Plumb point locator

March 13, 1951

2,545,321

S. TUMMINELLO

PLUMB POINT LOCATOR

Filed Sept. 4, 1947

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FIG.3.

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FIG.4.

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INVENTOR;

Sam TUMMINELLO,

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ATTORNEY.

Patented Mar. 13, 1951

2,545,321

UNITED STATES PATENT OFFICE

2,545,321

FLUME POINT LOCATOR

Sam Tumminello, St.'E0uis, Mo.

Application September 4,1947,Serial No. 772^37

Claims.

This//ih'veritidn -relates to plumb point locators, •and mote /particularly to improved devices for establishing with geometric exactness, the point Of-intersection tof a plumb line with a horizontal surface such as a ceiling.

•Under many conditions in the building indus'tries and trades, it Is highly desirable for structural reasons, as Well as for reasons of appearance of vertical building elements, whether interior tor exterior, to be sure -that such structures 'are erected with exactly vertical axes or along truly vertical planes. Heretofore, as far as is /known to this applicant, there has been no device available to the trade, nor any susceptible of ready production, of such nature as to enable an exact indication of apluffib point, for example, on a ceiling or like horizontal surface. Usually the ^!upper end tof a plumb line is supported by the thumb Or other digit, arid the determination of the exact point where the axis of such line intersects the 'surface is subject to the personal equation, hence to considerable error which is likely to be aggravated with increase in the vertical span between the floor and a ceiling element or the like. The present invention accordingly, has, as its primary objective, the attainment of a small low-cost device to obviate errors in the determination and indication Of plumb points, as hereinafter defined.

Yet another object tof the invention is attained in a low-cost instrument for the noted purpose, which need be of no great size, which may easily be carried in the pocket or tool kit of the user, and Which is practically indestructible in nature.

A Still further object tof the invention is attainable in a device which serves the dual purposes of a plumb line holder, and of an instru? ment for enabling, with suitable marking or scribing, a geometric location of a plumb point or plumb line axis.

The foregoing and many other objects will become more apparent from the following detailed description of a presently preferred embodiment of the invention, particularly when considered ih connection With the accompanying drawing, in which:

Fig. 1 is an isometric view of a plumb line attached to the improved locator, arid showing one manner of its usage:

Fig. 2 is a top or plan view of the locator, somewhat enlarged;

Fig. 3 is a side of edge elevation of the locator, and

Fig. 4 is a bottom plah view thereof.

The term “plumb line” as herein employed. Has (CI. 33—75) ·

reference to the Well-known combination Of plumb bob such as PB,to which is attached a flexible cord, wire, or like tension member PL·, and may be of any of the well-known types emS ployed by artisans, engineers, or others concerned with the establishment of a true, vertical relation of the various elements of building or other structures. The term “plumb point” as herein employed is utilized in the sense of a point of 10 intersection of the plumb line, as an intangible, as produced vertically, With a ceiling or similar horizontal or approximately horizontal element above or below the line,

Referring now by characters of reference to the drawing, a conveniently produced and lowcost embodiment tof the locator is a body in the nature of a block prepared by molding or machining to exhibit the characteristics and features now to be described. The article may be produced of a single piece of -metal, usually of aluminum, magnesium or other metals or alloys characterized by light weight, and of non-corroding character. Alternately, a highly satisfactory low cost article may be produced as by compression molding or otherwise, of any of the numerous suitable plastic materials available to the trade for similar purposes. In such case the molding dies are carefully and accurately formed so as to impart a similar accuracy to the molded article.

^ΰ The preferred form of body or block includes a central portion 10, shown as circular in plan and modified by a pair of opposite diametral extensions I I and 12. Each such extension appears, _g5 in plan, as a frustrate triangular or quasi-triangular member, characterized by an outer base 13 and converging sides 14 arid 15, the corresponding elements being similarly numbered on the two opposite extensions.

₄₀ The thickness or depthwise dimension of the body is a matter of choice, but should be sufficient to make for ease in utilization of the edges resulting from the sides 14 and 15, as straight edges for and in marking dr scoring, as will later appear. With this in view, a depth or thickness of the block of the order of oiie-half to threequarters ihcli IS preferred. Each of the faces, iriclhdirig h top frioe 16 arid a bottom face 17, is of a flat or planar Characteristic, so that, as will later appear, the device may be readily shifted as by sliding ffidveirierit airing a horizontal surface, for example that of a plastered ceiling. Exactly normal, within reasonable limits of ease tof production, to the surfaces 16 arid 17 are the faces located at 13; 14 arid 15. it will fuftliei2,545,321 appear from the dotted lines indicating extensions of the faces 14 and 15, that each plane includes the axis and exact center of a vertical cord channel or bore 20, which is, by preference and as shown, located in the exact center, each, way, of the block.

