E MCH 13 Design Project: Swing Arm Lamp
10 February 1999
Problem
Design a dual swing arm lamp. Key specifications:
- Dimensions to accommodate those of a typical American sofa. Height to be 40 in minimum.
- Load to accommodate the 50th percentile range for weight of U.S. children who have just turned three years old .
- All internal wiring shall be concealed within the lamp .
- Safety factors are 1.5 for material yielding and 2.2 for buckling.
- Each swing arm will be 4.5 in long minimum.
- Materials to have an attractive appearance with surface finish 32 μ in AA minimum.
Design objective
The design objective is low cost, but not at a loss in elegance or appearance and finish. Costs are to be estimated using nominal retail prices.
Special concerns
- Consider that the lamp may be carried by either arm or the post.
- Weakness of the arm-to-hinge joints.
- Safety in general is a major concern. The lamp should be stable under normal use.
References
Hibbeler, R.C. (1997) Mechanics of Materials, 3rd ed., Prentice Hall, Englewood Cliffs.
Roark, Raymond J. and W. C. Young (1975) Formulas for Stress and Strain, McGraw-Hill Book Co., New York, Table 37. Formulas of stress concentration for elastic stress.
Salvendy, Gavriel (1997) Handbook of Human Factors and Ergonomics, John Wiley & Sons, Inc., New York.
Pheasant, Stephen (1996) Bodyspace: anthropometry, ergonomics and the design of work, 2nd ed., Taylor & Francis, London.
This material is based upon work supported by the National Science Foundation under Grant No. 0633602. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).
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