Need advice on linear motion

[Noodles24]

I am currently in the process of designing/specifying a height adjustable table within a containment, recently I was told the table will also have move on rails laterally. I have used a screw jack system to move the table vertically but I was thinking of using a rotating screw jack to also move the table laterally on the rails. It has been specified that the table should be driven manually (via handwheel) and the space requirements are very tight due to the surrounding facility/containment.

What I was wondering has anyone got anything better/different which would meet my requirements or any advice/direction on something which could do the job. The dimensions of the height adjustable table is 1444 x 1198 x 1115(Max Height) mm and it weighs approx 3 tonne when carrying a component. The amount of travel the table needs to do is 1010mm (Max) on a set of steel wheels and rail. There is approx 80mm clearence beneath the table.

The main difficulties I am having is that there is a door at the opposite end of the containment preventing a lead screw being supported at that point and there is no room either side of the table so the lead screw has to go through the middle of the table. I suppose a plummer block would be possible to support the screw but is there any way of supporting the lead screw within the design or would something else be better suited to drive the table manually?

This is my first post and I am unsure if this is the correct way to use this forum, but any advice would be much appreciated.

 

[MintJulep]

You could simply drive one of the axles through a suitable gear box.

Or place a rack between the rails and engage a pinion driven through a gear box.

Or support a power transmission chain at each end of the rails and drive through a gear and a couple of idlers.

 

[bithkits]

Are hydraulics/pneumatics an option? Reason I ask is then the manually operated foot pump/release valve may be placed further away from the table so you won't be limited by space constraints.

Adriaan.
I am a Mechatronics Engineer from South Africa.

http://www.martin-electronics.co.za

 

[Noodles24]

Thanks for the replies........The use of hydraulics/pneumatics is definatly an option.

If you both have any example applications where these systems have been used that would be helpful. I like the idea of having the manual operated gearbox/footpump being away from the table as space is the most important restraint.

 

[swearingen]

Another idea is to mount the screw to the table and the rack to the floor so that the screw doesn't have to be supported outside of the confines of the table area.


-5^2 = -25 ;-)

http://www.eng-tips.com/supportus.cfm

 

[Noodles24]

This is a 3D image of the design so far with the rails. As you can see the clearence beneath the table is minimum, and housed within the cover on the base is the AC motor driving the screw jacks for height adjustment. There isn't much room within the housing but it is possible to mount some kind of gearbox etc within that if needed.

 

[tygerdawg]

Depending upon your positioning accuracy requirements (which you did not specify) a scissor lift table may be considered. Many companies that make this type of equipment will make a custom design unit to fit your needs.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[Jmoore1]

to save the space of a gearbox setup, why not use a hand driven worm gear (can easily get 50:1 ratios and higher in a very small space) Very inefficient little devices but if its hand driven it doesnt really matter.