Note: Descriptions are shown in the official language in which they were submitted.
34~)~
S~FE DOOR LATCH WITH DEFORMATION ACTUATED INTERLOCK
BACK~ROUND OF THE INVENTION
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Field of the Invention
The invention relates to safe enclosures which may be installed
at locations accessible to customers for vending merchandise,
dispensing money or receiving deposits. More particularly the
invention relates to sheet metal enclosures for machines which
are inskalled in lobbies of buildings and other areas where the
public has access to the machines and where a potential
lo attacker would have only a limited period of time to break into
the enclosure before the police or security personnel would be
able to arrive and intervene against the attacker.
Prior Art
Safe enclosures are well known in the prior art, ranging from
massive vaults to simple key lock tin boxes. Massive vaults
are provided to resist prolonged attack by professional safe
crackers and therefore are very thick and heavy. They are
unsuited for vending machines because of their mass, bulk and
cost. The simple sheet metal enclosures of the prior art, an
example of which is the trunk of an automobile, primarily
functions to Xeep amateur thieves from gaining access to the
contents. With an inwardiy directed force on a sheet metal
enclosure, using a punch or other sharp instrument, the sheet
metal will deform so that the entire lock mechanism ~ill pop
out of its opening to give access to the latch mechanism. With
the lock removed, it is often a simple matter to rotate the
latch mechanism with a screw driver or other tool and open the
sheet metal safe in a matter of seconds.
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It is known in the art to provide interengaging elements at
the periphery of a door to prevent the door or the side wall
from being deformed sufficiently to allow the latches to
disengage and the door to open. An example is shown in U.S.
Patent 3,819,228. It is also known to provide pins or other
engaging elements to prevent removal of a door by merely
removing the hinges as taught in U.S. Patent 3,970,340.
None of these prior art teachings are effective to protect a
sheet metal enclosure following destruction or removal of
the lock mechanism.
In U.S. Patent 146,782, auxiliary bolts having no connection
to the lock are provided to spring out and fasten the door
when a trigger plate over the lock is pressed. This teaching
adds significant cost to the enclosure and does not take
advantage of deformation of the materials from which the
enclosure itsel~ is made.
SUMMARY OF THE INVENTION
It is an advantageous effect of the invention to provide a
relatively light, yet secure, sheet metal fabricated safe
enclosure which is not so heavy and massive so as to be
inappropriate in a public lobby of a store or bank. It can
be fastened to the floor to prevent removal of the entire
machine and have thin inexpensive walls to reduce the space
requirements and floor load supporting requirements yet
provide significant resistance to attack. These and other
objects of the invention are provided by designing into the
latches and latch bolts, apertures or projections which
interlock with mating projections or aperture respectively
upon deformation of the sheet metal door or the sheet metal
walls of the enclosure sufficient to cause damage to the
lock or latches. Such interlocking prevents retraction of
the latches or latch bolts holding the door closed even if
the lock mechanism is completely destroyed or removed by
force.
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Brief nescriptiOn of the Drawings
.
Figure 1 shows an e~ample enclosure in which the invention has
been applied.
Figure 2 shows an inside view of a door having latches
according to the teachings~of this invention.
Figure 3 shows a top view of the door.
Figure 4 shows a cross section of a latch and lock mechanism in
accordance with the invention.
Figure 5 shows a cross section of a bolt type latch in
accordance with the invention.
Figure 6 shows an alternate interlock embodiment.
Figure 7 show a side view of the alternate embodiment.
Figure 8 shows still another embodiment of a latch interlock
according to the invention.
Description of the Preferred Embodiment of the Invention
Figure 1 shows a sheet metal automatic teller machine enclosure
incorporating the invention. The enclosure has a top 11, a
bottom 13, a rear wall, and two side walls 17 and 19. Hinges
are attached to the door jam at the vertical front edge of wall
17 in the usual manner for mounting an access door 27 to close
the front of the enclosure. Wall 19 has a catch assembly 15
shown in greater detail in the expanded inset view. Catch
assembly 15 includes a catch pin 21 mounted to angle plate 23
for engagement with a latch 41 mounted in the door which is
shown in Figure 2. In addition to catch pin 21, interlock pin
25 is provided which interlocks with a mating interlock
aperture 47 in latch 41 to capture the latch in the latched
position if the sheet metal enclosure is subjected to
deformation during an attack.
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It has been found that the latch is more advantageously made of
a hardened stock which is not easily welded. For this reason,
forming an aperture or other mating interlock surface in the
latch before hardening results in a stronger assembly.
s Access door 27 has a plura~lity of tabs 26 which engage slots 16
when the door is closed to make it difficult to pry the door 27
away from wall 19. Such tabs are well known in the art for
preventing a door from opening by deformation of a side wall
and cooperate with, but form no part of, the inventio~.
Referring now to Figure 2, the inside of the access door 27 is
shown. The outside of the door 27 is a simple planar surface
having a key lock for controlllng the latches to open the door.
The door 27 is made of sheet metal having a number of
reinforcing sheet metal strips 29 and 31.
