US 6,091,217 AGranted

Safety gate operator which prevents entrapment, and method of its operation

AssigneeElite Access Systems, Inc.

InventorWalter Parsadayan

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Abstract

An automatic gate operator includes an electric drive motor coupled by a drive train to a movable gate, and includes provisions for sensing an actual or impending obstruction or blockage of the movement of the gate by a human, object, or animal, for example. In response to such an actual or impending blocking of the gate's movement, the drive motor is shut off and the gate is braked to a stop. Then the gate is reversed to move a short distance away from the actual or impending blockage or obstruction, and is braked again to a stop. Next, the gate is freed from its connection with the drive motor, allowing manual movement of the gate to allow clearance of the actual or impending blockage or obstruction from the path of the gate. This stop-reverse-stop-release sequence of movements for the gate may release any entrapped person or object which may have been contacted by the moving gate. Also, after the gate is released for free movement it can be moved manually. This release of the gate allows an entangled person, object, or animal to free themselves, or to be freed by a bystander, for example. The gate operator also includes a control circuit which senses traffic conditions and responds by incrementing or decrementing a timer which controls a pause interval of the gate in its fully-opened position.

A safety gate operator for moving a gate between opened and closed positions, said gate operator comprising:

a base member
an electric motor and motor controller circuit;
a speed reduction power train carried on said base member and coupling said electric motor to said gate to move the gate between opened and closed positions;
a gate position sensor providing a signal indicative of gate position;
a safety means during operation of said electric motor sensing at least one event selected from the group consisting of:
approach of a vehicle to the gate opening,
contact of the gate with an object or with a person, and
movement of an object or person into the gate opening, said safety means responsively providing a safety signal;
a brake effective when applied to stop movement of said gate;
said speed reduction power train including a clutch coupling power from said electric motor to said gate, and when disconnected allowing movement of said gate without back driving of said electric motor while still providing responsive movement of said gate movement sensor;
a control system including a memory facility;
and said control system including logic for in response to said safety signal sequentially:
stopping operation of said electric motor,
applying said brake to stop movement of said gate;
then operating said electric motor in a reverse direction only momentarily to move the gate in a reverse direction, and then
again stopping operation of said electric motor and again applying said brake to stop the gate for a second time;
the gate operator further including a clutch/brake assembly including both said brake and said clutch;
wherein said speed reduction power train includes an output shaft, said clutch/brake assembly including an electromagnetic brake unit having an electromagnetic anchor member secured for torque reaction to said base member, and said electromagnetic brake unit also having an armature carried on said output shaft.

15 more elements

Facts

Application

09/015,810Filed 29 Jan 1998

Granted

18 Jul 2000

Term ends

Not estimatedThe source records don’t support an estimate.

Classification12 codes

E05F 15/41
Safety devices, e.g. detection of obstructions or end positions: detection by monitoring transmitted force or torque ; Safety couplings with…
E05F 15/40
Power-operated mechanisms for wings: safety devices, e.g. detection of obstructions or end positions
E05F 15/42
Safety devices, e.g. detection of obstructions or end positions: detection using safety edges
E05F 15/643
For horizontally-sliding wings: operated by flexible elongated pulling elements, e.g. belts, chains or cables

Abstract

Claims12