Barrier operator having system for detecting attempted forced entry

• US 5,780,987 A
• Filed: 07/07/1997
• Issued: 07/14/1998
• Est. Priority Date: 05/17/1995
• Status: Expired

• Current Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Original Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Inventors: Fitzgibbon, James J., Moravec, John V.
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US08/888,836
• Time in Patent Office: 372 Days
• Field of Search: 318/16, 318/264, 318/265, 318/266, 318/286, 318/466, 318/467, 318/468, 318/469, 318/480, 49/25, 49/26
• US Class Current: 318/466
• CPC Class Codes: E05F 15/00 Power-operated mechanisms for wings motor-operated accessories in locks for completing closing or initiating opening of a wing E05B17/00
• CPC Class Codes: E05F 15/43 responsive to disruption of energy beams, e.g. light or sound
• CPC Class Codes: E05F 15/668 for overhead wings
• CPC Class Codes: E05F 2015/434 with cameras or optical sensors
• CPC Class Codes: E05Y 2201/41 for closing
• CPC Class Codes: E05Y 2201/434 Electromotors; Details thereof
• CPC Class Codes: E05Y 2400/51 of position, of back drive
• CPC Class Codes: E05Y 2400/81 User displays
• CPC Class Codes: E05Y 2800/106 Lighting
• CPC Class Codes: E05Y 2800/252 the elements functioning only in case of emergency
• CPC Class Codes: E05Y 2800/426 against unauthorised use E05Y2400/51, E05Y2400/522 take precedence
• CPC Class Codes: E05Y 2900/106 for garages

Abstract

A movable barrier or garage door operator has a barrier drive for moving the movable barrier or garage door between open and closed positions. Motion of the barrier is detected by a tachometer connected to the barrier drive or by upper and lower barrier travel limit switches. A test is made to determine if the barrier has been commanded to be in a closed state and to determine if a preselected time interval has elapsed following closure of the barrier. When both of those conditions are present and the door is moved upward without authorization an alarm signal is generated and can signal the barrier drive to apply a closing force. The timer prevents the barrier from being closed on a person or obstacle during normal operation and prevents injury. An obstacle detector also prevents unwanted closure on an obstacle.

Claims

1. A barrier operator for opening and closing a movable barrier, comprising:

a barrier drive;

means for detecting motion of the movable barrier;

means for detecting when a barrier command signal has been given to the barrier drive;

means for storing a commanded state of the barrier drive;

means for comparing the commanded state with the motion indicated by said barrier motion detection means, and for indicating if the motion conflicts with the commanded state; and

means for generating an alarm signal in response to the conflict indication of said comparing means.

2. A barrier operator for opening and closing a movable barrier according to claim 1, further comprising means for enabling the alarm signal generating means a preselected time interval following closure of the barrier.

3. A barrier operator for opening and closing a movable barrier according to claim 2, further comprising means for optically detecting the presence of an obstacle adjacent the barrier and producing an obstacle detection signal in response thereto, said obstacle detection means being inhibited in response to the means for enabling alarm signal generation.

4. A barrier operator for opening and closing a movable barrier according to claim 1, further comprising a barrier position detection switch for generating a barrier closure signal when the barrier is substantially closed and providing the barrier closure signal to the means for generating the alarm signal indicative of the fact that the barrier has been closed.

5. A barrier operator for opening and closing a movable barrier according to claim 1, further comprising means for causing the barrier drive to supply a closing force to the movable barrier in response to the alarm signal from the means for generating the alarm signal.

6. A barrier operator for opening and closing a movable barrier according to claim 5, further comprising means for the barrier drive to cease supplying a closing force after a predetermined time interval.

7. A barrier operator for controlling a movable barrier, comprising,

a down limit detector disposed to indicate whether said barrier is at a closed position or not;

memory means for storing one of a set of states of said barrier, the set of states including a CLOSED state indicating said barrier is closed;

alarm generation means, responsive to the barrier state stored by said memory means and said down limit detector, for generating an alarm signal when the stored barrier state is CLOSED and said down limit detector indicates said barrier is not at a closed position; and

alarm enabling means for enabling said alarm generation means a preselected time interval after said barrier is closed.

8. A barrier operator according to claim 7, wherein said alarm enabling means is responsive to an indication from said down limit detector that said barrier is closed for initiating the preselected time interval.

9. A barrier operator according to claim 7, further comprising:

down motor signal means, for providing a down motor signal in response to said alarm signal; and

a barrier drive responsive to said down motor signal for closing said barrier.

10. A barrier operator according to claim 9, further comprising:

obstacle detector for detecting an obstacle to movement of said barrier, and for generating an obstacle signal in response thereto; and

means for disabling said barrier drive in response to the obstacle signal.

11. A barrier operator according to claim 10, wherein said obstacle detector comprises:

an optical light emitter for emitting light; and

an optical light detector for receiving the light from said emitter, and generating a signal indicative of whether light is received from said emitter or not.

12. A barrier operator according to claim 9, wherein said alarm enabling means is disposed to continuously enable without a preselected time delay said alarm generation means after said alarm generation means has generated an alarm signal, and after said barrier drive has closed said barrier in response to said alarm signal.

13. A barrier operator according to claim 9, further comprising:

a barrier drive motion detector for detecting actual motion of said barrier drive and generating a motion signal indicative thereof;

wherein

said alarm generation means receives the motion signal and generates the alarm signal when the stored barrier state is CLOSED, said down limit detector indicates said barrier is not at a closed position, and said motion detector indicates motion of said barrier drive.

14. A barrier operator according to claim 9, further comprising:

a command signal receiver for receiving a signal commanding said barrier to open, and generating an indication thereof; and

means for providing an up motor signal in response to the receiver indication;

wherein

said barrier drive responds to the up motor signal by opening said barrier; and

said memory means stores a state selected from the set of barrier states, other than the CLOSED state, in response to the receiver indication.

15. A garage door operator for opening and closing a garage door, comprising:

a motor for moving the garage door;

a down limit detector, for indicating when the garage door is moved to a closed position by said motor;

timer means enabled by the indication from said down limit detector that the garage door is closed, disposed to indicate when a preselected interval has expired;

command signal means for receiving a commanded state of the garage door; and

a microprocessor responsive to said command signal means for causing said motor to move the garage door to the commanded state, disposed to cause the motor to close the garage door when said timer means indicates the preselected interval has expired, said down limit detector indicates the garage door is not closed, and said command signal means has not received a new commanded state.

16. A garage door operator according to claim 15, further comprising:

a tachometer for detecting rotation of said motor, and for providing an indication thereof to said microprocessor, wherein

said microprocessor is disposed to cause said motor to close the garage door when said timer means indicates the preselected interval has expired, said tachometer indicates said motor has rotated beyond a preselected threshold, and said command signal means has not received a new commanded state.

17. A garage door operator according to claim 15, further comprising:

an optical obstacle detector, for optically detecting the presence of an obstacle adjacent the garage door and producing an obstacle detection signal in response thereto, wherein

said microprocessor is responsive to the obstacle detection signal to cease causing said motor to close the garage door.

18. A garage door operator according to claim 15, wherein said command signal means comprises a radio frequency receiver.