• An ergonomic seat or bed must be capable of supporting optimally and evenly the user's body for sustained periods of time. The objective of the performed investigations was to ascertain the impact of natural ag-

A robotization of assembly is the real implementation of Industry 4.0 in the furniture industry. The robotization objective is to obtain favorable values of production process parameters (performance, productivity, quality) and to improve human wellbeing at work. Our aim was to present and compare the quality parameters of a selected furniture production process, performed in a very long series, containing more than 30 thousand products. The analysis included the results of the long-term measurements of the quality level of upholstery frames produced by the modified and improved, on the basis of operational conclusions, robotized line for the serial production of upholstery frames and by the simultaneously used nonrobotic line for assembly of frames of the same construction. The results obtained show that robotized assembly leads to a much lower percentage of defective products than in the case of the nonrobotic technology, the causes and types of defects in the products are also different, and it is easier to prevent these defects and remove them. The cognitive findings identified problems and challenges, not found in traditional technologies, caused by the using of manufacturing robots in furniture production.

This paper presents an approach to the design of an upholstered furniture frame using the finite element method and empirical studies. Three-dimensional discrete models of upholstered furniture frames were developed taking into account orthotropic properties of solid pine wood (Pinus sylvestris L.) without and with details strengthening their structure in the form of glue joints and upholstery staples. Using the CAE Autodesk Inventor Nastran finite element method, linear static analyses were performed by simulating normative loading. The finite element method was performed considering the experimentally determined stiffness coefficients of the PCAC adhesive and staple joints. As a result, stress, displacement, and equivalent strain distributions were obtained for upholstered furniture frame models with stapled corner joints. The deformation and strength behavior of the upholstered furniture frames was improved by reinforcing with a wood strip. A new approach to the design of upholstered furniture frame frames using the FEM method with stapled component connections was developed and tested. The results of the study can be applied in the optimization of upholstered furniture construction.

This paper presents the strength properties of wooden trusses. The proposed solutions may constitute an alternative to currently produced trusses, in cases when posts and cross braces are joined with flanges using punched metal plate fasteners. Glued carpentry joints, although requiring a more complicated manufacturing process, on the one hand promote a more rational utilisation of available structural timber resources, while on the other hand they restrict the use of metal fasteners. The results of the conducted analyses show that the proposed solutions at the current stage of research are characterised by an approx. 30% lower static bending strength compared to trusses manufactured using punched metal plate fasteners. However, these solutions make it possible to produce trusses with load-bearing capacities comparable to that of structural timber of grade C24 and stiffness slightly higher than that of lattice beams manufactured using punched metal plate fasteners. The strength of wooden trusses manufactured in the laboratory ranged from nearly 20 N/mm2 to over 32 N/mm2. Thus, satisfactory primary values for further work were obtained.

Design of a snap connector to connect panel elements. The aim of this study was to design, manufacture and verify the tensile strength of a prototype snap connector to be used to connect panel elements. Firstly, analyses were conducted on solutions of commercially available designs for connectors invisible from the cabinet’s outside and those with minimized visibility. While searching for the best concept of connector design, three proposals were prepared, of which – after thorough analysis of design – one concept was selected. In the next step, the adopted solution was improved so that the connector met the previously formulated design requirements. In the course of further analyses, the causes and effects of failure were verified in order to limit or eliminate potential defects. In the next stage of the study, numerical calculations were conducted for the nut and the connector, concerning tensile strength, using the Autodesk Simulation Multiphysics program. After a prototype connector was manufactured, tensile strength tests were conducted on the connector using a strength testing machine. Experiments verified the correctness of the developed design in terms of geometry and the physico-mechanical properties of materials of individual elements, and resulted in possible changes proposed in the design of the final connector product.