US3230435A

US3230435A - Lock-out device

Info

Publication number: US3230435A
Application number: US341927A
Authority: US
Inventors: William F Andrews
Original assignee: Ampex Corp
Current assignee: Ampex Corp
Priority date: 1964-02-03
Filing date: 1964-02-03
Publication date: 1966-01-18
Anticipated expiration: 1983-01-18

Description

United States Patent 3,230,435 LOCK-OUT DEVICE William F. Andrews, San Mateo, Calif., assignor to Ampex Corporation, Redwood City, Calif., a corporation of California Filed Feb. 3, 1964, Ser. No. 341,927 5 Claims. (Cl. 318-284) This invention relates to a lock-out device and more particularly to a recorder lock-out device which assures that the recording medium driving means may not be re-energized until the driving means has completely stopped [following its de-energizlation.

It has been observed in many recorders that the decnergization and subsequent deceleration of the capstan motor followed by the re-energization and acceleration of the capstan motor results in the tossing of the tape off the reel or in a departure of the tape from its normal path. This stop and start energizing of the capstan motor may also cause undue wear and stretching of the tape.

In order to remedy the above problems a lock-out device has been invented which prevents the energiza-tion oi the capstan motor or drive means following its deenergizat-ion until its movement has terminated. The lock-out device which accomplishes these functions comprises a sensing means for sensing the deceleration or deenergization of the driving means and a lockout or prevention means operatively coupled to the sensing means for preventing the energization of the driving means until the driving means has stopped its movement.

It is the general object of this invention to provide an improved lock-out device;

Another object of this invention is to provide a lockout device for a recorder;

Another object of this invention is to provide a lockout device which prevents the re-energization of the driving means of a recorder until it has terminated its movement;

Another object of this invention is to provide a lockout device which utilizes a signal from the driving means to substantially control the period of eifectiveness of the lock-out device;

Another object of this invention is to provide a lockout device for a recorder so that the wear and stretching of the tape of the recording medium. is minimized;

Another object of this invention is to provide a lockout device for a recorder which prevents the starting and stopping of the driving means [from tossing the recording medium from its normal path.

These and other objects will be apparent when the detailed description is taken in conjunction with the sole figure which is a simplified electrical schematic diagram of anembodiment of the invention.

Referring to the figure the drive or motor means is connected to a capstan 12 to drive a movable recording medium 14. The motor means 10 is normally energized by an A.C. power source such as the 117 volt A.C. source 16. The power source 16 is connected to the motor via a contact 18 and a switch arm 28. The switch arm 20 is moved between the contact 18 and a contact 22 by a relay coil or more particularly a reproduce relay coil 24 which is magnetically or mechanically coupled to the switch arm 20. It should be understood that the invention though described with regards to the reproduce relay coil 24 may be applied to the record relay coil or both the record and reproduce relay coils or to any other coils or devices that control the energization of the motor means 10. When the reproduce relay coil 24 is de-energized the switch arm 20 abuts the contact 22 as shown by the broken line. The energization of the reproduce relay coil 24 results in the switch arm 20 abutting the contact 18 and also results in a switch arm 26 abutting a contact 28. The switch arm 26 and contact 28 form part of a hold circuit that maintains the energization of the reproduce relay coil 24. Before the relay coil 24 is energized, the switch arm 26 is connected to a contact 30 which is an open contact.

Energization of the reproduce relay 24 may be accomplished by momentarily depressing the push-button switch 34 to bridge the

contacts

36 and 38. The completion of a circuit from the contact 36 to the contact 38 results in a power supply such as the 115 volt D.C. supply 40 being connected to the reproduce relay 24. The circuit which forms the connection from the supply 40 to the reproduce relay 24 comprises a normally closed pushbutton switch 44 which is connected to power source 40 and to the contact 38 by a conductor 46, a switch arm 48, a contact and a conductor 52.

