1.4. Types of Scrapers

So, now let us discuss about the types of the scraper. So, there are different types of scrapers. So, in this we have classified based on whether the scraper needs assistance from the other machines during its loading operation or not based upon that we have done this classification. Pusher loaded means that scraper needs the assistance of a pusher or a tractor or a bulldozer during its loading operation, those scrapers are called as pusher loaded scrapers. So, there are certain scrapers which are self loading in nature. That means it does not need the assistance of other machines during its loading operation. That is why they are called as self loading. So, we can classify the pusher loader into single power axle and tandem power axle, we are going to discuss that in the upcoming slides. Similarly, self loading also there are different types, push-pull and elevating.

Scrapers are essential machines used in construction for moving earth. They can be classified based on their loading capabilities. Pusher loaded scrapers require a secondary machine, like a bulldozer, to assist during the loading phase; it helps to push the scraper to fill its bowl with dirt. In contrast, self-loading scrapers can fill their bowls without needing additional machines. These two classifications help determine which scraper is best suited for a specific job, considering the requirements of assistance needed for the loading operation.

Think of a pusher loaded scraper as a person who needs a friend to help them lift a heavy box. This friend (the bulldozer) provides the extra strength needed to make the job easier. On the other hand, a self-loading scraper is like someone who can lift the box by themselves without any help. Both can get the job done, but the second person can do it independently.

So, now first let us see what are pusher loaded scrapers? So, I have shown the schematic sketch earlier, this is your scraper machine which is leading. The trailing one is your bulldozer. So, hope you remember what type of blade you will fix for assisting other machines. So, you are using a cushion blade, C blade, C blade is attached to the bulldozer just for pushing or assisting the other machines. So, you know that the scrapers are tyre mounted, normally wheel mounted machines. So, for the wheel mounted machines, the tractive effort generated will be lesser when compared to the crawler or track mounted machines. So, the coefficient of traction will be poor. So, the amount of tractive effort generated will be less for the wheel mounted machines, to supplement the loading power of this wheel mounted scraper you can take the help of a crawler mounted or track mounted bulldozer.

Pusher loaded scrapers are designed to work together with bulldozers or similar machines. In this arrangement, while the scraper is collecting dirt, the bulldozer pushes it to make the loading process faster and more efficient. Since scrapers are usually wheeled vehicles, they might not generate enough traction to load heavy materials efficiently without assistance. A bulldozer, with its track design, provides the necessary support to optimize the loading process, thereby increasing productivity.

Imagine trying to move a heavy sack of potatoes by yourself versus having a friend help you. When you each push together, it’s much easier to lift and move the sack. Here, the scraper is you, and the bulldozer is your friend providing that extra push to make the task quicker and easier!

So, now let us see what are these are single versus tandem powered axle scrapers? So, axle basically how do you classify the axle into powered axle and dead axle? See in our common vehicle say for example car, so you know that it may not be the case like all the axles are powered. So, maybe we only one axle may be powered the other axle we just dead ok powered in the sense the powered axle will transfer the power to the wheel those wheels are called driving wheels. So, the other axle will be just dead axle which would not transfer the power to the wheel, it will just act like a steering component. So, the axle which serves to transmit the power to the wheel is called a powered axle, the axle that carries a wheel without power to drive it, it is called as it dead axle, they are just acting like a suspension steering component.

Scrapers can also be classified by the type of axle configuration they have. In single powered axle scrapers, only one axle provides the power to move the scraper. This is sufficient for standard working conditions. However, in challenging terrains where greater traction and power are needed, tandem powered axles (where all axles are powered) are preferable. This arrangement enables the scraper to traverse difficult surfaces efficiently, reducing slippage and improving overall performance.

Imagine riding a bicycle with only one powered wheel—it can go straight on smooth pavement but has trouble on dirt roads. Now think of a four-wheel drive car where all wheels are powered, making it easier to go over rocks or mud. Tandem powered axle scrapers are like that four-wheel drive, giving extra grip and strength for tougher jobs.

So, next is your self-loading scraper. So far, we have discussed about the pusher loaded scraper where it needs the assistance of a pusher during its loading operation. In the scrapers it is self loading, that means it can load on its own, it does not need the assistance of another machine during its loading operation. So, but basically these machines are heavier and costlier when compared to a conventional pusher loaded scrapers that is one limitation of this machine. So, under the self loading, there are different types.

Self-loading scrapers are advanced machines that do not require any external help to fill their bowl with materials. This autonomy allows them to operate independently, which can be useful in projects where space is limited or when waiting for additional equipment is impractical. However, due to their complex design and added components, they tend to be more expensive and heavier than their pusher loaded counterparts, which could be a consideration for project budgeting.

Think of a self-loading scraper like a standalone robot vacuum cleaner. It can navigate your home, clean the floors, and avoid obstacles on its own without needing a helper. It may cost more than a regular vacuum cleaner, but its ability to operate independently saves you time and effort.

The another type of to self loading scrapers is your push pull scrapers. Here, these machines are not going to take the help of other machine like a pusher. But let us say for example, the scrapers which are employed in a project site. So, they will do a teamwork. Teamwork in the sense if there are 2 scrapers, one is in the leading position, the other one is in the trailing position. See, the one which is in the leading position. So, it will pull the trailing for the scraper when the trailing scraper is doing the loading operation.

Push-pull scrapers are designed to increase efficiency by working in pairs rather than needing a bulldozer for assistance. In this setup, one scraper leads and does the hauling, while the other follows behind and assists in loading. By working together, they maximize productivity and can complete tasks faster than operating individually. This creates a system where each scraper helps the other without relying on an additional machine.

Think of push-pull scrapers like a pair of skaters in a synchronized routine. One skater leads the move, while the other follows closely behind, making the performance seamless. They don’t need a third partner (like a bulldozer) to look good, and together they can perform tricks and moves much more smoothly than if they were alone.

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