Лесотехнически Университет

Summary

A comparative analysis between the destructive bending moments of end and T-shape corner joints of details from solid chestnut wood (Castanea sativa Mill.) with cross section of 50 x 25 mm has been done.

In this study has been found that the types of joints and the area of their contact surface have considerably influence on their strength characteristics. The T-shape corner joints have in average about 20 % higher destructive bending moment compare to the end corner joints. The non-dismountable mortise and tenon joints are destroyed by average of 80 % higher bending moment compare to the dismountable joints. Dowel joints have two times lower bending moment compare to the mortise and tenon joints and from 3 to 24 % higher bending moment compare to the dismountable joints. 

Summary

The results from the research on the tightness characteristics of the middle angle combinations details from massive chestnut wood with a cross section of 50 x 25 mm used in the construction of seating furniture have been given.

It has been found, that according to the point of the damaging bending moment, the unassembling middle angle combinations are arranged in the following falling order: through conductive oval knot and tenon type A ; through an unconductive oval knot and tenon type A ; through conductive oval knot and tenon type B ; through oval knot and tenon type B ; through two dowels 10 mm ; through oval plated knot and tenon.

According to the point of the damaging bending moment, the assembling middle angle combinations are arranged in the following falling order: through two one elements joints type „Confirmat“; through two screws for timber; through two joints with screw and cross dowel, Swedish type.

The results from the research are recommended to be used in the measurement of the furniture for sitting.

Summary

A comparative analysis has been done on the experimentally found destructive bending moments in the loading of bending of the most commonly used end and T – shape corner joints of details from solid chestnut wood with two types of cross section of the details – 50 x 25mm and 50 x 30mm.

It has been found, that the type of joints and the thickness of the joining details have a definite impact on their destructive bending moments.

With the increase of the thickness of the details from 25 to 30 mm (with 20 %), the destructive bending moments in the loading of bending of the end glued and dismountable corner joints increase respectively with around 28 % and with 33 %, and of the T – shape corner joints – with around 23 % and around 17 %.

It is recommended that the found out destructive bending moments in the loading of bending and the most commonly used end and T – shape corner joints of details from solid chestnut timber with cross section 50 x 25mm and 50 x 30 mm be taken into consideration in the choice of the type of joints in the sitting furniture construction.

Summary

In this work, the ultimate tensile strength of some T-shape corner joints of structural elements of solid beech wood with cross section 50 x 25 mm used in the construction of seating furniture is investigated. It has been found that with reference to the value of ultimate tensile strength, the glued T-shape corner joints are arranged in the following descending series: with stub mortise and tenon; with wedged mortise and tenon; with stub mortise and tenon and dowel, with dowels. With reference to the value of the ultimate tensile strength the dismountable end corner joints are arranged in the following descending series: with two connectors with screw and cross dowel; with two one-piece connectors “Confirmat”. It is recommended that the results from this research can be utilized when calculating the dimensions of seating furniture.