Design and Validation of a Device to Aid in Extension Ladder Setup

Joseph C. Musto, Adam C. Resnick, Michael C. Fricke

Abstract


The problem of ladder base slippage is a leading cause of workplace injuries and causes a number of annual deaths.  Research has shown that ladder users tend to set up extension ladders at an angle between 66° and 69° above horizontal, which is much shallower than the specified standard of 75.5°. This results in an increase in the friction required at the base of the ladder to support the weight of the ladder and its user, and leads to an increased likelood of a slideout accident.  To counteract the problem of ladder base slipping, a device was developed to aid the user in achieving a proper setup angle.  The device uses a mechanical switch to wired to LEDs that provide the user feedback on setup angle.  The device was tested in a laboratory environment, and was shown to positively impact the ability of the user to erect the ladder at a proper angle.


Full Text:

PDF

References


Barnett, R., & Liber, T. (2004). Sloped surfaces – ladder slide out. Triodyne Safety Brief, 25(1), 1-6.

Campbell, A., & Pagano, C. (2014). The effects of instructions on potential slide-out failures during portable extension ladder postioning. Accident Analysis and Prevention, 67, 30-39.

Chang, W.-R., Chien-Chi, C., & Matz. S. (2005). Available friction of ladder shoes and slip potenal for climbing on a straight ladder. Ergonomics, 48(9), 1169-1182.

Engineer's Handbook (2006). Reference tables -- coefficient of friction. http://www.engineershandbook.com/Tables/frictioncoefficients.htm. [Accessed 10 November 2013].

Simeonov, P., Hsiao, H., Powers, J., & Kau, T.Y. (2012). Factors affecting extension ladder angular positioning. Human Factors: The Journal of the Human Factors and Ergonomics Society, 54(3), 334-345.

Simeonov, P., Hsiao, H., Powers, J., Kim, I.J., Kau, T.-Y., & Weaver, D., (2013). Research to improve extention ladder angular positioning. Applied Ergonomics, 44, 496-502.

Wilson, J. (1990). A generalized gnalysis of the ladder slippage problem. Proceedings of the The American Society of Mechanical Engineers Winter Annual Meeting, Dallas, Texas, 1990.




PRINT ISSN No.: 2180-1053
E ISSN No.: 2289-8123