Views:71 Author:Site Editor Publish Time: 2019-09-24 Origin:Site
With the evolution of nature, human beings have gradually embarked on a different evolutionary path from other animals. In order to survive in harsh natural environment and escape the attack of many ferocious animals, climbing became the need of survival and safety of early human beings. As a result, early humans used climbing trees and natural slopes as auxiliary conditions for climbing. Human ancestors were inspired by natural conditions, and the rudiments of ladders came into being.
According to the views of scholars in various countries, the generation of ladders or stairs is inspired by the above two aspects, forming the trunk method and the slope method. The former is a step ladder, the latter is a step. With the development of human civilization, ladders and steps have become essential functional conditions in buildings with floors.
As a tool, small ladder appeared in ancient times. The original meaning of stepped word-making is a strip-shaped multi-level wooden instrument which is easy to climb. It is not difficult to see from the writing and interpretation of ancient Chinese characters that this is a tool for human climbing. In modern times, it gradually evolved into many different forms and uses. There are outdoor, indoor, fixed, mobile, civil, engineering, military, commercial and so on. With the development of human civilization and material prosperity, ladders have already entered thousands of households.
A ladder is a tool for climbing height by force. Ladders are daily necessities. The tool is edged by two long and thick rods, which cross the cross bar suitable for climbing, and is used for climbing. The ladder is divided into lifting single ladder and lifting herringbone ladder.
Ladders can be divided into many types in terms of material, style and use.
From the material: aluminum alloy, stainless steel, FRP, iron, bamboo, wood and so on.
From the style: straight ladder, herringbone ladder, telescopic ladder,dual-purpose ladder, one-sided ladder, double-sided ladder, multi-functional ladder, car wash table, shelf ladder, foldable step ladder and so on.
From the insulation: non-insulation, semi-insulation, full insulation.
From the use: home ladder, engineering ladder, folding step ladder, dual-purpose ladder, car wash lader, shelf ladder.
When we use ladders, here are some things we should pay attention to.
1. Ladders should be placed on solid and smooth ground. Do not place on ice, snow or skiing surfaces without ski-proof and Fixtures
2. Ladders are forbidden in case of physical fatigue, taking drugs, drinking or physical handicap.
3. Do not stand on the ladder within 1 meter from the top of the ladder when working. Always maintain a 1-meter safety protection height, not to mention climbing the top of the highest support point
4. It is forbidden to exceed the maximum load-bearing quality marked in operation.
5. Use of ladders in strong winds is prohibited
6. Metal ladder conducts electricity, avoiding being close to the place with electric field.
7. When climbing, people face the ladder with their hands firmly grasped and their body center of gravity maintained in the center of the two ladder pillars.
8. Do not exceed the top of your head when doing homework, lest your body lose its balance and become dangerous.
9. It is forbidden to cross directly from one side of the ladder to the other.