Note: Descriptions are shown in the official language in which they were submitted.
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Back frame
Field of the invention
The present invention relates to back frames suitable for attachment to a
backpack, rucksack, or similar.
Background of the invention
External back frames (also known as pack frames or backpack frames) are
typically utilised when a wearer is required to carry heavy loads upon his or
her back. In
one example, external back frames are worn by military or combat personnel.
Such
external back frames provide greater support, weight distribution, and wearer
protection
as compared to frameless backpacks or backpacks comprising an internal back
frame.
U.S. patent no. 7,793,809 describes an external back frame that is
particularly
suited to military application. This back frame comprises a one-piece unit
having a pair
of spaced generally parallel vertical side rails that are joined by generally
parallel top
and base cross-structures. This back frame is sized and dimensioned so as to
be
suitable for a wearer of a particular height.
It is an object of the present invention to provide a back frame that
overcomes, or
at least ameliorates, one or more deficiencies of prior back frames, or at
least provides
a useful alternative.
Reference to any prior art in the specification is not an acknowledgment or
suggestion that this prior art forms part of the common general knowledge in
any
jurisdiction or that this prior art could reasonably be expected to be
understood,
regarded as relevant, and/or combined with other pieces of prior art by a
skilled person
in the art.
Summary of the invention
In a first aspect, the invention provides a back frame that includes a first
part and
a second separate part configured to disengagingly interlock at plural
relative positions
to define respective assembled configurations of the back frame of two or more
distinct
lengths, whereby the back frame is adjustable for wearers of different
heights. The
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interlocking includes releasably interengaging the first and second parts by
relatively
moving the first and second parts in a first direction generally toward each
other and
then in a second direction generally perpendicular to the first direction.
The relative movement of the first and second parts in the second direction
may
comprise the first and second parts sliding over each other.
In an embodiment, the back frame includes one or more first formations on one
of the first and second parts and a plurality of second formations on the
other of the first
and second parts, the or each first formation selectively engaging the
respective second
formations to define the respective assembled configurations of the back frame
when
the first and second parts are releasably interengaged.
The first and second formations may be disengaged by relatively moving the
first
and second parts in a direction opposite to the second direction and then in a
direction
opposite to the first direction. The first and second parts of the back frame
may be
wholly separable when the first and second formations are disengaged.
The first formation may comprise a projecting locking formation and the second
formations may comprise apertures, wherein when the first and second parts are
relatively moved in the first direction the projecting locking formation is
received in a
selected opposed aperture. The apertures may be generally rectangular or
rhomboid in
shape, and are preferably dimensioned to receive the locking formation.
The first part of the back frame may include a locking formation and the
second
part of the back frame then includes a plurality of the opposed apertures.
Furthermore,
the second part of the back frame may then include a locking formation and the
first part
of the back frame may include a further plurality of apertures.
In an embodiment, the or each locking formation comprises a generally L-shaped
projection which slidingly engages a peripheral wall of the respective opposed
aperture
so as to be releasably wedged therein. The or each L-shaped projection may be
adapted to slidingly engage the peripheral wall of the respective opposed
aperture by
relatively sliding the first and second parts of the back frame over each
other in the
second direction.
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Preferably, there are four of the locking formations arranged in a rectangular
array, which is advantageous for rigidity in the respective assembled
configurations.
The first and second parts may each include a pair of spaced generally
parallel
side rails and one or more spaced cross-structures joining the side rails,
wherein each
side rail has therethrough a plurality of the aforesaid apertures arranged in
a linear array
along the respective side rail.
The first and second parts are preferably substantially symmetrical about a
vertical centreline parallel to the side rails.
In an embodiment, one of the one or more spaced cross-structures has,
integrally
formed therewith at a position between the side rails, a lumbar support member
that
projects without further support from the one cross-structure so as to be
inclined to a
plane, optionally curved, containing the side rails.
The back frame may further include a releasable latch arrangement that must be
released e.g. by hand, in a first action to allow disengagement of the first
and second
parts from interlocking engagement. The latch arrangement may comprise one or
more
further locking formations located on one of the frame parts which further
locking
formation is receivable within plural said apertures of the other part and
when therein
abuts a peripheral wall of the respective aperture when the first and second
parts are
interengaged thereby preventing relative sliding between the first and second
parts, and
thereby interlocking the first and second parts.
In an embodiment, the or each further locking formation is provided on a
respective tab configured to be resiliently flexed e.g. by finger pressure, in
said first
action.
