Note: Descriptions are shown in the official language in which they were submitted.
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Aperture Closures
The present invention relates to aperture closures and in particular to
control arrangements for controlling aperture closure members such as doors.
In many situations, particularly industrial premises, it is known to
provide electrically driven doors to allow remote operation of the doors. It
is an
object of the present invention to provide an improved control arrangement for
aperture closure members of this general nature.
The invention provides an aperture closure member control arrangement
comprising electric drive means operable to drive the closure member, battery
supply means operable to power the control arrangement and comprising a
plurality of rechargeable cells, and power supply means operable to supply
recharging current to the cells, there being switch means associated with the
battery supply means and operable to connect the cells across the power supply
when the cells are being charged, and to connect the cells in series with each
other and with the drive means when powering the drive means.
The term "cell" is used because the "cells" can be connected together in
series to form a battery providing a higher voltage than the cells can provide
individually, but it is to be realised that each cell need not itself be a
single
voltaic cell, but could be in the form of a battery of several voltaic cells.
Thus,
the term "cell" is being used to refer to a module of one or more voltaic
cells.
Preferably each cell of the battery supply means comprises a first
terminal of a first polarity and a second terminal of a second polarity, the
terminals of the first cell being connected across the power supply means
during recharging, and the or each other cell having associated switch means
operable to connect the first terminal either to the first terminal of the
first cell
during charging, or to the second terminal of another cell to form a series
connection therewith when powering the drive means, and to connect the
second terminal to the power supply means during charging, the supply to the
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drive means being taken from the second terminal of a cell.
Preferably there are at least three cells connectable either across the
power supply during charging, or all in series while supplying the drive
means.
The switch means is preferably operable to connect the drive means between
the first terminal of the first cell and the second terminal of a selected
cell,
whereby the drive voltage is selectable.
The power supply means preferably comprises a power supply providing
regulated charging current. The charging current is preferably provided as the
collector-emitter current of an output transistor, regulation being achieved
by
adjustment of the base current. The collector-emitter current of the output
transistor is preferably in series with a resistor, the resistor and base
being
shunted by a control transistor, whereby base current of the output transistor
can be shunted by operation of the control transistor in dependence on the
current flowing in the resistor. The base of the control transistor is
preferably
connected to sense the output of the power supply, whereby to shunt base
current away from the output transistor, thereby turning off the transistor in
the event the output is shorted.
The power supply preferably provides voltage regulated charging current.
The charging current may be adjusted according to the output voltage to
control the output voltage. The output voltage is preferably applied to the
base
of a transistor circuit which supplies base current to the output transistor.
The
transistor circuit preferably compares the output voltage with a reference
voltage and adjusts the base current in accordance therewith.
The invention also provides an aperture closure member control
arrangement comprising drive means operable to drive the closure member,
and control means operable to count operations of the arrangement and to
modify operation in accordance with the count.
Preferably the drive means provides fast and slow modes for closing the
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closure member, the control means inhibiting fast closure after a
predetermined
numbers of counts has been reached. Preferably closure is effected by a manual
operation which is required to be more complex after a predetermined number
of counts has been reached. Operation to open the closure member is
preferably maintained without modification in accordance with the count.
The control means may effect a count of operations to determine when
maintenance of the arrangement is required, the control means providing a
manually detectable signal upon each operation after maintenance has been
determined to be required.
The control means may be responsive to a reset sequence of manual
operations to reverse the said modification to operation.
The invention also provides an aperture closure member control
arrangement comprising drive means operable to drive the closure member by
means of a rotating drive member and a drive belt, the drive means being
mounted on a carriage movable to bring the drive member and belt into and out
of engagement.
The carriage is preferably manually movable. The carriage may be
mounted to be pulled or released to bring the drive member and belt into and
out of engagement. The carriage may be provided with an elongate member by
which the carriage position may be controlled. The elongate member may be a
cable whose position is manually controlled by an over-centering mechanism by
which the cable may be tensioned to engage the drive member and belt, and
retained under tension.
