Lifting Machinery Safety Points
1. Steel wire
(1) The amount of wear and corrosion on the surface of the steel wire should not exceed 40% of the original diameter (the wire rope for lifting blazing metal or dangerous goods, the scrap standard for broken wires is 1/2 of that of a general crane).
(2) The wire rope should be free from severe deformation such as kinks, dead angles, hard bends, plastic deformation, and hemp core prolapse, and the lubrication condition should be good.
(3) The length of the wire rope must ensure that the wire rope remaining on the drum is not less than 3 turns when the hook is lowered to the lowest position (including the pit).
(4) There should be more than 2 fixed pressure plates at the end of the wire rope.
(1) The pulley rotates flexibly, is clean and smooth without cracks, and there is no defect in the wheel rim or damage to the wire rope.
(2) When the uneven wear of the wheel groove reaches 3mm, or the wall thickness wear reaches 20% of the original wall thickness, or the diameter reduction of the bottom of the wheel groove reaches 50% of the wire rope diameter, the pulley should be scrapped.
(3) The pulley guard should be installed firmly without damage or obvious deformation.
(1) The surface should be smooth and clean, without defects such as cracks and sharp angles. Defects on the hook do not agree to repair welding.
(2) The hook should rotate flexibly, and the positioning bolts and cotter pins must be fastened intact.
(3) The dangerous section of the lower part of the hook and the undercut section of the threaded part of the hook tail are strictly prohibited from cracking.
(4) The wear amount of the dangerous section should not exceed 10% of the original size, the wear amount of the plate hook bush should not exceed 50% of the original size, and the wear amount of the mandrel should not exceed 5% of the original size.
4. Brake wheel
(1) The action is flexible and reliable, and the adjustment should be moderately tight, without cracks, and the spring has no plastic deformation and no edge.
(2) When the brake wheel is released, the gap between the brake shoe and the brake wheel should be basically equal. The maximum opening of the brake band (one side) should be ≤ 1mm, and the lift should be ≤ 0.7mm.
(3) The braking friction surface of the brake wheel must not have defects that hinder the braking performance, and must not be stained with oil or paint.
(4) The unevenness of the wheel surface should be 1.5mm, the wear amount of the rim thickness of the brake wheel of the lifting luffing mechanism should be less than 40% of the original thickness, and the wear thickness of the rim of the brake wheel of other mechanisms should be less than 50% of the original thickness
(5) For cranes that lift blazing metals, flammable and explosive dangerous goods, or cranes that may cause major danger or loss after the hook slipping, the lifting mechanism should be equipped with two sets of brakes.
5. Limiters and anti-collision devices
(1) The crane should be equipped with limit position limiters for rising and falling. The hoist limiter should ensure that the power supply can be automatically cut off when the hook rises to the limit position.
(2) The operating mechanism should be equipped with a travel limiter and an anti-collision device.
(3) When the cage (car) of the elevator (or elevator) crosses the upper and lower end stations by 30~100mm, the overtravel switch should cut off the control circuit; when it crosses the end station floor by 130~250mm, the limit switch should cut off the main power and Cannot reset automatically. Knife switches are not allowed for limit switches.
(4) Luffing type cranes should be installed with maximum and minimum limit devices to prevent the boom from tilting forward and backward. When the amplitude reaches the maximum or minimum limit, the root of the boom should touch the limit switch to cut off the power supply.
(5) Door cabin interlock protection devices shall be installed outside the cab door of the bridge crane, on the hatch leading to the bridge frame, and on the end beam doors on both sides of the crane; the landing door of the elevator (or elevator) must be equipped with a mechanical and electrical interlock device. The door should be equipped with an electrical interlock device; the safety cabin door on the top of the manned elevator car must be equipped with an interlock protection device; the manned elevator car door should be equipped with a sensitive safety touch panel.
(6) All kinds of limit switches and interlocking electrical parts of hoisting machinery for open-air operations should have anti-rain and snow measures
(1) All kinds of switches have excellent contact, reliable action, and convenient operation, and can quickly cut off the power supply of the electric hand in an emergency (the button box of the electric hoist operated on the ground should also be equipped with an emergency stop switch).
