This invention relates to an improved locking system for
containers, in particular, for storage containers.
Background of the Invention
Although the prior art shows locking systems for containers,
none are believed to illustrate the type of device disclosed and claimed.
Storage containers referred to in the present specification
are generally large, walk in boxes similar in size to semi-trailer trucks. The containers
can be stacked and shipped by rail and by ship easily. In addition, such containers
are used as storage devices by end users.
With any such container, maintaining security for the contents
is a prime concern. Because such containers are often left unattended, they become
targets for thieves and other criminals. Thus, the manufacturers and users of such
containers continue to seek and develop better security techniques while the criminal
element continues to develop methods for attacking and circumventing those security
In addition, some storage applications require a seal around
the doors to prevent entry of water, insects and other environmental elements. For
example, paper and furniture storage is best served by a sealed container.
Various types of locking systems have been described in
the prior art.
U.S. Patent No. 5,029,909
entitled "Door Lock Assembly" which issued on July 9, 1991 owned by assignee
of the present invention discloses a protective device for locking the doors of
a storage container using a two bar configuration.
U.S. Patent No. 5,261, 258
entitled "Padlock Protector" which issued on November 16, 1993 owned by
assignee of the present invention discloses a security device, which consists of
an exterior mounted housing for a latch bar, which defines a recess. The recess
provides access to an aperture in the bar by a circular shackle of a disk shaped
padlock. This device operates in much the same fashion as the present invention.
However, it is also believed to be less effective because of its exterior mounting
and structure allows some access to the locking mechanism and the shaft by drills
and hammer devices.
U. S. Patent No.
entitled "Latch and Lock for Trailer Doors" which issued on April 23,
1996 to Kennedy, Jr., and owned by assignee of the present invention, discloses
a concealed latch with an arm attached to a pivot operatively connected to a pair
of locking bars.
However, the devices of the prior art described above are
not completely satisfactory. For example, such devices often require a great deal
of effort to close and latch. In one system, the user is required to bend over and
operate the lever system in a particular sequence. In addition, the devices are
often difficult to operate if the container is not level. Further, these devices
often provide only one locking mechanism making it possible, once the locking system
has been circumvented, for thieves and other criminals to gain entry to the storage
Thus there is a need for a door locking system that is
simple to operate, provides the necessary sealing action and provides a second locking
mechanism that would require additional time to circumvent. The present invention
meets this need.
None of the known prior art disclose the device set forth
Summary of the Invention
It is an object of this invention to provide an improved
locking system for storage containers which provides additional security therefore.
It is a further object of this invention to provide an
improved locking system for storage containers which provides a tight seal against
the elements therefore.
Further objects and advantages of the invention will become
apparent as the following description proceeds and the features of novelty which
characterize this invention will be pointed out with particularity in the claims
annexed to and forming a part of this specification.
Brief Description of the Drawings
The present invention may be more readily described by
reference to the accompanying drawings in which:
Description of the Preferred Embodiment
- Fig. 1 is a perspective front and side view of a storage container embodying
the present invention;
- Fig. 2 is a front view of the embodiment of Fig.1;
- Fig. 3 is a rear view of the embodiment of Fig. 1 in a locked position;
- Fig. 4 is a rear view of the embodiment of Fig. 1 in an unlocked position;
- Fig. 5 is a close up perspective view of the present invention;
- Fig. 6 is a cross sectional front view of the embodiment of Fig. 5;
- Fig. 7 is a cross sectional view taken along line 7-7 in Fig. 6;
- Fig. 8 is a cross sectional view taken along line 8-8 in Fig. 6; and
- Fig. 9 is a close up perspective view of the present invention showing the use
of a padlock and circular lock therewith;
- Fig. 10 is a close up view of the circled area 10 in Fig. 3; and
- Fig. 11 is a cross sectional view taken along line 11-11 of Fig. 10.
Referring more particularly to the drawings by characters
of reference, Figs. 1-11 disclose one embodiment of an improved locking system 10
mounted to one door 11 of a cargo storing container 13 or other door assembly and
the floor thereof. Door 11 and its companion door 12 overlap and open outwardly
with door 12 being closed first and door 11 being closed thereafter. The operation
of such doors 11 and 12 are well known to those of ordinary skill in the art and
will not be further discussed herein. Note that some doors 11 and 12 do not overlap.
