L68A1 Mast Section Find out what the difference is between the two tower hangers.
A small car variable amplitude tower crane amplitude limiter
For the tower crane with variable amplitude of the horizontal arm frame, the amplitude limiter is used to remove the one-way working power supply of the variable amplitude mechanism to ensure the safe operation of the car. The principle is the same as the lifting height limiter, which is generally installed on the side of the roller side of the car amplitude converter mechanism.
The amplitude limiter includes a cam set, a breaker and a deceleration device. When the amplitude converter works, the length of the released rope can be known according to the number of rotating rings of the drum recorded. The coil drives the deceleration device. The deceleration device causes several cam groups to rotate. These cams act on the micro-switch, thus cutting off the corresponding amplitude. Control loop, At this point, the variable size car can only run in the opposite direction.
Two-action arm tower range limiter
For the ARM-type tower crane, the amplitude limit switch of the lower and higher arm frame should be set, and the device to prevent the arm frame from rebounding and turning. A amplitude display shall also be installed to enable the operator to keep abreast of changes in amplitude and to prevent significant damage from falling over the frame.
The amplitude indicator of the movable arm crane has two functions: indicating the pitch variation of the working range of the moving arm and preventing the arm frame from turning back and forth. It is installed at the intersection of the right front arm root of the top of the tower.
The amplitude indicator and limiting device consists of a half circular movable turntable, brush support, seat plate, dial rod, and limit switch. The dial rod rotates with the arm frame pitch. The electric brush is connected to the contact point of the indicator light according to different angles. The different elevation angles of the lifting arms are transmitted to the amplitude indicator disk of the upper and lower driver's cab through the light extinguishing signal. When the angle between the lifting arm and the horizontal angle is less than the limit angle, the brush is connected to the buzzer to send a warning signal, indicating that this is not the normal operating range and no lifting operation is allowed. When the arm frame elevation angle reaches the limit angle, the upper limit switch action, the amplitude change circuit is cut off the power supply, thus playing a protective role. From the knowledge of the light signal on the amplitude indicator plate, the tower crane driver knows the elevation angle of the lifting arm frame and the operating range and maximum allowable lifting weight at this time.
When the boom is close to the maximum elevation angle and the minimum elevation angle, the baffle in the splint pushes the lever drive of the limited-position switch installed at the intersection of the arm roots, thus cutting off the power supply of the variable-amplitude mechanism and stopping the variable-amplitude action of the boom. The action of the limiter can be adjusted by changing the length of the block.
