Interlock device for protective door of the inflam

The interlock device of the protective door of the well frame inlet and discharge port is a vertical transportation machine often used in construction sites. It has the economic benefits of converting from impregnation molding to extrusion blow molding. It has simple structure, convenient installation, strong practicability, and is currently applying for a patent. The cost is low. However, due to the limitation of the installation position and operation position of the construction site, poor vision and inadequate protection of the inlet and discharge ports, there are many industrial accidents causing institutional injury. According to table 3.1.9 No. 5 (assurance items) of the standard for safety inspection of building construction (JGJ59-99), 2 points will be deducted for each place where the floor unloading platform has no protective door or does not work, and 4 points will be deducted for places that do not form stereotyped and instrumented. We have trial produced the electrical interlock device of the protective door at the inlet and discharge of the well frame, which has been installed and used on many well frames in our unit, and there has never been a mechanical injury accident. It has the advantages of simple structure, low cost, finalization and instrumentalization, and can be reused by compiling construction technical guidelines

I. working principle

40mm protective door is used for the inlet and outlet of the well frame × 25mm square tube and δ= The 0.3mm steel plate is welded into a protective door with a height of 1500mm (the width is determined according to the model of the well frame), which is installed on the vertical rod of the well frame through the support. A travel switch (see Figure 1) is installed on the door base in the direction of opening the protective door. After the protective door is closed and fixed with a handle, the travel switch is closed, and the main AC contactor of the winch is controlled to pull in. Then the winch can carry out forward and reverse operations, and control the lifting rail to work up and down. Once the protective door is opened and the travel switch is reset, the circuit controlled by the main AC contactor will be cut off (see Figure 2). Release the main AC contactor, cut off the power supply, stop the winch and stop the basket. At the same time, the other group of control contacts of the travel switch are connected to the floor indicator light on the console, and the winch operator knows through the floor indicator light that the protective door of the third floor is not closed, so he can eliminate hidden dangers through intercom in time, so as to effectively carry out safety protection

Figure 1 installation diagram of safety device of protective door

Figure 2 electrical schematic diagram of safety device of well frame unloading platform

II. Protective purpose

a) prevent any part of human body from entering the well frame and causing injury when running up and down the basket. The height of the protective door is 1.5m, the installation height is 1.8m, the space below is 0.3m, and the protective height is 1.8m. When the protective door is closed, the head, hands, feet and any part of the body of the construction personnel shall not enter the well frame. It can also realize various functions by computer, conduct data processing and analysis, and print experimental results

b) the personnel using the derrick must leave the derrick and close the protective door before the basket can run up and down. It prevents mechanical injury and high-altitude falling accidents caused by starting the winch when someone enters and exits the basket due to unclear visual angle and unclear command signal

III. safety technical measures

a) the console complies with the standard for safety inspection of building construction (JGJ59-99), implements "one machine, one switch, one leakage, one box", and is installed with voltmeter, key switch (electric lock SA), emergency stop switch. When the operator leaves the console, take away the key, and then cut off the power supply to prevent the operator from starting the machine without authorization. In case of emergency, pressing the emergency stop switch can also cut off the power supply and stop the machine

b) the interlocking control power supply of the protective door adopts 36V safety voltage, which conforms to the technical code for safety of temporary electricity in construction (JGJ46-88)

c) the compression handle can be freely retracted and rotated. Pull out the pressing handle, turn away from the direction of the protective door, and the protective door opens. When closing the door, pull out the pressing handle, turn to the direction of the protective door, and automatically press the protective door through the spring, so as to effectively prevent the sudden loosening of the protective door, cutting off the power supply and the emergency stop of the basket in the process of getting up and down

d) in the control circuit, the travel switches of the basket super high limit and low limit are connected in series. The overhead can also be connected with the overweight limiter in series to protect the basket super high and overweight

IV. economy

the cost of a console is about 1500 yuan, and the cost of a set of protective doors (including installation support, door seat, travel switch) is about 150 yuan. The one-time investment is not much, which can be reused for more than five years, and the demolition cost is low. (Lu Fangda, Zeng Zhaolin)