Note: Descriptions are shown in the official language in which they were submitted.
4883
sAcKGRouND OF INVENTION
(a) Field of the Invention
The present invention relates to a!n improved
safety lock system having movable locking bars and fixed
pivotal cams whereby predetermined ones of a plurality
of vertically slideable storage elements are 1ocked
when a selected one of the storage elements iB displaced
a predetermined distance.
(b) Description of Prior Art
Various interlock systems are k.nown for use
with filing cabinets wherein drawers may be locked or
prevented from opening when a first drawer is withdrawn
from the cablnet. An example of this prior art is a
file interlock system as shown in U.S. Patent No~ -
3,900,236 issued August 19, 1975 and wherein there is
shown a system comprising lock bars having cam members
secured thereto and wherein the lock bars are displace-
able to an immovable position against a cabinet wall
to prevent withdrawing any file drawer of the cabinet
once a file drawer is opened.
SUMMARY OF THE INVENTION
The present invention relates to an improvement
of such system whereby it may be possible to bypass par-
ticular drawers in a filing cabinet or other type system
having slideable storage elements and wherein the lock
system may be modified during use to remove the inter-
lock from particular ones of the storage elements. It
is also desired to provide such a locking system which
operates on a different principle whereby the system is
more economical to construct and assemble. It is also
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desirable to have a locking system which need not he
restricted for use in a cabinet hous.ing but which may
be adapted to a plurallty of verti.cally sLl~eable stor-
age element~ mounted in an open frame. Furthermore, it
is desirable to have a system which would prevent two
drawers ~rom being withdrawn simultaneously.
Accordingly, a featuxe of the present inven-
tion is to provide an improved safety lock systern where-
in selected ones of a plurality of vertically sli.de-
able storage elements are arrested when a particular one
of the storage elements is displaced a predetermined
distance by arresting cam elements and movable locking
bars disposed between the cam elements.
A further feature of the presen-t inventi.on is
to provide a safety lock system for use with a plurality
of vertically stacked slideably retained storage elements
of different sizes and wherein selected ones of the
storage elements, at random, may be bypassed from the
lock system.
According to a further feature of the present
invention, there is provided a safety lock system for
use in a filing cabinet which prevents two drawers from
being withdrawn simultaneously.
Another feature of the present invention is to
provide a safety lock system which is economical to
produce and easy to assemble.
According to the above features, from a broad
aspect, the present invention provides a safety lock
system for vertically stacked slideably retained storage
elements, said system comprising one or more locking
bars vertically slideably retained in alignment in ver-
tical support guide means, two or more cam elements
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pivotally secured on a respective fixed pivot axis to
said support gulde means adjacent an opposed end of each
said locking bars, each said cam elements having a cam
portion retained in planar alignment with said locking
S bars and an activating arm portion for rotatlng said
cam portion ahout said fixed p:ivot axis, a displaceable
space below each cam element portion defined between
one of said locking bar opposed ends and said cam por-
tion, an engaging member secured to one or rnore of said
storage elements to engage and displace said activating
arm portion of an associated cam element by predeter-
mined displacement of a s-torage element having said
engaging member to cause rotation of said associated
cam portion to slidingly displace said locking bars
thereabove through said displaceable space in immovable
contact with -their associated cam elements and arrest
sliding displacement of said locking bars therebelow to
maintain them in immovable contact with their associated
cam elements to thereby immobilize all other cam ele-
ments against rotation displacement and thereby prevent
slideable displacement of all other of said storage ele
ments having an engaging member.
According to a further broad aspect of the
present invention, there is provided a method of lock-
ing predetermined ones of a plurality of vertically
slideable storage elements when a selected one of said
storage elements is displaced a predetermined distance,
said method comprising (i) securing a lock support means
vertically adjacent a displaceable side wall of said
stacked storage elements, ~ii) providing sliding bars
for slideable displacement in alignment in said support
means, (iii) providing cam elements pivo-tally secured
on a respective fixed pivot axis to said support means
adjacent opposed ends of said sliding bars- tiv) ro-tating
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a selected one of said cam elements by prede-terrni.ned
sliding displacement of a selected one of said storage
elements to cause sl.iding displacement of said locking
bars above said rotated selected cam element, and
(v) arresting said locking bars below said selected one
of said storage elements by said rotated cam element -to
arres-t all other cam elements to thereby prevent slide-
able displacement of the re~ainder of said predeter-
mined ones of said plurality of storage elements.