From the above description it .can be seen that when the push-button switch 34 is depressed, a circuit is completed from the voltage source 40 to the reproduce relay 24 via the push-button switch 44 and the switch arm 48. The completion of this circuit results in the energization of the reproduce relay 24 which in turn causes the switch arm 26 to be connected to the contact 28. The connection of the switch arm 26 to the contact 28 results in a holding circuit being completed from the voltage source 40 to the reproduce relay 24 which is not affected by the subsequent release of the push-button 34. This holding circuit mzu'ntains the switch arm. 20 in abutment with the contact 18 so that the motor 10 is energized by the A.C. voltage source 16.

In many recorders it is possible to actuate a push-button switch to stop the movement of the motor 10 and the recording medium 14 and then to immediately depress a push-button to energize the motor 10 to move the recording medium 14 before the motor and medium have completely stopped. This sequence Oif events may result in the tossing of the tape from its normal path and in undue stretching and wearing of the recording medium. To prevent these disadvantages a lock-out device has been invented.

The lock-out device includes the contact 22 which is associated with the switch arm 20. The contact 22 is connected to a sensing means for sensing the deceleration or de-energization Of the motor 10, and is connected to the motor 10 when the switch arm 20 is moved to the right by the de-energization of the reproduce relay coil 24. The moving of the switch arm 20 from the contact 18 disconnects the motor from the A.C. voltage source 16 and applies the back electro-motive force (E.M.F.) or voltage generated by the motor 10 to the sensing means 60 via the switch arm 20 and contact 22. The sensing means 60 comprises a rectifier or a rectifier circuit means 62 and a sensing relay 64. The rectifier means 62 converts the alternating back voltage to a D.C. voltage adapted to energize the sensing relay 64. The rectifier circuit means may be constructed from the following circuit elements:

Elements: Values of the elements Resistor 65 15 ohm, 1 watt. Resistor 66 15 ohm, 1 watt. Diode 68 D1-56. Diode 70 D1-56 Capacitor 72 200 micro-farads, 15 volts. Capacitor 74 200 micro-farads, 15 volts. Zener diode 76 1Nl594A. Sensing relay 64 Reed type relay, MA.

The Zener diode 76 functions to limit the voltage supplied to the sensing relay coil 64.

The energization of the sensing relay coil 64 by the rectifier means 62 closes a switch arm 78 thereby connecting switch arm 78 to the D.C. voltage supply 40 via a current limiting resistor 80 and a contact 82. The switch arm 78 and the associated structure may be considered part of a means for preventing the re-energization of the motor while it is decelerating or stopping due to its de-energization. The means for preventing re-energization of the motor 10 also includes a lock-out relay coil 84 which is energized when the switch arm 78 abuts the contact 82. The lock-out relay coil 84 is mechanically or magnetically coupled to control a plurality of switch arms and contacts. More particularly the energization of the relay coil 84- moves switch arm 48 from contact 58 to an open contact 86 (as shown by the broken lines) and moves a switch arm 88 from an open contact 90 to a contact 92. The contact 92 is connected to the switch arm 78. The switch arm 88 is connected to ground via a capacitor 94.

The moving of the switch arm 88 to abut the contact 92 results in the capacitor 94 being energized by the D.C. voltage source 40 via the contact 82 and the switch arm 78, assuming that switch arm 78 has been closed by the energization of the sensing relay coil 64. The movement of the switch arm 48 from the contact 50 to the open contacts 86 by the energization of the delay coil 84 open circuits the connection from the DC. voltage supply 40 to the contact 38 of the push-button 34. As a result of this open circuit the depression of push-button switch 34 will be ineffective to energize the reproduce relay coil 24. This condition will continue so long as the lock-out relay coil 84 is energized to maintain the switch arm 48 in abutment with the open contact 86.

