The linear spring having even forcing pull/push

Click For Summary

Discussion Overview

The discussion revolves around the concept of achieving a linear spring mechanism that provides an even pull/push force across a range of motion. Participants explore various types of springs and mechanisms that could potentially fulfill this requirement, including theoretical and practical applications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the feasibility of creating a linear spring, particularly a spherical spring, that delivers an even force across a specified range.
  • Another participant suggests that an air spring with a large accumulator can provide a nearly constant force over a displacement range, citing gas struts in hatchback cars as an example.
  • Belleville springs are mentioned as a design that can achieve constant force over part of their displacement range, with a reference to a graph illustrating this property.
  • A servomotor in torque mode is proposed as a method to maintain constant force throughout a range of motion.
  • Complicated linkage arrangements are mentioned as a potential solution, although details are not provided.
  • A clock spring is noted for its ability to provide a constant force, with an example of its application in a "Product Pusher" used in grocery stores.
  • A participant describes the Fusee modification of a clock spring, which utilizes a cylinder with varying radius and a chain to maintain even torque over time, highlighting its effectiveness in a school clock.

Areas of Agreement / Disagreement

Participants present multiple competing views on how to achieve an even pull/push force with springs, with no consensus reached on a single solution or method.

Contextual Notes

Some limitations include the dependence on specific spring designs and configurations, as well as the unresolved nature of the proposed mechanisms and their effectiveness in achieving the desired force characteristics.

abdulbadii
Messages
43
Reaction score
1
TL;DR
Need a matter or configuration of linear spring direction with even forcing pull/push
How do we have linear spring direction (mostly a spherical spring) to have pull/push force evenly across some points within a range?
Or is it possible to create spring material with anomaly property capable of performing so?
 
Engineering news on Phys.org
If you want a spring that provides a constant force over a range of displacement, there is more than one way to do it.

An air spring with a large accumulator will have almost constant force over a displacement range. The gas struts used in hatchback cars are one type of air spring.

Belleville springs can be designed for constant force over part of their displacement range. A quick search found this graph that shows this:
Belleville.jpg

It is possible to use a servomotor in torque mode to provide a constant force over a range of motion.

I believe that there are also complicated linkage arrangements that can do it, but have not looked for such.

And last, but not least, search constant force spring.
 
  • Informative
Likes   Reactions: berkeman and anorlunda
A clock spring does a pretty good job of constant force. The same approach is used in a "Product Pusher", as used in grocery stores to keep products at the front of a shelf.

At the site below, the outer end of the spring is attached to the rail. The inner end of the spring is not attached. As the vertical part is moved to the left, the spring is forced to straighten (unwind) with an almost constant force.

https://www.dgsretail.com/A0638/spring-loaded-shelf-pusher-black-2-5h-7-5w

Cheers,
Tom
 
  • Like
Likes   Reactions: sophiecentaur and Lnewqban
abdulbadii said:
TL;DR Summary: Need a matter or configuration of linear spring direction with even forcing pull/push

How do we have linear spring direction (mostly a spherical spring) to have pull/push force evenly across some points within a range?
The Fusee modification of an old fashioned clock spring uses a cylinder with varying radius and a chain to provide very even torque over the whole week's worth of winding. We have a school clock (short pendulum) and its timekeeping is really pretty fair until the time it needs winding when it speeds up by about a minute. The light chain is pretty cool but I have heard of a pierce of gut used for the same purpose.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
Replies
6
Views
1K
Replies
4
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
6
Views
1K