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Commentator

Join Date: Jul 2007
Location: Baudland
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### Linear Movement of Heavy Pedestals

02/08/2010 11:52 PM

Am trying to develop a solution to move 2 Two Tonnes pedestals in the linear direction

Distance of travel of each Pedestal : upto 300 mm

The Pedestal currently rests on a floor base whose surface roughness has predictably deteriorated since being installed possibly 20 years back and any attempt to move the pedestal over the surface overcoming friction is a time consuming activity involving deployment of gantry cranes to lift the pedestals and placing them at a distance that often is no more than 300 mm from its original position.

We had earlier suggested that the pedestals be placed on an array of rollers mounted on the floor so that any contact with the floor is completely eliminated. This solution was unacceptable to the people concerned as they insisted that the pedestal must rest on the floor when tests are carried out on the components that is clamped on the pedestal after the pedestal has been properly positioned.

However they clarified that they did not mind if the pedestal is lifted off the ground for movingit into proper position & then lowered back onto the floor once the desired position is reached.

Our proposed solution involves placing the roller arrays in slots cut on the floor. In normal position, when pedestal is not to be moved, the array is recessed in the floor [possibly at a level that is slightly below the ground level] and is not in contact with the pedestal that would then be resting on the floor base as normal.

[p]Once it is decided to move the pedestals, a mechanism is activated by means of which the roller array moves upwards coming in contact with the pedestal base, lifting it from the floor [feel that lifiting the pedestal by around 20 mm above the ground should suffice for the purpose of its movment] making the pedestal to now rest on the rollers, making it easy to push it either manually [human operators - current practise] or mecanically [yet to get approval for the automating/mechanizing the movement].[/p]

Would imlementing such a solution be possible?

Qualitative aims we intend to fulfill

1. System must be robust not prone to frequent breakdowns

2. Solution must be economical

3. Solution must be easy to operate

4. Amount of cutting involved fro making the slots for placing the arrays must be kept to minimum - both in terms of width of slot & depth of the slot cut.

Taking into account all these, we intend to propose a solution that would involve lifting the rollers from its recessed position to lifting the pedestals using a Hydraulic system.

Frequency of moving the pedestals: around 2 times a week

Our query:

1. Would it possible to deploy such a system that would satisy the qualitative requirements sated above?

2. Would it be possible to use a hydraulic system given the space constraints of allowabe dimension of slot that could be cut on the ground

As possibly evident from my queries, we are in the final year of our undergraduate course of Mechaical Engineering & have taken up this project as part of our fullfillment of requirements of our course.

Having no prior practical experiance in developing systems for industrial application, we also realise that htere is a wide gap in the therotical knowledge that we imbibe in College and the actual standardised practices in the industry. We hope to bridge this gap through the knowledge of the ofrum embers who participte here[br/]

Seeking the guidance of esteemed forum members whom after years of lurking on this forum & reading their posts I've come to greatly admire & respect.

TIA

:)

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Commentator

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#1

### Re: Linear Movement of Heavy Pedestals

02/09/2010 4:57 PM

Anybody with some/any inputs?! :|

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#2

### Re: Linear Movement of Heavy Pedestals

02/09/2010 10:38 PM

Is it not possible to attach 4 wheels with threaded shaft supports to each corner of the pedestal and lower them when you need to move the pedestal? Most heavy equipment that I have seen installed uses this method for moving it around.

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#3

### Re: Linear Movement of Heavy Pedestals

02/10/2010 12:53 AM

Placing rollers in the floor would be an expensive option (roller bearings, precise leveling of rollers, manufactur of the roller support chassis, precision working) and would have limitations, if there was a malfunction in the lifting mechanism then you would have to get a crane to lift the pedastal off of the rollers and then lift the rollers to get to the problem, you want something that is easily accessable if it malfunctions, you would not be able to have a trolley or fork lift drive over these recessed rollers if need be, plus the possible saftey issue for someone walking over the rollers. Rollers will only allow movement in 2 directions, what if you need to move sideways. There would be a perid of time where everything in the shop would have to move out to allow the installation of these rollers.