There may be a pair of the latch arrangements at respective sides of the back
frame.
The lumbar support member and the one cross-structure are dimensioned so that
the lumbar support member contacts a lumbar region of the wearer's back when
the
back frame is being worn, and are preferably configured so that the lumbar
support
member is able to elastically flex during such contact.
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In a preferred embodiment, the first and second parts are curved so as to
follow
or approximate a typical curvature of a wearer's back.
In a preferred embodiment, the first part and/or the second part include one
or
more first attachment points such that the back frame may be releasably
attached to a
backpack, rucksack, or the like. Preferably, the first part and/or the second
part further
include one or more second attachment points that are dimensioned to receive
straps,
such as hip, waist, or shoulder straps.
Preferably, the first and second parts are dimensioned such that the back
frame
is adjustable to vary its length by up to, 150mm, for example, up to 120mm.
Preferably, the first and second parts are respective unitary single
mouldings.
In a second aspect, the present invention provides a back frame comprising:
a pair of spaced generally parallel side rails that define a plane, optionally
curved, containing the side rails; and
one or more spaced cross-structures joining the side rails, wherein said one
cross-structure has, integrally formed therewith at a position between the
side rails, a
lumbar support member that projects without further support from the one cross-
structure so as to be inclined to said plane;
wherein the lumbar support member and the one cross-structure are
dimensioned so that the lumbar support member contacts a lumbar region of a
wearer's
back when the back frame is being worn, and are configured so that the lumbar
support
member is able to elastically flex during said contact.
Preferably, the lumbar support member is generally of inverted U-shape.
Preferably, the lumbar support member is upstanding from said one cross-
structure when the backpack is worn in the correct orientation.
As used herein, except where the context requires otherwise, the term
"comprise" and variations of the term, such as "comprising", "comprises" and
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"comprised", are not intended to exclude further additives, components,
integers or
steps.
Further aspects of the present invention and further embodiments of the
aspects
described in the preceding paragraphs will become apparent from the following
description, given by way of example and with reference to the accompanying
drawings.
Brief description of the drawings
Figure 1 is a front perspective view of a back frame according to an
embodiment
of the invention;
Figure 2A is a front view of a first, lower, part of the back frame of Figure
1,
constituting a base frame;
Figure 2B is a front view of second, separate and upper, part of the back
frame of
Figure 1, constituting a top frame;
Figure 3A is respectively a front elevation and a partial cross-sectional
view, on
the line A-A, of the first and second separate parts of the back frame of
Figure 1 in a
fully disengaged or unassembled configuration;
Figure 3B comprises views similar to those of Figure 3A but with the back
frame
parts in a partially engaged configuration or partially assembled
configuration;
Figure 3C compares views similar to those of Figure 3A but with the back frame
parts in a fully engaged or assembled configuration; and
Figure 4 is a close-up fragmentary perspective view of the back frame of
Figure
1, which view includes a latch mechanism.
In the figures, the "front view" illustrates a front side of the back frame
(or a front
side of the first and second separate parts). When in use, the front side
faces the
wearer's back. When mentioned herein, a "rear view" is of a rear side of the
back frame
(or a rear side of the first and second separate parts). When in use, the rear
side faces
a backpack or other item carried by the back frame.
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Detailed description of embodiments
Referring to Figure 1, there is shown a back frame 10 for a backpack or the
like
that comprises a first part in the form of a generally rectangular base frame
12, and a
second separate part in the form of generally rectangular top frame 14. The
base frame
12 and the top frame 14 are transversely and longitudinally curved, or are
generally
concave, so as to follow or approximate a typical curvature of a wearer's
back. The
base frame 12 and the top frame 14 disengagingly interlock at plural relative
positions to
define respective assembled configurations of the back frame 10 of two or more
distinct
lengths (a first length being illustrated in Figure 1). In this manner, as
described in
further detail below, the back frame 10 is adjustable for wearers of different
heights.
The base and top frames 12, 14 each include a pair of respective spaced
generally parallel vertical side rails 16, 18 that are joined by respective
generally
transversely extending cross-structures 20, 22. As illustrated in the figures,
the base
and top frames 12, 14 are each symmetrical about a vertical centreline
extending
through each frame. Each of base and top frames 12, 14 is a unitary single
moulding in
a suitable high strength plastic material eg a polycarbonate. The frames are
preferably
rigid but may exhibit some flexure under prescribed loads.
