Rod that slides up easily but slowly on way down

[manp]

I'm sort of stuck on a fiddly point at the moment. I'm trying to make a rod go upwards with ease but slow down on the way down (or even stop for a few seconds) when it has been completely let go by the pulling action (without any external energy). Anyone have any clues of how I can achieve this? Please ask me questions for additional details as I may have missed out vital points to include in my post.

 

[mfb]

Something like a ratchet?

 

[berkeman]

I'm sort of stuck on a fiddly point at the moment. I'm trying to make a rod go upwards with ease but slow down on the way down (or even stop for a few seconds) when it has been completely let go by the pulling action (without any external energy). Anyone have any clues of how I can achieve this? Please ask me questions for additional details as I may have missed out vital points to include in my post.

Something like a ratchet?

Or a hydraulic shock absorber mechanism with 1-way valves for different damping rates for the up and down directions...?

 

[Travis_King]

Or a hydraulic shock absorber mechanism with 1-way valves for different damping rates for the up and down directions...?

My first thought exactly

 

[256bits]

A hand bicycle pump come to mind.

 

[manp]

Thanks all, I've got a superb idea now, I am going down the ratchet route although a hydraulic type pump was also a good idea but takes up a small amount of pull energy due to the tight conceals I would've had to put around it. Whereas with the ratchet design I'm thinking of there would be almost no extra energy needed and more crucially I can time it to execute an exact timed drop. Cheers all, this forum is the best :)