进行坑内测量,往往要将转镜仪放置在天井里。因此给坑内底盘所需的支柱作业增加了许多困难。尤其是在底盘工事不坚固的斜坑道进行测量时,更须谨慎的按置经纬仪,以防发生支柱倒落的事故。如果采用三脚式的脚架来测量,对天井支柱设备,又應特装板壁,多费许多时间和劳力,根据以上原因,所以说天井的测量削弱了测量的能率。我们有鑑于此,乃制造了一种适合于天井测量的伸缩式脚架,以克服上述缺点。脚架的构造见第1图,:(1)是薄铜管,长度13m,直径35mm,在这薄铜管的两端 For pit measurements, it is often necessary to place the scope on the patio. As a result, a number of difficulties have been added to the work required for the pillars in the pit floor. Especially in the chassis fortification is not strong oblique tunnel measurements, but also be careful to install theodolite to prevent the collapse of the pillar accident. If the use of tripod tripod to measure, on the pillars of the pillar equipment, but also special board wall, spend a lot of time and labor, according to the above reasons, so that the measurement of the courtyard weakened the measurement of the energy rate. In view of this, we have created a telescopic tripod suitable for patio measurement to overcome the above drawbacks. Figure 1 shows the structure of the tripod, (1) is a thin copper tube, length 13m, diameter 35mm, at both ends of the thin copper tube