US2618856A - Compass and charting device - Google Patents

Description

Nov. 25, 1952 Filed July 19 1951 R. E. SWEET COMPASS AND CHARTING DEVICE 2 SHEETS-SHEET l INVENTOR.

ZZZ/YI Vw f Nov. 25, 1952 R. E. SWEET COMPASS AND CHARTING DEVICE 2 SHEETS-SHEET 2 Filed July 19, 1951 4 INVENTOR.

faiev'fi'pY n ee" ATTORNEYS Patented Nov. 25, 1952 UNITED STATES F EET QFFICE 2 Claims.

My invention relates generally to mapping or charting devices and more particularly to a combined directional compass and mapping board or the like.

An important object of my invention is the provision of a mapping or charting device which will enable a relatively unskilled person to plot a map of a given area.

Another object of my invention is the provision of a compass and mapping device having a mapping surface capable of receiving delineations and from which said delineations may be easily erased.

A still further object of my invention is the provision of a device, as set forth, which may be manipulated to direct the operator to his starting point from any part of a boundary at which he may be positioned.

Another object of my invention is the provision of a device, as set forth, which is very compact so as to occupy a minimum of space when carried about or when in storage.

Still another object of my invention is the provision of a compass and charting device of the above type which is simple and inexpensive to produce, which is efiicient in operation, and. which is rugged in construction and durable in use.

Other highly important objects and advantages of my invention will become apparent from the following detailed specification, appended claims, and attached drawings.

Referring to the drawings, which illustrate the invention, and in which like reference numerals indicate like parts throughout the several views:

Fig. 1 is a View in plan of my novel compass and mapping device;

Fig. 2 is an axial section taken substantially on the line 2-2 of Fig. 1;

Fig. 3 is a view partly in section and partly in plan taken on the line 33 of Fig. 2, some parts being broken away;

Fig. 4 is a view corresponding substantially to Fig. 1, but showing a difl'erent position of some of the parts; and

Fig. 5 is a View similar to Fig. 4, but showing a still different position of some of the parts.

Referring with greater detail to the drawings, it will be seen that my mapping device comprises a fiat generally circular base plate I provided with a radially outwardly projecting handle member 2 formed integrally therewith. The base plate I may be made from any suitable material such as wood, metal, or synthetic resins, and is formed with opposed straight side edges 3.

A circular chart 4 is located in the center of the base plate I and is provided with equidistantly spaced parallel lines 5 which are crossed at right angles by spaced parallel lines 5, the spacing of which is equal to the spacing between the lines 5 whereby to cooperate therewith to form squares of equal size over the area of the chart i. The chart 4 may be made in any suitable manner such as imprinting the same on the base plate but, preferably and as shown, is in the nature of a separate layer of thin material such as printed paper or the like anchored to the base plate by a suitable adhesive. The chart 4 is further imprinted with an equidistantly spaced plurality of concentric circular lines I for a purpose which will hereinafter become apparent and a homing line 8 extends radially outwardly from the center of the chart 4 toward the handle memher 2 of the base plate I. As shown in Figs. 1 and 3 to 5 inclusive, the base plate I and the chart 4 are imprinted with aligned arrow heads or triangular pointers 9 and Hi respectively, said pointers being aligned with the homing line 8.

The base plate i is provided with an aperture in which is received a shaft in the nature of an anchoring rivet or the like H that extends upwardly through the center of the chart l and the center of an overlying circular protractor element [2. Said protractor element I2 is journalled for rotation on the rivet I l and comprises an annular peripheral portion i3 and a transparent central portion is. The annular portion I3 is of greater thickness than the central transparent portion it whereby to provide a downwardly opening recess E5 in which is contained the chart 4, see Fig. 2. Portion I3 is preferably opaque so as to cause the letters and numerals thereon to stand out better. Said annular portion is is imprinted or marked with graduations indicating circular degrees numbering con secutively from a zero degree marking, and with letters N, E, S and W, indicating the cardinal points of the compass. With particular reference to Fig. 1, it will be seen that the character N designating north is coincident with the zero marking of the protractor [2.

The central mapping portion M of the protractor i2 presents a flat top mapping surface which is capable of receiving delineations or suitable markings from ordinary lead pencils or the like, and from which said delineations may be easily eradicated by using an eraser, damp cloth, or the like. It i not essential that the mapping portion M be absolutely transparent. It is only necessary to make the same sufficiently transparent so that the crossed lines and 6 and the circular lines I of the chart 4 be visible therethrough. It is preferable that the mapping surface l2 be provided with sufficient roughness or tooth to enable the same to be easily marked with ordinary pencil. However, the mapping surface is not roughened to a point where the chart 4 is not easily discernible therethrough.

The protractor I2 is provided with an integrally formed tongue or the like I6 which projects radially outwardly from the peripheral edge thereof diametrically opposite the zero or North marking. Preferably, and as shown, the tongue I6 terminates in a magnetic compass I'I comprising a casing I8 and a magnetic needle or pointer I9 pivotally mounted therein, as indicated at 29. The casing I8 is provided with a transparent cover 2| having etched or otherwise imprinted thereon a straight line or arrow 22 which lies in a plane containing the pivot axes of the pointer I9 and the protractor I 2. lhis arrangement provides that the line or arrow 22 will be directed through the axis i of the pivot shaft i I irrespective of the position of the protractor element I2 with respect to the base vI about the pivot axis of the protractor I2. Al-

though the casing I8 of the compass I T is shown :as being integrally formed with the tongue it, it will be appreciated that said casing may be ;a separate element anchored to the tongue by :any suitable means. Also, if desired, the compass may be filled with suitable liquid, as indicated at A.

