Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to rack systems and
more particularly to a connection between a shelf
support element and a post of such a system.
Rack systems are used for storing many varied
products in warehouses, stockrooms and the like.
It is common nowadays for such systems to extend the
full height of a building and to be arranged in rows
providing space for unloaders to move between the rows.
The unloaders can remove stock from shelves in the system
and then transfer the stock to a central location for
processing.
There are a number of design criteria which
rack systems should meet. These criteria are becoming
more rigorous as the height of the rack systems is
increased. Safe-guards against collapse must be met by
;~ the design criteria so that a positive lock between
elements is essential. It is also preferable that the
system be designed to avoid accidental dislocation of
shelves from the posts supporting the shelves. Further,
economic considerations dictate that maximum rigidity
should be achieved using a minimum of materials and a
minimum of assembly operations.
Present rack systems generally use simple
hook arrangements to permit elements of a shelf to be
hooked onto a post. In many instances the elements can
be dislocated accidentally and are therefore not entirely
acceptable. Further, it is common to perforate the posts
for receiving the hook elements and the perforations are
commonly placed on the front of the post. This is the
portion of the post which receives the most stress caused
by bending forces and consequently the cross-section of
metal used must be increased to compensate for the
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weakness caused by the peforations.
In one aspect, the invention provides a rack
system having a positive yet releasable lock between posts
and shelf support elements to thereby create a relatively
strong and stable rack system.
In another aspect, the invention provides a
combination of a post and an end connector for use in a
rack system to support shelves and the like. The posts
have first and second side ribs extending longitudinally
and centre portions extend between the side ribs. Each
centre portion defines longitudinally spaced slots and the
side ribs are disposed symmetrically to either side of
the centre portions. Each side rib includes an outer
portion lying generally perpendicularly to a plane
containing the centre portion, a front portion lying
generally parallel to the centre portion, and a side
portion extending from the front portion to the centre
portion. The end connector has a channel shape adapted
to fit snugly over a side rib of one of the posts. The
channel shape is defined by first and second side portions
and a front portion extending between these side portions
and the end connector further comprises first and second
coupling elements extending rearwardly from the second
portion for engagement in said slots. Each of the coupling
elements has a cantilever portion and a downward projection
dependent from an end of the cantilever portion and
defines a rearward face inclined downwardly and rearwardly
for engagement with a rearward side of the centre portion
of the post after engaging the coupling element in the
post. Consequently a downward force on the end connector
will result in a wedging action as the rearward faces of
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coupling elements ride on the centre portion thereby '
drawing the end connector into firm and snug engagement
with the corresponding side rib of the post.
These and other aspects of the invention will
be better understood with reference to the drawings, in
which:
Fig. 1 is a perspective view of a section of
a rack system incorporating the invention;
Fig. 2 is an exploded perspective view of a
portion of the rack system and illustrating an end
connector about to be engaged in a post;
Figs. 3 and 4 are sectional side views
illustrating the assembly of the end connector and post
shown in Fig. 2;
Figs. 5 and 6 are sectional plan views which
- also illustrate the assembly of the'parts shown in Fig.
- 2;
Fig. 7 is a view similar to Fig. 2 showing
alternative embodiments of the parts shown in Fig. 2;
and
Fig. 8 is a view similar to Fig. 6 showing a
further embodiment of the post.
Reference is first made to Fig. 1 in which a
rack system is identified generally by the numeral 20.
The system consists of a plurality of vertically orientated
support frames of which support frames 22, 22' and 22"
are typical. The frames are spaced apart sufficiently to
receive pairs of shelf support elements such as elements
24a, 24a'; 24b, 24b'; 24c, 24c', 24d, 24d'. The numbered
support elements support shelves 26a, 26b, 26c, and a
further shelf between elements 24d and 24d' which is not
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seen in this figure.
Support frame 22 is typical of all the support
frames and will be described in more detail. Parts of
frames 22' and 22" which correspond to the parts described
with reference to frame 22 will be identified using
corresponding prime and double prime numerals. Support
frame 22 consis~ts of-a pair of upright posts 28, 28a,
which are of similar construction and have corresponding
parts facing one another. The posts are maintained in
parallel spaced relationship by respective horizontal top
and bottom braces 30, 32 and an inclined cross brace 34.
The posts also have respective foot plates 36, 36a and
corresponding head plates 38, 38a. The shelf support
element 24a is typical of the other shelf support elements
previously lntroduced. This element includes a stringer
40a extending between a pair of opposite-handed end
connectors 42a which are releasably connected to the
respective posts 28 and 28' as will be described more
fully with reference to subsequent figures. Similar
stringers and end connectors are used in the structure of
the other shelf support elements and ~re indicated by
corresponding numerals using primes and suffices to
differentiate the parts from one another.
As seen in Fig. 1, the shelf 26a is supported by
the shelf support element 24a which is assembled on the
post 28. Detail of this exemplary connection is shown
in Fig. 2 and reference is now made to this figure to
describe the interconnection between support elements
and posts generally, with particular reference to the
element 24a and post 28.
