Foundation Technical requirements before installation of jib crane track beam

• The strength grade of the concrete leveling layer of the jib crane is C30, and the thickness is 30～50 mm.
• The concrete leveling layer should be checked before construction according to the requirements of the track beam installation deviation, if it does not meet the requirements, then the track beam should be adjusted.
• According to the measured elevation of the track beam surface, determine a suitable control elevation of the top surface of the concrete leveling layer, and set a reference point for controlling the elevation every 214～310 m on the track beam.
• Measured by instrument, the cantilever crane adjusts the elevation of the reference point, sets out the leveling layer of the top surface elevation of the baseline, and then installs the template, clears the top surface of the track beam, and bolt holes in the debris, and bolt holes in the upper mouth blocking, sprinkle water wetting can be poured after concrete.
• The leveling layer top surface must be leveled and compacted, there shall be no stone exposed and uneven phenomenon, and do not allow the use of cement mortar on the surface or another leveling method.
• Cantilever crane construction should be measured and checked at any time with the instrument, the top surface of the leveling layer must meet the following requirements: the bolt at the 400 mm width range of the top surface of the unevenness ≤ 5 mm; any 610 m length of the bolt at the top surface of the elevation difference ± 3 mm; along the whole length of the bolt at the top surface of the elevation difference ± 5 m.
• Cantilever crane concrete using mechanical mixing, construction should be strengthened maintenance, when the concrete test block reaches 75% of the strength of the design value, before the track installation work.

Jib crane transmission and brake modification method

Crane transmission is a key component of the construction machinery car, through the jib crane transmission changes the transmission ratio, and the engine crankshaft rejection, to adapt to the starting, acceleration, driving, and overcoming a variety of road obstacles, such as different driving conditions on the drive wheel traction and speed of the different requirements of the need. Construction machinery operating conditions, the operating environment is very complex, and variable, strong mobility, the engine load changes in the work process, and frequent changes in the speed of mechanical operation, to ensure that the construction machinery can achieve high efficiency and energy-saving operations, rapid mobility, the need to constantly adjust the mechanical gear.

The braking device is an important part of ensuring the safe and normal work of the crane. In the lifting operation, the braking device is used to prevent the suspension is the item or boom fall, prevent the turntable or crane in the wind or ramp force under the action of sliding, or make the running mechanism reduce the speed, stop the movement; jib crane can also be according to the need to work to hold the heavy running; special circumstances, through the control of the balance of power and gravity, to adjust the speed of the movement.

When making the joint sleeve and sub-transmission high-grade gear ring engagement, the crane planetary gear shaft, output shaft, planetary gear inner gear ring, and the sub-transmission input shaft gear are fixed together and synchronous rotation, then the sub-transmission into high-grade (direct gear), the main transmission of the five gear ratio that is, respectively, equal to the combination of transmission five smaller ratios. As there are two transmission ratio values are very close, so save a transmission ratio, composed of 9-speed transmission.

Jib crane braking device is divided into brake and stop two kinds. The stopper can only make the shaft free rotation in one direction, and can not absorb kinetic energy, only to support the items stationary. Crane working mechanism in general should be equipped with a brake, only in the following cases, you can not install the brake:

1. The mechanism is driven by the cylinder for linear motion, locking oil circuit can be relied on to stop the mechanism.

2. The manual operation of the bridge crane mechanism, and is not subject to the wind or ramp force.

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