Abstract
The dispersion of tightening force in plastics bolt is discussed, for the two methods of tightening which are usually applied to steel bolt, from the view-point of obtaining the higher precision of tightening force in the bolt. The joints with plastics bolt used here are classified into two types from the standpoint of different combination of materials which take part in sliding friction, that is, TYPE 1 composed of plastics-to-plastics and TYPE 2 plastics-to-steel. Both methods of tightening are also conducted by two ways of manual and power drive and they are compared each other. As the results, main conclusions obtained on the dispersion of tightening force are as follows : (1) The tightening by the turn-of-nut method can reduce the dispersion as compared with the calibrated wrench method. (2) In the turn-of-nut method, lower snugging torque results in higher precision in tightening force. (3) In TYPE 1, the dispersion in manual drive is larger than that in power drive, in case of the calibrated wrench method, while the difference of the dispersion between manual and power drive is negligible in case of the turn-of-nut method. (4) In TYPE 2, the difference of the dispersion between manual and power drive is negligible in both methods of tightening.
