Anti-tip mechanism and method for providing anti-tip device

A latching mechanism is provided for use with a cabinet having a number of drawers in stacked relation, to permit the opening of only one drawer at a time. The mechanism is suited for retroactive fitting to existing cabinets, and for original equipment manufacture. The mechanism components are mounted on the drawer slide, the active components being secured by way of a bracket to the stationary channel member of the slide, and an actuating pin for cooperation therewith secured to a movable drawer slide. A lock and locking systems components also may be provided. A method of constructing an anti-tip locking mechanism is also provided.

FIELD OF THE INVENTION 
This invention is directed to a safety mechanism for use with cabinets and 
the like having slideable drawers, and in particular to an anti-tip 
device, for use with such cabinets, and to its method of use. 
BACKGROUND OF THE INVENTION 
Sliding drawer cabinets having a plurality of drawers in mutually stacked 
relations are in widespread use. While many such cabinets are provided 
with anti-tip arrangements, to permit opening of only one drawer at a time 
as a precaution against tipping of the cabinet, there exist many cabinets 
that are not thus equipped. 
Cabinets equipped with anti-tip devices generally require special provision 
of an internal guide channel within the interior structure of the cabinet, 
for installation therein of an arrangement of motion-transmitting slide 
bars. Furthermore, the flexible construction of pressed light sheet metal 
cabinets does not lend itself to precise component location. 
Satisfactory operation of anti-tip mechanisms generally require great 
Precision in the installation of the anti-tip interactive components 
secured to the cabinet, and of the related actuating pins carried by the 
cabinet drawers, to make precise contact with the cabinet-mounted 
comPonents, in the opening or immobilization of respective ones of the 
drawers. 
SUMMARY OF THE INVENTION 
The present invention provides a mechanism for use with multi-drawer 
cabinets, the mechanism comprising a numbers of sets of components, one 
set for each drawer, attachable to the respective drawer slide, 
substantially independently of the cabinet structure. The mechanism may be 
provided in kit form for installation and use. 
The presently disclosed kit may be used as a retrofit for existing 
cabinets, or for new construction, or for repairs, being interchangeable. 
It is to be understood that "cabinets" include a wide variety of devices 
having multiple storage compartments. Office furniture including desks, 
credenzas, bookshelves and stands and other kinds of furniture are 
possible applications. Filing cabinets are also included. 
The kit components may be attached by way of brackets to existing drawer 
slides. However, it is preferred that drawer slide be included as a 
component of each set of the kit, including therewith provision for 
attachment of the relevant other components of the kit thereto. However, 
the means of attachment of the kit components to the drawer slides is not 
critical. 
It will be understood that a drawer slide, generally of the progressive, 
three component ball bearing type comprises a stiff, substantially 
precision engineered product of markedly greater strength, rigidity and 
precision than the pressed steel components that comprise the cabinet and 
drawers. Thus, the drawer slide provides a superior mount, both for the 
mounting bracket and its associated slide bar components, and for the 
actuating pin by way of its mounting bracket. The present invention thus 
provides a modular kit, for use in installed relation within a cabinet 
having at least one inwardly and outwardly slidable drawer, supported by a 
drawer slide having a stationary channel member and a movable slide member 
carried by the channel member, the kit comprising a component set having: 
support means securable to said channel member; slide bar assembly means 
slidably securable to the support means for substantially vertical 
displacement when installed; the slide bar assembly means including an 
upper bar assembly and a lower bar assembly adapted for installation in 
aligned relation; cam means carried by one said bar assembly operable 
between first and second positions; in the first position, said cam means 
being adapted to relatively displace said slide bar assemblies thereby 
forming a gap adjacent one end of said slide bar assemblies upon closing 
said corresponding drawer, in the second position, said cam means being 
adapted to relatively displace said slide bar assemblies thereby 
substantially filling said gap upon opening said drawer; means for 
limiting the maximum relative displacement of said slide bar assemblies to 
a distance substantially equal to said gap; and actuating means securable 
to the movable slide member and adapted to engage said cam means in said 
first and second positions, such that in said first position, if said 
slide bar assemblies are obstructed from filling said gap, opening of said 
drawer is prevented. 