The invention also provides an aperture closure member control
arrangement comprising drive means operable to drive the closure member,
and monitoring means operable to monitor variations in the load on the drive
means, the monitoring means comprising signal generating means operable to
provide first and second signals which vary in response to variations in the
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load, comparison means operable to compare the first and second signals, and
time
constant means operable to provide time constants which govern the responses
of the
signal generating means, the time constant means causing the second signal to
be
governed by a longer time constant than the first to cause the comparison
result to vary
in accordance with the rate of change of the load, and wherein limit means are
provided
to prevent the second signal passing a preset value.
Preferably the limit means provides an upper limit for the second signal. The
preset value may be a voltage level defined by a tap in a potential divider.
The second
signal is preferably provided to the comparison means at a point connected to
the
potential divider tap by means of a diode, whereby the second signal is
prevented from
passing the voltage at the tap by more than the forward bias voltage of the
diode.
Preferably at least one component of the potential divider is adjustable to
allow the
preset value to be changed.
Preferably the arrangement monitors motor current of an electric motor.
Accordingly, in one aspect, the present invention provides an aperture closure
member control arrangement comprising electric drive means operable to drive
the
closure member, battery supply means operable to power the control arrangement
and
comprising a plurality of rechargeable cells, and power supply means operable
to supply
recharging current to the cells, there being switch means associated with the
battery
supply means and operable to connect the cells in parallel across the power
supply when
the cells are being charged, and to connect the cells in series with each
other and with
the drive means when powering the drive means, each cell of the battery supply
means
comprising a first terminal of a first polarity and a second terminal of a
second polarity,
the terminals of a first cell being connected across the power supply means
during
recharging, and the or each other cell having associated switch means operable
to
connect the first terminal either to the first terminal of the first cell
during charging, or to
the second terminal of another cell to form a series connection therewith when
powering
the drive means, and to connect the second terminal to the power supply means
during
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charging, the supply to the drive means being taken from the second terminal
of a cell
selectable during operation of the arrangement to provide a selectable drive
voltage.
In a further aspect, the present invention provides an aperture closure member
control arrangement comprising drive means operable to drive the closure
member, and
control means operable to count number of times the arrangement has been
operated to
open or close the aperture closure member and to modify operation in
accordance with
the count.
In a still further aspect, the present invention provides an aperture closure
member control arrangement comprising drive means operable to drive the
closure
member by means of a rotating drive member and a drive belt, the drive means
being
mounted on a carriage movable to bring the drive member and belt into and out
of
engagement, the carriage having a mounting that allows free movement of the
carriage
during use of the arrangement, and there being control means which are
manually
operable to pull the carriage to a first position in which the drive member
and belt are in
engagement and to hold the carriage in said first position, or to release the
carriage
member to move to a second position in which the drive member and belt are out
of
engagement and the drive member is prevented from driving the drive belt.
Embodiments of the present invention will now be described in more detail, by
way of example only, and with reference to the accompanying drawings, in
which:
Fig. 1 is a highly schematic side elevation of a door closure arrangement
incorporating apparatus according to the present invention;
Fig. 2 is a partial and highly schematic rear elevation of the apparatus of
Fig. 1;
Fig. 3 is a rear elevation on an enlarged scale of part of the apparatus of
Fig. 2;
Fig. 4 is a schematic block diagram of control arrangements for the
CA 02338191 2001-09-10
apparatus of Figs. 1 to 3;
Fig. 5 is a simplified circuit diagram of a battery charging arrangement
within the circuit of Fig. 4; and
Fig. 6 is a simplified circuit diagram of a motor current tracking circuit
within the arrangement of Fig. 4.
Overview
The apparatus to be described below is described in use with a closure
arrangement in the form of an electrically driveable door which is articulated
to
allow the door to have a closed, vertical condition, and an open condition in
which the door extends generally horizontally over the opened aperture. The
arrangement could also be used with a door which remains in the same vertical
plane when open or closed, and which therefore need not be articulated.
