Design of horizontal scissor-type extension beam
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Posted by: inventor-george

03/30/2006, 18:45:10

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I need to design a horizontal scissor type beam. This beam, extended will be 14 feet, retracted will be about 3 feet, and support one load at the unconstrained end of 50 pounds. I need help designing the members for minimum overall weight for a given vertical load deflection and side load/deflection.
I am an electronics engineer, so if I could design a microprocessor based beam, I'd be in great shape, but my mind goes mush with mechanical problems.
Any thoughts on sources to help me understand the equations defining load/stress/ deflection, etc? Weight is a major concern, as well as being able to select the deflections I want. size is not a significant issue [within reason].

Thank you,
George







Modified by inventor-george at Fri, Mar 31, 2006, 15:25:04


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Re: Design of horizontal scissor-type extension beam
Re: Design of horizontal scissor-type extension beam -- inventor-george Post Reply Top of thread Forum
Posted by: zekeman

04/02/2006, 00:32:53

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Why don't you post a sketch so we know what the mechanism looks like. You can't get answers when your question is so vague.







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Re: Design of horizontal scissor-type extension beam
Re: Re: Design of horizontal scissor-type extension beam -- zekeman Post Reply Top of thread Forum
Posted by: inventor-george

04/02/2006, 13:24:53

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The only file format this forum accepts that is under the size limitation is a gif file. Please forgive the poor quality of picture, but here is the best I can do given the constraints.

The beam attach mechanism has not been designed as yet, so the scissor appear to be able to rotate around the vertical post. That needs to be addressed, but I am mostly interested right now in learning how to design the sheet metal parts that make up the scissor for minimum weight. the beam, extended, is 14 feet, supporting a 50 pound weight at the free end. The weight is suspended by a cable, riding on two wheels as seen.


C_Scissor_Assembly.gif (25.9 KB)  






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Re: Design of horizontal scissor-type extension beam
Re: Re: Design of horizontal scissor-type extension beam -- inventor-george Post Reply Top of thread Forum
Posted by: Kelly_Bramble

04/03/2006, 08:17:37

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I agree with swearingen, I think that the arrangement you suggested would likely be unstable and expensive. How about considering an pneumatic(air)actuator on a simple guide rail? Or, a gantry type arrangement?

What are you trying to accomplish anyway? What is the target application?








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Re: Design of horizontal scissor-type extension beam
Re: Re: Design of horizontal scissor-type extension beam -- inventor-george Post Reply Top of thread Forum
Posted by: swearingen

04/03/2006, 07:19:29

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You'll need to go a good bit deeper than this forum to solve this one. A structural model is probably required and should be done by a competent mechanical engineer. Scissor arms of this size can be dangerous.

May I ask why the scissor arrangement? Can another extension arrangement be suggested?








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