Abstract:
The present invention relates to an apparatus for designating and marking an area. The apparatus consists of a hanger for suspension to a string line. Attached to this hanger is a brace which supports a pivoting laser source. This laser source may be rotated to any desired angle, so that the laser source projects its beam to a desired location for use in marking this location. The desired angle is designated with a compass plate and pointer.

Description:
CROSS REFERENCES TO RELATED APPLICATION 
     None. 
     BACKGROUND OF THE INVENTION 
     a. Field of the Invention 
     The invention relates to devices which make measurements and measure angles for construction. In particular, the invention relates to devices which use a laser beam mounted onto a string line to aid in construction layouts. 
     b. Description of the Prior Art 
     The prior art contains multiple devices which use a laser beam to aid in construction layouts. Many of these devices are used as levels which project a laser beam in a horizontal plane. U.S. Pat. No. 4,221,483 to Rando uses a complex level system to emit a horizontal laser which is detected by an electronic detector. Many of these devices are confined to mounting on a tripod or other platforms. Other devices emit laser beams perpendicular to a given plane. U.S. Pat. No. 5,594,993 to Tager emits such a beam from a hand held device and can substitute for a string line. 
     The limitations of a required detector, a fixed height platform, and a perpendicular emitted laser beam make it desirable to have an invention which overcomes these limitations. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide an apparatus which does not require a detector, can be used at any desired height, and can designate angles for laying out and marking a construction site. The present invention accomplishes this objective by providing hangers and a brace to support a laser unit from a string line fixed between two reference points, using a cooperating compass plate and compass pointer so that an angle relative to the line formed by the string can be selected for the emitted laser. 
     There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. Additional benefits and advantages of the present invention will become apparent in those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientist, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and the objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
     FIG. 1 is a top view of the present invention. 
     FIG. 2 is a front view of the present invention. 
     FIG. 3 is a bottom view of the present invention. 
     FIG. 4 is a side view of the present invention. 
     FIG. 5 is a detail view in cross section of the rotation support means. 
     FIG. 6 is a perspective view of the locking lever. 
     FIG. 7 is a schematic representation of the present invention in operation. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention comprises an adjustable laser string square  10  as generally shown in FIGS. 1 through 4. The adjustable laser string square  10  is supported from a string line  12  strung tautly between a first point  14  and a second point  16 . As shown in FIG. 1, a first hanger  18  and a second hanger  20  support the adjustable laser string square  10  from the string line  12 . Depending from the first hanger  18  is a first support shaft  22 ; similarly, a second support shaft  24  depends from the second hanger  20 . As shown in FIG. 7, the first and second attachment means,  26  and  28 , attach the first and second support shafts,  22  and  24 , to a compass plate  30 . The compass plate  30  has angular markings  31  thereon ranging from 0° to 90°. A laser unit  32  is supported from the compass plate  30 . The laser unit  32  is housed in a laser unit housing  34 . A battery compartment  35  is disposed on a lower surface of the laser unit housing  34 . As shown in FIG. 4, the side view, the laser unit housing  34  also incorporates an on/off switch  36  and a power level switch  38 . A laser source  40  is disposed at an end of the laser unit housing  34 . 
     FIGS. 2,  4 ,  5  and  6  illustrate a rotational support means for supporting the laser string square  10  from the compass plate  30  in a rotatable manner. The laser unit  32  depends from a support shaft  42 . The support shaft  42  depends from the compass plate  30  as shown in FIG.  4 . At an upper end of the support shaft  42  is a wing nut  44 . The wing nut  44  is used to secure the compass pointer  46 . An upper nut  48  provides the actual support for the support shaft  42 . Disposed underneath the upper nut  48  is an upper washer  50 . Preferably, the upper washer  50  is composed of a plastic or rubbery material, preferably Teflon®. The purpose of the upper nut  48  is to allow rotation of the support shaft  42  relative to the compass plate  30 , while providing a gripping means should a user desire to fix the compass pointer  46  in place. Below the compass plate  30  is a lower washer  52  and a lower nut  54 . A locking lever  56  is disposed adjacent to the lower nut  54  and lower washer  52 . The locking lever  56  is attached via a pivot point  58 . A straight portion  62  extends outwardly so that a thumb grip portion  60  extends beyond the edge of the compass plate  30 . Fastened onto the straight portion  62  are a pair of angular friction plates  64 . A center end of the angular friction plates  64  is disposed between the lower washer  52  and the compass plate  30 . When biased toward the support shaft  42 , the angular friction plates  64  tend to fix the support shaft  42  into place so that it does not rotate. The locking lever  56  is fastened to the compass plate  30  via a pivot bolt  66 . 
     As shown in FIG. 1 the laser string square  10  may also incorporate a bubble level  68  or the like. This allows a user to determine whether a point indicated by the laser beam is on a horizontal plane with the laser unit  32 . It is well known in the prior art to provide an electronic level means with a digital readout. 
     As shown, the compass pointer  46  and the compass plate  30  comprise an angle selector means. Alternatively, so that angles can be precisely measured, the support shaft  42  may employ a mechanism so that the compass pointer  46  clicks into an angle, or in the alternative, allows smooth rotation into any angle measurement. Additionally, a digital readout may be employed so that an angle may be precisely found. Also, configurations for the angle selector means are also possible, given the foregoing description. 
     OPERATION OF APPARATUS 
     Before operating the apparatus, it is important to calibrate it to ensure that it is calibrated properly. The calibration device is very simple. The laser unit  32  is turned so that the emitted laser points at either the first point  14  or the second point  16 . The wing nut  44  is then loosened. The compass pointer  46  is aligned with the angular markings  31  on the compass plate  30  so that it is at the appropriate zero marking. The compass pointer  46  and the compass plate  30  cooperate to form the angle selector means. The laser unit  32  is then rotated 180° to ensure that when the emitted laser is pointing at the opposite point (again, either the first point  14  or the second point  16 ) that the compass pointer  46  is then pointing at the corresponding zero degree reading. 
     Once the device has been calibrated, it is ready to be used. In operation, the apparatus is first suspended from a string line defining a straight line between a first point  14  and a second point  16 . The adjustable laser string square  10  is then moved to the appropriate starting point for the desired measurement. Once located at the desired starting point, the laser unit  32  is turned so that the emitted laser beam is at the desired angle as indicated on the compass plate  30  by the compass pointer  46 . A user then moves outwardly the desired radial distance from the adjustable laser string square  10 , and, using an opaque or translucent surface, identifies the line made by the laser beam. The point at the desired distance and the desired angle, is then marked by a stake or other traditional means of marking a point. If it is desired to mark still another point from the point just marked, a new string line is set up along the line just marked, then the adjustable laser string square  10  is moved over the point just marked, to be used to find the new point. Once the adjustable laser string square  10  has been moved, it is ready to be used again. 
     As shown in FIG. 7, which is a schematic representation of the present invention in operation, the adjustable laser string square  10  is supported at a point between the first point  14  and the second point  16 . The distance from the adjustable laser string square  10  to the first point  14  is length  70   a . Length  70   b  is the distance between the adjustable laser string square  10  and a third point  72 . The distance  70   c  between the adjustable laser string square  10  and a fourth point  74  is also the same. FIG. 7 illustrates how the present invention may be used to mark points to make a hexagonal semi-circle. To make a complete hexagon, the mirror image of the point shown in FIG. 7 would be marked using the adjustable laser string square  10 .