9 Safety protection device
9.1 General
Safety protection devices are necessary measures to prevent accidents of lifting machinery. Including devices that limit the movement stroke and working position, devices that prevent cranes from overloading, devices that prevent cranes from tipping and slipping, interlocking protection devices, etc. This chapter lists typical crane safety protection devices. See Appendix A for the setting requirements of crane safety devices. The safety protection devices of other types of cranes are shown in each sub-standard.
9.2 Safety device to limit movement stroke and working position
9.2.1 Lifting height limiter
The lifting mechanism shall be equipped with lifting height limiter. The lifting mechanism that is driven by an internal combustion engine and is directly mechanically connected without electric, hydraulic, pneumatic and other transmission links can be equipped with light or sound alarm devices to replace limit switches.
When the retrieval device rises to the upper limit position specified in the design, it should be able to immediately cut off the lifting power source. Above this limit position, there should be enough vacant height to meet the requirements of rising braking stroke. Under special circumstances, such as lifting molten metal, a second-level lifting height limiter should be installed to prevent overtravel and topping, and the second-level lifting height limiter should disconnect the higher-level power source.
When necessary, a descent depth limiter should also be set; when the retrieval device descends to the lower limit position specified in the design, it should be able to immediately cut off the descent power source.
After the power supply of the above movement direction is cut off, the movement in the opposite direction can still be carried out (except the second-stage lifting height limiter).
9.2.2 Running stroke limiter
Cranes and hoisting trolleys (except suspension electric hoist running trolleys) should be equipped with a travel limiter in each direction of travel, and automatically cut off the power source in the forward direction when the limit position specified by the design is reached. When the running speed is greater than 100m/min, or the parking positioning requirements are strict, a two-stage running stroke limiter should be installed as needed. The first stage sends a deceleration signal and decelerates as required, and the second stage should be able to automatically cut off. Electricity and parking.
If the crane and the lifting trolley often reach the limit position of operation during normal operation, the maximum deceleration of the cab should not exceed 2.5m/s2.
9.2.3 Amplitude limiter
9.2.3.1 "For power-driven boom luffing cranes (except for hydraulic luffing), amplitude limiters for the low and high positions of the boom shall be set at the extreme positions of the boom pitching stroke.
9.2.3.2 For tower cranes that use mobile trolley luffing, an amplitude limit device shall be installed to prevent the movable lifting trolley from quickly reaching its maximum or minimum amplitude. The crane with the maximum luffing speed exceeding 40m/min, when the trolley runs outwards and when the lifting torque reaches 80% of the rated value, it should be automatically converted to a low-speed operation lower than 40m/min.
9.2.4 "Amplitude indicator
Lifting machinery with luffing mechanism should be equipped with an amplitude indicator (or boom elevation indicator).
9.2.5 Device to prevent the boom from tipping backwards
Cranes with boom luffing mechanism (except hydraulic cylinder luffing) should be equipped with a device to prevent the boom from tilting backwards (for example, a mechanical stop rod with buffer) to ensure that the travel switch of the luffing mechanism fails It can prevent the boom from tipping backward.
9.2.6 Rotation limit
When it is necessary to limit the rotation range, the rotation mechanism should be equipped with a rotation angle limiter.
9.2.7 Rotary locking device
When necessary, the slewing part of mobile cranes and other slewing cranes should be equipped with a slewing locking device.
9.2.8 outrigger retraction locking device
For mobile hoisting machinery that uses vertical outriggers to support operations during work, the vertical outriggers should be extended and positioned by the hydraulic system; and the outrigger retraction locking device should be installed so that the outriggers can be reliably locked after being retracted .
9.2.9 Anti-collision device
When two or more cranes or cranes are running on the same track, anti-collision devices should be installed. In any case of a collision, the deceleration in the cab should not exceed 5m/s2.
9.2.10 Buffer and end stop
The operating mechanism of the crane running on the track, the operating mechanism of the hoisting trolley, and the luffing mechanism of the crane should all be equipped with buffers or buffer devices. The buffer or buffer device can be installed on the crane or the rail end stop device.