I agree with the previous writer's comments, attach 4 wheels or rollers at the ends of the pedestal (they could be bolt on and removable) , I would suggest using the standard 2 ton hydraulic jacks that are available in most hardware shops and relatively inexpensive and easy to replace if faulty, the wheels can be attached via brackets to the jacks which are bolted to the pedestal. the pedastal lifting could be performed by a single operator who could jack up each hydraulic jack +-10 mm at a time until the pedastal is high enough to move, a few guys together could push it or even jack it across tyhe floor, release the pressure in the jacks and the pedestals are ready for work.

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#4

### Re: Linear Movement of Heavy Pedestals

02/10/2010 12:54 AM

Had difficulty reading your post, because it was stretched laterally, but if i understand the question, you want to to move a pedestal 300mm over rough surface?

Would it be possible to jack pedestal vertically enough to apply water beneath it to be frozen by CO2 jet or dry ice to provide frictionless surface? Would then require only slight lateral pressure to reposition. The water could be retained before freezing by a ring of dum-dum, plumbers putty or caulk. Once the machine is in position the ice could be melted, the water recovered and the caulking dam removed.

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#5

### Re: Linear Movement of Heavy Pedestals

02/10/2010 2:29 AM

Have you seen the trolleys they use to move pool tables about in bars:-

They go under the middle of the table: you adjust the height to a tight fit, and, when you want to move the table you lift the levers at either end; roll the table to its new position then lower the levers again. Most bars leave the trolleys in place under the table.

You will need to figure out a way to get the frame work to engage the sides of the pedestals.

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#6

### Re: Linear Movement of Heavy Pedestals

02/10/2010 3:08 AM

This one is easy. Get some 1/2" thick plates of HDPE (same stuff as food grade cutting boards). If the floor is too uneven thicker HDPE plate or an underlying layer of steel plate may be needed. Also it is generally practical to patch small sections of damaged concrete flooring with proprietary epoxy patching materials well enough enable carts with casters to roll freely over them with heavy loads. this should allow use of 1/2" thick HDPE.

Plastic plates should be of enough width to fill in under the pedestals and with maybe half a meter longer than the width in the direction the pedestals have to move. Build up some rails on both sides and each end like a shallow box to guide the pedestal from one position to the other. Fasten it all down to the floor with bolts into female threaded concrete anchors.

Since the coefficient of friction between the flat bottom (I presume) pedestal base, whatever its material and the HDPE plastic will be low the mechanism to apply force through the distance can be small and simple; likely hand power with suitable leverage will be more than adequete.

Some other second order points to consider:

1. Simple sharp edged pry bars and a good number of temporary riser blocks will work fine to lift the pedestals up so that several HDPE plates can be positioned side by side together under the pedastals if the crane previously proposed is not available. I have used this method to lift Bridgeport sized milling machines as much as 6 inches off the floor

2. If there is too much deviation in the floor from flatness it may be necessary to file or abrade some shallow angle chamfers a few mm deep around the sharp bottom edges of the pedestal to keep it from digging into the plastic. This can be done while the pedestal is up on the temporary blocks. Similarly any seams in between two of the several blocks should be planned to be in the direction of movement to prevent edges from catching.

3. Costs per pedestal: The plastic plates should come in under US\$500 total. Total materials cost is likely under US\$1000 depending on the design of teh lateral moving mechanisms.

4. A preliminary test to determine coefficient of friction will aid determination of the mechanism to move the pedestals.

5. A simple block of 3/4" plywood will hold the pedastal in place at each position.

6. If earthquake forces or similar lateral or vertical forces are contemplated a tiedown system can be added. Suitable floor anchors should be selected for this set of conditions.

