Door latch mechanism

A lock mechanism for securing the cabinet of a security validator. A latch handle is maintained within a recess within a latch housing. The handle is pivotal about an axis and moves within an opening in the latch housing, transversing a slot within the housing. A lock cylinder has a plate connected thereto and adapted for positioning within the slot to engage and maintain the handle within the recess and slightly depressed therein. The handle is spring-biased to normally urge it from the recess. A freely rotatable disc is positioned before the lock cylinder to prevent unauthorized access thereto.

TECHNICAL FIELD 
The invention herein resides in the art of locking devices. More 
particularly, the invention is adapted for securing cabinetry such as the 
cabinets used for maintaining security validators and changers. Such 
cabinets, maintaining large volumes of cash therein, pose an invitation to 
wrongful entry. The instant invention is adapted for securing such 
cabinets and defeating unauthorized access by means of the unique 
combination of elements hereinafter described. 
BACKGROUND OF THE INVENTION 
For centuries, man has perceived and developed various types of locking 
devices to secure for himself, to the exclusion of others, his prized 
possessions. The nature and complexity of the lock has generally been 
dependent upon the nature of the object to be secured, its structure, 
value, size, and the like. While there are some universal characteristics 
attributed to locks in general, peculiarities and sophistication of the 
locks are determined, primarily, by the perceived determination of others 
to gain unlawful access. Currency validators, such as coin changers, 
maintain therein significant volumes of cash. Further, such currency 
validators are, of necessity, placed where the public may freely travel, 
requiring that the validators themselves include foolproof locking 
mechanisms to prevent any of the large number of people who frequent such 
machines from making unlawful or illegal withdrawals. 
While it is desired that a locking mechanism for a currency validator be of 
sufficient integrity to prevent unauthorized entry, the locking mechanism 
must be of sufficient simplicity to allow authorized personnel to gain 
ready access to the validator for servicing. 
Previously known locks or locking mechanisms for security validators have 
been formed of a zinc die casting, the same being suprisingly easy to 
defeat by breakage, drilling, or the like. Further, in certain instances, 
the locks have been connected to the cabinet by exposed fasteners, such as 
screws or bolts, which fasteners might readily be removed by a thief. 
Where key locks are used, the lock cylinder has typically been 
unprotected, susceptible to defeat by a drill bit or cylinder puller. Yet 
further, previously known locking mechanisms have left the lock cylinder 
unrestrained such that it is susceptible to a punch, driving the cylinder 
from its locking position. Further inherent with previously known locking 
mechanisms is that such mechansims are of a specific design, adapted for 
receiving but a single lock cylinder, and incapable of being adapted for 
acceptance of various types of lock cylinders. Accordingly, a customer 
desiring a specific lock cylinder for implementation in its security 
validator would mandate a substantial redesign of the entire mechanism to 
obtain the desired result. 
Finally, known locking mechanisms for security validators have often left 
the latch handle sufficiently exposed as to invite prying with a 
screwdriver or other sharp implement for ultimate defeat. 
DISCLOSURE OF THE INVENTION 
In light of the foregoing, it is a first aspect of the invention to provide 
a door latch mechanism of stainless steel construction, uneffected by 
attempts at drilling and breaking. 
Another aspect of the invention is the provision of a door latch mechanism 
wherein there are no exposed fasteners interconnecting the mechanism to 
the cabinet which it seeks to secure. 
A further aspect of the invention is the provision of a door latch 
mechanism wherein the lock cylinder is protected and maintained in such a 
manner as to prevent drilling, prying, pulling, or punching the cylinder 
from its housing. 
Yet an additional aspect of the invention is the provision of a door latch 
mechanism wherein the cylinder housing is adapted for receipt of any of 
numerous lock cylinders. 
A further aspect of the invention is the provision of a door latch 
mechanism wherein the latch handle is received within a recess of close 
tolerance, impeding any effort of prying or the like, and wherein the face 
of the latch handle is slightly recessed below the face of the front plate 
to impede prying and to compensate for alignment irregularities resulting 
from dimensional and angular deviations. 
Yet an additional aspect of the invention is the provision of a door latch 
mechanism of high integrity, but which is readily constructed of 
state-of-the-art elements and adapted for implementation with existing 
cabinetry. 
The foregoing and other aspects of the invention which will become apparent 
as the detailed description proceeds are achieved by a latch assembly, 
comprising: a latch housing; a handle received within a recess within said 
latch housing, said handle being pivotal about an axis; and a spring in 
engagement with said handle and urging said handle from said recess. 
