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Braking System
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Investigation into safety locking device

There are four main types of brake which is most popular in the market, they are internal brake drum, external brake drum, Caliper disk brake and differential band brake. Different braking system will have different characteristic. Here are some comparison of those system characteristic and conclude the braking system that we should use.

 

band brake:

Comparison of different types of brake:

 

 

operating temperature

Brake factor

Stability

Wet and humid

Differential band brake

Low

Very high

Very low

Unstable but still effective

External drum brake

Low

Moderate

Moderate

Unstable if humid; poor performance if wet

Internal drum brake

Higher than external brake

High

Low

Unstable if humid; completely ineffective if wet

Caliper disk brake

High

Low

High

Good

When we looking at the stability of differential band brake, we find that it is very slow, and it is poor for permanent brake, we don’t consider it. And we don’t wasting time on the study of it.

 

External brake drum

Advantage

Disadvantage

Moderate stability

Low operating temperature

Moderate brake factor

poor performance if wet

Easy to install

 

Cheaper than internal brake drum

 

 

 

By the comparison, external brake drum is not suitable for this project, since it is difficult to install in a simple manner to our machine. If we want to install it, we need to make a thick braking shoe for the machine. The thick shoe will increase the inertia of the system and make the machine much more difficult to stop rotation. In addition, this type of brake doesn’t perform well at high temperature.

 

Internal brake drum

 

Advantage

Disadvantage

Resist high temperature

Low stability

High brake factor

Difficult to install

 

Difficult to manufacture

Can only use hydraulic power

Expansive

For the internal brake drum, we can see that it has high brake factor and resist high temperature. But when we consider its disadvantage, we found that it is difficult to install to our machine, since its shoes are inside the drum. If we need to install it into the machine, we need to design a new device for this braking system. However, due to the limit of time and the cost, we don’t use this braking device. In the other hand, if we designed to use this system, we need to use hydraulic power. But using hydraulic power will increase our cost. Although the performance of internal brake drum is the best, the cost and technology is not suitable in our situation.

 

Caliper disc brake

Advantage

Disadvantage

Resist high temperature

Low brake factor

High stability

 

Easy to install

 

Can use cable instead of hydraulic power

 

Cheap

 

For the caliper disc brake, we can see that there are many advantages. The only disadvantage it has is the low brake factor. However, braking factor is quite important to our system. So we should do more study on it. If the performance of this caliper disc brake is satisfactory, we will use this type of brake.

 

Base on the simple estimation, we think that caliper disc brake is possible to install to our machine. The estimation is that, caliper disc brake is widely use in vehicle, the inertia of a car is larger than a furnace, the rotational of the furnace is very slow (5.99rpm), so caliper disc brake has the ability to stop the furnace. So in the following time, we will focus on the caliper disc brake and do more study on it.

In fact the working principle of bicycle brake is very similar to the Caliper disk brake. On the other hands, the piece of a bicycle brake is very low, so that we can use the bicycle brake as our braking system. To ensure the bicycle brake is usable in the system, here we will have some calculation to verify it

In the market the price of type 2 (~$20) is move lower than the type 1(~$100). In addition, the power transmission of type 2 is also better than type 1. So we will use type 2 as the braking system of our machine.

To ensure the bicycle brake is functional in the system, here will have some calculation to verify the performance of this type of brake. Normal speaking, any type of brakes can stop the moving object, it depend on the force that we apply and the time need to stop the object. So in the following calculation, we will mainly focus on calculation of the force and the time needed to stop the furnace.