Ed Weldon

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#7

### Re: Linear Movement of Heavy Pedestals

02/10/2010 6:43 AM

Take off the roof and use one of those sky hook thingies or do what most people do and use these;

This one is 65mm H x 210mm L and takes a load of 10 T. One of these in each corner on a strip of 10mm x 100mm flat bar and Bobs' your uncle.

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#8

### Re: Linear Movement of Heavy Pedestals

02/10/2010 7:31 AM

I can't tell for certain, but this sounded like something that was going to have to be done twice a week indefinitely, so a solution that could be implemented quickly and with minimal labor seems to be ideal.

recess some cheap pneumatic bottle jacks in the floor spaced according to the locations you would need to place the pedestal and to distribute the load. The footprint on these is generally quite small. Jack up the pedestal and slide in a dolly with inflated rubber tires. It should roll well over the abrasive surface.

Anonymous Poster
#9

### Re: Linear Movement of Heavy Pedestals

02/10/2010 8:13 AM

A friend of mine once told me about a flying cut-off shear used at a company where he once worked. As I understand it the shear was mounted on two steel plates with a space between them. The lower plate was perforated and the space around the perimeter closed off. Shop air was pumped between the plates and the whole thing lifted like a hover craft. He said it could be moved by one person pushing on it.

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#10

### Re: Linear Movement of Heavy Pedestals

02/10/2010 8:18 AM

Check out a device called a slip plate. It consists of 2 plates. One is attached to the floor and the other to your pedestal. When you decide to move the pedestal, you pump gas or fluid between the plates to create a low friction film that allows easy motion in any direction. When you remove the pressure, the pedestal settles down firmly on its base.

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#11

### Re: Linear Movement of Heavy Pedestals

02/10/2010 8:35 AM

Welderman is on the right track. I would suggest that you use "V" shapes for tracks the ones attached to the machine being the perforated ones that have the air hook up since they will be shorter and the air holes will never be uncovered allowing a loss of air pressure. The ones on the floor should be bolted and grouted to the floor after leveling.

This setup allows for repeatability in movement and you can cut notches in the floor tracks (outside the air cushion area) at precise intervals that will accept stop blocks.
Then it is a simple matter to place the pedestals exactly where you want them every time.

mechtech

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#12

### Re: Linear Movement of Heavy Pedestals

02/10/2010 10:00 AM

What material is the pedestal made from? and how thick is it?

Isn't there a way to recess the wheel mechanism in the base of the pedestal instead of the floor? 4 (or even 3) heavy duty wheels attached to the underside of 4 (3) pancake hydraulic jacks and you're good to go in no time...

jus' saying...

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#13

### Re: Linear Movement of Heavy Pedestals

02/10/2010 11:13 AM

When moving any extreemly heavy loads I can only recall the young gentelman who moved the large oil tanks in the past by building a dam and floating them to their new positions..But with this problem water may not be an answer, but, I would sure look to the use of Air..A small film of air will allow movement over rough terrain and in what ever direction..Goggle, heavy loads and air..or look at American solving Inc...www. solvinginc.com.....Just a passing thought..Jim an old Okie.

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#14

### Re: Linear Movement of Heavy Pedestals

02/10/2010 1:53 PM

Hopefully the floor is thick enough to allow cutting slots

Simplifying a little by way of eliminating the need to lift in order to move by way of replacing the rollers with a screw manipulating two plates under the pedestal; one only with a screw and others merely to slide.

Similar

Or patch the floor imperfections some and scatter HDPE chips about under the pedestal and anchor eccentric wheels into the floor to rotate allowing 300mm of adjustment; typical—alignment eccentric bolt.

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#15

### Re: Linear Movement of Heavy Pedestals

02/10/2010 5:29 PM

Put a small wall around the area consisting of an upstand. Flood it and put a skirt on the pedestal. Pump in air and use the hovercraft principle. Once moved deflate and pump out.

