Improvements in and relating to backpacks

Abstract: A backpack (10) has a compartment (12) for items to be transported on the back of a carrier and a back frame (18) comprising at least one vertical stay (20) having a top end and a bottom end and at least one horizontal stay (22, 24), the vertical stay being generally S-shaped and the horizontal stay having a generally concave shape, at least one of the stays being made of a material that can be deformed to a desired shape.

Description: This invention concerns improvements in and relating to backpacks. Backpacks generally comprise a bag having usually one main and other smaller compartments to be carried on the back by means of shoulder straps and optionally a hip belt. Human backs have a shallow "s" shape vertically and a convex shape horizontally. Desirably that part of the bag (backpack) which contacts the back should have a similar shape in order to spread the load over the back. Additionally, it is desirable to bring the centre of gravity of the load being carried as far forward as possible, so that there is less likelihood of the carrier having to lean forwards, which can cause back strain. The main way of trying to achieve a desirable back panel shape is to include in or on the backpack a frame which can control the shape of the back panel. A common internal frame has a pair of vertical stays. Unfortunately, that type of frame often produces a most undesirable back panel shape. When backpacks with that type of frame are packed, the back panel tends to round into a convex shape horizontally, which is the opposite of a natural back shape. That concentrates the load down the spine and puts the centre of gravity of the load far from the back, causing a stooping posture for the carrier and hence back strain. Another type of internal frame system is a flat plastic frame sheet. That keeps the back panel flat, so that the above-mentioned undesirable convex shape is avoided and brings the centre of gravity of the load nearer to the back. Whilst posture is improved and back strain lessened with this system, it is not entirely satisfactory because the load is not spread over the full width of the back. External frame systems can achieve a concave shape for a backpack but have other drawbacks. Such frames are generally rigid and constructed from relatively thick stays. The thickness of the frame increases the distance between the backpack and the back, which puts extra strain on the back. These frames cannot be bent to match the back shape and they have a high centre of gravity making them top heavy for active endeavours, such as skiing. Furthermore, the rigid frame resists body movement and the frame is bulky and awkward to manage. US-A-4040548 discloses a backpack having a compartment for items to be transported on the back of a carrier, the backpack having a back frame comprising at two vertical stays and horizontal stays, the two vertical stays being generally S-shaped to present to the carrier's back a lower convex part, a middle concave part and an upper convex part and one of the horizontal stays having a generally concave shape and being positioned so that it will lie across the lower convex part of the vertical stays, at least one of the stays being made from a material that is deformable to a desired shape. An object of this invention is to improve backpack frames in order to eliminate or at least reduce the effect of the above-mentioned disadvantages of known backpack frames. According to this invention there is provided a backpack having a compartment for items to be transported on the back of a carrier, a back frame comprising one central vertical stay and at least one horizontal stay, the vertical stay being undulating form to present to the carrier's back a lower convex part followed by a concave part, and the at least one horizontal stay having a generally concave shape in a horizontal direction and being positioned so that it will lie across the lower convex part of the vertical stay, at least one of the stays being made of a material that is deformable to a desired shape. In a preferred embodiment the vertical stay comprises a lower convex part followed by a concave part, and an upper convex part. In another preferred embodiment the back frame comprises one vertical stay and two horizontal stays, the horizontal stays extending to either side of the vertical stay. The "S" shape of the vertical stay is chosen to follow generally the normal contours of the back but preferably can be adjusted by bending to match more closely the back shape of the person who will carry the backpack. One of the horizontal stays is preferably positioned so that it will lie across the carrier's back at or near shoulder height. The lower horizontal stay is positioned so that it will lie across the small of the back at above waist height. The upper horizontal stay may be at the top end of the vertical stay, although for some embodiments it is preferred that the vertical stay extend further upwards and rearwardly relative to the carrier of the backpack to allow for head movement without restriction. For additional support a relatively rigid sheet member may be provided above the upper horizontal stay, the sheet being generally shaped to give the upper part of the backpack a concave shape. A similar sheet may be provided in a lower region of the backpack, preferably below the lower horizontal stay. This lower sheet is ideally shaped to follow the curve of the main vertical stay. The frame may further comprise outer frame members along side corners of the backpack at or beyond each of the horizontal stays but not necessarily connected thereto. These outer members are preferably of flexible material, such as plastics rod and may be shaped to follow