INTRODUCTION 1.1
A ladder is a set of steps with a pole on each side. The steps on which a climber’s feet rest on are called rungs and the pole on each side is known as side rail. When the ladder leans on a wall for use, the rungs are seen to be horizontally arranged, each being parallel to the other. The side rails which are usually two (for non self supporting ladders), are placed, one on each of the sides.
The side rails are usually long depending on the height the ladder is originally designed to reach. The distance between the two side rails is dependent on the length of the rungs which are usually less than two feet.
Ladders are made of different materials, different shapes and sizes. There are ladders made of wood, some are made of rope, aluminum and fiberglass. Most self supporting ladders are triangular in shape while the non-self supporting ones take the shape of rectangles. Some ladders are adjustable- this makes it possible for their height to be increased or decreased to reach a required elevation.
Fortunately, an adjustable ladder forms the basis of this project report. One major reason behind the choice of this component is the difficulties encountered by workers whose jobs are done at elevated points. The adjustable ladder has the tendency of reaching higher elevations and enables the worker to work more effectively. If a painter is to paint a two storey building, a ladder with a fixed length cannot be employed considering the fact that no such ladder will attain that height and at the same time give the painter the freedom of reaching every intricate part of the building to be painted.
The electrical poles we know are very high when situated along the road sides, for an electrician to fix cables on them during electrifications, he does not have to stretch his legs in order to reach the apex of the poles. To avoid electrocution, he needs a ladder with a reasonable height to carry out a hitch -free job.
Another reason that triggered the project was the economic benefits of local fabrication. Technology can be transferred and improved on to satisfy the needs of the society where it has been transferred to. The cost of purchasing a foreign made ladder has hampered easy access to having one. Now that ladders can be manufactured using our local materials and in our local workshops, the price will drastically reduce and this will also boost our economy. Local fabrication will go a long way in combating the problem of unemployment if its products are bought and used by our people. Excess importation has also hindered the growth of our economy, so if local manufacturers should be patronized, our country will be better and more self reliable instead of depending totally on imported goods.
LITERATURE BACKGROUND OF THE LADDER. 1.2
Ladders are ancient tools and technology. A ladder was depicted in spider cave in Valencia Spain on a Mesolithic rock painting which is about 10,000years ago. Ladders were also mentioned in the bible which is today referred to as Jacob’s ladder. It was recorded that Jacob had a dream where he saw a ladder reaching from heaven to earth.
It was also shown that the Mesolithic rock painting depicted two naked humans carrying baskets, were employing a long wobbly ladder, which appeared to be made of some kind of grasses to reach a wild honeybee nest to harvest the honey in there.
From the above indication, it is agreeable that the first ladders used by humans were made of strong grasses which could be called woods in form of rope.
In 1862, John H. Basely of Dayton invented the step ladder. When he made it, he put hinges on it which made it foldable when not in use. Some old ladders were made of rope and are still used in some countries. During the Second World War, wooden ladders were made and used due to their strength.
As time passed, people saw the need for using ladders either at homes or industries. This increase in the usage of ladders, no doubt increases the demand for ladders. The increase in demand has also made it possible for ladders to be seen in different shapes, sizes and made of different materials to suit or meet users’ demand.
The shape, size and materials of the ladder, determine the prices of it. The height the ladder is to reach and the environment where it will be used have a lot of say in its choice.