The forklift lifting system is a direct working device for loading and unloading operations of the forklift. The unloading and stacking of the goods are finally completed by it, so it is the most important part of the forklift. In use, it is necessary to strengthen the maintenance frequently to maintain its good technical condition.
Disassembly and adjustment
Inner and outer gantry. There is relative movement between the main components of the forklift lifting system. Among them, the inner and outer gantry form a sports pair, and the fork and inner gantry form a sports pair. In order to improve the motion accuracy of each motion pair, reduce the friction between each moving member, reduce vibration noise, and improve the lateral stability of the vehicle when the fork is unloading, the inner and outer masts and the side rollers on the fork frame are adjusted Gasket. Through the adjustment of the gasket, the gap between the fork roller side roller and the inner gantry, and the gap between the inner and outer gantry rollers and the inner and outer gantry, under the condition of relative movement, the gap value is not more than 1mm. When the clearance of the roller or coincident gantry exceeds the clearance specified in the design, the roller needs to be adjusted or replaced to ensure the clearance of rolling or sliding, reduce the impact sound, and prevent the goods from sliding off the fork. The size (thickness) of the cross-section flange of the mast is reduced by more than 1mm or the transverse size of the entire mast structure (width direction) is greater than the specified size by more than 2.5mm. When the mast is deformed or warped, the mast must be replaced to ensure safe use. .
Guide pulley and lifting chain. When the chain is assembled, the tension of the two chains should be equal, the load should be as uniform as possible, and there should be no distortion, and the two sprockets can rotate flexibly after installation. The thickness and length of the paired forks should be approximately equal. The angle between the vertical and horizontal sections of the two forks should also be the same. After the two forks are installed on the fork frame, the upper plane should be kept in the same plane. The maximum length of the lifting chain should be adjusted when the fork lifts to the maximum lifting height (that is, the lifting cylinder piston rises to the upper limit). The adjusted lifting chain should not be too tight, usually at a height of lm, with a 5ON force For the chain, the maximum deflection deformation is 2Omm is qualified. Each time maintenance is performed, grease should be added to the inside and outside of the channel steel and the chain sprocket to ensure good lubrication and reduce the friction of each sports pair. In a wide-field lifting system, the strokes of the two lifting cylinders (cylinders) should be equal, and the respective oil inlet lines should be unobstructed. The upper end surfaces of the plunger rods of the two cylinders should be in contact with the inner mast and sprocket bracket at the same time.
Fork frame. Since the installation size between the hook and the fork frame has been standardized, various attachments have the same hook as the fork. Therefore, the plate fork can easily replace the attachment. In order to allow the fork or attachment to be loaded or unloaded from the fork frame, when the fork frame is equipped with a shelf, the gap in the middle of the lower baffle plate can be used to install and remove the fork. In order to position the fork or attachment on the fork frame and adjust the distance between the forks, a number of symmetrical positioning holes and positioning grooves on the upper baffle plate can be used to locate by the positioning pins with springs on the upper end of the fork. When the fork is an articulated type, the fork frame is made into a slide bar type. There are two left and right round shafts in the fork frame. Each round shaft is covered with a fork. The fork can slide on the round shaft to adjust the two. The distance between the forks, when installing and disassembling the forks, the round shaft needs to be removed, and the forks are positioned on the round shafts with bayonet pins.
Fork. Pay attention to the options when installing the forklift. The thickness and length of the paired forks should be approximately equal. The angle between the vertical section and the horizontal section of the two forks should also be the same. After the fork is mounted on the fork frame, the upper plane of the two forks should be kept in the same plane, and there should be no high and low misalignment.
Maintenance of lifting system
Technical requirements for lifting systems. The door frame should be free of cracks, defects that affect strength and rigidity, and the amount of deformation should not exceed the allowable value of the design. The portal frame generally adopts an overlapping structure. The internal and external portals should be well coordinated, sliding flexibly, and without jamming.
Guide pulley frame should be installed correctly and firmly. The pulley and pulley shaft should be free of cracks and defects, and the wear of the wheel groove should not exceed 10% of the original design thickness. It should be matched with the guide pulley frame to make the pulley rotate flexibly and reliably. Chain specifications and models should meet design requirements. The chain plate and shaft should be free of cracks and deformations, and keep the transmission flexible and reliable.
Auxiliary frame guide wheel frame should be intact, no cracks, good cooperation with the door frame, can slide flexibly on the door frame, stable without jamming. The guide surface of the beam of the guide wheel frame should be smooth and smooth, so that the fork can move smoothly and reliably in the lateral direction. The fork should have sufficient strength and rigidity, and cooperate well with the guide beam crossbeam. Attachment racks should generally be fitted with protective frames made of flat steel and kept intact and free of deformation. The mast and tilt cylinder should be firmly connected with the frame, with good coordination, reliable locking and flexible rotation.
The door frame must not be deformed and the weld seam is de-welded. The inner door frame and the outer door frame, the attachment frame and the inner door frame rise and fall relatively smoothly. The cooperation gap between the door frame and the roller should not be greater than 1.5mm, and the sliding is good without jamming. The rotation of the roller should be recorded, the roller and the shaft should be free of cracks and defects, and the wear of the wheel groove should not be greater than 10% of the original size. The tension of the two lifting chains should be even, without distortion, and the ends are firmly connected; the clearance between the link pin and the bearing hole must not be too large. The sprocket rotation should be flexible, the depth of the groove should not exceed 0.5mm of the original size; the attachment frame should not have serious deformation and welding seam opening phenomenon.
