US 3543883 A
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United States Patent Inventor James H. Kuzara Toledo, Ohio Appl. No. 720,856 Filed April 12,1968 Patented Dec. 1, 1970 Assignee Reliance Electric Company Euclid, Ohio a corporation of Delaware FLOOR MAT PASSENGER COUNTER 7 Claims, 3 Drawing Figs.
U.S. Cl Int. Cl Field of Search References Cited UNITED STATES PATENTS 2,713,645 7/1955 Lerch l87/29X 3,168,164 2/1965 Kiely 187/29 Primary Examiner-Gris L. Rader Assistant Examiner-W. E. Duncanson, Jr. Attorney-Wilson & Fraser ABSTRACT: An electrical circuit for ascertaining the number of persons in a given floor area. The circuit is adapted particularly for passenger elevators where discrete pressure sensitive areas of the floor of an elevator cab actuate individual circuit sections to issue signals employed in either digital or analog form to indicate the loading of the elevator cab.
50% LOADED Patented Dec. 1, 1970 3,543,333
T DETECTO [201. LOADED 3 T 32 3 m DETEC-RDR [GOZLOADED INVENTOR. JAMES H. KUZARA w il) CROSS-REFERENCES TO RELATED APPLICATIONS The electrical circuits of this invention are particularly adapted for incorporation in an elevator supervisory control system of the type disclosed in U.S. Pat. application Ser. No. 493,973, filed Oct. 8, 1965 for Elevator Controls in the names of D. L. Hall and W. C. Susor, and Ser. No. 494,194 filed Oct. 8, 1965 for Elevator Controls in the names of D. L. Hall, W. C. Susor and J. H. Kuzara.
BACKGROUND OF THE INVENTION proaches have been less than satisfactory since they either have indicated but one level of loading, have not been of sufficient accuracy to indicate the several degrees of loading which can be employed significantly in the control of elevators, or have been too expensive both from a first cost and maintenance point of view to be economically feasible.
SUMMARY OF THE INVENTION This invention relates to automatic control mechanisms for sensing the number of persons in a given area and more par ticularly to apparatus for controlling an elevator system in accordance with the number of persons standing in a given area associated with the system.
An object of the invention is to improve the control of elevator systems.
Another object is to provide a precise count of the passengers or a measure of theload in a given area associated with an elevator system such as the cab of an elevator or in the landing area adjacent an elevator entry.
In accordance with the above objects a feature of this invention involves a flooring having pressure sensitive transducers responsive to loading of discrete floor areas to actuate subdivided circuits such that various degrees of loading density can be sensed. One embodiment employs normally open switches which close circuits through resistors connected in parallel to develop a signal which is a function of the number of floor areas loaded. Such a signal can be applied to comparator circuits which are responsive to signal levels representative of predetermined load levels as percent, 40, percent, 60 percent, 80 percent and 100 percent load for an elevator car. Alternative analog load signal systems can employ capacitive devices which respond to changes in the capacitance due to the presence of bodies above the floor area in which they are mounted.
Another arrangement providing digital count of loaded floor areas employs a counter which is triggered to scan all transducers for the floor areas in response to a given condition such as an open car door. A binary counter can be coupled to the transducers to receive a count for each loaded floor area. This binary count can be employed directly in the elevator system controls, or can be converted to a analog signal to provide a count of passengers. The signals can also indicate degrees of loading as by count threshold sensors or comparators.
DESCRIPTION OF THE-DRAWINGS FIG. 1 is a perspective of an elevator car including a floor having an array of load responsive areas providing signals'to the circuits of this invention;
FIG. 2 is a schematic diagram of an analog loadl signal system according to this invention; and t FIG. 3 is a schematic diagram of a digital load signal system according to this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 represents an elevator car 11 having side walls 13 and a segmented flooring 14 for the cab. Each segment 15 of the floor is arranged to close switch contacts 16 while subjected to a predetermined weight, e.g. 50 pounds, and to release those contacts to an open position when no such loading is imposed. Several commercial floor mat units are available to provide this mode of operation and therefore further details of the switch actuating segments is unnecessary for purposes of disclosing this invention.
An array of floor segments 15 for an analog load signal circuit load transducer is shown in FIG. 2 with each contact 16 connected between a common negative bus 17 coupled to a suitable source of electrical energy (not shown) and a resistor 18. All resistors 18 are connected in parallel to a bus 19 extending to the negative input terminal 21 of operational amplifier 22. Operational amplifier 22 has a resistance 23 connected between its positive terminal and ground to balance the source impedance on its inputs and a feedback resistance 24 between its output and its negative input to set its gain. Operational amplifier 22 issues a signal from its output on lead 25 which is a function of the number of switches 16 which are closed.
