Elevator – industrial lift truck – or stationary lift for vehicle – Stationary lift for roadway vehicle or required component... – Having specific drive means for support
Patent
1989-02-08
1990-12-11
Skaggs, H. Grant
Elevator, industrial lift truck, or stationary lift for vehicle
Stationary lift for roadway vehicle or required component...
Having specific drive means for support
187DIG1, 187104, 250221, B66B 1300
Patent
active
049763377
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to proximity detection systems and in particular, but not exclusively to door detection systems for elevator or lift doors.
Various devices have been proposed for preventing lift doors from closing or for causing lift doors to reverse, during closing, where an obstruction is sensed in the doorway.
With one type of device an array of beams is caused to traverse the opening between a lift door and its opposing slam post or between two synchronised lift doors aligned in the same plane to move towards, or away from, one another synchronously.
While such a device will detect an obstruction in the left door opening it cannot detect the presence of an obstruction in the opening of the corresponding landing doors, nor can it detect the approach of an obstruction to the opening. Thus for example fingers may be trapped between the landing doors as they close.
With another type of device, a capacitive or infra red detector is mounted along the edge of the or each lift door. Such detectors can detect the presence of obstructions both in the opening defined by the lift doors and in areas on opposite sides of the opening. The range of such devices is limited and so while obstructions are detected in the vicinity of the door edges, an obstruction in the centre of the opening is not detected until the doors have moved in closer to bring the obstruction into the range of the detectors.
Thus while these detectors are more efficient at detecting obstructions in, and close to, the lift door opening, the closing of the doors and the sudden opening of the doors when they approach an obstruction will tend to be unsettling for those users of the lift who may be infirm or of nervous disposition.
It is an object of the invention to provide an improved proximity detection system.
According to the invention there is provided a proximity detection system comprising a detection strip mountable adjacent the leading edge of door, the detection strip having two detection zones, a columnar zone extending parallel to the strip and arranged to be located immediately in front of the leading edge of the door, and a planar zone extending across any opening defined between the leading edge of the door and the opposing edge of the opening.
Preferably said two zones intersect one another.
According to the present invention there is further provided a proximity detection system comprising an optical line of sight detector, positioned adjacent one side of an opening in which detection is to take place, a capacitive detector having a capacitive plate or antenna of translucent electrically conductive material, located adjacent said one side of the opening between the line of sight detected and the said one side of the opening, so that optical transmission to or from the detector takes place through said capacitive plate.
Proximity detector system embodying the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:
FIG. 1 is a fragmentary perspective view of the proximity detector system with the cover partially removed;
FIG. 2 is a plan view of a lift car with the system of FIG. 1 mounted on opposing lift doors;
FIG. 3 is a cross-section through the system mounted on one door; and
FIG. 4 is a circuit diagram of the capacitive part of the door detector system.
As shown in FIG. 2, a lift or cabin 2 supports a pair of sliding car doors 4 and 6 which can be moved in synchronism towards or away from one another to close or open the opening. An elongate detector strip (8 and 10) is mounted on the outer face of respective car doors 4 and 6 adjacent the leading edges thereof. A pair of opposing landing walls 12 and 16 support respective ones of two sliding landing doors 14 and 18. The landing doors 14 and 18 are synchronised to open and close with the car doors 4 and 6 by control circuitry (not shown).
The detector strips 4 and 6 together define three separate regions in which detection of an obstruction can take place namely, a column like region 20 extendi
REFERENCES:
patent: 2149177 (1939-02-01), Miller
patent: 2900521 (1959-08-01), Eames
patent: 3370677 (1968-02-01), Federmann et al.
MOS FET Takes the Push out of Elevator Push Button, Fred G. Geil, Electronics, Oct. 30, 1967, pp. 70, 71.
Formula Systems Limited
Noland Kenneth
Skaggs H. Grant
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