Counterbalance design 2

[Intrigued]

Hello, I apologize if this is in the wrong section. Because I’m quite new to everything. But I was tasked with a design that could raise and lower a small dog onto a platform about 5 feet off the ground. It Hass to be solely triggered by the dog walking onto either the lower or the upper platform to raise or lower it to ground level. I met a complete loss for locking mechanisms that would release automatically based off of weight as well as if this can be done with one independent counterbalance system or if it Hass to be too. Any input any suggestions anything at all would be greatly appreciated. Thank you so much I really appreciate any help you guys can give.

 

[3DDave]

This is usually done with a motor. There are no self-powered bi-directional elevators. Is the dog insufficiently self-powered to raise and lower itself? A doggie Paternoster would be interesting.

It's possible to make a lowering system powered by the dog and self-resetting when the dog leaves the platform. Unless the dog is available to power the lift someone else will have to add the energy to do that, if only to overcome the friction losses; it's also unlikely to be counterbalanced perfectly as the weight of the dog will fluctuate.

 

[JStephen]

What I'm visualizing is that you're making a little elevator for a dog to go up and down a 5' porch. He steps on at the top, it goes down automatically. He stops on at the bottom and it raises automatically?
In that case, it needs to be powered, not just counterweighted. And with a small dog, I'm not sure a counterweight would matter that much.
The simplest solution that comes to mind is to make it continually move up and down whenever the dog is on it, and stop when he gets off. Then depend on the dog to have enough sense to promptly get off at the top or bottom, and to not jump off when it's halfway up or down. Or, if you didn't mind the power usage, just have it moving continuously all the time, where the dog just hops on at the appropriate time.
They do make doggy stairs, which Buckley here at the house uses to get on the bed.
I find dog elevators, but manually operated by the person:

https://www.youtube.com/watch?v=inUEUIhoNSA

https://www.youtube.com/watch?v=gpf-ZP71oBY

If you put the operating switch in the dog compartment, some dogs would figure out how to work it, I'm sure.

 

[Intrigued]

Thank you both with your thoughts. Initially i was hoping to design one platform with potentially an oblong pulley/gear that would rest at the top and bottom levels (wherever the additional weight was last removed from the platform.

A little more info in case it helps. This is an attempt to raise a dog to a bed without steps/a ramp. Continuous movement of the platform cant happen, nor can that of human interaction. Granted, a dog can be trained to press a button that would raise and lower a platform but (maybe in vain) i was hoping for 1/2 platforms that would automatically raise and or lower based solely off weight differential.

Again, many thanks for your input.

 

[Jboggs]

It must be powered. Counterweights can fall under their own weight, but something must overcome gravity to raise them.

 

[Intrigued]

Jboggs - thats the reason i mentioned utilizing a latch that would lock the platform at the bottom level until it would be disengaged the next time the additional weight of the dog would be applied.

 

[MintJulep]

@Intrigued

I suggest that you go to your local hardware store and buy a simple pulley, some rope and some form of weights.

Then make a prototype of your idea to explore how it might work given the constraints of the relatively uniform and time-constant gravity field here on earth.

 

[kjoiner]

Hello,

A mechanism with an appropriately sized gas spring could allow the platform to descend and then raise itself back to original height without banging.

As others have mentioned, a system that can raise and lower something with just counterweights (gravity) is not possible:
1. If the counterweight is capable of raising a load, it cannot lower it
2. If the counterweight is capable of controlling the descent of a load, it cannot raise it.

You need a motorized device. Also consider safety when working with our furry friends.

 

[MJCronin]

Homework problem ? .... a dog elevator ? .... Really ?

MJCronin
Sr. Process Engineer

 

[SnTMan]

Watcher gonna have t'do is go to a 2 dog system. One up, one down.

You're welcome

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[LittleInch]

In an ideal world you could use a motor generator and battery and use the motor to go to go up and the generator to go down and a rechargeable battery.

In real life you need to charge the battery every so often.....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[IFRs]

I see an electrically powered lift with two pallets. One pallet is up when the other is down and vice-versa. They are linked together to make this happen, perhaps on a see-saw type rocker, perhaps not. If either pallet feels pressure (dog) the system activates and the upper pallet moves down as the lower one moves up. The dog can jump up or down from the bed and it does not matter. More than one dog can use the system to join their friend on the bed or the floor.

The cats are on their own because they don't weigh enough to triger the motor.

 

[zeusfaber]

Either:

1. Build in a short delay so the dog has time to get both sets of paws onto the platform before anything starts to move

or

2. Post the resulting video to YouTube

A.