Digital-to-digital correction unit for analog clock display

Abstract

A clock device for timekeeping with an analog display and a time correction unit. The time correction unit uses encoder disks and rotary encoders to convert the angular position of the minute hand and the hour hand to a slave time code. The slave time code is compared to a master time code. A feedback circuit drives the minute hand and hour hand drive-motor(s) until the slave time code equals the master time code. The master time code can be generated from a digital clockworks, or it can be transmitted to the present invention from another clock. The invention can be extended to include a second hand and a time correction unit for a second hand.

Claims

1. A clock device with an analog display and a time correction unit comprising an analog clock dial with an hour hand and a minute hand in proximity to, and parallel with, the clock dial; an hour-hand shaft connected to and supporting the hour hand; a minute-hand shaft connected to and supporting the minute hand; wherein the relative position of the hour hand and hour-hand shaft with respect to the analog clock dial is the angular position of the hour hand and hour-hand shaft; and wherein the relative position of the minute hand and minute-hand shaft with respect to the analog clock dial is the angular position of the minute hand and minute-hand shaft; an hour-hand digital encoder disk with peripheral cogs, encoded with information identifying the angular position of at least one of the hour-hand and the hour-hand shaft; a minute-hand digital encoder disk with peripheral cogs, encoded with information identifying the angular position of at least one of the minute-hand and minute-hand shaft; a first non-slip coupling, permanently attaching the center of the hour-hand digital encoder disk to the hour-hand shaft in a non-slip fashion; a second non-slip coupling, permanently attaching the center of the minute-hand digital encoder disk to the minute-hand shaft in a non-slip fashion; an hour-hand drive motor, attached to the hour-hand digital encoder disk with a cogwheel; a minute-hand drive motor, attached to the minute-hand digital encoder disk with a cogwheel; an hour-hand rotary encoder, comprised of at least one sensor capable of reading the angular position information from the hour-hand encoder disk; a minute-hand rotary encoder, comprised of at least one sensor capable of reading the angular position information from the minute-hand encoder disk; a circuit that converts the angular position information from the minute-hand rotary encoder and the angular position information from the hour-hand rotary encoder into a slave time code; a master time code from a digital clock source; a feedback circuit that controls the speed of the minute-hand drive motor and the hour-hand drive motor, so that the slave time code continuously equals the master time code; wherein the angular position information encoded on the minute-hand encoder disk is arranged in at least six concentric circles, with at least six discrete radii, corresponding to a BCD integer of at least six bits; and wherein the angular position information encoded on the hour-hand encoder disk is arranged in at least six concentric circles, with at least six discrete radii, corresponding to a BCD integer of at least six bits.

2. The clock device with an analog display and time correction unit of claim 1, wherein the hour-hand encoder disk stores angular position information on a readable magnetic substrate.

3. The clock device with an analog display and time correction unit of claim 2, wherein the at least one hour-hand rotary encoder sensor is a Hall Effect sensor.

4. The clock device with an analog display and time correction unit of claim 2, wherein the at least one hour-hand rotary encoder sensor is a microelectromechanical sensor (MEMS).

5. The clock device with an analog display and time correction unit of claim 2, wherein the minute-hand encoder disk stores angular position information on a readable magnetic substrate.

6. The clock device with an analog display and time correction unit of claim 5, wherein the at least one minute-hand rotary encoder sensor is a Hall Effect sensor.

7. The clock device with an analog display and time correction unit of claim 5, wherein the at least one minute-hand rotary encoder sensor is a microelectromechanical sensor (MEMS).

8. The clock device with an analog display and time correction unit of claim 2, wherein the minute-hand encoder disk stores angular position information on an optically readable substrate.

9. The clock device with an analog display and time correction unit of claim 8, wherein the at least one minute-hand rotary encoder sensor uses at least one LED and at least one photodiode.

10. The clock device with an analog display and time correction unit of claim 8, wherein the at least one minute-hand rotary encoder sensor uses at least one laser and at least one photodiode.

11. The clock device with an analog display and time correction unit of claim 1, wherein the hour-hand encoder disk stores angular position information on an optically readable substrate.

12. The clock device with an analog display and time correction unit of claim 11, wherein the at least one hour-hand rotary encoder sensor uses at least one LED and at least one photodiode.

13. The clock device with an analog display and time correction unit of claim 11, wherein the at least one hour-hand rotary encoder sensor uses at least one laser and at least one photodiode.

14. The clock device with an analog display and time correction unit of claim 11, wherein the minute-hand encoder disk stores angular position information on a readable magnetic substrate.

