Note: Descriptions are shown in the official language in which they were submitted.
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KNOCK-DOWN SHELF UNIT
Field of the Invention
This invention relates in general to shelving units,
and more particularly to a secure knock-down utility
shelving system which may be readily as~sembled and
disassembled by a user.
Backq~ound of the Invention
It is known in the prior art to provide knock~down
shelving units which may be as3embled and disassembled
for ease o~ transportation. Such units are often used in
warehouses and storage rooms and are ~abricated from
sheet metal which may be roll ~ormed, stamped and cut to
the desirPd shape for assembly. These units are
typically pr~vided with four vertical cvrner posts and a
plurality of horizontal mambers. The corner posts are
often provided with a plurality of apartures for
receiving screws or bolts to connect the horizont~l
members thereto at user selected heights.
For example, Canadian Patent 1,256,069 (Hirsh
Company) discloses a shelving assembly having a plurality
of generally horizontal shelves which are connected to
four support columns or posts by conventional bolts or
nuts. Sp~ci~ically, each shelf is provided with a flange
which defines, at its corners, one or more holes for
receiving a bolt or screw which is then inserted through
a selected hole or aperture in the vertical column or
post.
One disadvantage of the prior art design disclosed
in the Hirsh Patent is that there are a multiplicity of
components required ~or assembly, includin~ the
a~orementioned nuts and bolts, as well as pliers and
screwdriver~, etc. Furthermore, it is possible for the
nuts and bolts to become loosened over time, thereby
resulting in potential instability of the ~helving
assembly.
According to another prior art techniqu~, th~
horizontal members are connected to the vertical posts by
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means of rivets. The rivets are inserted in vertically
arranged slots in the vertical posts. In an e~fort to
provide a secure connection, the distance from the side
edge (i.e. vertical face) of the vertical post o the
side edge of the slot is made ~lightly di~rence than
the distance from the side ~dge (i.e. vertical edge) of
the horizontal member to the neck of the rivet such that
there is effectively no clearance between he rivet and
the slot. Therefore, in order to install the rivet into
the slot, the rivet must be hammered into place by
hammering down on the horizontal member so as to distort
the metal forming the side edge of the slot.
This latter prior art technique also suf~ers from
the disadvantage that the shelving unit is difficult to
assemble. Furthermore, the connection of the rivet and
~lot edge is in the form of 2 single point connection
which may become loosened with time as with the prior art
Hirsh unit, thereby resulting in potential instability of
the shelving unit.
Summary of the Invention
According to the present invention, a knock-down
shelving unit is provided which is easy to assemble, has
few assembly components, and is characterized by an
interference fit between the horizontal memberæ and
vertical posts resulting in extremely stable
construction.
In particular, the knock-down shelving unit of the
pr~ent invention comprises a plurality o~ vertical posts
each in~luding a frontal vertical ~ace and a side
vertical face perpendicular thereto. A plurality of
horizontal members are provided each including a frontal
face and a vertical edge at each opposite end thereof.
Attachment means are provided for connecting the
horizontal members to the v~rtical posts, the attachment
means comprising at least one first portion in one of
either th~ ~rontal vertical fac~ of the vertical po~ka or
the frontal v~rtical face of the horizontal members, and
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at least one second portion adapted to extend from the
other one of the frontal vertical face of the vertical
posts or the frontal vertical face o~ the horizontal
members, wherein the at least one first portion comprises
a generally key hole shaped aperture having a hole and
slot extending therefrom at a predetermined acute angle
to vertical, and the at least one second portion
comprises a neck and a head portion extending from the
neck, the head portion being cooperatively shaped ~or
insertion throuqh the hole and the neck being
cooperatlvely shaped to slide within the 510t, whereby
upon inserting the neck portion through the hole the neck
slides within the slot at the aforementioned
predetermined acute angle until the vertical edge of the
horizontal member engages the side vertical ~ace nf the
vertical post and further sliding o~ the neck within the
slot results in an interference ~it therebetween.
Brie~ DescriPtion of the Drawinqs
A detailed descriptiQn o~ the invention is provided
below with reference to the ~ollowing drawings, in which:
Figure 1 is a perspective view of the knock-down
shelving unit of the present invention;
Fiyure 2 is an enlarged, fragmentary side elevakion
Yiew of a vertical post, horizontal member and attachment
means therebetween, in accordance with the preferred
embodiment;
Figure 3 iæ a cross sectional view through III-III
in Figure 2; ,
Figure 4 is an enlarged, fragmentary, side elevation
view of a horizontal member and vertical post in
accordance with an alternative embodiment of the
invention; and
Figure 5 is a perspective view o~ attachment means
for use with the preferred embodiment of Figure 4.
Detailed Desc~i~tion of the Preferred Embodiment
Turning to Figure l, an assembled shelving unit 1 is
shown comprising ~our vertical posts 3 each having a
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frontal vertical face 2 and side vertical face 4, and to
which a plurality of horizontal memhers ~ are attached.
The horizontal members 5 are each characterized by a
frontal vertical face 6 and horizontal ledqes 8 ~shown in
5 detail with reference to Figures ~-5). Shelf units 7
rest on the horizontal members 5O Cross bracing ~embers
(not shown) may be provided for additional ~tability.
However, the stable nature of the shelving unit
constructed in accordance with the pre#ent invention
substantially alleviates t~e requirement for cross
bracing.