The stop device at the end of the track should be firm and reliable to prevent the crane from derailing.
For the luffing drive mechanism with screw and rack, the end of the luffing rack and the luffing screw should also be equipped with an end stop anti-drop device to prevent the boom from falling at a low position.
9.2.11 skew indicator or limiter
Gantry cranes and loading bridges with a span greater than 40m should be equipped with deflection indicators or limiters. When the outriggers on both sides run out of sync and deflection occurs, the deflection can be indicated to the driver. When the designed value is reached, the deflection should be adjusted and corrected.
9.2.12 Level
Cranes that use outrigger support or crawler support should be equipped with a level to check the tilt of the crane base.
9.3 Anti-overload safety device
9.3.1 Lifting weight limiter
For power-driven hoisting appliances of 1t and above without the risk of overturning, a lifting weight limiter shall be installed. Lifting appliances that have the risk of overturning and whose rated lifting capacity does not change within a certain range of changes should also be equipped with lifting weight limiters.
When necessary, when the actual lifting capacity exceeds 95% of the rated lifting capacity, the lifting weight limiter should send out an alarm signal (except for the mechanical type).
When the actual lifting capacity is between 100% and 110% of the rated lifting capacity, the lifting weight limiter is effective. At this time, the lifting power source should be automatically cut off, but the mechanism should be allowed to move down.
If the hoisting and/or unbalanced luffing mechanism driven by the internal combustion engine is directly connected to the machine without electric, hydraulic or pneumatic transmission links, the hoisting machine can be equipped with a light or sound alarm device to replace the lifting weight limiter.
9.3.2 Lifting torque limiter
The crane whose rated lifting capacity changes with the working range shall be equipped with a lifting torque limiter.
When the actual lifting capacity exceeds 95% of the rated value of the lifting capacity corresponding to the actual range, the lifting torque limiter should send an alarm signal.
When the actual lifting capacity is greater than the rated value corresponding to the actual range but less than 110% of the rated value, the lifting torque limiter will work. At this time, the unsafe direction should be automatically cut off (ascending, amplitude increase, boom extension or these Combination of actions), but should allow the mechanism to move in a safe direction.
If the hoisting and/or balance luffing mechanism driven by the internal combustion engine is directly connected to the machine without electric, hydraulic or pneumatic transmission links, the hoisting machinery can be equipped with a light or sound alarm device to replace the lifting torque limiter.
9.3.3 Limit torque limiter
For the slewing mechanism with self-locking effect, a limit torque limiting device shall be provided. It is ensured that when the rotation movement is hindered, the slip of the torque limiter can protect the overload.
9.4 Anti-wind, anti-skid and anti-tip device
9.4.1 Anti-wind and anti-skid device
9.4.2 The outdoor rail-mounted cranes shall be equipped with reliable wind and anti-skid devices, and they should meet the specified wind and anti-skid requirements in working and non-working conditions.
9.4.3 The anti-wind braking device under working condition can adopt brake, wheel brake, rail clamp, top rail, rail clamp, rail pin, etc. The brake and release action should be considered to be interlocked with the operating mechanism And should be able to operate automatically from the control room.
9.4.4 If the crane is only equipped with a wind-resistant braking device without an anchoring device, the wind-resistant braking device shall be able to withstand the wind load of the crane in the non-working state; when the wind-resistant braking device in the working state cannot meet the requirements of non-working When the wind resistance and anti-skid requirements are required under the condition, the anchoring device of cable type, bolt type or other forms should also be installed. When the crane has an anchoring device, the anchoring device should be able to independently bear the wind load of the crane in the non-working state.
9.4.5 Anti-wind and anti-skid design in non-working state, if only use brakes, wheel brakes, rail clamps, top rails, rail presses, rail pinning devices and other wind resistant braking devices, its braking and releasing action Should also consider interlocking with the operating mechanism, and should be able to operate automatically from the control room (except for manual control of wind protection devices).
