[0001] The present invention relates to a bolt for locks, particularly for panic-safe locks
for double doors.
[0002] In double doors, used as emergency doors, both doors open outward, and the door normally
used to enter and to exit (hereinafter termed door A) is provided with a panicsafe
lock having a spring latch and a bolt and designed so that the spring latch and the
bolt can be moved simultaneously into their release position by operating the handle.
The other door (hereinafter termed door B) acts as lock stile for door A and has an
upper catch and a lower catch which are connected by means of rods to a so-called
panic-safe strike lock actuatable by means of a handle of its own.
[0003] The particularity of emergency doors of this kind is that the spring latch and the
bolt of the lock installed on door A engage selvages of the strike lock of door B,
the mechanism of which is set so that if only the lock of door A is operated to open
it, i.e. if the latch and the bolt are retracted, it is possible to open only door
A, since the strike lock keeps its catches in locking position.
[0004] On the other hand, in the strike lock of door B there is a pusher which, when the
strike lock is actuated, is expelled by said strike lock and acts on a sort of pushbutton
that releases the mechanism of the lock of door A, causing the retraction of the latch
and of the bolt. Therefore, if the strike lock is actuated, door B opens and door
A opens as well.
[0005] In known locks there is the drawback that the release pushbutton can be accessed
from the outside, so that it is relatively easy to open it, with a suitable tool,
in order to unlawfully open the strike lock.
[0006] The technical aim of the present invention is to provide a bolt including a release
mechanism that is designed so that it can be activated only when the bolt is inserted
in the respective selvage of the strike lock, so as to ensure maximum security against
break-in attempts.
[0007] With the above aim in view, the invention provides a bolt for a lock, particularly
of the panic-safe type, which is installed in one door of a double door and is operatively
associated with a strike lock installed in the other door, characterized in that it
comprises a flat sliding plate accommodated in a seat of the bolt and guided, against
the biasing action of elastic transmission means, at right angles to the sliding direction
of said bolt, said sliding plate having a lug for abutment against a fixed element
of the lock when the bolt is engaged in the strike lock, a slider being furthermore
provided which is guided in said bolt parallel to the sliding direction of said bolt
and has a tang protruding frontally from the bolt, said slider cooperating with said
sliding plate so that when the bolt is engaged within the strike lock, the release
action produced on the tang by means of the strike lock causes the slider to move
the sliding plate into a position in which said lug does not abut against said fixed
element, allowing retraction of the bolt into the lock due to the release action.
[0008] Further particularities of the present invention will become apparent from the following
description of a preferred embodiment, illustrated only by way of nonlimitative example
in the accompanying drawings, wherein:
figure 1 is a side view of the bolt;
figure 2 is a top view;
figure 3 is a sectional view, taken along the plane III-III of figure 1;
figure 4 is a sectional view, taken along the plane IV-IV of figure 1;
figure 5 is a side view of the sliding plate and of the slider.
[0009] With reference to the above figures, the reference numeral 1 designates the faceplate
of the casing of a panic-safe lock, in which there is a rectangular opening 2 through
which the bolt 3 protrudes outside.
[0010] The bolt 3 is guided not only in the opening 2 but also in the sliding direction
A by a plate 4 the opposite ends whereof are fixed in the rear plate 5 and in the
covering plate 6, which close the sides of the casing.
[0011] The plate 4 slidingly engages a notch 7 which is open on the rear edge 8 of the bolt
3 and extends toward the front edge 9 along the direction A. A laminar seat 10 is
formed in the bolt 3 on the plane thereof and is open toward the rear edge 8. The
seat 10 is furthermore open upward, where it forms an opening 11, and downward, where
it forms a shoulder 12 and a recess 13. Below the shoulder 12 there is a tooth 14
protruding downward and suitable to cooperate with the tumbler of the bolt actuation
cylinder 25 which is described hereinafter.
[0012] An extension 15 rises from the upper edge of the bolt, and a seat 16 is formed therein
for a spring 17 the upper end of which is retained against a short pin 18 driven through
a hole 19 of the extension.
[0013] The spring 17 acts by compression on a flat sliding plate 20 accommodated in the
seat 10.
[0014] The sliding plate 20 is substantially rectangular and is guided in the seat 10 in
the direction B at right angles to the direction A by the engagement of pins 21, 22
driven through the bolt in slots 23, 24 of the sliding plate which are elongated in
the direction B. The spring 17 keeps the sliding plate 20 pressed downward so that
it rests on the plate 4, where the lower edge of the sliding plate can be accessed
through the recess 13 for the engagement of the tumbler of a cylinder lock 25, by
means of which the bolt can be operated manually with a key.
[0015] The opposite ends of the pin 22 engage slots of the rear plate 5 and of the covering
plate 6 which are elongated in the direction A and set the stroke of the bolt.
[0016] As more clearly shown in figure 5, the sliding plate 20 is affected, in its central
region, by a rectangular slot 26 having two sides 27, 28 that are parallel to A and
an end side 29 which is parallel to B.
