EP0242596B1

EP0242596B1 - Safe door latch with deformation actuated interlock

Info

Publication number: EP0242596B1
Application number: EP19870104074
Authority: EP
Inventors: Pamela K. Jones
Original assignee: International Business Machines Corp
Current assignee: InterBold
Priority date: 1986-04-24
Filing date: 1987-03-20
Publication date: 1990-09-19
Also published as: EP0242596A3; DE3764996D1; JPH0730640B2; JPS62258070A; EP0242596A2

Description

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 which upon attack by an unauthorized force impose one or more additional impediments to an attacker who has only a limited period of time to break into the enclosure before the police or security personnel are able to arrive and intervene against the attacker.
Especially the invention relates to an enclosure as disclosed in US-A 4 266 488, upon which the preamble of claim 1 is based.
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 keep amateur thieves from gaining access to the contents. With an inwardly force on a sheet metal enclosure, using a punch or other sharp instrument, the sheet metal will deform so that the entire lock mechanism will 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.
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 US 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 US 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.
The problem was recognized by the patentee of US Patent 146,782 way back in 1873 but the solution using deformation to interlock the latches preventing retraction has not until now been invented. 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 itself is made.
From US Patent 4 266 488 a relocking mechanism for a safe is known which comprises one or more relocking devices mounted on a panel of the enclosure rearwardly of the main bolt and operable to prevent retraction of the bolt. Each relocking device includes a mounting plate carrying a pair of uni-directional hinges constituted by roller clutches, a plate-like bolt-engaging member that is connected to the hinges for uni-directional pivotal movement from a disengaging position to a bolt-engaging position. The bolt-engaging member is resiliently biassed towards the bolt-engaging position but is normally retained in the disengaging position by a control element which releases the member only in the event of forcible attach on the enclosure. The control element which releases the member is a strip spanned on the inside of the enclosure and when broken by forces of an attack relocks the bolt and prevents in its retraction.
The construction of this mechanism is rather complicated, mal-functions by inadvertent breaking or actuating of the strap or cable respectively controlling the interlock mechanism, cannot be excluded. Furthermore the mechanical design follows different aspects as the one used in the present invention.
Starting from this point it Is an object of the invention to provide an enclosure with an interlock system which guarantees a high security without using complicated mechanical system.
This object is achieved by an enclosure according to claim 1. Further embodiments of the enclosure are given in dependent claims 2 to 9.

Fig.1 shows an example enclosure in which the invention has been applied;
Fig.2 shows an inside view of a door having latches according to the teachings of this invention;
Fig.3 shows a top view of the door;
Fig.4 shows a cross section of a latch and lock mechanism in accordance with the invention,
Fig.5 shows a cross section of a bolt type latch in accordance with the invention;
Fig.6 shows an alternate interlock embodiment;
Fig.7 shows a side view of the alternate embodiment; and
Fig.8 shows still another embodiment of a latch interlock according to the invention.

Descriotion of the Preferred Embodiment of the Invention

Fig.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 Fig.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.
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.
Access door 27 has a plurality 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 invention.
Referring now to Fig.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 controlling 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 Fig.2 is a hinge 33. Tabs 28 are formed as part of sheet metal reinforcing strip 29, which is also shown in Figs.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 extended with the door closed. When the door is closed and bolt 49 is fully extended, pin 61 on bracket 60 is juxtaposed 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 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 Fig.3 .
Referring then to Fig.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 of 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 67 fastened to the top of the enclosure as shown in Fig.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.
Fig.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.
Fig.4 shows a section through the door at the lock and more clearly shows the operation and configuration of latch 41 and its relationship to interlock pin 25. From Fig.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 with aperture 47 to interlock with pin 25 and thereafter prevent rotation of latch 41 even if lock 43 is ultimately destroyed.
Referring now to Fig.5, the door near the bottom as shown by section lines 5 - 5 in Fig.2 is presented in cross section. Fig.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 area is pushed inward 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.
Fig.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 Fig.6, an alternate embodiment for the latch bolt 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. Fig.7 shows the same bolt 67 and bracket 71 in vertical position. As can be better seen in Fig.7, if force is applied to the door 27 from the outside, bracket 71 will deform and interlock latch bolt 67 to prevent retraction. Fig.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 may be substituted for sheet metal to achieve the 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 scope of the invention as measured by the following claims.

Claims

1. An enclosure comprising

sheet metal walls (11,13,17,19) and a lockable sheet metal access door (27),

said door having a latch (41, 51, 49) which engages one of said walls to prevent opening said door,

and said latch being retractable by a lock mechanism (43) for opening said door,

an interlock (25, 63, 61) coupled to said sheet metal and a mating interlock (47, 59, 62) being part of said latch,

said mating interlock being engaged by said interlock to prevent retraction of said latch when said sheet metal is deformed, characterized in that

said interlock (25, 63, 61) being fastened to said sheet metal (19, 27, 27) in a fixed and stable position, whereby in the event of a deformation of the sheet metal said interlock and said mating interlock are moved towards each other and into an interlocking relationship due to the motion caused by the deformation itself, said motion finally causing said engagement of said interlock and said mating interlock.

2. The enclosure of claim 1 comprising

support means (66) positioned inside so as to resist movement of said interlock and said mating interlock,

whereby said interlock and said mating interlock are moved towards each other and into interlocking relationship with one another upon inward deformation.

3. The enclosure of claim 1 or 2 characterized in that

said interlock is a projection (25, 63, 61) mounted inside so as not to interfere with the movement of said latch prior to deformation

and said mating interlock is an aperture (47, 59, 62) in said latch which interferes with motion of said latch after deformation.

4. The enclosure of claim 3 characterized in that said projection (25) is mounted on a bracket (23) which is mounted on one of said walls (19).

5. The enclosure of claim 4 characterized in that said latch (41) is mounted for rotation on said lock mechanism (43),

said latch moving to engage said aperture (47) onto said projection (25) when said door (27) is deformed in the vicinity of said lock mechanism.

6. The enclosure of claim 3 characterized in that said projection (61) is mounted to a bracket (60) which is mounted to said door (27),

said bracket surrounding said latch (49).

7. The enclosure of claim 3 characterized in that

said projection (63) is formed into an inner edge of an opening (64) in an edge of said door (27),

said latch (51) operating through said opening.

8. The enclosure of claim 7 characterized in that said opening (64) is in a top edge of said door (27) and said latch (51) is mounted for rotary retraction into and extension out through said opening,

the center of gravity of said latch being lower when said latch is rotated out through said opening so that damage to a latch operating mechanism will not permit the latch to fall open due to gravity.

9. The enclosure of claim 1 or 2 characterized in that

said interlock is a pair of apertures (73, 75) positioned adjacent said latch (67) on a side of said latch away from said door (27) and on the opposite side of said latch,

and said mating interlock is a projection (69) mounted on said latch (67) so as not to interfere with movement of said latch prior to deformation but which interferes with motion of said latch after deformation.