Electromagnetic latch retractor for exit bar
AssigneeHarrow Products, Inc.
InventorsGeorge Frolov, John E. Walsh, Leon Boiucaner
Life of this patent
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Abstract
A exit bar for securing a door has a housing adapted for mounting to a door. A push pad for receiving a push force is mounted to the housing. A latch extends from the housing to releasably latch the door to which the exit bar is mounted. A link system links the push pad to the latch so that a push force exerted on the push pad releases the latch. An electromagnetic disposed in the housing causes an armature to engage the link system to retract the latch. The exit bar further dogs the latch in the unlatched position as long as the power control system for the electromagnet receives an operate signal and for a preestablished delay time after the operate signal has been removed.
Claims18
An electromagnetic latch retractor for an exit bar mounted to a face of a door pivotally mounted in a door frame, the door frame including a latch strike, the exit bar including a housing adapted for mounting to the door face, a latch extending from the end of the housing proximate the latch strike for releasably latching the door, a push pad defining an exposed push face for receiving a push force, and a link system linking the pad to the latch for retracting the latch when the pad is pushed, the latch retractor comprising:
- an electromagnet mounted within the housing, the electromagnet having a magnetic face;
- power supply means for selectively supplying high voltage electrical power to the electromagnet;
- an armature having oppositely disposed proximal and distal ends, a distal end portion and an inboard surface disposed oppositely the magnetic face of the electromagnet, the armature being pivotally mounted to the housing at a position intermediate the proximal and distal ends of the armature, the distal end portion of the armature being engageable with the link system;
- and
- biasing means having a biasing force for biasing the proximal end of the armature toward the electromagnet and the distal end of the armature away from electromagnet, the inboard surface of the armature and the magnetic face of the electromagnet defining a wedge-shaped gap;
- wherein the electromagnet develops a high magnetic field when energized by the high voltage electrical power, the high magnetic field bridging at least a portion of the wedge-shaped gap and imposing a high magnetic force on the armature, the high magnetic force being greater than the biasing force, wherein the high magnetic force pushes the distal end of the armature toward the electromagnet and the distal end portion of the armature engages the link system and moves the link system to retract the latch.
An exit bar mounted to a face of a door having a power supply having a voltage, the exit bar comprising:
- a housing adapted for mounting to the door face;
- a latch extending from the housing for releasably latching the door;
- a push pad defining an exposed push face for receiving a push force;
- a link system linking the pad to the latch for retracting the latch when the pad is pushed;
- an electromagnet mounted within the housing, the electromagnet having a coil and a magnetic face;
- a power control system in electrical communication with the power supply and selectively supplying high or low voltage electrical power to the electromagnet;
- an armature having oppositely disposed first and second ends and an inboard surface disposed oppositely the magnetic face of the electromagnet, the armature being pivotally mounted within the housing at a position intermediate the first and second ends of the armature, the second end portion of the armature being engageable with the link system;
- and
- biasing means having a biasing force for biasing the first end of the armature into engagement with the electromagnet and the second end of the armature away from electromagnet, whereby the inboard surface of the armature and the magnetic face of the electromagnet define a wedge-shaped gap;
- wherein the electromagnet develops a high magnetic field when energized by the high voltage electrical power and a low magnetic field when energized by the low voltage electrical power, the high magnetic field bridging at least a portion of the wedge-shaped gap and imposing a magnetic force on the armature which is greater than the biasing force wherein the armature closes the gap and the inboard surface of the armature engages the magnetic face of the electromagnet and the second end of the armature engages the link system, moving the link system to retract the latch, and the low magnetic field electromagnetically bonds the armature to the electromagnet to support the latch in a dogged position.
Dependencies are inferred from the claim text.