Lift mechanism for plastic tray on CDLR Conveyor

[razor45]

I need to design a mechanism to lift the plastic tray (light green colored object on top of rollers) roughly 3" off of the conveyor rollers. The mechanism will have to extend in between rollers from underneath. The tray is very light weight...maybe 4 lbs. so I'm thinking pneumatic powered. The tray will have empty plastic bottles on it which will add very little additional weight. I've thought about 4 individual cylinders but I'm concerned that they would extend at slightly different speeds causing the tray to tilt and/or tip or move bottles. I've also thought about an individual cylinder with a plate and bearing guides which would lift at one speed but my concern with that approach is possible binding of the bearings. I could do a version of a scissor lift but with the weight I'm lifting that seems to be overkill. Any design ideas on this would be appreciated. This will be lifting a tray roughly every 5 minutes in production so I need something that is trouble free from a maintenance standpoint.

 

[dvd]

Guided cylinders might work for you

 

[razor45]

Guided cylinders might work for you

View attachment 2774

Yes...I have thought about that but i'm concerned about synchronizing two or more cylinders.

 

[dvd]

Are these going to be used for the pop-up roller chain cross-transfer shown in your sketch? You could get the transfer mechanism to pop-up using Airstroke Actuators - see this example. I have used these before.

 

[MintJulep]

Simple bell crank mechanism driven by a single actuator, preferably electrical.

 

[razor45]

Simple bell crank mechanism driven by a single actuator, preferably electrical.

Yes....i think a bell crank mechanism may be a good idea. I'm looking for a good example of one on the web. If you know of one please forward...thanks!

 

[goutam_freelance]

Conceptually, two scissor lifts with a single pneumatic cylinder at base may give good control on horizontality of tray.

 

[razor45]

Conceptually, two scissor lifts with a single pneumatic cylinder at base may give good control on horizontality of tray.

Hmmm....i'm not sure I follow the concept of two scissor lifts. Do you have an example?

 

[MintJulep]

 

[goutam_freelance]

Do you have an example?

Sorry, no!
But this looks to me feasible as rigid scissor links will maintain a horizontal position at the top positively. But some sideways rigidity will be required somehow, may be by providing double links (if possible) for each lift,

Another option will be to use a single piston on one side and a precision guide rod on the other.