The surface of the fork must be free of cracks, and the welds of all parts must not be de-welded. The fork root angle should not be greater than 93°, and the thickness should not be less than 90% of the original size; the height of the left and right fork tips should not exceed 3% of the length of the fork horizontal section; the positioning of the fork should be reliable, the support surface of the fork hook, The positioning surface must not have obvious defects; the clearance between the fork and the attachment frame should not be too large, and the movement should be smooth.
Worn and broken parts and maintenance. In the use of forklifts, the common dangerous section of the fork is the vertical section near the elbow at the lower part of the vertical section and the welding place between the upper end of the vertical section of the fork and the upper hook, all of which are dangerous places that are prone to breakage. In particular, forklift drivers often operate in violation of regulations, use a fork on the front of the fork to lift or pick up the ground cargo alone, causing the fork or fork to bend and deform, or even (after the cargo is overloaded) the root of the vertical section is broken, which will cause serious economics. loss.
Overhaul of common forklift forks. According to national standards, the use of forks should be inspected once a year; forklifts used under harsh working conditions need to be inspected more frequently to find any defects or permanent deformation, and adopt relevant technical measures to eliminate hidden dangers. The inspection of the forklift and fork shall be carried out by professional technicians. It is found that the fork has any signs that impede safe use, failure and obvious deformation and other defects. It must be stopped. It can only be used after it has been strictly repaired and passed the test.
Fork cracks on the fork surface (especially the fork root, upper hook, lower hook and the connection of the vertical section), once the height difference between the two fork tips exceeds 3% of the length of the horizontal section, the fork must be stopped. During use, the positioning pin must be in good maintenance and normal working conditions in place. If any faults are found, the fork must be stopped before being repaired. Periodically and thoroughly check the degree of wear of the horizontal and vertical sections of the fork, especially the root of the fork. If the thickness of the fork is reduced to 90%, it should also be stopped. The wear, backlog and other local deformations of the upper hook support surface of the fork and the positioning surfaces of the upper and lower hooks cause the gap between the fork and the fork frame to increase and must be repaired before it can be used.
Unconditional conditions, it is best to replace the fork with a new one, and it is not allowed to be used. Even after the fork is welded and repaired, it can only be put into use after undergoing strict technical standard inspection and meeting the original factory specifications.
Maintenance of working equipment of forklift
During the maintenance of chains and pulleys, there should be no cracks and deformations on the chains, and the rotation must be flexible. The extension of every 20 links does not exceed the specified value (8mm). The wear of the chain pin shall not exceed 5% of the original diameter, and there shall be no severe bending, fatigue cracks and corrosion. If it exceeds the allowable conditions, it should be replaced. If there is uneven wear on the pulley surface, the difference between the outer diameters of the two pulleys is greater than 0.2mm, and there are steps or indentations on the pulley surface, which affects the normal operation of the chain. It should be replaced.
When inspecting the main and side rollers, check the wear marks of the main and side rollers should be even. The wear limit is along the diameter, the main roller is 1.0 mm, and the side roller is 0.5 mm. Otherwise it should be replaced. When the inner and outer masts are inspected and repaired, the inner and outer masts must be straight, and the straightness should not exceed 1mm within the full length, and the use limit is 3mm. Otherwise, it should be repaired. Check for cracks with magnetic flaw detection and percussion methods. If so, it should be repaired. Check for deformation or distortion. When the bending deformation exceeds 1.5mm in the full length range, the lateral width difference exceeds 1.5mm, and the bending deformation of the inner door top plate exceeds 2.0mm, it should be corrected. When the overall deformation is serious, and the size of the guide rail opening exceeds the wear limit, it should be scrapped. When the inner side and inner side guide rails wear and rise up to 2mm on each side, the guide rails should be replaced or trimmed before use.
When the working device is assembled for inspection and adjustment, first check and adjust the front and rear clearances of the inner and outer gantry. Optional use of rollers with a clearance of less than 1mm for assembly. When assembling, after getting the proper clearance, operate the lifting handle to make the inner gantry run up and down. It should run smoothly, and the rollers rotate freely and evenly. The second is the inspection and adjustment of the left and right gaps of the inner and outer gantry. According to the required size, adjust the installation position of the lateral rollers by adding or subtracting shims to ensure that the clearance value between the rollers and the inner and outer walls of the inner and outer mast channel steel is satisfied (0.1-1 at the highest position of the inner mast) .Omm, the lowest position of the inner mast is 0.1-1.5mm); the third is the adjustment of the left and right gap of the fork frame, which is the same as the adjustment of the left and right gap of the inner and outer mast, except that the gap value is 0.1-1.Omm everywhere. After all adjustments are made, lift the fork frame and inner mast to see if the movement is stable. To descend from the maximum height, it is required that the inner mast and free fork fall freely. Otherwise, it should be readjusted; the fourth is the adjustment of the lifting chain. The lifting chain is too long, and the lifting height cannot meet the requirements; too short will cause a serious accident that the fork frame will run out of the channel steel of the inner gantry; the two chains will be loose and tight, causing one chain to overload and eccentrically load, causing the fork frame and The movement of the inner mast is not smooth and flexible. Therefore, the two chains must be adjusted. The method is: park the forklift on a flat field, the gantry is vertical, lower the fork to the ground, and lift the cylinder piston (plunger) to the bottom dead center. Install the chain, one end of the two chains is connected to the fork frame and locked. Make the chain bypass the pulley, and connect the other end to the flange of the lifting cylinder or the beam of the outer mast, and adjust the length of the chain with hinge bolts. Use your finger at 1000mm from the ground to 49N
Is based on the chain, the chain travel distance is less than 20mm, adjust another chain in the same way. After adjusting the two chains, lift the fork and check the tightness and length of the two chains.
