A boltless sheet metal cabinet assembly having a top wall, a bottom wall, a back wall, and opposed side walls, a flange on the back longitudinal edge of each side wall, that forms a U-configuration, a flange on each of the side edges of said back wall that forms a U-configuration, the flanges on the back wall and the flanges of the side walls being adapted to interlock with each other, the front longitudinal edge of each side wall being formed with a channel, rigidifying top and bottom bars having stab connectors at each of their ends for entry into the channel of one of the side walls whereby to extend between the side walls and space them apart, the top wall having downwardly extending flanges, the flange along the front edge of the top wall adapted to snap over the lower portion of the rigidifying top bar, the flange along the back edge of the top wall having a U-configuration, the upper edge of the top wall having a flange that forms a U-configuration that is adapted to interlock with the flange on the back edge of the top wall, each of the back wall and side walls having an inwardly directed channel at their lower edges, the bottom wall having flanges along its back and side edges adapted to drop into said channels of the back and side walls, and the bottom wall having a flange at its front edge to embrace the bottom rigidifying bar.

This invention relates to an assembly for a sheet metal cupboard or cabinet 
that can be assembled from a lay-flat, knock-down condition to an erected 
position without the use of bolts. 
Assemblies for sheet metal cupboards and the like that can be erected from 
a knock-down to a set-up position are popular. The component parts of the 
assembly of the nature with which this invention is concerned are made 
from a relatively light guage sheet metal. The consumer buys the assembly 
in a cardboard container in the lay-flat condition, takes it home and 
assembles it. The assembly operation is, of necessity, simple because it 
must be something that can be handled by the ordinary householder, who is 
not a skilled fitter. 
The use of these assemblies has, however, given rise to problems that are 
of long standing. In the past the assemblies must be secured in position 
by bolts. These bolts require screw drivers and, in some cases, wrenches 
for completion. Many householders do not have an appropriately sized screw 
driver or wrench. This is obviously an inconveniene. Many others find it 
difficult to manipulate nuts and bolts in the assembly of a simple 
cupboard. In many instances the assembly of these cupboards is attempted 
by persons of the lowest mechanical skill. 
There is also the problem of providing sufficient nuts and bolts to do the 
job and the problem of nuts and bolts becoming lost. These are problems of 
stock keeping and of complaints made to retailers because of deficiencies 
of the shipment. 
This invention overcomes all of these disadvantages that arise from the 
inclusion of nuts and bolts in the cupboard assembly. With this invention 
the component parts have been fashioned to interlock and maintain 
themselves in assembled position without the use of nuts and bolts. The 
general arrangement of the parts is similar to that of the prior art, but 
the parts have been designed such that they interact with each other to 
maintain the assembly rigid without the use of bolts and this is a very 
substantial advance in the art of providing simple knock-down cupboard 
assemblies. 
A boltless cupboard or cabinet assembly according to this invention 
comprises a boltless sheet metal cupboard having a top wall, a bottom 
wall, a back wall, and opposed side walls, the back wall and the side 
walls being formed along their adjoining edges to telescope together in a 
direction longitudinally of their edges, a rigidifying top bar to extend 
between the side walls of their upper extremities, said top bar and said 
side walls being formed to telescope together, rigidifying bottom bar to 
extend between the side walls at their lower extremities, said bottom bar 
and said side walls being formed to telescope together, said top wall 
having a downwardly extending front flange adopted to overlie the front 
face of said top rigidifying bar and an inwardly projecting locking flange 
at the lower edge of said front flange adapted to engage the marginal area 
of the underside of said top rigidifying bars in use, said bottom wall 
having a downwardly extending front flange adpted to overlie the front 
face of said bottom rigidifying bar and an inwardly projecting locking 
flange at the lower edge of said front flange adapted to engage the 
marginal area of the underside of said bottom rigidifying bar in use, the 
side walls and back wall being formed along their adjoining edges to the 
bottom wall with a channel adapted to receive the adjoining edge of the 
bottom wall in nesting relation. The invention will be clearly understood 
after reference to the following detailed specification read in 
conjunction with the drawings.

In the drawings the numeral 10 generally refers to a cupboard constructed 
in accordance with the present invention. The cupboard has been assembled 
without the use of bolts of any kind. This is a very substantial advantage 
for a cupboard of this general class which must be manufactured for 
shipping and storage in a knock-down form wherein each of the walls and 
shelves are packed in stacked relation within a carboard container. It is 
practice to ship these items to retail merchants who sell them to 
consumers. The consumer takes delivery of the compact flat package and 
erects th cupboard himself. 
It will be apparent that it is of importance with such articles that the 
component parts should be easy to assemble and preferably without the use 
of bolts because bolts tend to become misplaced. They also require tools 
for assembly. Many householders do not have a good selection of tools 
available and, in the case where a screwdriver is required, there is often 
a necessity to acquire a special screwdriver for the particular type of 
bolt supplied. 
The cupboard illustrated has a top wall 12, a bottom wall 14, a back wall 
16 and opposed side walls 18 and 20. A door 22 is hinged to a channel 
formation on an edge of side wall 20. 
As noted above, the top wall, bottom wall, back walls and door are supplied 
in knock-down form. FIGS. 2 to 5 illustrate the manner of assembling these 
parts. 