[0017] A lug 30 extends from the upper side 27 of the slot 26 toward the lower side 28 and
has an inclined edge 31 toward the front edge 9 of the bolt and a step 32 toward the
rear edge 8. The distance between the crest of the lug 30 and the lower side 28 of
the slot 26 is greater than the thickness of the plate 4. The inclined edge 31 forms,
together with the upper side 27, a step 33 the distance of which from the end side
29 is slightly greater than the width of the plate 4. When the bolt 3 is fully retracted
into the lock and the sliding plate 20 rests on the plate 4, said plate is recessed
between the side 29 and the tooth 33 and locks the sliding of the bolt, since the
sliding plate is axially retained by the pins 21, 22. However, if the cylinder 25
is actuated, the tumbler of said cylinder engages the recess 13, lifting the sliding
plate 20 and allowing the plate 4 to slide along the notch 7.
[0018] An additional seat 34 is formed in the bolt 3 laterally to the seat 10; a slider
35, substantially constituted by a rectangular plate, is guided in the direction A
in said seat 34. The slider 35 has, toward the rear edge of the bolt, a pin 36 protruding
laterally and engaging a slot 37 of the bolt which is elongated in the direction A.
A cylindrical tang 38 is rigidly coupled to the slider 35 on the side directed toward
the front edge of the bolt 3, is guided in a hole 39 of said bolt and has a hemispherical
end. The hole 39 is open on the front edge of the bolt, and the tang 38 has such a
length that in practice only the hemispherical end can protrude from the front edge
of the bolt.
[0019] A polygonal slot 40 is formed in the slider 35 and forms an inclined plane 41 with
one of its sides. A pin 42 is engaged in the slot 40, protrudes from one side of the
sliding plate 20 and is operatively associated with the inclined plane 41.
[0020] The operation of the described device is as follows. When the bolt 3 is inserted
in locking position in the appropriately provided selvage of the strike lock, the
tooth 14 is proximate to the faceplate 1. In this position, the lug 30 is to the left
of the plate 4, which thus engages the step 32.
[0021] In this situation, if the strike lock is operated, the appropriate element provided
to release the lock, for example a pusher controlled by the actuation of a handle,
acts on the tang 38, making the slider 35 slide in the direction A from the front
edge 9 toward the rear one 8.
[0022] In this manner, the inclined plane 41 acts on the pin 42, forcing the sliding plate
20 to rise until the step 32 passes beyond the plate 4 and thus allowing the pusher
to push the entire bolt inside the lock.
[0023] When the plate 4 has passed beyond the lug 30, the action of the spring 17 makes
the sliding plate 20 engage the plate 4, which is retained between the end side 29
and the step 33 of the lug.
[0024] In order to restore the door closure condition, one operates the cylinder 25, which
lifts the sliding plate 20 and then, as soon as said sliding plate has disengaged
from the step 33, pushes the bolt out into its locking position.
[0025] A substantial prerogative of the present invention is constituted by the fact that
when the bolt is inserted in the strike lock, the tang 38 cannot be accessed from
the outside, so that it is not possible to retract the bolt into the lock with unauthorized
actions which instead a tang that can be accessed through the adjacent rabbets of
the doors would facilitate.
[0026] Where technical features mentioned in any claim are followed by reference signs,
those reference signs have been included for the sole purpose of increasing the intelligibility
of the claims and accordingly such reference signs do not have any limiting effect
on the scope of each element identified by way of example by such reference signs.
1. Bolt for a lock, particularly of the panic-safe type, which is installed in one door
of a double door and is operatively associated with a strike lock installed in the
other door, characterized in that it comprises a flat sliding plate (20) accommodated
in a seat (10) of the bolt and guided, against the biasing action of elastic transmission
means (17), at right angles to the sliding direction of said bolt, said sliding plate
having a lug (30) suitable to abut against a fixed element (4) of the lock when the
bolt is engaged in the strike lock, a slider (35) being furthermore provided which
is guided in said bolt parallel to the sliding direction of said bolt and has a tang
(38) protruding frontally from the bolt, said slider (35) cooperating with said sliding
plate (20) so that when the bolt is engaged within the strike lock, the release action
produced on the tang (38) by means of the strike lock causes the slider (35) to move
the sliding plate (20) into a position in which said lug (30) does not abut against
said fixed element (4), allowing retraction of the bolt (3) into the lock due to the
release action.
2. Bolt according to claim 1, characterized in that said sliding plate (20) has a slot
(26) which is open on the rear edge of the bolt (3) and has an upper side (27) from
which a lug (30) protrudes, said lug forming two opposite steps (32, 33) suitable
to abut against a plate (4) which is fixed in the lock and is guided through a notch
(7) of the bolt which is parallel to the sliding direction thereof, said bolt (3)
having a seat (16) for accommodating a spring (17) which acts on said sliding plate
(20) so as to make it rest with said upper side (27) on said plate (4) in the position
in which it abuts against said steps (32, 33) and retains the bolt.
3. Bolt according to claim 2, characterized in that said slider (35) has a slot (40)
forming an inclined edge (41) and engaged by a pin (42) protruding laterally from
said sliding plate (30), said inclined edge (41) being suitable to act on said pin
(42) when said tang (38) is pushed into the bolt (3) so as to lift the sliding plate
(20) into a position in which said lug (30) disengages from said plate (4) to allow
the retraction of the bolt into the lock, said spring (17) being suitable to lower
the sliding plate (20) into the position for engagement on said plate (4) and for
retention of the bolt after the lug (30) has passed beyond said plate (4).
4. Bolt according to one of the preceding claims, characterized in that said slider is
constituted by a plate (35) which is guided in a seat (34) that lies laterally to
the seat (10) for the accommodation of the sliding plate (20), and in that said tang
(38) has a hemispherical end protruding from the front edge of the bolt.