Note: Descriptions are shown in the official language in which they were submitted.
~23~8
-- 1 --
"Lever lock sa~e-ty device"
This invention relates to the field oE loc~cs of
the kind in which a movable bolt is retained in its
locking position by at least one movable locking member
05 which normally assumes a rest condition in which it
engages with the bolt to prevent its movement, but ean
be moved out of the rest condition to a bolt-release
condition by rotation of a key having an appropriate
key-bit shaped to coact with the locking member. The
invention has particular, but not exclusive,
applieation to lever locks in which a set of key levers
retain the bolt in its locking position.
It is desirable under certain circumstances to
have loeks, sueh as safe locks and vault loeks,
eontrolled on a timed basis, so that the loek eannot be
opened even with the proper key unless the timing means
has reached a predetermined "open" period. Ilowever, the
fixing of predetermined "open" periods ean be awkward
for the user who desires nccess at random times. For
~0 avoiding this disadvnn-tage, lt ls alr~ndy Icn{)wn to have
a saeety device, for attnchmellt to or incorporation in
a lever lock, in which a certain relatively short delay
(between insertion Oe the key and capability of opening
the lock) is obtained by means of a clockwork-operated
latching mechanism which is wound up by rotation of the
7a~8
-- 2 --
key in the lock.
The object of the present invention is to provide
an improved safety timer device, ~rimarily for a lever
lock, which permits inter alia of (i) having the
05 ~delay" period commenced (or re-commenced)
automatically at each time of insertion of the key,
(ii) completely immobilising the key levers or other
locking member(s) at all times other than during an
~open~ period which follows the ~delay~ period, and
(iii) wider variation of the ~delay~ period than
provided by the known clockwork-operated latching
mechanism.
According to a first aspect of the present
invention, there is provided a key-operable lock having
a movable ~olt which is retained in its locking
position by at least one movable locking member
engaging the bolt but movable by rotation of a coacting
key-bit of the key to release the bolt for movement to
an unlocking position, wherein the lock further
comprises a latching bar movable along a guide
extending laterally of the bar between a latching
position, in which the latching bar extends across the
path of movement of the locking member to act as an
abutment preventing movement of the locking member to
release the bolt, and an unlatching position;
latch-control means acting on the latching bar to move
.
~ 23~)'7~8
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said bar from its latching to its unlatching position;
switch means operable by movement of the key in the
lock; and a timer actuated by the ~witch means and
acting on the latch-control means to cause movement of
05 the latching bar from its latching position to its
unlatching~position after a delay following loperation
of the switch means.
According to a second aspect of the present
invention there is provided a lock control device for
10 attachment to a key-operable lock having a movable bolt
which is retained in its locking posi~ion by at least
one vable locking member engaging the bolt but
movable by rotation of a coacting key-bit of the key to
release the bolt for movement to an unlocking position~
lS said device compri~ing attachment means for securing
the device to the lock; a latching bar adapted to
extend into the lock and movable along a guide
extending laterally of the bar between a latching
position, in which the latching bar extends across the
path of movement of the locking member to act as an
abutment preventing movement o the locking member to
release the bolt, and an unlatching position;
latch-control means acting on the latching bar to move
said bar from its latching to its unlatching position;
switch means adapted to be operated by movement of the
key in the lock; and a timer actuated by the switch
L8
-- 4 --
means and acting on the latch~control means to cause
movement of the latching member from its latched
position to i~s unlatched position after a delay
following operation of the switch means.
05 As mentioned previously, the invention has
particular application to lever locks, in which a set
cf key levers constitute the at least one locking
member and serve to retain the bolt in its locking
position. This type of lock is widely used to secure
safes, vaults, strong rooms and the like high security
zones.
Usually, the locking member will be resiliently
biassed into its latching position by, for example, a
helical tension spring or a torsion coil spring.
Advantageously, the bar also extends across the
path of movement of the locking member when it is in
its unlatching position and the guide extends beyond
the unlatching position of the bar to permit further
movement of the bar with the locking member as the
latter moves to its unlocked position.
Suitably, the guide L-~ L-shaped and the bar in its
unlatching position i~ at the junction of the guide
limbs. The guide conveniently can be a slot provided
in a wall of the lock casing.
Preferably, the latch-control means is
electrically powered and usually will comprise a
5 ~3~7~
solenoid in an electrical circuit with the switch means
and the timer. It is also preferred tha~ the latch-
control means is time-controlled so that it retains the
latching member in its unlatching position only for a
05 predetermined time interval, e.g. 30 seconds to 3
minutes and thereafter allows or causes said member to
return to its latched position. In order to reduce the
risk of burning out electrically powered mean~ such as
the solenoid during such time interval, provision can
be made to reduce the voltage applied from an operating
voltage, e.g. 24 volts, to a holding voltage, e.g. 9-12
volts.
