[Yahya (OP)]

I have recently invented this new hand saw :
the double jaw saw is a hand saw with two blades , an ordinary saw needs from the person cutting both wood and metal to press it while cutting, the double jaw saw gives the pressure for the hand saw using strong springs instead of doing it manually there are two springs fixed inside to push both jaws towards each other , a person should first use the disks to open the lower blade and the upper blade , when the jaws are wide open , a metal or wood is put between the jaws you then let go of the springs so the jaws are pressed to each other while cutting the jaws approach each other digging deep into the metal , this hand saw make it easier to cut wood or metal it decreases the energy needed by hand to cut wood or metal , in addition it is simple just as the ordinary hand saw.

[Colin2B]

Interesting.
This would have the advantage of cutting from both sides, preventing breakout of the wood fibres on the bottom edge.
Have you made a prototype?
I can see a couple of disadvantages you will need to work on:
- Cost will be high compared to an ordinary saw.
- Friction will be higher. Usually a handsaw is held at an angle rather than parallel to the surface and this reduces the effort required.
Good luck

[RD]

... this hand saw make it easier to cut wood or metal it decreases the energy needed by hand to cut wood or metal ...

It could decrease the time taken to cut the wood , but it cannot decrease the amount of energy needed to cut through the wood, see ... https://en.wikipedia.org/wiki/First_law_of_thermodynamics

The thickness and length of the wood it could cut would be restricted by that design , ( and require more force & precision than usual ).

Unless there is a niche application for that design  I wouldn't go into the  Dragon's den with that product idea.

[Yahya (OP)]

I have not made a prototype yet , the high friction is possible , but I think that will make the process fast , although more force may be required , but using this tool will help in holding tight the metal so you will be able to exert much force easily

[RD]

...  although more force may be required ...

More force must be required if you double the number of blades.

As a general-purpose saw it's doomed to failure. Could it accommodate a 10cm diameter tree-branch ? ,  could it cut excess from a 80cm-wide door ?.

Unless it has some niche-application, then you're flogging a dead horse.

[Tim the Plumber]

If you make a prototype it may work better than you expect. I urge you to do this.

Whilst it will never be a general saw replacing all saws it does not need to. There are plenty of applications where the cut needs to be straight and true without any odd mismatches when you butt up the piece to the next one. I think it may work for this but without a working example you are lost.

Don't worry too much about loss of intelectual property as yet. There will be loads of details to work out on this project. But when you get anywhere near a working tool you must not post in this fashion. Look at the intelectual property laws. Anything in the public domain is not protectable. Talking it through with your wife will kill it. Anybody you talk to about it needs to have signed a none-disclosure agreement. Or your project is dead befor it is born.

I would be happy to sign a reasonable agreement and be your practicle sounding board if you like. PM me.

[Yahya (OP)]

Could it accommodate a 10cm diameter tree-branch ? ,  could it cut excess from a 80cm-wide door ?.

it couldn't , but it will be good for smaller sizes .

[Yahya (OP)]

Don't worry too much about loss of intelectual property as yet.

I already filed a patent application.

[Tim the Plumber]

Don't worry too much about loss of intelectual property as yet.

I already filed a patent application.

Good but expect the thing to change a lot as you actually build it.

Good luck.

[Colin2B]

Could it accommodate a 10cm diameter tree-branch ? ,  could it cut excess from a 80cm-wide door ?.

it couldn't , but it will be good for smaller sizes .

I think you would be best to look for a niche in the precision cutting market.
As Tim says, it's not going to replace the general purpose hand saw.

[Yahya (OP)]

I think you would be best to look for a niche in the precision cutting market.

what does that mean ?

[chiralSPO]

Unfortunately it looks like someone else has already beaten you to the double hammer, but I propose a double screwdriver to go with your double saw (both pictured in attachment)...

[Yahya (OP)]

I like the hammer , unless it hits my hand with one head while I pound the nail with the other head []

[Colin2B]

..... unless it hits my hand with one head while I pound the nail with the other head []

I assumed that was part of the design brief! []

[Yahya (OP)]

this invention worked very fine as a hacksaw , I made a simple prototype  , with the same components  and design ,and I was able to cut a 10mm solid iron bar in a minute. with little effort.a video shows the process

www.youtube.com/watch?v=HL0TP3ZnM60