9.4.6 "The anchoring device shall ensure the safety and reliability of the crane and its related parts under the following conditions:
a) When the crane enters the non-working state and anchors;
b) The crane is in working condition, and the crane performs normal operation and implements the anchor timing;
c) When the crane is in working condition and in normal operation, it suddenly encounters a wind load exceeding the limit wind speed of the working condition and implements the anchoring time.
9.4.7 Anti-tip safety hook
Single-beam cranes with hoisting hooks installed on one side of the main beam, cranes with seismic requirements, and other cranes with similar requirements to prevent the lifting trolley from tipping over, should be equipped with anti-tipping safety hooks.
9.5 Interlock protection
9.5.1 The doors to enter the bridge crane and gantry crane, and the hatch door from the driver’s cab to the bridge shall be able to be interlocked and protected; when the door is opened, it shall be disconnected due to the actions of the mechanism that may cause danger to personnel The power of the agency.
9.5.2 When the driver’s cab and the access passage move relative to each other, the passageway into the driver’s cab should be protected by interlocking; when the door of the passageway is opened, the power supply of the mechanism that may cause danger to personnel due to mechanism action should be disconnected. .
9.5.3 The crane that can be operated in two or more places shall be provided with interlock protection to ensure that it can only be operated at one place and prevent two or more places from being able to operate at the same time.
9.5.4 When it can be driven either electrically or manually, the mutual operation conversion shall be interlocked.
9.5.5 Braking devices such as rail clamps and anchoring devices should be able to interlock with the operating mechanism.
9.5.6 For a crane with a trolley running on a tiltable cantilever, the cantilever tilting mechanism and the trolley operating mechanism should be interlocked, so that the trolley can only operate after the tilting cantilever is leveled.
9.6 Other safety protection devices
9.6.1 Anemometer and wind speed alarm
9.6.1.1 For tall cranes operating outdoors, an anemometer should be installed, and the anemometer should be placed on the windward part of the crane.
9.6.1.2 "For tall cranes operating outdoors, a wind speed alarm that displays instantaneous wind speed shall be installed, and an alarm signal shall be issued when the wind force is greater than the set value of the calculated wind speed in the working state.
9.6.2 track cleaner
When materials are likely to accumulate on the track and become obstacles to operation, cranes and lifting trolleys traveling on the track should be installed under the trolley frame (or end beam) and under the trolley frame to sweep the track. The gap between the bottom surface of the board and the top surface of the track is generally 5 mm ~ 10mm.
9.6.3 Anti-car fall protection
The luffing trolleys of tower cranes and other trolleys that require anti-falling cranes should be equipped with a device that prevents the trolley from derailing during operation. Even if the axle is broken, the trolley cannot fall.
9.6.4 Overhaul the cage or platform
Cranes that need to frequently perform self-maintenance of lifting machinery at high altitudes should be equipped with safe and reliable maintenance cages or platforms.
9.6.5 Safety protection of conductive sliding contact line
9.6.5.1 The bridge crane driver’s cab is located on the side of the trolley trolley line. In the section where there is a risk of electric shock, a protective plate should be installed between the ladder and walking platform leading to the crane and the trolley line for isolation.
9.6.5.2 The protective device shall be provided on the side of the trolley line of the trolley of the bridge crane to prevent accidental contact with the trolley line due to the swing of the spreader or the wire rope when the trolley is at the extreme end position.
9.6.5.3 When the multi-storey bridge crane is arranged, the lower crane should be powered by cables or safety trolley lines.
9.6.5.4 For other lifting appliances that use trolley wires, protective devices shall be provided for parts prone to electric shock.
9.6.6 Alarm device
When necessary, operation alarm devices such as buzzers and flashing lights should be installed on the crane. When the mobile crane is running backwards, it should emit a clear alarm sound accompanied by a light flashing signal.
9.6.7 Protective cover
During normal work or maintenance, in order to prevent foreign objects from entering or to prevent parts that may be dangerous to personnel from their operation, protection devices should be provided. The moving parts exposed on the crane that may hurt people, such as open gears, couplings, transmission shafts, sprockets, chains, transmission belts, pulleys, etc., should be equipped with protective covers/bars.
Rainproof measures should be taken for electrical equipment on cranes working in the open air.
