Gravity/Grappling Hook

This model is based on a gift my wife gave to me several years ago - a stainless steel gravity/grappling hook. )If you are interested you can find the stainless steel version on amazon here: https://a.co/d/5YDCH3A )

Gravity hooks can be used in a lot of situations and can pick up things incredibly well - from keys to coins, if you drop it, this can pick it up!

Although I have used this on almost every single camping trip since and it has a permanent spot in my hiking bag, there are two main problems:

1. Its HEAVY! This is good for when I have used it to haul heavy stuff but that is a very rare use in my experience.
2. There isn't a good place to store the separate cross hook that makes it a grappling hook.

Because of these two issues, I have reverse engineered it and made it 3d printable! Now both problems have been resolved 

1. It is super light weight. This makes it perfect for the small load use I normally use it for (such as hanging stuff from a tree or dropping a line down a cliff to pick up my fallen keys)
2. The cross hook fits perfectly around the #8 nuts used to hold the whole thing together, and when the rubber band is placed around the lower arms it holds the cross hook in place which means I will never have to go digging to the bottom of my bag to find it again.

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Some Assembly is required along with some additional hardware:

Printed Parts: 

3x Lower Arm

3x Upper Arm

1x Cross Hook

Hardware:

3x #8-0.5" screws and nuts

1x Screw Pin Anchor Shackle (I found these on amazon: https://a.co/d/d2lQfPU )

1x Rubber Band or O-Ring (optional, for use only with the Cross Hook to hold it in place.)

Assembly Instructions: 

Starting with the three “Upper Arms”, place them as shown in the photo below and put a #8 screw through the top hole of all three pieces. Make sure the arms are alternating such that the two outside arms are in the opposite direction from the third.

Now, place 2 “lower arms” on either side of the middle “upper arm” and put a #8 screw through the two "lower arms" and one "upper arm". Make sure the notch in the “lower arms” are closest to the “upper arms” and point outward as shown below. 

Next, place the remaining “lower arm” in between the two “upper arms” and place the #8 screw through the 3 arms, again with the notch as shown in the picture below.

Lastly, place the shackle through the bottom hole of all 3 “lower arms". 

The gravity hook is now complete. 

Gravity Hook → Grappling Hook:

To convert the gravity hook to a grappling hook, simply insert the “cross hook”  piece in the jaws of the gravity hook, and the tips of the "upper arms" will go through the rectangular hole in the “cross hook”, thereby anchoring the “cross hook” in place as long as the gravity hook is closed. It can be kept closed by use of a rubber band around the notches in the “lower arms”. Alternatively, I just used an O-ring I found laying around as you can see in the picture below.

Cross Hook Storage:

To store the “cross hook”, slightly open the gravity hook until the nuts on the backside line up with the square holes in the “cross hook” as shown in the image below. Once they are lined up, use the rubber band or O-ring to keep pressure on the “cross hook”.

Assembly Tips:

The holes for the bolts should be loose in order to allow the gravity hook to move freely. Depending on your print settings the holes may print too tight and need to be opened up with a drill bit. 

Be careful that you don't overtighten the bolts as this will also restrict the movement of the gravity hook.

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There you have it! I hope this gravity/grappling hook will serve you as well as it has served me. I would love to see what uses you find for this neat little camping gadget!!

Enjoy and always let me know if you like the print or have any questions!!

-Ricky