AbstractŠIMEK, M., HAVIAROVÁ E., ECKELMAN C.: The end distance eff ect of knock-down furniture fasteners on bending moment resistance of corner joints. Acta univ. agric. et silvic. Mendel. Brun., 2008, LVI, No. 2, pp. 203-210 The goal of this paper is to investigate the eff ect of the end distance of cam lock fasteners on the bending moment resistance of knock-down corner joints. The preliminary study of knock-down furniture assembly plans was done in order to discover the manufacturers' fastener typical usage in case construction. Laminated particleboard, cam fasteners and wooden dowels were used for specimen construction. L-shaped joint specimens 760 mm in length were tested by pressing the joint members together -also called a compression test in the angle plane. The study results showed that cam fasteners with end distance of 60 mm from the member edges perform the best.bending moment resistance, corner joint, end distance, cam fastener, wooden dowelThe joinery for knock-down furniture has been developed and used for almost half century. A large variety of connectors for knock-down furniture exists, including cam locking types, screw in types (e.g. confi rmat, trapez), bolt tightening types (e.g. cross dowels), bracket types, hook types, and dowels used without glue. The mechanical strength of furniture depends mostly on the strength of the joints. Several investigations have been carried out on knock-down fastener joint strength. Among the most important ones are following studies.Smardzewski and Prekrad (2002) studied the stress distribution in knock-down furniture joints by means of experimental testing along with numerical simulation. They tested three diff erent joints (one cam type -VB36M/19 and two trapez types -TZ28 and TZ32S) in combination with two non-glued beech dowels (8x32mm). Their joint corner samples were made out of particleboard. The trapez joints performed the best in the tests. Results showed that the non-glued dowels played an important role in supporting the joint. Numerical simulations determined the distribution of stress in the joints and the bending moment carried by each fastener. Joščák and Černok (2002) tested the load ca paci ty of knock-down furniture joints made from laminated particleboard (18mm thick). Four types of corner joints (confi rmat type, cam type Rafi x, trapez type, and Stabilofi x) were tested in angle plane by pressing the members of the joint together, Fig. 4, and by pulling them apart. The confi rmat type joint performed the best when pressed together. Joints constructed with the Rafi x cam type connector had the lowest moment in compression. Burdurlu et al. (2006) determined the most suitable type of fi tting for the assembly of knock down panel furniture. In his study he used six knockdown furniture fi ttings (two cam types, metal locking type, trapez type, bracket type and pipe type). The direct labor, direct material, direct energy cost, and stopwatch assembly work time in construction of the furniture were observed. Cam fasteners were determined to b...

This study focuses on the use of demountable furniture joints in combination with 38-mm-thick honeycomb panels. These fittings were incorporated into L-shaped corner joints and then tested to determine their bending moment capacity. Overall, seven combinations of demountable fittings were tested. These groups of connectors consisted of solution non-glued, partly-glued connectors, and fully-glued connectors. All of the connectors were positioned in the test samples as they are commonly located in furniture construction. The highest capacities were obtained with glued connectors, followed by partly glued and then non-glued connectors. The difference in capacity between the inside and outside positions was insignificant for the non-glued and fullyglued connectors. A large difference between connectors in different positions was found for the partly glued connectors and for the second type of unglued connectors. The modes of failure were analyzed for each connector, and the possibilities for use in construction are described.

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The objective of the paper is the parametrization and the finite element analysis of mechanical pro­per­ties of a through dovetail joint made with the use of a specific procedure by a 3-axis CNC machine. This corner joint was used for the simulation of the bending load of the joint in the angle plane – by compression, i.e. by pressing the joint together. The deformation fields, the stress distribution, the stiffness and the bending moment of the joints were evaluated. The finite element system ANSYS was used to create two parametric numerical models of the joint. The first one represents an ideal­ly stiff joint – both joint parts have been glued together. The second model includes the contact between the joined parts. This numerical model was used to monitor the response of the joint stiffness to the change of the static friction coefficient. The results of both models were compared both with each other and with similar analyses conducted within the research into ready-to-assemble furniture joints. The results can be employed in the designing of more complex furniture products with higher demands concerning stiffness characteristics, such as furniture for sitting. However, this assumption depends on the correction of the created parametric models by experimental testing.

NOVOTNÝ, M., NEUGEBAUER, R., ŠIMEK, M.: Static analysis of an offi ce desk construction. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 6, pp. 247-254 The objective of the paper is a static analysis of a desk construction and the determination of its probable mechanical behaviour using Finite Element Method. The construction was modelled and numerically analysed in Autocad Inventor 2011 and the stability of the entire desk was calculated with the size and placement of the loading force based on the standards and cited literature. Possible locations and directions of the deformation were analysed and a solution for its prevention was proposed and the stability of the desk as well as the extreme position of the stand were calculated. The verifi cation of the obtained results in an accredited furniture testing lab is planned using a prototype of the offi ce desk.an offi ce desk, construction, steel, numerical simulation, stability A construction of an offi ce desk stand made of steel plate, which enters the production as a large-scale material, has several advantages over commonly used semi-fi nished products. Steel profi les and tubes used in the furniture industry are usually over-dimensioned for the purposes of furniture production as they are primarily designed for engineering or civil engineering. On the other hand, production of castings is usually very expensive and connected with the production of large batches. However, the use of up-to-date CNC processing methods for metals provides furniture producers with a lot of freedom to create their own construction with original design and the optimum use of material properties. In this way, a required combination of attractive design, suitable mechanical properties (construction rigidity, strength, stability, etc.) and lower costs can be obtained when producing small or medium volume of products.The analysed desk construction ( Fig. 3 and Fig. 4) was produced as a prototype using CNC laser cutting, precise CNC press braking (metal parts -stand) and typical furniture production CNC processing (wooden composite materials -desk top).The aim of the study was to establish the probable mechanical behaviour of the offi ce desk, especially the stand, in consequence of the defi ned static loading based on the standards dealing with the testing methods for stability and mechanical resistance of offi ce desk constructions. The study focuses on the analysis of the extreme response (maximum tension) points and the probable breakage points by means of static numerical analysis. These points will be evaluated and based on that we will propose a solution for the achievement of the optimum results. The study further deals with the numerical establishment of the offi ce desk stability and as a consequence provides other possible shape modifi cations.Similar issues related to analyses of furniture construction and numerical simulation of specifi c types of constructions were in the past dealt with by e.g.