Determination of coefficient of friction for a novel bed mechanism

Abstract

In all the mechanical systems it is important to know the amount of friction and the actual torque required to drive the system. In this context, this manuscript discusses a simple, practical approach for estimating the coefficient of friction and the operating torque in a mechanism used for a novel bed with commode. The commode is brought in useable position by a mechanism which moves the bed platform down and then horizontally away from the commode opening and vice versa. This article presents the design of platform mechanism, estimation of operating torque using a specially designed setup and calculation of the coefficient of friction using basic mechanics. The results show that the coefficient of friction in the mechanism decreases with increase in the load on it. A mean value of coefficient of friction of 0.2396 is estimated from the trials. Calculating the torque to operate the mechanism using the mean value of friction results in some error in the torque values and the error is within 10% of the actual values. Thus, the mean coefficient of friction can be used conveniently for estimating the torque in this mechanism. This friction and torque estimation will be useful for determination of crank sizes for manual turning of screw and motor rating for automatic operation of the mechanism. RECEIVED