The signal on lead 25 is applied to load level detectors 26. A Schmitt trigger (not shown) which fires at zero voltage provides an excellent detector when provided with a presettable voltage level as from a potentiometer 27 connected from a negative source to ground and having a wiper 28 connected to the second input of the detector. The detector inputs are to a voltage divider arranged to compare the positive signal level on lead 25 with the negative signal level from wiper 28 and at a fixed intermediate point (not shown) issue a signal to the input of the Schmitt trigger in detector 26. Detector output 29 responds to a 20 percent loading of the elevator car and thus the setting of its potentiometer wiper 28 imposes only a small negative voltage on the divider of the detector which is overcome to fire the Schmitt trigger when a positive signal on lead 25 is representative of a 20 percent load. In a similar manner the output 31 responds to a 50 percent load and output 32 to an percent load by virtue of the settings of the wipers 28 of their respective detectors 26.
These load signals can be applied to perform switching operations as through operation of relays, electronic switches or solid state switches in conventional elevator supervisory controls. Alternatively, they can be applied through resistances to produce analog signals which can be utilized in the allotter of the above noted Hall, Susor and Kuzara patent application as an indication of service burden to be summed with other factors in making allotments between cars and hall calls.
FIG. 3 shows a digital system for measuring loading applied to an elevator system. A ring counter 35 arranged to advance a series of pulses to individual output terminals 36 and thereby scan the floor contacts 16 passes pulses through those contacts which are closed to a binary counter 37. The count of the floor switches in the binary counter read as an indication of car loading. This system as applied to an elevator car scans the floor of the car in this manner to continuously monitor the car loading while the car door is not closed. In the system of the Hall, Susor and Kuzara patent application noted above, where the allotments between hall calls and the cars are optimized to cause the car best situated to serve a call, to serve that call the continuous monitoring of the car loading during the interval the car doors are opened will result in decreases and increases in indicated service capacity as arriving passengers exit the car and intending passengers enter the car. Thus if an allotment is initiated during the initial portion of a stop where the car is unloading, the car will indicate a service capacity less than it actually has. Conversely if it is loading, it will indicate greater service capacity before the load enters than after loading is cause a reallotment of all hall calls for floors for which no car 7 call is registered in the car each time a passenger transfer occurs as indicated for example by the interruption of the beam of radiant energy projected across the door closing path of the car for door protection purposes.
A "door closed signal derived from a limit switch (not shown) when the door is fully closed is absent from lead 41 while the car door is open to cause inverter 42 to issue an enabling signal to AND 43. AND 43 is gated at the end of each ring counter scan by a signal from the last output 44 in the sequence of terminals 36 to enable ring counter 35 to institute a new scan. Ring counter 35 is of a nature such that a signal momentarily applied at lead 45 causes the counter to scan through all of its terminals hence upon initial opening of a car door the counter will have a signal on its last terminal 44 and respond immediately to the signal from inverter 42 through AND 43.
Contacts 16 of floor segments 15 are connected between each terminal of counter 35 and a common input lead 46. Each scan of the counter applies a pulse for each loaded floor segment 15 through coupling capacitor 47 to the first stage 48 of binary counter 37. Counter 37 is of the well-known type employing bistable flip flops for each stage wherein the state of a stage is inverted each time a pulse is applied to its input. The stages are arranged such that an output signal on lead 49 of the first stage 48 signifies a count of l on lead 51 from the second stage a count of 2," on lead 52 a count of 4" and on lead 53 a count of8. All stages are reset to a no count by a signal on reset lead 54.
In the scanning of the floor segment loadings by ring counter 35 the binary counter 37 will count through the number of loaded segments each scan. In order to retain the count of loading the load detectors are provided with flip flops for memories.
