stands for.  These quilt squares can be colored with fabric pens or crafted of patchwork or applique.  Again, the craft idea is to build group solidarity and not to highlight one artist's skills over another.  When the quilt top is completed, it can be a group project to tie it or quilt it.  It can be hung in a special central location or given to an appreciated leader or member.