Analysis of picking-and-cutting device of roll-and-pack machine of LP-19A type
- Added: 16.06.2021
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In this course work, an analysis of the gripping and cutting device of the LP-19A type roll-and-bag machine was carried out. The calculation of kinematic, geometric and strength parameters of the machine assembly was made. During the operation, problems arose with the strength calculation of the unit, it was necessary to reduce the cutting speed, the chain chosen at the beginning of the calculations could not withstand the load. According to the structural part, the design of the saw unit was drawn.
1. General part
1.2 Purpose and scope of the machine
1.2 Overview of design features of the machine similar to those designed for the purpose
1.3 Selection and description of the basic layout and design of individual components of the designed machine
2. Structural part
2.1 Selection and calculation of basic geometrical parameters of machine working elements
2.2 Calculation of processing modes (tooth feed, cutting and feed speed, etc.)
2.3 Calculation of forces acting on machine working elements
2.4 Calculation of drive engine power and selection
2.5 Calculation of kinematics of working elements drive
2.6 Strength calculation of machine assembly
3. Process Part
3.1 Calculation, unit processing
3.2 Calculation of the replaceable capacity of the machine
3.3 Description of the manufacturing process where the designed machine is used
4. Machine Control System
5. Basic rules of machine technical operation
6. Machine Safety
7. Comparative technical characteristics of the designed machine with analogues
List of literature
One method of rolling wood is a roll-packing machine, which works in conjunction with a number of other unique devices intended for roll work. Usually a roll-and-pack machine is the initial link, the next links are a track tractor, then a machine performing cutting of knots and a loader.
At the very beginning of the work, a wood roll takes place, which includes separating the tree from the stump, as well as trimming the bitches and tops. Since these operations are considered especially dangerous, manual labor is better replaced by a mechanized method of work. After all, at this stage anything can happen, which can lead to injuries and more serious consequences. For these purposes, a roll-packing machine was created, the performance of work on which requires the participation of only one person - the operator of this machine, and therefore traumatic cases on the timber mill in this case are very rare.
The roll-and-pack machine is a device having a cabin and a handle with a grip. At the bottom of the manipulator is a RAM, which allows you to simultaneously pick up the tree and saw it. If trees stand nearby, you can grab several at once, which allows you to increase labor productivity. A roll-packing machine cuts trees, moving from one loading platform to another and puts them in packs.
Description of VPM LP-19A manufacturing process
The process cycle during cutting and laying of wood by the roll-and-pack machine LP19A consists of the following techniques: VPM comes to the technological parking lot, after which, using a hydraulic manipulator, the gripping device is guided to the tree. The upper and lower grips are clamped, the lever system in the upper part of the RAM is tensioned and the wood is cut by a saw. The sawn tree is pulled closer to the machine to reduce the risk of overturning. After that, by turning the platform, the tree is transferred to the place of its laying. The tree is tilted, the clips are opened, and the tree is stacked on the ground.
The cycle is repeated until the departure of the manipulator (8 m) allows the roll to be carried out. When the nearest trees are sawn, the car moves to the next technological parking lot.
The aiming of the gripping device on wood consists in moving this device from machine to wood (horizontal aiming) and setting the cutting member to the specified height (vertical aiming). Aiming is performed by simultaneous lowering of boom and extension of handle. During aiming it is unacceptable to force the manipulator on the barrel and bend the barrel. After finishing the aiming, i.e. after touching the upper and lower prisms of the tree trunk at a given height, the wood is clamped with clamping levers. To make it easier to cut a tree, the trunk is pulled up (tension).
The end of sawing is determined by a light push, which is transmitted to the machine when a tree previously stretched up is separated from the stump. If the saw is clamped in the cut, the driver shall remove the saw to its initial position. You can release the tire from the clamp by carefully turning the rack away from yourself. Then, by tensioning the barrel or turning the grip post, eliminate the cause of the clamp and, moving the post along the barrel up by 3... 5 cm, turn on the clipping mechanism again.
Pull-up is a preparatory technique that facilitates the rotation of the platform with a tree. Pulling reduces the tipping moment, the load on the machine and allows to eliminate the adhesion of the crown of cut wood with growing trees.
Turning of the platform with a tree is carried out on the departure (counting from the axis of rotation to the vertical axis of the tree) 4... 6 m. During the rotation, the driver must monitor the position of the tree, preventing its excessive inclination, adhesion to the crown of standing trees and touching the gripping device of stumps, walleye and other obstacles.
The package laying consists in installation of the manipulator of the plane of the package axis, correction of the manipulator departure, overturning the tree with the apex "from itself" and dropping it into the package. Installation of the manipulator in the plane of the packet axis consists in stopping the platform at the moment when the manipulator with wood is above the packet.
The tree is tilted by the gripping device. Trees are tilted to angles, at which it is possible on the one hand to reduce the force of impact of the tree when its pack falls, to prevent slipping of the tree along clamping levers down, and on the other hand to reduce the effect of the tipping moment from the tree on the machine.
