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Chainsaw man
Denji's a poor young man who'll do anything for money, even hunting down devils with his pet devil-dog Pochita. He's a simple man with simple dreams, drowning under a mountain of debt. But his sad life gets turned upside down one day when he's betrayed by someone he trusts. Now with the power of a devil inside him, Denji's become a whole new man--Chainsaw Man! -- From volume 1.
BOOK
The Effect of Selected Operation Factors on Cutter Deflection Angles, Instantaneous Speeds, and Accelerations While Cutting Wood with a Petrol Chainsaw
The aim of this study was to determine the influence of initial chain tension, feed force, and wood hardness on the variability of the cutter’s deflection angle during petrol chainsaw operation. Cutting wood with a chainsaw is a complex process that has not been fully elucidated to date. During operation, the position of cutters with respect to the workpiece may vary. The situation is additionally complicated by the fact that chainsaws are powered by one-cylinder gasoline engines characterized by highly variable instantaneous rotational speeds. The experiments involved two types of wood (pine and oak), two initial tension values (tight vs. slack chain), and two feed forces (20 N and 80 N). The cutting process was recorded with a high-speed camera at 12,000 fps to determine cutter deflection angles, instantaneous speeds, and accelerations for all the aforementioned cases. It was found that at the lower feed force the cutter deflection differed depending on the initial chain tension, and a greater cutter deflection angle was observed in pine wood processing. It was also found that speed and acceleration in the Y axis were much lower than in the X axis. Additionally, the rear part of the cutter revealed greater speed variation in the X axis.
Journal Article
Impact of Feed Force and Initial Chain Tension on Chipper Chain Wear in Gasoline-Powered Chainsaws
The aim of the present study was to determine the effects of initial chain tension and feed force on the wear rate of chipper chain cutters in gasoline-powered chainsaws. Wear was assessed by measuring the tip radius as cutter dulling has a considerable influence on chainsaw performance. Tests were carried out for three feed force values: 15 N, 35 N, and 70 N, and for two initial tension settings—a tight chain and a slack chain. The tests also measured cutting efficiency per unit of kerf area. The experiments involved pine wood and were conducted on a specially designed test rig that maintained a constant feed force. The tip radius was determined by means of a microscope and computer image analysis software. Wear intensity over time was evaluated using the dulling coefficient. The results showed that the applied initial chain tension and feed force significantly affected the cutter wear rate, which was significantly higher at lower feed force values. The wear rate was also increased by lower initial chain tension, which can be explained by greater cutter deflection from the kerf plane.
Journal Article
Mini-drone assisted tree canopy sampling: a low-cost and high-precision solution
The collection of tree canopy samples in forest ecosystems has been challenging for researchers and managers during the past decades. Various methods, including pole pruner, tree climber, shooter, throw-line launcher, hydraulic lift (e.g., tower crane) and UAV (unmanned aerial vehicle)-based devices, have been used, however, they are limited by sampling height restrictions, safety hazards to a climber, low retrieving accuracy, high equipment costs, and transportation inconvenience. This study proposed a novel method for collecting tree canopy samples using a portable mini-drone. The mini-drone is operated to pull a traction line across the target branch, drag the retrieving rope to the selected cutting point of the branch, and carry the equipped wire saw or chain saw to cut the canopy sample off. Through on-site testing and field trials, this method was feasible for lower- and middle-canopy sampling (up to 30 meters tall) across most temperate broad-leaved and coniferous tree species. This technique would have great potential in plantation and old-growth forests. Adopting this low-cost mini-drone technique, researchers can collect tree canopy samples safely and efficiently, leading to improvements in relevant physiological and ecological studies focusing on functional traits of branches, leaves, and seeds.