It has been found that in some cases the voltage generated by the deceleration of the motor 10, such as that generated at low motor speeds, is not of sufiicient magnitude to maintain the energization of the sensing relay coil 64 and consequently the energization of the relay coil 84. It can be seen that the de-energization of the sensing relay coil 64 and the opening of the switch arm 78 would result in the lock-out relay coil 84 no longer being energized by the DC. voltage source 40. This deenergization of coil 84 and accompanying movement of switch arm 48 to abut contact 50 would allow the motor 10 to again be energized by the actuation of the switch 34. To avoid this the capacitor 94 is provided and it is charged while the switch arm 78 abuts contact 82. When the switch arm 78 is opened, the capacitor 94 acts as a DC. voltage source which maintains the energization of the lock-out relay coil 84 for a period of sufitcient length to assure that the motor 10 has completely terminated its movement before the push-button 34 can again effectuate the energization of motor 10 via switch arm 48. When the capacitor 94 has discharged to a voltage equal to the de-energization level of the lock-out relay coil 84 the switch arm 48 will return to its normally de-energized position abutting the contact 50 and the switch arm 88 will return to abut the open contact 90. With the switch arm 48 in abutment with the contact 50 the motor 10 will again be susceptible to energization by actuation of the push-button switch 34.

In summary, normally the motor 10 is energized by the actuation of the push-button switch 34 which completes the circuit from the DC. voltage source 40 to the reproduce relay coil 24. The energization of the reproduce relay coil 24 causes the switch arm 26 to abut the contact 28 which completes a holding circuit to maintain the energization of the reproduce relay coil 24. Simultaneously the switch arm is moved to abut the contact 18 which causes the AC. voltage source 16 to be connected to energize the motor 10.

The subsequent actuation of the stop push-button switch 44 breaks the hold circuit to the reproduce relay coil 24 causing the switch arm 26 to abut the open contact 30 and causing the switch arm 20 to abut the contact 22. The switch arm 20 now connects the motor 18 to the sensing means 60 and de-energizes the motor. The tie-energization of the motor 10 results in its deceleration and generation of a back that is supplied to the sensing means 68 via the contact 22 which in turn enables the means for preventing the re-energization of the motor 10. This means for preventing the re-energization of the motor includes the lookout relay coil 84 which is energized via the contact 82 and the switch arm 78. The energization of the relay coil 84 open circuits the connection between the power source 48 and the contact 38 by moving the switch arm 48 to abut the open contact 86. The switch arm 88 is also moved to abut the contact 92 which results in the charging of capacitor 94. The capacitor 94 acts as a means to assure that the re-energization of the motor 18 cannot take place until the motor has completely terminated its movement. This is accomplished by capacitor 94 acting as a voltage source for a given period of time thereby maintaining the lock-out relay coil 84 in an energized state so that the switch arm 48 is retained in abutment with the open contact 86 notwithstanding the de-energization of relay coil 64. Eventually the capacitor 94 discharges and the lock-out relay coil 84 is de-energized and the push-button 34 may again be depressed to re-energize the motor 10. The motor 10 can then rotate the capstan 12 to drive the movable recording medium 14.

From the description it can be seen that a lock-out device has been invented which improves recorder operation. The invented lock-out device assures that the drive means for a recording medium will have its movement completely terminated before it may be re-energized following a de-energization. This type of lock-out device prevents any unnecessary stretching or wearing of the tape and insures that the tape will not be injured by some premature inadvertent depression of the reproduce push-button switch 34. It is to be understood that the principle of the invention is applicable to any function of a re corder or similar device that requires movement of the motor or drive means. The record function, fast forward, reverse function or rewind, are typical functions for which the invention is well suited.