As seen in Fig. 2, the post 28 is symmetrical
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about a longitudinal axis and is roll formed to define
a pair of parallel outer portions 44, 46 dependent from
coplanar front portions 48, 50. In turn, the portions
48, 50 are dependent from converging side portions
54, 56 which extend from inner extremities of the front
portions 48, 50. The portions 44, 48 and 54 combine to
define a first longitudinally extending rib 49, and a
second such rib 51 is defined by portions 46, 50 and 56.
The side portions 54, 56 depend from a
centre portion 58 which is parallel to the front portions
48, 50 and spaced from these portions by a distance equal
to about half of the transverse extent of one of the
similar outer portions 44, 46. The cross-section of
the post 28 is completed by respective rear flanges 60,
62 which are dependent from portions 44, 46 and lie in
parallel arrangement with the front portions 48, 50.
Inwardly facing extremities of these flanges provide
support for receiving and welding the braces 30, 32 and 34
(Fig. 1).
After roll forming, the post 22 is punched to
define pairs of rectangular slots 64 which are arranged
at regular intervals along the length of thè post 28 for
interconnection with the end connector 42a as will be
described.
As seen in Fig. 2, the stringer 40a is welded
to the end connector 42a adjacent an upper extremity of
the connector. The stringer 40a is roll formed into a
generally L-shaped cross-section for providing a step
66 (shown in ghost outline) which supports a portion of
the shelf 26a. The end connector 42a extends downwards
from the horizontal stringer 40a and includes a first
portion 68 to which the stringer 40a is attached. The
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portion 68 lies at right angles to the stringer 48 and
extends from a front portion 70 which is generally
perpendicular to the portion 68 and from which a second
portion 72 depends. This last portion diverges rearwardly
with respect to the first portion 68. The angle of
divergence and the proportions of the connector 42a are
such that a channel is formed which will fit snugly over
rib 49 of the post 28 with the respective first and second
portions 68, 72 in face-to-face engagement with outer
portion 44 and side portion 54 of the post 28. This will
be more fully explained with reference to Figs. 5 and 6.
The end connector 42a also includes a first
coupling element 74 dependent rearwardly from the second
portion 72 and coplanar therewith. Similarly, a pair of
second coupling elements 76, 76a depend from the portion
72 for combining with the element 74 to attach the connector
42a to the post 28. This connection will subsequently be
more fully explained with reference to Figs. 3 and 4.
The first coupling element 74 consists of a
cantilever portion 78 which terminates in a downward
projection 80 and an upward projection 82. A forward or
outer face 84 of the projection 80 extends downwardly and
rearwardly for use in a wedging action as will be
described with reference to Figs. 3 and 4. The second
coupling elements 76, 76a are similar in all respects
to the first coupling element 74 with the exception that
the upward projection 82 is omitted.
Reference is now made to Fig. 3 to better
describe the interconnection between the end connector
; 30 42a and the post 28.
The first coupling element 74 and the pair of
second coupling elements 76, 76a are spaced from one another
by a distance equal to the corresponding spacing between
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slots 64 in the post 28. The end connector 42a will be
engaged in the post 28 at the same time as the other end
connector 42a (Fig. 1) is engaged in the post 36a. The
shelf support element 24a is tipped into the position
shown in Fig. 3 so that the upward projection 82 of the
element 74 can be entered into one of the slots 64. By
engaging an upward extremity of the cantilever portion 78
of element 74 against an upper extremity of the slot, the
shelf support element can then be rotated downwardly towards
the post 28 to enter the second coupling elements 75, 76a
into the pair of openings immediately below the opening
containing the first coupling element 74. The proportions
of the elements 74, 76 and 76a are such that they will
pass through the openings 64 with adequate clearance.
Shelf support element 24a is then allowed to move downwardly
towards the position shown in Fig. 4.
After the coupling elements 74, 76 and 76a are
engaged in slots 64 of the post, the end connector 42a
is initially in the position shown in Fig. 5. As the
downward movement of the end connector commences, the
rearward face 84 of the downward projection 80 engages
the centre portion 58 below the corresponding slot and
similar faces on the second coupling elements 76, 76a
also engage the centre portion 58. Consequently, because
of the angle of these faces a downward force will create
a component which draws the end connector 42a into firm
engagement with the post 28. As seen in Fig. 4 the
wedging action has been completed before the cantilever
portions of the coupling elements meet the bottom extremities
of the respective slots containing these elements.
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As illustrated in Fig. 6, the downward movement
which results in drawing the end connector 42a into firm
engagement with the post 28a is limited by the engagement
of the diverging first and second portions 68, 72 of the
end connector 42a with the corresponding outer portion
44 and side portion 54 of the post 28. Here again there
is a wedging action which results in firm engagement
between these parts and any further load on the end
connector 42a will simply result in firmer engagement
between this connector and the post 28.
Returning to Fig. 3, the upward projection 82
of the first coupling element 74 is used initially to
engage the end connector 42a in the post 28 as described.
