The next generation in DPV technology - Logic Dive Gear Genesis 600/1240

[betti154]

There is a groove in the tube and a groove in the tailcone that line up with each other when assembled. The square cross sectional strips are inserted into the aligned grooves, filling them both, and act just like a square key in a shaft/pulley connection to prevent movement. Internal pressure would put the strip into an axial shear loading situation and would theoretically require over 10,000 lbs to shear that length of strip.

Hi Jon,

Very nice machine! It'll be cool to see the benchmark results.

With regard to the strip locking mechanism, if it's not a trade secret would you mind point me to a diagram or similar of this? I'm very interested in implementing something like this for a DIY canister light solution I'm working on.

Kind Regards,
Damien Siviero
Damien Siviero Photography

 

[Ben_ca]

Some really innovative scooter design elements. Look forward to the TBM numbers. Congrats!

+1

What he said

 

[Jon Nellis]

With regard to the strip locking mechanism, if it's not a trade secret would you mind point me to a diagram or similar of this? I'm very interested in implementing something like this for a DIY canister light solution I'm working on.

I used it on a canister light I put together a few years ago. I don't know of any graphic to show it better than a shaft and pulley with a keyway, but instead of running axially between the two parts to take torque, it is oriented circumferentially between the two parts to resist axial movement. The strip acts as the key.

 

[Akimbo]

… No stainless clamps to connect the body to the tail - Streamlines the flow into the nozzle and avoids galvanic corrosion due to dissimilar metals
View attachment 99837
…

I don’t I understand. What is the significance of the wire hanging out forward of the Kort nozzle and how does it relate to the caption?

Are there any dynamic penetrations/controls?

 

[betti154]

I used it on a canister light I put together a few years ago. I don't know of any graphic to show it better than a shaft and pulley with a keyway, but instead of running axially between the two parts to take torque, it is oriented circumferentially between the two parts to resist axial movement. The strip acts as the key.

Thanks, got it. I sat down with a pencil and it became clear.

 

[Jon Nellis]

I don’t I understand. What is the significance of the wire hanging out forward of the Kort nozzle and how does it relate to the caption?

Are there any dynamic penetrations/controls?

Hi Akimbo,

It is not a wire, it is a plastic strip that acts as a key to hold the body to the tail. Its the discussion of the post previous to yours.

As for the dynamic penetrations, there are exactly zero, none, nada, zip! Not even on the variable speed lever. If that is you in the hard hat (and I'm guessing it is since you can identify a real Kort nozzle) you can appreciate the lack of rotating seals better than most.

Best Regards,
Jon

 

[Akimbo]

…It is not a wire, it is a plastic strip that acts as a key to hold the body to the tail. Its the discussion of the post previous to yours…

Let’s see if I understand. I imagine you have a piston seal O-ring on the housing and something like another groove on the wet-side, half in the female and half in the male side of the housing. Then two angled holes are provided for a flexible plastic rod.

If this is correct, is there a problem getting the housing open in the event a lower pressure develops inside the housing due to temperature or altitude? For that matter, is it difficult to assemble due to air trapped in the housing as the piston seal is inserted?

… If that is you in the hard hat (and I'm guessing it is since you can identify a real Kort nozzle) you can appreciate the lack of rotating seals better than most…

Definitely, way too many long days replacing failed motors. In Helium environments the motor housings had magnetic drive couplings and the housing would be TIG welded shut. The only O-ring was on the electrical penetrator and occasionally they would leak.

The only reliable dynamic motor seals I have ever seen on ROVs and submersibles were pressurized oil-filled drives. They were heavy and messy (leaked oil everywhere) but weren’t depth limited, implosion hazards, and never failed as long as the oil reservoir stayed full.

 

[Jon Nellis]

Let’s see if I understand. I imagine you have a piston seal O-ring on the housing and something like another groove on the wet-side, half in the female and half in the male side of the housing. Then two angled holes are provided for a flexible plastic rod.

You got it, but the only correction is there are double seals.

If this is correct, is there a problem getting the housing open in the event a lower pressure develops inside the housing due to temperature or altitude? For that matter, is it difficult to assemble due to air trapped in the housing as the piston seal is inserted?

Atmospheric changes don't create enough pressure differential to prevent opening or closing, beside the purpose of the external recharge port is to avoid having to open the housing in the first place. Changes in altitude do create enough pressure differential to prevent opening which is why there is a -4 MS port next to the recharge connector (also used for pressure/vacuum testing). Even if you were to say, take it to Tahoe for a weekend of diving and closed it up at sea level before driving up the hill, there's really still no reason to open it when you get there.

It will take a while to break everyone's knee jerk reaction to having to open the body to recharge the batteries.

The only reliable dynamic motor seals I have ever seen on ROVs and submersibles were pressurized oil-filled drives. They were heavy and messy (leaked oil everywhere) but weren’t depth limited, implosion hazards, and never failed as long as the oil reservoir stayed full.

I'm quite familiar with them, I used to design 4000m rated work class ROVs. Think of the Genesis scooters as a work class DPVs.

Cheers,
Jon

 

[vjanelle]

Does logic dive gear have a website? A quick google search showed nothing.

 

[Jon Nellis]

Does logic dive gear have a website? A quick google search showed nothing.

There is not a website at the moment. There is a possibility that the scooters will be marketed through a larger, international gear manufacturer who for now will remain nameless. Talks are underway and as soon as a decision is made, it will either go up on their website, or a Logic Dive Gear website will appear.

Regardless, the first production run will be available before Christmas.

Thanks for the interest,
Jon