The study identifies the level of vibration activity in an impact tool for soil compaction. The subject of the study was a hand operated pneumatic tool, one that is currently manufactured and used in Poland. The displacements of the tool handle which characterize the level of vibration transmitted from the tool to the operator's hand-arm-system were measured. Experimental tests were carried out on the vibration isolation system with the aim to reduce the exposure of operators to vibration and their risk of vibration disease. The aim of the analysis was to optimize the design features of the damper for the choice of stiffness of the elastic system that minimizes the level of vibration transmitted from the tool to the operator. The vibration isolation system was tested at a measuring stand equipped with a hydraulic pulsator with a control system enabling simulation of a working cycle for the soil being compacted. It was possible to change the kinematic parameters of the working cycle within a wide range of amplitudes and frequencies, using a measuring set. Elastic systems for vibration isolators with different stiffness parameters were made and tested.
W artykule przedstawiono weryfikację doświadczalną teoretycznych przebiegów ciśnień w komorach ubijaka pneumatycznego, uzyskanych w oparciu o model matematyczny [1, 2], Wskazano możliwe przyczyny rozbieżności oraz potrzebę nowego opisu dynamiki tego narzędzia.
EN
In the paper an experimental verification of theoretical pressure runs in chambers of a pneumatic rammer were presented, obtained on base of a mathematical model [1,2]. All the possible reasons of divergences were indicated as well as the need of new specification of dynamics of this tool.
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Przedstawiono metodykę projektowania układów wibroizolacji pneumatycznych narzędzi udarowych, uwzględniającą analizę stanu wibroaktywności narzędzia, przemiany termodynamiczne oraz identyfikację poziomu przyspieszeń uchwytu narzędzia. Opracowano model matematyczny cech dynamicznych zespołu narzędzie udarowe - wibroizolator. Zaprojektowano układ wibroizolacji skutecznie redukujący poziom transmisji drgań do organizmu operatora.
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The paper presents numerical modeling and simulation of impact tool with contact of substitute soil. Neoprene plate is used as the substitute soil. The results of numerical simulation are compared with experimental results. FEM System ABAQUS/Explicit is applied to solve the numerical problem.
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This work presents a methodical approach to design problems in designing vibration isolation systems of impact tools. Experiments and analysis of impulses acting on the tool body enabled to develop a two-stage vibration isolation system effectively limiting the level of vibration transmitted to the operator's hand - arm system.
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The modelling enables analysis of various design solutions even in the design phase, and makes it possible to study the influence of specific design parameters on the performance of the machine designed. Mathematical models representing the dynamics of the hand-arm system, together with models of impact tools, enable simulation analyses and determination of the construction features of the tool. This paper discusses the harmful influence of vibration on human operators and the danger of the Vibration Syndrome. It also presents a description of a soil compacting tool constructed at the Chair of Machine Design Fundamentals at the Poznań University of Technology, as well as single and multi-mass mathematical models of dynamic properties of the vibration isolator, including models of the operator's hand and the soil compacted. Additionally, the paper discusses the results of simulation analyses of the selection of specific parameters of vibration isolation systems for pneumatic tools. The mathematical models enable the design of vibration isolators of high dampening efficiency for the vibration transmitted into the human body, without loss of technological efficiency of the actual technological operation.
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