Apparatus for establishing a line in the same plane as a reference line

Claim 2

Apparatus for surveying comprising means to establish a horizontal reference laser beam in a desired direction, upper and lower beam reflecting means each comprising two mutually spaced reflecting elements, a first element of said upper means intercepting said beam and directing a portion of it vertically downwardly, one of said elements of said lower means intercepting said vertical beam, and means relatively to adjust the position of the elements of said lower means to cause coincidence of the beam reflected from said one element of said lower means with said reference beam in one of said other elements with said beam between said elements of said lower means in the same plane as said reference beam.

Claim 3

Apparatus as claimed in claim 1 in which said other element of said lower means is bodily rotatable about said one element thereof.

Claim 4

Apparatus for surveyinG comprising means to establish a horizontal laser beam reference line in a desired direction, a means for intercepting and dividing this reference line into two beams and for deflecting these resulting beams vertically downward, and an assembly including two reflective elements, one for intercepting each of the two descending beams and means for rotating one of said elements relative to the other to reconstitute the two vertical beams into a single beam in the same vertical plane as the reference line, one of the reflective elements of said assembly projecting a beam substantially coaxial with that between said elements.

Claim 5

Apparatus for surveyinG comprising means to establish a horizontal laser beam reference line in a desired direction, a means for intercepting and dividing this reference line into two beams and for deflecting these resulting beams vertically downward, and an assembly including two reflective elements, one for intercepting each of the two descending beams and means for rotating one of said elements relative to the other to reconstitute the two vertical beams into a single beam in the same vertical plane as the reference line, one of the reflective elements of said assembly projecting a beam substantially coaxial with that between said elements.

Claim 6

Apparatus as claimed in claim 3, further comprising means to tilt said assembly to direct the reconstituted single beam at a desired vertical angle to the reference beam but within the same vertical plane.

Claim 7

Apparatus for surveying in tunnels comprising means to establish a laser beam reference line in the desired direction of tunneling, a prism assembly for intercepting said reference line beam at the edge of said tunnel shaft and for reflecting a portion of said reference line beam vertically downward while the remainder thereof continues in its original direction, a first prism at the foot of said tunnel shaft for redirecting said reflected portion approximately in the desired direction of tunneling, a dividing prism for returning a portion of said redirected reflected portion toward the surface while the remainder continues in its said approximate desired direction, a deflecting prism assembly at the surface of the shaft for redirecting the arriving vertical beam along the original laser path, means to orient said first and said dividing prisms to cause said remainder of said redirected reflected beam in the tunnel to assume the same parallel direction as the reference line.

Claim 8

Apparatus for surveying in tunnels comprising means to establish a laser beam reference line in the desired direction of tunneling, a prism assembly for intercepting said reference line beam at the edge of said tunnel shaft and for reflecting a portion of said reference line beam vertically downward while the remainder thereof continues in its original direction, a first prism at the foot of said tunnel shaft for redirecting said reflected portion approximately in the desired direction of tunneling, a dividing prism for returning a portion of said redirected reflected portion toward the surface while the remainder continues in its said approximate desired direction, a deflecting prism assembly at the surface of the shaft for redirecting the arriving vertical beam along the original laser path, means to orient said first and said dividing prisms to cause said remainder of said redirected reflected beam in the tunnel to assume the same parallel direction as the reference line.