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#16

### Re: Linear Movement of Heavy Pedestals

02/11/2010 11:17 PM

Part 01 of 02

Thank you all for taking the pain to help us with our project - much appreciated :)Please do post with more inputs and insights that you have.2 points that I should have clarified earlier but thinking it would be irrelevant did not,1. The Pedestal rests on a base into which T-slots have been drawn through its entire length for clamping the Pedestal to the base which iteself extends over pretty much the entire floor of that particualr section in the factor. So the base, though flat [not counting the age-induced surface roughness], does not really rest on a continuous surface. So trying to implement a solution that would involve developing a film of fluid between the Pedestal & base might throw up some tough challenges in front of us [project group] IMO2. Any treatment to the base that could vary the thickness/height of the base would be unacceptable to them possibly even variantions of mm [though we doubt their requirements are that stringent]. The pedestal, once properly positioned would be used to clamp newly manufactured pumps on to them in order to carry out performance charactristics tests. As part of these tests, the pump's shaft is coupled with the shaft of an electric motor. So according to them, any variation of the height of the base in the ares under the pedestal could lead to misalignment of shafts - unacceptable3. Though permitted, they've stated that they would like to keep the pedestal as close to the original [as it is in the current condition] as possible with the amoung of machining & modifiactions made to the Pedestal & base to the minimum.

@Maths_Physics_Maniac @Basco

SirAre you suggesting a solution that involves the use of Rotory Hydraulic actuators to operate the screw thread that would then push the wheels downward thus lifting the pedestal off the base. Would such an arrangement not involve the use of an actuator for each wheel - essentially 4 actuators needing to be controlled simulataneously for proper alignment of the pedestal. Also as we've come to conclude, since the actuators are mounted on the pedestal and the pedestal moves it would mean that the hoses/tubes that would supply fluid o the actuators too would need to be arranged to facilitate motion of the pedestal. Wanting to provide a solution that is effective & safe [among all the other ideal features that we could cram in w/o making it a project deemed fit to be rejected purely on monetary conserations] we were looking to ensure that the motion of the hydraulic portion of the system is restricted to performing up & down motion only - moving it along with the pedestal would probably increase the failure tendency of the system - to be avoided IOO.

@Basco

Sir,As has been told to us the pedestals are moved only in the direction as shown in the diagram above. In the eventuality of them having to be moved in a different direction, I guess they would not mind deploying the gantrey cranes they have, which is how they do the rough positioning of the pedestal [after which the grunt work happens]. As for the possiblity of somebody slipping on those rollers, considering that the range of motion to be achieved by the pedestal is minimal, the lenght of the array of roller palced would not make the place as accident prone as it might seem. Thank you for raising these points - helped us take into account these factors too in our evaluation of the situation.Could you please elaborate how the mechanism you mentioned in the second paragrpah would work. Facing some issues visualisng it :)

@packrat561

As mentioned at beginning of this post, the floor has T-slots cut into it through the entire length of the base that extends to better part of a significantly larger test rig section. Developing films on such a surface involving the possibility of sealing som portion of the T-slots to create an air tight section feels like an idea a bit too much of a challege for it would involve areas of engineering & manufacturing we are not very confident about being able to implement successfully.

@Randall

@Ed Weldon

Sir,Sorry for not mentioing in the post earlier, but any solution that could change the height of the pedestal from the ground would be a serious no-no for them. Please do corrct us if we are wrong, but would your soultion not change the height of the pedestal from the ground. We could place the HDPE sheets in line with the floor by attempting to machine the T-slott base so that enough material is removed from its height so that when the HDPE sheet is placed underneath the pedestal its height above ground remains same. But as we envisage your soultion, the HDPE sheets would completely block all the T-slots underneath the pedestal - unacceptable since after they've been moved the pedestals have to be clamped to the ground & also possibly due to the fact that we've machined the T-slot base for placing the HDPE sheets there may not be the required slots avaiable anymore.If this is indeed the way you've suggested we move the pedestal, then we thinnk it may pose some challenges for us to implement if approved. Please do point out any mistakes in our understadning of your soultion

