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There would have been the problem you imagine, if the rope attachment were centered on the trolley directly above the zip line travel path. This would be the ideal location to align the pull force with the path of the trolley. Instead I attach on the left side of the trolley, while the intermediate zip line supports spaced down the bluff come down on the right and then under and up to support the cable. I don't show those supports but they are what you would see on a ski lift. I made those cable supports from old chainsaw bars and scrap metal . (left & right viewpoint: standing at the top of the bluff watch the trolley down below) Where I attach the pull rope is good enough that the trolley does not twist off, and thus the rope comes close to touching the zip line, but is always on the left side of it. The bucket is below the attach point so it never interferes.

No seal is perfect and the oil eventually finds its way out with the help of pressure and each time the spring is cycled. The worst is when people make the mistake of installing them upside down. I expect hydraulic seals in construction equipment die faster due to dust, dirt, wet, and scratches. Seals don't break, but they do wear, causing graceful degradation.

The calculation is correct since the "piston" in these is just for damping as in a similarly constructed . And to act as a end stop, that is what the o-ring is for, not sealing. Pressure is the same on both sides which gives the effective area of just the area of the rod.

Google "bicycle shock pump" or "bike shock pump". They are cheap and plentiful.

There ain’t no way you can get upto 350psi with a hand bike pump thats about 20 bars lol our high end Compressor at home only goes upto about 280psi

@@teammouse why not. its take time but its possible. Psi, bar, kpa is pressure of air. Its doesn't represent volume of air or whatever

@@ayn30 you know with a hand pump the higher the pressure gets the harder it gets to push the piston down at 20 bars it will be nearly impossible to compress even more

@@teammouse Hmm i think you dont understand how hydraulic and pneumatic work.

Everything dies, that's true. I bought the cap well used 15 years ago so the gas springs may be 30 years old in 2022. I have had to spend a few minutes charging them once since I posted the video but they still work. The truck itself and the deer it hit are no more, but the cap lives on as a bicycle shed.

Mystery machine #1 czcams.com/video/vRvJuHEm6UI/video.html Mystery machine #2 (better view) czcams.com/video/uuDO1ScCx2s/video.html I once imagined liquid nitrogen would be directly involved but the invisible hand of capitalism solved that. Holding a new small gas spring in my hand and looking down the top where the arm enters, and referring to machine #2 vid, there seems to be an integral valve just by virtue of the construction which is then especially sealed by the internal oil when you invert the spring to its default orientation. The tank PSI can be huge and a regulator can step it down to what is called for.

Thanks. Happy to help :) You will have to inject energy to raise your load but here is a thought: a counterweight that drops as your load rises and ultimately auto-dumps. If the counterweight is always less than the load you can pull it down using a tether attached to it, without much effort: that way your trolley won't accelerate out of control. Return#1: The counterweight can be hauled back up with a rope and pulley, where a hook on the end of the rope can anchor to something while you reload. Return#2: At the top, a helper fills the bucket with water until it happily sails back down to you. (never stand under the counterweight!!)

Air compressor tank fill valves I have ordered

It's worth a try. Bear in mind the force pushing the D=7mm diameter valve stem out is 400psi x [ 0.25 pi D*D / 25.4mm*25.4mm] = ~24lbs. Wear eye protection :) You want a snug threading job and the open question is how good the JBWeld epoxy bond to the outside of the metal tube is. With no extra effort you could add a few wraps of wire around the tube on either side of the valve to give something extra for the epoxy to grab. It does not have to look good, it just has to be good.

@@htpac yes it’s a lot of force… worth a try though.

Beamforming has long been public domain (not patentable) and my ideas regarding how to use it are now public domain, which was my intent. I thank you for broaching the idea of business inquiry but my days are full. An email or phone number in the comments is asking for trouble. If you have a question, I'll try to answer it.

@@htpac Thanks for reply, limited days are not an issue. Will really appreciate if you can drop me an email for details. See my info at czcams.com/channels/IfFIwgL60X6P79xkUUJHxg.htmlabout

Thanks for the "cool" :) I've zipped 3 truckloads so far, and maybe I'm done. I do briefly show the counterweight gear reducer. The idea is the main thing. What you might build depends on what you have handy but here are some thoughts. 1. I've reduced the reduction to 7X because available height allows that. The lighter the counterweight the better...lighter counterweight is easier on the counterweight cable and the system is more responsive overall and easier to tune so the bucket stops right where I am. 2. If you have grid power then electric motor rewind is a lazy option. The weight of gantry and empty bucket might be 20lb at most. 3. One pair of bicycle brake pads has zipped 3 truckloads yet shows minimal wear. Makes sense I guess...an adult cyclist is heavier than a bucket 'o rocks.

