Sighting assembly

A sighting assembly for providing a reference laser beam in the course of connecting pipe segments to each other includes an elongate body in which a laser pointing course is received and which is pivotally engaged at its front end to an straight edged arm. The body may further include a magnetic compass and a level assembly, both proximate its rear end, to provide a visual indication of the azimuth and inclination thereof. These are achieved by an azimuth ring on the compass projecting into lateral cutouts in the body for manipulative convenience. In one example the arm supports two spaced posts, each including spaced projections for contacting the pipe segment, and when the arm is collapsed below the body for storage the posts are received in the cutouts.

BACKGROUND OF THE INVENTION
 1. Field of the Invention:
 The present invention relates to sighting devices, and more particularly to
 laser beam sighting assemblies useful in aligning pipe segments and
 flanges in the course constructing a pipeline.
 2. Description of the Prior Art
 The process of constructing a pipeline or pipe run often entails a sequence
 of welds in which long segments of pipe are joined to bend segments and
 flanges. In this process the accumulated build up of welding tolerances
 and welding heat distortions require continuous realignment sighting, with
 compensating grinding adjustments made at each weld joint. Thus the pipe
 fitter is constantly measuring angles, adjusting the weld lines and
 re-sighting in order to obtain a proper drainage slope and a true flange
 surface at the end of a run.
 Maintaining a proper slope and flange surface alignment is particularly
 difficult at a pipeline bend. Here the length tolerances compound the
 angular tolerances and the pipe fitter therefore needs to adjust both the
 length and the angular segment of the bend to maintain slope and flange
 geometry. In this setting various sightings are taken along the pipe and
 the bend segments which with the use of trigonometry resolve the final
 flange joint plane.
 This cumbersome process renders any construction assignment in which the
 pipe run needs to drain in a particular direction both difficult and
 geometrically indeterminate. For example, typical drain slopes are 1/8 or
 1/4 inch per foot and any distortion or misalignment of the bend can form
 undrained traps or pockets that promote corrosion. Thus a continuing
 requirement subsists for a quick verification of the slope and its general
 direction as the pipe segements are welded.
 Heretofore various surveying assemblies have been devised which in one or
 another manner provide accurate measurement of the various geometrical
 points and lines. Examples of such surveying assemblies are shown in U.S.
 Pat. No. 3,813,170 to Sears; U.S. Pat. No. 3,897,637 to Genho; U.S. Pat.
 Nos. 4,973,158 to Marsh; and 5,218,770 to Toga. While each describes an
 accurate surveying instrument, the precise and complex surveyor's
 procedure is not practical at each weld and therefore primarily useful to
 set the end references or the reference line. Alternatively, portable
 measuring devices have been developed incorporating complex electronic
 systems that render convenient most remote measuring tasks, exemplified in
 U.S. Pat. Nos. 5,075,977, 5,287,627 and 5,182,863, all to Rando. While
 suitable for the purposes intended each of the foregoing entails complex
 precision instrumentation that is expensive to produce and maintain and
 subject to damage.
 A simple, inexpensive and rugged sighting assembly particularly suited to
 the quick slope and azimuth adjustments made in the course of welding a
 pipe run is desired and it is one such assembly that is disclosed herein.
 SUMMARY OF THE INVENTION
 Accordingly, it is the general purpose and object of the present invention
 to provide a sighting assembly useful in determining the general slope of
 pipe bend segments in order to align the end flanges of a pipeline.
 Other objects of the invention are to provide a simple and rugged sighting
 assembly useful in the construction of pipelines.
 Yet further objects of the invention are to provide a portable sighting
 assembly conformed for quick resolution of geometry in the course of
 constructing a pipeline.
 Briefly these and other objects are accomplished within the present
 invention by providing a portable sighting assembly characterized by an
 elongate body including a pivot proximate one end from which an arm of a
 protractor is frictionally deployed. A laser beam pointer is fixed to in
 the body, aligned along the primary axis thereof, adjacent a hemispherical
 level vial for defining a level plane. This level may be part of a
 magnetic compass assembly, imbedded in the dial cover lens thereof, and
 may include concentric scribes or markings indicating the slope. An
 adjustable azimuth ring surrounding the lens vial then assists in defining
 the magnetic direction of the slope, the ring extending into two opposed
 lateral recesses formed in the sides of the body for manipulative
 convenience.
 To align the inventive sighting assembly against the exterior surface of a
 pipe bend segment the arm may be provided with a thumb screw affixed
 forward and rear bracket selectively securable along the length of the arm
 edge, each deploying a corresponding vertically spaced pair of contact
 points for contacting the measured surface. The spacing between the
 brackets together with the dimension of the contact points combine to
 define a measuring cage selected to match the pipe diameter and bend
 radius, thereby providing a convenient set of contacts for aligning the
 sighting assembly on the pipe. When the protractor arm is collapsed into
 the profile of the body these brackets are then received in the recesses
 on the sides of the compass azimuth ring.