@JIMRAT

From the picture it appeared to us like a series of recirculating rollers. However we were not quite able to recognise where this mechanism is normally used especially since you mentioned something about taking off its roof. Could you please help us understand this mechanism better. You also referred to a sky hook. So are you suggesting a sky hook mechanism attached to these to be used to from moving the pedestals. Could you please elaborate on your post - did not quite understand it well.TIA :)

@tpiecora

You suggested placing Bottle jacks underneath the pedestal to lift up the pedestal. But then would such an arrangement not mean that when the pedestal moves, at some positions . We were aslo wondering how reliable & long-lasting would the inflatable rubber tires would be for the application.We will have this solution in mind Thank you

@Guest, welderman, @mechtech, @jtd405 & @Pj3ns3n @Pj3ns3n

We were taking a look at Air Bearings & aslo Slip Plates and other mechanisms that you all have suggested for generating air film. Will look into it :). But then if such a solution is accepted then it also ends up rendering our project appear small and not so substantial - a reason that has lead to questioning oursevles about our decision to take it up in the first place We were hoping to cut two grooves under the ends of the pedestal earlier for rollers. We will include it as one of the solutions we'd be putting in front of them - a soultion involving air films

@Rick@cae

The pedestals are made up of MS. We were thinking of providing htem with a soultion involving the use of a Pad Jack using which it could be lifted up from the ground for movement. If this is what you've suggested, then what strikes us was the fact that if we extrapolate on the idea suggested by @Randal and try to implement a hydraulic solution we would end up using only two hydraulic jacks for the motion - more economical IOOPlease feel free to ppoint out any wrong notion that we may have.

@bwire your soultion involves employing a vice like mechanisam for motion. Please point it out if we are wrong, but we believe such a mechanism would have to make use of differential screws as we had also been told that the pedestal must have the ability of move with accuracy of 1 mm if required [especially so if the movement is to be made by means other than push applied by human workforce]Also since the motion you have suggested is sliding motion as opposed to the rolling motion involving use of rollers, would this not involve having to overcome greater friction to achive movement especially so since the pedestal continues to remain in contact with the base that is not very smooth to slide on.We probably did not visualise you soultion correctly. Would it be possible for you to explain it a bit morethank you :)

part 02 of 02 of this post in an hour - need to get out of this stuffy room cloistered into which for nearly the past day :)

In the meanwhile please give your inputs & any help us clear any wrong notions that we have exhibited :)

Thank you

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#17

### Re: Linear Movement of Heavy Pedestals

02/12/2010 12:40 AM

Slugger,

The picture is of a linear table enabling accuracy greater than 1mm, these devices are designed specifically for your type requirements with weights up to and exceeding 5 tonnes. Linear tables provide a low friction movement as the load is spread over the area of the precision way.

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#18

### Re: Linear Movement of Heavy Pedestals

02/12/2010 2:23 AM

First of all many thanks for getting back to us all and for clarifying the job in hand.

I should now clarify my post.

Take the roof off ( the factory ) and use a sky hook ( the sort of thing you send young and green people off to obtain so you can get on with the job. ) i.e. a joke.

The picture is of a "SKATE", these are used to move machines and pedestals around a factory. I have been using skates for over 40yrs and thought they were commonplace. I expect that REID SUPPLY would have them. The one shown is only 2.5 inches high x 8 inches long with a load capacity of ten tons. As you can imagine the rollers are small diam. and a two ton skate, though well able to take the load may have trouble with the 'rough' surface. I thought it would not be too hard to lift an end and place two skates under, then lift the other end and place two more. A lift point on the pedestal could be a piece of angle bolted/fastened on each end then two crow bars .....ohhh you do the math. Or it could be a hole drilled to suit the crowbar.

Maybe the men on the end of the crowbars will need to go on a special diet of beer and pizza to get the mass required to lift the pedestal. Do you think you could get some volunteers?

