US3205581A

US3205581A - Adjustable sundial

Info

Publication number: US3205581A
Application number: US286409A
Authority: US
Inventors: Ann M Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-06-07
Filing date: 1963-06-07
Publication date: 1965-09-14
Anticipated expiration: 1982-09-14

Description

V Sept. 14, 1965 A. M. MOORE ADJUSTABLE SUNDIAL 2, Sheets-Sheet 1 Filed June 7, 1963 INVEN TOR. aim? M. Moore ATTORNEY Sept. 14, 1965 A. M. MOORE ADJUSTABLE SUNDIAL Filed June 7, 1963 2 Sheets-Sheet 2 INVENTOR.

47m .M. Moore BY Q ATTORNEY United States Patent 3,205,581 ADJUSTABLE SUNDIAL Ann M. Moore, Box 331, Granite Falls, N.C. Filed June 7, 1963, Ser. No. 286,409 1 Claim. '(Cl. 33-62) This invention relates to sundials, and is more particularly concerned with a portable decorative sundial that is adjustable to indicate the sun time in any latitude.

In the past, sundials have taken many forms. Some sundials have been made adjustable; but, these previous adjustable sundials have required many metal parts, making the sundial expensive and unattractive.

The sundial of the present invention comprises a face plate having a dial thereon. The face plate is pivotally connected to a mounting plate so that the angular disposition of the face plate with respect to the mounting plate can be varied.

A gnomon is supported by the face plate. The gnomon is in the form of a rod, and is slidably supported at one edge of the face plate and held by slidable means at the opposite edge 'of the face plate.

The present sundial therefore provides a dial that can be mounted and adjusted to face in the proper direction. The gnomon can be adjusted to indicate the sun time in any given latitude. The sundial is readily adaptable to be a wall dial, horizontal dial, or a dial disposed at any other angle.

These and other features and advantages of the present invention will become apparent from consideration of the following specification when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of one preferred embodiment of the present invention;

FIG. 2 is a side elevational view of the device shown in FIG. 1;

FIG. 3 is a top plan view;

FIG. 4 is a detail cross-sectional view of one of the gnomon supports; and,

FIG. 5 is a detail cross-sectional view of the other gnomon support.

In mounting a sundial to indicate sun time, the first principle is to fix the shadow-casting device, or gnomon, so that the edge of the gnomon which casts the shadow to be read is parallel to the axis of the earth. The dial on which the shadow is to be read must then be marked with indicia so located as to have the shadow of the gnomon fall across the proper indicium at the proper time.

Things on the earth are located substantially on a tangent to the earth, and the latitude of a given location gives the location of the tangent point with respect to the two poles of the earth. To locate the gnomon, therefore, it is necessary to make the angle of the gnomon equal to the angle of the latitude of the location.

For most practical purposes, if a dial face is to point toward the equator (i.e., face north in the Southern Hemisphere and south in the Northern Hemisphere) the dial can be substantially circular. A dial can of course be oriented in any way desired, as long as the dial is properly designed. The dial can be designed according to the known laws of gnomology; or, in the present day of accurate clocks, the various indicia can be placed empirically by the location of the shadow when a clock indicates a given time.

While the features of the present sundial allow it to be adapted with ease to any orientation, the device here presented is designed to face the equator, and is adapted to be mounted on a vertical wall, providing what is known as a wall dial.

3,205,581 Patented Sept. 14, 1965 ice Referring now to the drawings and to that embodiment here presented by way of illustration, the device includes a face plate 10 having a dial 11 thereon. The dial 11 can be applied in numerous ways; e.g., it can be painted on, etched, separate pieces can be attached, and numerous other methods can be used.

It is contemplated that the face 13 will be made of a plastic sheet or the like, with a frame 17 of wood or other convenient material. With such a construction, translucent or transparent material can be used for the face 13, and the dial can be so mounted that it can be read from the rear as well as the front, thus providing a kind of window dial.

The face plate 10 is secured to a mounting plate 12. One vertical edge of the face plate 10 is attached to the mounting plate 12 by hinges 14 so the face plate 10 can be disposed at various angles with respect to the mounting plate 12. It will be understood that the mounting plate 12 may be simply a frame, as here shown, or may be a full plate. A wall, as of a house, may serve as the mounting plate 12, with the hinges 14 attached directly to the wall.

The opposite vertical edge of the face plate 10 is provided with an adjustable lock 23. The lock 23 includes a bracket 16 secured to the mounting plate 12, and pivotally carrying a rod 15. The face plate 10 carries a bracket 18 which slidably receives the rod 15, and has a locking screw 19 to fix the rod 15 to the bracket 16.

