Note: for the tower crane with trolley luffing, a two-way trolley luffing rope breaking protection device should be set to ensure that the trolley will not move on the boom when the wire rope is broken when the front and rear traction of the trolley; The axle breaking protection device must ensure that the trolley cannot be separated from the boom even if the wheel fails.
For tower cranes running on rails, limit devices shall be set in each running direction, including limit switches, buffers and terminal stops.
Tower crane, i.e.
1、 10.
Multi tower operation 1) special construction scheme shall be formulated and approved for multi tower operation.
2) The vertical distance between the lowest part of the high-level tower crane (or the hook rising to the highest point or the lowest part of the counterweight) and the highest part of the low-level tower crane shall not be less than 2m.
2.
4) The traveling tower crane shall be equipped with traveling stopper, which shall be sensitive and reliable.
Note: the tower crane should be installed with a lifting moment limiter.
5.
10 inspections.
Note: the tower crane without collector in the slewing part should be installed with slewing stopper to prevent cable damage.
The inspection and evaluation of tower crane shall comply with the “10 inspections”.
3) The tower crane with the height of the hinge point at the root of the boom greater than 50m shall be equipped with anemometer, which shall be sensitive and reliable.
2) The minimum erection distance between any two tower cranes shall meet the specification requirements.
The guarantee items shall include: ① load limiting device, ② travel limiting device, ③ protective device, ④ hook, pulley, drum and wire rope, ⑤ multi tower operation, ⑥ installation, disassembly, acceptance and use.
The surface that the device may contact with the wire rope shall not have edges and corners.
2) The tower crane with trolley luffing shall be equipped with trolley travel switch, and the tower crane with boom luffing shall be equipped with boom amplitude limit switch, which shall be sensitive and reliable.
Protective device 1) the tower crane with trolley luffing shall be installed with rope breaking protection and shaft breaking protection devices, which shall meet the specification requirements.
When the slewing limit operates in both positive and negative directions, the rotation angle of the boom shall not be greater than ± 540 °.
The repair, inspection and scrapping of steel wire rope shall comply with the provisions of the current national standard “maintenance, installation, inspection and scrapping of crane steel wire rope” gb/t5972.
The electric shock of the moment limiter controlling the constant amplitude variation or the contact controlling the constant amplitude variation shall be set separately and can be adjusted separately; For tower cranes with trolley luffing, the maximum luffing speed exceeds 40m/min.
The construction of tower crane without lifting shall strictly comply with the operating procedures, and the following “10 no lifting” shall be achieved: 1 Pull objects askew without lifting 2 Don’t lift if the load is overloaded or the weight is unknown 3 Objects buried underground or stuck on the ground with unknown weight shall not be hoisted 4 Do not lift if there is no command or multiple command, illegal command and unclear signal 5 Small objects are not hoisted without basket or beyond the edge of basket 6 Do not lift when there are people standing on the lifting object or moving objects 7 If the binding of lifting objects and accessories does not meet the safety requirements, do not lift 8 Lifting objects with sharp edges and prismatic objects shall not be lifted without protective measures 9 Do not lift if the safety device fails 10 No hoisting in severe weather such as rainstorm, Blizzard, heavy fog, strong wind above level 6.
2) Lifting torque limiter shall be installed and shall be sensitive and reliable.
4.
2) Buffers and stop devices shall be installed at the end of track travel of traveling and trolley luffing, and shall meet the specification requirements.
tower crane, according to the standard for safety inspection of building construction jgj59, the safety inspection and evaluation shall comply with the provisions of the current national standard safety code for tower cranes gb5144 and the current industrial standard safety technical code for installation, use and disassembly of tower cranes in building construction jgj196.
General items should include: ⑦ attachment, ⑧ foundation and track, ⑨ structural facilities, ⑩ electrical safety.
Note: the minimum erection distance between any two tower cranes shall comply with the following provisions: 1) the distance between the boom end of the low tower crane and the tower body of the other tower crane shall not be less than 2m.
2) Pulley and drum shall be equipped with wire rope anti falling device, which shall be complete and reliable, and the wear of pulley and drum shall be within the specified allowable range.
2.
Travel limit device 1) the lifting height limiter shall be installed, and the safe override of the lifting height limiter shall meet the specification requirements, and shall be sensitive and reliable.
When the lifting torque is greater than the rated value under the corresponding working conditions and less than 110% of the rated value, the power supply in the rising and amplitude increasing directions shall be cut off, but the mechanism can move in the falling and amplitude decreasing directions.
Inspection and evaluation of guarantee items in the inspection scoring table of tower crane 1 The load limiting device 1) should be installed with a load limiter that is sensitive and reliable.
Hook, pulley, drum and steel wire rope 1) the hook shall be equipped with a steel wire rope anti decoupling device, which shall be complete and reliable, and the wear and deformation of the hook shall be within the specified allowable range.
The limit switch shall ensure that the minimum distance between its end and the buffer is greater than 1m when the tower crane stops after the switch action.
When the lifting capacity is greater than the rated value of the corresponding gear and less than 110% of the rated value, the power supply in the upward direction should be cut off, but the mechanism can move in the downward direction.
The gap between the surface of the device and the outer edge of pulley or drum side plate shall not exceed 20% of the wire rope.
If the safety distance between two adjacent tower cranes is not properly controlled, it is likely to cause major safety accidents..
Note: the drum of pulley, hoisting and boom luffing tower crane shall be equipped with wire rope anti falling device.
4) When the height of the top of the tower crane is greater than 30m and higher than the surrounding buildings, obstacle indicators should be installed.
3.
3) The tower crane without collector in the rotating part shall be equipped with rotating stopper, which shall be sensitive and reliable.
When the trolley runs outward and the lifting torque reaches 80% of the rated value, the luffing speed shall be automatically converted to no more than 40m / min.
3) The wear, deformation and corrosion of the steel wire rope shall be within the specified allowable range, and the specification, fixation and winding of the steel wire rope shall meet the requirements of the instructions and specifications.