In that event, tabs must be added to door 12 to create an appropriate overlap for
locking system 10 to function properly.
As best seen in Figs. 3 and 4, locking system 10 operatively
engages a top rod 14 extending upwardly therefrom, a bottom rod 15 extending downwardly
therefrom and a side lock rod end 16. Rods 14 and 15 and lock rod end 16 are mounted
on the interior side of door 11. Rod 14 engages the upper lock rod end 17 and rod
15 engages the lower lock rod end 18. Lock rod ends 16, 17 and 18 have a locked
position illustrated in Fig. 3 wherein the lock rod ends extend just beyond the
periphery of door 11 to engage the interior side of door 12, a ceiling 19 and a
floor 20, respectively, and an unlocked position illustrated in Fig. 4 wherein the
lock rod ends 16, 17 and 18 do not extend beyond the periphery of door 11. Locking
system 10 slides rods 14 and 15 and lock rod end 16 between the two positions as
desired. To open system 10, lock rod ends 16, 17 and 18 must be disengaged.
To align lock rod ends 16, 17 and 18, a side lock rod guide
21, a top rod guide 22 and a bottom rod guide 23 and are provided mounted on door
11 proximate to the periphery thereof. Lock rod ends 16, 17 and 18 preferably engage
a side lock rod guide 21, a ceiling lock rod guide 22 and a floor lock rod guide
Preferably, each lock rod end 16, 17 and 18 include a sloped
edge 24, 25 and 26, respectively, which facilitate alignment of each lock rod end
with a respective lock rod guide 21, 22, 23. In addition, preferably, lock rod ends
16, 17 and 18 are doubled in thickness at the distal end thereof. The extra thickness
provides further security by strengthening an inherent access point where lock rod
ends 16, 17 and 18 cross the periphery of door 11, i.e. where thieves often employ
cutting tools. In the presently preferred embodiment, the rods are comprised of
solid square steel bar and the lock rod ends are cast as a single piece or may be
manufactured by welding two square bars together.
Turning now to Figs. 5-8, the operation of locking system
10 is further detailed. As seen in Fig. 5, locking system 10 includes a box like
housing 27 having a front panel 28. Front panel 28 includes an integral flange 29
extending outwardly from housing 27, which provides for mounting said housing on
an opening in door 11. Housing 27 and integral flange 29 are, preferably, made from
heavy gauge metal. For those storage containers 13 made of aluminum or a like material,
locking system 10 is secured to door 11 by bolts extending through flange 29 which
are secured to door 11 by nuts which are, most preferably, welded to the bolts for
A handle 30 rotatably engages an axle 31 extending through
front panel 28. One feature of the present invention is to utilize a relatively
short handle 30 to minimize the prying leverage available to a potential thief.
In the most preferred embodiment, locking system 10 is positioned on door 11 whereby
handle 30 is at a height convenient for users in a normal standing position.
Another ergonomic feature is that the direction of rotation
of handle 30 to close door 11 is, preferably, a downward motion. Such a downward
motion affords a user the ability to bear down on handle 30 with their entire body
weight to assure engagement of lock rod ends 16, 17 and 18.
Further, in the presently preferred embodiment, the lock
rods 14 and 15 and the lock rod ends 16, 17 and 18 are designed and weighted to
fall to the open position thereby preventing doors 11 and 12 from accidentally locking
a person inside, and further allowing operation of same with a minimum of force.
As best seen in Fig. 6, axle 31 operatively engages a lower
cam plate 32 mounted within housing 27, which extends laterally therefrom. In the
illustrated embodiment, lower cam plate 32 is trapezoidal though those skilled in
the art will recognize that the particular shape is not important.
The lower cam plate 32 engages cam link 33. Cam link 33
engages upper cam plate 34. This establishes an operative link between handle 30,
axle 31, lower cam plate 32, cam link 33 and upper cam plate 34.
At two corners 35 and 36 of lower cam plate 32 a side rod
link 37 and bottom rod link 38, respectively, are mounted, preferably by bushing
39. Additionally, at corner 40 of upper cam plate 34 a top rod-locking link 41 is
mounted, preferably by bushing 39. The use of rod links 37, 38 and 41 permits the
user to adjust the length of the rod/link combination to compensate for dimensional
variations in storage containers.