As shown in greater detail with ref~rence to ~igures
2 and 3, the frontal face 2 of each vertical post 3 is
provided with a plurality o~ key hole shaped apertures 11
each comprising a generally circular hole 13 and a slot
15 oriented at an acute angle. This angle is preferably
in the range of from 8 to 30, and more preferably is 10
from vertical.
Each horizontal member 5 comprises at least one
attachment connector 17 which, according to the pre~erred
embodiment, comprisQs a neck 19 and head portion 21.
Preferably, there are two attachment connectors 17.
Preferably, the neck 19 and head portion 21 are in the
form of a rivet which may be intalled in the hori~ontal
member 5 during fabrication thereof. Alternatively, the
neck 19 and head portion m~y be stamped or punched ~rom
the sheet metal horizontal member 5 so as to be integral
therewith.
In operation, the attachment means 17 are inserted
through respective key hole apertures 11 such that the
head portion 21 passes through the circular hole 13 and
the vertical edge 23 of the horizontal member 5 rests
against the inside surface of the vertical side face 4 o~
the vertical post 3. Downward pressure is then applied
to the horizontal member 5 such that the neck 19 slides
downwardly within slot 15. Since the slot ~5 is disposed
at an angle, the clearance between the neck 19 and the
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edge of the slot 15 diminishes such that additional
downward pressure results in an interface fit between
horizontal member 5 and vertical post 3. The
interference fit between horizontal member 5 and vertical
post 3 extends over the full length of the slot 15 rather
than forming a single point oonnection as in the prior
art, thereby resulting in a firm interconnection.
However, the shelving unit assembled in accordance with
the preferxed embodiment o~ Figures 2 and 3 may
nonetheless be disassembled by applying upward ~orce to
the horizontal member 5 for dislodging the horiæontal
member from the vertical post 3.
As discussed above, the angle of inclination of the
slot 15 may vary within a preferred range of acute angle~
(although a 10 angle of inclination has been determined
through experimentation to be optimum). As the angle of
inclination increases, the interface fit between the slot
15 and neck 19 becomes tighter but a larger tolerance is
required. Conversely, as the angle o~ inclination of
slot 15 is made less, the tightness of the interface fit
reduces and the tolerance requirements are relaxed.
According to a successful prototype, the head
portion 21 is in the form of a circular disk having a
diameter of approximately 7/16" and a thickness o~
approximately .005". The neck 19 is in the form of a
circular cylinder having a diameter of approximately
0.~40", and the length of the neck 19 from the base to
the head portion 21 is approximately 0.08". The hole 13
is preferably circular and has a diameter of
approximately 0.0500", and the slot 15 is generally
oblong and ha~ a width of approximately 0.250" and a
length of approximately 0.500" extending ~rom the centre
of focus of the oblong to the center o~ the hole 13.
However, other dimensions of these components are
possible.
Turning to the alternative embodiment shown in
Figures 4 and 5, the construction of vertical post 3' is
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substantially the same as shown in Figure 2 with the
exception that the slot 15' is o~ generally oblong shape
(i.e. with a semi circular end portion)~ ~s an
alternative to the rivet attachment means 17 of Figures 2
and 3, in the embodiment of Figures 4 and 5 an attachment
means 17' is provided which i5 separable from the
vertical post 3' and horixontal ~ember 5'. In
particular, the attachment means 17' o~ Figure 5 is ~hown
comprising a first head portion 21', a neck 1~' and
further head portion 25, resulting in an ov~rall shape
generally ~imilar to a yo-yo which is a adapted tv b~
inserted through key hole apertures 11' in the vertical
post 3' and through ~urther key hole 27 in the horizontal
member 5'. The neck 19' slides within slots 15' and 29
in response to downward pressure on the horizontal member
5'. As with the embodiment of Figures 2 and 3, movement
of the neck 19' in the ~lots results in vertical sdge 23'
wedging against the vertical face 4' of vertical post 3'.
When installed, the head portion 21' projects ~rom
the apertures 11' and 27 adjacent vertical post 3' while
the head portion 25 projects from the apertures 11' and
27 adjacent the horizontal member 5', thereby retaining
the attachment means 17' within the two sets of apertures
11' and 27.
According to a successful prototyp~ of the
alternative embodiment, the head portions 21 and 25 are
in the form of circular disks one having a diameter of
approximately 7/16" and the other slightly greater than
tha diameter of the circular hole 13', and a thickness o~
approximately .005". The neck 19/ is in the form o~ a
circular cylinder ha~ing a diameter of approximately
.240", and the distance of the neck 19' separating heafl
portions 21 and 25 is approximately 0.80". By making one
o~ the head portions larger than the hole 13', the
enlarged head portion is prevented from passing through
the hole 13' a~ter the o~her head portion ha~ already
been inserted.
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Furthermore, according to the alternative embodiment
of Figure 4, the hole 13' is preferably circular and has
a diameter o~ approximately 0.500", and the slot 15' is
generally oblong and has a width o approximately 0.250"
and a length of approximately .500" ext~nding from the
centre of focus of the oblong to the centre of the hole
13~o
According to the successful prototype, the vertical
post 3 ~and vertical post 3') and the horizontal member 5
(and alternative horizontal member 5') ar4 ~abricated
from sheet metal having a thickness of approximately
O . 036!' .
Other embodiments and variations are possible within
the sphere and scope o~ the claims appended hereto.
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