If the lifting with crowbars doesn't appeal you could bolt/fasten an angle point centrally on one end and two on the other end and use 3 auto trolley jacks. These already have wheels and can be used to move the pedestal. The only problem here is that they tend to slip off the lift point. But that is easily fixed by fitting the end of the jack into a 'cup'. If you go with this i would strongly suggest using 3 jacks, i am sure you can work out why!

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#19

### Re: Linear Movement of Heavy Pedestals

02/12/2010 5:56 AM

the connecting beams is to be done away with for our project.

I was hoping you would be able to design a frame work which would:-

Drop over the top of the pedestal.
Clamp to the sides.
Lift using long levers.
Move.
Lower.
Un-clamp.
Remove.

You probably only need to lift it a gnats cock to get it to clear the unevenness of the
floor: so will it matter if the pedestal tilts slightly between raising/lowering each end?

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#20

### Re: Linear Movement of Heavy Pedestals

02/12/2010 1:19 PM

Slugger -- I commend you for your sincere interest and appreciation you've shown for the various answers we have given. All to many questions posted on CR-4 contain sparse information and are followed be relative silence on the part of the OP.

I'd like to take this opportunity at this point to mildly criticize the manner in which you presented your original question. These forums are not a case of a learned professor presenting a problem to students and trying to generate creative thinking and a demonstration of competence in an answer. I realize that this is a habit picked up in the university and it stays with some young engineers longer than really necessary. But out in the real world our first priorities are the demands of customers and if engineering problems stand in the way of that we get on with the solution. Training young engineers is much secondary issue.

Here it is more like a customer approaching a conference room full of independent consultants with a problem needing a solution. The nice thing about CR-4 is that these many "consultants" will provide answers asking little more than that you accurately and completely describe the problem to be solved and also show a degree of respect for their knowledge and willingness to share. Please note that what we don't do is send you an invoice containing numbers with lots of zeros in them.

The first thing these consultants would do following you problem presentation in such a venue is ask you to describe in detail the use of these pedestals and the commercial (or otherwise) setting in which they are used. Perhaps it is in a factory, perhaps on shipboard or maybe even a battlefield. The consultants, being experienced engineers, know full well that surrounding conditions can vastly influence the correct selection of equipment.

Should you stand there and say there is no further information available due to trade secrets or "that's all I know" or some such rubbish the room will start to empty and the first ones out the door will likely be the best people to provide your answers.

In this case I know for a fact that your audience, at least from the start, contained some people with deep experience in the manufacture and application of heavy duty industrial and utility pumps. I am one such that has remained "in the room".

So I will offer this for whatever it is worth to you:

On the commercial test stand at Worthington Pump in Harrison NJ (circa 1960's) there were a large number of t-slot test pedestals that were moved about by one or another of the bridge cranes (largest was 100 tons IIRC). Most of the floor of the high bay was flat concrete but the test tanks in the floor generally had steel plate covers with attachment points for lifting. There were a number of large AC test motors and several steam turbines one of which was a 12,000 HP monster for testing boiler feed pumps. These were more or less permanently in position and pumps being tested were moved into place as required. At the Standard Pump manufacturing facilities in East Orange, NJ (Ampere) smaller pumps up to maybe 200 were tested in a similar facility with lifts being made with jib cranes. The smallest pumps were tested on fabricated steel test benches at workbench height. In almost all cases, both Harrison and Ampere, pumps tested on the calibrated test motors were coupled to the motor with cardan shaft couplings. The reason for this is that the practice of shimming mounting pads to get proper coupling alignment for most any of the common jaw, geared, flex wire or rubber couplings was expensive and time consuming . Also human error in the process of aligning couplings could cause overloads on pump bearings during test and expensive warranty problems later on.

One might then ask why pump mountings aren't machined with sufficient accuracy to avoid the shimming process. This is complex and better left to another topic. Suffice to say here that two centuries of experience in the world of machinery has shown that such practice is only practical for small machines such as those with close coupled flange mounted motors or cylinders where alignment surfaces are concentric with shafts, take advantage of the natural rotational accuracy of the engine lathe and the self-centering characteristic of press fitted round members.