BRIEF DESCRIPTION OF ~RAWINGS
A preferred embodiment of the present inven
tion will now be described with reference to the example
thereof illustrated in the accompanying drawings in
which:
FIGURE 1 is a perspective fragmented view of the
safety lock system illustrating the operation thereof,
FIGURES 2A to 2C are fragmented perspective
views illustrating the operation of the cam elemen-ts
and locking bars showing the displacement of the locking
bars above and below a rotated cam element,
FIGURE 3 is an exploded view showing the
assembly of the cam elements,
FIGURE 4 shows the cam element assembled on
its support plate;
FIGURE 5 is a plan view showing the construc-
tion of a cam element,
FIGURE 6 is a top section view showing the
cam element mounted in a guide channel secured to a file
cabinet wall and showing the position of the engaging
pin secured to a file drawer, and
FIGURES 7A and 7B are end views showing the
end of the locking bar in section and in fragmented
plan view.
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DESCRIPrrION OF PREFERRED EM:BODIMENTS
Referring now to the drawings and more parti-
cularly to Figures 1 and 2A to 2C, there is shown gen-
erall~f at 10, the safety lock system of the present in-
vention. The safety lock system comprises one or more
locking bars 11 vertically slideably retained in planar
alignment in a vertical suppor-t guide means, herein
constituted by a support channel 12~ The support channel
12 is vertically securable to a support frarne, as shown
in Figure 6, to the inner side wall 1~ of a filing cabinet
15 and disposed adjacent a side wall 16 of a plurality
of vertically stacked slideably retained storage elements
13, herein file drawers displaceable on guide rails.
Two or more cam elements 17 are pivotally
secured on a respective fixed pivot pin 18 secured in
the guide channel 12 and extending between the back wall
12'of the channel 12 and a front wall 18'of a support
plate 19 removably secured in front of the guide channel
12.
As shown more clearly in Figures 2A to 2C
and Figure 6, the locking bars 11 are elongated straight
flat members having opposed elongated edge grooves 20 and
the opposed er.ds 21 each have a cam engaging surface
22 and alocking bar support surface 23. Locking bars
11 are slidingly retained and displaceable within the
guide channel 12 by means of side rails 24 secured
to each opposed side wall 25 and formed integral with
the back wall 12'of the guide channel. Thus, the
locking bars 11 can move up and down along the side rails
24 and are maintained in a common plane.
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The cam engaging surface 22 is a concave end
cavity in each of the flat opposed end walls 21 of the
locking bars. I'he cavity 22 has opposed slQping walls
26 terminating at a central apex point 27. The locking
bar su,pport surface 23 is constltuted by an end arm
28 provided on opposed sides of the concave end cavity
or cam engaging support surface 22. ~rhe end arms 28
of the locking bars abut or res-t on the arms of the
adjacent locking bar and the cam element 17 is disposed
between the loc]cing bars in the space clelineated between
opposed concave end cavities 22.
Referring now to Figures 3 to 6, the construc-
tion of the cam element 17 will now be described. ~s
shown more clearly in Fiyures 3 and 5, the cam element
17 is an integrally formed part comprising a cam portion
30 and an activating arm portion 31 and both these por~
tions are spaced apart by a connecting body 32 having a
through bore 33 ex-tending therethrough to receive the
pivot pin 18 therethrough.
The cam portion 30 is a dual cam portion com-
prising diametrically opposed shoulder sections 3~
lying in a horizontal plane 35 when the cam element 17
is in its non-ac~ivated position, that is to say, its
associated storage element 13 is not displaced or with-
drawn fr~m the stack. The cam portion 30 is substan-
tially of an elliptical shape and has a fla-t contour
side wall 36 whereby to provide flush engagement with
the flat wall of the cam engaging surface or cavity 22
of the locking bars 11.