the general contours of the back i.e. may also be S-shaped. In one preferred embodiment, the backpack further comprises an outer frame member which is a continuous inverted generally U-shaped member. The preferred material for horizontal and single vertical stays of any embodiment of the invention is one that once bent into a particular shape will substantially retain that shape. Aluminium and aluminium alloys are preferred materials for these stays. The components of back frames of the inventions are preferably fitted in sleeves of the backpack preferably as separate items, so that they can be removed for bending to a desired configuration to suit the back shape of the person to carry the backpack. When outer flexible frame members are provided in a backpack, preferably their lower parts are bent forwards so as to lie more or less on the carrier's sides rather than back. Usually however, the backpack will curve rearwards in that region following the back's contour, in which case, the flexible outer frame members will have their lower parts connected to the backpacks by connecting panels or webs. Because of the shaping of backpacks of the invention due to its frame arrangement, it may be necessary to make the back panels from specially shaped fabric pieces. Preferably a three part construction is used for backpacks of the first embodiment of the invention comprising a pair of vertical panels fastened side by side that extend over a major part of the back panel and a top horizontal panel. The vertical panels when laid flat are mirror images of each other and preferably have a gentle overall S-shape. The top panel when laid flat is preferably curved, its inside curve being fastened to stop edges of the other vertical panels. The top panel may be omitted for other embodiments of the invention. For carrying a backpack shoulder straps are usually provided that extend from an upper part of the backpack over the shoulder to a lower part of the backpack. Additionally, a hip belt may be provided. Shoulder straps and hip belts are generally padded for comfort but often there is insufficient give in the shoulder straps or hip belt for comfort. To overcome the above-identified problem with shoulder straps and hip belts, it is proposed according to the invention that either or both be made of an elastic material stretchable in desired directions. Preferably means will be provided to constrain stretching of the elastic material in undesired directions. Thus, for a shoulder strap lateral stretching is desirable to suit different shoulder shapes or slopes, whereas vertical stretching is undesirable over the whole length of the shoulder strap. For a hip belt stretching to accommodate different hip shapes is desirable but stretching at waist level is not to avoid the hip belt from slipping downwards. A shoulder strap for a backpack or the like is preferably made of an elastic material which is constrained against stretching in a lengthwise direction over at least part of its length. Thus, a shoulder strap of the invention may stretch horizontally to fit more closely to the shape of the carrier's shoulder and to follow the body shape below the arms. Furthermore, the elastic nature of the strap absorbs the shock of the load of the backpack and gives with shoulder movements. To constrain an elastic shoulder strap against vertical stretching, one or more strips of generally non-stretchable fabric may be fixed to the shoulder straps extending vertically. Fixing of the non-stretchable fabric may be by any suitable means, such as, for example, by stitching or by adhesive. A suitable elastic material for shoulder straps of the invention is a rubber material, such as neoprene, preferably with a stretch fabric laminated to either or both sides. Shoulder straps according to this aspect of the invention may be used on backpacks according to the first aspect of the invention as well as other backpacks or indeed other shoulder carrier items. Similar considerations also apply to hip belts for backpacks. Most hip belts for backpacks are either parallel sided or conically cut. Parallel sided hip belts have to be pulled tightly to grab a persons sides so the hip belt does not slip down. Conically cut hip belts try to solve this problem with a narrower fit at the top. However, this creates pressure points at the top of the hip bone, where there is little muscle, causing bruising. Hip belts for backpacks of the invention preferably comprise a band of relatively stretchable fabric surmounted by a band of relatively non-stretchable fabric. The invention will now be further described, by way of example only, with reference to the accompanying drawing, in which:- Figure 1 shows a first backpack according to the invention; Figure 1A shows a variation of the backpack of Figure 1; Figure 2 shows a second backpack according to the invention; Figures 3 and 4 show the frames for the backpacks of Figures 1 and 2 respectively from the side in relation to a carrier's body; Figures 5 and 6 show fabric patterns for alternative back panels of the backpack of Figure 1; Figure 7 shows fabric patterns for a back panel of the backpack of Figure 2; Figure 8 shows shoulder straps for a backpack or the like; and Figure 9 shows a hip belt for a backpack or the like. Referring to Figure 1 of the accompanying drawings, a backpack 10 comprises a main bag compartment 12. Smaller side or rear compartments may be provided but these are not shown for simplicity. The compartment 12 has a closure flap 14, which may be fastened in any suitable way. The backpack 10 has a back panel 16, which lies against the back of a carrier. The back panel 16 includes a frame 18 made up of separate components that are contained in fabric sleeves. The frame 18 comprises