In the utilization of my invention in mapping :a predetermined area, the shaft or rivet II comprises the starting or home point. The sides '01 each square formed by the crossed lines 5 and 5 represent a predetermined number of feet, yards, or paces, depending upon the extent of the area to be mapped. For example, each line 5, between adjacent cross lines 6, may represent a distance of 180 paces. When it is desired to plot a predetermined area, the protractor I2 is held level with the N or zero marking directed to magnetic north, see Fig. 4. With the protractor in this position, it will be seen that the compass pointer i9 is aligned with the line or arrow 22. The operator then rotates the base plate I with respect to the protractor 32 until the aligned arrow heads 9 and i8 point in the direction of one of the proposed boundary lines of the area to be mapped, in this case a northeasterly direction or approximately 45. The operator then paces off the required distance, drawing a straight line, indicated by the broken line 23 in Fig. 4. In the event that a predetermined distance between adjacent lines 5 and 6 is 100 yards, the in dicated length of the boundary 23 is eleven hundred paces. When the required distance has been paced off and marked on protractor I2, the base plate I is rotated relative to the protractor I2, the protractor still being directed toward magnetic north, until the aligned arrows 9 and I B are pointed in the direction of the second boundary pm the mapping portion Id of the protractor I2.

My improved device may be utilized to enable the operator to find his way directly to the starting point without retracing the boundaries laid out on the mapping surface by merely swinging the base plate I with respect to the protractor until the homing line intersects the point of the boundary at which the operator is located. The homing line 8 and the arrows 9 and IE] will then bedirected toward the starting point. This featureof the invention enables the user to quickly find his way back to the starting point in the event he becomes confused duringthe mapping operation.

The concentric lines 1 are utilized to define circular areas of progressively greater extent and are of value in the teaching of map making activties to boys outdoor organizations such as the Boy Scouts and the like. For example, a beginner would be confined to the area indicated by the inner circular line and, as progress is made in his map making activities, the operator or student will be permitted to work in areas defined by the larger circles. Upon completion of the boundary marking operation and return to the starting point, the delineations made upon the mapping portion I4 of the protractor I2 may be traced upon tracing paper or the like and the delineations erased from the mapping surface of the protractor whereupon the same is available for use by another operator or for another plotting operation.

It should be obvious that the compass may be used in a normal manner to indicate the direction of travel generally and not only for the purpose of map making and the like. A direction of travel is determined by aligning the arrow or line 22 and the homing line 8 with the compass needle I9 and turning the base plate I with respect thereto so that the aligned arrows 9 and II] are pointed in the direction of travel. This arrangement provides a clear and exact indication of the direction of travel.

My invention has been thoroughly tested and found to be completely satisfactory for the accomplishment of the objectives set forth; and, while I have shown and described a preferred embodiment of my novel compass and charting device, it will be understood that the same is capable of modification and that modification may be made without departure from the spirit and scope of the invention, as defined in the claims.

What I claim is:

l. A compass and charting device comprising a base plate, a chart on the central portion of said base plate, a pointer adjacent the peripheral edge portion of said base plate in radially outwardly spaced relation to said chart, a handle projecting radially outwardly of said base plate in diametrically opposed relation to said pointer, a circular protractor element overlying said chart and including an opaque annular peripheral portion extending circumferentially between said chart and pointer and a transparent central mappin portion overlying the area of the chart circumscribed by said annular portion, means coaxial with said protractor element for mounting said element to the center of said chart for rotary movements with respect thereto, a tongue projecting radially outwardly from the edge portion of the protractor element, and a magnetic compass rigidly mounted on said tongue, said compass including a casin having a transparent cover element and a pivoted magnetic pointer in said casing underlying said cover element, said cover element being marked with a straight line lying in a plane containing the ivot axes of said magnetic pointer and said protractor, the handle member on said base plate underlying said tongue when the pointer on said base plate is moved to register with said plane in dlametlically pposed relationship to said comp the ppi g portion of said protractor havitng a fiat top surface capable of receiving delinea- 2. A compass and charting device comprising a base plate, a chart on the central portion of said base plate, a pointer adjacent the peripheral edge portion of said base plate in radially outwardly spaced relation to said chart, ahandle projecting radially outwardly of said base plate in diametrically opposed relation to said pointer, a circular protractor element overlying said chart and including an annular peripheral portion extending circumferentially between said chart and pointer and a transparent central mapping portion overlying the area of the chart circumscribed by said annular portion, means coaxial with said protractor element for mounting said element to the center of said chart for rotary movements with respect thereto, a tongue projecting radially outwardly from the edge portion of the protractor element, and a magnetic compass rigidly mounted on said tongue, said compass including a casing having a transparent cover element and a pivoted magnetic pointer in said casing underlying said cover element, said cover element being marked with a straight line lying in a plane containing the pivot axes of said magnetic pointer and said protractor, the handle member on said base plate REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,008,934 White Nov. 14, 1911 2,007,986 Sprague July 16, 1935 2,407,893 Meyer Sept. 17, 1946 2,485,674 Suiter Oct. 25, 1949 2,527,691 Watson Oct. 31, 1950 FOREIGN PATENTS Number Country Date 104,824 Sweden June 23, 1942

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