MMP126
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I can see no picture, so I am a little fuzzy on what you are trying to do. My take is that you are trying to keep a pipe vertical with some type of force acting down on it. And you want that force to be constant @ 5000N, but you need the for to be a steady 5000N directly down, even when there is some variation of force angle.
The use of spring here might work well. I have a picture in my head but I really cant come to a conclusion because i do not have enough info. A little more info and I might be able to help
Anyone else care to chime in?
8 months ago
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Niel Leon
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As stated by the other poster the picture still has not been posted along with your message.
I have used Constant force springs in a variety of applications. A 2000N or 450lb maximum constant force spring is something that is not standard and for a constant force spring would be very large. The largest stock constant force spring I was able to find in a quick review on the sites of some spring vendors I know only have springs with a maximum force of 45 lbs or 200N. This is one ten the force you are looking for.
For constant force in a stationary application weights are just the easiest least expensive option. If you use cables and directing pulleys you can have the force be applied in just about any direction you desire.
You should also consider using an hydraulic or pneumatic cylinder to generate the force. Hydraulic cylinders can easily generate the forces you are looking for safely.
Niel
8 months ago
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Gjerm
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Thanks. I have tried so many times to attach a jpeg and gif picture with sice beneath 50 kB, but it doesn't work properly. I will try to make the picture in your heads: I have a 1 m steel pipe in a vertical direction. There is a rope connected to it to create a streatching force. The rope goes trough a pulley 20 cm above the end of the pipe. This pulley changes the direction of the rope to horisontal. The pulley is removeable in horisontal direction. This will make different angels of the rope connected to the pipe. The rope goes trough one more pulley, making the direction of the rope vertically. the rope streches to the ground, where there may be constant force springs and a power supply.
But are the force of the springs steaddy? I know you can make them paralell to make them stronger. But for 2000N I need 10 of the 200N springs!!
8 months ago
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Gjerm
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This is a nice page with nice pictures
http://www.lesjoforsab.com/standard-fjadrar/112-118_sv_id991.pdf
8 months ago
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Niel Leon
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Is your little Avatar picture the system you are talking about?
If so you could use multiple springs as shown in the catalog to get the force you are looking for.
Yes, as long as you use them properly you can expect them to provide the rated force though their rated stroke and number of cycles. Most companies provide information on variation in that force.
Unfortunately I only read English so the catalog is only a little bit of help.
The big advantage of constant force springs is that they do provide a constant force over long distances. What is the total working length for your system?
Niel
8 months ago
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Gjerm
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Yess, thats a simple picture of it.
It is about 15 cm. On Friday I found something called gas springs which can hold constant force. But these only work in pressure. I think I can use these if I find a smart way to put them.
8 months ago
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Niel Leon
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Yes, a gas spring would work, as would a conventional pneumatic cylinder. Gas springs are great if you have to have the force be uniform across a distance for a specific application and the system is going cycle a large number of times.
The pneumatic cylinder would allow you to change the force if necessary without changing the mechanism.
It all depends on what you are trying to do. A 2000N air spring is a big air spring.
Niel
8 months ago
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