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BAB 6: LOADERS & BAB 6: LOADERS & HAULERSHAULERS
LOADERSLOADERS Definition: is a type of tractor, that uses
a wide bucket on the end of movable arms to lift and move material.
also called a front end loader or bucket loader.
The assembly may be a removable attachment or permanently mounted.
LOADERS Often the bucket can be replaced
with other devices. Large loaders, usually have only a
front bucket and are called front loaders.
Small loader tractors are often also equipped with a small backhoe and are called backhoe loaders.
LOADERS Used mainly for:
uploading materials into trucks, transport building materials- over short
distances. clearing rubble, and digging.
Not most efficient Cannot dig very deep except backhoe
Front end loaders mounted on rubber tires or tracks
and is one of the most versatile equipment.
can be equipped to operate as a loader, a dozer, a scraper, a forklift, a backhoe or a crane.
Mounted on large rubber tires. three manually gear - permits good mobility
when traveling from one jobsite to another.
large rubber tires - good traction on unstable surfaces and allow to perform on side slopes of 15 % and on front slopes up to 30%.
hydraulic system - control of the front-end loader attachments and steering system.
Rubber-tired front end loader
Rubber-tired front end loader
Mounted on crawler tracks. has a lower speed- decreases its mobility;
however, can be operated on side slopes of up to 35% and on front slopes of up to 60%.
hydraulic system - control of the front-end loader.
crawler tracks- normally semi-grouser shoes that permit it to work on firm ground with little damage to the surface.
Crawler-mounted front end loader
Crawler-mounted front-end loader.
contribute to the efficient performance of front-end loaders.
attached with a bucket, forklift, and backhoe attachments.
allow the front-end loader to be an ideal piece of equipment for construction projects, saving the need for numerous pieces of equipment.
Attachments
Front-end loader attachments
Buckets Two types buckets: a general-purpose bucket
and a multi-segment/ multipurpose bucket. Both types may be equipped on crawler or
rubber-tired wheeled loaders. “general-purpose bucket”- single-piece
bucket constructed of heavy-duty, all-welded steel.
Also attached - replaceable teeth that allows the bucket to be used for excavation of medium-to-hard materials.
“multipurpose bucket”- constructed of heavy-duty, all welded steel
has replaceable teeth attached-for excavation of medium-to-hard materials.
has a two- piece construction that makes it more versatile- can be used as a dozer or a scraper.
Two types of front-end loader buckets
General-purpose bucket. Multipurpose bucket
Loader Operation can dig excavations-such as building
foundations (if the material to be excavated is not too hard.)
Belowground operations require construction of a ramp into the excavation to bring the material out.
slope of the ramp- depends on the type of loader operated; for example, a crawler-mounted loader may dig a more abrupt approach to the excavation.
Ramp construction for belowground excavation
load the dump truck downwind to prevent dirt and dust from blowing back into your face.
Keep the truck close to the work area to minimize loader travel, and keep the work area clean and level.
The bucket is loaded by moving the loader forward with the bucket at the desired digging level and with the engine at full-governed speed.
As the bucket penetrates the material, raise the bucket slightly.
Bucket-loading technique
When transporting material, raise the lift arm to give the bucket the ground clearance.
Keep the travel speed reasonable for safe operation.
Upon reaching the truck, raise the bucket high enough to clear the truck body. Reduce forward speed and dump the load in the center of the dump bed.
Shake the bucket to loosen dirt from within. After the load is dumped, back away, lower the
bucket to the carrying position, and return to the digging area.
Loading the dump truck
HAULERS
used to move materials. known as dump trucks can carry in excess of 300 tons. the size that a hauler could attain
was limited by practical considerations such as efficiency, maneuverability and safety.
Dump trucks A typical dump truck is equipped
with a dump body which is mounted directly on the truck chassis.
Dump bodies range in structural strength and size.
Dump truck operations Dump truck operations During dumping operations, the
truck should be on level ground or inclined uphill with the front of the truck facing downward.
When the truck is in position, release the lower latches of the tailgate with the hand lever.
Then engage the control for the dump truck body.
Hydraulic pressure will begin to hoist the dump truck body, and as the body rises, the load will slide backward under the open tailgate.
If the load piles up and blocks the tailgate, place the truck in low gear and move it forward until there is more space to dump the remainder of the load.
If the load does not slide out easily, have someone dislodge it with a long-handled shovel, taking care not to stand in the immediate dumping area.
When dumping a load of rocks or other large solids, see that the tailgate is latched at the bottom, but unfastened at the top, so that the tailgate can drop down and the load can drop.
Not all dump trucks have tailgate wings. On those that do not, you have to drop the tailgate down and support it with chains.
To spread a load over a large area, shift the truck into low gear and drive it slowly forward while dumping.
The dump truck body can be held in any position by returning the control lever to the HOLD position.
When dumping is completed, lower the body by returning the control lever to the LOWERING position.
Then close the tailgate latches. The load in a dump truck should be
distributed evenly. Some states and countries require
that all loose materials hauled in dump trucks must be covered to prevent spillage on roadways and breaking of vehicle windshields.
