# Compound Slingshot Patent



## boyntonstu (Jul 16, 2010)

I discovered this while searching the US Patents.

It give me a new way to add power to the elastic.

I would do it differently,.

Imagine a trigger between two sets of elastic bands.

I can visualize a drop down or swing down device.

The front set is pulled towards the fork.

The rear set and the pouch is pulled from the trigger to the rear trigger.

Link both triggers and shoot.

The front set could be 100 pounds and set by dead lifting then like cocking a crossbow.

The pouch is drawn by hand.

I could also imagine pulling the front trigger and having all that force pulling the pouch out of your fingers.

This is fascinating.


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## ZDP-189 (Mar 14, 2010)

I wonder why we don't find them in Wal-mart?


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## Tex-Shooter (Dec 17, 2009)

Here is another one that has always looked interesting to me. I don't know why these have not shown up at Wal-Mart.







- Tex-Shooter
http://www.google.com/patents/about?id=6_k-AAAAEBAJ&dq=1,153,415


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## JoergS (Dec 17, 2009)

Most of these are based on the idea to use string that draws out parts that are connected to rubber.

I have tested extensively with these things and stopped all work.

1. The mechanics take power (and there is not much to begin with)
2. The accuracy suffers greatly from unavoidable tolerances
3. The string is dead weight that gets accelerated very much, which is dangerous, lashes out like a whip * BEWARE *

Every time I tried such mechanics, it was a failure. Mechanics are OK for a lock/trigger, for a draw winch and so on - but the bands and pouch have to run freely.

Jörg


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## boyntonstu (Jul 16, 2010)

JoergS said:


> Most of these are based on the idea to use string that draws out parts that are connected to rubber.
> 
> I have tested extensively with these things and stopped all work.
> 
> ...


Jorg,

I agree with you about the problems with strings and pulleys.

I am thinking of something else.

Instead of my green and red TB tubes connected to each other and drawn as a single band, imagine two sets of TB rubber (tubes or bands) that are joined/spliced at a trigger point but which are independently drawn.










Place the trigger and pull point between the red and the green.

If you cocked the heavier bands with your feet, you could easily go over 100 pounds,

The result would be a 100 pound slingshot drawing and accelerating your regular slingshot; say 35 pounds.

I would imagine it would be extremely powerful and fast.

.


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## ZDP-189 (Mar 14, 2010)

Without some principle of mechanical advantage, the limit of the speed of a bandset is the speed at which it is capable of shooting without a projectile. All a heavier draw would achieve is the ability to fire heavy projectiles without much reduction in velocity. That in itself is a worthy motivation, if you plan to shoot big river stones up into the trees.


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## boyntonstu (Jul 16, 2010)

ZDP-189 said:


> Without some principle of mechanical advantage, the limit of the speed of a bandset is the speed at which it is capable of shooting without a projectile. All a heavier draw would achieve is the ability to fire heavy projectiles without much reduction in velocity. That in itself is a worthy motivation, if you plan to shoot big river stones up into the trees.


Maybe yes, maybe no.

The way I look at it, the projectile for the heavy set is the lighter set and its projectile.

Imagine the heavy set accelerating a fork to 100 fps.

I calculate that 100 pounds of force over 6 inches would accelerate a 0.5 pound fork to 100 fps.

The 100 fps fork would be pulling the lighter bands and it would contribute 100 fps to its speed.

If you shot a 200 fps slingshot forward from a car going 88 fps which is exactly 60 MPH, the projectile would be traveling at 288 fps.


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## NaturalFork (Jan 21, 2010)

What if a recurve limb were attached at the bottom (look at the illustration) and the energy came from the limb and not rubber?


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## boyntonstu (Jul 16, 2010)

RecurveMaster said:


> What if a recurve limb were attached at the bottom (look at the illustration) and the energy came from the limb and not rubber?


Yes, a limb could provide the power.

What would be the advantage of using limb power instead of rubber power?


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## Brooklyn00003 (Feb 28, 2010)

boyntonstu said:


> What if a recurve limb were attached at the bottom (look at the illustration) and the energy came from the limb and not rubber?


Yes, a limb could provide the power.

What would be the advantage of using limb power instead of rubber power?
[/quote]

Hello

I dont know about these things, but what if you put bands on a crossbow?

The crosbows limbs will accelerate as normal plus you have the rubber bands on it .

Then there will be acceleration from the limbs and the rubber.


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## boyntonstu (Jul 16, 2010)

That is the goal, to add speeds.

A crossbow trigger point would be the fork position from which to draw the slingshot.


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## Tex-Shooter (Dec 17, 2009)

One of the problems that I see with the one that I posted is it would probably lose its vacuum over time so there would need to be a port to reset it. I don’t know if the recoil pad is needed either as I don't know if it would pull a compete vacuum. I did some tooling with a vacuum cylinder concept and it requires some high tech cylinder seals. It did however rebound almost instantly. I think that the handle cylinder would have to be about 1 1/2 inches. I know for a fact that I don't have the ability to make a prototype of such a complicated device, but it is an interesting concept. I wonder if a prototype was ever made. -- Tex-Shooter


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