US2245901A - Mounting for surveyor's targets - Google Patents

Description

June 17, 1941. I CHASKIN 2,245,901

MOUNTING FOR SURVEYORS TARGETS Filed Sept. 26, 1959 1 /W INVENTOR. jihraZzZ 671 f /J/iflib' A ATTORNEY Patented June 17, 1941 UNH'EED STATES PATENT GFFICE 2,245,901 MOUNTING FOR SURVEYORS TARGETS Harold Chaskin, New York, N. Y.

Application September 26, 1939, Serial No. 296,561

1 Claim.

This invention relates to a target used in surveying, especially in cities, and has for its object to provide an improved target capable of being correctly positioned in a shorttime and with little effort.

Another object has been to provide a target mounting so that several measuring or transit parties may work toward or away from it at the same time.

In surveying in urban centers for piping, subways, and a multitude of purposes, it has been often the practice to use a rigid target mounted on a tripod but positioned over some precise mark on the ground by means of a plumb-line. On windy days it is difiicult to get the plumb exactly in position. Sometimes several men have had to stand around the plumb-line with their coats open in an effort to shield it from the wind. Under this invention these disadvantages have been eliminated.

Referring to the drawing- Fig. 1 shows one embodiment of this invention.

Fig. 2 is a detail of the supporting rod which is held by the tripod.

Fig. 3 shows the top of the tripod.

Some conventional type target I is supported on the rigid rod II which has a lower extension portion i2 reaching to adjacent a mark l3 on the ground over which the target is to be accurately alined. The legs of the tripod M are of conventional form and support the target and its rod II. The lower end I6 of the rod H is separable and pointed as shown in Fig. 2 to facilitate correctly and quickly placing the pointed end over the mark it. The portion [1 of the rod which is clamped by the top of the tripod is knurled or otherwise suitably roughened to enable the rod to be securely held. A level I is preferably afiixed to the rod and secured by the screw threads [8 shown at the end of the separable portion containing the level. This level is of a well known type usually circular so that the bubble when in the center indicates that the rod to which it is attached is vertical.

Another target I9 may be located either above or below the first target and is supported so as to be displaced at any desired angle in such a position so that one or more measuring or transit parties may work toward or from each target. As shown in Fig. 1 the second target if! is located at right angles to the first target. It will be understood that more than two targets may be used and any one of them may be located at any desired horizontal angle with respect to another and held in such desired position preferably by means of a clamp and wing nut not shown though, of course, if desired a good friction fit may suffice instead.

As shown in Fig. 3 the legs M of the tripod are connected to a head 29 which carries an upstanding threaded flange 2| as is customary for tripods used to support a transit, level and other instruments. Screwed over the flange 2| is a base 22 of the removable support for the rod II.

This support comprises a tubular guide portion 23 through which the tube is movable with a sliding fit so that the pointed end I6 may be brought closely over the ground mark l3 regardless of the height of this mark or the height of the tripod. A clamp 24 holds the rod l I securely supported in the tubular guide. This clamp is provided with a customary wing nut 25 or other suitable means for loosening or tightening the clamp. Leveling screws 26, preferably four in number as is usual, are provided between extensions from the tubular guide 23 and the base 22 of the removable support, so that the tubular guide may be leveled irrespective of whether or not the base 22 is level. Between the base portion 22 and the tubular guide .23 is a connection 21 which allows limited tilting of the tubular guide with respect to the base and also allows limited horizontal motion in any direction between the guide 23 and the base portion 22, so that the lower end iii of the rod may be shifted in a horizontal plane to bring it directly over the ground mark I3.

Among the advantages of this invention maybe mentioned the ease of setting up the target over a mark on a windy day. The lateral projections shown for the tubular guide 23 may or may not be provided with bubble tubes arranged at right angles to one another to assist in leveling. In other words, the leveling may be done entirely by means of the level [5, or the additional level tubes referred to may be used, or such additional tubes may take the place of and render the level l5 unnecessary especially when the rod has a fairly snug fit within the tubular guide 23. The removable support for the target rod difiers from the removable support ordinarily attached to a tripod by reason of the central hole through which the rigid rod I l projects.

I claim:

The combination with a tripod having a head, of a surveyors target, a rod on which the target is carried, a support carried by said head for said rod, an alined rigid axial projection of said rod having a pointed end extending below said support to adjacent the ground for cooperation with a marker on the ground, said head having a perforation therein through which said rod projection passes, and means located between said head and support for adjusting said rod, projection, and target into vertical position above said marker.

HAROLD CHASKIN.

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