# US 4,394,607 A · Control systems for gates and the like including a motor overload monitoring circuit

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- Number: US 4,394,607 A
- Document ID: US4394607A
- Status: Granted
- Kind: A
- Application number: 06/261,846
- Filed: 1981-05-08
- Granted: 1983-07-19
- Earliest claimed: 1981-05-08
- Assignees: Stanley Automatic Openers
- Inventors: Rodger P. Lemirande
- Web page: https://patentgrep.com/patent/US4394607A

## CPC

- H02H 7/0851: {for motors actuating a movable member between two end positions, e.g. detecting an end position or obstruction by overload signal}
- E05F 15/611: for swinging wings
- E05F 15/00: Power-operated mechanisms for wings (motor-operated accessories in locks for completing closing or initiating opening of a wing E05B17/00)
- E05F 15/41: Detection by monitoring transmitted force or torque (E05F15/48 takes precedence); Safety couplings with activation dependent upon torque or force, e.g. slip couplings
- E05Y 2400/822: Light emitters, e.g. light emitting diodes [LED]
- E05Y 2900/40: for gates
- H02H 3/006: {Calibration or setting of parameters}
- H02H 3/05: with means for increasing reliability, e.g. redundancy arrangements {(for logic circuits H03K19/003)}
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)
- E05F: DEVICES FOR MOVING WINGS INTO OPEN OR CLOSED POSITION; CHECKS FOR WINGS; WING FITTINGS NOT OTHERWISE PROVIDED FOR, CONCERNED WITH THE FUNCTIONING OF THE WING
- E05Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES E05D AND E05F, RELATING TO CONSTRUCTION ELEMENTS, ELECTRIC CONTROL, POWER SUPPLY, POWER SIGNAL OR TRANSMISSION, USER INTERFACES, MOUNTING OR COUPLING, DETAILS, ACCESSORIES, AUXILIARY OPERATIONS NOT OTHERWISE PROVIDED FOR, APPLICATION THEREOF

## Abstract

A control system for operating a bidirectional gate driven by a reversible electric motor includes an overload protection circuit to prevent motor current overload produced by gate obstructions and the like. The system includes control switches for operating gate opening and gate closing circuits which respectively energize the motor for rotation in opposite directions. The safety circuit includes a motor current sensing device and a first comparator which compares the level of sensed motor current with a temperature adjusted, selectable reference value and delivers a motor disabling signal to the opening and closing circuits if the sensed value exceeds the reference level. The safety circuit also includes a second comparator which compares the sensed current level with another reference value to produce the disabling signal in the event that the selected reference value of the first comparator is incorrect.

## Claims

### Claim 1

Apparatus for controlling the current delivered through an electrical motor, comprising:
means for producing a measured level of voltage proportionate to the magnitude of current flowing through said motor;
means for generating a first reference level of voltage;
means coupled with said producing means and said generating means for comparing the magnitude of said first reference level of voltage with said measured level of voltage and for producing a first output signal when said measured level exceeds said first reference level;
means for generating a second reference level of voltage;
means for comparing the magnitude of said second reference level of voltage with said measured level of voltage and for producing a second output signal when said measured level exceeds said second reference level; and,
means responsive to either of said first and second output signals for interrupting delivery of electrical current to said motor.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein said producing means includes a resistor adapted to be coupled between a source of electrical power and said motor.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein said producing means includes an electro-optical coupling device adapted to be coupled between a source of electrical power and said motor.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein said means for generating said first reference level includes means for manually adjusting said first reference level of voltage.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein said means for manually adjusting includes a manually variable resistance and said means for generating said first reference level further includes a comparator having a first input adapted to be coupled with a source of voltage and a second input adapted to be coupled with said means for manually adjusting.

### Claim 6 (depends on 3)

The apparatus of claim 3, wherein said producing means includes a comparator having an input coupled with said electro-optical coupling device and an output coupled with first comparing means.

### Claim 7 (depends on 6)

The apparatus of claim 6, including means for automatically adjusting said first reference level of voltage in response to changes in the ambient temperature, said means for automatically adjusting including a thermistor.