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As shown in Figure 5, the activating arm por-
tion 31 is a fork shaped element having opposed arms 37
which are enyageable by an engaging member, herein an
engaging pin 38 (see Fig. 6) secured to an associated
5 one of a plurality of storage elements 13. The central
longitudinal axis 39 of the activating arm portion 31
extends at 45 from the central longitudinal axis 35 of
the cam portion 30. Therefore, with the axis 35 dis-
posed horizontally, as the engaging pin 38 is displaced
10 in the plane of the sliding storage element 13, the pin
38 will rotate the activating arm portion 31
~rom the pos:ition shown in Figure 5 to a position where
its central longitudinal axis 39 lies along th~ axis 39'
(as shown in Fig. 4) resulting in a 90 displacement
15 thereof. This displacement causes the cam portion 30
to rotate whereby its central longitudinal axis 3S now
lies on the vertical axis 40. The operation of the cam
and the locking bars 11 will be described later.
As previously described, the cam element 17
20 is rotatably supported on a pivot pin 18 which is secured
between the back wall 12'of the guide channel 12 and
the front wall 18' of -the support plate 19~ As shown
in Figure 3, the pivot pin 18 is provided with a cylin-
drical main body portion 40 having an attachment end
25 portion 41. A locating sleeve 42 is provided about the
main body portion 40 adjacent a locating end portion 43
of the main body portion 40. The locating sleeve 42
provides retention of the cam element 1~ for precise
positioning of the pivot pin 18 within its through bore
30 33. me pivot pin extends between the back wal:L 12' of
the guide channel 12 and the front wall 18' of
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the support plate l9q The attachment end ~1 of the pin
ex-tends through a securemen-t hole ~ provided in -the
front wall 18' of the support plate 19 and is rivetted
therein. The locating end portion ~3 of the pin is
received freely in a support hole 45 formed in the back
wall 12'of the guide channel 12 whereby the plate 19
is removable from the channel 12.
Referring again to Figure 3, -there is shown
the construction of a retention spring 50 which is
secured intermediate the end surface 49 of the activa-
ting arm portion 31 of the cam 17 and the inner surface
~8 of the end wall 18'of the support plate 19. The
retention sprin~ 50 has a curvate shape whereby to main-
tain pressure between the end surface ~9 of the cam 17
and the support plate 19 and -therefore acts as a pres-
sure washer. However, the main purpose of the spring
50 is to maintain the actuating arm portions 31 of the
cam elements in their respective non-actuated or
actuated positions, that is to say, along the axes 39
or 39' of Fig. 5, when its associated storage element 13
is fully closed or displaced a predetermined distance.
The spring 50 is provided with a contoured
hole 51 adjacent a lower end thereof whereby it can
: be localized within an indexing tab 52 formed about
the through bore 33 on the end surface ~9 of the cam
element 17. The localizing contour hole 51 ali~ns the
longitudinal axis of the spring 50 co-extensive with
the longitudinal central axis 39 of the activating arm
portion 31. ~he free end 53 of the spring 50 is provided
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with engageable means, herein a hole :~orme~ as a con-
cave depression 5~ to frictionally engage with two hold-
ing means, herein being convex punch tabs 55 provided
in the inner surface ~8 of the support plate 19 and posi-
tioned such as to retain the spring 5p with its central
longitudinal axis aligned 90 apart and coinciding with
the axes 39 and 39' as shown in Figure 5 whereby to
maintain frictional retention of the cam element 17 with
the cam portion 30 thereof extending in the horizontal
plane 35 (see Figure 5) and in the vertical plane 40
when displaced thereto by the engaging pin 3~3.
As shown in Figures 3 and ~, the support
plate 19 is provided with opposed securement wings 56
disposed parallel to the front wall 18' and formed in-
tegral with transverse side walls 57. A hole 58 is
provided in each of the wings 56 to receive a secure-
ment screw 59 therethrough to secure the support plate
19 to the attachment flanges 2~' of the guide channel
12 (see Figure 6) and formed integral with the side
rails 24. Access -to the securement screws 59 is pro-
vided through apertures 60 axially aligned with the
holes 58 and formed in the front wall 18'.
Referring to all the drawings, and more par-ti-
cularly to Figures 1 and 2A to 2C, the operation of the
safety lock system will now be described. In -the
assembly of the safety lock system, a bottom cam element,
such as shown at 17' in Figure 2A, is secured to the
guide channel 12. Thereafter, a first locking bar 11'
is shaped fitted into the channel with the cam engaging
cavity 22 resting on the horizontally disposed cam por-
tion 30 of the cam element 17'. As shown in Figures 7A
and 7B, each locking bar is provided with flexible inner
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elongated retain.ing ridges 20' which flex inwardly to
locate the opposed side rails in a respective one of the
opposed elongated edge groups 20 for sllding retention
of the locking bars therewith. rrhereafter, a second
lowermost cam element 17" is secured to the guide
channel and a second lowermost locking bar 11 positioned
thereover and this sequence continues along the guide
channel 12 up to the predetermined number of cam elements
required to lock a predetermined number of vertically
stacked slideably retained storage elements 13.
