Although there are many types of small cranes and various lifting equipment, there are some basic and universally applicable safety technical requirements. The following conditions should be met during operation and are shared with you as follows: Step/Method 1: The driver of each small crane must be trained, pass the assessment, and hold an operation certificate before operation. 2. When the driver takes over, check the brakes and hooks
Conditions for safe use of small cranes
Although there are many types of small cranes and various types of hoisting products, there are some basic and common Applicable safety technical requirements. The following conditions should be met during operation and are shared with you as follows:
Step/Method 1: The driver of each small crane must be trained, pass the assessment, and hold an operation certificate before operation. 2. When the driver takes over, check the brakes, hooks, wire ropes and safety devices. If abnormal performance is found, it should be eliminated before operation. 3. Before driving, you must ring the bell or call the police. When operating close to people, the sound or alarm should continue to sound. 4. Operation should be carried out according to the command signal. When you hear the emergency stop signal, no matter who sends it, you must execute it immediately. 5: Turn off the main power only after confirming that no one is on or around the crane. If there is a lock or mark on the power circuit breaker, it should be removed by relevant personnel before the power can be turned off. 6. All controller handles should be set to zero before turning off main power. 7. If there is a sudden power outage during work, all controller handles should be returned to zero; before working again, check whether the crane moves normally. 8: When a small crane is running, it is not allowed to stop with a limit switch; for cranes without reverse braking performance, reverse braking is not allowed except in special emergencies. 9. Do not adjust the brakes of the lifting and luffing mechanisms under load. 10: Lifting heavy objects must not go over people's heads, and people are strictly prohibited from standing under the boom. 11. When the lifting weight is close to or reaches the rated lifting weight, the brakes should be checked before lifting, use a small height (200 ~ 300 mm) short-stroke test crane, and then lift smoothly y-12: Lifting liquid metal, harmful liquids, flammable and flammable materials When handling explosives, the crane must be tested at a small height and short stroke first. 13. The lifting speed of heavy objects should be uniform, and emergency braking and sudden descent are not allowed under special circumstances.
Precautions
Do not hang when the weight of the overloaded object is unclear; do not hang up when the signal is unclear; do not hang when tying, hanging or unbalanced may cause slipping; tension Do not hang unclear buried objects; do not hang when heavy objects are pulled diagonally; do not hang when the working site is dark and you cannot clearly see the site, the status of the hanging objects, and the command signal; when the molten steel (molten iron) is overpacked, it will not hang .
Things to note when operating a small crane
Things to note when operating a small crane are shared for your reference:
Steps/Methods
1 : Steel wire rope
(1) The number of broken wires within one lay length should not exceed the requirements in Table 1-9, and the surface wear and corrosion of the steel wire should not exceed 40% of the original diameter (for lifting molten iron or dangerous goods) The scrapping standard for broken steel wires is 1/2 of that of ordinary cranes.
(2) The wire rope should be free of kinks, dead ends, hard bends, plastic deformation, hemp core extrusion and other serious deformations, and should be in good lubrication condition.
(3) The length of the wire rope must ensure that when the hook is lowered to the lowest position (including the pit), no less than 3 turns of the wire rope remain on the drum.
(4) There should be two or more fixed clips at the end of the wire rope.
2: Pulley
(1) The pulley is flexible, smooth and has no cracks, and there are no defects in the rim part and no damage to the wire rope.
(2) The wheel groove wear is uneven by 3 mm. Or the wall thickness is worn to 20% of the original wall thickness, or the groove bottom diameter is reduced to 50% of the wire rope diameter, the pulley should be scrapped.
(3) The pulley guard should be installed firmly without damage or obvious deformation.
3: Hook
(1) The surface should be smooth and free of defects such as breaks and sharp angles. Repair welding is not allowed for defects on the hook.
(2) The hook should be able to rotate flexibly, and the positioning bolts and cotter pins must be tightly tightened.
(3) Cracks are strictly prohibited in the dangerous lower section of the hook and the unloading groove section of the hook tail thread.
(4) The wear of the dangerous section should not exceed 10 times the original size. The hook bushing should not be worn more than 50% of its original size and the mandrel should not be worn more than 50% of its original size.
4: Brake
(1) The action should be flexible and reliable, the adjustment should be moderately tight, and there should be no cracks, plastic deformation and no ends of the spring.
(2) When releasing the brake wheel, the clearance between the brake shoe and the brake wheel should be basically equal. The maximum opening of the braking belt (one side) should be ≤1 mm, and the elevator should be ≤0.7 mm.
(3) The braking friction surface of the brake wheel must not have defects that hinder the braking performance. Must not be stained with oil or paint.
(4) The surface roughness of the wheel should be lt; 1.5 mm. The thickness and wear of the brake rim of the lifting and luffing mechanism should be less than 40% of the original thickness. The wear thickness of the brake rim of other mechanisms should be less than the original thickness. Thickness of 50.
(5) After the crane lifts hot metal, flammable and explosive dangerous goods or sliding hooks, the lifting mechanism should be equipped with two sets of brakes to avoid causing greater danger or loss.
5: Limiting and interlocking devices
(1) The overhang limiter should ensure that when the hook rises. The limit position (electric hoist: 0.3m; double-beam crane: 0.5m) can automatically cut off the power supply. Newly installed cranes should also have lower limit stops.
(2) The operating mechanism should be equipped with a stroke limiter and a mutual inductance limiter to ensure that the two cranes are 0.5 m apart and the power supply is automatically cut off when the crane is 0.5-3 m away from the end (depending on the tonnage) .