Other aspects of the invention are attained by a device for securing a 
cabinet door, comprising: a latch housing having a recess therein, said 
latch housing being received by said cabinet and being substantially flush 
with a surface thereof, said latch housing having an opening therein and a 
slot transversing said opening; a handle received within said recess and 
pivotal within said opening about an axis, pivotal movement of said handle 
transversing said slot; a lock cylinder housing connected to said latch 
housing and having a lock cylinder maintained therewithin; and a locking 
plate connected to said lock cylinder and selectively positional within 
said slot, engaging said handle, and maintaining said handle within said 
recess.

BEST MODE FOR CARRYING OUT THE INVENTION 
Referring now to the drawings and more particularly FIG. 1, it can be seen 
that a latch assembly according to the invention is designated generally 
by the numeral 10. A thin front plate 12 defines the major periphery of 
the latch assembly 10, and has extending from the back portion thereof a 
latch housing 14. The thickness of the front plate 12 varies with the 
degree of security desired. Preferably, the plate 12 mounts substantially 
flush with the cabinetry as shown in FIG. 3. Screw holes 16 are provided 
in the latch housing 14 for mounting and securing the assembly 10 to the 
back 48 of the latch rail as shown in FIG. 3. The structure of the latch 
rail will be described hereinafter. Suffice it to say at this time that 
the latch housing 14 receives a handle therewithin which, when closed, is 
flush with the surface of the front plate 12. It is also contemplated that 
the handle may be slightly recessed with respect to the front plate 12 to 
further impede prying. At this time, the handle covers the screws passing 
through the screw hole 16, such that the fasteners are not accessible. 
The latch housing 14 is characterized by latch head passage 18 through 
which the head of the latch may pass as it is pivoted about a pin passing 
through the hole 20. This structure will become further apparent in 
reference to FIG. 2. 
A circular opening 22 is provided in the front plate 12 through which a key 
may be inserted for making access to a key cylinder. The key cylinder is 
maintained within a cylinder retainer housing 24, only half of which is 
shown in the illustration of FIG. 1. It will be appreciated that an 
identical half (not shown) may be interconnected with the illustrated half 
of the cylinder retainer housing by means of screws or pins received in 
the hole 26. An inner retaining flange 28 characterizes the front portion 
of the housing 24 nearest the opening 22, while an outer flange 30 
characterizes the rearward portion of the cylinder housing 24. A lock 
cylinder is maintained between the flanges 28,30, and retained therein by 
secured engagement between the two halves of the cylinder retainer 24 by 
means of screws or pins passing through the holes 26. 
It will also be noted from FIG. 1 that a slot 32 characterizes the top end 
portion of the latch housing 14 and perpendicularly communicates with the 
opening 18. As will be described with respect to FIG. 2, this slot 32 
receives a cylinder lock cam plate for locking the head of the latch which 
pivots through the latch head passage 18 and about a pin received in the 
opening 20. 
With reference now to FIG. 2, it can be seen that a latch handle 34 is 
pivotally maintained about a latch pin 36, received in the opening 20 of 
the latch housing 14. A latch handle torsion spring 38, maintained about 
the pin 36, urges the handle 34 into a slightly opened position, such that 
the handle 34 protrudes slightly from the cavity within the housing 14 in 
which it is maintained when in the locked position. 
As will be discussed hereinafter, the latch handle 34 is shown in two 
positions in FIG. 2, in the opened position by the intermittently dashed 
lines, and in the closed position by the continuously dashed lines. 
A key-actuated lock cylinder 40 is maintained in the cylinder retainer 
housing 24 as shown. A security disc 42 is provided in juxtaposition to 
the opening 22 and maintained between the flange 28 and the back of the 
front plate 12. The security disc 42 is preferably of hardened steel, and 
is freely rotatable within its confined position. It is, of course, 
provided with a slot therein such that a key may pass through the slot and 
into the lock cylinder 40. In any event, being freely rotatable, a drill 
may not be used for making access to the cylinder 40, for the drill will 
merely rotate the security disc 42 upon contact and will not cut 
therethrough. Similarly, the disc 42 prevents access by a cylinder puller. 
It is a particular attribute of the instant invention that the cylinder 
housing 24 is adapted for receipt of any of numerous lock cylinders. In 
other words, the spacing between the retaining flanges 28,30 is sufficient 
to accommodate a variety of lock cylinders so long as cylinder spacers or 
shims 44 are used to take up slack space within the housing. 