The back wall 16 is laid flat on a floor with the shelf hooks 25, to be 
referred later, facing upwardly. The side edges of the back wall each have 
a longitudinally extending hem which assumes a U-formation as at 24 in 
FIG. 2a. The back upright edges of the side walls 18 and 20 each have a 
flange that extends at right angles therefrom and that is also formed with 
a U-shaped hem as at 26. The U-shaped hems on the back wall and the side 
walls are adapted to interlock as the side walls are slid longitudinally 
of the back wall in right angled relationship as indicated in FIG. 2. 
The front edges of each of the side walls is formed with a channel as at 27 
(FIG. 2b) to accommodate the stab connectors 28 of the top and bottom 
rigidifying bars 30. 
The rigidifying bars generally indicated by the numeral 30 comprise a 
U-shaped horizontal sheet metal channel 32 to which is welded a stab 
contact generally indicated by the numeral 28. Stab contact 28 has a 
U-shaped form at its inner portion with a bottom 32 and side walls 34 and 
36. The U-shaped channel forms a channel that telescopes within the 
U-shaped channel 27 of the side walls. The free end portion of the stab 
has been cut away as at 38 to facilitate alignment. The inside wall of 
channel 27 is also cut away adjacent each end of the side walls to permit 
the laterally extending channel 32 to sit flush with the top and bottom of 
the cabinet as illustrated in FIG. 3 when the stabs of the rigidifying 
bars are firmly in place. 
FIG. 2 generally illustrates the direction of insertion of the stabs of the 
rigidifying bars into the channels of the side walls and FIG. 3 
illustrates the side walls and rigidifying bars finally in place. 
Thus, the initial steps of installation as indicated in FIG. 2 consist of 
sliding the side walls into contcat with the back wall and inserting the 
stabs of the rigidifying cross bars into the channels of the side walls 
wherein they are a snug telescoping fit. 
The top wall 12 has downwardly depending flanges that are adapted to 
overhang the vertical walls of the cupboard at the upper marginal 
portions. The sides of the top wall are slipped over the end of the body 
as indicated in FIGS. 3, 5 and 6. It will be noted that the front flange 
of the top wall 12 has an inwardly directed locking flange 39 along its 
front edge. This locking flange snaps over the lower edge of the 
rigidifying bar 30 to maintain the top wall in assembled position with 
respect to the body. 
It will also be noted that the back wall of the top 12 has a seam 40 on its 
downwardly flange. The upper edge of the back wall 16 also has a seam as 
at 42 along its edge for cooperation with the seam 40. FIGS. 3 and 5 show 
the initial stages of placement of the top wall. As the top wall is 
rotated in the direction of the arrow the flange 39 snaps over the bar 30 
as in FIG. 6. 
After the top wall 12 has been snapped into position as described, the back 
wall 16 is slid towards the top wall as indicated in FIG. 5. In this 
position the open edges of th seams 40 and 42 are facing each other. The 
back wall 16 is then slid downwardly to cause the seams 40 and 42 to 
interlock with each other. This achieves a securement of the back wall to 
the top wall along their respective meeting edges. 
It will be noted that the bottom edges of the side wall 18, back wall 16 
and side wall 20 are each formed with an internally directed channel. 
These channels are adapted to receive the downwardly directed flanges 44, 
46 and 48 respectively of the bottom wall 14. Downwardly directed flanges 
44, 46 and 48 have an in-turned edge and are a comfortable fit within 
their respective channels on the side walls to achieve a good rigidifying 
function. 
The front wall of the bottom 14 is formed with an internally directed 
locking flange 50 that springs over the lower eege of the bottom 
rigidifying bar 30 as the bottom wall is pressed into position. The bottom 
wall is pressed into position from the inside of the cabinet as 
illustrated in FIG. 3. 
All parts are made from a sheet metal which has a certain amount of 
resilience to permit the springing action of the flanges and the unit, 
when assembled as illustrated in FIG. 1, is rigid. The various flanges 
that fit within each other are a comfortable fit that provides a support 
to maintain the cupboard erect and square. 
The door is simply attached by means of a simple hinge that has previously 
been assembled to the door and the edge of side wall 20. 
The channels down the front edges of the side walls are notched as at 54 to 
receive the front edge of shelving units 56 which are inserted from the 
top as indicated in FIG. 1 and rotated rearwardly to sit on the lugs 25 in 
the back wall. 
The back wall 16 is locked against displacement by manipulation of the lugs 
58 in an inward direction to engage with the upper edge of the U-shaped 
formation 42 on the back wall 16 whereby to prevent it from disengagement 
with the cooperative seam 40 of the top wall as illustrated in FIG. 6. 
The basic structure of the unit is not new. For example, units of this 
general type and having cross support bars like the support bars 30 but 
which are held together by bolts are old. The novelty in this invention is 
the construction of the parts so that they can be slid and pushed together 
in a way that they will maintain their erect position without the need of 
any bolts. It is the combination of features that contribute to the 
boltless construction and the features that are new and thought to 
contribute to the end result. The sliding cooperation of the side walls 
and back wall at their longitudinal edges, the spring securement of the 
top wall and bottom wall with the side walls through the expedient of the 
spring flanges 39 and 50 and the interlocking of the top wall to the back 
wall along its upper edge by displaceable lugs 58. These features combine 
to eliminate the requirement for bolts in assemblies of this kind. 
Embodiments of the invention other than the specific one illustrated will 
be apparent to those skilled in the art and it is not the intention that 
the invention should be limited by the specific embodiment illustrated.