# I Gas Spring and Linear Actuator calculation...

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1. Aug 28, 2016

### a_c_e

May I start by saying hello to all and that I have visited the site before, but have yet to create an account until now. With that said, I am having difficulty calculating proper numbers for a project I am designing. Mind you, it has been about seven years since I was in any physics or "advanced" physics classes; my job more so pertaining to electrical calculations.

Intro: The idea is a welding workbench with a tilt top on it. the top is 72" wide, 36" deep and 3.25" tall. There will be three hinges welded across the front edge. The combined weight of the 1/4" sheet on top, as well as the 3" of subframing will be approximately 300lbs (I'll explain why an approximation is acceptable in a moment). Now, in theory, the 300lbs is applied at the center of the bench top. I need the lift force to exceed this however because I will be jigging framing and parts on the workbench surface before raising the bench angle. Hence, the mostly irrelevant inaccuracy of the weight aforementioned.

Problem: Now, if I could find a reasonably priced linear actuator that had a 51" path of travel (hypotenuse of bench depth) and more than capable lift force, then I would not be here. However... I can find a reasonably priced 30" path of travel linear actuator (only needing 25" if I lift from the center of the bench top). This creates a substantially higher lift force though. So, in hopes of lessening the required force, I intend on adding two gas springs (dampers/struts) to aid in lifting. I am not entirely sure that I know how to calculate how much the gas springs will actually lift if they are mounted at hypothetical point A or point B, given a 250lb max lift force for the gas springs. I also plan on adding "stands" for 30, 45, 60 and 90 degrees (braces I can rest the bench on to alleviate the stress continuously being on the actuator and gas springs).

Here is an image I took of the draft (I have yet to add the subframe for the bench top), but it should give a better idea of what I am trying to explain.

As I am sure there may be more questions to better help those who assist me, please feel free to ask for any further elaboration. Thank you in advance.

2. Sep 2, 2016

### Greg Bernhardt

Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.

3. Sep 2, 2016

### a_c_e

Thank you. I wish I had more information, but with me being in the Navy; I have not yet been able to dedicate the proper time to resolving this. I may repost a better image once I am finished reworking my draft of the design.

4. Sep 16, 2016

### a_c_e

Bump.

Update: I found a 24" stroke 1000lb lift linear actuator. However, I need to properly calculate it all still, including the gas springs.

5. Sep 17, 2016

### Staff: Mentor

Sorry, this is a bit too dangerous of a project for us to allow the discussion. Please find a good mechanical engineer in your local area, and ask for their help.