National Institute of Occupational Safety and Health, Japan
Impact Strength of Wire Rope (The 3rd Report)
SH-1963-1-1
Eiji AKIYAMA, Taiji KONDO and Teizo HAKAMAZUKA
: We tested wire ropes under some conditions and obtained next results.
(1) In a corroded wire rope, the drop rate of the shock breakage load is nearly equivalent to the static one. But the shock breakage energy drops remarkably in comparison with the load.
(2) In a deformed wire rope, the shock breakage load does not drop so much as the static load.
(3) About the eyesplice of a wire rope, the maximum shock breakage load measured in the fixed side is higher the static one. But the elongation to breakage by shock is very small.
Prevention of Accidents Caused by Falling Articles
SH-1963-1-2
Jiro SAITO, Kazuo UCHIYAMA and Kinichi KINOSHITA
: Accidents have been caused one abter another by falling from high places at job sites of building works.
So, we built the experimental tower for making various articles fall and tested the intensity of wire nets, canvases and the materials of asagao that are set at the job sites for the purpose of preventing accidents by falling articles. Before the experiment we had inquired into the sort and weight of the falling articles that had caused 1812 accidents during the 35th - 36th year of Showa and from the results of the inquirement, the following were the experimental articles we had chosen the mass of steel ( 7.5 kg ), of concrete ( 2.4 kg ) and of timber ( 7.8 kg ); steel globes ( 1.7 kg - 7.1 kg ), steel pipes ( 2.73 kg - 9.45 kg ), steel bars ( 4.5 kg - 7.5 kg ), and tools ( 300 g - 600 g ).
As the conclusion of the experiment, the following facts became evident.
1. Preventing wire nets outside the buildings under construction at the job sites;
a) It is suitable to use wire nets of over 20# wire, and the nets of 13 mm meshes.
b) It must wrap the other by the 10 cm - 15 cm breadth and at the wrapped part it must be bound alternately "Chidori" at intervals of 50 cm - 60 cm.
2. Level preventing wire nets in the job sites;
It must be set every two floor by the ways mentioned in the article 1.
3. Preventing canvas;
As strong a canvas of vynilon or trayon as a wire net must be used.
4. Asagao;
It must keep the angle between the level 20~30 degrees and need to be used thicker timber plates than 1.5 cm.
Influences of Temperature and Pressure on the Inflammability Limits of Methane
SH-1963-1-3
N.Taguchi, H.TURUMI and M.NAITO
: Influences of temperature and pressure to the upper inflammability limit of methane are studied.
Experiments to establish the upper limit in the temperature range from room temperature to 400 °C and pressure range from atmospheric to 10 atm, show that the upper limit is raised with rise of temperature and pressure, and is 51 per cent by volume at maximum temperature with maximum pressure.
On the other hand, influences of added inert gas on the inflammability range of methane under elevated temperature and pressure are also studied.
The results show that the minimum volume of inert gas to added for non-inflammabilitizing methane and air mixtures at 350 °C with 10 atm, is about two times at normal condition.
