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.
Design and Testing of Low Cost Chair with Round Mortise and Tenon Joints
ZACAL JAROSLAV, DOSTAL PETR, SUSTR MICHAL, BARBOUTIS IOANNIS A. 2016. Design and Testing of Low Cost Chair with Round Mortise and Tenon Joints. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 64(2): 567–572. The present paper focuses on construction of school seats for developing countries from locally available resources using the local industry and low-end technology. Aim of the work is experimental assessment of mechanical properties of joints fl exion in angular plane. Furthermore work considers assessment of joint fi rmness and comparison between various joint types. Paper encloses the review of various joint manufacturing designs (tenon and mortise), which were proposed for its suitable mechanical properties and simplicity of manufacturing. Designated joint type is easiest form of joint construction and technologically feasible for chair manufacturing. The joints were constructed from fi r wood. Further the work introduces design of simple seat construction made from massive wood material manufactured by low-end technology with regards to achieving the due specifi cations. The task of this work is to design the viable manufacturing process of seats and chairs from raw wood and scrap material. Essential part of work is also manufacturing of seat prototype and simplifi ed model of proposed mortise and tenon drill.
ASSESSING AGE AND GENDER DIFFERENCES IN PERCEIVED RISK AND FEAR OF CRIME
Much of the research on fear of crime indicates that women and older persons are highly afraid of crime. These findings, especially older persons' fear of crime, are widely communicated in the scientific and popular media. This study examines age and gender differences in perceived risk and fear of crime. The data are from telephone interviews of 320 randomly selected residents in a southeastern metropolitan area of the United States. The relationships of age and gender to fear of crime are compared using a National Crime Survey (NCS) measure of fear of crime and 11 alternative indicators of fear of specific offenses. Women reported signifcantly greater perceived risk and fear of crime than men regardless of how fear of crime was measured and older adults reported the greatest fear of crime when the NCS measure was used. but not when the alternative individual measures of fear of crime were used. A LISREL model with latent constructs for fear of personal crime and fear of property crime also indicates that older adults do not have higher levels of fear of crime. In short, the extent of fear in the everyday lives of most older persons has been overestimated in many previous studies because of measurement problems.