 A second, even more rugged, sighting assembly may be provided with two
 orthogonal level vials along and across the longitudinal dimension of the
 body, again in visual proximity with the magnetic compass. The compass is
 once more aligned between the lateral recesses to expose the edge of the
 azimuth ring. In this implementation the protractor arm may be useful
 without the brackets, functioning as an alignment guide along the pipe
 exterior.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 As shown in FIGS. 1-4, the inventive sighting assembly, generally
 designated by the numeral 10, includes a rectangular body 11 defined by a
 forward end 12 and a rear end 13. A pivoted arm 15, in the form of a
 straight edge, pivots from a frictional pivot 16 proximate the forward end
 12 of the body 11, subjacent the lower surface thereof. A pair of sliding
 bracket posts 21 and 22 are each provided with a lateral recess 23 and 24
 conformed to receive the exterior edge of arm 15 and are therefore
 slidably engaged thereto. Each post 21 and 22 may be provided with a
 corresponding thumb screw 25 and 26 extendable into the lateral recess,
 useful in securing the posts along the arm edge. Each post 21 and 22,
 moreover, may include a corresponding upper and lower measurement pin
 21-u, 21-l, 22-u and 22-l, forming the corners of a virtual measurement
 surface reference which can then be applied to the exterior of a pipe
 elbow E or a straight pipe segment (not shown).
 One will note that the four-cornered reference plane defined by the
 measurement pins 21-u through 22-1is of necessity symmetrical about the
 plane of arm 15. Accordingly when placed to the exterior of a convex outer
 surface of the elbow E this measurement cage will also tend to `find` the
 plane of symmetry of the elbow. This virtual measurement cage, moreover,
 can be adapted to larger or smaller elbows by the sliding separation of
 the posts along the arm.
 Body 11, in turn, may be provided with a compass assembly 31 imbedded
 generally rearwardly therein, defined by a magnetic compass needle 32
 covered by a hemispherical lens structure 33 with a central cavity 34
 partly filled with fluid F to form a level. The exterior of the lens
 structure 33 may be scribed with concentric scribe rings 36 and 37
 corresponding, for example, the deviation of the level meniscus M from
 horizontal to 1/8 or 1/4 inch to the foot slope. An adjustable azimuth
 ring 38 is then engaged to surround the compass assembly, ring 38 being of
 a diameter slightly larger than the local width of the body, as reduced in
 dimension by a pair of opposed lateral cutouts 55 to expose the ring for
 manipulative convenience.
 A laser pointer 41 may be received within a longitudinal drilling 41a
 extending through the body 11 to emit through end 12 a beam B to a target
 T in the desired direction of drainage. This beam arrangement is aligned
 relative the pipe segment by the pivoted arm 15 with the posts 21 and 22
 placed relatively far rearwardly along the arm in order that the beam path
 be sufficiently removed from the elbow end for all realistic slope
 measurements and to separate as far as practical the magnetic compass from
 any ferrous mass. The forward end 12, moreover, may be provided with a
 protractor surface 52 against which an end extension of arm 15 is
 displayed, thereby providing a visual indication of the limits of
 practical slope measurement.
 It should be noted that posts 21 and 22 may engage either one of the edges
 that define arm 15, and the assembly is therefore useful for opposite pipe
 bends, achieving universal application in laying out pipe runs. This
 reversible function is further accommodated by the opposed cutouts 55 into
 which the posts 21 and 22 are received once the device is collapsed.
 Thus the foregoing assembly may be rendered collapsible for convenient
 portability by way of cutouts 55 in the lateral edges of the body, which
 also serve to expose the azimuth ring. These same cutouts 55 may be
 covered with pivoted covers 56 to shield the respective pins during
 transport. In this manner a simple, rugged and inexpensive sighting
 assembly is provided which is particularly useful in pipe work.
 By reference to FIGS. 5 and 6, an even more rugged and simple sighting
 assembly is provided, generally designated by the numeral 110. Like
 numbered parts functioning in like manner to that previously described,
 assembly 110 once again includes a body 11 provided with a pivoted arm 15
 in the form of a straight edge pivoted from the end 12, and a compass
 assembly 131 again received proximate the other end exposing an azimuth
 ring 38 into opposed cutouts 55. In distinction to the compass assembly
 31, the instant assembly 131 does not include the leveling bubble in the
 lens thereof, the body 11 instead including,two orthogonal level vials 141
 and 142, respectively across and along its longitudinal dimension.
 To maximize viewing convenience level vial 142 may be bedded in a
 longitudinal edge of body 11, generally in the middle of the length
 thereof, and is thus exposed for viewing from several directions.
 Similarly, vial 141 may be exposed through the surfaces of body 11 and
 through the opposite edge. This arrangement allows for quickly deployed
 sighting device with minimal adjustment and reference points,
 Within the range of the above described embodiments and examples it is both
 useful and advantageous to omit the posts 21 and 22 while retaining the
 structure of compass assembly 31, or to combine the structure of the level
 vials 141 and 142 with compass assembly 131 while also retaining the posts
 21 and 22 on arm 15. In both examples, moreover, the removal and
 replacement of the laser pointer 41, or any of its batteries (not shown)
 from the bore 41a may be facilitated by a threaded plug 48 closing the
 bore opening in the end 13 fixed by a set screw 49. In this manner a
 convenient, rugged and inexpensive sighting assembly is devised whin in
 its several forms can achieve various levels of precision. Of course,
 non-ferrous material structures are useful herein to limit any unwanted
 influence on the magnetic compass, while the arm deployment maximizes
 separation from any ferrous pipe segments.
 Obviously many modifications and variations of the above teachings may be
 carried out without departing from the spirit of the present invention. It
 is therefore intended that the scope of the invention be determined solely
 by the claims appended hereto.