E MCH 13 Design Project: Ladder Gym Set
4 September 1997

Problem

Design a Horizontal Ladder Gym Set per the concept sketch shown. Key specifications:

  • Dimensions to accommodate the 50th percentile range of U.S. children, ten years old.
  • Load to accommodate the 90th percentile range for weight of U.S. children, ten years old.
  • Height of the horizontal ladder to be 1 inch greater than the vertical reach of U.S. children, ten years old.
  • Spacing of bars for steps and grips must meet the dimensional specifications.
  • Lengths of rings, trapeze and swings should be adjustable.
  • Safety factors are 1.3 for material yielding and 2.2 for buckling.
  • For ladders and top bars, metal is preferred, but plastic materials will be accepted if grip dimensions do not exceed specifications. Materials for these members are not to be mixed; specify metal for all or plastic for all.
  • Deflections of ladders and top bars must not exceed 1/4 inch under normal full load.
  • The set must ship disassembled and be able to be assembled using basic household tools.

Design objective

The design objective is low cost, but not at a loss in appearance. (Costs are to be estimated using nominal retail prices.)

Special concerns

  • Joints made by commercially available connectors must be adequate.
  • Safety in general is a major concern. The Set should be stable under normal use.

Report

The design will be done in U.S. Customary Units. Follow the "Design Project Report Format for E Mch 013 with Design".

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.

Web site: http://www.componentplaygrounds.com/, viewed 18 September 1999.

 

 



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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