a main vertical stay 20 of a material that can be bent to a desired shape and retain that shape, i.e. a shape memory material, such as a flat strip of aluminium. The stay 20 has a basic shallow S-shape to suit the general contour of the human back. Two horizontal stays 22 and 24 are provided which are shaped to give a concave appearance to the back panel. Those stays are made of the same material as the vertical stay. The upper stay 22 is intended to be in the region of the shoulders of the carrier and the lower stay 24 is in the region of the small of the back. The vertical stay 20 does extend slightly above the upper horizontal stay 22 where it curves rearwards so that in use the backpack does not interfere with head movement. An additional support in the form of a flat curved sheet 26 is provided just above the upper stay 22. In the variation shown in Figure 1A of the drawings, there is an additional support in the form of a flat curved sheet 34 in the lower part of the back panel 16 below the horizontal stay 24. Additionally, a web 36 extends between the bottom ends of the vertical stays 28 and behind the sheet 34. In all other aspects the variation of Figure 1A is as the backpack shown in Figure 1. Along the sides edges of the back panel flexible plastic rods 28 are provided. These are generally arcuate in side view. Over a lower part of the rods 28, the back panel curves rearwards whilst the rods curve forwards. The rods remain connected to the back panel in that region by either fabric panels 30 as shown on the left of the illustrated backpack or by fabric webs 32 as shown on the right. The backpack 10 will have shoulder straps and a hip belt but these have been omitted from the drawings for simplicity. As can be seen from Figure 3 of the drawings, the frame 18 allows the backpack to fit snugly onto the back of the carrier. For additional comfort, the vertical and horizontal stays 20, 22 and 24 can each be removed from their respective sleeves and bent to suit the shape of the carrier's back more closely. Because the back panel of the backpack of Figure 1 is constrained by its frame to take a particular shape, the back panel is ideally produced from three fabric panels as illustrated in Figures 5 and 6 of the accompanying drawings. The difference between the two drawings is that Figure 5 is for a back panel with connecting panels 30 and Figure 6 is for a back panel with webs 32. The three fabric panels are generally a top horizontal panel 40 and two vertical panels 42 and 44 which are mirror images of each other. The top panel 40 is generally arcuate and the two vertical panels 42, 44 have a gentle S-shape. The edges of each panel to be joined together preferably by stitching are indicated by double-headed arrows. Turning to Figure 2 of the accompanying drawings, a backpack 60 is shown which is a zip opening pack with a curved top. The pack 60 has a back panel 62 and a frame 64 made of separate components fitted in sleeves (not shown) of the back panel. The frame 64 has vertical stay 66 centrally of the back panel made of a shape memory material and generally S-shaped when viewed from the side to follow the contours of a human back. A horizontal stay 68 is provided in a lower part of the back panel and is arcuate so as to produce a concave shape for the back panel. Finally, a hoop 70 of flexible plastic rod is provided around the perimeter of the back panel. The flexible hoop 70 has legs 72 whose lower ends curve forwards away from the back panel but remain connected by connecting panels 74 or by connecting webs. The vertical and horizontal stays are removable from their respective sleeves so that they can be bent to shape to suit the carrier. How the backpack 60 fits a carrier's back is shown in Figure 4 of the drawings. To enable the back panel 62 to take up more easily a shape determined by the frame the back panel is made from specially shaped fabric panels 74 and 76 as shown in Figure 7 of the drawings. Carrying straps for this backpack have been omitted from the drawings for simplicity but would include shoulder straps and probably a hip belt. Shoulder straps suitable for the illustrated backpacks or indeed any other type of backpack are shown in Figure 8 of the accompanying drawings. The shoulder straps 200 illustrated are made of an elastic material such as neoprene laminated on both sides with a stretch fabric so that they can stretch as indicated by the broken lines to accommodate different shoulder shapes and slopes. However, to restrain excessive stretching of the material vertically, webs 202 are stitched onto the shoulder straps. The webs 202 are narrow relative to the shoulder straps so that the elastic material either side thereof can still stretch to curve at its sides to follow the body contour, especially near the arm pits. The shoulder straps 200 will be fastened to a back panel in a conventional manner including the provision of length adjustment. A similar principle is used in forming the hip belt 300 shown in Figure 9 of the accompanying drawings. The hip belt 300 will be connected to lower parts of a backpack and is intended to fit around the carrier's hips. The hip belt 300 is made of main band 302 of elastic material, such as neoprene laminated with stretch fabric on both sides, and a top band 304 of generally non-elastic material stitched to the main band. The hip belt is fastened by a buckle 306. The main band 302 forms a lower section of the hip belt which in use will stretch vertically and laterally to mould itself to the hip shape of the carrier whilst the non-elastic top bands sits around the waist and prevents the hip belt from slipping downwards. The elastic nature of the main band allows extended leg movement and avoids pressure points.

