A DEVICE FOR PORVIDING CENTERLINES IN A CONTINUOUS MANNER DURING CONSTRUCTION IN UNDER GROUND MINES/TUNNELS

摘要

We claim: 1. A device for providing centerlines in a continuous manner during construction in underground mines/tunnels, which comprises an assembly (6) having a four-arm mounting unit with four numbers laser emitting pointers and lenses for emitting laser beam in a single or in a parallel plane in four predetermined directions, such as 0°, 90°,180°and 270°, wherein the 180° arm is rotatble, the said assembly being accommodated in an antistatic housing(5,9) equipped with two perpendicular spirit levels(7,8) and power source such as dry or rechargeable cells for energizing the said laser emitting pointers, the said housing(5,9) being provided at the top surface with a ball and socket joint(2) fixed to a position adjusting C-shaped cross channel(19) for mounting onto a ceiling through a bolt(20). 2. A device as claimed in claim 1, wherein the fourth rotating arm is set at a pre-determined angle varying between 120° to 240° in the same plane or in a parallel plane. 3. A device as claimed in claim 1-2, wherein the laser emitting pointers are laser diodes provides a guide beam upto a distance of atleast 100 m. 4. A device as claimed in claim 1 -3, wherein the four-arm mounting is holding the laser units in such as way that the beams are emitted in a single or in a parallel plane. 5. A device as claimed in claim 1-4, wherein the four-arm mounting has arms in 0°, 90°, 180° and 270° directions, respectively, and in each arm provided with means such as holding plates with co-axial center holes for holding the lens and aligning the laser beam. 6. A device as claimed in claim 1-5, wherein the a roof bolt(20), pointed at one end and threaded on the other, wherein the threaded portion of the said bolt is fitted at the center of the crossed Cshaped channel and the pointed end of the bolt is grouted in the mine/tunnel roof. ^^cX"^^^^ "^^^^^^ 1VV^^^ Dated this 2005 (Chetan Kumar) Sc^nflst IPMD,Council of Scientific & Industrial Research -16-