Development of Hardness Test Device for Determination of Comfort Parameters in Pillows and Experimental Study of Hardness Measurement

People spend a third of their lives asleep. A good night's sleep is a key to waking up pain-free, while providing an excellent opportunity to rest. Pillows are indispensable objects for a comfortable sleep. Sleeping position and personal preferences influence on the type of pillow a person need. However, there is no mutual language for the perception of comfort. This study focuses on the experimental study of the hardness measurement process to establish an objective method for evaluating pillow hardness and to examine the relationship between sensory evaluation and compression properties of pillows. In order to determine the comfort and pillow hardness parameters, studies on various fields and products were examined. A machine that measures and defines the compression amount of the pillow and the height data obtained by applying a certain force to the entire surface of the pillow has been designed. Pillows with different properties and weights were tested and the height values after applying the force were processed within the data obtained from the machine. By determining the limit and mean values, the pillows were categorized as soft, medium-soft, medium, medium-hard and hard. As a consequence of this study, through the developed hardness measurement method, product classifications were made and the user's feeling on pillow hardness was observed.