Mechanical System
Figs. 1 and 2 show the sliding door mechanism schematically, with the
door partially open. The door 10 is in the form of a series of horizontal
slats,
each articulated to the slat above and below to allow the door 10 to move from
a closed position in a vertical plane, along between tracks 14 provided to
either
side of the door 10, until occupying an open position in a generally
horizontal
plane between the tracks 14. The horizontal leg of the tracks 14 is shown in
Fig. 1. The tracks have a vertical leg down a support post 15 but are not
shown
in Fig. 2, in the interests of clarity.
The door is moved by cables winding on or off a cable drum 12. The
drum 12 can be driven through a drive belt 16 and driven pulley 17 by an
electric motor at 18 and drive pulley 19. The motor 18 is under the control of
a
control circuit 20 which in turn is controlled by a manual control panel 22
and
powered by mains supply 24 or back-up batteries 26. The panel 22 may be
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connected by umbilical cable to the circuit 20, or may be a remote control
unit.
Both alternatives are illustrated in Figs. 1, 2 and 4.
Appropriate operation of the controls on the panel 22 instructs the
control circuit 20 to operate the motor 18 to turn the drum 12 in the
appropriate direction to drive the door 10 from the closed position to the
open
position, or from the open position to the closed position.
Belt drive arrangements such as that shown in Figs. 1 and 2 are known to
require periodic adjustment, for instance to take up any slack caused by
stretching of the belt 16. In accordance with the invention, provision for
this is
by mounting the motor 18 on a carriage 28 which is in turn slidably mounted at
30 on the post 15 to allow the carriage 28 to slide up or down. The slidable
mounting may be in the form of a track attached to the post 15, along which
the
carriage can slide. Other alternatives could be used, such as a slidable
mounting in the form of pegs (preferably on the post 15) slidable along slots
(preferably in the carriage). The arrangement used should allow movement to
change the tension in the drive belt 16, to allow sufficient slippage to
prevent
the motor 18 driving the drum 12. While up and down motion is described
herein, it will be apparent that any direction of motion could be used which
causes the motor to disengage from the drive belt.
The position of the carriage 28 is controlled by a cable 32 and lock
arrangement 34. Pulling down on the cable 32 will pull the carriage 28 down
and engage the motor 18 with the drive belt 16. Releasing the cable 32 will
allow the carriage 28 to ride up, removing tension from the drive belt 16 and
thus preventing the motor 18 from driving the drum 12.
The lock arrangement 34 includes an over-centering lever 36 to which
the cable 32 is attached and by means of which the cable can be pulled down to
snap the lever 36 over-centre to the position shown in broken lines (Fig. 3)
in
which the cable 32 is held under tension, pulling the motor 18 down. Manually
pulling the lever 36 up, over-centre, allows the cable tension to be released,
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disabling the door from further motor operation. This arrangement provides a
security feature, enabling authorised personnel to disable the arrangement,
thus
effectively locking the door in the current position (usually the closed
position).
Again, movement of the lever 36 could be in other orientations, with
appropriate routing of the cable 32.
Adjustment of the tension achieved in the cable 32 may be provided by
an appropriate screw-threaded or other adjustment between the cable 32 and
the lever 36.
Resilient members such as springs 19 are provided at the ends of the
tracks 14. These assist in starting movement of the door 10 from the open
position, to overcome mechanical problems such as friction, motor stalling and
the like. They also keep the cables taut on the drum 12. The door abuts the
springs 19 and compresses them as the door moves to the open condition.
Further details of this are set out below in connection with the motor current
tracking arrangement.
Operation of the door may be fast or slow. Preferably the door moves
fast until approaching the fully closed or fully open position, and then moves
slowly.
Electrical A.rrangements
Fig. 4 shows the electrical circuits of the arrangement in schematic block
diagram form.
