calculating cylinder length from stroke

[nighthawk0501]

Hey I have been looking around trying to find out how to find the retracted length of a bimba cyclinder with 2" bore. I figure there is a ratio to stroke, but I have been unable to find any numbers that make any sense.

Specifically, I am trying to find the retracted length of a 24" storke cylinder

[pufame]

Depends on your mounting style...

http://www.bimba.com/pdf/catalogs/FL_OriginalLine.pdf

[nighthawk0501]

Let me clarify, our team wanted to use a double acting cyclinder which would translate to style

31 * DXP
Adder per Inch of Stroke .15
Base Length 5.62

So how exactly is the retracted length calculated?

[artdutra04]

Let me clarify, our team wanted to use a double acting cyclinder which would translate to style

31 * DXP
Adder per Inch of Stroke .15
Base Length 5.62

So how exactly is the retracted length calculated?There isn't really a general rule of calculating the length of the cylinder, because the base dimensions vary by manufacturer, style of cylinder, bore size, and mounting options.

You will need to look through the Bimba catalog with the link provided above, and find the specific style of pneumatic cylinder that you want. In there, you will find exact base dimensions of that specific style of pneumatic cylinder, and you just add on the length of your stroke as dictated in the dimensions.


EDIT: The "Added per Inch of Stroke .15" is used for calculating the weight of the cylinder.

[Lawry Goldstein]

Let me clarify, our team wanted to use a double acting cyclinder which would translate to style

31 * DXP
Adder per Inch of Stroke .15
Base Length 5.62

So how exactly is the retracted length calculated?

I pulled out my Bimba catalog from last year which I am assuming is going to be the same as this years. From what I can see from the drawings is that when retracted the 31_-DXP with 2 inch bore has a lengh of "5.62 + Stroke" from the rear center hole to the bottem of the mounting threads.

Edit: I orgionally thought that the center hole was half way between the .44 stub, but I looked at the drawing again and I think that the .44 is actually the distance to center which would make more sense. So yeah... The thread is .88 long as far as I can tell.

So I would say its overall 6.72 + stroke for overall length, meaning 30.92" end to end compacted with no mounting hardware. The thickest part is 2.08"

As for weight it is 1.62 + .15 per stroke, so 5.22 pounds.

Hope this helps, if you want I can scan the page and upload it as an image tomarrow if you need. Bimba also has all of this on their site. They can even make Cad/Inventor models dynamicly for you if I remember right.

[MrForbes]

If you are using the clevis on the rod end of the cylinder, then figure about 7" plus the stroke, so you have 31" from pivot pin to clevis hole. Extended it would be 31 + 24 = 55" long.

(5.62" + 1.31" for the clevis = darn close to 7")

[feliks_rosenber]

I'm from a second year team without previous experience in purchasing additional cylinders and air storage tanks from BIMBA.

Could you please help me and my team find the following:

1 Clippard air storage tank 3-4 litter (Clippard Part Number AVT-32-16)
equivalent to those provided in the kit.

2 additional air cylinders 1 1/2 - 2" bore 20" stroke

1 additional air cylinder 1 - 1 1/2 " bore 25" stroke

Thank you!

[EricH]

I'm from a second year team without previous experience in purchasing additional cylinders and air storage tanks from BIMBA.

Could you please help me and my team find the following:

1 Clippard air storage tank 3-4 litter (Clippard Part Number AVT-32-16)
equivalent to those provided in the kit.

2 additional air cylinders 1 1/2 - 2" bore 20" stroke

1 additional air cylinder 1 - 1 1/2 " bore 25" stroke

Thank you!Start in the Pneumatics Manual. I believe the order form/link to order are in there. You might have a hard time with the last one though...I seem to recall that the longest (in previous years, may not apply to this year) was 24".

[MrForbes]

I found another thread about the air tanks that has a link to the clippard store, here's the part that we need, I think...

http://www.clippard.com/store/display_details.asp?sku=AVT-32-16

To find a bimba distributor, try here:

http://www.bimba.com/OrderInfo/Distributors/

but it may be wise to see if there is another distributor somewhere that has the cylinders you need in stock already.

[feliks_rosenber]

I found another thread about the air tanks that has a link to the clippard store, here's the part that we need, I think...

http://www.clippard.com/store/display_details.asp?sku=AVT-32-16

To find a bimba distributor, try here:

http://www.bimba.com/OrderInfo/Distributors/

but it may be wise to see if there is another distributor somewhere that has the cylinders you need in stock already.

Does that mean my team can order the cylinders and other items directly from the distributor?

[MrForbes]

Read the robot rules about purchasing parts, but my understanding is that you can order the parts from the distributors. Just make sure that the parts you order are legal for use on the robot! for example, only order pneumatic cylinders which are listed on the "free cylinders" page in the 2008 Pneumatics Manual (http://www.usfirst.org/uploadedFiles/Community/FRC/FRC_Documents_and_Updates/2008_Assets/Manual/2008_Pneumatics_Manual.pdf). This means that (for example) you can buy a 16" long cylinder from the distributor, but since it is not listed as one of the available cylinders on the "free cylinders" list, you cannot use it (per Rule <R89>)

[feliks_rosenber]

Read the robot rules about purchasing parts, but my understanding is that you can order the parts from the distributors. Just make sure that the parts you order are legal for use on the robot! for example, only order pneumatic cylinders which are listed on the "free cylinders" page in the 2008 Pneumatics Manual (http://www.usfirst.org/uploadedFiles/Community/FRC/FRC_Documents_and_Updates/2008_Assets/Manual/2008_Pneumatics_Manual.pdf). This means that (for example) you can buy a 16" long cylinder from the distributor, but since it is not listed as one of the available cylinders on the "free cylinders" list, you cannot use it (per Rule <R89>)

Yes thank you we will make sure that we comply with the rules.
The only problem is that the sizes do not match.
We will have to adjust to them somehow...

[MrForbes]

You should read rule <R42> about buying parts outside of North America, you are required to send an email to FIRST to get approval to use parts that are of different specifications.

[feliks_rosenber]

Well actually I have contacted our regional director in Israel concerning that matter.

I was told that as long as we purchase parts from BIMBA we do not need to get FIRST Israel's approval.

However, I'm not sure about BIMBA distributors in Israel.

I'll find out ...

Thank you for the information!