The illustrative system is arranged to issue signals for 25percent, 50 percent and 75 percent load from terminals55, 56 and 57 respectively. Twelve floor segments 15 have been shown for the elevator car floor. Three loaded pads represents a 25 percent load and causes binary counter 37 atsome time in each scan of counter 35 to issue a signal on leads 49 and 51. AND 58 is gated by a count of three through the coincidence of signals on leads 49 and 51 to trigger slave memory 59 to issue a signal on lead 61 to AND 62. In like manner a percent loading of the pads results in a binary count of six which imposes a signal on leads 5] and 52 to gate AND63 to slave memory 64 while a count of nine for 75 percent load gates AND 65 to memory 66 by the coincident'signals on leads 53 and 49 of binary counter 37 Continuous monitoring while the car door is open results from the scan advance of ring counter 35 through its final output terminal to gate AND 43 and start a new cycle. After each scan of the array of contacts 16 for floor segments 15 and the setting of the appropriate slave memories 59, 64 and 66 for the load and for levels less than the load for which memories are provided, the next step of the ring counter 35 imposes a signal on lead 54 to reset the stages of binary counter 37 and all master memories 68, 69 and 71 over their reset"inputs, eachof which is labled rs. Thus on each cycle of the ring counter 35 the load signal, as indicated by the signals on outputs 55, 56 and 57 of those memories which are set, is momentarily reset.
The next step of the ring counter 35 issues a signal to lead 72 to gate the "set" slave memories 59, 64 and 66 through the respective 'ANDs 62, 73 and 74 to the set'? inputs ofmaster.
memories 68, 69 and 71 each of which is labled s. ln this manner the master memories are cleared of the load signals for the preceeding scan of ring counter 35 and then set to the load registered in the slave memories for the current scan.
Slave memories 59, 64 and 66 are reset for each cycle of the ring counter 35 after they have set the master memories. They are thereby prepared to respond to a new load count of the next scan of the ring counter which may occur immediately if the door to the car is open or it the door has been closed, upon the opening of the door. Reset of the slave memories is by the pulse of ring counter 35 on lead 76 following the slave-tomaster gating pulse. This signal is applied to reset" inputs rs of slave memories 59, 64 and 66 immediately ahead of the final output signal of ring counter 35 as imposed on lead 44.
Ring counter 35 initiates a new cycle in response to the signal on lead 44 when it is coincident with a door closed not signal from inverter 42. Thus if the door is not closed at the end of its scan, ring counter 35 initiates a new scan. Scan cycles are continued in a sequence of the count of loaded floor pad segments ascertained by binary counter 37 and stored by slave memories 59, 64 and 66, followed by the reset of the binary counter 35 and the master memories 68, 69 and 71, then the gating of the slave memories into the master memories, then the reset of the slave memories, and then the issuance of an initiation signal for another scan, for each cycle throughout the door open interval whereby a continuous reading of the loading is represented by the signals on leads 55, 56 and 57. These loading signals can be employed in wither analog systems by suitable analog signal converters (not shown) or as digital signals issued directly from the leads.
It is to be appreciated that the disclosed systems lend themselves to measuring the density of loading of any given floor area. While the floor of an elevator car has been illustrated, it is evident that the region adjacent the elevator entry at a landing served by a car might have a load sensing system of this type to count the number of passengers to be anticipated or that other areas such as for loading other vehicles for passengers could employ the system. The useful output of the system is of wide scope including means responsive to a single threshold, to multiple threshold, or to a continuous range of load values, to actuate indicators or control elements. In an elevator system these utilizations can include indicators such as lamps on supervisory displays for given levels of loading, bypass controls responsive to load levels, and the call-car allottment controls referred to above.
In view of the variations of the elements of the system, its
, applications, and its functions, it is to be understood that the present disclosure is to be read as illustrative and not in a limiting sense.
1. Apparatus for measuring the density of population in a given floor area comprising a plurality of discrete floor sections, an electrical transducer associated with each floor section and responsive to the loading of said section, circuit means for generating a range of signals as a function of the 5 number of responsive transducers, and means responsive to each of a plurality of predetermined signals from said circuit a means.
2. A combination according to claim 1 wherein said floor area is the floor of an elevator car and including means responsive to a predetermined condition during operation of said elevator car to enable said circuit means, and means tion and responsive to the loading of said section, scanning means for issuing a signal serially from each of a plurality of outputs, means to connect an output of said scanning means to each of said transducers, and a counter for counting the number of transducers associated with loaded floor sections.
5. A combination according to claim 4 wherein said scanning means is a ring counter and said floor area is the floor of an elevator car having an entry and means closing said entry and including, means responsive to a given degree of closure of said entry closing means, and means to place said ring counter in operation when closure responsive means indicates said entry is open.
6. A combination according to claim 4 including means responsive to a predetermined count in said counter.
7. A combination according to claim 4 including a plurality of means each responsive to predetermined count in said counter for indicating a plurality of levels of loading of said floor area.