While the above detailed description has shown, described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device and method illustrated may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a recorder having a movable recording medium, the combination comprising:

motor means for moving said recording medium;

said motor means coupled to the recording medium to drive said recording medium;

means for energizing said motor means operatively coupled to said motor means;

means for de-energizing said motor means operatively coupled between said motor means and said means for energizing;

first circuit means op-eratively coupled via said means for tie-energizing to said motor means for sensing when said motor means has been de-energized and for transmitting a voltage as a result of sensing the de-energization; and

second circuit means including voltage prolonging circuit means for preventing the energization of the drive means following its de-energization until said motor means has completely terminated its movement;

said second circuit means operatively coupled between said first circuit means and said means for de-energizing to be enabled by the voltage transmitted from said first circuit means and prolonged by said second circuit means, said second circuit means precluding initiation of said means for energizing until said motor means has completely terminated its movement.

2. The structure defined in claim 1, wherein:

said sensing means includes a rectifier circuit means connected in circuit with said motor means for rectifying the voltage generated by said motor means when said motor means is de-energized and decelerates; and

sensing relay means for enabling said second circuit means to prevent said energization of said motor; said sensing relay means connected in circuit with said rectifier means.

3. The structure defined in claim 2 wherein said second circuit means includes a means for preventing energization of said motor means for a given period of time regardless of the continued effectiveness of said sensing relay.

4. The structure defined in claim 3 wherein said means for preventing energization of said motor means for a fixed period of time comprises a capacitor adapted to be connected to said second circuit means.

5. The combination comprising:

recording medium supported for movement;

motor means for moving said recording medium and for generating a back when de-energized; first power source for energizing said motor means; rectifier means for rectifying any motor means back to a DC. voltage;

first contact;

second contact;

first switch arm connected to said motor means and movable to abut said first contact or said second contact;

said first contact connected to said rectifier means;

said second contact connected to said first power source;

first relay means for moving said first switch arm from said second contact to abut said first contact when energized, whereby said motor is connected to said rectifier means;

second power source;

third contact;

fourth contact;

said third contact open connected;

said fourth contact connected to said first relay means;

second switch arm movable to abut said third or fourth contacts and connected to said second power source;

capacitor;

third switch arm connected to said capacitor;

fifth contact;

sixth contact;

said fifth contact open connected;

second relay means for moving said second switch arm to abut said third contact when energized and for moving said third switch arm to abut said sixth contact when energized;

said second relay means connected to said sixth contact;

seventh contact connected to said second power source;

fourth switch arm connected to said sixth contact and movable to abut said seventh contact; and

sensing relay means for moving said fourth switch arm to abut said seventh contact when energized by the rectified back E.M.F.;

said sensing relay means connected to said rectifier means, whereby the motor means may not be energized by said first power source until said sensing relay means is tie-energized and said capacitor is discharged.

References Cited by the Examiner UNITED STATES PATENTS 3,044,725 7/1962 Garns et a1 242-55.12

FOREIGN PATENTS 155,881 3/1954 Australia.

MILTON O. HIRSHFIELD, Primary Examiner. J. BERENZWEIG, Assistant Examiner.

Claims

1. IN A RECORDER HAVING A MOVABLE RECORDING MEDIUM, THE COMBINATION COMPRISING: MOTOR MEANS FOR MOVING SAID RECORDING MEDIUM; SAID MOTOR MEANS COUPLED TO THE RECORDING MEDIUM TO DRIVE SAID RECORDING MEDIUM; MEANS FOR ENERGIZING SAID MOTOR MEANS OPERATIVELY COUPLED TO SAID MOTOR MEANS; MEANS FOR DE-ENERGIZING SAID MOTOR MEANS OPERATIVELY COUPLED BETWEEN SAID MOTOR MEANS AND SAID MEANS FOR ENERGIZING; FIRST CIRCUIT MEANS OPERATIVELY COUPLED VIA SAID MEANS FOR DE-ENERGIZING TO SAID MOTOR MEANS FOR SENSING WHEN SAID MOTOR MEANS HAS BEEN DE-ENERGIZED AND FOR TRANSMITTING A VOLTAGE AS A RESULT OF SENSING THE DE-ENERGIZATION; AND