Bending Capacity of Middle Joints of Upholstered Furniture Frames
This study evaluates the edgewise bending moment capacity of the four most frequently used middle joints in the upholstered furniture frames. The research included the following joints: Mortise and Tenon, double Dowel, Corner Blocks and double Gusset Plates, designed in the form of middle joints and made of beech and poplar solid wood. The test results indicated that regarding the edgewise bending force, the strongest middle joint was the double dowel joint made of beech wood (1896.9 N), while the respective joint made of poplar marked quite a low value of bending force (937.2 N). The strength of wooden corner blocks was proved to be quite powerful, made either of beech wood, poplar wood or the combination of the two wood species (beech: 1881.8 N, poplar: 1237.6 N, beech-poplar: 1783.6 N). The gusset plate joint made of beech resulted in weaker values (1378.2 N), compared to the dowel and corner block joints made of beech, whereas the same joint made of poplar demonstrated very satisfying values of edgewise bending force (1471.8 N). Finally, the mortise and tenon joint appeared to have the lowest strength, both in the case of beech (1306 N) and poplar (634 N). The highest coeffi cient of elasticity (CE) derived from double gusset plate joint, made of beech. All the joints showed good elasticity, except the mortise and tenon joint made of poplar, as well as, the dowel joint made of poplar, which recorded the lowest elasticity values of all. Generally, beech wood resulted in stronger and more elastic joints compared to poplar.
Moment capacity of traditional and alternative T-type end-to-side-grain furniture joints
The bending moment capacity of traditional and alternative T-type end-to-side-grain joints constructed of Oriental beech (Fagus orientalis Lipsky), European oak (Quercus borealis Lipsky), and Scotch pine (Pinus sylvestris Lipsky) were investigated. Two-pin dowel and mortise-and-tenon joints assembled with polyvinyl acetate adhesive were considered as traditional adhesive-based joints, and minifix plus dowel and screw joints were considered alternative non-adhesive-based joints. Experimental results indicated traditional adhesive-based mortise-and-tenon joints yielded the highest bending moment capacity among the four types of tested joints, and that minifix plus dowel joints had the lowest bending moment capacity. Screw joints could produce higher bending moment capacities than traditional glued dowel joints. The bending moment capacity of minifix plus dowel joints was less sensitive to wood species change than mortise-and-tenon joints, dowel joints, and screw joints.
Mechanical Behavior of Joint Connectors on Furniture (Frame Construction) Design
In this research, mechanical behavior of traditional and alternative joints which are used on construction design of furniture frames have been investigated. Those members which are taken into the frames construction as tension, bending and shear strength members with dowel, mor-tise- tenon joints with adhesive and two types of furniture connectros and a combination of both of them are five types of joints have been tested totaly under static load. Results indicate that the alternative joints which are provided flexible connections are more succesful than traditional joints which are provided rijit connections.