DIY Star Trek doorway

[HeyBub]

With step-by-step and videos

[The Daring Dufas]

I installed and repaired many automatic doors at supermarkets, hospitals and other institutions. The Star Trek doors I worked on that were once ubiquitous, were manufactures by Stanley and used long brass pneumatic cylinders that had to be rebuilt on a regular basis. The rubber disk check valves also had to be rebuilt often. Long ago, the air doors were superseded by 90 volt DC drive linear actuators or rubber belt drive systems. I haven't come across an old Stanley air door in many years. Most of the latest technological advances have been to the operating and safety sensors. Automatic doors are big business for lawyers.

TDD

[aemeijers]

I glanced at the web page, but with my slow connection, didn't try to watch the videos. Did he address what happens in a power failure? I realize the tank would hold enough air for several hours to open the door, but how does he trigger it when the sensor has no juice, and most importantly, does it fail open, like if house is on fire?

[harry]

Regular automatic doors can be pushed open if they fail. But hey, why not get totally immersed in Hollywood! There was person over here converted his living room into an Enterprise flight deck. You see. We got nutters too.

[DerbyDad03]

re: "Regular automatic doors can be pushed open if they fail"

There is a short video and an extended one. In the extended video he shows how he can turn off the air, the power and vent the system via a control panel *inside* the room.

After he did that he said "...and now I can open the doors manually." One could infer from that statement that the doors can not be opened manually with the system powered up and charged.

So the question remains: If he is out in the hallway, can he indeed open the door if the system malfunctions?

If simply pushing the doors will open them, then the lockout code on the hallway panel is pretty much useless.

He didn't say anything about fail-safes, but that doesn't mean they aren't build in, thus the question remains about the operation of the system during a malfunction or an emergency.

[The Daring Dufas]

All of the commercial automatic doors I installed and serviced had a breakout feature. I should note that it applies to sliding doors. You may see a little red sticker on the door that instructs you to push on the door in an emergency. The door will pop loose and swing open. The commercial doors have all sorts of proximity sensors and safety features to protect even the dumbest of humans but people still get hurt. It's a constant battle against the dumb asses of the world. :-)

TDD

[aemeijers]

That is what prompted my original question. I get the impression the kid was finishing high school when he did the project originally, and I gotta give him kudos for his shade-tree engineering, especially at such a young age. But guys that age are immortal, and now that he is out of the house, can his mother (or the guest she parks in what is now presumably a guest bedroom) deal with a complicated escape procedure? The fact that he 'upgraded' the compressor on his last trip home tells me the setup isn't quite as anvil-reliable as he implied.

Yes, it is cute. but I have doubts it would pass muster with building code/fire dept, or their insurance carrier.

[Jules Richardson]

If there's a fire, don't you just escape by teleporting to somewhere else?

[krw]

Nah, the transporter controls are always the first to burn, right after the red-shirt get eaten by the alien life form.

[Robert Green]

My dad did forensic engineering when he retired from the Navy. Automatic doors really do injure people, especially the older doors without enough sensors. Elderly people who move slowly are the most likely to get slapped in the butt and knocked down by a door that "thought" that enough time had elapsed for a person to clear the "swingway." That's why they've added mat sensors, radar sensors, photocells and ultrasonics to many modern automatic doors. Someone's grandma got knocked down. Repeatedly.

It's not just the dumb asses - it's the slow movers, too.

Multiple sensors became necessary because often times, maintenance on the doors is deferred until an accident occurs. My dad continually came across systems where a single sensor (out of 4) was left functioning and one sensor is just not enough to figure out whether grandma has actually cleared the door. As you're probably aware, many of the doors are made to be quite powerful since they have to close against the significant air pressure that can occur on windy days. That results in some pretty serious injuries to elders with fragile bones.

But I can guarantee you from the grisly pictures he often brought home, that automatic door accidents are a walk in the park compared to elevator accidents where door closes on someone's arm and the car suddenly drops. The worst I saw was when some kids got into the elevator room on the roof in public housing in Baltimore and got caught up and shredded in the cable/pulley system. There was another case at Syracuse U. where a repairman cut off all the safety interlocks on a elevator WITHOUT placing "out of order" signs on each floor as required while he worked on the system.

There are enough fatal elevator accidents that occur each year to sustain several law firms that do almost exclusively elevator litigation. A large portion of elevator mishaps occur because of a failure of the door safety lock mechanisms. The doors "catch" people and the car drops and, well, you can imagine the rest. The bigger cars just cut people in two while smaller cars sort of rip them apart. Often, the head is pulled right off the neck.

-- Bobby G.

[aemeijers]

tv8$teo$ [e-mail]...

One of the benefits of growing up in construction- much like growing up on a farm- you learn at an early age that industrial machines can kill you and not even notice, much less care. And yes, motorized doors should be considered industrial machines.

-- aem sends, on Google pretty much till new year's.....

