Imploding Kubota Cab Windows?

[jaceyvineyards]

Has anyone experienced a imploding or exploding cab window on a Kubota Tractor? This happened recently to one of our tractors, and we are pretty confident that no objects hit the window, as the window imploded outwards from the cab and cutting an employee.

 

[oosik]

Difficult to believe that a tractor cab would be that air tight. Closing the main door compresses inside air to the extent that a window blew out. OR, sitting in the sun increases inside air pressure and blows out a window. Must have been an improperly secured/sealed window to start with. Hope the employee is OK now.

BTW - welcome to TBN.

 

[jaceyvineyards]

Thank you, yes the employee is okay. The tractor had factory installed window, the original. Just very bizarre.

 

[XMS]

Glad your guy is OK.

Check the cab for stress areas, specifically roof sections. If the cab came out of shape, it could cause a pop like that.

The chance that air pressure did this is about one in a trillion. It would require a violent expansion event (explosion) that created more volume than the many openings in the cab would normally allow to expel, and then that volume would have to be sufficient to blow out a window on something designed to be driven hard. That kind of rapid volume expansion would show up as damage elsewhere, too, and I could not imagine a source that wouldn't be real obvious (welding gas canister depressurization, etc.).

But, if the glazing got scratched, and pressure was applied the right (wrong) way due to an impact or deformation of the frame, it would shatter.

I have not seen this in a tractor, but I've seen it in other vehicles and in buildings.

EDIT: one of the times I saw something similar it was new windows that had been etched by water. It was odd, but when we unloaded them from the trucks we had to leave them outside under cover to acclimate. For some reason I never quite understood, bringing them straight into the warehouse after unloading would damage (etch) a few of them from condensation. Invariably some would shatter. The really odd thing was these were windows designed for external use (building windows) and I never heard of them having a problem in freezing winters or searing heat, after install. Their major enemy appeared to be baseballs in school yards.

 

[dusty3030]

Tempered glass when it goes can go either direction so it would be near impossible to say if something small hit it or not based on which way the glass went. Positive pressure from the AC or heat going inside and an object hit from the outside the bulk of the glass could very well blow outside.
In a previous life I was a maintenance person primarily worked on refrigeration but also had the task or repairing vending machines as a part of the job. I have seen it all when it comes to tempered glass breaking.
It could have been an unseen defect in the glass, could have been in a "bind", something could have hit it. If a defect in the glass or a bind just the right temp and jolt and it let loose.
Glad person is OK.

 

[TripleR]

We have never ha it happen on any of or Kubotas, but had two on our Case CX80, both left side door and we never did figure it out.

 

[texasjohn]

I've experienced, twice, a busted cab glass. Both cases I was driving and did something stupid...in a hurry both times...busted one door, one back glass. Am surprised that anyone got cut. In my cases, I was in driver seat both times. Glass shattered into lots of small shards. No cuts either time. I don't recommend this experience...expensive!! Don't get in a hurry and all is OK.

 

[jaceyvineyards]

Thank you, I will investigate all of these ideas.

 

[jaceyvineyards]

Yes, I am finding more and more incidents with Case tractors.

 

[bumperm]

dusty3030 has it right.

I was a police evidence tech (Oakland CA), it's interesting to note that when a small, high speed projectile impact glass, that often the majority of the broken glass will be on the impact side. A BB impacting normal glass will eject a small cone of glass on the inside, but with tempered glass, it'll just crumble, and finding the BB is next to impossible.

Another possibility is that the glass was installed improperly and with an edge able to contact metal (a bead from welding etc etc). This could cause stress to make the window shatter upon closing or?

bumper