The invention also provides a latching mechanism for a series of aligned 
storage compartments within a cabinet, each compartment being mounted on 
drawer support slides in slidable engagement with drawer slide stationary 
members supported by said cabinet, said mechanism comprising: a plurality 
of substantially vertically aligned slide bar assemblies each having slide 
bars connected to a corresponding drawer slide stationary member and 
slidable between opposed ends, one of the ends, with the compartments in a 
closed position, defining a gap between said end of the aligned slide bar 
assemblies and the cabinet; and an engagement means corresponding to each 
compartment, each engagement means being adapted to be carried by a 
corresponding drawer slide and adapted to bear on one of the slide bars, 
each engagement means being movable when the slide bars are slidable in 
the direction of the gap and being adapted to prevent opening of the 
corresponding compartment when movement of the engagement means is 
prevented, so that, while the slide bars are slidable in the direction of 
the gap, opening of a compartment causes the corresponding engagement 
means to move, thereby causing at least one of the slide bars to slide a 
distance substantially equal to the gap and to slide in the direction of 
the gap, and also causes the said corresponding engagement means to bridge 
the gap, thereby preventing sliding of the other slide bars and movement 
of the other engagement means, the engagement means when prevented from 
movement obstruct the opening of the other compartments, so that, when any 
compartment is open, the opening of other compartments is prevented. 
In one embodiment, the kit further includes a drawer slide, for 
installation within the cabinet, having means to facilitate attachment of 
other components of the device thereto at a predetermined longitudinal 
location along the slide, to facilitate vertical registry of one set of 
slide bars with the slide bars of vertically adjacent sets of slide bars. 
In a further embodiment the device components include biasing means, 
preferably a return spring for attachment to one of the slide bars to urge 
the slide bars together and away from the gap. 
A yet further embodiment may incorporate lock means installable in the 
cabinet and operable to immobilize the aggregate slide bar assembly of a 
series of kits or latching mechanism against individual separation between 
top and bottom bars of each set by actuation of the respective cam means. 
The device in accordance with the present invention may incorporate 
therewith a slide bar stop means, for attachment to a Portion of a cabinet 
in aligned relation with an adjacent bar of a plurality of slide bar 
assemblies thereby forming a gap between said stop means and the adjacent 
bar, to permit stacking of the bars in mutual inhibiting relation by 
operation of one of the drawers thereby causing the adjacent bar to fill 
the gap, or by the introduction of locking means to occupy the gap 
otherwise present between the stop means and the adjacent bar member with 
all the drawers closed. The kit may in this fashion be used to provide a 
combined anti-tip mechanism and locking means for a multiple drawer 
cabinet. 
Alternatively, inner surfaces of the cabinet may provide the required space 
limitation of the stacked bars for their required operation. 
It will be understood that the term "drawer" encompasses the usual box-like 
receptacle and other storage compartments, of differing proportions and 
construction, suited for use with the present invention. A drawer 
component, and cabinet may be made of any one or more of a wide variety of 
substantially rigid materials, including, metals, wood or wood laminates, 
plastics and many others. 
The present invention further provides a method of providing an anti-tip 
capability to a cabinet having a plurablity of drawers mounted for free, 
substantially unrestricted opening and closing motion including the steps 
of: securing in aligned relation along one side of said cabinet a 
plurality of slide bar assemblies to drawer slide stationary members at a 
predetermined location therealong; attaching movable cam means in abutting 
relation with a slide bar assembly for each of the related drawer slides; 
securing actuating means to a drawer support slide bar for each of the 
related drawer slides, in predetermined registry with said cam means of 
the slide bar assemblies, to control withdrawal movement of the actuating 
means and drawer support slide; and, providing limit means to limit 
expansion of the slide bar assemblies to a predetermined amount sufficient 
only to permit actuation of a single cam means by the related actuating 
means, for withdrawal of the associated selected drawer.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1, 2, and 3 a first embodiment assembly 10 of a single 
set of the modular kit comprises bracket 12 having a channel 14. Upper 
slide bar 20 and lower slide bar 22 may travel along the axis of channel 
14. Guide tabs 16, 18 are provided along or adjacent channel 14 to limit 
lateral displacement of upper slide bar 20 and lower slide bar 22. 
In this embodiment, cam means 24 are pivotally secured by pivot pin 26 to 
the lower slide bar 22, having the bracket 12 located between slide bar 22 
and cam means 24, with the pivot pin 26 slidably located in channel 14. 
Accordingly the cam means 24 is able to undergo rotational or 
translational movement provided no external restrictions exist. The pin 26 
serves also to secure slide bar 22 to the cam means 24 through the channel 
14 of bracket 12. 
