Note: Descriptions are shown in the official language in which they were submitted.
1299217
"STRIKE ASSEMBLY"
This invention relates generally to security locks
and is concerned in particular with the strike
components of such locks.
It is known to provide a security lock strike
S assembly having a rotatably mounted keeper and an
electrical latch device engagable with the keeper to
hold it in a bolt retention position~ On deactivation
of the latch device the keeper is rotatable against a
coil spring so that the doorway may be opened by simply
10 pushing on the door. In one arrangement, disclosed in
Australian Patent 426,174, the latch device comprises an
elongate metal arm housed in the wall cavity and held in
its keeper locking position by an energized solenoid.
In another known commercial construction, the latch
15 device is rendered more compact by forming it as a
pivotable catch held in locking engagement with a stop
on the keeper by means of a solenoid-responsive finger
housed under the keeper and latch.
It will be appreciated that security strike
20 assemblies of the kind discussed can be readily
released, by withdrawal of electrical power, in the
q~
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event of a fire or other emergency and yet be otherwise
positively locked against unauthorized passage in either
direction through the door.
A limitation on the application of prior
5 arrangements is the throw of the lock bolt. The
rotatable keeper must always be configured so that the
assembly of keeper and bolt, which is typically of
rectangular section, does not seize as the keeper
rotates. To prevent seizure occurring, the keeper must
10 be shaped to accomrnodate the bolt as it turns but this
shaping tends to reduce the engagement interface between
the two and thus the degree of security. It is
therefore an object of the invention to provide a strike
assembly of the type having a rotatably mounted keeper
15 which is adaptable to long-throw bolts such as those
employed in prisons and like institutions.
It is a secondary object of the invention to -
provide an improved positive locking between the keeper
and its associated latch means.
It is a still further secondary object of the
invention to provide a strike assembly in which access
is allowable by the application of electrical power, so
' that one is not reliant upon the maintenance of such
power to prevent entry through the doorway in which the
25 assembly is mounted. A security arrangement fulfilling
this object is normally considered essential for an
assembly to be used in prisons and like institutions.
In one aspect, the invention accordingly provides a
strike assembly comprising:
a housing adapted for mounting in a door jamb;
129~
an exposed keeper formed by plural keeper elements
having opposed recesses which co-operate in a bolt
retention condition of the keeper to define a cavity for
a lockbolt, which keeper elements are mounted in the
5housing for rotational movement, on respective axes
parallel to the direction of movement o~ the bolt in and
out of said cavity, between said bolt retention
condition and d bolt release condition; and
releasable latch means supported in said housing
lOhaving an operative condition in which it engages the
keeper elements and so prevents said rotational movement
from the bolt retention condition.
There may further include means to place the latch
means in said operative condition, for example means
15such as one or more springs biasing the locking element
tv its operative condition.
The keeper elements preferably include bolt
restraint faces which abut edge to edge in said bolt
retention condition and are located on the side towards
20which the keeper elements move when executing said
rotaticnal movement. Wall portions opposite said bolt
restraint faces are then dimensioned so as to be spaced
apart in the bolt retention condition whereby they do
not come into contact when the keeper elements execute
25said rotational movement. To prevent geometric locking
of the lockbolt in the keeper as it rotates while
maintaining a firm engagement at the bolt retention
condition, each keeper element is formed with a convex
intsrnal face on each of these wall portions.
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The keeper elements are typically configured to
co-operatively define a cavity for a rectangular
lockbolt.
The latch means may include a single locking bar
5which is movable in a direction parallel to said axes to
engage registrable slots on both keeper elements and on
respective shafts or posts on which the keeper elements
are respectively rotatably mounted.
Alternatively, the latch means may comprise
l0re5pective locking elements slidable transversely with
respect to said axes, in a slot provided in structure
within said housing, to engage respective side grooves
in the keeper elements.
Each locking element is then preferably associated
lSwith a releasable catch to maintain it in said operative
condition, and wherein said groove in the keeper
element has inclined sides whereby, on release of the
catch, torsional spring means biases the keeper element
to force the lockin~ element out of the groove and to
20thereby rotate to said bolt release condition.
The assembly may further include step means to
define the bolt release condition of each keeper element
' and thereby prevent excessive rotation of the keeper
element, the keeper element rotating through less than
2590 between its bolt retention and bolt release
conditions.
In a second aspect, the invention further provides
a strike assembly comprising;
a housing adapted for mounting in a door jamb;
lZS~Zl7
an exposed keeper element mounted in the ~ousing
for rotational movement between a bolt retention
condition and a bolt release condition;
latch means supported in said housing including a
5 locking element movable to and from an operative
condition in which it engages respective abutments on
the keeper element and on structure fixed with respect
to the housing, whereby to prevent said rotational
movement of the keeper element from its bolt retention
ondition; and
means to place the latch means in said operative
condition.
