So, the design phase is officially over. The final letter on design is in the mail... now I wait to see if Harold wants to try to make this corporation happen. The whole design was just an idea for Harold to work with, it lives or dies at his whim. If he gives it a go, and if the world wants to buy it, then my brothers and I would build it (if my brothers want to do that, I'm waiting for Harold's decision and then we get to see if the bros are onboard with it). It took me 11 months to communicate the whole design, during that time, I redesigned the entire bloody hoist and davit/crane. This is the final letter, that I just mailed...
March 25, 2019
Dear Harold, Mike, and Al,
Going to pick up details and design notes. Starting with the way to ship and pull out/extend the middle-mast. The middle-mast bolts to the top mast via a 2” thick x 10” bolt located 4” from the top, on the same axis as the corner plug. The top-mast has a 2” hole located 3” from its top, that the boom collar bolts through. So, for shipping, the middle-mast could bolt through that top-mast hole, except, there is only a 2” ID to the top-mast, so if a 2” thick bolt is used, there is nothing to snap hook to, so for shipping, we use a ½” thick bolt, washers, and a nut. The bolt head, washers, and nut fit into the corners of the bottom mast. The middle-mast will never be that far inside the bottom-mast that a man couldn’t easily reach in with a snap hook and catch the shipping bolt. (remember, the sample rig of an 11-foot wall? The middle-mast ships 9” inside the bottom-mast.) Once the middle mast is extended, the shipping bolt is removed.
I never did the cut-away view of the brake. I figure you guys got it. But there’s some cool things that happened with the new brake design and I never covered them. For one, I replaced the entire part outlay of transferring the braking load from the round brake pad/drum stop to the square mainframe with a single part that had the round and the square … and it did it via a 45-degree angle that turned that corner. That new octagonal brake design was genius, it even gave me an extra ¾” breathing room for my drop-down worm gear mooring. I’ll do the sides at 10” x 4”, so the corner spaces are 7” x 7” right triangles. There’s more…
The 3 vertical square tubes that separate the motor housing tube and brake from the battery compartment are now 3/8” thick x 19” tall. The octagonal brake slides on the center 10” of each side, so it is only 17” tall, hence, the opportunity arrives to make all 3 vertical square tubes the same height and take the same 1” thick mainframe bolt. That does some wonderful things for ventilation, first, it opens the outside compartment around the motor housing tube formed by the outside ½” thick frame plate and the two ¼” thick middle frame plates. It also opens a second ventilation shaft in the other inside corner of the battery compartment. The ¾” thick bolt plate covers that corner of the brake, so dust shouldn’t go directly into the ventilation flow of air, it is important to keep it clean of dust. This ventilation flow for the battery compartment is important because it provides flow through for the motor housing tube holes that feed the air cooling of the drum tube gears. It also keeps the batteries cooler. I think it may have saved the whole design. My whole game plan was to do the planetary gearing with a lower RPM motor feed (1400 RPM instead of 1725 RPM) and to use the big fans and unfiltered feed of air to keep the gears cool without a transmission oil bath. I don’t believe it has ever been done, this should be the first air-cooled planetary gears. My design kills all the speed in the first transfer to the gerbil gears; and the big fans are either blowing directly on that first transfer gearing or sucking from it.
The only alternative to air cooled planetary gears is to fill the entire drum tube with gear oil from end plate to end plate, something I didn’t want to do for multiple reasons; not the least of which was figuring out how to make a seal with the end plates; those are not bolted in, they are held in by the motor housing tubes, how the heck would I bolt those on? Then there’s the weight, and the weight ruins the spin balance of the gears, and also it is a maintenance nightmare. On top of all that, what could happen if the system fails? If gear oil seeps through the center shaft race and the fan blows it into the motor armature, killing the electrical down-brake, then the hoist runs away. So, the air-cooled planetary gears have to work or the whole design fails. This is the huge design leap that takes us from a drum hoist to a gear motor hoist.
On the davit truck, the mast-channel 3” thick plates bolt in from underneath the deck with 1” thick bolts, while the transmission box 2” thick plates bolt down through the deck with ¾” thick bolts. I use the same gearmotors, one side has the gear motor on the last tranny gear and it runs to the rear of the truck, while the other side has the gear motor on the 3rd tranny gear and it runs to the front of the truck. The gearmotors have to clear the mast-channel bolt heads, which they will, because they need plates against the underside of the deck to lower their shafts to the tranny gears, but we have to plan the location of the bolts to provide gaps for those mounting plates.
The design needs to educate the market, teach them what they need for the long-term maintenance of skyscrapers. To me, that’s the hardest nut to turn… I couldn’t do it, but if anyone could do it, Harold could. That doesn’t mean they will get on-board… those people hate spending money. But no one else is going to come up with this design. This is really their one opportunity to add this hoist and crane to their tool box. Harold should only attempt to give the planet this hoist if it is something he really, really wants to do. There’s also the education of the operators, especially the adaptation from rigging with a roof davit to rigging with a rolling crane. Sound like fun?
Lotsa love, Damian