1. If you need to use a ladder, you must select the app […]
1. If you need to use a ladder, you must select the appropriate ladder, the ladder is basically divided into two categories, one is straight ladder (straightladder), first, the word ladder (stepladder). Ladders can not stand alone, must be against the fixture, the US Occupational Safety and Health Department regulations ladders to be higher than the top length (Special note 3 feet of the ladder: feet) than 91 centimeters above the level to be reached, commonly referred to as ultra extension, hyperextension main purpose is to make the center of gravity of the fixture close to a straight ladder, the ladder is less likely to tip over when the person up and down. But if the ladders can not meet the requirements of hyperextension, then the top of the ladder shall be fixed and ladders should be equipped with devices or help grab the handrail to provide staff with the ladder at all times to maintain three points of contact at the top and bottom (ie feet and one hand) .
2. There are ladder material metal, wood and glass fiber, what materials to use ladders should we do? While many people know that metal ladder can not be used in places where the risk of electric shock, but there are still many people in the United States due to the bare metal ladder falls down the line and electrocuted each year, but particular attention, even wooden ladder and glass fiber ladder same problem may occur electrocution in wet. Although fiberglass ladder advantageous strength and lightweight, but very easy fiberglass deteriorated due to sun exposure, some of the additional chemicals can easily damage the glass fibers. Thus, when glass fibers are used for a particular inspection ladder and other characteristics such as color change or cracking damage. Ladder there are heavier than aluminum ladder and easy to aged deterioration disadvantages.
3. Select the ladder should pay attention to the maximum load limit, overweight people or carry heavy items up and down the ladder should pay special attention. United States according to a ladder truck into light work (lightduty), work (mediumduty), heavy work (heavyduty) and overweight work (extraheavyduty) four grades, respectively, the maximum load of 91 kg (200 lbs), 102 kg (225 lbs) , 114 kg (250 lbs) and 136 kg (300 lbs). (Currently no such specification) 4, how to distinguish good quality aluminum ladder aluminum ladder aluminum-based alloy general. The main alloying elements are copper, silicon, magnesium, zinc, manganese, minor alloying elements are nickel, iron, titanium, chromium, and lithium. Aluminum ladder low density, but relatively high strength, approaching or exceeding the high quality steel, can be processed into a variety of profiles, with excellent electrical conductivity, thermal conductivity and corrosion resistance, widely used in industry, usage after steel. Aluminum ladder divided into two categories: cast aluminum alloy is used in the cast; wrought aluminum alloy, can withstand pressure processing, mechanical properties than cast. Processed into various forms, specifications of aluminum material. Mainly used in the manufacture of aviation equipment, daily necessities, building doors and windows. Aluminum alloy processing methods can be divided into wrought alloys and cast aluminum. Wrought aluminum alloy is divided into non-heat-strengthened aluminum alloy and heat treatment strengthened type alloy. Enhanced heat treatment can improve the mechanical properties by heat treatment, it can be achieved by cold deformation strengthening, which includes high purity aluminum, industrial high purity, rust-proof aluminum and industrial aluminum. Heat treatable aluminum alloys may be heat treated to improve mechanical properties by means of quenching and aging, it can be divided into hard aluminum, wrought aluminum, super-hard aluminum and special aluminum alloy. Some heat-treated aluminum ladder may be employed to obtain good mechanical properties, physical properties and corrosion resistance. Cast aluminum alloy chemical composition of Al-Si alloy, aluminum-copper alloy, magnesium alloy, aluminum-zinc alloy and aluminum rare earth alloy, wherein the aluminum-silicon alloys and simple aluminum-silicon alloy (heat treatment can enhance the mechanical properties of the lower casting good performance), (special aluminum-silicon alloy can be heat strengthened, high mechanical properties, good casting performance).
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