[The Daring Dufas]

Back in the mid 1980's Besam automatic doors had a new infrared safety proximity sensors to detect the presence of people in the doorway. It was installed on the swinging doors. The sliders used motion detectors and one or more photocell type safety beams and current sensing for the drive motor. If the current draw was too great when the door was closing, it would reverse and open up. The swinging doors were power open and spring close with the infrared safety bar on either side of the door. The bar is around 3-4 inches wide and as long as the door is wide. Dark red plastic strips covered two rows of emitters and a center row of detectors. If there was a reflection of infrared light anywhere along the strip, it would signal the door stop. The only problem item for the sensors to detect was fur coats, it seems fur absorbs infrared radiation. Oh yea, I just remembered, Besam came out with an infrared safety bar that looked down from the top cover of the sliding doors looking for a reflection of infrared light. I saw a woman get hit by one of the sliders when she slipped up the side of the door instead of walking straight through. Chrome guide rails are added to some door systems to prevent people from coming in from the side. People will find a way to get hurt no matter what you do. :-)

TDD

[Robert Green]

That's true, but the constant feedback from lawsuits has made a lot of products much safer than their first design iteration. Tjat's especially true of elevators, automatic doors and cars. From seatbelts to soft dashboards to flush door hardware on cars - all came about as a result of the litigation/design cycle. There's a societal benefit in making things safer although Darwinists might disagree. The NEC is only a series of rules but it's saved countless lives by making the electricity in a house safer to use. I owe my well being to various safety devices like air bags, seat belts, fuses, saw guards, goggles and more. I am sure I am not the only one here that owes a debt to safety engineering.

Here in the DC area, the Metro officials can't keep their escalators running. The most recent case was when the braking system failed (oil on the mechanism, they say) and people were accelerated toward the bottom by a runaway escalator. This was the train system that killed quite a few people last year when a track control system failed. While Metro officials were intent on blaming the train operator, persistent discovery requests from lawyers for the dead revealed that it was a long standing problem and came about partly from mixing parts from several manufacturers.

I've been to a lot of similar trials, and once the stakes get large enough, companies actually do redesign their products to be safer when it turns out to be more expensive not to. Yes, some people find the safety features to be an annoying intrusion but it's clear that things like dead man switches on lawn mowers and various other safety interlocks do save lives and prevent serious injuries.

It's a process of stepwise refinement. If the IR can be "fooled" by fur coats (worn by rich, litigious patrons, I assume) then the next generation of sensors will be designed to detect them - after the trial and the big payout. It's not evil, greedy trial lawyers looking for a buck (well, maybe). It's the way that feedback gets to the manufacturers to encourage them to do a better job. Or, in cases like the little tool that shaved the ridges off your fingernails, to go out of business when your product has harmed the requisite number of customers. (-: Anyone know if "Slip and Slide" is still in business? Last I heard they had a number of adult customers paralyzed from the neck down because adults don't quite flex like little kids.

-- Bobby G.

[The Daring Dufas]

I my neck of the woods, many deaths occur to young intoxicated men who's last word follow a strikingly similar theme which is "Hey y'all, watch this!".

I never ceases to be amazed at how the simple use of common sense prevents most accidents. When I work on electrical equipment, I work on it as though it is energized even if the power is disconnected and I don't trust that anyone will leave a safety switch alone no matter how big a warning sign I put on it instructing people not to touch it. Yes, I know all about lock out kits. I've even seen an idiot break the lock off a safety switch, the lock was bright red and the moron couldn't understand why I was yelling at him.

I'm an aggressive defensive driver and I drive like everyone is out to get me. I remember a little thing from drivers education classes back in high school where the instructor in a film said to play the game of "what if" while driving. "What if this fellow swaps lanes without signaling?" "What if that driver runs that stop sign?" it soon becomes second nature and you do it on a subconscious level. I'll be driving along and I'll suddenly slow down or change lanes, quite often something dangerous happens and I would have been in the middle of it. It saved me one day years ago when I suddenly changed lanes without thinking about it and out of the corner of my eye, I saw an Ingersoll Rand towed air compressor flipping end over end in the next lane as it passed me. That damn thing weighed more than the car I was driving.

TDD

[Robert Green]

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aem sends, on Google pretty much till new year's.....

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Damn, you're marked man posting from Google. I shouldn't be seen posting with you! Oddly enough, I grew up with an engineer dad who fixed our cars, radios and TV's (tube days - even had a tester) and had a healthy respect for things mechanical. It was a horse what learned me. (-: As a city kid, I never saw that one coming.

I was watching a film from the 40's the other night that had closeups of the cars of that era. Sharp-edged steel dashboards, coach doors, ornate doorhandles, massive chrome bumpers and a steel rod steering wheel pointed right at the chest.

Should you be able to buy a car with no internal safety features? Ideally, in a free enterprise system, I suppose and only if we were able to tolerate people lying dying by the side of the road. I mean people ride donorcycles, and the safest one of those is probably as safe as a completely safety gutted, seatbelt-less, air bag-free car.

Someday, the needs of rich old men for healthy body parts will see those silly safety laws reversed.

-- Bobby G.