The upper slide bar 20 has a cam follower portion 32 secured thereto by one 
or more pins or rivets slidably extending through the channel for vertical 
sliding movement in channel 14 as it follows the bearing surface of cam 
means 24. The edge portions of bracket 12 which define the channel 14 
extend in sandwiched relation between the upper slide bar 20 and the cam 
follower portion 32, to retain the cam follower portion in aligned 
registry with the actuating upper edges of cam means 24. The cam follower 
portion may be secured to the upper slide bar by a pin or rivet 5. Pin 5 
extends through channel 14 thereby permitting displacement of upper bar 20 
along the channel axis. It is readily understood that the terminal ends of 
channel 14 define the extent that the lower slide bar 22, and in turn, 
slide bar 20 may be vertically displaced relative to the bracket. It is 
also apparent that by carefully selecting the relative length of the 
channel 14 to be substantially equal to the distance displaced by the 
upper and lower slide bars upon opening of the corresponding drawer, a 
feature is thereby provided to limit the total displacement of the slide 
bars in that assembly, as well as the displacement of like slide bars 
present in other assemblies installed in combination therewith. Where a 
cam has been displaced vertically due to the rotation of some other cam, 
it can be appreciated that no further rotation or displacement will be 
allowed until the rotated cam is returned to the "closed" position. 
Alternately, it is possible to select channels of greater length if other 
stop means are provided to ensure that when installed in combination in 
aligned abutting relation, said slide bar assemblies will be permitted to 
separate a distance sufficient only to allow one corresponding drawer to 
open. When a series of slide bar assemblies have been combined to 
cooperate with a corresponding number of drawers, the distance to be 
bridged by a cam upon rotation from the closed position to the open 
position will be substantially equal to the displacement or separation of 
the bars. Similarly, when stacked in vertically aligned abutting relation, 
the distal moving end of combined slide bars will also be displaced an 
equivalent distance upon rotation of one cam. The space located at such 
distal end shall be referred to as a "gap". In the disclosed embodiment, 
the lower slide bar, cam means, upper slide bar and cam, follower means 
may be upwardly displaced along the channel by a vertically activated 
slide bar acting from below even though no rotation of the corresponding 
cam has been effected, provided no restrictive means have been activated 
to prevent such displacement. The lower terminal end of channel 14 defines 
the position of the sliding bars in the assembly when the corresponding 
drawer is in the closed position. The sliding bars in a first assembly 
will be upwardly displaced relative to that position upon opening of the 
corresponding drawer, in the first assembly, or upon opening of a drawer 
in an aligned assembly located below the first assembly. 
In a preferred embodiment shown in FIG. 4, sliding bars 20 and 22 are 
secured to retainers 33 and 35 by means of screws or rivets 60 and 62 
respectively. Other securement means may be employed which permit for 
efficient assembly of the bars to the other kit components. Although it is 
not essential to employ detachable bar components, it is preferable to do 
so to provide space saving advantages during shipping prior to 
installation. Similarly, where the bars are detachable, a wider range of 
applications may be provided for in each kit. Bars of differing lengths 
may be secured in each assembly, depending upon the distance to be spanned 
between adjacent abutting assemblies. Suitable lengths should be selected 
to ensure that adjacent slide bar assemblies are capable of abutting 
contact when installed for operation. In those applications where a kit 
will be used as a latching mechanism for individual securement of one 
drawer, the slide bar length will usually be selected to be sufficient to 
act in cooperation with a locking bar or plunger. The length will be 
selected such that in the closed position, said locking bar will abut 
against a slide bar so as to prevent opening of the corresponding drawer. 
Tension springs 37 are connected to the support bracket and retainer 33 in 
order to bias upper bar 20 to the "closed" position. It is understood that 
in most applications where two or more kits are used to form a latching 
mechanism, only the uppermost assembly of a series of abutting assemblies 
requires springs in order to provide this biasing action for all aligned 
assemblies. For example, upon opening of the lowermost drawer, the bar 20 
of such assembly would be displaced upwardly thereby engaging and 
displacing the adjacent abutting slide bar along with the bars of each of 
the assemblies located above. As the support brackets in each assembly are 
to be fixed against vertical displacement, and said slide bars in the 
closed position are all in abutting contact with adjacent slide bars, the 
springs in the uppermost assembly would be placed under load upon opening 
any such drawer. 