However,after assembly, in the event that the shelf
supporting element 24a is dislodged upwardly by a fork
lift truck or the like, then the upward projection 82
will prevent the end connector 42a from falling off
the post 28. Once the upward force is removed the end
will drop downwardly and reinstall itself on the post
28. As soon as the shelf is loaded the engagement will
be enhanced on the post 28.
To assemble the structure shown in Fig. 1, the
support frames 22, 22' etc., would be prefabricated
according to the depth of shelf which is to be used. Once
assembled, the frames are positioned and built up with
the shelf support elements 42a, 42a' etc., before bolting
the frames to the floor and ceiling using the foot plates
36, 36a etc., and head plates 38, 38a etc. This is
because the spacing between the frames is critical and
consequently it is easier to place the bolts after assembly
than it would be to attempt to assemble the structure
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after bolting the frames individually to the floor.
Of course, in some instances it will not be necessary to
use the head plates and possibly not the foot plates al-
though these latter plates would normally be used.
With the frame 22 in position and the frame 22'
located as near as possible in its position, the shelf
supporting elements 24a, 24a' and 24b, 24b' are engaged
in position where shelves are to be located. It will be
evident that because both ends of a shelf support element
are engaged simultaneously, the openings (such as open-
ings 64) must be sufficiently wide to allow the extreme
ends of the coupling elements to pass into the openings.
These elements are inclined due to the divergence between
the first and second portions of the end connectors so
that this clearance must be provided. Alternatively the
shape of the coupling elements or second positions could
be changed to facilitate assembly in any suitable manner.
After assembly of the shelf support elements,
the frames 22 and 22' can be bolted in position and the
operation repeated to locate and install the frame22".
After installation of the frame, the heights of the shelves
can be changed by removing the shelves and removing the
corresponding shelf support elements before relocating
these elements at a different position on the correspond-
ing posts.
Reference is now made of Fig. 7 which illustrates
an alternative embodiment of post and end connector. In
this embodiment, a post 86 is somewhat similar in shape
to the post 28 but differs in that the centre portion 58
of post 28 is wider than a corresponding centre portion
88 of the post 86. In the Fig. 7 embodiment the centre
portion 88 is perforated by a series of slots 90 each of
which is sufficiently wide to receive an end connector
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92 (which is similar to end connector 42a) as well as a
corresponding end connector of a further shelf support-
ing element. For instance, if the embodiment shown in
Fig. 7 were used in Fig. 1, where the end connectors 42a
and 42c meet the post 28', then the end connectors 42a,
42c would be engaged in the same slots in the post.
The post 86 has advantages over the post 28
in that it requires less material and there are half as
many slots to be punched. However, some rigidity is lost
due to the reduced cross-section and it would be a mat-
ter of preference which of the two embodiments of the
post are to be used in a particular installation.
Fig. 7 also illustrates a stringer 94 made of
the same cross-section as the post 86. The shelf is
supported positively between the inwardly facing flanges
which correspond to the flanges 60, 62 shown in Fig. 2
on post 28.
Also, the end connector 92 has only two coup-
ling elements for engagement in slots 90. In general
the number of these elements is a matter of preference.
However, larger loads will require more elements to spread
thebearing load over a greater surface area.
Reference is now made to Fig. 8 which illus-
trates a further embodiment of a post and an end connec-
tor. In this embodiment the numerals for these parts
which correspond to parts described with reference to
Fig. 2 will be raised by one hundred, i.e. 140a will
correspond with 40a etc. It will be seen that this em-
bodiment differs from that shown in Fig. 2 in that the
portions 168 and 172 of the end connector 142a are paral-
lel and outer portion 144 and side portion 154 of the
post 128 are also parallel. In this embodiment these
parallel parts slide closely over one another on assembly
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and the wedging action of the coupling elements brings
the front portion 170 into firm face-to-face engagement
with the front portion 148 of the post 128.
There are a number of features in the construc-
tion of the parts of the rack system 20 which result in
the advantages for this structure over prior art struc-
tures. The wedging action created by the rearward face
84 of the first coupling element 74 and the corresponding
faces on the coupling elements 76, 76a combine with the
wedging action as the end connector 42a engages the outer
portion 44 and side portion 54 of the post 28 results in
a positive lock which retains the parts in their relative
positions.
A further feature is that the perforations
creating the slots 64 (Fig. 2) and the slots 90 (Fig. 7)
lie generally at the neutral axis of the posts 28, 86.
! Consequently the perforations have little effect on the
strength of the post because of any bending situation the
stress at the neutral axis is minimal. The metal at the
neutral axis is therefore available to carry the load of
the shelf in vertical compression so that the maximum
strength is achieved in a rolled section of moderate
wall thickness.
A further advantage of the structure is that
because the cross-section of the posts allows the braces
30, 32, and 34 (Fig. 1) to be inserted between the flanges
60, 62 (Fig. 2) and welded in place, the braces do not
interfere with the shelf space.
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