Time measurement device and method

• US 6,724,692 B1
• Filed: 04/19/2000
• Issued: 04/20/2004
• Est. Priority Date: 04/21/1998
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Maruyama, Akihiko, Akahane, Hidehiro, Okuhara, Kenichi, Koike, Nobuhiro
• Primary Examiner(s): Martin, David
• Assistant Examiner(s): GOODWIN, JEANNE M
• Application Number:
  US09/446,449
• Time in Patent Office: 1,462 Days
• Field of Search: 368/66, 368/204, 368/64, 368/157, 368/160, 368/89, 368/107
• US Class Current: 368/204
• CPC Class Codes: G04F 8/00 Apparatus for measuring unknown time intervals by electromechanical means
• CPC Class Codes: G04F 8/08 Means used apart from the time-piece for starting or stopping same

Abstract

A mechanism having at least a function of measuring an arbitrary elapsed time is provided, which disables the function from being reset after the function is started, and enables the function to be reset after the function is stopped. The function is continuously held in an electrical ON state after being started, except when being normally stopped. This provides a time measurement device and method in which an electrical operating state and a mechanical operating state can coincide.

Claims

1. A time measurement device, comprising:

a power source;

a function of measuring elapsed time;

an input unit for inputting start and stop electrical signals for respectively starting and stopping the measurement of the function;

a reset circuit for enabling output of an electrical reset signal, after measurement of the function is stopped by the stop electrical signal;

a mechanical return-to-reset mechanism for resetting the function;

a mechanical safety mechanism for disabling the function from being mechanically reset between the time that measurement of the function is started by the start electrical signal and the time that measurement of the function is stopped by the stop electrical signal, and for enabling the function to be mechanically reset after measurement of the function is stopped; and

a control section for maintaining the function in an electrical ON-state, initiated by receipt of the start electrical signal, during the time that measurement of the function is performed, and for maintaining the function in the electrical OFF-state, initiated by receipt of the stop electrical signal, during the time that measurement of the function is not performed;

wherein, if the voltage of the power source falls below a minimum voltage level required for performing the function after measurement of the function is started and thereafter rises to at least the minimum voltage level, the control section continuously maintains the electrical ON-state during the time that the power source voltage is below the minimum voltage level, and the mechanical safety mechanism continuously disables the function from being mechanically reset during the time that the power source voltage is below the minimum voltage level.

2. A time measurement device according to claim 1, further comprising a hand for indicating the elapsed time.

3. A time measurement device according to claim 1, wherein the input unit comprises a switch.

4. A time measurement device according to claim 2, further comprising a motor for driving the hand.

5. A time measurement device according to claim 1, wherein the control section comprises:

a pattern on a circuit substrate; and

a lever;

wherein the electrical ON-state initiated by receipt of the start electrical signal is continuously maintained by keeping the lever in mechanical contact with the pattern.

6. A time measurement device according to claim 1, wherein the control section comprises:

a first circuit for receiving a first pulse signal and a second pulse signal, the first and second pulse signals having different frequencies, and for outputting a third pulse signal that is adjusted to a first level when a level of the second pulse signal falls, and is adjusted to a second level when a level of the first pulse signal falls;

a second circuit for receiving an actuating signal from the input unit and the third pulse signal from the first circuit, and for outputting a fourth pulse signal that is adjusted to the second level when a level of the third pulse signal rises and the actuating signal is at the second level, and is adjusted to the first level when the level of the third pulse signal rises and the actuating signal is at the first level;

a third circuit for receiving the fourth pulse signal and the second pulse signal, and for outputting a fifth pulse signal that is adjusted to the first level when the level of the second pulse signal rises, adjusted to the second level when the level of the second pulse signal falls and the fourth pulse signal level is at the first level, and adjusted to the first level when the level of the second pulse signal falls and the fourth pulse signal is at the second level, wherein the fifth pulse signal is for continuously maintaining the electrical ON-state initiated by receipt of the start electrical signal; and

a lever for holding an output level of the fifth pulse signal by being in mechanical contact with a pattern on a circuit substrate.

7. A time measurement device according to claim 1, wherein the power source is a chargeable secondary power source.

8. A time measurement device according to claim 1, wherein the chargeable secondary power source is a chargeable button-type battery.

9. A time measurement device, comprising:

a hand for indicating at least an arbitrary measured elapsed time;

a first actuating section for starting and stopping the hand;

a second actuating section for returning the hand to a reset position;

a safety mechanism for disabling the second actuating section when the hand is driven by the first actuating section , and for activating the second actuating section when the hand is stopped by the first actuating section; and

a control section for continuously maintaining a driving signal for driving the hand from the time the hand is driven by the first actuating section until the hand is normally stopped;

wherein the control section has a pattern on a circuit board, and a lever for making mechanical contact with the pattern, the driving signal for the hand being continuously maintained by keeping the lever in contact with the pattern; and

wherein the control section includes a pull-up resistor or a pull-down resistor for determining a signal output to the pattern, a sampling circuit for intermittently operating the pull-up resistor or the pull-down resistor, and a holding circuit for recognizing the signal output to the pattern during a sampling period in which the pull-down resistor or the pull-up resistor is intermittently operated by the sampling circuit and for holding and outputting the recognized signal except when the signal is recognized.