The base and top frames 12, 14 disengagingly interlock by means of
complementary locking formations and apertures located on each frame.
Projecting generally forwardly from the upper ends of side rails 16 of the
base
frame 12 are a pair of first formations in the form of projecting locking
formations that
comprise generally inverted L-shaped projections 24 (see Figure 2A). The
projections
24 are generally inverted L-shaped when viewed in cross-section and are
generally
rectangular when viewed front-on. In an assembled configuration of the back
frame 10
(see Figure 1), the first pair of L-shaped locking projections 24 of the base
frame 12 are
releasably received in a respective pair of a plurality of second formations
in the form of
generally rectangular or rhomboid-shaped apertures 30 in side rails 18 of the
top frame
14. Each side rail 18 has a linear array of equispaced apertures 30.
Similarly, projecting generally rearwardly from a lower end of each side rail
18 of
the top frame 14 are a second pair of locking formations 28 similar in form to
projections
24 (see Figure 2B). In the assembled configuration, the second pair of L-
shaped locking
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projections 28 of the top frame 14 are releasably received in a respective
pair of a
plurality of similar vertically arrayed generally rectangular or rhomboid-
shaped apertures
26 that are equi-spaced-apart along each side rail 16 of the base frame 12
(see Figure
2A). As illustrated in Figures 2A and 2B, the first pair of L-shaped
projections 24 project
in an opposite direction to the second pair of L-shaped projections 28, such
that the L-
shaped projections 24, 28 releasably wedge within a respective opposite
aperture in an
assembled configuration, as is described below.
Advantageously, when the first and second pairs of L-shaped locking
projections
24, 28 are interengaged with the respective opposed apertures 30, 26, the base
and top
frames 12, 14 are firmly interlocked at all four positions. The base and top
frames 12, 14
are particularly rigidly interlocked due to the arrangement of the four L-
shaped locking
projections 24, 28 being on opposite side rails 16, 18 of the base and top
frames 12, 14
respectively.
The interengagement between the base and top frames 12, 14 to form the
assembled back frame 10 will now be described with reference to Figures 3A to
3C.
Figure 3A illustrates the base and top frames 12, 14 overlapping in close
proximity but
in a fully disengaged or unassembled configuration. As can be particularly
seen in the
cross-sectional view of Figure 3A, the first L-shaped locking projection 24 of
the base
frame 12 (shown in hatched lines) is located adjacent to, but removed from,
the
opposing aperture 30 of the top frame 14 (shown in cross-hatched lines).
Similarly, the
second L-shaped locking projection 28 of the top frame 14 is located adjacent
to, but
removed from, the opposing aperture 26 of the base frame 12. In this position,
the top
and base frames 12, 14 are fully disengaged or separate, but may be partially
engaged
by pushing each frame 12, 14 generally inwardly (or together) as illustrated
by the
arrows 102 in Figure 3A.
Referring now particularly to the cross-sectional view illustrated in Figure
3B, the
first L-shaped locking projection 24 of the base frame 12 is now received
within, or
located within, the opposing aperture 30 of the top frame 14. Similarly, the
second L-
shaped locking projection 26 of the top frame 14 is now received within the
opposing
aperture 28 of the base frame 12. In this position, the top and base frames
12, 14 are
partially engaged or partially assembled, but may be fully engaged or fully
assembled
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by sliding each frame 12, 14 in generally opposite directions parallel to side
rails 16, 18
(as indicated by the vertical arrows 104 in Figure 3B).
Referring now particularly to the cross-sectional view illustrated in Figure
3C, the
first L-shaped locking projection 24 of the base frame 12 has slidingly
engaged
orthogonal peripheral walls 30a of the opposed aperture 30 of the top frame
14.
Similarly, the second L-shaped locking projection 28 of the top frame 14 has
slidingly
engaged orthogonal peripheral walls 26a of the opposed aperture 26 of the base
frame
12. In this sense, the L-shaped projections 24, 28 are releasably wedged
within the
opposed apertures 30, 26 (or against the peripheral walls 30a, 26a thereof).
The base
and top frames 12, 14 are now fully interengaged such that the back frame 10
is now
fully assembled at one of the plural relative positions.