When the machine operates in loose snow up to 50 cm deep, the snow is compacted by lowering the gripping device vertically along the barrel. In case of deeper or denser snow, the gripping device is deepened by means of additional techniques. The RAM with closed levers is brought to the tree, descends as far as possible, compacting the snow, then by turning the platform or repeatedly pulling the handle, the snow is drained to the required depth.
Car moves should be made only in front. Reverse movement of the machine is allowed as an exception for short distances.
Basic rules for technical operation of VPM LP-19A
The roll machine must be technological, fit well into the flow through the forest section. This is primarily a flexible process connection between the roll machine and subsequent machines in the system. It is necessary that the roll does not restrain the trefoil, the trefoil in turn - the roll. At a minimum, it is necessary to roll trees so that between them and the wall of the forest there is a passage for the roller machine itself on its next voyage. A prerequisite is also the order of felling of trees, which would create the most favorable conditions for the formation of a pack and its cracking.
When machining trees, it is necessary to observe "General safety requirements when performing logging operations by machines (mechanisms)." In process rolls of trees between VM, VPM, VTM and other cars working at a cutting area the safe distance not less than 50 m has to be observed. Cutting by car of a tree which diameter is more than maximum thickness specified in technical data sheet of the car is not allowed. It is not allowed to lay trees with roots, perform loading and unloading works, if the machine does not have special equipment for this purpose. It is possible to be under the hydraulic manipulator only if the RAM rests on the ground. When starting work, the operator must make sure that there are no people in the danger zone and sound a signal. Since the machine roll of the forest is allowed around the clock, standard illumination of working areas should be provided in the dark, and drivers should have lights with which signals can be sent and safely move around the forest area in case of an emergency.
Basic Safety Rules for Scaffolding
Logging is one of the most traumatic operations in the logging process. The main causes of injuries of workers on the roll are improper performance of roll techniques, violation of the established 50-meter safety zone and the accepted cutting technology, as well as inattentive attitude to the establishment of dangerous trees and the requirements for their landing.
The rules of safety allow the development of forests only after preparing their territory for cutting: harvesting dry, rotten, hovering and other dangerous trees throughout the area. The workers who are to develop the forestry should be familiarized by the foreman before starting work with the technological map for the development of the forestry. Without pre-harvesting of dangerous trees, the development of woodlands is allowed: during machine rolling of the forest; with the number of dangerous trees reaching 20 percent or more of their total number in the forest area (such forests are developed according to the rules of wind-brown forests).
Rolling of trees with petrol-powered saws on wind-whirlpoolomous forest sections and burners, with an oncoming wind at a speed of more than 4.5 m/s (thin branches of trees are set in motion), on slopes with a steepness of 20 ° and higher, when rolling dangerous trees in preparation for development, only two workers are allowed: a roller with an assistant.
With selective, gradual, selective and sanitary logging and logging, the roll must be made into gaps between trees. Trees that interfere with the roll and trellis of stigmatized trees should be cut down. Trees in the nests must be turned towards their natural inclination. Each tree must be brought down separately. Trees with a fork must be laid in one of the sides perpendicular to the fork plane. Hovering trees must be lowered with the help of a tractor, a special winch or horse traction with a cable length of at least 30 m.
The place where trees roll at a distance of 50 m should be protected by portable prohibition signs "Passage and passage are prohibited - forest roll!" Signs are installed on the wolf, trails and roads leading to the roll site. In the fifty-meter danger zone, only the roller and its assistant can be located. It is forbidden to roll trees when people, animals, machines and mechanisms are in the danger zone.
The roller and its assistant are allowed to work on the tree roll when using personal protective equipment and is mandatory in protective helmets, a serviceable tool and in the presence of roller devices. It is forbidden to put trees on the forest wall, in the gaps between standing trees, without backfilling and leaving the required one. Group felling of trees by knocking down one or more sawn trees by another, as well as leaving sawn or underfilled trees are not allowed.
Before starting the engine, make sure that the saw chain does not touch any objects. When backing and sawing trees, you must first bring the stop into contact with the trunk, and then the sawing machine. It is possible to release the clamped saw tire in the propyl only after the engine is completely stopped. You can transfer the saw from one tree to another only when the engine is idling when the saw chain does not move. With the approach of a thunderstorm, at a wind speed of more than 11 m/s (thick branches of trees swing) and visibility of less than 50 m, the rollers must stop rolling and leave the forest.
When machining trees, it is necessary to observe "General safety requirements when performing logging operations by machines (mechanisms)." In process rolls of trees between VM, VPM, VTM and other cars working at a cutting area the safe distance not less than 50 m has to be observed. It is not allowed for the machine to sawn wood, the diameter of which is more than the maximum thickness specified in the technical certificate of the machine. It is not allowed to lay trees with roots, perform loading and unloading works, if the machine does not have special equipment for this purpose. When starting work, the operator must make sure that there are no people in the danger zone and sound a signal. Since the machine roll of the forest is allowed around the clock, standard illumination of working areas should be provided in the dark, and drivers should have lights with which signals can be sent and safely move around the forest area in case of an emergency.
High productivity of the workers employed on the timber roll is ensured only under safe working conditions. At least two people shall be present on the timber seam during the forestry works. Single work on the forest section is not allowed.
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