Basic Technology

Belt Drives, Types, Advantages and Disadvantages of Belt Drives

len Alfred Ajibola - Fri, 09th August, 2019 @ 14:42

Topics in Basic Technology

Electromechanical Energy: Parts of the Refrigerator and how they operate Chain Drive, Types, Classifications, Advantages and Disadvantages Belt Drives, Types, Advantages and Disadvantages of Belt Drives Type of Lines in Technical Drawings Len Academy questions for Basic Technology, JSS2, 2nd Term Len Academy questions for Basic Technology JSS2, 2nd Term, Part 2 Maintenance, Types of Maintenance Hardwood and Softwood - Characteristics and Examples Ceramics, Types and Characteristics of Ceramics

Academic Questions in Basic Technology

Please check out our Test Your Knowledge page to see all Questions and Answers

Which of the following is not a function of thin continuous line in Technical drawing?

  • A. Used for representing projection lines
  • B. Used as construction lines
  • C. Used for representing visible outline and edges
  • D. Used for representing leader lines
  • E. Used as intersection lines
  • F. Used as measurement lines

The following are Types of Line in Technical Drawing EXCEPT _____.

  • A. thin continuous line
  • B. inverse head line
  • C. thin dash line
  • D. continuous thin straight zigzag line
  • E. free hand line
  • F. chain thin line with thick ends

What are Belt Drives?

Belt drives are one of the drive meachnisms or transmissions employed in machines to bring about mechanical movement via power transmission.

It is important to understand that the most ideal and simplest form of transmitting mechanical power is via the rotational motion; and the belt drive proves to be very useful here.

Please read on the Concept of Motion here.

As an instance, a pepper grinder uses a drive (in the form of a belt) to propel forward its shaft.

Similarly, a sewing machine utilizes a belt (as its drive); and it can be mechanically moved via the "foot actions" of the tailor.

The image below shows a belt drive connecting two pulley systems:

Belt Drive - Len Academy

From the diagram, we can see that the belt drive requires a belt as its mechanism for mechanical power transmission.

Apart from belt drives, Other methods of mechanical power transmission includes:

  • Chain Drives
  • Gear Drives

Please read on Chain Drive, its Advantages and Disadvantages here.

In the drive system, the machines are driven by rotational motion through its shaft to the other parts around it.

The driving pulley of the machine is termed the Driver System while that which is driven is termed the Driven System.

Note: A pulley is a wheel or sets of wheel over which a belt or chain is attached in order to create a movement or motion.


Belt and Pulley Drives

The belt drives are frictional drives that transmit mechanical energy on a dry surface from one shaft to another in a pulley-like system.

For the belt drive to work properly, both sides of the shaft must be dry and separated (by some distance).

Note: Either shafts or pulleys do not necessarily need to rotate at the same speed; neither must they be of the same size.

The tension between both sides of the belt will depend heavily on the angle of contact such that the tight side is always below while the slack end stays above. (Please see the above diagram).

The area of belt having a lesser tension (less tightly stretched) is generally referred to as the slack side while that having a higher tension (more tightly stretched) is the tight side.

Think of tension as the level of tightness at which something is stretched.

Note: In belt drives, mechanical power is usually transmitted from the driving pulley to the driven pulley via a rotational motion.

Based on the fact that belt drives are used in conjunction with pulleys; some of the mechanisms that utilize belt drives include:

  • Pepper Grinder
  • Sewing Machines
  • Industrial Generators
  • Motor Cars and so on

Types of Belt in Belt Drives

The belts used in machines utilizing the belt drive system can be of the following types:

Belt Types in Belt Drive - Len Academy

  1. Flat Belts: These belts are somewhat rectangular in shape; and they bring about rotational movement over long distances; and with a very low noise. The flat belts have a very high efficiency of about 98%.
  2. Vee Belts: They are used with grooved pulleys and can allow for high speed and rotation. They are relatively common because of their low cost and numerous size ranges.
  3. Circular Belts: These belts are circular in shape. They can also be used with the grooved pulleys.
  4. Cylindrical Belts: These belts are looped and flat. They are often used in milling machines.

Note: Materials used in making the various kinds of belt drives include rubber, plastic, fabric, leather and other synthetic materials.


Types of Belt Drives in Pulley Systems

Below are the various type of belt drives that are often used alongside a pulley system:

  • Open Belt Drive

Open Belt Drive - Len Academy

The open belt drive is used when two parallel shaft are needed to rotate in the same direction.

When the open belt drive is in used on a widely separated shaft, the upper side of the belt must be the slack side while the lower side becomes the tight side.

Please read on Lines here.

Note: If we made the upper side the slack side (in a separated shaft), sagging will occur and the contact arc will be increased.


  • Cross Belt Drive

Cross Belt Drive - Len Academy

The cross belt drive is used when two parallel shaft are needed to rotate in the opposite direction.

Due to the crossing nature of this belt, the belts rub against itself at a specific junction, resulting to its wearing off and eventual damage.

Note: In order to reduce the excessive wear caused from the meeting point of the crossed belts, the shafts should be placed at an optimum distance from each other; while been operated at low speeds.


  • Fast and Loose Pulley Drive

Fast and Loose Pulley Drive - Len Academy

A fast and loose pulley drive is often used when the driven pulley is required to be started or stopped without creating an interference with the driving pulley.

Note: The pulley keyed to the machine shaft is referred to as the fast pulley.

  • The fast pulley runs at the same speed with that of the machine shaft.
  • The loose pulley on the other hand runs freely over the machine shaft without transmitting any power.

You can Attempt Len Academy Examination Questions for JSS2, 2nd Term here.


Advantages of Belt Drives

  1. They are economical.
  2. They are great shock absorbers.
  3. They don’t usually generate noise.
    Please read on Pollution and Waste Management System here.
  4. They have a high efficiency rate (up to 98% efficiency rate).
  5. They are excellent in transmitting power between widely spaced shafts.
  6. The shafts do not need to be parallel to one another.
  7. They show you visual signs when they begin to fail.
  8. They don’t requiring oiling or lubrication.


Disadvantages of Belt Drives

  1. They deteriorate when exposed to chemicals.
    Please read on Acids, their Physical and Chemical Properties here.
  2. They effectively operate only at a temperature of about -35oC – 38oC.
  3. Once damaged, they can’t be repaired.
  4. They build up heat.
  5. Belt drives can occupy larger space in the machine.
  6. The slipping of belt occurs; thus disrupting speed.

THANKS FOR READING - Please Help Share!


Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.

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