Hmmm but isn't that what you are supposed to do???

Put an add in the media that you are looking for a broken / failed jack.

Analyse it and find the mistakes and take it from there.

Sir,

I want to design new jack not repair on failure jack.

So plz help me.

If there is any book related to it then plz send me.

With Regards,

Saurabh Maggu

you are a student. right?

You have some homework to do. right?

Instead of designing from the start I gave you an option to take a bad design and improve on that.

In analysing you would learn a lot, and improving will set the grey stuff in motion and prepare you for future useful work.

What more do you want?

Note if you can find a jack also find out under what conditions it failed.

I don't mean to be critical in any mean-spirited way, but you have had two excellent answers. If you want to do design engineering, both those are quite good paths. It is highly unlikely that you will find a "cook-book" approach for a scissors jack design. The design steps are actually rather simple, but it takes a lot of education/experience to know which to apply and the best way to get that is to try to do a design, either completely from scratch or by fixing an old design.

Many of us will gladly help you, but you must be willing to accept some guidance.

CR4 isn't a homework help site. Besides, if we do your homework for you, what have you really learned?