It will now have appeared that the plane of faces or facets 14, and that including faces 15, intersect in the exact center of the plumb line as definitely located thereby. By preference, although not of necessity, the two base portions, edges and faces 13 are parallel, and to each, the plane 14—14 and likewise the plane 15—15 bear a 45 degree relation.

As a convenience and facility for introduction of the cord of the plumb line fully into channel 20, the central body portion 10 is provided with a radial slot 21, which extends from the periphery inwardly to and into the channel 20, and width of slot 21 being by preference the same as the diameter of the channel or bore 20, were the latter fully circular in section. As will now be observed, the slot 21 permits lateral application of the locator to and over the plumb line and, otherwise stated, enables the lateral insertion of the plumb line to its seat as the locator is held stationary.

As making for further convenience in usage Of the device, it is a preference to provide as undercut from the face 16, a recess 22 extended radially of the circular portion 10. The recess 22 extends outwardly from the open end of channel 20 to the periphery or perimeter of the center part of the body. The width and depth of recess 22 is such as fully to receive the unused or inactive extension of the plumb line, and to permit the face 16 to be held flat against the ceiling or like surface without causing the locator to rock upon the excess part of the line. A similar groove or recess 23 is undercut from the opposite face 17 of the body block. The grooves 22 and 23 may be used alternately, but it has been found highly desirable to extend the excess line from channel 20 through recess 22 thence downwardly and into recess 23, the remaining end of the line being temporarily attached as by a clip (not shown) to that part of the active line depending from channel 20. Thus the device will serve as a line holder or support, as well as a plumb point locator.

It will have been observed that, while it is advisable that the planes 14—14 and 15—15 intersect in and include the axis of channel 20, the relation between the planes is not critically the order of 90 degrees. It is, of course, advisable that the angle subtended be uniform on the opposite sides of the center point or axis of the device. The underlying feature of the structure is that a pair of straight edges be so located that when a line is scribed along each, there will be enabled a geometric establishment of .a point' of intersection of the line or the cord axis with a surface at a right angle thereto for example a ceiling.

The manner of usage of the locator is thought now to have become fully apparent, but there may be included for completeness, a typical example of usage: Assume that it be required to erect vn interior partition. It is of course desirable as good engineering practice, sound structure and good appearance, to be assured of its exactly vertical Characteristic. A center or bounding line is scribed or marked on the floor. Near one end of the proposed partition the locator, with the determined length of plumb line depending therefrom, is placed against the ceiling, with an end portion of the cord or line occupying channel 20. The locator is then slidably moved over a portion of the ceiling in a direction transversely of the proposed partition until the bob point falls directly over the floor line. With the locator now held in position, markings are applied to the ceiling or other adjacent surface along at least a pair of the straight edges or facet portions 14 and 15, and preferably along each of such facets. The locator is then removed and lines 14—14 completed, then similarly the lines 15—15. The now continuous lines 14 and 15 will intersect in the exact center or axis of the cord or line occupying channel 20. A single such determination will locate the center of a columnar support, but if a structure of some linear extent, such as a partition be contemplated, a series of such operations are conducted, and the full line when thus established, is exactly parallel to and directly vertically above the lower line.

It should be noted that the device is useful as an aid in extending a vertical line to determine plumb points in or on either a subjacent element such as a floor, or in a superjacent structure such as a ceiling, if either of such points be initially known. If, for example, the ceiling line or point is established, it will now be observed from the foregoing example that by using the locator in one or a series of positions at floor level, and by locating the bob point directly above the top opening of the channel 20, the floor points may accurately be determined.

The foregoing examples are only a few of the many applications of the locator, from which it will appear that the several objects above stated and implied, are fully realized. Many of the terms used herein, such as “floor” and “ceiling” are not to be understood as restrictive of fields of usage. Furthermore, although the invention has been described by particularized reference to a single selected embodiment, the specific nature of the description should not be taken as limiting the scope of the claims hereunto appended, in view of the many possible structural variants.