2011年4月11日月曜日

One month has passed


Today is 11th April.
One month has passed since the tragic earthquake occurred.....

Aftershock of 3.11 M9.0 is still continue.
I am not sure when it is calm down....

So, Reactors of nuclear power plant is still keep stable.
We want to say to our government and TEPCO, "We want to know correct information of plant condition and radiation level!!" and "Who is the Leader??"

I have to do possible my self day by day.




2011年4月5日火曜日

Chain broken


Hi,

Last Sunday, it was little bit cold. Was it returned winter??
I did ride fixed gear bike 50km. I had a trouble that my bike chain link was broken!!

I was riding at 20km from my home. Suddenly my crank did no reaction force!!
I did stop the bike immediately and confirm, chain derailed from rear cog. I think it is strange because single gear bike chain line is straight!! It has not push force of side direction.

I putted chain on cog again and re-started. I hear some noise from chain, confirm again during riding.....a point of chain was bending!! I stopped again and check carefully.

Oh my gooooood!! Chain link was broken!!
See Photo!!






However, I was lucky because broken link plate only inside!! Still connected!!
I had no chain connection pin and chain cutting tool.....I decided to return to home with broken chain.

I had to ride carefully especially in starting situation. I kick the ground hardly on starting!!
And very careful acceleration.

Finally I returned to home safely, but take about 1.5 hours for 20km. (normally less than one hour)

Checked broken link plate with scope. It is metal fatigue due to tensil stress cycle after small crack. (I found start point of crack and shell mark of fatigue sign)

My estimation of process of broken is follows;
1. 1st small crack was occurred by chain connect and remove because I had bend to inside link plate for connect and remove.
2. It has tensile stress in forward and backward pedaling (it's fixed gear), 1st small crack should be propergated.
3. Inside link plate was broken. I could not find. However, I heard some noise from somewhere before few minutes of derailed chain.
4. Finally, then accelerated bike, broken link was in front of rear cog, outside link plate was pulled by big pedaling force and bending to outside direction, chain derailed!

Why chain link crack occurred?
In my opinion is this chain's connect link specification is not so good for many time connect and remove.
I wrote I had to bend to inside link for connect and remove chain. I did two or three times.
Link plate has large strain at sometime, perhaps over the yield point of metal material or small crack was occurred.....


I purchased new chain is not necessary bend for connect and remove.

I have to check other critical points.
Brake wire, brake pad and other.....

Keep fun and take care!!!

Bye.