Referring to FIGS. 3, 4 and 5 the assembly 10 is shown in secured relation 
with a drawer slide assembly 34. The illustrated drawer slide assembly 34, 
of the progressive 3-channel type comprises a stationary slide channel 
member 36, a drawer support slide 38 having clips 39 to which one side of 
a drawer (not shown) is secured. An intermediate movable slide 40 connects 
movable slide 38 with slide channel member 36, for full extension of 
drawer slide 38. SupPort bracket 12 is secured to member 36 by means of 
pins or rivets 66 or other suitable means. 
Each kit is provided with an actuating pin 44 carried on a mounting bracket 
42. Together, each actuating pin and its corresponding cam means, 
cooperate to provide an engagement means to prevent opening of the 
corresponding drawer if the corresponding upper and lower slide bars have 
been restricted against separation. If no such restriction has been 
presented, the cam means and pin will engage upon withdrawl of the drawer, 
causing the sliding bars to separate thereby filling the gap. 
A bracket 42 secured to drawer slide 38 carries actuating pin 44 in 
laterally projecting relation to engage the surfaces 25 of cam means 24. 
The bracket may be secured to the slide in a number of ways known in the 
art, including, by means of rivets, screws, bolts, or welding. Pins or 
rivets 50 are shown in the present embodiment. The selected securement 
means will depend upon a number of factors including which tools are 
available or most desirable to the person installing the kit for 
operation. 
In a combined set of aligned assemblies, the sliding bars in a first 
assembly will be upwardly displaced relative to the closed position upon 
opening of the corresponding drawer. This will occur whether a drawer 
corresponding to the first assembly or a lower assembly is opened. 
The stationary slide channel member 36 is provided on the reverse face 
thereof with struck-out clip portions (not shown) to provide precise 
registry and secure attachment of channel member 36 with the structure of 
a cabinet, which does not form a part of the present invention. 
FIG. 4A shows a more preferred embodiment of the present invention. A 
mounting bracket 12' is secured to drawer slide bar 36' by means of pins, 
rivets or bolts 66'. Alternate securement means may be used. Bracket 12' 
defines a channel 14', one end of the channel terminating intermediate the 
top and bottom of the bracket. The other end of the channel extends 
outwardly to the outer edge of the top of the bracket to define a mouth or 
entrance to the channel. A retainer bar or other suitable means (not 
shown) may be secured adjacent the entrance to the channel to provide 
added security against misalignment or escape of members normally 
operating with the channel. Lower bar 22', situated on one side of bracket 
12' is secured to bottom bracket 35' on the other side of bracket 12' by 
means of lower bracket pin 62'. Lower bracket pin 62' travels within 
channel 14' upon upward displacement of the lower bar 22'. A rotatable cam 
24' is secured to a turning fork 24" by means of intermediately located 
rigid pin 26'. The cam 24' is carried on the bottom bracket, but the cam 
is not connected or otherwise secured to the lower bar assembly. It can be 
readily understood that each of the bar assemblies and the cam means 
including the cam and fork assembly may be slidably inserted into channel 
14' when assembling the mechanism. Cam 24' is positioned on the same side 
of bracket 12 as bottom bracket 35' and upper bracket 33'. Cam surface 70 
bears against the lower surface of upper bracket 33'. Similarly, cam 
surface 71 bears against the upper surface of the lower bracket 35'. 
Brackets 33', 35' and cam 24' on one side, with sliding bars 20', 22' and 
turning fork 24" on the other side effectively sandwich mounting bracket 
12' between them. It is understood that it is possible to mount the cam 
and turning fork on one side of the mounting bracket provided suitable 
means are included to permit proper operation of the cam means along the 
channel. Upper bracket 33' is secured to upper sliding bar 20' by means of 
upper bracket pin 5'. 
When a drawer is opened, the corresponding actuating pin 80 engages turning 
fork 24", rotating the fork to the open position. At the same time, cam 
24' is rotated to the open position, causing surface 27' to bear against 
the lower surface of the upper bracket 33' causing the upper bracket and 
in turn, the upper bar to be displaced upwardly. 
