Abstract:
A rotationally symmetric timepiece wherein time information is displayed along an axis that is marked in 13 locations with axially symmetric markers. The 13 markers divide the axis into 12 sections of preferably equal length as well as mark the ends of the axis. Time information is displayed by one or more indicators which move along the axis at controlled rates. To display hour information, an indicator, which encircles the axis, is moved along the axis at a speed such that it travels the full length of the axis in a 12-hour period. At the end of this period, the indicator is preferably reset back to the first indicator. To display minute and second information, two additional indicators are used. The minute indicator is made to travel the length of the axis every hour before being reset, while the second indicator travels the length of the axis over a period of one minute before it is reset. The indicators are of different diameters so they do not interfere with each other as they travel along the axis.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to timepieces of the analog type, and more particularly to an analog timepiece which can be viewed from substantially any angle about a particular axis without loss of precision. 
     2. Brief Description of the Prior Art 
     Current timepieces, analog as well as digital, are capable of displaying time information with precisions down to the second or below. Most current displays, however, including most analog and digital displays, are effective only when viewed from a narrow range of angles about the direction normal to the face of the timepiece. At best, conventional clock displays such as dial plate or numbered displays can only be viewed at angles within 90° of the direction normal to the display face. Usually, the range of viewing angles is less than ±90°. An hourglass is an example of an analog display that can be viewed through a full 360° range about the vertical axis passing through the indicator substance passageway from upper chamber to lower chamber. In the case of an hourglass, this range of viewing angles is ordered around the vertical axis of the timepiece. However, for obvious reasons, precise display of time information, such as the time of day in terms of hours, minutes, and seconds, is very difficult to achieve with timepieces based on the hourglass principle. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an analog horological display device having geometry that can both precisely display time information and be viewed from any direction about its main axis. 
     It is also the object of the present invention to provide an analog timepiece that can both precisely display time information and be viewed from any direction about a vertical axis. 
     According to a preferred embodiment of the present invention, time information is displayed along an axis that is marked in 13 locations with axially symmetric markers. The 13 markers divide the axis into 12 sections of preferably equal length as well as mark the ends of the axis. Time information is displayed by one or more indicators which move along the axis at controlled rates. To display hour information, an indicator, which encircles the axis, is moved along the axis at a speed such that it travels the full length of the axis in a 12-hour period. At the end of this period, the indicator is preferably reset back to the first indicator. To display minute and second information, two additional indicators are used. The minute indicator is made to travel the length of the axis every hour before being reset, while the second indicator travels the length of the axis over a period of one minute before it is reset. The indicators are of different diameters so they do not interfere with each other as they travel along the axis. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view of a rotationally symmetric time display comprised of the time axis, time markers, and time display indicators, and suggesting the overall concept of the present invention; 
     FIG. 2 is a side view of one embodiment of a rotationally symmetric timepiece in accordance with the present invention and composed of a central column with 13 markers and two indicators for displaying time of day information in terms of hours and minutes; 
     FIG. 3 is a top view of the timepiece of FIG. 2, showing the means by which the two time indicators move without interfering with each other; 
     FIG. 4 is a perspective view that shows the drive mechanisms for the hour and minute time indicators of the timepiece of FIG. 2; 
     FIG. 5 is a perspective view illustrating an alternative embodiment of the present invention; and 
     FIG. 6 is a cross-section taken along the line 6--6 in FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An example of the rotationally symmetric time display geometry 10 forming the basis of the present invention is shown in FIG. 1. The elongated time axis 11 is divided into twelve sections by thirteen axially symmetric markers 12. To facilitate the reading of time, five of the markers are larger than the other eight. Two of the larger markers 12a and 12b mark the start and end of the time axis 11, while the other three are positioned to divide the time axis 11 into four equal length sections. The smaller markers 12c are positioned to further divide the time axis 11 into twelve equal length sections. Time of day information in terms of hours and minutes is displayed by the time indicators 13 and 14. Hour information is displayed by the hour indicator 13, which is made to travel the length of time axis 11 at a uniform rate over a twelve hour period. When the hour indicator 13 reaches the last marker 12b after twelve hours of travel, it is preferably reset back to the first marker 12a at the start of the time axis 11. Minute information is displayed by the minute indicator 14, which is made to travel the length of time axis 11 at a uniform rate over a one hour period. When the minute indicator 14 reaches the last marker 12b after one hour of travel, it is reset back to the first marker 12a at the start of the time axis 11. In the example shown in FIG. 1, a time of day of approximately 3:44 is displayed. 
