Rescue instructor Shawn Haynes sent me a box of bearings and a picture of Richard Delaney’s friction reducing micro-rollers wanting one built for evaluation during rope rescue training. Quick to build and turned out pretty nice. 8 ¾” overall length, 3 ½” wide and 2” high. Total weight is 1 pound 14 ounces. Sending it out today so he can put it to the test this weekend during some training to see if we need to modify anything.
I would be concerned about the device flexing because of it using only 2 rods across. If you run into this problem and the device is designed to be only used on 1 side. I would consider placing at least 1 flush mounted rod in the center on the bottom edge for stability ( rods would form a V shape) or 2 flush mounted rods on the bottom almost below the other 2.
No issues with the way it is built. The design comes from one Delaney built and has used extensively doing 2-person load rescues in industrial settings, so you can throw this over a stairwell, elevator entrance, etc. and the haul ropes have almost no friction due to the edge.
@Jeff Randall That’s a cool little gadget I worked on robotic arm designs a few years back that used a pivot pin design similarly to that and it was a problem we kept having... Imagine If you held both end pins in your hand and twisted opposite directions, that was the force we kept fighting with. JIK you run into a problem you have a possible solution
Looks sweet Jeff! Would a contraption like this, benefit at all from the addition of thrust bearings?
I don't think so. I actually thoughts about putting thrust bearings on the end of each axle, but after assembling it and getting everything tightened down, it really doesn't need them. There's a washer between the race and outside frame, as well as a washer between every bearing, so each bearing turns as an independent unit. Not to mention there's no real side to side weight on this once it's working.