A locking nut 46 threads upon the lock cylinder 40, securing the same 
within the cavity of the housing 24, while further securing the latch 
assembly 10 to the latch rail. As shown in FIG. 2, and as will be more 
apparent from FIG. 3, a latch rail receives the latch assembly, such rail 
consisting of a back rail portion 48 and a front rail portion or channel 
50. It is the front channel portion 50 which is housed to receive the 
latch assembly 10 such that the front plate 12 is flush therewith. 
As further illustrated in FIG. 2, a lock cam plate 52 is connected to the 
cylinder 40, and rotatable therewith. The cam plate 52, in the locked 
position, is maintained within the slot 32 of the housing 14, retaining 
the handle 34 in the locked position as shown by the dashed lines of FIG. 
2. 
FIG. 3 illustrates a cross-sectional view of the latch rail of the 
invention showing the same interconnected with the two doors, one on 
either side of the cabinet, being secured. As can be seen, a right door 54 
and a left door 56 are shown as being closed upon the latch rail 
comprising a back 48 and a front channel member 50. Each of the doors 
54,56 includes respective channel door edges 58,60, such door edges 
defining cavities in the channel portions. A slide bar 62 is maintained by 
retaining rings or other suitable retainers 64, such retainers being 
affixed to the back of the latch rail 48. The slide rail 62 has an 
appropriate slot therein to allow the slide bar 62 to move vertically. The 
slide bar 62 is provided with a plurality of locking wings or bars 66,68, 
also shownn in FIG. 2, which locking wings pass through slots 70,72 in the 
door channels 58,60 and the latch rail members 48,50. While only a pair of 
locking wings have been shown in the drawings, it will be understood that 
each door may engage with two or more such locking wings to effect secured 
engagement of the doors with the latch rail 48,50. 
As shown in FIG. 2, the latch rail has attached thereto a latch rail pin 
74, which pin is positioned for engagement with the head of the latch 
handle 34 to effectuate upward or downward movement of the slide bar 62 to 
effect locking or unlocking of the doors 54,56. As illustrated, the latch 
rail pin 74 may be contacted by the opening cam surface 76 at the head of 
the latch handle 34 for downward unlocking movement, as shown by the 
position in FIG. 2 of the handle 34, illustrated by the intermittently 
dashed line. Locking of the doors 54,56 is achieved by engagement of the 
closing cam surface 78 of the latch head and the upward movement of the 
slide bar 62 to the totally closed position shown by the latch handle, as 
illustrated with the totally dashed lines. 
It will be appreciated that when the slide bar 62 has been moved upwardly, 
the locking wings 66,68 go to the top of the slots 70,72 so that the doors 
cannot be opened. When the locking wings 66,68 have been moved downwardly 
by the upward pivotal movement of the latch handle 34, the locking wings 
66,68 are moved to the bottom of the slots 70,72 such that the doors 54,56 
can be opened with the wings passing through the slots as the doors open. 
As will further be noted in FIG. 2, the opening cam 76 has at the end 
thereof a flat surface 80 which, in the locked position of the latch 
handle 34, is withdrawn past the slot 32. In this position, the latch rail 
pin 74 has urged the slide bar 62 upwardly such that the locking wings 66 
are at the tops of the slots 70,72, locking the doors 54,56 against the 
latch rail 48,50. A key inserted through the slot in the security disc 42 
may then be used to rotate the cylinder 40, rotating the lock cam plate 52 
into the slot 32, against the surface 80, and thereby preventing 
retraction of the handle 34 from its recess. 
It will also be appreciated that the cam plate 52, received within the slot 
32, acts as a brace for the cylinder 40, preventing the same from being 
punched out and thereby rendered inoperative. 
When the lock cylinder 40 is again rotated to remove the cam plate 52 from 
the slot 32, the spring 38 will urge the handle 34 slightly out of its 
recess such that it may be grasped by the operator and pivoted upwardly, 
moving the latch rail pin 74 downwardly to disengage the doors 54,56. 
Thus it can be seen that the objects of the invention have been satisfied 
by the structure presented hereinabove. While in accordance with the 
patent statutes only the best mode and preferred embodiment of the 
invention have been presented and described in detail, the invention is 
not limited thereto or thereby. Accordingly, for an appreciation of the 
true scope and breadth of the invention, reference should be had to the 
appended claims.