Plumbing soldering skill is a prerequisite. There are videos dedicated to that. Watch and do. Experience will bring you to the difference between a good solder joint and a "cold" one, which is the crucial thing you need to know. Get a feel for that and it is easy. Science: aspiring to be ignorant of a few basics is a blindfold for the mind. Don't trust me..."trust the science" :)

@@htpac So the point of the video was to show everyone how smart you are versus actually showing the work done in real time. Got it. I stand corrected. News flash smart guy anyone can post a video talking from a high level of understanding about a variety of subjects they are well versed in. For example I happen to be an network engineer. It wouldn't be hard for me to post a video that was intended to show how to redistribute EIGRP into OSPF Then go in depth from a high level of understanding about the protocols, never actually showing me configuring anything only then say Voila all done at the end! Yes it would make me look smart but wouldn't do much for helping the person watching the video actually accomplish the task at hand.

Schrader valves are so cool! Here's a video on how to install one onto a spray can to make it reusable. czcams.com/video/doLPFPeJ6JE/video.html

I lost my truck to a deer so I can't go and look at it, but I recall it was particularly hard to get at the shock sleeve and grip it no matter what and certainly no way to get a grinder or sawzall in there to cut it since it is inside coils. You are right that removing the wheel makes it a little easier, especially in the absence of ramps, but I think the problem remains fundamentally unchanged.

Cameron, you raise a good point about solder strength and there is such a thing as a “cold solder joint”. This is why the electrical code specifies Mar connectors and disallows soldering in house wiring: a good solder joint is better than mechanical contact, while a bad solder joint is worse. I could have taken a few extra minutes and brazed since that is not much more expensive than soldering. You can buy an oxy-acetylene tank that looks like a regular plumber's torch tank and it only costs double. Brazing torches are just rifled high flow propane torches. Tools pay the more you use them so the cost is negative. Note though, that the valve cylinder is 3/16th of an inch so the pressure on it is 0.0276 x 340psi = 9.4lb, not 340lb. Further, the Shraeder valve itself is the same as on the nitro charged shock on my dirt bike I had years ago - the valve itself is easily trust worthy at 400psi and beyond. Another way to think of it is when you put your finger in a dike to hold back the sea, it is boring and nothing more. The valve body is made of brass which is a copper alloy, so it solders fine, while brazing can melt it if you are not careful. Gas springs are made of cheap strong steel. You can tell when you have a good joint by the way solder wicks and flows - experience doing copper house plumbing will give you that feel. Someone said if we live beyond our reckless and stupid years (21+?) then we stand a chance of living to a healthy old age. It is a miracle I am alive. I can report that the springs are still working even though I lost my truck to a deer and the cap is now a woodshed on some land I have.

Such gratitude! But I understand you paid big $ for expert advice and you expect it to be professionally rendered.

My john deere damper is one of a kind and is $120 for an aftermarket. If this fixes my problem, I'll do a backflip.

@@mightymightymightyman199 how’d it go?

@@bruhh8908 Haven't fixed it yet. Still working on my cub cadet tank48 zero turn's hydros.

No seal is perfect, and no machining is perfect. You may lose a little gas with every cycle of operation, but I suspect failure becomes quick when the small squirt of oil inside from the factory finally is used up. That is a good reason to remember to ALWAYS install these with the cylinder up and the stem down so the oil seal can stay oiled inside.

Thanks for watching. Sorry, but my blunt answer (opinion) is no. Consider the parallel thoughput going on, the data rates required, and the computations you would need to do for the filtering/decimation. I have reverence for STM32 and noted long ago that the ST upper management mostly have engineering backgrounds, which is why it is a good company. If you can't find a way to beamform with an STM32 then the natural thought progression is to a fancy DSP and now it becomes an overly complicated programming problem on an expensive chip, when my design is trivial on an ASIC/FPGA. I knew a Chinese engineer who would pull out the epithet “cut the feet to fit the shoes” when we were trying to make existing hardware fit a problem it was never meant for :)