The latch means may be advantageously released from
said operative condition by electrically actuable means
comprising e.g. one or more solenoids arranged for
activation to release the latch means so that it may
move from said operative condition against the biasing
means.
Such electrically actuable means may be associated
20with means which is responsive to correct location of
the lock bolt in the keeper to de-activate the
electrically actuable means and so allow return of the
latch means to said operative condition, but which
otherwise prevents de-activation of the electrically
25actuable means.
The second aspect of the invention may be
conveniently applied to the first in an arrangement in
which said locking element is a single element engagable
with abutments on the respective keeper elements. The
30locking element may be a single locking bar which is
movable in a direction parallel to said axes to engage
lZ5~
registrable slots on both keeper elements and on
respective shafts or posts on which the keeper elements
are respectively rotatably mounted.
The invention will be further described, by way of
5 example only, with reference to the accompanying
drawings, in which:
Figure 1 is a front isometric view of a first
embodiment of a strike assembly in accordance with the
invention, shown with its keeper in the bolt retention
10 condition;
Figure 2 is a view similar to Figure 1 but
showing the keeper in the bolt release condition;
Figure 3 is an exploded isometric view from
the rear of the assembly as seen in Figure l;
Figure 4 is a half section, on a plane
containing the axes of the keeper elements, of a second
embodiment of strike assembly in accordance with the
invention, having a similar keeper assembly to the first
embodiment but a different latch means;
Figure 5 is a cross-section on the line 5-5 in
Figure 4;
Figure 6 is an exploded isometric view of the
'principal operative components of the assembly half-seen
in Figures 4 and 5; and
Figure 7 an exploded view of an optional
additional feature for the second embodiment of Figures
4 to 6.
The strike assembly 10 illustrated in Figures 1 to
3 includes an elongate metal housing 12 with an integral
30 front facing plate 13, a rear cover 14 for the housing,
a keeper assembly 16 formed by a pair of rotatably
~g217
mounted exposed keeper elements 16a, 16b in register
with a front lockbolt receiving opening 18 in facing
plate 13, and latch means indicat~d generally at 20.
Housing 12 is intended to be mounted in a suitably
5formed recess in the jamb of a doorway and held in place
by means of screws fitted through apertures 22 in facing
plate 13. Bolt receiving opening 18 essentially
comprises a rectangular cut-out from a vertical side
edge of plate 13, which edge is at the side of the
l0doorway to which ~he doorleaf is intended to open. At
this same side, the outside of the assembly, the main
body of housing 12 is open between a pair of parallel
laterally protruding ledges 26a, 26b which, as will be
seen in due course, define limit stops for the
15rotational motion of the keeper elements.
At the other side, the housing is closed by a side
wall 28 which is offset inwardly to define a land 29
co-planar with and extending rearwardly from the inside
upright edge of opening 18. Above and below ledges 26a,
2026b~ housing 12 defines opposed U-section compartments
30a, 30b in which, as will be seen, respective solenoid
components of latch means 20 are housed. The upper
compartment 30b is extended to form a closed box 32 for
electrical circuitry. Box 32 is accessible by way of a
25removable cover panel 34 on the inside of the box and
includes respective apertures 36a, 36b to admit
el~ctrical leads.
Cover 14 is detachably fastened to housing 12 by a
pair of screws 11 which extend through apertures 15a,
3015b in the housing adjacent compartments 30a, 30b and
through matching apertures in tabs 14a on the cover.
12g~217
The cover provides a rear upright ledge 26c which
registers with ledges 26a, 26b.
Projecting rearwardly from the reverse face of
facing plate 13 just above and below opening 18 are a
5 pair of posts 38a, 38b which provide hinge pins on which
the keeper elements 16a, 16b are respectively mounted
for rotational movement, on respective axes 17a, 17b
(Figure 3), between a bolt retention condition tFigures
1 and 3) and a bolt release condition (Figure 2). Each
lO post includes a slightly broader base portion 40 on
which the keeper elements are actually mounted, with an
interposed split bush 42, and a relatively narrower
outer portion 44 which includes a diametral slot 46
extending for most of its length from the tip of the
15 post. Slots 46 are a component of latch means 20.