15. The clock device with an analog display and time correction unit of claim 14, wherein the at least one minute-hand rotary encoder sensor is a Hall Effect sensor.

16. The clock device with an analog display and time correction unit of claim 14, wherein the at least one minute-hand rotary encoder sensor is a microelectromechanical sensor (MEMS).

17. The clock device with an analog display and time correction unit of claim 11, wherein the minute-hand encoder disk stores angular position information on an optically readable substrate.

18. The clock device with an analog display and time correction unit of claim 17, wherein the at least one minute-hand rotary encoder sensor uses at least one LED and at least one photodiode.

19. The clock device with an analog display and time correction unit of claim 17, wherein the at least one minute-hand rotary encoder sensor uses at least one laser and at least one photodiode.

20. The clock device with an analog display and time correction unit of claim 1, further comprising a second-hand, a second-hand shaft, a second-hand coupling, a second-hand encoder disk, a second-hand drive motor, and a second-hand rotary encoder; and wherein the angular position information encoded on the second-hand encoder disk is arranged in at least six concentric circles, with at least six discrete radii, corresponding to a BCD integer of at least six bits.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is illustrated with 9 drawings on 8 sheets.

(2) FIG. 1 is a side view of the present invention.

(3) FIG. 2A is a top view of an optical encoder disk.

(4) FIG. 2B is a side view of an optical encoder disk.

(5) FIG. 2C is an isometric view of an optical encoder disk.

(6) FIGS. 3A and 3B show block diagrams.

(7) FIG. 4 is a top view of a magnetic encoder disk and an optical encoder disk.

(8) FIG. 5 is a side view of the present invention, with second-hand.

(9) FIG. 6 is a perspective view of the present invention.

(10) FIG. 7 is a side view of an alternative embodiment of the present invention.

(11) FIG. 8 is a side view of an alternative embodiment of the present invention.

(12) FIG. 9 is a side view of an alternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(13) The following descriptions are not meant to limit the invention, but rather to add to the summary of invention, and illustrate the present invention, a Digital-to-Digital Correction Unit for an Analog Clock Display. The Digital-to-Digital Correction Unit for an Analog Clock Display is a clock device with an analog clock dial and a digital-to-digital correction unit. The present invention is illustrated with a variety of drawings showing various possible embodiments.

(14) FIG. 1 shows a side view of the present invention. A minute-hand drive-shaft 2 is attached to a minute hand 211. The minute-hand drive-shaft 2 is also attached to a minute-hand encoder disk 13 with a non-slip coupling 5. Likewise, an hour-hand drive-shaft 3 is attached to an hour hand 210. The hour-hand drive-shaft 3 is also attached to an hour-hand encoder disk 12 with a non-slip coupling 4. The edge of the minute-hand encoder disk 13 has a plurality of cogs. The cogs on the edge of the minute-hand encoder disk 13 engage with cogwheel attached to minute-hand shaft drive-motor 9. The edge of the hour-hand encoder disk 12 has a plurality of cogs. The cogs on the edge of the hour-hand encoder disk 12 engage with a cogwheel attached to the hour-hand shaft drive-motor 8. The surface of the minute-hand encoder disk 13 is in proximity with a minute-hand sensor pick-up assembly 7 called a rotary encoder 7. The surface of the hour-hand encoder disk 12 is in proximity with an hour-hand sensor pick-up assembly 6 called a rotary encoder 6. The present invention has a base 11. The present invention also has an analog clock display 10.

(15) FIGS. 2A, 2B, and 2C show various views of an optical encoder disk 12. The surface of the optical encoder disk 12 has a plurality of reflective zones 20, 24, radially arranged about the disk 12. The reflective zones 20, 24 are positioned about six discrete radii. Some of the reflective zones 20 are circular. Some of the reflective zones 24 are elongated around the radius. The periphery 23 of the disk 12 has a plurality of cogs (teeth) 21. The center 22 of the disk 12 engages with a non-slip coupling 4 which durably attaches the disk 12 to the shaft 3.

(16) FIG. 4 shows a magnetic encoder disk 112 and an optical encoder disk 12, side-by-side. The magnetic encoder disk has a plurality of south poles and north poles arranged radially. A radial line 59 passes through a sequence of radial bits 59 extending from the center to the outer periphery of the magnetic encoder disk 112 runs through a plurality of poles, creating BCD integers 0, 1. The radial bits 59 create a BCD integer 0, 1 when read by a suitable pick-up device. For example, the radial line 0 passes through the bits 111111, which can be interpreted as a BCD integer corresponding to hours, minutes, or seconds. Likewise, the optical encoder stores BCD integers corresponding to a sequence of radial lines 900, 901, 902, 903, 904. For example, radial line 900 passes through bits 111011, which can be interpreted as a BCD integer corresponding to hours, minutes, or seconds. The encoder disks 112, 12 uses six radial bits 600, 601, 602, 603, 604, 605, 800, 801, 802, 803, 804, 805.

