AJ12-A4 Tribrach without Optical Plummet Leica Type Green For Survey Equipment

AJ12-A4 Tribrach without Optical Plummet Leica Type Green For Survey Equipment

Model: AJ12-A1

Overview:

Leica type Tribrach Replacement of Original GDF121

Specifications:

Features:

A. Replacement of Leica GDF121 Tribrach

B. High quality features 3X magnification and a twist focus.

C. With locking forced-centering knob.

D. 5/8*11 base

E.8-minute circular bubble

F. Large-diameter leveling screws

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  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