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 help: underbody truck (scissor) hoist analysis Post Reply Forum
 Posted by: DanK ® 05/01/2007, 17:20:59 Author Profile eMail author Edit Good day. I'm looking for some assistance in designing a hydraulically powered truck hoist. This hoist is a scissor-configuration similar to the ones pictured here at this link: http://www.feedmobile(dot)com/hoists.html My concern is determining the motion of the top and bottom hoist levers as the cylinder shaft extends to lift the dump box. I'm thinking this involves some "mechanics of machines" linkage theory but I can't seem to find what I'm looking for. I need to be able to figure out the position of the levers at any point during shaft extension. I realize I can make a working assembly in Solid Edge, but there must be some way to calculate the lever motions by hand. Any suggestions would be helpful. Thank you. Modified by Administrator at Tue, May 01, 2007, 18:32:49

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 Re: help: underbody truck (scissor) hoist analysis Re: help: underbody truck (scissor) hoist analysis -- DanK Post Reply Top of thread Forum
 Posted by: jboggs ® 05/02/2007, 13:59:03 Author Profile eMail author Edit You took geometry and trig, right? Lay out the centerpoints and radius arms and go for it. You can figure out the position of the lift arm for every incremental stroke of the actuator. Every increment represents a new radius between the cylinder pivot mount and the attachment point on the lift arm.

 Re: Re: help: underbody truck (scissor) hoist analysis Re: Re: help: underbody truck (scissor) hoist analysis -- jboggs Post Reply Top of thread Forum
 Posted by: DanK ® 05/08/2007, 13:51:12 Author Profile eMail author Edit The lift arm position (the arm the cylinder pushes on) is easy to predict using the method you suggested, no problem there. It's the rotational motion of the bottom lever arm w.r.t. the lift arm that I'm questioning. Sorry I should have been more specific. Thanks. Modified by DanK at Tue, May 08, 2007, 14:55:18