(3) When the elevator (or elevator) car (car) spans 30-100 mm between the upper and lower stations, the overtravel switch should cut off the control circuit; the limit switch should cut off the main power supply. It cannot automatically reset when standing at a horizontal position of 130-250 mm. Limit switches are not allowed to use knife switches.
(4) The luffing crane should be equipped with a limiting device to prevent the boom from tilting forward and backward within the maximum and minimum range. 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) The door cabin interlocking protection device should be installed outside the bridge crane cab door, the warehouse door leading to the bridge and the end beam doors on both sides of the crane; the elevator (or elevator) landing door must Equipped with an electromechanical interlocking device, the car door should be equipped with an electrical interlocking device; the safety door on the top of the passenger elevator car must be equipped with an interlocking protection device; the door of the passenger elevator should be equipped with a sensitive safety touch panel.
(6) Hoisting machinery for outdoor operations. Various limit switches and interlocking electrical parts should be protected against rain and snow.
6. Parking protection device
(1) Various switches have good contact, reliable operation and easy operation. In an emergency, the power supply can be cut off quickly (the button box of the electric hoist operated on the ground should also work closely with the stop switch).
(2) Buffers should be installed on the operating mechanisms of cranes and trolleys, on the sides of the four ends of the track terminal columns, and at the bottom limit of the stroke of the elevator (or lift).
(3) Various buffers should be installed firmly. Use rubber buffers, the thickness of the trolley is 50 ~ 60 mm, and the thickness of the trolley is 100 ~ 200 mm; if hardwood blocks are used, the surface of the wood blocks should be equipped with rubber.
(4) The rail terminal brake should be able to withstand the impact of the crane when it is fully loaded. Cranes of 50 t and above should be equipped with overload limiters. Elevators should be equipped with load limiters and overspeed and runaway protection devices.
(5) The zero position protection of the bridge crane should be intact.
7. Signaling and lighting
(1) Except for electric hoists operated on the ground, all other cranes and elevators (elevators) should be equipped with audio signaling devices, and manned elevators should be equipped with Audio alarm device.
(2) The three phases of the crane's main slide line should be equipped with yellow, green and red indicator lights. When the rail length is >50 m, indicator lights should be installed at both ends of the slide line. The power transmission indicator light in the cab should be set below the main electric knife.
(3) Crane cab lighting should use 24V and 36V safe voltage. The lighting under the bridge should use a shock-proof deep bowl lampshade, and a 10 mm x 10 heat-resistant protective net should be installed under the lampshade. (4) The lighting power supply should be an independent power supply.
8: PE lines and electrical equipment
(1) The power supply should use TN-S or TN-C-S system, and the crane track should be closely connected to the PE line.
(2) The metal shells of various electrical equipment facilities on the crane should be well connected with the metal structure of the entire machine; otherwise, connecting wires should be added.
(3) The crane track should adopt repeated grounding measures. When the track length exceeds 150 m, two grounding points should be set at the diagonal of the track. However, this is not required when the existing power grid is repeatedly grounded within a range of ≤50 m from the work site.
(4) The two tracks of the crane should be firmly connected by connecting lines. The joints of rails at the same end (except rails on steel beam frames) should be cross-welded. Cross-section requirements for connecting wires and jumpers: round steel ≥ 30mm2 (φ 6 ~ φ 8mm), flat steel ≥ 10mm2 (3mm×50mm or 4 mm×40mm).
(5) The PE wire of the elevator (elevator room) should be directly connected to the general ground wire of the machine room, and serial connection is not allowed.
(6) The installation of electrical equipment and circuits complies with specification requirements and is free of aging, damage, exposed electrical points and temporary wires.
9: Guardrails and guard plates
(1) Exposed moving parts of the crane that may injure people. Such as couplings, sprockets and chains, transmission belts, pulleys, protruding pins, etc. , should be equipped with a protective cover.
(2) Protective railings should be installed on the outside of the crane to prevent people from falling. The height of the guardrail is ≥1050 mm, the distance between the columns is ≤100 mm, the distance between the crossbars is 350~380 mm, and a bottom skirt (skirt board) is installed at the bottom.
(3) A sliding guard plate should be installed under the sliding end beam of the bridge crane trolley to prevent contact with the sling (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, and the rail sweeping plate should be ≤10 mm from the rail surface.
(5) The crane walkway plate should be welded with pattern steel plates with a thickness of ≥4 mm, and there should be no warping, skew, severe corrosion or desoldering. If there is no possibility of small objects falling, there should be no reserved holes in the room. The hole diameter should be ≤50mm.
10: Rain cover and anchoring device
The rail clamp or anchoring device of the open-air crane should be flexible and reliable, and the electronic control part should have a rainproof cover. The walkway should be provided with several drainage holes with a diameter of 50 mm.
11: Safety signs and fire-fighting equipment
(1) The tonnage nameplate of the rated lifting capacity should be hung in a conspicuous position. Outriggers, cantilever ends, slewing counterweights, hook pulley side plates, etc. The outer shell of the mobile crane should be painted with safety signs.
(2) The driver's cab and elevator room should be equipped with small dry powder fire extinguishers, which should be used within the validity period and placed safely and reliably.
12: Slings
(1) Slings should be stored in several locations and managed and maintained by dedicated personnel. Storage points are marked with the selected size and corresponding load.
(2) The penetration length of the pipa head of the binding wire rope is 15 times the rope diameter and not less than 300 mm.
(3) Clamps, fixtures, poles and chains should be free of cracks, plastic deformation and excessive wear.
Conditions for safe use of small cranes @2019