Further, lower cam plate 32 includes an anti-torque spacer
42 which maintains lower cam plate 32 in parallel alignment to housing 27 even if
excessive force is applied to lower cam plate 32 via axle 31 and handle 30. Anti-torque
spacer 42 also restricts the entry of outside elements into housing 27.
As best seen in Fig. 5, rod links 37 and 38 and rod-locking
link 41 extend through openings 43 in sidewalls 44 of housing 27. In the presently
preferred embodiment, rod links 37 and 38 and rod-locking link 41 are all comprised
of steel flat bar and are joined via welding to lock rods 14 and 15 and lock rod
end 16. Those skilled in the art will recognize the suitability of other materials
for the use described herein.
In Fig. 6, locking system 10 is shown in the locked position.
To unlock, a user rotates handle 30, and hence lower cam plate 32, via axle 31,
which rotates upper cam plate 34 via cam link 33, counter clockwise as shown by
arrow 45 wherein rod links 37 and 38 and rod-locking link 41 are pulled inwardly
into housing 27 as shown by arrows 46 thereby retracting lock rods 14 and 15 and
lock rod end 16 to the unlocked position.
A further advantage of locking system 10 is that retraction
of rod links 37 and 38 and rod-locking link 41 into housing 27 affords installation
of locking system 10 onto doors 11 and 12 through the opening, which is cut into
the front of door 11. Such a construction assists in installation since housing
27 is a one-piece installation.
Extending forwardly from lower cam plate 32 is a single
piece, thick locking tab 47 having a lock hole 48 extending therethrough. Tab 47
extends through an arcuate gap 49 into a recess 50 extending inwardly from front
plate 28 to center plate 51 parallel to front plate 28. Tab 47 passes through a
slot in lower cam plate 32 and is welded to the back of lower cam plate 32. The
ends of arcuate gap 49 provide stops, which limit the travel of tab 47, and hence
cam plates 32 and 34, thereby providing the end points for the locked and unlocked
Additionally, a secondary lock tab 52 extends forwardly
from rod-locking link 41 having a lock hole 53 extending therethrough. Lock tab
52 extends through a slot 56 in center plate 51 into a recess 57 extending inwardly
from front plate 28 to center plate 51 and is welded to the face of rod-locking
link 41. A stationary lock tab 54, having a lock hole 55 extending therethrough
is welded to the face of center plate 51 in recess 57 where lock hole 55 is aligned
with lock hole 53 in lock tab 52 with locking system 10 in the locked position.
As best seen in Fig. 9, a circular lock 58 engages lock
hole 48. Recess 50 is adapted to engage circular lock 58 and thereby prevent movement
of tab 47, and hence lower cam plate 32 and upper cam plate 34, when circular lock
58 in engaged with tab 47. Thus the entire body of circular lock 58 and recess 50
act to prevent movement from the locked position to the unlocked position until
circular lock 58 is removed. Thus, movement of lower cam plate 32 and upper cam
plate 34 and lock rod ends 16, 17 and 18 are not solely dependent upon the structural
integrity of tab 47. A padlock 59 engages lock hole 53 and lock hole 55 in tabs
52 and 54, respectively, preventing movement of rod-locking link 41, and hence lower
cam plate 32 and upper cam plate 34, preventing movement from the locked position
to the unlocked position while padlock 59 is engaged. Recess 57 is partially covered
by lock pocket cover 60 and lock pocket cap 61 preventing access to tabs 52 and
54 and padlock 59. Recess 50, lock pocket cover 60 and lock pocket cap 61 also provide
weather protection for locking system 10.
As seen in Fig. 10, locking system 10 may alternately be
made utilizing an elongated cover plate 62 and back plate 63 to create a recess
64. Handle 30 is replaced with a longer handle 65, which is mounted to the lower
cam plate 32, and extends into recess 64. Guard plate 66 allows the handle to be
operated and prohibits access to the locking systems inner workings by potential
Although only certain embodiments have been illustrated
and described, it will be apparent to those skilled in the art that various changes
and modifications may be made therein without departing from the spirit of the invention
or from the scope of the appended claims. For example, the present invention can
be used in construction of new storage containers but also can be provided in a
kit form for use in retrofitting existing storage containers.