(17) FIGS. 3A and 3B show block diagrams of the time correction circuitry 199 logic used in the present invention. In particular, FIGS. 3A and 3B are for an embodiment using a magnetic encoder disk. Except for the rotary hall encoder 102, the rest of the time correction circuitry 199 is the same for all embodiments. The rotary hall encoder 102 is used with a magnetic encoder disk 112, to read the radial bits 59. In FIG. 3A, by running the radial bits 59 through a digital to analog converter 101, the invention creates a BCD integer. The BCD integer can be logically converted into a time code (hours:minutes). The BCD integer from the rotary hall encoder 102, acting as a time code slave, is fed into a circuit comprised of a comparator 103 and a logic circuit that drives the motor driven hands 106. The BCD integer from the rotary hall encoder 102 is fed into the comparator 103. A time code master, from a digital clock 105 and a digital to analog converter 104 is also fed into a comparator. The results from the comparator 103 is fed into a logic circuit that drives the motor driven hands 106. When the slave time code 101 and the master time code 104 are equal, the motors are not driven. When the slave time code 101 does not equal the master time code 104, the motors rotate the hands until the slave time code 101 equals the master time code 104. The comparator 103 and logic circuit that drives the motor driven hands 106 constitute a feedback circuit 198.

(18) The master time code 104 comes from a digital clock 105, which can either be internal to the present invention, or can be transmitted to the present invention from an external digital clock 105. This allows the present invention to (1) recover from a power outage; (2) adjust to daylight savings time; and (3) be synchronized with another clock. FIG. 5 shows an embodiment of the present invention for a clock with a second hand. The present invention can incorporate a second-hand 212 by adding to the mechanism a second-hand 212, a second-hand shaft 102, a second-hand coupling 105, a second-hand encoder disk 14, a second-hand drive motor 109, and a second-hand rotary encoder 107. The system logic of the time correction circuitry 199, such as the BCD integer time code (hour:minutes:seconds) would need to be adjusted to correctly incorporate a second hand 212.

(19) FIG. 6 shows a perspective view of the present invention, using a hour hand 210 magnetic encoder disk 112 and a minute hand 211 magnetic encoder disk 113. The analog clock face 10 is visible in this view, as are the hour hand 210 and minute hand 211. The hour-hand sensor pick-up assembly 6, called an hour-hand rotary encoder 6, uses a plurality of Hall Effect Sensors 201 referred to in the logic diagram (FIG. 3) as the rotary hall encoder 102. In practice, the Hall Effect Sensors 201 would likely be flush-mounted into the hour-hand rotary encoder 6, leaving the cross-section of the hour-hand rotary encoder 6 to appear like that shown in FIG. 1. The minute-hand sensor pick-up assembly 7, called a minute-hand rotary encoder 7, uses a plurality of Hall Effect Sensors 201 referred to in the logic diagram (FIG. 3) as the rotary hall encoder 102. In practice, the Hall Effect Sensors 201 would likely be flush-mounted into the minute-hand rotary encoder 7, leaving the cross-section of the minute-hand rotary encoder 7 to appear like that shown in FIG. 1. FIG. 8 shows a lateral view of the present invention using MEMS sensors 750 with MEMS-compatible encoder disks 712, 713.

(20) FIG. 7 shows a side view of the present invention, using a hour-hand 210 optical encoder disk 12 and a minute hand 211 optical encoder disk 13. The hour-hand sensor pick-up assembly 6, called an hour-hand rotary encoder 6, uses a plurality of lasers 420 and a like number of photodiodes 426. In practice, the lasers 420 and photodiodes 426 would likely be flush-mounted into the hour-hand rotary encoder 6, leaving the cross-section of the hour-hand rotary encoder 6 to appear like that shown in FIG. 1. The minute-hand sensor pick-up assembly 7, called a minute-hand rotary encoder 7, uses a plurality of lasers 420 and a like number of photodiodes 426. In practice, the lasers 420 and photodiodes 426 would likely be flush-mounted into the minute-hand rotary encoder 7, leaving the cross-section of the minute-hand rotary encoder 7 to appear like that shown in FIG. 1. FIG. 9 shows a variation of the optical encoder disk 512, 513 in which the optical encoder disk 512, 513 allow light to pass through. In this embodiment, the light source is routinely an LED 729, and the pick-up is a photodiode 730.