In a preferred embodiment of the invention, the
latch-control means comprises a solenoid as
aforementioned and the solenoid is articulately
connected to the bar by a connecting rod which extends
substantially perpendicularly from the bar.
A further switch means actuable upon movement of
the locking member to its unlocking position
advantageously may be provided to break the electrlcal
power supply circuit to the latch-control mean~.
Suitably, said switch means is actuated by movement of
the latching bar to a position beyond its unlatching
position and corresponding to the unlocked position of
the locking member.
The key-operated switch means may be actuated by
- 6 - ~3~7~8
rotation of the key in the lock but preferably is
actuated by insertion of the key. Suita~ly such switch
means has an actuator aligned with the rod of the key
and arranged to actuate the switch upon full insertion
05 of the key into the lock.
In order that the nature of the invention may be
readily ascertained, embodiments of a lock of the
present invention are hereinafter particularly
described with reference to the Figures of the
accompanying drawings. In the drawings:-
Fig. 1 is a view on the line I-I of Fig. 2 of a
lock in accordance with one embodiment of the
invention;
Fig. 2 is an end elevation of the lock of Fig. 1
15- from which some parts have béen omitted for clarity;
Fig. 3 is a plan view of the lock of Pig. 1 from
which some parts have been omitted for clarity;
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-- 7 ~
Fig. 4 is a view on the line IV-IV of Fig. 5 of a
lock in accordance with another embodiment of the
invention;
Fig. 5 is a plan view of the lock of Fig. 4 from
05 which some parts have been omitted for clarity;
Fig. 6 is an end elevation Oe lock of Fig. 4 from
which some parts have been omitted for clarity.
Fig. 7 is a detail sectional view, to an enlarged
scale, of the key-operated switch means of the lock of
Fig. 4;
Fig. 8 is a circuit diagram of a first arrangement
for control of the solenoid of the locks of Figs. 1 and
4;
Fig. 9 is a circuit diagram of a second
arrangement for said control which includes provision
for inserting, into the time delay, one or more periods
of 24 hours, as well as the normal time delay;
Fig. 10 is a functional diagram of the circuit of
Fig. 9;
Fig. 11 is a perspective view of part of a lock in
accordance with a further embodiment Oe the invention;
and
Fig. I2 is a view corresponding to F'ig. 11 but
Wittl an outer wall removed.
~5 The lock illustrated in Figs. 1-3 comprises a lock
body 1 having in one end wall a passage 2 in which a
~3~7~8
bolt 3 can slide into withdrawn and projecting
positions, corresponding respectively to unlocked and
locked states of the article, such as a safe door, on
which -the lock is mounted. In these figures, the bolt 3
~5 is seen in its projecting position. The lock mechanism
is conventional, to the extent that it includes a
plurality of levers 5 which are pivotable about a shaft
4 and which in their rest (i.e. horlzontal) position
engage with respective internal portions of the bolt 3
to retain the bolt in locked or unlocked position. The
levers are raisable, about their pivot axis, by means
of a key 6 having the usual shaft 7 on which is
provided the usual key-bit having projections ot`
different radial heights adapted to cooperate each with
a respective lever. The end of the key shaft projects
at 7a through the lock body 1. The operation of the
lock is normal, in that rotation of the key tbrough
approximately 180- causes lifting of the levers to
enable the bolt to be slid into the withdrawn or
protruding position.
~ support plate 8 is mo~ tefl at a splLcint~ troln the
rear face ~E the lock body I by ~our pil]ars ~, on]y
one of which is shown t`or clarity in l~'igllres ~ and 3.
In the rear face of the lock body (see i~ig. 1) there is
~5 provided an L-shaped guide aperture 10, the foot zone
or limb 10a of which corresponds with the position of
~;~30~
g
tlle upper surface of the levers 5 before they have been
raised by the key-bit. A similar guide aperture 11 is
provided in the support plate 8, in alignment with the
aperture 10. ~ latching bar 12 is positioned with one
05 end engaged through aperture 10 into the lock body 1 so
as to closely overlie all of the levers 5, and with its
other end projecting through aperture 11 of the
support plate 8. The latching bar is urged down-
wardly by a spring 13 engaged at its lower end on
a fixed stud 14 on the support plate 8. On the
inner face of the support plate 8 there is mounted a
solenoid 15 whose armature 16 is urged to extended
position by a compression spring 17. The free end of
the armature 16 is coupled, by a vertically pivotable
joint 18 to a rod 19 engaged on the latching bar 12. In
its rest condition, the latching bar 12 is seated by
its ends in the foot zone or limb lOa of the guide
aperture 10 and in the corresponding foot zone or limb
of the guide aperture 11, to which position it i5 urged
by the compression spring 17 and the tension spring 13.