Operation of the motor 18 is under control of a control circuit 20 which
is powered from mains 24 or by back-up batteries 26. A power supply circuit 38
also allows the batteries 26 to be charged. The control panel 22 includes
appropriate manual controls, preferably at least a minimum of three controls
to
instruct the door to open, to instruct the door to close, and to instruct the
door
to stop (for instance in emergency).
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Maintenance and Account Features
The basic operation of the control circuit 20 is to respond to activation
of the OPEN control on the panel 22 to drive the motor 18 to open the
associated door, and to reverse the direction of the motor 18 to close the
door
when the CLOSE control is activated. A STOP control may also be provided for
emergency use.
Each operation of the door is counted by the circuit 20, and the manner
in which the arrangement functions is modified in accordance with the count.
First, the circuit 20 (which may be microprocessor based, or use discrete
components, or a combination of both) stores a value for a predetermined count
and allows the door operation to continue normally until that count has been
reached. Thereafter, fast door operation is inhibited so that the door can
only
operate at a relatively slow speed. This predetermined count can be set to
correspond to a few weeks normal usage. This facility would be used by an
installer when the arrangement is first installed. By disabling fast operation
after a few weeks, the arrangement would appear to the user to be
malfunctioning once the predetermined count has been reached. The user is
then likely to contact the installer for further information or to complain.
This
allows the installer to ensure that the installation has been paid for, before
either attending to reset the count (or disable that facility), or issuing the
user
with a code sequence of control operations in order to disable that function.
In similar manner, the control circuit 20 continuously counts operations
of the door 10 in order to monitor maintenance intervals. A further
predetermined count is stored within the circuit 20, corresponding to normal
usage over a period normally of several months and corresponding to a typical
service interval. When the second predetermined count is reached, the operator
can be provided with a signal, such as a light, sound or other signal, to
alert the
operator that maintenance is desirable or required. The circuit 20 can be
arranged (such as by programming of a microprocessor or the like) to reset the
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count once a specified control sequence has been executed on the panel 20.
This sequence would normally be known only to the service or maintenance
engineer.
Battery Charging Supply
Fig. 5 shows those components of the circuit 20 involved in providing
charging current for the back-up batteries 26.
A power supply 40, toward the left of Fig. 5, provides a regulated supply
at point 42 when connected to a rectified mains supply at 44. The output
voltage at 42 is provided to the batteries through diodes D1,D2,D3, as will be
described.
Charging current is provided as collector-emitter current of transistor
TRl which provides current controlled by its base current. Base current can be
controlled to provide voltage regulation by means of an arrangement indicated
at 48. Resistors R1, R2 are in series between point 42 and ground to provide a
potential divider tapped to the base of transistor TR2. The emitter of TR2 is
held at a reference voltage by zener diode Zl. The collector of TR2 is
connected
to ground through a bias resistor R3, and to the base of TR3. The emitter of
TR3 is connected to ground, and the collector is connected to the base of TRl,
through series resistor R1 and annunciator diode D8.
Consequently, if the voltage at point 42 begins to rise, the base voltage of
TR2 will rise. This reduces emitter-collector current of TR2 which reduces the
base current of TR3, which in turn reduces the base current of TR1. This tends
to return the voltage at 42 to the original level. Similarly, if the voltage
drops,
the circuit just described will tend to return the voltage to the original
level.
Current limiting is provided by transistor TR4 and associated resistors,
as follows. A resistor RS is provided in series with the emitter of TR1 and
the
voltage across R5 is applied across the base emitter junction of TR4. The
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collector of TR4 is connected to the collector of TR3 through R4.
TR4 provides a clamp (that is, an upper limit) on current supplied at 42,
in the following manner. If the current rises sufficiently to cause the
voltage
across RS to be high enough to turn on TR4, base current to TRi will then tend
to shunt through TR4 to the supply at 44, rather than passing through TR1,
until output current is returned to the original value.