The base and top frames 12, 14 are disengagingly interlocked in this position
by
a latch arrangement comprising a pair of similar latches 100 symmetrically
arranged at
opposite sides of the assembly when viewed from the rear or front. Each latch
100
comprises an angled elongate planar tab 50 cut from within an enlarged upper
end
portion 17 of a respective rail 16 of base frame 12 so that the tab remains
attached at its
inner vertical edge 51 (Fig 2A), whereby the tab is hinged at this edge and
able to be
resiliently flexed from its rest position flush with end portion 17. The inner
end of tab 50
near the hinge edge has an integral L-shaped internal land or projection 40
that, when
the base and top frames are in their fully interengaged assembled condition as
described above, engages two edges of an aperture 30 of the rail 18 of the top
frame
14. By doing this the L-shaped lands or projections 40 lock the rail pairs,
and therefore
the frame, together by preventing inadvertent relative sliding of the rail
pairs that might
release the engagements between projections 24, 28 and apertures 26, 30. Such
inadvertent disengagement is a risk in the field, especially with heavily
loaded packs in
challenging conditions.
Lands or projections 40 can be unlatched from aperture 30 by resiliently
pressing
the free ends 52 of tabs 50 in the direction of the arrow "PRESS" in Figure 4.
This is the
first step of a three action movement required to disengage the base and top
frame for
adjusting the length of the back frame.
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Thereafter, the base and top frames 12, 14 may be slid longitudinally and
parallel
to side rails 16, 18 with respect to each other back to the partially engaged
position
illustrated in Figure 3B. In this position, the base and top frames 12, 14 can
then be
separated by pulling each frame generally away from one another (or at least
one of the
frames away from the other) ¨ the base and top frames 12, 14 have now returned
to the
fully disengaged position illustrated in Figure 3A.
It will be appreciated that the position of the L-shaped locking projections
24, 28
within the respective opposed apertures 30, 28 defines the overall length (or
height) of
back frame 10. For example, if the L-shaped locking projections 24 of the base
frame 12
were located within the lowermost opposed apertures 30 of the top frame 14,
the back
frame 10 will be at its maximum length. However, if the L-shaped locking
projections 24
of the base frame 12 were located within the uppermost opposed apertures 30 of
the
top frame 14, the back frame 10 will be at its minimum length. The back frame
10 is
designed such that the difference between its maximum and minimum lengths, ie
the
range over which the back frame is adjustable, is 120mm, represented by five
30mm
increments. In general, this difference, or adjustment range, may be up to
150mm. For
the Australian population, the variation in back length 1 percentile female to
99
percentile male is 153mm: an adjustment range of 120mm is thought acceptable
to
cover this 98% of the population group.
Certain other features of the illustrated back frame 10 will now be described.
Referring particularly to Figures 1 and 2A, the base frame 12 includes a
generally
inverted U-shaped lumbar support member 60 integrally formed with a lowermost
transversely extending cross-structure 20. The U-shaped lumbar support member
60
projects without further support from the lowermost cross-structure 20 so as
to be
inclined to a plane containing the side rails 16. The U-shaped lumbar support
member
60 and the lowermost cross-structure 20 are dimensioned such that the lumbar
support
member 60 contacts a lumbar region of a wearer's back when the back frame 10
is
worn (not shown). Advantageously, the U-shaped lumbar support member 60
exhibits a
resilient hinging action such that it is able to elastically flex during such
contact, thereby
providing responsive support to the lumbar region of the wearer's back. The
back frame
10 comprises a moulded material, such as a suitable polycarbonate, that is
able to
elastically deform.
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The base and top frames 12, 14 further include a plurality of generally
elongate
pill-shaped attachment slots 70 disposed on side and end structures or wings
71 of
each frame. As illustrated in Figure 2A, the base frame 12 includes
symmetrically
arranged elongate attachment slots 70 located about the hips of the wearer
(when the
back frame 10 is worn). Similarly, the top frame 14 includes symmetrically
arranged
attachment slots 70 located about the upper and side regions of the shoulders
of the
wearer (when the back frame is worn). The attachment slots 70 are utilised to
releasably attach the back frame 10 to a suitable backpack, rucksack, or
similar (not
shown). The attachment slots 70 are also utilised to releasably receive one or
more
straps or belts, such as hip, waist, or shoulder straps (not shown). The
configuration,
shape and number of slots 70 and of side and end structures or wings 71, may
of
course vary according to the intended use of the back frame.
It will be understood that the invention disclosed and defined in this
specification
extends to all alternative combinations of two or more of the individual
features
mentioned or evident from the text or drawings. All of these different
combinations
constitute various alternative aspects of the invention.