9.1 General
Safety protection devices are necessary measures to prevent accidents of lifting machinery. Including devices that limit the movement stroke and working position, devices that prevent cranes from overloading, devices that prevent cranes from tipping and slipping, interlocking protection devices, etc. This chapter lists typical crane safety protection devices. See Appendix A for the setting requirements of crane safety devices. The safety protection devices of other types of cranes are shown in each sub-standard.
9.2 Safety device to limit movement stroke and working position
9.2.1 Lifting height limiter
The lifting mechanism shall be equipped with lifting height limiter. The lifting mechanism that is driven by an internal combustion engine and is directly mechanically connected without electric, hydraulic, pneumatic and other transmission links can be equipped with light or sound alarm devices to replace limit switches.
When the retrieval device rises to the upper limit position specified in the design, it should be able to immediately cut off the lifting power source. Above this limit position, there should be enough vacant height to meet the requirements of rising braking stroke. Under special circumstances, such as lifting molten metal, a second-level lifting height limiter should be installed to prevent overtravel and topping, and the second-level lifting height limiter should disconnect the higher-level power source.
When necessary, a descent depth limiter should also be set; when the retrieval device descends to the lower limit position specified in the design, it should be able to immediately cut off the descent power source.
After the power supply of the above movement direction is cut off, the movement in the opposite direction can still be carried out (except the second-stage lifting height limiter).
9.2.2 Running stroke limiter
Cranes and hoisting trolleys (except suspension electric hoist running trolleys) should be equipped with a travel limiter in each direction of travel, and automatically cut off the power source in the forward direction when the limit position specified by the design is reached. When the running speed is greater than 100m/min, or the parking positioning requirements are strict, a two-stage running stroke limiter should be installed as needed. The first stage sends a deceleration signal and decelerates as required, and the second stage should be able to automatically cut off. Electricity and parking.
If the crane and the lifting trolley often reach the limit position of operation during normal operation, the maximum deceleration of the cab should not exceed 2.5m/s2.
9.2.3 Amplitude limiter
9.2.3.1 "For power-driven boom luffing cranes (except for hydraulic luffing), amplitude limiters for the low and high positions of the boom shall be set at the extreme positions of the boom pitching stroke.
9.2.3.2 For tower cranes that use mobile trolley luffing, an amplitude limit device shall be installed to prevent the movable lifting trolley from quickly reaching its maximum or minimum amplitude. The crane with the maximum luffing speed exceeding 40m/min, when the trolley runs outwards and when the lifting torque reaches 80% of the rated value, it should be automatically converted to a low-speed operation lower than 40m/min.
9.2.4 "Amplitude indicator
Lifting machinery with luffing mechanism should be equipped with an amplitude indicator (or boom elevation indicator).
9.2.5 Device to prevent the boom from tipping backwards
Cranes with boom luffing mechanism (except hydraulic cylinder luffing) should be equipped with a device to prevent the boom from tilting backwards (for example, a mechanical stop rod with buffer) to ensure that the travel switch of the luffing mechanism fails It can prevent the boom from tipping backward.
9.2.6 Rotation limit
When it is necessary to limit the rotation range, the rotation mechanism should be equipped with a rotation angle limiter.
9.2.7 Rotary locking device
When necessary, the slewing part of mobile cranes and other slewing cranes should be equipped with a slewing locking device.
9.2.8 outrigger retraction locking device
For mobile hoisting machinery that uses vertical outriggers to support operations during work, the vertical outriggers should be extended and positioned by the hydraulic system; and the outrigger retraction locking device should be installed so that the outriggers can be reliably locked after being retracted .
9.2.9 Anti-collision device
When two or more cranes or cranes are running on the same track, anti-collision devices should be installed. In any case of a collision, the deceleration in the cab should not exceed 5m/s2.
9.2.10 Buffer and end stop
The operating mechanism of the crane running on the track, the operating mechanism of the hoisting trolley, and the luffing mechanism of the crane should all be equipped with buffers or buffer devices. The buffer or buffer device can be installed on the crane or the rail end stop device.