Referring to FIG. 6, a stacked series of slide bars for a three drawer 
arrangement is shown schematically, having the upper slide bars 20 and 
lower slide bars 22 in axially stacked relation. In fact, the stack 
effective height includes those contact portions, between respective cam 
means 24 and cam followers 32. However, those portions of stack height are 
represented pictorially by the junctures of upper slide bars 20 with lower 
slide bars 22, for each of the three illustrated kit sets. In this 
embodiment, limiting means or a fixed stop member 47 secured to the 
cabinet limits upward slide bar displacement. A stop member which is 
secured to or integral with the support bracket of the topmost sliding bar 
assembly maY also be Provided. Such a stop member could be used to 
restrict the topmost assembly and all assemblies below against upward 
displacement which could permit more than one drawer to be opened. In the 
preferred embodiment, the channel 14 in each assembly is of sufficient 
length to permit one way vertical displacement equivalent to the opening 
of one drawer only. The length of each channel in the preferred embodiment 
is restricted to prevent the opening of more than one drawer. It is 
understood that the channel may be of greater length provided suitable 
stop means are included to prevent excessive travel or displacement. 
Referring to FIG. 6 A, with each of the related drawers in a closed 
position and the cam means 24 undisturbed, bar stack clearance or gap "x" 
is available. As shown in FIG. 6 B, with the middle drawer withdrawn and 
the cam means 24 displaced to generate the clearance "G" between upper and 
lower slide bars, the gap "x" is effectively taken up. In this condition 
the middle drawer is free to slide in and out whereas the upper and lower 
drawers are locked closed. 
In FIG. 6C, with all of the drawers closed, the introduction of locking bar 
4C takes up the gap "X" sufficiently to preclude operations of any of the 
cam means 24, thus locking all three drawers. 
In order to use the presently disclosed kits 10, in the case where the 
original drawer slide assemblies are utilized, with the drawers removed 
from the cabinet the drawer slide assemblies 34 are removed from one side 
of the cabinet. The drawer slide assemblies 34 may be through-drilled, in 
the case of stationary channel member 36 and drawer support slide 38, 
generally without further disassembly, using positioning templates or 
equivalent, to receive screws (not shown) for attachment of brackets 12 
and 42, respectively, thereto. Alternate securement means may be used. 
With brackets 12 and 42 in place the upper slide bars 20 are assembled to 
the respective assemblies 10, by insertion in channel 14 of bracket 12 and 
the slide assemblies 34, carrying the kit components secured thereto are 
then reinstalled within the cabinet. As will be understood by those 
skilled in the art, where the cam and turning fork are carried by but are 
not attached to a sliding bar assembly, the cam and fork assembly may be 
inserted into the channel such that the cam will abut with the bar 
assemblies. 
Meanwhile, the cabinet, when necessary, has a stop member 47 installed. 
In cases where a lock is to be installed, the face of the cabinet is 
appropriately drilled to receive the lock set (not shown), for the 
insertion of lock bar 49, of which only a portion is shown, which is 
provided with a guide (not shown) adjacent the remote end seen in FIG. 6 
C. The lock bar is positioned such that upon locking the cabinet, the lock 
bar fills the gap "X" thereby preventing all drawers from opening. In 
other embodiments, a biased locking bar may be Provided which permits the 
lock bar to be activated even if one drawer is open. In such a case, the 
lock bar may be biased by spring means such that, upon closure of the one 
open drawer, the lock bar would enter into the gap thereby locking all 
drawers against opening. 
Reinstatement of the drawers completes the conversion, and after testing 
and any final adjustments, the cabinet is returned to service. 
Where conversion of a cabinet utilizes replacement drawer slide assemblies 
34, the original slide assemblies on the appropriate side of the cabinet 
are removed and the replacement slide assemblies 34, having the brackets 
12 assembled therewith, together with rods 20, 22 and cam means 24, are 
installed within one side of the cabinet. The rest of the process is as 
detailed. 
It will be evident that the subject kit may be used as a locking 
arrangement on a single drawer cabinet. 
Another embodiment is contemplated whereby a drawer slide assembly is 
provided with said kit components secured thereto. Detachable slide bars 
may be used where size considerations are important for shipping or 
handling purposes. 
A further contemplated embodiment envisages a plurality of cabinets in 
mutually superposed relation, wherein the cabinets may be out of vertical 
registry, in a front to back sense. The installed anti-tip device is 
located on a common axis therethrough. 
It will be understood to those skilled in the art that embodiments of the 
invention may be modified, and that such useful embodiments and 
modifications will be within the scope of the following claims.