Emergency Kill Switch

Description

There are times when it seems important to be able to cut off the Mule quickly. One of those times is when I'm loading the Mule in the back of the truck as I walk it up the ramp. Another is when I am driving from the walking position in the mountains. There is very little flat ground so the mule is going sideways along the ridge or actually climbing up fairly steep grades, often with a sizable load.

This project is to describe how I implemented an emergency kill switch to cut off the engine in the possibility something goes wrong while operating in these precarious conditions. This solution allows a lot of flexibility in the positioning of the switch in relation to the mount. It is just one possibility but hopefully it will spark other implementations.

ONE VERY IMPORTANT NOTE: This device should always be tested after installation and before you may need it!

Design Considerations

The switch has to be stable, operable at almost any angle and RELIABLE! I finally thought about the emergency kill switches used on boats, jet skis, ATV's etc. This solved the reliable part, Now on to the mounting. I wanted to be able to remove the switch when using the Mule under normal conditions but it had to be stable. After poking around in my "junk" ( Fred Sanford would be proud. ), I found a couple different kinds of gun mounts for ATVs which I felt could be reused as temporary mounting brackets when necessary.

Materials

NOTE: BOLD text are hyperlinks which were valid at posting.

1 1/4" x 1/8" x 4 1/2" Aluminum flat stock
2 - 4-40 x 3/8" Flat head machine screws
3/8" x 16 x 1 1/4"" Machine screw ( usually comes with the Grip mount )
3/8" Flat washer
3/8" Split lock washer
Emergency Kill Switch ( Universal Kill Switch SeaDog Line - See Picture 1 )
2 - Right Angle Wire Connectors ( Heat Shrink Flag Terminal Right Angle Wire Connector - See Picture 2. )
Wire Conector ( Connector Set Polarized SeaDog Line Or SeaDog 2 Pin Polarized Electrical Connector )
16 or 18 Gage Wire
Heat Shrink Tubing

1/2"
3/8"
1/4" ( Roll - See Picture 3. )
1/8"

2 - Posi-tap Connectors, 12-18 Gauge Wire ( See Picture 4. )
Coleman Fin Grip mount. ( one of the following links below )
OR
Make something similar.

SINGLE FIN GRIP PRO HANDLEBAR RACKS ( Option A - See Picture 5 )

2 - 1/4" Wing nuts
2 - 1/4" Split lock washers
1/4" x 1-1/8" x 2" U-Bolt ( The supplied U-Bolt is usually too narrow )

FIN GRIP PRO RACK SINGLE ( Option B - See Picture 6 )

4 - 1/4" Wing nuts
4 - 1/4" Split lock washers
4 - 1/4" x 2" Carriage bolts
3/8" x 16 Nylon lock nut ( usually comes with the Grip mount )

Tools

Hacksaw or Band-saw
Drill
5/8" Drill Bit
3/8" Drill Bit
4-40 Tap w/#43 bit
Some way to bend the aluminum flat stock, i.e. Vise, Brake, etc.
Wire Cutters and Strippers
Soldering gun, solder and flux
Heat gun or Torch

Steps

Refer to Figure A for steps 1 thru 7 below:

Cut the Aluminum bar to length.
Use a scribe and mark all the layout lines.
Center punch the 4 drill points.
Drill the 4 holes.
Tap the 2 small holes for the 4-40 screws.
Chamfer drill the 2 small holes so the 4-40 screws are flush with the surface.
Bend the bar at the indicated mark 90 degrees.
Loosely mount the switch in the 5/8" hole in the bracket.
Determine where you want to mount the switch and attach the mount.
Orient the bracket in the desired position and screw the two 4-40 screws into the bracket.
Screw the 3/8" screw with flat and lock washers through the bracket into the mount and tighten.
Prepare the plug wire that will connect to the original kill switch. ( Refer to pictures 9 and 10 )
Under the Mule, make the connections from the plug wire to the Magneto wires using Posi-tap Connectors. ( See Figure B for wiring diagram and Picture 4 for Posi-Tap Connector. )
Determine how long the wire needs to be from the switch to the just finished connector and cut to length.
Connect the mating plug to the the wires. Offset the connections by ~ 1". I use a Western Union splice, solder and cover with heat shrink tubing. ( Refer to pictures 9 and 10 )
Slide the 1/4" heat shrink tube the length of the wire, also slide the 3/8" and 1/2" lengths of heat shrink tubing on the wire.
Solder or crimp the 90 degree wire connector to the opposite end of the wires.
Arrange all the heat shrink tubing and complete the Switch Wiring Harness. ( See Picture 11. )
Route the wire and align the switch terminals so the flag terminals line up and tighten the switch nut.
Push the flag terminals onto the M terminals of the switch and plug the 2 halves of the connector together.
Make sure the Clip with the lanyard is attached to the switch.
Start the mule, pull on the lanyard until the clip comes off the switch and the Mule should stop running.