The stop device at the end of the track should be firm and reliable to prevent the crane from derailing.
For the luffing drive mechanism with screw and rack, the end of the luffing rack and the luffing screw should also be equipped with an end stop anti-drop device to prevent the boom from falling at a low position.
9.2.11 skew indicator or limiter
Gantry cranes and loading bridges with a span greater than 40m should be equipped with deflection indicators or limiters. When the outriggers on both sides run out of sync and deflection occurs, the deflection can be indicated to the driver. When the designed value is reached, the deflection should be adjusted and corrected.
9.2.12 Level
Cranes that use outrigger support or crawler support should be equipped with a level to check the tilt of the crane base.
9.3 Anti-overload safety device
9.3.1 Lifting weight limiter
For power-driven hoisting appliances of 1t and above without the risk of overturning, a lifting weight limiter shall be installed. Lifting appliances that have the risk of overturning and whose rated lifting capacity does not change within a certain range of changes should also be equipped with lifting weight limiters.
When necessary, when the actual lifting capacity exceeds 95% of the rated lifting capacity, the lifting weight limiter should send out an alarm signal (except for the mechanical type).
When the actual lifting capacity is between 100% and 110% of the rated lifting capacity, the lifting weight limiter is effective. At this time, the lifting power source should be automatically cut off, but the mechanism should be allowed to move down.
If the hoisting and/or unbalanced luffing mechanism driven by the internal combustion engine is directly connected to the machine without electric, hydraulic or pneumatic transmission links, the hoisting machine can be equipped with a light or sound alarm device to replace the lifting weight limiter.
9.3.2 Lifting torque limiter
The crane whose rated lifting capacity changes with the working range shall be equipped with a lifting torque limiter.
When the actual lifting capacity exceeds 95% of the rated value of the lifting capacity corresponding to the actual range, the lifting torque limiter should send an alarm signal.
When the actual lifting capacity is greater than the rated value corresponding to the actual range but less than 110% of the rated value, the lifting torque limiter will work. At this time, the unsafe direction should be automatically cut off (ascending, amplitude increase, boom extension or these Combination of actions), but should allow the mechanism to move in a safe direction.
If the hoisting and/or balance luffing mechanism driven by the internal combustion engine is directly connected to the machine without electric, hydraulic or pneumatic transmission links, the hoisting machinery can be equipped with a light or sound alarm device to replace the lifting torque limiter.
9.3.3 Limit torque limiter
For the slewing mechanism with self-locking effect, a limit torque limiting device shall be provided. It is ensured that when the rotation movement is hindered, the slip of the torque limiter can protect the overload.
9.4 Anti-wind, anti-skid and anti-tip device
9.4.1 Anti-wind and anti-skid device
9.4.2 The outdoor rail-mounted cranes shall be equipped with reliable wind and anti-skid devices, and they should meet the specified wind and anti-skid requirements in working and non-working conditions.
9.4.3 The anti-wind braking device under working condition can adopt brake, wheel brake, rail clamp, top rail, rail clamp, rail pin, etc. The brake and release action should be considered to be interlocked with the operating mechanism And should be able to operate automatically from the control room.
9.4.4 If the crane is only equipped with a wind-resistant braking device without an anchoring device, the wind-resistant braking device shall be able to withstand the wind load of the crane in the non-working state; when the wind-resistant braking device in the working state cannot meet the requirements of non-working When the wind resistance and anti-skid requirements are required under the condition, the anchoring device of cable type, bolt type or other forms should also be installed. When the crane has an anchoring device, the anchoring device should be able to independently bear the wind load of the crane in the non-working state.
9.4.5 Anti-wind and anti-skid design in non-working state, if only use brakes, wheel brakes, rail clamps, top rails, rail presses, rail pinning devices and other wind resistant braking devices, its braking and releasing action Should also consider interlocking with the operating mechanism, and should be able to operate automatically from the control room (except for manual control of wind protection devices).
