Leica Type Green Tribrach without Optical Plummet for Survey Total
Station GPS
Model: AJ12-A1
Overview:
· Suitable for TPS instruments with an angular accuracy of greater
than 3".
· The footscrews have a large diameter which permits fine
adjustment even when wearing work gloves.
Specifications:
| Color | Circular Bubble | Torsional Stiffness | Leveling Screws |
| Pale green | 8-minute | <3" | Large-Diameter |
Features:
1. Replacement of Leica GDF111-1 Tribrach
2. High quality features 3X magnification and a twist focus.
3. With locking forced-centering knob.
4. 5/8*11 base
5. 8-minute circular bubble
6. Large-diameter leveling screws
Introduction:
Suitable for TPS instruments with an angular accuracy of greater
than 3". The footscrews have a large diameter which permits fine
adjustment even when wearing work gloves. Torsional stiffness
<3", weight 780 grams
Tribrach
A tribrach is an attachment plate used to attach a surveying
instrument, for example a theodolite, total station, GNSS antenna
or target to a tripod. A tribrach allows the survey instrument to
be repeatedly placed in the same position over a surveying marker
point with sub-millimetre precision, by loosening and re-tightening
a lock to adjust the instrument base in a horizontal plane.
What is the accuracy of a tribrach?
The accuracy with which a tribrach returns to its starting position
once the instrument has stopped, is called torsional rigidity or
hysteresis. This hysteresis is the relative movement between the
top plate and the base plate of a tribrach that occurs through the
rotation of a TPS instrument.
Why does a tribrach need to be adjusted?
The precise alignment of the support area to the base plate of the
instrument assures extremely accurate forced centring. The optical
plummet is so robust that the need for adjustment during the entire
lifetime of the tribrach is practically unnecessary.
How big are the foot Screw on a tribrach?
The hysteresis of the Professional 3000 Series tribrachs amounts to
a maximum of 3" (1.0 mgon). The foot screws are maintenance-free
and have a larger diameter.
Detailed Pictures for Reference