Mounted at the left vertical edge of door 27 as shown in figure
2 is a hinge 33. Tabs 28 are formed as part of sheet metal
reinforcing strip 29, which is also shown in figures 3, 4, and
5. Tabs 28 extend behind the front edge of wall 17. Tabs 28
prevent removal of the door 27 by cutting the hinge 33 from
either the door or the wall.
In the center of the right edge of the door is a latch 41
operated by a lock mechanism 43. Latch 41 is shown in the
latched position where catch 45 engages catch pin 21 in the
sidewall of the enclosure. Latch 41 also has an aperture 47
which engages interlock pin 25 only upon deformation of the
wall or door of the enclosure. Lock 43 is adapted to rotate
latch 41 counterclockwise approximately 90 degrees to unlatch
door 27. When latch 41 is rotated '90 degrees, bolt 49 and
latch 51 are also moved by virtue of their being fastened to
latch 41 by pins 53 and 55 respectively. Bolt 49 passes
downward inside of the door through bracket 60 and through
guide plate 57 which holds bolt 49 against the inside of the
door. Bolt 49, supported by plate 57, catches behind the front
bottom edge of the door jam of the enclosure and holds the door
closed when the bolt has been e~tended with the door closed.
When the door is closed ,nd bolt 59 is fully extended, pin 61
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on bracket 60 is ju~taposed to aperture 62 in bolt 49. In the
event that an attack is made upon the lock area of the door,
the door will be deformed inward in the vicinity of the lock,
allowing the top of bolt 49 to move inward. Such motion will
s cause aperture 62 to engage pin 61 and thereafter prevent
retraction of bolt 49 even if lock 43 is ultimately destroyed
and latch 41 could otherwise be rotated. In like manner latch
51 has an aperture 59 which is engaged by the edge of the door
when the door is deformed as shown more clearly in Figure 3
Referring then to Figure 3, latch 51 is shown extending through
opening 64. Latch 51 has an aperture 59 which is engagable by
interlock projection 63 which is part oE the top edge of the
door. If pressure is placed by means of a hammer or otherwise
on the outside upper surface of the door, web 65 having
projection 63 is deformed toward latch 51 by virtue of it being
supported by member 66 ~astened to the top of the enclosure as
shown in figure 1. When web 65 is deformed, projection 63
engages aperture 59 in latch 51 to prevent latch 51 from
rotating out of opening 64 so as to release the top of the door
from its latched position.
Figure 3 also more clearly shows reinforcing sheet metal strip
29 to which hinge 33 is fastened. Tabs 28 extend behind hinge
33 when door 27 is closed to prevent access by removing hinge
33.
Figure 4 shows a section through the door at the lock and more
clearly show the operation and configuration of latch 41 and
its relationship to interlock pin 5. From Figure 4 it can be
more clearly seen that when a hammer or other tool is used to
attempt to open or destroy lock 43, the front face of the door
in the vicinity of lock 43 will deform inward permitting latch
41 to interlock with pin 47 and thereafter prevent rotation of
latch 41 even if lock 43 is ultimately destroyed.
Referring now to Figure 5, the door near the bottom as shown by
section lines 5 - 5 in Figure 2 is presented in cross section.
Figure 5 clearly shows bolt 49 having an aperture 62 which is
captured on pin 61 when either the front of the door is pushed
inward or alternately when the portion of the door in the lock
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area is pushed inw~rd causing bolt 49 to assume an angle from
the bottom of the door upward. Since pin 61 is mounted some
distance from the bottom of the door, bolt 49 will move inward
and be captured on pin 61. Backing support 66 may be some
heavy component such as a transformer or a frame member which
- resists inward motion of bracket 60 if force is applied to the
outside of door 27. Abnormally high force as may occur when
someone is attempting to force open door 27 will cause bracket
60 to deform toward latch 49.
Figure 5 also shows the tabs 26 in,the door at the right, and
another, 28 shown at the hinge. These engaging tabs ~are well
known in the prior art and are useful to provide improved
attack resistance to the sheet metal enclosure but form no part
of applicants invention.
Referring now to Figure 6, an alternate embo~iment for the
latch bo]t 57 is shown as a bolt 67 having a projection 69. The
interlock supporting bracket 71 is provided with apertures 73
and 75 to engage the mating surface 69 and prevent the door
bolt from being retracted if the door is deformed from the
front or the entire door is pushed inward. Figure 7 shows the
same bolt 67 and bracket 71 in vertical position. As can be
better seen in figure 7, if force is applied to the door 27
from the outside, bracket 71 will deform and interlock latch
bolt 67 to prevent retraction. Figure 8 shows an alternate
embodiment of bolt 67 wherein the bolt carries the aperture and
the interlock support carries the projections.
It will be recognized by those skilled in the art of enclosure
design that other deformable materials such as plastics ma~ be
substituted for sheet metal to achieve to advantages of the
invention These and other variations in the implementation of
the invention will suggest themselves to those skilled in the
art without departing from the spirit and scope of the
invention as measured by the following claims.
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