Hello everyone,
Below the sketch of the current kinematics (pretty much)
First observation: the useful stroke of the cylinder is not used in full -> loss of efficiency
Second observation: the lever arm is too weak because of the position of the jack, too close to the horizontal.
Request help for my project black 600
Here is the optimization of the positioning of the cylinder, using the entire stroke and seeking to have the largest possible initial lever arm.
It is still a bit fair to raise the mast alone and you have to check the intermediate positions because the lever arm of the jack decreases quite early, and perhaps faster than that of the weight.
Possible solutions:
Use a higher operating pressure -> pay attention to the resistance of the hoses and the cylinder seals (this is still occasional use)
Starting from a non-horizontal initial position
Put 2 cylinders and / or choose a cylinder with a larger stroke and / or section
For your information, the pump theoretically delivers 25 cm3 at each stroke of the pump.
The large cylinder chamber has a volume of 500 cm3
With 1 cylinder, it would therefore take 20 pump strokes to straighten the mast
With 2 cylinders it is double
A+
It is still a bit fair to raise the mast alone and you have to check the intermediate positions because the lever arm of the jack decreases quite early, and perhaps faster than that of the weight.
Possible solutions:
Use a higher operating pressure -> pay attention to the resistance of the hoses and the cylinder seals (this is still occasional use)
Starting from a non-horizontal initial position
Put 2 cylinders and / or choose a cylinder with a larger stroke and / or section
For your information, the pump theoretically delivers 25 cm3 at each stroke of the pump.
The large cylinder chamber has a volume of 500 cm3
With 1 cylinder, it would therefore take 20 pump strokes to straighten the mast
With 2 cylinders it is double
A+
0 x
Hello,
Thank you for your explanations and simulations answers.
What do you think with such a cylinder?
http://www.hynedi.com/PBSCProduct.asp?ItmID=1100785
Thank you for your explanations and simulations answers.
What do you think with such a cylinder?
http://www.hynedi.com/PBSCProduct.asp?ItmID=1100785
0 x
- Philippe Schutt
- Econologue expert
- posts: 1611
- Registration: 25/12/05, 18:03
- Location: Alsace
- x 33
- Philippe Schutt
- Econologue expert
- posts: 1611
- Registration: 25/12/05, 18:03
- Location: Alsace
- x 33
Bonjour,
You can place the cylinder fixing points where you want, as long as you respect the triangulation.
Example below, with the attachment to the mast that can be achieved by a through axis.
In the mounted direction, as we use a manual pump, no risk of having a water hammer, so we can take out the rod as much as possible. It's more the positioning tolerance that imposes a little margin.
In the downward direction, the piston can come into abutment in the bottom of the barrel but there is no impact. It is true that a flexible outer stop could absorb the speed at the end of the stroke and prevent the jack from supporting everything.
When the mast is almost vertical, it finds itself in balance, the weight no longer opposes the tilting and will even become leading for the last degrees.
As the operation of the hydraulic pump does not create restraint, the mast should not take too much speed before the support of the plate on the mounting base, otherwise everything will tear off and the mast will tip over to the other side.
For the descent, the flow must be throttled with the adjustable valve (see the previous document), until the desired descent speed is obtained.
Attention, the geometry of the kinematics will not allow a constant speed (variation of the lever arm)
A+
You can place the cylinder fixing points where you want, as long as you respect the triangulation.
Example below, with the attachment to the mast that can be achieved by a through axis.
In principle you must avoid arriving at the stop, it may damage the seals. 5 to 10mm of unused travel on each side are necessary.
In the mounted direction, as we use a manual pump, no risk of having a water hammer, so we can take out the rod as much as possible. It's more the positioning tolerance that imposes a little margin.
In the downward direction, the piston can come into abutment in the bottom of the barrel but there is no impact. It is true that a flexible outer stop could absorb the speed at the end of the stroke and prevent the jack from supporting everything.
What force does it need to finalize the climb and how to manage the descent, if for example I use a hydraulic cylinder.
When the mast is almost vertical, it finds itself in balance, the weight no longer opposes the tilting and will even become leading for the last degrees.
As the operation of the hydraulic pump does not create restraint, the mast should not take too much speed before the support of the plate on the mounting base, otherwise everything will tear off and the mast will tip over to the other side.
For the descent, the flow must be throttled with the adjustable valve (see the previous document), until the desired descent speed is obtained.
Attention, the geometry of the kinematics will not allow a constant speed (variation of the lever arm)
A+
0 x
Bonjour,
Below the simulation with a telescopic cylinder type 306
Closed center distance 399 and stroke 900
This cylinder has a thrust capacity of 3 tonnes at 200 bars
With the initial lever arm at 710 mm, the lifting moment is:
3000 daN x 0.710 m = 2130 da.Nm
There we have room and we are sure to raise the mast + the wind turbine.
It remains to study the rdm to verify that the bending at the push point will not deform the candelabrum.
A+
Below the simulation with a telescopic cylinder type 306
Closed center distance 399 and stroke 900
This cylinder has a thrust capacity of 3 tonnes at 200 bars
With the initial lever arm at 710 mm, the lifting moment is:
3000 daN x 0.710 m = 2130 da.Nm
There we have room and we are sure to raise the mast + the wind turbine.
It remains to study the rdm to verify that the bending at the push point will not deform the candelabrum.
A+
0 x
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