@@htpac Thanks so much for the super response. I have the obligation to use analog microphones to carry out beamforming. I could kindly ask you about the material to better understand the theory. Assuming we can digitize the output of analog mems with A / D and read the data with STM32, what remains is to program the microcontroller to introduce delays, right? I should fill arrays with the digital values of the microphones output and work on the sum by translating the cells. I thought so. I'm doing it wrong? I would really appreciate it. Good day

Thanks for the thx, I appreciate it. Also of possible interest is underwater beamforming, which is the natural follow on to basic sonar. It can see where there is no light or where water is muddy. I worked on a prototype back in 1986. Hope you get a good mark on your paper :)

Technically yes, since there would be no reactive oxygen. Interestingly, An apple farm near me keeps apples in cold storage for up to a year in CO2 filled rooms. I buy from them year round. Molecule size certainly illustrates itself in a helium filled rubber balloon so a bigger gas molecule has to be better, qualified by the size of the hole, which we don't know. Your good idea is definitely an improvement and here is how I would cheaply do it: fill a garbage bag with CO2 from a tank (fire extinguisher supplier 99%, or beer making 99.9%) and then charge the spring as I have done, but inside the bag. CO2 is heavier than air so no problem keeping it in the bag. Using car exhaust might be nasty but I'll never admit I think it would work fine :) I don't feel rust is primary or even secondary problem though. Internally the shaft is rubbed with oil every time the spring cycles, and the default resting position is compressed, protecting the internal shiny arm from the elements. A deer wrote my truck off but I'm keeping the cap as a small woodshed so I can run the gas shock experiment indefinitely.

A better way to avoid needing to solder valve is to get a dry ice and throw it in the cylinder and reassemble it quickly. One drawback is getting the right pressure. Too much dry ice might cause the strut to rupture/leak, too less, lifting force won't be strong enougj

It would work in principle but would have to be over built since you are trusting your life to it. You would want to add a safety brake in case the counterweight system failed, and you would want to add a safety hook in case your gondola gantry jumped off. The cable tension due to your body weight and that of your carrier would be massive, even though it reduces as your hill angle increases. Cable tension means a major anchor requirement. Easy to calculate. When you get to the bottom you would need to hitch your gondola so it does not fire back up and smash your counterweight system. You may be mindful of that and never have a problem, but it is not “idiot proof” for others. An alternate approach is some tracks and a 12V winch. While you are scheming you could always lay down a rope with knots and keep a pair of mechanics gloves handy: you still need leg power but it makes any slope easier:)

" the air will react to heat / cold more than the nitrogen ". how much? given that air is, you know, like 80% nitrogen.

@@cgoody3170 I make this assumption based on race car tire inflation when we use air the tire pressure increases as the tire heats up and the air expands. when we inflate the tire with nitrogen the heat from the tires does not affect the pressure in the tires resulting in a more consistent tire through out the race. I would assume the same would apply with struts. I could be wrong I been wrong plenty of times in my life so being wrong is no stranger to me. lol what are your thoughts?

Yep, you are wrong , NASCAR your talking extreme conditions to cause slight differences. A gas trunk spring filled with air or nitrogen in any weather condition would have negligible to nil difference.

@@madeleyinc then why would the manufacturer use nitrogen and NOT simply air? it would be much cheaper to pump air in them than to buy nitrogen. according to the strut manufacturers that I spoke to when doing the research for this video it was used for the very reason I stated. a car heating up in the hot sun can get pretty hot and that will increase the pressure more in an air filled strut verses a nitrogen filled strut. higher pressure means more likely to leak and lose pressure. of course this is all based off what my sources explained to me. it makes no real difference to me either way other than to provide accurate information obtained from the people who build and design these units.

@@daveknowshow The manufacturer use nitrogen is just for the safety reason. Compressed air(with Oxygen)+ oil = might explosion . You can use the google to translate the article. kknews.cc/news/xnn55no.html czcams.com/video/yPhcZxMWct0/video.html czcams.com/video/ptYNANsZXfQ/video.html

czcams.com/video/B_1bAnLqlMo/video.html The Saudi moving vehicle tire change trick needs a new twist - and you've hit on it

To a good approximation, PV=constant, so as you reduce the volume in your treadmill gas spring, the pressure goes up accordingly. Obviously if the housing volume is huge relative to the arm, then the pressure change between arm position extremes will be small. If the housing volume is small relative to the arm then you can get a much stiffer spring since the pressure change will be larger. The force on the sliding arm is proportional to the cross sectional area of it, since inside your spring, forces on the sides of the arm balance out, and only force on the end is not. Are the two, together, supporting 165lbs, or are each intended to handle that much independently? 165lbs is not far off the weight of a minivan hatch and I expect you need higher pressure than a 400 psi bike shock pump can supply. If your springs are junk you always experiment or just cut one apart for interest and see what it looks like inside.

