Topics in Basic TechnologyDefinitions of technology and their explanations Examples of technology Forms of technology explained with their differences Types of chain drive Types of belt drive Types of Ceramics Advantages and Disadvantages of Chain Drives Len Academy Questions for Basic Technology JSS3, 2nd Term Len Academy Basic Technology Questions, JSS3 Belt and Pulley Drives: Types of belt in belt drives Refrigerator as an electromechanical device, its parts and operations What is chain drive? Classification of chain drive What are Belt Drives? 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 What is Maintenance? Types of Maintenance Hardwood and Softwood - Characteristics and Examples What are Ceramics? Characteristics of Ceramics
Academic Questions in Basic Technology
The _____ functions to remove excess heat from the refrigerator.
D. Expansion Valve
F. Defrost System
A fluid or gas that runs through the compartments of a refrigerator is termed _____.
A. Water vapor
B. Liquid vapor
E. Compressed water
F. Evaporated water
Current flows through a path called _____.
B. Electric Route
E. High Tension
F. Electric Circuit
Googles are safety wears.
Which of the following is false concerning advanced ceramics?
A. They can be made from metallic oxides
B. They are very hard and durable
C. They are corrosion resistant
D. They are fired in the presence of oxygen
E. They are fired at a very high temperature of about 1700oC
F. They can be made from non-oxides such as carbides and borides
A thin continuous line is used for representing the followings except _____.
B. Hatching lines
C. Long breaks
D. Diagonal line used to state plane surfaces
E. Leader lines
F. Back section lines
With regards to chain drives, the diagram above is a/an _____ chain.
A type of chain drive commonly used in bicycles is the _____ chain.
A chain drive is defined as a system comprising an endless chain running over two sprockets, bringing about mechanical movements in the process.
Below are explanations of the various types of chain drive:
The roller chains are very common since they are used in bicycles, motorcycles and vehicle engines.
They are made up of a series of small cylindrical rollers attached together at both sides of its entire length.
The roller chain requires the sprockets in order to transmit mechanical power. Meanwhile, recall that the sprockets refer to toothed wheels over which an endless rotational chain is fitted. Please see the image of the roller chain in the above diagram.
Roller chains can be single-stranded or multiple-stranded.
Also called the inverted tooth chains, the silent chains are series of toothed link plates that are attached to one another in a pin-like manner. This manner of attachment allows for free flexing of the chains.
Silent chains operate with reduced noise levels and can move more loads at higher speed than a roller chain of the same width.
Functionally, silent chains are preferably used in industrial equipment where quietness, silence and smoothness are required.
Meanwhile, always understand that it is quite difficult to connect together the silent chains from different manufacturers.
They are preferable used for lifting processes rather than power transmission. They don’t need meshing with sprocket sockets because they are made to run over sheaves.
Leaf chains are commonly utilized in trucks that lift large and heavy loads.
The flat-top chains are manufactured for the purpose of conveying materials. For this reason, they are widely used in conveyors.
They consist of plates made up of steel with hinge-like barrels curled on each side with pins inserted into the barrels to create joints acting as both beams and bearings.
The connecting pins in a flat-top chain are usually enlarged or knurled at one end, giving rise to its continuous length.
Detachable chains are made up of similar links that can be easily detached from one another. Each of the link comprise of a hook-shaped end in which adjacent articulation occur.
Detachable Chains will usually transmit power at lower speed.
Detachable chains can be easily assembled and disassembled by pulling up the slack and flexing the links, then sliding a link sideways.
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Amazing facts in Basic Technology
Rubber bands last longer when refrigerated
Lighter was invented before matches
Johann Wolfgang Dobereiner was credited with the invention of lighter in 1826 while the match was made 3 years later
Volkswagen group of companies own some of the top cars of the world. These are Audi, Bentley, Bugatti, Ducati, Lamborghini and Porsche
Notable points in Basic Technology
Arrowhead lines are lines with pointed edges at one or both ends. The pointed edges are in the form of an arrow.
Arrowhead lines are used:
At the end of dimensional lines.
As measurement lines.
A thin continuous line could be a straight or curved line. However, the main point to remember is this: 'it is a tiny line with no dot or dashes within it'.
A thin continuous line is used for representing the followings:
Short center lines
Diagonal lines used to state plane surfaces
Backside section lines
Any action that involves the servicing, checking, replacing and repairing of an equipment, object or device is termed maintenance.
Maintenance has two main goals. These are:
To prevent a breakdown
To repair the breakdown
Below are the types of maintenance:
Softwoods are often derived from coniferous trees, that is: trees with needle-like leaves, and whose seeds are covered in cones.
Below are some characteristics of softwood:
Most softwood have lower densities than hardwood (weighs lower).
In terms of price, they are often less expensive than hardwood.
Their growth rate is faster than hardwood.
Most softwood do not shed their needle-like leaves during the year. However, the softwood 'larch' and 'cypress' are exceptions.
They are less fire resistant.
The diagram below shows the various types of line in technical drawing, their description and general application: