Conveyors: power-driven – Conveyor or accessory therefor specialized to convey people – With means to control the operation of the section
Reexamination Certificate
1999-06-01
2001-06-05
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor or accessory therefor specialized to convey people
With means to control the operation of the section
Reexamination Certificate
active
06241070
ABSTRACT:
The present invention relates to systems for the conveyance of standing passengers, such as moving walkways and escalators.
Conventional walkway systems consist of ribbed belts, and conventional escalators consist of ribbed platforms to enable the use of a comb arrangement at the end of the walkway or escalator to bridge the gap with the termination plate to provide transition from the moving walkway or escalator onto the termination plate without ingestion of parts of the passenger's body, clothing, or other objects between the walkway or escalator and the termination plate. This method has been widely used throughout the world for many years. However the use of the rib and comb arrangement is not a fully satisfactory solution to the difficulties of achieving safe transition at the end of the moving walkway or escalator. For practical operation the comb teeth cannot mesh too closely with the ribs, gaps of 2 and 4 mm being common, and as a result, ingestion of passenger's clothing has occurred in some circumstances. Also the comb teeth are, by design, of relatively fragile construction so that if entrapment does occur, for example with a lace of a passenger's shoe, the teeth will break off rather than bend upwardly which would create a very dangerous obstruction. A significant problem arises when a tooth breaks off and leaves a gap into which, for example, a child's finger may intrude and be sheared off by movement of the travelling surface passing beneath the plate. There are a number of recorded instances of injuries occurring in this way. This is a potentially serious problem as replacement of broken teeth cannot be immediate.
The problem of comb teeth entrapment has been approached in conventional systems by making the termination plate movable in the direction of travel. Movement of the plate causes a switch to be tripped, which in turn stops the system. The problem is that the plate has to withstand, for example, the impact of an 80 kg man running onto it, without moving and causing the system to stop unnecessarily. The safety device is therefore necessarily insensitive, and this causes many problems.
Our earlier International patent application No. PCT/AU92/00163 provides a solution to the serious problem of entrapment between the surface of a moving walkway and a termination plate by using a flat belt entrained around a relatively small diameter roller at the end of the run of the belt. A critical relationship exists between the belt speed, roller diameter and position of the termination plate to ensure that successful transition will occur from the moving belt onto the stationary termination plate. However, in rare and unusual circumstances it might be possible for part of the clothing of a child sitting on the belt to enter into the gap between the termination plate and the belt. Our earlier patent application discloses a special shaping for the edge of the termination plate to facilitate removal in the unlikely event that ingestion occurs. The embodiment of
FIG. 2
of this earlier application includes the use of a secondary plate, subject to a light spring bias, beneath the edge of the termination plate to block the gap with the edge of the belt in order to make ingestion even more unlikely. If, however, material is ingested between the moving belt and the lightly biased secondary plate, ingestion forces are small and extraction of the material is easy. If a sufficient body of material is ingested to displace the lower plate sufficiently to allow ingestion to take place between the moving belt and the termination plate the ingestion force will rise abruptly and extraction would become difficult to impossible. However, before this situation arises movement of the secondary plate initiates shut down of the system.
The termination plate arrangement disclosed in our earlier International patent application PCT/AU92/00163 is specific to a walkway system involving a flat belt and small diameter rollers. A termination plate arrangement in accordance with a first aspect of the present invention is applicable to a wider range of passenger conveyance systems. Specifically it is applicable to walkway systems using belts which pass over small or larger diameter end rollers, walkway systems comprising rigid pallets, and also to escalators.
Another potential safety problem which exists with moving walkways or escalators arises if the system is blocked or partially blocked at its discharge end by stationary objects or a stationary passenger. Such a situation can arise, for example, if luggage has fallen down an escalator or ramped walkway and accumulates at the termination plate at the end of the system. With existing systems involving the use of a rib and comb arrangements as discussed previously, a similar danger can also arise if a passenger is trapped by the termination plate. This type of situation is potentially quite dangerous as the continually moving walkway or escalator will continue to deliver further passengers to the zone where the blockage exists therefore compounding the potential problem. Although all escalators and walkways should be equipped with an emergency stop button, nevertheless it is likely that action to stop the walkway or escalator will not occur until there has been observation that a dangerous blockage has arisen and it is possible that appropriate action may not be taken to stop the system until some passengers have already suffered injury as a result of the blockage.
A second aspect of the invention therefore relates to the detection of relatively stationary objects or persons within the system. This aspect of the invention is applicable to all forms of walkway systems and escalators, including systems whose surface is formed by a series of small rollers closely adjoining each other, and existing walkway systems and escalators with ribbed or flat belts and platforms, as well as walkways or escalators in accordance with the first aspect of the invention.
According to the first aspect of the invention, there is provided a system for the conveyance of standing passengers comprising means defining a travelling surface of the system and a termination plate associated with the travelling surface, the termination plate having a leading edge which lies closely adjacent to the traveling surface at a position at which a passenger is discharged from the travelling surface, and detector means responsive to the sensing of matter ingested between the leading edge of the termination plate and the travelling surface whereby to stop movement of the surface in the event that ingestion of matter into a position adjacent the underside of the leading edge is detected.
Preferred embodiments in accordance with the first aspect of the invention thus incorporate means to detect the intrusion of material under the leading edge of the termination plate, and to then stop the system to allow any trapped material to be withdrawn. In practice, the plate will be mounted so that its leading edge is positioned as close to the moving surface as is practical, and generally within one to two millimeters.
The plate can be pivotally mounted so that when the system has come to a stop the plate may be lifted to allow any ingested material to be easily removed. The plate should be prevented from moving before the system stops as this would not only allow the greater ingestion of flexible material, but could result in the ingestion of solid objects such as the fingers of a child passenger, and could also—in the case of a lifting plate—provide an added obstruction to passengers being propelled off the preceding moving part of the system.
The detector means may comprise contact-sensing means such as a finger, bar, wire, rod or plate which is depressed or otherwise displaced by the ingested material, or non-contact sensing means such as a beam emitted by a light emitting diode, a filament lamp or a laser diode and which is interrupted by the presence of ingested material, or a switch which operates by detecting change of capacitance as a result of ingestion of material.
Ac
Bidwell James R.
Loderway Pty. Limited
Seed IP Law Group PLLC
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