In this position, the end 12a of the latclling bar 1.~
siSuated inside the 1Ock l~ody 1 closely overlies the
levers 5 and prevents -theln from rising, thus securing
the lock mechanism agai.nst being ol~erated by the key
~5 6.
i230748
-- 10 --
When the solenoid 15 is energised, the armature 16
is moved inwardly, against the pressure of spring 1~,
and the latching bar l~ is drawn along the foot limb
lOa of the aperture lO and ll until it is positioned at
05 the base of the upright limb lOb and the corresponding
portion of aperture 11. In this position, the latching
bar l2 can rise, against the small tension of the
spring 13, when the key 6 is rotated to lift the levers
5. Thus, so long as the solenoid 15 is energised, the
lock can be operated by its key in the usual way.
The bolt 3 may have a greater height, as shown at
3a in Fig. l, and may be cut away, as at 3b, so as not
to foul the latching bar 12 when the bolt is in the
outward locking (i.e. protruding) position illustrated.
When the bolt has been moved inwards to the unlocking
(i.e. withdrawn) position, the upper surface 3c of the
bolt then rides under the latching bar 12 to ~)revent it
from passing downwardly in limb lOb and then forwardly
into limb lOa, i.e. to prevent inadvertent latching of
the levers 5 when the lock is in the unlocked state.
~ n the inner ~ace oX tht! sllpport plato 8 there is
mounted a micro-sw1tcll 20 having itS actuator 21
aligned with the protruding end 7a of the key shaf-t 7.
When the key shaft 7 i, engaged fully into the lock
body 1, Xor normal operation of the lock, the end 7a
has moved tlle actuator 21 to close the micro-switch
~() .
~23Q748
. 11 --
A stud 22 mounted on the support plate 8 carries a
micro-switch 23 having its actuator 24 positioned for
engagement by the latching bar 12 when the latter has
been raised up the upright zones or limbs of the
05 apertures 10 and 11 by the lifting of the levers 5. The
micro-switch 23 is normally closed-circuit, and is in
circuit with the current feed to the solenoid 15. When
the actuator 24 is moved upwardly by the latching bar
12, the micro-switch is made open-circuit and the feed
of current to the solenoid is cut off. The actuator 24
is spring-urged (not shown) towards its closed-circuit
condition.
The micro-switch 20 is arranged in an electronic
time-delay circuit having a delay period which is
variable from, say, 3 minutes to 1 hour. Engagement of
the key fully into position in the lock body 1 causes
actuation of the micro-switch 20 and the delay period
commences. During this delay period, the key cannot be
rotated to open the lock, because the latching bar 12
is in the foot limbs of the apertures 10 and 11 and
thus prevents the key levers 5 ~rom rising. At the end
o~ the predetermined delay period, the l;lme- delay
circuit switches n current feed to the xolenoid 15,
causing the latching bar 12 to be drawn along the foot
limbs of the apertures 10 and 11. The latching bar 12
is then free to ride up the upright position of the
~3~7~3
apertures 10 and 11, and accordingly -the levers 5 can
rise, when the key is turned, to permi-t movement of the
bolt 3. ~s soon as the levers 5 have risen
su~-ficiently, the latching bar 12 strikes the actuator
05 24 of the micro-switch 23, and current feed to -the
solerloid is cut off, -thereby saving wastage of current.
~s soon as -the key levers 5 have returned to their
lower position, the latching bar 1~ has also travelled
downwardly, under the action of -tension spring 13, and
is then projected along into the foo-t lirnbs of aperture
10 and 11 by the thrust of the compression spring 17.
The time-delay circuit also provides a
predetermined "open" period, which might be varied
from, say, 30 seconds upwards, o~ tne current feed to
the solenoid 15. If the key has not been rotated,
during the "open" period perrnitted, the solenoid ceases
to be energised and the latching bar 12 travels back to
the retaining position ln the manner described above.
Lf the key 6 is xemoved and re-inserted, during
the "open" period permitted, the actuation again o~ the
micro-switch 2~ commences a new delay period during
which the lock cannot be operated.
~ s the key levers 5 are held against rising, by
the latching bar 12, at all times when the solenoid 15
is not en~xgised, there is no possibility of the lock
being picked, except during an "open" period. This
- 13 _ ~3~748
period can be made very short, ~nd in any event the key
must be in position for it to occur.
The lock cannot be forced open by forced rotation
of the key, because the key levers 5 are secured
05 against upward movement by the latching bar 12 seated
in the foot limbs of the apertures 10 and 11.
If the key is rotated so forcefully as to break
it, the lock can be operated normally after removal of
the broken key and insertion of another replacement
key.
Additional optional features which may
advantageously be included are:-
(i) a buzzer or LED warning of "open" period
and/or run-down of batteries providing the
current feeds.
(ii) provision of a constant re-charging of
current-supply batteries, from the main
supply.