9.4.6 "The anchoring device shall ensure the safety and reliability of the crane and its related parts under the following conditions:
a) When the crane enters the non-working state and anchors;
b) The crane is in working condition, and the crane performs normal operation and implements the anchor timing;
c) When the crane is in working condition and in normal operation, it suddenly encounters a wind load exceeding the limit wind speed of the working condition and implements the anchoring time.
9.4.7 Anti-tip safety hook
Single-beam cranes with hoisting hooks installed on one side of the main beam, cranes with seismic requirements, and other cranes with similar requirements to prevent the lifting trolley from tipping over, should be equipped with anti-tipping safety hooks.
9.5 Interlock protection
9.5.1 The doors to enter the bridge crane and gantry crane, and the hatch door from the driver’s cab to the bridge shall be able to be interlocked and protected; when the door is opened, it shall be disconnected due to the actions of the mechanism that may cause danger to personnel The power of the agency.
9.5.2 When the driver’s cab and the access passage move relative to each other, the passageway into the driver’s cab should be protected by interlocking; when the door of the passageway is opened, the power supply of the mechanism that may cause danger to personnel due to mechanism action should be disconnected. .
9.5.3 The crane that can be operated in two or more places shall be provided with interlock protection to ensure that it can only be operated at one place and prevent two or more places from being able to operate at the same time.
9.5.4 When it can be driven either electrically or manually, the mutual operation conversion shall be interlocked.
9.5.5 Braking devices such as rail clamps and anchoring devices should be able to interlock with the operating mechanism.
9.5.6 For a crane with a trolley running on a tiltable cantilever, the cantilever tilting mechanism and the trolley operating mechanism should be interlocked, so that the trolley can only operate after the tilting cantilever is leveled.
9.6 Other safety protection devices
9.6.1 Anemometer and wind speed alarm
9.6.1.1 For tall cranes operating outdoors, an anemometer should be installed, and the anemometer should be placed on the windward part of the crane.
9.6.1.2 "For tall cranes operating outdoors, a wind speed alarm that displays instantaneous wind speed shall be installed, and an alarm signal shall be issued when the wind force is greater than the set value of the calculated wind speed in the working state.
9.6.2 track cleaner
When materials are likely to accumulate on the track and become obstacles to operation, cranes and lifting trolleys traveling on the track should be installed under the trolley frame (or end beam) and under the trolley frame to sweep the track. The gap between the bottom surface of the board and the top surface of the track is generally 5 mm ~ 10mm.
9.6.3 Anti-car fall protection
The luffing trolleys of tower cranes and other trolleys that require anti-falling cranes should be equipped with a device that prevents the trolley from derailing during operation. Even if the axle is broken, the trolley cannot fall.
9.6.4 Overhaul the cage or platform
Cranes that need to frequently perform self-maintenance of lifting machinery at high altitudes should be equipped with safe and reliable maintenance cages or platforms.
9.6.5 Safety protection of conductive sliding contact line
9.6.5.1 The bridge crane driver’s cab is located on the side of the trolley trolley line. In the section where there is a risk of electric shock, a protective plate should be installed between the ladder and walking platform leading to the crane and the trolley line for isolation.
9.6.5.2 The protective device shall be provided on the side of the trolley line of the trolley of the bridge crane to prevent accidental contact with the trolley line due to the swing of the spreader or the wire rope when the trolley is at the extreme end position.
9.6.5.3 When the multi-storey bridge crane is arranged, the lower crane should be powered by cables or safety trolley lines.
9.6.5.4 For other lifting appliances that use trolley wires, protective devices shall be provided for parts prone to electric shock.
9.6.6 Alarm device
When necessary, operation alarm devices such as buzzers and flashing lights should be installed on the crane. When the mobile crane is running backwards, it should emit a clear alarm sound accompanied by a light flashing signal.
9.6.7 Protective cover
During normal work or maintenance, in order to prevent foreign objects from entering or to prevent parts that may be dangerous to personnel from their operation, protection devices should be provided. The moving parts exposed on the crane that may hurt people, such as open gears, couplings, transmission shafts, sprockets, chains, transmission belts, pulleys, etc., should be equipped with protective covers/bars.
Rainproof measures should be taken for electrical equipment on cranes working in the open air.