(2) Buffers should be installed in the travel mechanism of large cranes and trolleys, and at the limit position of the stroke bottom of the side lifts at the four ends of the rail terminal columns.
(3) All kinds of buffers should be installed firmly. Adopt rubber buffer, the thickness of the trolley is 50~60mm, and the thickness of a big car is 100~200mm.
(4) The track end stop should be able to withstand the impact of the crane when it is running at full load. Cranes should be installed with overload limiters and Overspeed and out-of-control protection devices.
(5) The zero position protection of the bridge crane should be intact.
7. Safety facilities
(1) In addition to the electric hoist operated on the ground, all other types of cranes and elevators (including elevators) should be equipped with audio signal devices, and passenger elevators should be equipped with audio alarm devices.
(2) The three phases of the main sliding line of the crane should be equipped with indicator lights, and the colors are yellow, green and red. When the rail length is 50m, indicator lights should be installed at both ends of the sliding line, and an indicator light for power transmission in the driver’s cab should be installed under the main switch knife of the power supply.
(3) The crane cab lighting should adopt 24V and 36V safety voltage.
(4) Lighting power supply should be an independent power supply.
8. Electrical settings
(1) The crane power supply should adopt T-s or tn– system, and the crane rail track should be closely connected with the PE line.
(2) The metal shells of various electrical equipment and facilities on the crane should be well connected with the metal structure of the whole machine, otherwise connecting lines should be added.
(3) Repeated grounding measures should be adopted for the crane track. When the track length is greater than 150m, two groundings should be set on the diagonal line of the track. However, it is not required when there is an existing power grid within ≤50m from the work site.
(4) The two rails of the crane should be firmly connected by connecting wires. The joints of the tracks at the same end shall be welded with jumper wires (except for the tracks on the steel girder frame). Cross-section requirements for connecting wires and jumper wires: round steel ≥ 30mm (6~8mm), flat steel ≥ 150mm2 (3mm50mm or 4mm×40mm)
(5) The PE line of the elevator should be directly connected to the general ground of the machine room, and it is not allowed to be connected in series.
(6) The installation of electrical equipment and lines conforms to the requirements of the regulations, without aging, damage, bare electrical points, or temporary wires.
9. Protective cover, guardrail, guard plate
(1) The exposed movable parts on the crane that may hurt people, such as couplings, sprockets and chains, transmission belts, pulleys, protruding pins, etc., should be equipped with protective covers.
(2) Protective railings should be installed on the outside of the crane that may cause people to fall. The height of the guardrail should be 1050mm, the spacing between the columns should be ≤100mm, and the spacing between the crossbars should be 350mm. The height of the bottom panel is 70mm (kick).
(3) The slide line guard plate shall be installed under the slide line end beam of the bridge crane trolley to prevent the slings from touching (except for the safety slide line that has been safely closed).
(4) The front edge of the crane wheel should be equipped with a rail sweeping plate, the distance from the rail surface is ≤10mm.
(5) The crane walkway plate should be welded with checkered steel plates with a thickness ≥ 4mm, and there should be no warping, skewing, severe corrosion, or desoldering. There should be no reserved holes in the room. If small objects may fall, the hole diameter should be ≤50mm
10. Rain cover, anchoring device
The rail clamp or anchoring device of the open-air crane should be flexible and reliable, and the electrical control part should have a rainproof cover. The aisle slab shall have drainage holes with a hypothetical dry diameter of 50mm.
11. Safety signs, fire fighting equipment
(1) The ton signboard of the rated lifting capacity should be hung in a conspicuous position. The outriggers of the mobile crane, the end of the jib, the counterweight of the slewing, the side plate of the hook pulley, etc., shall be painted in the color of the safety mark.
(2) The driver’s cab and elevator machine room should be equipped with small dry powder fire extinguishers, which should be used within the validity period and placed in safe and reliable locations.
(1) The slings should be centrally stored at several locations and managed and maintained by special personnel. The storage point has a label with optional specifications and corresponding loads.
(2) The penetration length of the pipa head of the bundled steel wire rope is 15 times the diameter of the rope, and not less than 300mm (3) There should be no cracks, no plastic deformation, and excessive wear on the clamps, fixtures, poles, and chains.