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    Principle and application of automatic rail clamping device for gantry crane

    Source: Release time: 2019/7/25 10:40:39

    Portal crane Principle and application of automatic rail clamping device

     Portal crane

    The structure and working principle of rail clamp
        The rail clamping device and the locomotive are connected through the holes on the rear end of the clamping shaft. When the locomotive is walking, the drag wheel can move along the snake track when the rail is driven by the weight of the rail clamp, and the guide rail is driven by the guide wheel bracket and the guide shaft to float along the track along the fixed axis. It is always controlled in the design value, and the rail clamp can not be rubbed against the track, so that the clamping force of the two jaw jaws is consistent.
    A hook head is designed at the lower end of the jaw iron. The hook can fasten the rail after clamping the rail to clamp the tight rail, which prevents the clamp rail from moving up unexpectedly along its slide way and releasing the clamping force.
    1. mechanical clamp rail clamp
    (1) the technical parameters of each clamp are clamping force 20t; the jaw opening degree is 20 degrees; the opening clamp time is 7S; the clamp time is 10s; the clamp clamp is lowest at the lowest distance from the rail surface 30mm; the windbreak grade is 12.
        (2) design features: clamping mechanism of rail clamping device is locking design. After clamping, the C point is lower than AB connection (Fig. 1), so that clamping force is not affected by other factors, and is kept within design value. Second, the accumulator spring is arranged in the compressible accumulator connecting rod, and the connecting rod can shorten with the compression of the spring, which meets the technical requirements of the over dead point design, and has the compensation function. Production management network. (3) a door crane is equipped with four pairs of rail clamping devices, with a total clamping force of 80t, which can withstand 12 strong gale. At the same time, the design of the clamp hook can prevent the car from turning over. 4. After clamping the rail clamp, the 100mm can be lifted up, so that the distance between the bottom rail and the rail surface can be kept 30mm. When the locomotive is walking, the clamp and the track will not interfere. The centerline of the rail is kept in the design value with the center line of the track, the height of the jaw and the rail surface.
    2. hydraulic mechanism
    (1) technical parameters: hydraulic pump station motor power 5. 5kW; speed 1440r/min; rated pressure 15MPa; working pressure 10~12MPa; rated flow 25L/min; oil storage 40L; oil type H46 antiwear hydraulic oil.
    (2) YV1 gets electricity. When YV3 is out of power, the system is in a high pressure state. The pressure oil is replaced by a reversing valve, a left position, a hydraulic lock, an oil cylinder upper chamber, a piston rod, and a clamp. When YV2 and YV3 get electricity, the system is low voltage. The pressure oil is replaced by the right direction of the reversing valve, the hydraulic lock, the cylinder cavity, the piston rod and the clamp, and the lifting clamp is lifted up to maintain the l00mm of the clamp rail. Such as overload relief valve action. The hydraulic lock function is to seal the oil cylinder, prevent leakage of the oil pipe outside the hydraulic lock and the oil cylinder system, prevent the oil cylinder from returning to the pump due to the stopping of the pump, especially the drop of the clamp after the clamp.
    3. PLC control system
    (1) characteristics of control system
    Each action of the rail clamping device is automatically controlled by the program logic, which lightens the impact of the cart running mechanism when it starts, and has automatic fault detection function and display.
    According to the technical requirements of trolley operation control, PLC has 11 input signals and 9 output signals, with a total of 20 points. The whole PLC control system has 120 steps, and there is no need to communicate with the host computer. Therefore, the SM - 24R type of Sino foreign joint venture Huaguang Electronics Co., Ltd. is chosen.
    (2) PLC control flow
    (1) power on PLC (including power supply after returning power failure, motor protection operation, power supply to work), self checking clamp clamp switch. If there is no clamp in place signal, PLC will activate the alarm light and hydraulic station, automatically complete the clamp action, and the clamp signal will keep the clamp position.
    2. The cart goes to the traffic, and the direction of the traffic lights, the delay action, the action of the hydraulic station, the time delay, the opening of the clamp (electromagnetic valve), the opening of the rail clamping device, the PLC receiving the signal of the clamping forceps, the braking action of a large vehicle, the time delay, the start of the cart motor, and the cart's walking.
    3. Stop the cart without any traffic instructions (the cart has been moved), stop the car motor, delay the action of the clamp action, PLC receive the clamp in place signal, stop the hydraulic station and the alarm light, zero signal return linkage table.
    4. The limit action of the cart travel is carried out according to the stopping action procedure. The master control switch is invalid when the operation is in the same direction, and the reverse operation is carried out according to the driving action.
    The operation of the cart should start from zero position.
    4. system workflow
        When the automatic control rail clamping device loosens, the handle of the walking switch is loosened. After receiving the walking instruction, the automatic control center starts the oath device first, then starts the hydraulic pump, and opens the solenoid valve. The oil output by the hydraulic pump goes through the reversing valve to the lower cavity of the oil cylinder, the piston shrinks, the hinge shaft drives the connecting rod to move on the slide way of the support, and then the clamp rail is pulled by the connecting rod pin to pull the clamp into the inside and guide the clamp shaft. When the iron rail is completely disconnected from the rails, the two hydraulic clamps will be raised to the top stop point, the top stop point switch will be closed, the electromagnetic relief valve will be opened, and the information that can be moved will be fed back to the automatic control center. After receiving the information, the automatic control center first loosens the walking brake, then starts the walking motor, and drives the running mechanism to make the locomotive on the track. Mobile.
        When walking is stopped, the handle of the walking switch is pulled back to the middle position. After the automatic control center receives the termination of the walking instruction, it first cuts off the power of the walking motor and causes the locomotive to enter the free sliding state. When the slide is basically completed, the walking brake is automatically tightened, then the hydraulic oil pump is started, the electromagnetic reversing valve is opened, the high pressure oil enters the upper cavity of the human oil cylinder, and the piston extends outwards. The movable hinge shaft moves downward in the support slide way, and the clamp rail clamp falls on the two sides of the top stop point of the clamping rail clamp rail along its clamping rail surface along its clamping rail surface, and opens the upper part of the clamping rail clamp arm through the connecting rod to rotate outward, and at the same time rotates around the clamp shaft, so that the lower end of the clamping rail is closed to the inside, and the jaw iron is tightly attached to the rails above the A and B connection; at this time, the piston of the hydraulic cylinder continues to extend outwards. When the clamp rail is limited by the clamp shaft and the support of the rail, the lower end can no longer be closed to the inside. Therefore, when the pressure of the hydraulic cylinder presses the connecting rod, the rod will compress the spring inside it, so that the length of A, C two points, B and C two points will be shortened, and it will be in A. The spring is compressed at about 10mm above the B connection. The hook head of the clamp rail fastens the rail, and the clamping force at this time has met the technical requirements. Then, under the thrust of the hydraulic cylinder, the middle hinge shaft is pushed to the lower stop point, so that the C point is lower than the A and B wires for mechanical self locking, so that the clamping force is not released. At the same time, it automatically cuts off the power of the walking mechanism.