Journal Article
Design solution for a device to determine the energy consumption of sawing wood with chain saws
Cutting wood chips is one of the common work procedures in the course of processing wood with a saw chain. This paper presents the conceptual design of the device and the design of the device for determining the energy demand of such a process. The preparation is designed with the given parameters to achieve the most realistic conditions for sawing wood. It must contain the original cutting device from the STIHL MS 261 chainsaw. It consists of several calculations to determine the cutting moment and the loaded points of the preparation, which define the possible place of damage. In the conceptual design, calculations for cutting force Fr = 924 N and tensile force Fn = 290 N are processed in the work. From the calculated forces, it is possible to determine the resulting stress at the attachment or critical points. For comparison, a finite element method analysis was created in Creo Parametric. The results of the analysis confirm the appropriate selection of material and parameters for the application of the preparation to the test device. The resulting voltages, corresponding to a maximum value of 132 MPa, are negligible for this type of preparation in terms of safety and durability.
Journal Article
Round-Shaped vs. Hexagonally Shaped Saw Chain: Cutting Efficiency and Vibration Comparison
Despite advances in technique and technology, the chainsaw is still the most widely used tool in forestry. For this reason, equipment manufacturers are developing new technical solutions to make working with a chainsaw as easy and efficient as possible. Some examples of this are the development of professional battery-powered chainsaws and the development of new types of saw chains by the leading industry manufacturers. The aim of this paper was to determine the efficiency of the Stihl MSA 300C battery-powered chainsaw equipped with two different types of professional saw chains (Stihl Rapid Super and Stihl Rapid Hexa) when sawing round wood. The efficiency was determined based on measurements of electricity consumption, sawing speed, sawn wood cross-section, and wood chips and dust mass produced during sawing. The second aim was to determine whether there is a difference in measured vibration magnitude between the two tested saw chains. Fresh-fallen European beech (Fagus sylvatica L.) log, approx. 25 cm diameter without pronounced ellipticity, was used for sampling. Results indicate that although the saw chain manufacturer claims the new type of saw chain (Stihl Rapid Hexa) enables greater efficiency of the chainsaw, this was not the case. Results point to a 37% increase in mean sawing time, as well as a 23% increase in energy consumption when using the Rapid Hexa chain, with statistically significant difference (p ≤ 0.05). It should be emphasized that the manual operation of the chainsaw does not allow for a reliable determination of differences in energy consumption caused by changes in saw chain geometry. The advantages of this saw chain are that it is easier to maintain (sharpen) and significantly less wood chips and dust are produced. The measured vibration magnitude shows a statistically significant difference (p ≤ 0.05), i.e., a lower vibration total value on the front handle when using the Stihl Rapid Hexa chain.
Journal Article
The influence of initial tension on blunting of chain saw blades and cutting efficiency
The initial tension of the chainsaw is a decisive factor in making the operator’s work more efficient and at the same time it is a parameter that the operator can adjust and thus affect significantly. This article presents the results of research aimed at determining the impact of the initial chain tension on the blunting of the blade and the cutting efficiency. Two tree species, pine and oak, were examined in our research, which enabled us to also compare the effect of the wood hardness on blade blunting. the wood tested in this study was fresh wood. The measurements were carried out with two different degrees of chain tension: tensioned and loose. We found that both, tension and wood hardness, significantly affect the rate of blunting of the saw blades. The dulling occurs more intensively when working with a loose chain and sawing wood with greater hardness. In the case of too small tension on the saw chain, blunting may occur even more than twice as fast compared to working with a properly tensioned saw. The initial tension and tree species also affect the cutting efficiency with too small an initial tension reducing cutting efficiency.
Journal Article
Extended suicide by use of a chain saw
Injuries caused by chain saws are mostly seen due to accidents. Suicides by chain saws are rare, but some cases have already been described. We present the case of homicide on a child by a chain saw followed by the suicide of his father. For the homicide and the suicide chain saws of different sizes were used. Fatal injuries in the homicide and suicide were located on the neck. Cause of death in both cases was fatal haemorrhage with blood aspiration respectively decapitation. Normally, in suicide by use of chain saws individuals suffering from schizophrenia, major depression and alcohol or drug dependence are concerned. In the presented case, the background was a litigation of a divorced couple for child custody.
Journal Article