     Although in the foregoing description the markers are depicted as spheres, other axially symmetric shapes, such as disks or bands, could be used for the markers. Even other shapes which are not perfectly symmetrical about an axis, such as triangles, squares, or octagons, could be used for the markers without significantly compromising the viewability of the time display from all directions about the main axis of the display. 
     Furthermore, although in the foregoing description the time indicators are depicted as rings, other axially symmetric shapes, such as bands, could be used for the indicators. Even other shapes which are not perfectly symmetrical about an axis, such as triangles, squares, or octagons, could be used for the time indicators without significantly compromising the viewability of the time display from all directions about the main axis of the display. 
     Moreover, although in the foregoing description the time axis is divided into twelve equal length sections, additional markers could be used to divide the time axis into a different number of sections such as 24. 
     One example of a rotationally symmetric analog timepiece 15 based on the rotationally symmetric time display geometry 10 of FIG. 1 is shown in FIG. 2. In this timepiece 15, a column 16 serves as the time axis, and is divided into twelve equal length sections by thirteen markers 17. To facilitate the reading of time, five of the markers are made thicker and extend farther from the column than the other eight. Two of the larger markers 17a and 17b mark the top and bottom of the column 16, and serve as the start and end of the time axis respectively. The other three larger markers are positioned to divide the column 16 into four equal length sections. The smaller markers 17c are positioned to further divide the column 16 into twelve equal length sections. Time of day information in terms of hours and minutes is displayed by the time rings 18 and 19. Hour information is displayed by the hour ring 18, which is made to travel the length of the column 16 at a uniform rate over a twelve hour period. When the hour ring 18 moves downwardly from the first marker 17a and reaches the last marker 17b after twelve hours of travel, it is reset back to its starting position at the first marker 17a at the top of the column 16. Minute information is displayed by the minute ring 19, which is made to travel the length of the column 16 at a uniform rate over a one hour period. When the minute ring 19 reaches the last marker 17b after one hour of travel, it is reset back to its starting position at the first marker 17a at the top of the column 16. In the example shown in FIG. 2, a time of day of approximately 8:17 is displayed. The column 16 is held in an upright position by a base 20, and the top of the column is covered by a cap 21. 
     As shown in FIG. 3, the two time rings 18 and 19 of the timepiece 15 of FIG. 2 are designed so that they can travel up and down the column 16 without interfering with each other or with the markers 17. Specifically, the hour ring 18 is designed with an inner diameter that is larger than the outer diameter of the largest markers 17. The minute ring 19 is designed with an inner diameter that is larger than the outer diameter of the hour ring 18. As will be described in more detail below, minute and hour control mechanisms 22 and 24 are disposed within the column 16. The minute ring 19 is connected to the minute control mechanism 22 by a minute control arm 23. The hour ring 18 is connected to the hour control mechanism 24 by a pair of hour control arms 25. The minute and hour control mechanisms 22 and 24 are positioned so that the hour control arms 25 can connect to the hour control mechanism 24 without interfering with the minute control mechanism 22 or the minute control arm 23 as each moves back and forth between the top and bottom of the column 16. 