Thus, the mounting plate 12 can be attached to a wall, and the face plate 10 can be rotated about the hinges 14 to face true south (or north in the Southern Hemisphere). The pivotal mounting of the rod 15 allows it to follow the angular motion of the face plate 10, and the locking screw 19 can lock the face plate 10 in any desired position by clamping the bracket 18 to the rod 15.

A magnetic compass 20 is carried by the lower edge of the face plate 10 to show the proper setting of the face plate 10. It will of course be realized that the dial 11 must be oriented according to geographic north rather than magnetic north; however, one must simply have the angle of declination of the particular locality (i.e., the angle between geographic north and magnetic north) in order to make the needed correction. The compass 20, therefore, simplifies the orientation of the sundial.

At the center 'of the lower edge of the face plate 10, and secured to the frame 17, there is a support rod 21. The support rod can be conveniently installed by inserting it into a hole in the frame 17 of the face plate 10. The support rod 21 is preferably perpendicular to face 13. It can be set at various angles; but, the dial is simplified if the angle for the gnomon is a linear relationship.

The support rod 21 slidably carries a support block 22. The support block 22 has a longitudinal hole 24 therein to receive the support rod 21 and a threaded, transverse hole 25 intersects the hole 24 to receive a locking screw 26. Thus, with the locking screw 26 loose, the support block 22 can slide freely along the support rod 21, but the screw 26 can be tightened to lock the support block 22 in any desired location.

The upper surface of the support block 22 has a recess 28 therein which receives the lower end 30 of the gnomon 29. It will be noticed in FIG. 5 that the recess 28 provides clearance on both sides of the gnomon 29. This clearance allows the block 22 to be moved along the support rod 21, while the gnomon 29 pivots about its opposite end, without binding in the recess 28.

The gnomon 29 is made of a round rod. The lower end 30 is rounded to seat properly in the recess 28 regardless of the angle of the gnomon 29 with respect to the block 22. The upper end 31 of the gnomon 29 has an enlarged portion 32 to limit the movement of i the gnomon 29.

The upper end 31 of the gnomon 29 is slidably held in an eye 34. A conventional screw eye is screwed into the top edge of theframe 17 of the face plate 10, and is fitted with a grommet 35. The grommet 35 fits tightly around the gnomon 29. The grommet 35 is preferably madeof a material having considerable deformability and a high coeflicient of friction, such as rubber,

the support block 22 along the support rod 21 until the angle a is correct. If desired, indicia may be placed along the rod 21 to indicate the position of the block 22 to give various angles. g

It is contemplated thatthe dial 11 would. be printed or otherwise placed on the face 13 at the time of manufacture; however, the user can do so if he wishes.

To calibrate the dial 11, the sundial is properly installed as described above. The noon mark is normally the first indicium to be placed. The simplest method is to note the location of the shadow. ofthe gnomon 29 on the face 13 when a clock indicates noon, Once the noon mark is established, asimilar procedure is followed to establish the remaining hour, marks from sunrise to sunset. I p p v r During a year, sun time varies from mean, time, or clock time, the two coinciding only four times during the year. This difference is only 16 minutes at; the maximum, which need not be considered for most purposes in reading a sundial. If a high degree of accuracy is desired, a

.1 4 standard chart may be used to show the correction required. 1

It will, of course, be realized that the device here presented is by way of illustration only, and is meant to be in no way restrictive. Therefore, numerous changes and modifications may be made and the full use of equivalents resorted to, without, departing from the spirit or scope of the invention as outlined in the appended claim.

A sundial including a mounting plate adapted to be attachedto a vertical wall, a face plate having oneedge thereof hingedly connected toone vertical edge of said mountingplate, an adjustment rod pivotally connected to the oppositetvertical edge of said mounting plate, a bracket on .the ,edge of, said face plate adjacent. said opposite.v vertical. edge ,of'said mounting plate, saidbracket slidably receiving vsaid adjustment rod, said. bracket having means for fixingysaid rod with respectto said bracket, an eye onthe top edge of said face plate, said eye having a grommet therein, a support rod .on the lower edgeof said face plate andperpendicular to said face plate, said support rod having a support block slidably mounted thereon, a gnornon comprising a rod, said gnomon being slidably received through said grommet insaid eye, one ,end of said, gnomon being received in a recess in said supportblock, and means for fixing said support block with respectto said support rod.

' v, References Cited bythe Examiner i UNITED STATES PATENTS 1,289,837'12/18' Love 33-62 2,049,034 7/36 Weisz 33-62 2,963,790' 12/60 Hall 3362 1 y l UFOREIGN, PATENTS 14,338 3/11 Denmark.

7,283 10/42 France.

587,542 11/33 Germany.

.40 ISAAC LISANN, Primary Examiner.