TR4 also provides protection against short circuit. This is achieved by R6
from the base of TR4 to point 42. Thus, if point 42 is shorted to ground, TR4
will turn fully on, shunting the base current of TRl, away from the base. TR1
will turn off. This arrangement can also provide trickle charge current to a
fully
discharged battery. Protection against reverse polarity connection of a
battery
is provided in similar fashion.
Battery Switchiml, Arran ements
Toward the right of Fig. 5, connections are shown for three batteries
26a,b,c. Each battery has positive and negative terminals which can be
connected together in various arrangements by a switch arrangement generally
at 52.
It is to be appreciated that when the supply 40 is operating (being
supplied by mains) the batteries 26 will not supply the motor 18 but may be
charged by the supply 40. When the supply 40 fails (particularly vvhen mains
is
removed) the batteries 26 can then power the motor 18.
The three batteries 26 include a first battery 26a having a negative
terminal 54a permanently connected to ground and a positive terminal 56a
permanently connected to the point 42 through diode Dl.
The second battery 26b has a negative terminal 54b connected through a
relay RLl either to the positive terminal of battery 26a, or to ground (the
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negative terminal of battery 26a), according to the setting of RLl.
The positive terminal of the second battery 26b is connected to point 42
through diode D2 and can be connected through relay RL2 to the negative
terminal of battery 26c. In the other position of RL2, the negative terminal
of
battery 26c is connected to ground. The positive terminal of battery 26c is
connected to point 42 through diode D3.
Accordingly, appropriate setting of the relays RL1,RL2 allows the
batteries 26 to be connected either across the supply 40 (between ground and
point 42) to allow them to be charged together, effectively in parallel, but
isolated from each other by diodes Dl,D2,D3. This provides efficient charging
while power supply 40 is operating normally. When power supply 40 fails
(because mains has failed), the relays RL1,RL2 trip to the position shown.
This
connects batteries 26a, 26c in series, as follows. With relays RL1,RL2 in the
positions shown in Fig. 5, the three batteries 26a,26b,26c are in series,
providing
three times the battery voltage to the output at 46, from the positive
terminal of
battery 26c, through diode D4. A tap of twice the battery voltage is available
from the positive terminal of battery 26b for use elsewhere in the control
arrangement. If RL2 then switches to the other position, batteries 26a,26c are
then in parallel (but isolated by diodes), providing lower voltage (slow
speed)
drive to the motor through diodes D4,D5, but batteries 26a, 26b remain in
series, providing the tap at twice the battery voltage.
Nlotor Current Sensing
Fig. 6 illustrates a circuit used to monitor the load on the motor 18, by
monitoring the motor current by means of the voltage across a resistor R7 in
series with the motor (at 60).
Nionitoring is provided by a comparison technique described in our
British Patent No. 2287369B. The voltage across R7 (representing the current
through the motor 18) is applied to one terminal of comparator 62 through
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series resistors R8, the common terminal of which is connected to ground
through capacitors Cl to provide a time constant (such as 110 milliseconds)
which causes a time delay in passing changes in the voltage across R7 to the
input of the comparator 62. This part of the circuit also provides some RC
filtering of transients.
The second input 72 of the comparator 62 is also provided with a voltage
ultimately derived from R7, but modified as follows. The voltage across R7 is
applied to a potential divider formed by resistors R9 in series, one of which
is
variable to change the voltage offset between the potential divider tap 64 and
the voltage across R7. The voltage at the tap 64 is applied to the second
input
of the comparator 62 through a series resistor R10 and that input is connected
to ground through capacitors C2 to provide a second time constant (such as 680
milliseconds) which is longer than the time constant provided by R8,C1.