     Examples of the minute and hour control mechanisms 22 and 24 of the timepiece 15 of FIG. 3 are shown in FIG. 4. The minute control mechanism 22 is composed of two minute wheels 26a and 26b which support a minute band 27. The minute ring 19 is attached to the minute band 27 by the minute control arm 23. The lower minute wheel 26b is rotated by the minute drive mechanism 28 at a controlled rate so that the minute ring 19 moves downward and traverses its full length of travel in a period of one hour. The minute drive mechanism 28 is connected to the lower minute wheel 26b by the minute clutch 29 which is controlled by the minute sensor mechanism 30 and is normally engaged. Respectively attached to the bands 27 and 33 are weights 31 and 37 which serve the dual purposes of providing (1) clutch engagement means, and (2) ring return means. When the minute control arm 23 contacts the minute sensor mechanism 30, the minute clutch 29 is disengaged. When the minute clutch 29 is disengaged, the minute wheels 26a and 26b are free to rotate allowing the minute weight 31 to drop until it contacts the minute sensor mechanism 30. As it drops, weight 31 pulls the minute ring 19 back up to its starting position. When the minute weight 31 contacts the minute sensor mechanism 30 the minute clutch 29 is re-engaged allowing the minute ring 19 to begin its downward motion, again displaying minute information. The hour control mechanism 24 is similar to the minute control mechanism 33. The hour ring 18 is attached to the hour band 33 by the hour control arms 25. The lower hour wheel 32b is rotated by the hour drive mechanism 34 at a controlled rate so that the hour ring 18 moves downward and traverses its full length of travel in a period of twelve hours. The hour drive mechanism 34 is connected to the lower hour wheel 32b by the hour clutch 35 which is controlled by the hour sensor mechanism 36 and is normally engaged. When either one of the hour control arms 25 contacts the hour sensor mechanism 36, the hour clutch 35 is disengaged rendering the hour wheels 32a and 32b free to rotate and allowing the hour weight 37 to drop until it contacts the hour sensor mechanism 36. As weight 37 drops, it pulls the hour ring 18 back up to its starting position. When the hour weight 37 contacts the hour sensor mechanism 36, the hour clutch 35 is re-engaged allowing the hour ring 18 to begin its travel down the column and again display hour information. 
     Although in the foregoing illustration and description only hour and minute information are disclosed, it is also possible to add a third ring and control mechanism to display second information. 
     Whereas in the foregoing description the clutches are controlled by the sensor mechanisms, it is also possible to control the clutches with an external timing and control mechanism. 
     Similarly, whereas in the foregoing description the time rings are controlled by drive mechanisms which are each composed of two wheels and a band, it is also possible to control the time rings with alternate control mechanisms. 
     Moreover, although in the foregoing description neither the markers nor the rings are illuminated, it is also possible that either the markers or the rings, or both, could be made luminous to facilitate the reading of time information without external illumination of the timepiece. In addition, or in the alternative, the column 16 could be illuminated. 
     As described above, this invention provides a rotationally symmetric time display geometry which allows for a precise display of time information that is viewable from any direction about its main axis. This invention further provides an analog timepiece that can both precisely display time information and that can be viewed from any direction about a vertical axis. This type of timepiece is suitable for use as a stand alone analog time display or for use in incorporating the rotationally symmetric time display geometry into other objects such as the base of a lamp. Both the markers and the indicators can be made luminous to facilitate the reading of time information when the ambient lighting is low. 
     Even though the present invention has been described above as having equal spacing between time markers, with rings traveling at uniform rates down the column, it will be appreciated that there might be applications in which one would, for variation of effect, or other reasons, want to have different spacings between the hour markers and provide variable rate drive means that would appropriately change the rate of movement of the rings as they are moved along the column so that they move at rates proportional to the spacings between markers as they transit such space. Such rate changes could for example be effected by appropriately programming electronic stepper motors used in the drive mechanisms. 
     Another variation might be to cause the hour indicator to rise from the bottom to the top of the column during the AM hours and to move from the top to the bottom during the PM hours, perhaps using a flag of some type, or a change in lighting or color, etc., to indicate AM/PM periods. 
     In an alternative embodiment such as that depicted in FIG. 5 of the drawing, and in FIG. 6 (a cross-section taken along the line 6--6 in FIG. 5), the time axis might be made curved or endless; e.g., the &#34;column 16&#34; might be folded end-to-end and connected to form a circular loop 38 or other ellipse. In such case, suitable toothed belt drive motors 40, 42, 44 and belt guides 46, 48, 50 would be provided for facilitating movement of second, minute and hour ring-carrying belts 52, 54, 56 around the loop. And as in the previously described embodiment, suitable markers 58 may be placed at predetermined intervals around the loop marking off 12 (or 24) hours of time as well as intervening minutes and/or seconds if desired. The loop might be hung from hangers 60 and 62 which are cleared by the gaps 64, 66, 68 in the rings 65, 67, 69 as they pass around the loop. Although this embodiment is not strictly viewable from 360°, it is readable from nearly all angles outside the plane of the loop. 
     While the invention has been described in terms of specific examples and specific embodiments, it is to be understood that this invention is not limited to these specific examples and embodiments and that many changes and modified embodiments will be apparent to those skilled in the art without departing from the true spirit and scope of the invention.