Common problems and preventive measures of materia

Common problems and preventive measures of building material elevator

material elevator (hereinafter referred to as elevator) is a kind of material vertical transportation machinery commonly used in construction sites. Because it has the characteristics of low manufacturing cost, simple installation and operation, and strong applicability, it is widely used by construction enterprises. Especially for some small and medium-sized construction sites, it plays a decisive role. With the development of the construction market, the number of hoists has also increased, so the contradiction of relatively lagging management of hoists has become more prominent. Many hoists are not manufactured according to the standard requirements, and the construction enterprises themselves do not regulate their installation and use, so that the existing hoists have different degrees of safety problems. In particular, some common safety problems have never been fully understood, and there are endless troubles. Judging from the recent local statistics of safety accidents, the safety accidents on the hoist have an obvious upward trend, which once again sounded an alarm to us. It is urgent to standardize the management of material hoists

to sum up, the material elevator mainly has the following problems

1. In terms of manufacturing

the main reason is that the manufacturer does not produce according to the requirements of standards and specifications. There are two reasons: first, the manufacturer itself does not understand or understand the standards and specifications; Second, in order to reduce costs and cater to the market, manufacturers artificially cancel some safety protection devices

(1) no safe parking device. This is a very important safety device. When the basket reaches the base of the building and needs to unload, the parking device can be put down to make the basket fall on the frame. At this time, the steel wire rope is in a relaxed state to alleviate the fatigue of the steel wire rope and ensure the safety of workers entering the basket for unloading. At present, a large number of hoists in the construction site do not have such devices. Some manufacturers' families do not add such parking devices for the ground, and some equipment operators deliberately remove the devices and are unwilling to use the parking devices during operation. This is an act that does not meet the requirements of the specification (this is very dangerous and should be resolutely corrected, otherwise it will be stopped - editor)

(2) use a single steel wire rope. At present, many hoists still use the method of hanging the basket with a single steel wire rope. The load of the steel wire rope in operation is large, and the accident of the basket falling due to the breakage of the steel wire rope often occurs. Because some specifications require that the basket must be hung with a double steel wire rope. There are two common ways: one is to use the string method of four rope hoist wire rope or the installation method of double drum winch to reduce the stress load of a single wire rope; The second is the method of installing the movable pulley on the basket. The steel wire rope passes through the fixed pulley on the crown beam and then through the movable pulley on the basket, which can reduce the stress load of the steel wire rope by half and effectively prevent the steel wire rope from breaking due to overload

(3) the installation requirements of overhead and low frame hoists are not clearly distinguished. Generally, we refer to hoists over 30m as overhead hoists. Compared with low frame hoists, elevated hoists have higher requirements in installation, but manufacturers often ignore them. For example, the specification requires that the overhead hoist cannot use friction winch as power, the cable windrope can only be used as attachment frame, and the overhead hoist should have lower limit device and buffer device, etc

(4) the basket has no safety door. At present, it is very common for baskets not to install safety doors. Equipment operators can easily remove the safety doors of baskets at will. Safety doors must be provided as required by the specification and the form of interlocking should be adopted

the above four points are deducted according to the JGJ standard (as a manufacturer, producing such inferior products, it should be closed for rectification - editor)

2. Installation

at present, most hoists are installed by construction enterprises themselves. Due to weak technical force, poor personnel quality, and lack of understanding of standards and specifications, there are many problems in the installation, so it is urgent to standardize the management in this regard

(1) the scaffold foundation is unstable. The specification clearly stipulates the specific requirements for the foundation during the installation of high and low frames:

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the foundation of elevated hoists should be designed and calculated; When there are no design requirements for the low frame hoist, G20 concrete with a height of 300mm can be poured after the plain soil is compacted (the bearing capacity is not less than 80kPa). But now many hoists have not done so, and some have not done any foundation. They just stand the frame on the ground, which affects the stability of the frame

(2) the erection of the entrance protective shed is not standard. The main problem is the strength of the protective shed, that is, the impact capacity of falling objects is insufficient, and the area of the protective shed is insufficient. The specification stipulates that the requirements for the erection of the protective shed are 3m in front of and behind the low frame and about 5m in the overhead frame, and the width is slightly larger than the frame width

(3) the erection of unloading platform is not standard. Whether the unloading platform is erected stably or not directly affects the safety of operators, which is also the main reason for derrick falling accidents. Strictly speaking, the unloading platform should be made into a stand-alone platform, that is, the platform can only be erected in the form of standing poles from the ground or building ties, and cannot be connected with the scaffold, so as to avoid affecting the stability of the scaffold

(4) the installation of wall frame and cable wind rope is not standard. The wall frame and cable wind rope are the devices to stably lift the frame body, and the biggest problem is that the installation is not standardized. For example, the interval between the wall attached frames is required to be no more than 9m, and a group of 10~15m wind cables should be set, with 4 cables in each group. In addition, the cable wind rope material requires the use of round strand steel wire rope, with appropriate tension during installation, etc

(5) upper and lower limit stops are not installed. These are the devices to prevent the basket from hitting the top and directly impacting the ground. They are very important safety protection devices, especially the upper limit limiter cannot be omitted

(6) the installation of the landing door is not standard. The specification requires that the parking door is 1.8m high, and a certain distance should be maintained from the frame, and the force instigation device should be used to clearly distinguish the 5N interlocking device

(7) no or incomplete vertical protection. Construction enterprises often do not pay enough attention to this aspect. In fact, this is not only the need of safety protection, but also the need of civilized construction

3. How to use and operate the equipment correctly is very important, that is to say, human factors are the key. Due to the low quality of construction workers and the lack of necessary safety knowledge and safety awareness, Hb 5287 (1) 996 metal axial loading decadent experimental method and insufficient safety training often lead to some safety accidents

(1) insufficient use and maintenance of equipment. Equipment operators do not understand the performance of the equipment and lack maintenance of the equipment, resulting in leakage, abnormal noise and vibration of equipment such as motors, reducers and hoists, which greatly reduces the service life of the equipment and directly affects the civilized construction on site

(2) remove some safety protection devices on the equipment at will. For example, upper and lower limit stops, safety doors, safety parking devices, etc. (this is the most important safety device - editor)

(3) illegal operation. For example, it is unsafe for people to get on and off the elevator, not to use the safe parking device when running, and to put their heads into the frame, which should be resolutely eliminated

although the principle of the material hoist is simple and the structure is not complex, people often tend to ignore its safety. In order to better strengthen the management of material hoists, first of all, every construction enterprise should be familiar with the standards and specifications and purchase equipment that meets the standards and specifications; At the same time, strengthen communication with manufacturers to make them familiar with standards and produce products that meet standards and specifications; On the other hand, we must strengthen the management of equipment installation qualification, so that the installation unit with the corresponding technical level can install; The last is to strengthen the three-level training and education of operators, and improve the technical level and safety awareness of workers operating equipment