compression spring mechanism

[Fra89]

Good evening, everyone!

I have to build a mechanism according to the scheme in the image
testwz.png

in d there is an electric motor that moves everything. the mechanism must make a small fraction of turn, but it must be able to move in both ways. on the bc rod I have to mount two springs that work only compression, one when the motor rotates clockwise, the other when rotates counterclockwise. The springs must also have a preload. I schematized this system of springs with a figure (of course it is only a theoretical design to understand its functioning).

58922918.png

the "black body" in the figure moves left or right moved by the electric motor, and compresses only one spring x time, according to the direction of the movement, while the other remains blocked by a kind of "end run" that should also work as a preload for the spring.
the question is: how can I realize the system of springs that functions according to the theoretical principle that I explained before?

thanks to all:smile:

 

[meccanicamg]

to say the truth I'm not sure I understand very well, however if you want the springs to remain in maximum extended position without making elastic contribution just that the left spring holds it bound to the left side and the dx spring bound to the right side. you can use a compass, shaped that keeps the spring, a saucer, what you want

 

[Fra89]

first of all thanks for the answer. .

Actually the springs must be precompressed, so there is a need for something that keeps them firm with some initial compression. What I wanted to say is that the spring system as I designed it can only work in a school exercise, while I really need to realize something that allows me to work the springs like that.. how could I do?

Thank you.

 

[meccanicamg]

a solution to be able to develop can be this attached. the technical modes of execution can be numerous, expensive or not, of small or large dimensions.

 

[Fra89]

I apologize for my absence, but unfortunately these days I have not had internet access..
the idea you designed is good, unfortunately all the mechanism must be as compact as possible, both in terms of size and weight. .

 

[meccanicamg]

Well, you have to work on weight and compactness. I don't have any given of forces couples and sizes. Good chilling. Remember that if you have to realize it you must not break and attentive to the calculation of the springs

for compactness you can achieve the postponement of the bar not to z as from my scheme but use a fork to y so as to remain radially compact.

other solution is to mount all the mechanism in a telescopic tube.

 

[Fra89]

Forgive me if I'm a bit pressing and I still ask you a few questions, but since you're very helpful, I feel a shame not to take advantage of this opportunity I have to learn something! :
how attentive to the calculation of springs? for the springs I simply chose from the catalog what I thought suitable in terms of working length and maximum permissible load.. Plus I decided to make the spring work sufficiently far from the conditions in which it goes to package, both to be able to have an adjustable preload, than to preserve the integrity of the mechanism.. is there any other parameter to which I have to pay particular attention?

for the mechanism, perhaps the telescopic tube is a better idea.. the forces in play are low, so there should be no big problems for the mechanical resistance of the components. .the order of magnitude is about 150 n to traction or compression. .

 

[meccanicamg]

Forgive me if I'm a bit pressing and I still ask you a few questions, but since you're very helpful, I feel a shame not to take advantage of this opportunity I have to learn something! :
how attentive to the calculation of springs? for the springs I simply chose from the catalog what I thought suitable in terms of working length and maximum permissible load.. Plus I decided to make the spring work sufficiently far from the conditions in which it goes to package, both to be able to have an adjustable preload, than to preserve the integrity of the mechanism.. is there any other parameter to which I have to pay particular attention?

for the mechanism, perhaps the telescopic tube is a better idea.. the forces in play are low, so there should be no big problems for the mechanical resistance of the components. .the order of magnitude is about 150 n to traction or compression. .

the conditions regarding the springs are those described by you. get her to work about 50% and don't let her pack. pay attention to the frictions of the sliding systems and to the weight of the beams that are an element of variation of the system law you are analyzing.