Keeper elements 16a, 16b may comprise unitary metal
casings of substantial thickness. They are almost
identical and each consists essentially of a broad body
portion 48, which is rotatably received on the base
20 portion 40 of a respective post 38a or 38b, and an
assembly 50 of wall portions which define a channel
recess 52 closed at the rear of the keeper element. In
the bolt retention condition of the keeper the two
recesses 52 are opposed and in register and thereby
25 co-operate to define a cavity 53 for a long-throw
rectangular-section lockbolt. Axes 17a, 17b are
parallel to the direction of movement of the bolt in and
out of cavity 53. Wall portions 50 include outer bolt
restraint faces 54 that abut edge-to-edge in the bolt
30 retention condition, keying together (Figure 1) by
virtue of co-operative tongue and groove formations 56
at their interface. The keeper elements further include
inner wall portions 58 opposite restraint faces
~9~Z~7
54 which are separated and inwardly convex. The
separation prevents the keeper elements from contacting
as they rotate to the bolt release condition and the
convexity precludes geometric locking between the keeper
5 elements and the lockbolt. The bolt cavity 53 is
defined between wall portions 58 by land 29.
The bolt release condition of the keeper is
determined ~y contact of the keeper elements with ledges
26a, 26b (Figure 2). The bolt retention condition is
10 further strengthened by contact of curved shoulders 55
with the outer corners of opening 18 (Figure 1).
Keeper elements 16a, 16b are in fact biased to the
bolt release condition by a pair of torsion springs 60
mounted on bush 42 within a counter bore in the
15 respective elements. However, latch means 20 is
provided to maintain the bolt engagement position except
when the latch means is positively réleased by external
intervention. The key effective element of the latch
means 20 is an elongate, square-section locking bar 62
20 which extends between and seats in slots 46 in posts
38a, 38b and in registering diametral slots 66 in
respective bosses 64a, 64b integrally formed on the body
portions 48 of keeper elements 16a, 16b. When cover 14
is in place, locking bar 62 is biased to this operative
25 condition by a pair of helical compression springs 65
retained on posts 38a, 38b against the inside of cover
14.
The release mechanism for the latch means is
electrically operable and comprises a pair of solenoids
30 68a, 68b, already adverted to, housed within
- compartments 30a, 30b. Armatures 70 of these solenoids
~9~2:~7
engage respective straps or tabs 72 which are slidably
but rotationally carried by posts 38a, 38b as shown,
between locking bar 62 and the respective springs 65.
These tabs are fastened to bar 62 by means of central
5 screws at 74.
The arrangement of the solenoids is such that their
activation by electrical current drives armatures 70
rearwardly against tabs 62 and thereby lifts ~abs 72 and
moves bar 62 out of slots 66 (but still within slots
lO 46), against springs 65. Torsional springs 60 will bias
the keeper elements rotatably outwardly to release the
lockbolt.
An alternative embodiment of latch means 20' is
d~picted in Figures 4 and 5, in which like parts are
15 indicàted by like reference numerals. In this
embodiment, a separate solid locking element 62' is
associated with each keeper element 16a', 16b' and is
held in its operative condition by a respective
pivotable catch 80 triggered in turn by a solenoid 68a',
20 68b'.
Figures 4 and 5 show only one of these mirror image
arrangements. Keeper elements 16a' and 16b' include
respective solid pins 116, 117 with end bosses 64'
journalled in a front plate 114 behind cover 13' and in
25 an intermediate rear plate 118. Locking element 62' is
slidable inwardly and outwardly of a close-fitting
vertical slot 82 defined in a generally U-section holder
84 held by multiple pins 85.
Element 62' is of axial length equal to that of the
30 body of keeper elements 16a', 16b' and consists of a
flanged cage 63 and a hardened steel dowel 63b held
:129~Z17
between the flanges 63d of the cage 63 SO as to define a
curved forward edge of the locking element. Element 62'
is biased outwardly of slot 82 by a pair of light
helical compression springs 65' mounted in opposed blind
5 bores 86, 87 in element 62' and holder 84. Locking
element 62' engages into either of two longitudinal
indexing grooves 88, 89 in the back surface of keeper
element 16a'. Deeper groove 88 defines the bolt
retention position and shallower groove 89 the bolt
10 release position (broken lines in Figure 5). An
outstanding rib 91 on each keeper element 16a', 16b'
near groove 89 is arranged to abut an inclined
complementary end face 84a of holder 84 (as indicated by
broken lines in Figure 5) thereby determining the
15 maximum open position of the keeper elements.
Catch 80 is hinged at 90 in holder 84 behind slot
82 within a transverse slit 92 in the holder. The catch
has three arms. A forward arm 80a extends, with
horizontal and vertical clearance, into a notch 94 in
20 the rear of locking element 62' and has an orthogonal
seat 96 for the upper edge 95 of notch 94. A rearward
catch arm 80b is braced by a heavy helical compression
' spring 98 to rotatably bias catch 80 so that seat 96
normally positively engages edge 95. A long depending
25 forked arm 80c e~tends through a slot 81 in the end of
rear plate 118 and snugly locates between shoulders 101
and a pin 99 on an end adaptor 102 fitted to the
armature 70' of solenoid 68a', which is mounted to the
rear face of plate 118.
