Research and Presumption on the Failures, the Causes and the Reliability of the Small Grain Binder

Abstract

The binders, which have been developed in Japan of late, heve much diffused in the last few years. We investigated the impaired parts of 31 binders, and intended to clear up the causes of the failures by the Weibull probability diagram. By the use of the diagram, the parts which were needed to change the design, the force of the urgency, the mean time to failure of the parts and the root causes of the troubles could be predicted.
The survey up to Jan. 1970 showed that the following parts got out of order, (A) binding clutch arm, (B) driving chain for binding section, (C) knotter bill, (D) pick-up tine, (E) cutter blade, (F) throwing arm, (G) cord cutting knife, (H) universal joints for straw shifting shaft and (I) spring pins for rotary paddles to shift straw.
The parts E, A, B, C, D, F and I wore-out and failed. The mean times to failure became shorter in their order. To insure longer lives of these parts, it would be neccessary to change the design and the material and to retrain operators of the binder.
The parts G and H failed because of random failures, and they did not seem to wear-out at that time.
The parts C, D and H showed initial failures. To eliminate these failures, quality controls, running tests in the producing stage, and the operational training for users would be effective.
Were the failures only in the parts A, B, C and D, it could be said that the reliability of the binder would fall to 9 percent in the third year, and 50 percent of binders would fail in all parts A, B, C, F and H before the binders would have harvested 720 hours or 55 hectares.
The use of Weibull probability diagram for analyzing failures of binders was effective in that it analyzed failures in the relationship between strength of the parts and users' actual circumstnces of operation.