We have been having some issues with our Topcon GT 505 Robotic Total Station and according to our dealer it stems from us not using the screw lock?ÿon the side of the tribrach?ÿto provide more stability. Although we have not encountered any accuracy issues and our Robotic TS outperforms our older conventional TSs we figured we would try it out. The only problem is that the little screws are $235 a piece. Does anyone know where to source these cheaper? We have one that the Robotic TS came with, but we typically?ÿdo leapfrog traversing while doing large boundary work and would like to install them on several more tribrachs.
The tribrach you have in the picture is the standard tribrach for Topcon GT robots.?ÿ If yours didn't have it when you got the instrument, I would ask your dealer to furnish it, assuming you bought it new.?ÿ It should have had one on it when it arrived at the dealer from Topcon.
What you have circled in red is what I've called an optical plumb, either eye sight or laser site. Most instruments come with the plumb internal on the instrument with a see thru tribrach.
The flat knob on the left is the locking screw.
The threaded hole on the bottom of a tribrach is for the central fixing screw on the head of a tripod.
When you leapfrog it is necessary to use three calibrated tribrach with optical plumb.
I use three same tripods to traverse. Quit leapfrogging because it caused too much wear to the locking mechanism and there was always the all too much possibility of not locking something down and the occasional setup that had to be remade because a hand had made a poor setup.
I simply leave tripods in place and set another tribrach and instrument or site on top, still faster than making three tripod setups on each traverse point.
What the manufacture actually calls their parts can vary and I do remember that Topcon did not always put optical plumb on their instruments and utilized them in the tribrach instead. Decades ago when we used Topcon, most every time we would send one in for lube and calibrate it would return without the optical plumb and e always had down time to get it right. Today the shops should be more adept, then again, the last time I sent an instrument in it returned in very good shape except the seals around the scope axis that fit the covers were missing. Did not notice that for nearly a year when I put the instrument back in service and the scope would slide horizontal to the left when holding that part and turning the instrument to the right, it would spring back into place afterwards and be as good as gold.
That is why it is so important to inspect every new and repaired and calibrated unit after it returns to your office with a fine tooth comb.
That is the locking for the torque stability for sokkia/ topcon robotic which are unique to them only. however there are no cheaper ones from Seco or china counterparts. You got to purchase from sokkia and topcon direct.?ÿ
That is the locking for the torque stability for sokkia/ topcon robotic which are unique to them only. however there are no cheaper ones from Seco or china counterparts. You got to purchase from sokkia and topcon direct.?ÿ
What you have circled in red is what I've called an optical plumb
That's what I thought when I first saw the photo on my phone (I didn't even see the red circle).?ÿ When I looked at it on my desktop, I realized it was a locking screw.?ÿ Sure looks like an optical plummet eyepiece, though.
Or kludged a solution.?ÿ It seems to me that a well-designed and executed tribrach doesn't need a jam screw to hold the instrument in place.?ÿ My GeoMax does just fine without one.
The optical plummet?ÿis in the instrument NOT the tribrach. Trichbrach has pass-thru for the instrument to see thru. Therefore this is the locking screw.
I?ÿhave 3 other Topcon Tribrachs that we use for leapfrogging typically and they all have optical plummets and a set of threads for a fixing screw, but they did not come with it. We did receive that GT tribrach with the instrument, but because of the lack of optical plummet we don't use it very often.
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Posted by: Jim Frame
Crikey, they've set the bar with that one.
Or kludged a solution.?ÿ It seems to me that a well-designed and executed tribrach doesn't need a jam screw to hold the instrument in place.?ÿ My GeoMax does just fine without one.
We didn't think so either, but our dealer is insisting that a tracking problem we have is caused by not using the screw. So we are trying to cover our bases and use what they say. I have had great accuracy results and this problem only started after getting it back from the factory.
We have been having some issues with our Topcon GT 505 Robotic Total Station and according to our dealer it stems from us not using the screw lock?ÿon the side of the tribrach?ÿto provide more stability. Although we have not encountered any accuracy issues and our Robotic TS outperforms our older conventional TSs we figured we would try it out. The only problem is that the little screws are $235 a piece. Does anyone know where to source these cheaper? We have one that the Robotic TS came with, but we typically?ÿdo leapfrog traversing while doing large boundary work and would like to install them on several more tribrachs.
I have no idea whether or not this "upgrade" will help, but it sure would not hurt anything (except your wallet).
Over the years I have built, modified, and/or screwed with a LOT of survey equipment in order to "improve" it, or just to?ÿsave some money. I agree that the +$200 seems REALLY steep, but I am not particularly surprised. Considering how much money you already have invested in the GT 505, Tripods, Tribrachs, etc, I would just spend the money and not waste a bunch of time (and money) trying to do a kludge that may or may not work as well as the "factory part."
I think your clients should appreciate the cost of doing business. If they are not, just ram some bubble gum, duct tape and a clothes pin in there to hold the instrument. Seriously, save the receipt and if the screw makes no difference then send it back for a refund.
