GopherHawk arming tool (updated 9/5/20 - released) by cgfan

Last crawled date: 3 years, 3 months ago

9/5/20 update: Success w/functional test of full-sized print! Released design out of "work in progress" status.


9/5/20 update: Did a first-time full print of the design and found that laying down on the printbed it is extremely difficult to hold the circular cross-section of the design, as gravity will inevitably cause it to flatten under its own weight. While this may be different for different setups or FDM media, it takes very little deformation to use up all of the clearances built into the design, even for prints which may appear visually fine.
My conclusion is that this design benefits greatly by printing it standing up. So I added an updated design which brings down the height of the tool by 0.2", lowering its maximum working depth form 7.8" down to 7.6".
The older design was sized to just fit my Sapphire Pro's printbed when laying on its side and oriented along its diagonal. This new shorter design now just fits the maximum Z-height of my printer.


9/4/20 update: Tested key portions of design: Printed full-sized but partial sections of the design to test key portions. Printed the upper collar portion for fit of its internal channels and all looks well. Also printed the highest stress portion of the design, right around the area where the waist flare is found, and it held up beautifully after multiple simulated deployments of the trap.
Now printing for final testing of the full design.


Updated 9/2/20: Found clearance issue between the GopherHawk's tab and the inner shell. Also added a waist flare to resist tension around the circumference and increased the base flare to better channel the stresses to the ground.

Introduction
The GopherHawk is a very popular and effective tool at catching gophers in a no-touch manner. Generally no conventional digging is involved to set the trap, only the use of a dibbler to create a hole to set the trap.
The one aspect which makes the trap tricky is its arming. To arm, one first inserts the trap in the hole until it hits the bottom. One must then pull up against a very heavy spring the outerbody, all the while keeping the center plunger absolutely still above the hole. Specifically one must not push down on this plunger, as any push on it will deform or damage a rather delicate wire trap as it's being deployed.
Certainly it is most unnatural to keep a plunger at a fixed height above the ground while using one's strength to retract the outer body up, all the while avoiding any downward movement.
Usage
This tool allows one to simply extert a downward force on the GopherHawk's plunger in order to deploy the trap. To use one simply slides the tool onto the GopherHawk, guiding a tab found on the side of the GopherHawk down a channel cut into the wall of the tool.
When it bottoms out consider the tool and GopherHawk as one. Simply insert into the hole and push gently down until it rests in the bottom of the hole.
Note that this tool will decrease the depth of hole that can be used, and should not be used past where the top brim contacts the ground. As designed it will be limited to holes roughly 7.6" deep or less (or with the older version for holes roughly 7.8" deep or less).
Arming
Now it's time to deploy the trap. Firmly press down on the plunger - yes, right where it warns "DON'T PUSH DOWN". Within reasonable limits this is safe to do as the pushing force on the plunger will be redirected through the body of the tool. At the very bottom of the tool is a foot flare that rests on the bottom of the hole, safely shunting the force to the ground and away from the deploying snare.
Within this foot flare is enough protective room to safely deploy the wire snare of the trap w/o interference. However if the ground is particularly soft some ingress of the ground into the deploying snare can be expected - too much of this will eventually cause damage to the snare, so exercise caution as even with this tool it does have its limits.
Exposing trap to tunnel
Although the trap is now deployed, it is still not exposed to the tunnel. While keeping the GopherHawk still, simply rotate the tool CCW until it stops (about 120 degrees), then pull up on the tool until it stops again (about 2-1/4 inches). Think of this as an "L" shaped rook's move. This "L" shaped move will expose the trap to the tunnel and allow it to expand, which in turn will prevent the tool from falling back down the hole.
Note that while armed the tool will stay in the ground with the GopherHawk until you have made your catch. The tool will not obstruct the GopherHawks indicator, so the yellow band will appear as normal once the trap has been triggered.
After the catch
To remove simply pull up on the GopherHawk, which should also pull up the tool. Though unlikely, if the tool detaches from the GopherHawk simply remove from the ground by pulling on its collar.
Rearming
To rearm, first ensure that the tool is lowered on the GopherHawk, about 2-1/4" max. This may have naturally happened, or even partially, when you pulled the GopherHawk out of the hole. When it hits the stop, rotate the tool CW (about 120 degrees looking down at the GopherHawk) untili it hits another stop.
At this point it is ready to be rearmed as before, or stored as-is. If one wishes to store it disassembled, simply slide the GopherHawl from the tool and the tool should release.
https://www.youtube.com/watch?v=ZBZA2wtYP3Qhttps://www.youtube.com/watch?v=IUqlOPQEU5Q