Activation of solenoid 68a' by application of
electrical power moves armature 70' to rotate catch 80
lZ~23.7
12
against spring 98, thus dissengaging seat 96 from notch
edge 95. The clearance in notch 94 is sufficient
vertically for this disengaging to occur and sufficient
horizontally for the locking element to move back as
5 torsion springs 60' rotate keeper element 16a'. The
forward vertical edge of element 62' is rounded and
grooves 88, 89 correspondingly cambered, and springs
60', 65' suitably balanced, so that springs 60' can
cause keeper element 16a' to lift locking element 62'
10 against springs 65'. The keeper element is rotated open
by springs 60' until rib 91 strikes face 84a of holder
84.
It will be appreciated that in this second
embodiment, the side walls of groove 88 and slot 82
15 constitute respective abutments engaged by locking
element 62' to prevent rotational movement of the keeper
element when seat 96 is engaging notch edge 95. It will
also be noted that the keeper element is of
cross-section slightly different from the first
20 embodiment in that wall portions 58' ~Figure 5) exhibit
a wholly rounded (180~) outer edge 58a.
When the solenoid is de-activated, and the door
closed, the re-entering lockbolt will push against edges
58a to dislodge element 62' from groove 89 and so return
~5 the keeper elements to the bolt retention position, in
which spring 98 ensures re-engagement of notch edge 95
in seat 96. Groove 89 is configured to facilitate such
action while preventing inadvertent automatic relocking
of the assembly without the bolt in the keeper.
30 Moreover, the angled location of the keeper elements at
less than 90~, as evident from Figure 5 (and also from
1'~992~7
Figure 2 for the first embodiment), also facilitates the
keeper closing action of the lockbolt. Furthex
excessive opening of the keeper elements is of course
prevented by abutment of rib 91 with face 84a of holder
5 84. Such a self-closing and locking facility is
valuable for institutional application of the invention,
as is the "fail secure" arrangement by which the door is
not dependent on electrical power to remain locked.
Figure 6 shows some additional subsidiary features
10 not shown in Figures 4 and 5. Microswitches 110
responsive to movement of the forked arms 80c of cat~hes
80 monitor releasing operation of solenoids 68a', 68b'.
A further microswitch 112 on the side of one of the
holders 82 is responsive to removal of the cover 114,
15 which abuts the outer surface of holder. Each
microswitch is wired to activate an alarm or other
warning device at a remote monitoring station.
The particular advantage of the illustrated forms
of strike assembly is the ability to apply the assembly
20 to locks with a long-throw rectangular bolt without risk
of seizure of the bolt in the keeper when the latter
rotates. The problem of latching a two-part keeper is
' met in a very neat and effective manner which is also
highly positive :in that it entails a coupling of
25 abutment surfaces on the keeper elements and on the
housing. A further feature of the particular latch
means is that it is normally engaged to lock the door
but is easily and simply released by application of
electrical current to a pair of solenoids.
Figure 7 depicts an optional additional feature for
the embodiment of Figures 4 to 6, viz a switch assembly
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14
for preventing locking of the keeper unless the lockbolt
is correctly located therein. A hollow body 120 is
secured by pins between plates 114, 118 in the space
between the short rounded-end wall portions 58' of
5keeper elements 16a', 16b', as shown by dot-dash lines
at 122 in Figure 5. A spring-loaded, hollow, s~gmental
switch lever 124 is pivoted at 126 in a recess 128 of
body 120 so to be rotatable from an outwardly projecting
position (that shown in Figure 7) to and a recessed
l0position in which it triggers a microswitch 129. On
entry of the bolt, the front edge strikes the curved
surface 125 of lever 124, rotating the lever inwardly
against a torsional spring 130 to trigger the switch.
Switch 129 is arranged in circuit so that the keeper
15elements cannot be locked ti.e. solenoid power
withdrawn) until the switch is activated by lever 124.
To prevent unauthorized locking of the door, lever
124 can be locked in its outward position by a beak
latch 132 which locates in the hollow inturned lever
20124. Latch 132 is held in this position by a third
solenoid 134 which is mounted with its axis horizontal
in the space between the two primary solenoids 68a',
68b'. ~he armature 135 of solenoid 134 abuts a lever
136 that unlies and bears against the bottom of latch
25132. Latch 132 and lever 136 are hinged at 133, 137
respectively. When solenoid 134 is not activated, lever
136 is not restrained and latch 132 is rotated by a
torsional spring 138 to release switch lever 124.
