Vibration in jack: up and down movement

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Discussion Overview

The discussion revolves around a mechanical mechanism involving a scissor lift that experiences significant vibration during operation. Participants explore potential causes of the vibration and suggest various methods to reduce it, focusing on structural stability, force application, and design modifications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes the need for the structure to be stable and to sustain weight equally to avoid vibration.
  • Another participant questions the mechanics of how the platform rises or falls and suggests that torque tubes could be added to prevent chattering and ensure a level platform.
  • Concerns are raised about the flimsiness of the base, with a suggestion to add transversal bracing for improved stability.
  • A participant inquires about the attachment points of the hydraulic cylinders and suggests that mounting them on the fixed base might eliminate the need for flexible hydraulic lines.
  • There is a request for clarification on the frequency and nature of the vibration, asking whether it manifests as swaying, rumbling, or singing.

Areas of Agreement / Disagreement

Participants express various viewpoints on the causes of vibration and potential solutions, indicating that multiple competing views remain without a consensus on the best approach to mitigate the issue.

Contextual Notes

Some assumptions regarding the design and mechanics of the scissor lift are not fully explored, and the discussion includes unresolved questions about the specific nature of the vibrations experienced.

Who May Find This Useful

Individuals interested in mechanical engineering, structural design, or those working with hydraulic systems may find this discussion relevant.

Micheal_Leo
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i have this mechanism in real life where the linkage move up and down through rollers rotating forth and back , but when mechanism move there is lot of vibration , please suggest any idea how to reduce vibration on the sides indicated by arrow .

Capture.PNG
 
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the structure should be stable and avoid vibration and also should sustain weight equally
 
What causes the platform structure to rise or fall?
How is the force applied?

To remain parallel, the scissors must be constrained for the X legs to remain parallel between the two sides, opening and closing at the same rate.

I see heavy torque tubes between the sides of the platform frame, but none between the scissor halves. Torque tubes could be placed across the machine from the fixed pivot of the scissor legs, one in the base, the other above it, in the platform. That should level the platform and prevent chattering, with a staggered, rise and fall.

There are alternatives that use flexible wires in tension, but those are more complex in this situation.
 
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If the parts forming the base on which the rollers move is as flimsy as represented, adding some transversal bracing may help.
 
Baluncore said:
What causes the platform structure to rise or fall?
How is the force applied?

To remain parallel, the scissors must be constrained for the X legs to remain parallel between the two sides, opening and closing at the same rate.

I see heavy torque tubes between the sides of the platform frame, but none between the scissor halves. Torque tubes could be placed across the machine from the fixed pivot of the scissor legs, one in the base, the other above it, in the platform. That should level the platform and prevent chattering, with a staggered, rise and fall.

There are alternatives that use flexible wires in tension, but those are more complex in this situation.
1727582446286.png

the forces on top of platform while bottom is moving also at same time , two hydrulic cylinders insatlled on top platform that asssist in motion( roller rotates)
 
Draw one side of the scissor mechanism, and show the hydraulic cylinder attachment points and rollers.

Is there a reason why the hydraulic cylinder is mounted on the moving platform, and not on the fixed base, where flexible hydraulic lines, moving with the structure, would not be required?
 
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Micheal_Leo said:
but when mechanism move there is lot of vibration
What sort of frequency are you talking about? Is it swaying, rumbling or singing?
 

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