Back to the question at hand: One way I can think of to move these t-slotted pedestals with sufficient accuracy to permit pump testing with conventional couplings (and rigid pipe connections) neither of which should be allowed to impose excess forces or moments on pump shafts or casing pipe connections is to imitate the arrangement of a large machine tool table such as found on a planer or gantry mill. Note that the such machines require either substantial steel or iron structures combined with engineering concrete foundations to maintain dimensional alignment.

Another possibility which would require some experimentation and development effort would be a three point slider on rail system, perhaps with my suggested use of polymer surfaces to reduce friction. Noting that three points under a rectangular structure leaves at least one or probably two somewhat cantilevered corners the addition of easily adjustable anchor bolts and a simple laser alignment system to verify final positioning might prove to be most practical.

In the end analysis I think I would prefer the cardan shafts and some flexibility in the pipe couplings and stop worrying about last millimeter of alignment. If cost is an issue I'm sure a competent millwright and machinist could contrive the needed cardan shafts from automobile and truck driveshafts, universal joints and bored and keyed coupling parts.

Ed Weldon

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#21

### Re: Linear Movement of Heavy Pedestals

02/12/2010 10:17 PM

aye mate good one. I put out the linear table thinking it may turn on a light. One them plus several other support an alignment devices ...............

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#22

### Re: Linear Movement of Heavy Pedestals

02/13/2010 2:46 PM

Post 2 of 2

I'd first like to apologise for this much delayed second post even though I'd promised to post the 2nd much earlier. Somebody had messed with the LAN connection in the hostel knocking off connectivIty till a few hours back [a disgruntled/experiment-savvy student sys admin are believed to be the culpprits :(].

Having gone through the various solutions posted here, we realised that the solutions offered that would in fact work just as perfectly are also quite "visually plain". Not having realised the relative simplicity of the task at hand & now being unable to take up a different project, we are to succesfully execute this project taken up. While we were having our project meeting a little after the 1st replies started getting posted, we thought it would be best if we provide them with a solution that not only is sound from an Engineering pov [an absoulte MUST] but is also "visually significant" [the actual term we'd all come up with was that it must look *Awesome* :)].

So in keeping this in mind and incoroporating solutions provided in the replies, we put together this design concept

Bigger-sized drawing: http://img39.imageshack.us/img39/618/movablehydraulicjackass.gif

Bigger sized image: http://img192.imageshack.us/img192/8515/movablehydraulicjackpar.gif

Bigger sized image: http://img130.imageshack.us/img130/9499/hydraulicallyoperatedsc.gif

1. It involves mounting Hydraulic Jacks as suggested by @Basco on to a base, whose dimension would be sufficient to house the jack. Each Pedestal would be coupled to 2 Jacks positioned at its end

2. To the Base we would attach Skates [h/t @JIMRAT] that would be constrained to move in the linear direction by means of guideways that is either recessed into the floor making it in level with the base or the guideways could be clamped on top of the base using the T-slots running underneath it [ie. the T-slot cut base].

3. In the normal inactivated position the Hydralic Jack cylinber is retracted and the pedestal is resting on its base on top of the exiting T-slot cut floor.

4. However if the operator wishes to move the pedestal laterally [as depicted in the pictures on my first post], he [no blue-collared female operators in the factory :|] shall activate the jack lifting up the 2-tonne pedestal from the base by a distance of no more more than 20-30 mm as originally envisaged [a variation of what @Randall had suggested]. The cylinder of the jack could be clamped to a bracket welded on the side of the pedestal - they had informed us that such a weld capable of sustainging a load of 2 tonnes can be performed in-house as has been done to attach 2 rectangular rings for hooking it up with the bridge crane [& not gantry cranes as I had erronously stated earlier H/T @Ed Weldon]

5. With the Pedestal off its base & resting on Skates, the operator operates the Hydraulic Scissor mechanism that would either move the pedestal away from each other or towards each other depending on the requirement. We are looking to operate the Scissor link with the help of a Hydraulic Hand pump .