As shown at the bottom of Figure 1, the
opposed ends 21 of the end arms 2~ are in abutment with
each other and are very closely spaced to each other
when the locking system is assembled and a displaceable
space 61 is formed between the contour side wall 36 of
the cam portion 30 and the flat wall of the cam enyaging
surface 22 of the locking bar positioned thereunder.
he displacement space 60 is spaced from the contour
side wall 36 of the cam portion 30 a distance sufficient
~ 20 to permit the cam portion 30 to be displaced to its
vertical position on -the vertical axis 40 and it is equal
to the distance X as shown in Figure 5.
With all of the storage elements 13 having
engagement pins 38 secured thereto resting in their
.;25 stored position, all of the engaging pins 38 are resting
in the position as shown in Figure 2A and the safety
lock system is inactive. As soon as one of the storage
elements 13 is pull.ed outwardly a predeterminecl distance,
its associated engaging pin, such as 38' in Figure 2B,
will be displaced horizontally with respect to the cam
element and engage the arm 37' of the activating arm
portion 31 causing the cam portion of the cam element 17"
to rotate 90 and locate itself on the vertical axis ~0.
This rotating movement of the carn portion 30 causes all
383
of the uppermost locking bars 11 -to move upwardly into
the displaceable space 60 unti] they abut or very closely
space to the side wall 36 of the cam elements 17 located
thereabove. Thus, the locking bars 11 above the rotated
cam 17" and the cam elements thereabove are in irnmovable
position. The locXiny bars below the rotated cam elernent
17", for example locking bar 11" as shown in Figure 2B,
cannot be displaced as its cam engaging support cavi-ty
22 is resting onto the side wall of the cam portion 30
of the cam element therebelow. Thus, all of the cam
elements therebelow and locking bars therebelow are
arrested from further movemen-t through the cam portion 30
of the rotated cam element 17" and the entire cam and
locking bar assembly is loc]ced through that rotated cam
element 17". Therefore, no other storage elements 13
having engagement pins 38 thereon can be displaced as
the engaging pin 38 will be arrested by the actuating arm
portion 31 of the other cams which are all locked or
arrested by the locking bars. When the displaced storage
element 13 is slid back into its storage position, its
engaging pin 38 will engage with the arm 37" (see Figure
2B) and displace the actuating arm portion 31 back to
its inactive position on the axis 39 (see Figures 4 and
5). Thus, the locking bars above the rotated cam element
? 25 17 will drop to its unlocked position, -that is, each bar
will rest on their lower ends on their associated cams
17 and the lowermost bars will not moveO All of the cam
elements are therefore in their inactive position with
their cam portions 30 extending horizontally.
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As previously described, i-t is not possible
wi-th the locking system of the present invention to
withdraw two slideable storage retainlng elements 13
simultaneously~ More precisely, referring to Figure 2A,
it can be seen that if two of the sliding elements were
withdrawn simultaneously, each of their engaging pins
38 would abut against one of the arms 37 of their res-
pective cam elements 17. This would skart a clockwise
rotation of the opposed shoulder sections 34 with the
lower cam element 17' causing the ]ocking bar 11' -to
move upwardly while simultaneously the upper cam element
17" would apply downward pressure on the upper portion
of the locking bar 11'. These opposed forces would
cancel out the movement of the locking bar thereby pre-
venting the drawers from being withdrawn. In a situation
where a drawer may be only slightly open with its engaging
pin 38 positioned intermediate the opposed arms 37' and
37" of the activating arm portion 31, and a further
; drawer is pulled out, the force exerted on the locking
bars will cause the shoulder sections 34 of the cam ele-
ment slightly displaced to reassume its horiæontal posi-
tion whereby the activating arm portion 31 will retract
the drawer into a fully closed position.
It is within the ambit of the present inven-
tion to cover any obvious modifications of the preferred
embodiment thereof disclosed hereinabove, provided such
modifications fall within the scope of the appended
claims.