Yea theyre junked off of 2 different treadmills. So one each is only used on the things is to assist when folding up the tread parts. But these things are ridiculously strong with the piston arm only a cm around and the strut assembly is about 1/2”. But extended they are about 2.5’ long tip to tip and half is piston rod and half is the housing. I really want to drill ahole and tap it with a schrader but i tell ya everytime i go to crank down on the press my giblets just start fighting and wont let me do it.. ive seen many drilled open with just a little psst like a coke can but my luck ill level my garage.. Theyre labeled 550n and other says 165lb. I weigh i know 210 and when i put all my weight on one or the other it just goes down so slowly. Maybe im not putting all my body in a linear motion and all but jeez.. You said minivan springs are around that weight though? I was wanting to decrease the pressure to add as hood or tailgate assists but figure the pressures are way too much as they sit. And worried about buckling at the little shaft like when your wife sits on it wrong real hard and ya make that sound.. ya know? Lol Gguhoooohshit! Ha! That’s funny right there..

@@Z-Ack You make me grin and also motivated me to add some example calculations in the video description. Your spring arms are 10mm diameter and from your description, the pressure is way up there - maybe 900psi. You have to have caution & respect and be thinking when dealing with that kind of pressure or hurt yourself. Assuming I had such a high pressure source, I would want to do an excellent job brazing or welding the valve because if it let go it could travel like an air rifle shot.

Thanks. If you can see and feel leaking oil then bad seals for sure, and I would not expect to salvage it. That would be a good strut to practice the fix on if you would value the practice. If it was the usual slow leak and you no longer get the lift you need, then your strut is worthless but a candidate for the fix.

@@htpac Great information, thank you. I'll try that when I can get a valve...

It is still working without another pump up. It took me less time to fix them than to drive to the store and back. I put in more oil than the minimal amount from the factory so maybe that was the main issue. Also, don't operate these upside down or they won't last long.

Maybe. Gas is going to always be leaking out at a certain rate. After years of existence, even a perfect strut will deflate. If this fix lasts a year between charges, it is worth it. The real question is, Why don't all struts come with valves?

You should at least try to hit the seals with acetone. It should cause the leak to stop.

Thank you Kevin. If you want a fun graphical math puzzle and to better visualize, pick N microphones and a target, then steer the beam in 2D to locations where you get an amplification of N, N-1, N-2, ... 1 for a particular frequency. Afterward, sweep the frequency to see how sharpness increases with frequency. By the way, I have found that scilab.org offers a compelling alternative to Matlab: I think it is better in some ways and it is also free.

Hey, get back into your little box.

Whyd you watch the video tho? If u were having issues with yours then why are you on youtube looking at videos rather than driving your ass to the money spending place paying for a new one. Meanwhile mr free shit right here will have his working and good to go again...

So educational if you just buy new one you will never learn his teaching incredible

I got here because I set out to buy new gas struts of equal quality to the gas struts that came as OEM on my leer camper. I think of it like this, do you buy new tires when your tire pressure is low? or do you air up your tires and continue to use them? I know struts are not tires but I think all struts should be refillable so they do not need to be thrown out when all they might need is a pressure recharge/refill. With the soldered in schrader valves I can do exactly that. I bet the cheap Chinese gas struts for sale on amazon that say they are compatible and will work on my application will leak down and go flat in 1 yr or less.

@@robert5 tyre nitrogen gas refill is install car all sturts or shock absorber? You have any video for nitrogen gas and oil filling shock absorber or sturt please send me link.

...Or a trailer pulled by snowmobile or barge pulled by boat, but the nearest public access officially forbids motorized vehicles and nobody local trusts the ice over the shallows down there (except one unfortunate who was found in the spring). Timer & motion all come back around to this direct route being fastest, as well as not bothering anyone. Rock to wheelbarrow, rock to zip, zip-pile to destination: same rock touched 3 times. I've ordered 3 more truck loads. Wish I had more time - you can never have enough:)