(iii) operation directly by a mains-fed current-feed
system.
(iv) the time-deLay ci.rcllltry ma~y be additi.orlalLy
arranged on a ~-hour clock basis to provide
one or more pre-set user times.
(v) the time delay circuitry may be arranged on a
~4-hour basis to prevent operation during a
selected night-time period.
~3074~3
- 14 -
(vi) An L.C.D. clock may be provided, to include
operation of item (v) above.
Referring now to Figs. 4 to 7, there is shown a
second embodiment which has minor variations of some of
05 the items shown in Figs. 1 to 3. In the lock of Fig. 1
there is a spring l~ which has the function of urging
the latching bar downwardly. In the lock of Yig. 4,
the tension spring 13 is replaced by a torsion spring
13a which is mounted on a pillar ]3b and has one end
secured in a transverse slot of the pillar, and the
other free end 13c positioned to bear down on the
latching bar 12.
In the lock of Fig. 1 there is a micro-switch 23
having its actuator 24 positioned to be engaged by the
latching bar 12 when the latter has been raised up the
upright zone of the apertures 10 and 11. In the lock
of Fig. 4, that arrangement is replaced by a
micro-switch having its actuator 24a abutted by a
resilient arm 25 carrying a roller 26 which is
contacted and moved by the latching bar 12 as it rises
Up the vertical zone lOb of the sLot l~.
In the loc,k ol` ~'ig. 1 therl? is a micro-switch 20
having its actuator ~1 aligned with the protruding end
7a of the key shaft 7, thereby to cause the
~5 micro-switch to close when the key is fully inserted.
In the lock of Fig. 4, the micro-switch 20 and the
i230748
- 15 -
actuator 21 are replaced by a micro-switch 20a having
its actuator 21b entering a lateral slot 27 in a
housing 28 in which is arranged a plunger 29 loaded by
a compression spring 30 to move in the direction of the
05 arrow. The housing 28 receives the protruding end 7a
of the key shaft and as the key is pushed fully home
in the direct~on of the arrow the plunger 29 is moved
to shift the micro-switch actuator 21a.
Fig. ~ shows a diagram for the electrical circuit
as so far described.
Fig~ 9 shows a diagram for a modified circuit
which allows for the introduction of selectable longer
periods of time into the delay which is obtainable
between insertion of the key into the lock and the
latching mechanism becoming actuated to move from
latching position to unlatching position.
Fig. 10 shows the functional diagram corresponding
to Fig. 9. Referring firstly to the upper part of Fig.
10 there is seen a timing interlock 30 which determines
a first (shorter) period oi time say 0-60 minutes.
Output from interlock 30 passes through a gatlng
circuit 31 to a circuLt 32 for contro]ling the
operation of the solenoid 1~. When only the delay
appertaining to interlock 30 is to be used the control
Iine 33 of gating circuit ~1 is earttled tllrough the N
(normal) corltacts of ganged switches 34. When it is
~23~)~48
desired to insert, say, one, two, three or four
additive periods of 24 hours each to the "normal"
delay, the ganged switches 3~ are set appropriately to
position 1,2,3 or 4, thereby bringing into circuit the
05 various outputs of a counter 35. The counter 35
essentially counts output signals from a clock circuit
36 (i.e. "real time") and an output is delivered from
the counter, according to the switch position selected
for switch 34, after the appropriate period of 24 hours
or a multiple thereof, thereby releasing the gating
circuit 31, such that the solenoicl 15 only becomes
actuated after the total additive time period of the
counter circuit and the timing interlock. The current
real time, i.e. time of day when setting, is set up by
operation of the clock circuit 36.
The device can be fitted to many lever safe locks
currently on the market, with a minimum of modification
to the lock.
Referring to Figs. 11 and 12 there are shown minor
variations in the structure of Figures ~-7, the
correspondin~ parts beillg irldicated by the s~lme
reference numerals but Wi th tlle addition of 100. The
L-shaped slot 10 of the lock of Fig. 1 is replaced by a
modiEied slot ltl having lL chamered portion to permit
~5 the bar 11~ to tilt when its other end rides up the
vertical limb of L-shaped slot 11~. The rod 119 is
~L~30748
- 17 -
connected to the arma-ture of solenoid 115 by the spring
117 and the torslon spring 113 extends coaxially
therewith.
It will be appreciated that the invention is not
05 restricted to the particular details described above
with reference to the drawings and that numerous
modifications and variations can be made without
departing from the scope of the invention as defined in
the following claims. For exarnple, optical switches
can be used operated by flags movable with the relevant
component instead of the micro-switches shown.
Further, an alarm can be provided to indicate when the
latching member is in its unlatching position. The
control circuit, including the timer can be located at
a position remote from the lock and/or a back-up
battery supply provided.