Claims: A backpack (10) having a compartment (12) for items to be transported on the back of a carrier, a back frame (18) comprising one central vertical stay (20) and at least one horizontal stay (68), the vertical stay (20) being of undulating form to present to the carrier's back at least a lower convex part followed by a concave part, and the at least one horizontal stay (68) presenting a generally concave shape in a horizontal direction to the carrier's back and being positioned so that it will lie across the lower convex part of the vertical stay (20), at least one of the stays being made of a material that is deformable to a desired shape. A backpack (10) as claimed in claim 1, wherein the vertical stay (20) comprises a lower convex part, followed by a concave part, and an upper convex part. A backpack (10) as claimed in any one of claims 1 or 2, wherein the back frame (18) comprises two horizontal stays (22,24) extending to either side of the vertical stay (20). A backpack (10) as claimed in claim 3, wherein one of said two horizontal stays is an upper horizontal stay (22) positioned to lie across the upper convex part of the vertical stay (20). A backpack (10) as claimed in claim 3 or 4, further comprising a relatively rigid sheet member (26) above the upper horizontal stay (22), the sheet (26) being generally shaped to give the backpack (10) a concave shape in a horizontal direction in that region. A backpack (10) as claimed in any one of claims 1 to 5 further comprising a relatively rigid sheet member (34) below the lower horizontal stay (24), the sheet (34) being generally shaped to give the backpack (10) a concave shape in a horizontal direction in that region. A backpack (10) as claimed in any one of claims 1 to 6, wherein the frame (18) further comprises outer vertical frame members (28) along side corners of the backpack (10) at or beyond each of the horizontal stays (22,24) and optionally connected thereto. A backpack (10) as claimed in claim 7, wherein the outer frame members (28) are of flexible material. A backpack (10) as claimed in claim 7 or 8 with claim 6 further comprising a web (36) linking bottom ends of the outer frame members (28) and passing behind the lower sheet member (34). A backpack (10) as claimed in any one of claims 1 to 9, wherein the central vertical stay (20) is made of a material that once bent into a particular shape will substantially retain that shape. A backpack (10) as claimed in any one of claims 1 to 10, wherein the central vertical stay (20) is made of a material selected from aluminium and aluminium alloys. A backpack (10) as claimed in any one of claims 1 to 11, wherein the or each horizontal stay (22,24) is of a material that once bent into a particular shape will substantially retain that shape. A backpack (10) as claimed in any one of claims 1 to 12, wherein the or each horizontal stay (22,24) is made of a material selected from aluminium and aluminium alloys. A backpack (10) as claimed in any one of claims 1 to 13, wherein frame components are fitted in sleeves of the backpack. A backpack (10) as claimed in any one of claims 1 to 14, having shoulder straps (200) made of an elastic material and, where the shoulder straps (200) are stretchable laterally but constrained against stretching lengthwise over at least part of their length. A backpack (10) as claimed in any one of claims 1 to 15, having a hip belt (300) of an elastic material, wherein the hip belt (300) has an upper section (304) and a lower section (302) and is stretchable vertically and laterally in lower sections (302) but constrained against stretching laterally and vertically in the upper section (304). A backpack (60) as claimed in claim 1, wherein the backpack (60) further comprises an outer frame member (70) which is a continuous inverted generally U-shaped member. A backpack (60) as claimed in claim 17, wherein the outer frame member (70) is of flexible material. A backpack (60) as claimed in claims 17 or 18, wherein the outer frame member (70) is shaped to follow the contours of a carrier's back. A backpack (60) as claimed in any one of claims 17, 18 or 19, wherein the central vertical stay (66) is of a material that once bent into a particular shape will substantially retain that shape. A backpack (60) as claimed in any one of claims 17 to 20, wherein the central vertical stay (66) is of a material selected from aluminium and aluminium alloys. A backpack as claimed in any one of claims 17 to 21, wherein horizontal stays (68) are of a material that once bent into a particular shape will substantially retain that shape. A backpack as claimed in any one of claims 17 to 22, wherein horizontal stays (68) are made of a material selected from aluminium and aluminium alloys. A backpack as claimed in any one of claims 17 to 23, wherein frame components are fitted in sleeves of the backpack. A backpack as claimed in any one of claims 17 to 24, having shoulder straps (200) made of an elastic material and wherein the shoulder straps (200) are stretchable laterally but constrained against stretching lengthwise over at least part of their length. A backpack (60) as claimed in any one of claims 17 to 25 having a hip belt (300) made of an elastic material, wherein the hip belt (300) has an upper section (304) and a lower section (302) and is stretchable vertically and laterally in the lower section (302) but constrained against stretching laterally and vertically in the upper section (304).

Inventors: TATE AARN, TATE, AARN
Applicants: TATE AARN, TATE, AARN
Application year: 1996
Main classification: A45F3
IPC codes: A45F3