A fact that we'd like to point out is that when the pedestal are at its innermost position, the smallest dsistance between them is 110 mm. Though the innser surfaces are inclined outwards & thus offer more space if clamped upwareds, we were wondering if 110 mm be sufficient to clamp the mechanism between the pedestals that would have to be seperated by upto 660 mm maximum [shown in the picture] depending on the pump to be tested later.

Having put forth our concept before you, do you all feel that this solution would satisfy the following conditions

1. Sound Engineering concept

2. Not liable to suffer frequent breakdowns owing to component failure

3. Economical [installation & running]

4. Ease of operator handling [a single operator IOO can now do the job]

5. Visually significant

We beilieve that the 5th condition is probably a factor that none of you might have had to take into account while designing solutions, but keeping that condition in mind, would would love to hear your views on this solution

A doubt we had: Is it possible for perform accurate motion control with the help of the aforementioned Hand Pump we propose to install? In order to achieve positional accuracy of the pedestal the floor has a distance scale bolted to it for information. We were hoping to keep it as it is and make use of it to achieve the required distance between the pedestals

@bwire

An issue that would need to be tackled if we use recessed Linear Tables would be that of power transmission. A directly coupled prime-mover shaft would then also have to be positioned horizontally meaning recessed into the base. Though we could develop a gear tranmission system to transmit power to the recessed table. If the solution of a linear table is approved, we'd hve to calculate the torque required to rotate the screws which we would do in time. However would you have any experiance in suggesting if a such a linear table that has a 2-tonne load placed on it be moved using a Handwheel

@JIMRAT

Lost you on the humor the first time Sir - nice :) Also we hope to convince them of adopting a semi-automted soultion for moving the pedestal. Will keep your soultion in the bag - will whip it out if things start going awary in the meeting tentatively fixed on Monday :)

@Randall

Sir,As said to @JIMRAT, we hope to convince them of adopting a semi-automated solution as shown in the illustration above in this post. Clamping the frames from the sides might not be an issue. We've been assuared of welding in required attachments to the side of the pedestal of the required strenght for any purpose

@Ed Weldon

Thank you Sir for your very enlightning and a much informative post post. It only reenforeced the already known fact that there is indeed an extremely a wide gap that we'd have to brdige between the bookish theoritical knowledge that we as Engg Undergrads acquire and current trends, practices & working methodology in the real world as you've very rightly pointed out. I'm afraid that suggesting the company the to change the kind of coupling they should be using would be beyond the brief of our project, ie, assuming they're indeed using a different coupling that requires a very high positional accuracy of the coupled shaft [though reading through your example we feel that it is just their way of getting the best possible result w/o having to pay us anything for any successful solution that we would provide]. Though we could make this suggesstion to the Junior trainee Engineers in the company we hang out with, who could make this suggestion to their superiors, but everything would then be based on uncertainity involving various uncotrollable variables - not a path we'd like to venture into for now.

Having gone through all the valuable posts made by members and the simplicity of solutions, we feel that we made an error in judgement in taking up this project. A similar post made before we accepted this porject would have saved us from this predicament

We'd love to hear your views on the concept whose drawings we have posted here

TIA :)

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#23

### Re: Linear Movement of Heavy Pedestals

02/13/2010 3:34 PM

However would you have any experiance in suggesting if a such a linear table that has a 2-tonne load placed on it be moved using a Handwheel

Hand crank option yes with typical NEMA 23 & 34 mounts, metric mounts and motor wraps.

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#24

### Re: Linear Movement of Heavy Pedestals

02/13/2010 7:04 PM

If you were to attach stepper motor controlled, recirculating ball screws to your carriages you could use a computer to accurately separate your TWO pedestals.

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