Rack and Pinion Design Question

  • Thread starter Thread starter Jhoneine
  • Start date Start date
  • Tags Tags
    Design
Click For Summary

Discussion Overview

The discussion revolves around the theoretical calculation of linear velocity in a rack and pinion system driven by human footstep force. Participants explore the mechanics involved in translating vertical rack movement into rotary motion, considering various approaches and calculations related to power generation from foot traffic.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant seeks to understand how to theoretically obtain the linear velocity of the rack when driven by footstep force.
  • Another participant requests clarification on the initial query to provide a more helpful response.
  • A different participant suggests that the goal may be to calculate the power harvested from a person stepping on a foot plate, proposing the use of Newton's law (F=ma) to determine acceleration and peak velocity based on the net force and mass.
  • Another idea presented involves using a spring release mechanism to allow for incremental movement of the gear with each step, suggesting that even minimal movement can be amplified through gear ratios to achieve greater rotational speed.
  • One participant notes that linear velocity can be calculated from rotational velocity using the equation V = (angular velocity) times radius.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and approaches to the problem, with no consensus reached on the best method for calculating linear velocity or the overall design of the system.

Contextual Notes

Some assumptions about the forces involved, the mass of the system, and the specifics of the footstep force are not fully detailed, which may affect the calculations proposed.

Jhoneine
Messages
60
Reaction score
0
Hi, I am planning on translating a vertical rack movement to a pinion rotary motion by a human footstep force. Any idea on how to obtain the rack linear velocity theoretically ?
 
Engineering news on Phys.org
Sorry but I can't immediately see what there is to work out ?

Please explain what you are trying to do more completely and then you will probably get a more helpful answer .
 
Sounds like he's trying to work out the power that can be harvested from a man walking over a foot plate in the floor.

The rack will accelerate downwards when the man steps on the foot pad. The acceleration could be calculated using Newtons law F=ma (eg using the net force on the rack/man and the mass of the combination). From that you can calculate/estimate the peak velocity after some time t (which depends on how long he stands on the footpad.

Perhaps it would be easier using work = force * displacement
 
If speed is not an issue, per say, you could have it attached to a spring release gear mechanism. Think of a clock gearbox. You step, the plate pushes down a lever that knocks a gear a little bit, this then returns and bypasses moving the gear. Each step moves it farther and farther. Remember, in theory, even if you have it barely move the gear, you can have that gear run against a much smaller gear attached to a larger gear. Your speed has no limit.

Your linear velocity will be easily calculated given you know the rotational velocity and the radius with the equation V = (angular velocity) times radius.
 

Similar threads

Replies
22
Views
3K
Replies
5
Views
2K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 3 ·
Replies
3
Views
5K
Replies
2
Views
7K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 2 ·
Replies
2
Views
5K
Replies
2
Views
901
Replies
3
Views
4K