### Claim 8 (depends on 1)

The apparatus of claim 1, including means coupled with each of said comparing means for gating said first and second output signals.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein said gating means includes a OR gate coupled between said interrupting means and said first and second comparing means.

### Claim 10 (depends on 1)

The apparatus of claim 1, including means responsive to either of said first and second output signals for providing an indication that said measured level has exceeded one of said first and second reference levels.

### Claim 11 (depends on 1)

The apparatus of claim 1, wherein said interrupting means includes at least one bistable circuit element.

### Claim 12 (depends on 1)

The apparatus of claim 1, including a varistor element adapted to be coupled between said motor and a source of electrical power.

### Claim 13 (depends on 1)

The apparatus of claim 1, including means for inhibiting the delivery of said first output signal to said interrupting means for a preselected time period.

### Claim 14 (depends on 13)

The apparatus of claim 13, wherein said inhibiting means includes a capacitor.

### Claim 15

A control system for use with a bidirectional gate driven by a reversible electric motor, comprising:
selectively operable switch means for producing control signals to operate said gate;
means responsive to said control signals for selectively energizing said motor; and,
means for disabling said energizing means when the level of electrical current flowing through said motor exceeds a prescribed level, whereby to prevent current overload of said motor, said disabling means including
(1) means for producing a measured level of voltage proportionate to the magnitude of current flowing through said motor,
(2) means for generating a first reference level of voltage, said generating means including a first comparator having a pair of inputs, said producing means including a second comparator having an output,
(3) first means coupled with said producing means and said generating means for comparing the magnitude of said first reference level of voltage with said measured level of voltage and for producing a first output signal when said measured level exceeds said first reference level, and,
means responsive to said first output signal for interrupting the delivery of electrical current to said motor.

### Claim 16 (depends on 15)

The system of claim 15, wherein said disabling means includes temperature responsive means connected with said generating means for automatically adjusting said first reference level of voltage in response to changes in the ambient temperature.

### Claim 17 (depends on 15)

The system of claim 15, wherein said producing means includes a resistor adapted to be coupled between a source of electrical power and said motor.

### Claim 18 (depends on 15)

The system of claim 15, wherein said producing means includes an electro-optical coupling device adapted to be coupled between a source of electrical power and said motor.

### Claim 19 (depends on 15)

The system of claim 15, wherein said generating means includes means for manually adjusting said first reference level of voltage.

### Claim 20 (depends on 19)

The system of claim 19, wherein said means for manually adjusting includes a manually variable resistance.

### Claim 21 (depends on 15)

The system of claim 15, including temperature responsive means connected with said generating means for automatically adjusting said first reference level of voltage in response to changes in the ambient temperature, said means for automatically adjusting including a thermistor.

### Claim 22 (depends on 15)

The system of claim 15 including:
means for generating a second reference level of voltage; and,
means coupled with said producing means and said means for generating a second reference level for comparing the magnitude of said second reference level of voltage with said measured level of voltage and for producing a second output signal when said measured level exceeds said second reference level.

### Claim 23 (depends on 22)

The system of claim 22, including means coupled with said first and second comparing means for gating said first and second output signals.

### Claim 24 (depends on 23)

The system of claim 23, wherein said gating means includes an OR gate coupled between said interrupting means and said first and second comparing means.

### Claim 25 (depends on 15)

The system of claim 15, including means for inhibiting the delivery of said first output signal to said interrupting means for a preselected time period.

### Claim 26 (depends on 15)

The system of claim 15, wherein said energizing means includes:
a gate opening circuit having an output connected to said motor;
a gate closing circuit having an output connected to said motor; and,
circuit means coupled between said disabling means and said opening and closing circuits for controlling said gate opening and gate closing circuits.

### Claim 27 (depends on 26)

The system of claim 26, wherein said opening and closing circuits each include a bistable circuit element having a reset input under control of said disabling means.

### Claim 28 (depends on 27)

The system of claim 27, wherein said opening and closing circuits each include an electrical switch adapted to couple said motor with a source of electrical power and controlled by the corresponding bistable circuit element.