Understanding Gas Dynamics in Piston-Crank Slider System

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Discussion Overview

The discussion focuses on understanding the behavior of gas within a piston-crank slider system, particularly in the context of using this mechanism to produce linear motion for an electric hospital bed. Participants explore the dynamics of gas compression and expansion during the operation of the system.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant inquires about the behavior of gas in the piston during the crank slider's operation, specifically regarding the implications for lifting an object.
  • Another participant explains that the cylinder's closed end typically includes an inlet and outlet port for air induction and exhaust, suggesting that gas dynamics are influenced by these features.
  • A participant describes their project involving an electric hospital bed and expresses their limited experience with mechanical systems, indicating a desire for guidance on suitable mechanisms.
  • Another participant proposes considering a linear actuator as an alternative to the crank slider mechanism, suggesting it may be simpler for the intended application.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best mechanism for the project, as there are multiple suggestions and considerations regarding the use of a crank slider versus a linear actuator.

Contextual Notes

The discussion lacks detailed technical specifications about the gas dynamics involved in the piston-crank slider system, and assumptions about the mechanism's design and operational parameters remain unaddressed.

Who May Find This Useful

This discussion may be useful for individuals interested in mechanical design, particularly in applications involving linear motion mechanisms and gas dynamics in piston systems.

Eko
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TL;DR
crank slider mechanism.
I need help understanding what happens to the gas that is being worked by the piston, in the crank slider. My goal is to produce linear motion on an object up to a certain height and I'm wondering since the slider moves back during the rotation of the crank what happens to the object I'm trying to push and gas inside the piston. Most of the help online-only deals on force analysis of the crank and the slider. Any help or reference text on this topic would help. suppose end EG wasn't closed and there was an object there.
 

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Welcome to PF.
The closed end of the cylinder will have an inlet and an outlet port, so that more air can be inducted while the piston volume is increasing, and the compressed gas can escape during the exhaust cycle. The valves may be controlled by some form of crankshaft, or simply by pressure difference.

You need to better describe why you need the cylinder to lift an unidentified object with a slider-crank.
 
:smile:thank you for the reply, its kind of a simple project, an electric hospital bed so a motor to produce rotary motion and a crank slider to convert it to linear. I am new to the mechanics of machines stuff so crank slider was the only option i thought off, If you have a better one I am up to hear them.Thanks again.
 
Maybe consider a linear actuator in the form of an electric motor driven screw.
Search eBay or Amazon for "linear actuator".
 
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Likes   Reactions: Lnewqban, Eko and berkeman
thanks that's much simple
 

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