Consequently, in normal use, variations in the motor current will cause
the voltage across R7 to vary and the voltage at the two inputs of the
comparator 62 will track each other but remain at a potential difference set
by
the potential divider R9. However, if the motor current rises suddenly (for
instance due to an obstruction), the voltage applied to the comparator 62
through R8,C1 may rise more rapidly than the tracking voltage through R10,C2
(by virtue of the time constant differences), causing the comparator output to
change and signal at 66 that an obstruction or other abnormality has occurred.
Sensitivity is determined by the choice of voltage offset and time constants.
Obstruction detection is most important during high speed closing. When the
door is opening, or moving slowly, inputs OPEN or SLOW go high, putting more
current through the lower part of the offset potential divider R9, thus
reducing
sensitivity by increasing the offset voltage.
In this embodiment, an additional facility is provided by a clamping
arrangement at 68. This includes series resistors R11 and a variable resistor
R12, also in series, connected to the collector of TRS, the emitter of which
is
connected to ground. Two control lines labelled CLOSE and OPEN allow the
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control circuit 20 to turn TR5 on when the door is being opened or closed, by
applying base current through R13 or R14.
The potential divider R11,R12 is tapped at 70 and connected to the
tracking terminal 72 of the comparator 62 through diode D6. The tap 70 forms
a reference voltage which would be set higher than the expected peak value at
72 while the door is opening or closing. However, if the voltage at 72 was to
rise above the voltage at 70 by more than the forward bias voltage of diode
D6,
diode D6 would turn on and prevent the voltage at 72 rising any further,
clamping that voltage to the level set by the tap 70 and the forward bias
diode
voltage.
This facility provides an upper limit to the voltage at 72 and provides a
number of advantages. In particular, when the door is approaching the fully
open position, both inputs OPEN and SLOW will be high, and the sensitivity
will
be much reduced. This could give rise to very high motor currents, as the
springs 19 begin to be compressed, providing resistance to the motor and
tending to cause the motor current to rise steadily, not fast enough to
trigger
the comparator. Nfotor current will continue to rise until the voltage at 72
becomes clamped through diode D6, the comparator 62 signals an abnormality
and the motor is turned off. The point at which this occurs can be set by
adjustment of R12 and this in turn determines the degree to which the springs
19 will be compressed before the motor is turned off. Thus, the force with
which the springs 19 are pushing the door 10 away from the fully open position
is set by R12. During installation, R12 can be adjusted so that when the door
10
is fully open, the springs 19 provide adequate force to overcome initial
stalling
or inertia when the door is to close, as described above, and also to keep
cables
taut.
The clamping provided by diode D6 also provides an additional safety
feature in that if a "soft" obstruction is encountered, motor current might
not
rise sufficiently quickly for the time constant circuits to signal an
obstruction in
the manner described above, but if the door continued to move against an
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obstruction for this reason, the clamping of terminal 72 would eventually
function and cause the obstruction to be signalled.
Protection against motor start transients is provided as follows. Initially,
capacitor C2 will be fully charged through resistors R9,R10 and diode D7 prior
to operation beginning. When OPEN or CLOSE go high, to commence door
movement, transistor TRS begins to turn on. The speed of TRS turning on is
controlled by the time constant set by R13 or R14 and the capacitor C3 across
the base-collector junction of TRS. This limits the rate at which TR5 turns
on,
thus allowing motor start transients to decay (within about 220 ms). As TRS
turns on, D6 becomes forward biased, ensuring capacitor C2 will discharge
significantly to commence the tracking operation described above. The overall
effect is to prevent the comparator changing state until transients have
decayed, but to allow tracking to begin sooner than the time constant R10,C2
(about 680 ms) would allow.
Many variations and modifications can be made to the apparatus
described above, without departing from the scope of the invention. In
particular, component values and technologies can be widely varied in
accordance with the normal factors known to the skilled person.
Whilst endeavouring in the foregoing specification to draw attention to
those features of the invention believed to be of particular importance it
should
be understood that the Applicant claims protection in respect of any
patentable
feature or combination of features hereinbefore referred to and/or shown in
the
drawings whether or not particular emphasis has been placed thereon.
