Backpack systems

A scuba pack is disclosed that enables a user to carry a substantial back supported load with comfort and mobility. The pack has a flexible load container having a base panel for engagement on the back of a user, wherein the base panel having extensions fitting over each shoulder and around a portion of the waist of the user. The pack also has a harness disposed on the front of the user, which adjustably interconnects the extensions of the flexible load container across the front waist of the user. The harness also adjustably interconnects the shoulder extensions to the waist extensions. The harness is longitudinally flexible within a selected range, such that load forces are transmitted to the waist region while holding the load in conformity to the user without restricting body movement.

BACKGROUND OF THE INVENTION 
This invention relates to backpack systems for carrying loads without the 
use of a rigid frame structure, and more particularly to improved systems 
for bearing loads with less fatigue and without restricting the mobility 
of the user, such as buoyancy compensated jackets for scuba divers. 
The problem of increasing the load carrying capacity of a person has been 
attacked in various ways through recorded history. Depictions carried down 
from earlier civilizations have shown that very large burdens have been 
transported by humans, such as through the use of tump lines extending 
across the forehead for a load carried on the back, and loads suspended on 
either side of a person from a beam balanced on the shoulders. Where no 
road system exists, or where loads have had to be transported across 
arbitrary terrain, as in military operations, many supports have been 
devised and used. Until about the end of the first half of the twentieth 
century, these usually comprised a rigid frame with little or no 
conformity to the back of the user, and a shoulder strap and belt 
arrangement that was often unpadded. The center of gravity of the load was 
well out from the back so that the pull on the shoulder straps was often 
extremely tiring, and the frame itself was often heavy and added 
substantially to the base weight. These types of packs were supplemented a 
number of other types, including those known as "Trapper Nelson" and "A 
frame" packs. These would typically be lighter but otherwise suffered from 
most of the same deficiencies although they were widely used. 
Shortly after the first half of the twentieth century, however, there was 
increasing growth in recreational backpacking, and a new market opened up 
for backpacks of a different type. These were usually more costly, but 
they enabled users to carry a given load with greater comfort, such as the 
"Kelty" pack introduced by the A. I. Kelty Company. The frame was made of 
welded aluminum curved to conform closely to the back of the user, and the 
pack was removably attachable, and positioned in such a way as to shift 
the center of gravity of the load both higher and more closely spaced to 
the back of the individual. The back was supported both by a wide waist 
belt and by adjustable shoulder pad and strap combinations. Thus the 
downward press of the load thus tended to be exerted more on the hips of a 
slightly forwardly leaning hiker. This design was followed by a diverse 
variety of pack frames, with both external and internal pack arrangements, 
for comfort and convenience. 
While a frame is generally needed for the highest capacity loads, there are 
a number of situations in which the frame restricts movement or occupies 
too much space. Therefore, soft packs, without frames or supports, are now 
widely used to carry moderate loads for recreational hiking, for their 
capability for storage in aircraft overhead compartments, for 
cross-country skiers, for climbers and others. Here there is a limited 
amount of conformity with the backpack, but because it is usually 
supported primarily by the shoulder straps, with limited support from the 
belt or waistband, the center of gravity of the pack tends to be displaced 
downwardly and outwardly. This further acts to limit the load carrying 
capacity and reduce the comfort of the user. In a number of situations, 
the mobility of the user, and control of backpack position and load 
movement are of primary importance, such as with the skier and the 
climber. In both instances, positive control over the load, and 
maintenance of the sense of balance of the user, without restriction of 
movement or the imposition of stressful loads, are of greatest importance. 
An even more critical example of this type of demanding situation is the 
backpack for a scuba diver. The pack should support one or two air 
cylinders, present low resistance to the water as the diver moves, and 
therefore have a low profile, while not acting to restrict the diving and 
swimming movements of the user. At the same time, conventional pockets for 
gear and holders for accessories should be included. Even more, it is 
desirable to incorporate a "buoyancy compensation" feature. This type of 
pack has an inflatable bladder or internal chamber, and can be expanded by 
oral inflation or by using air from the tank. Thus it provides a means for 
precisely compensating for the diver's weight belt and other equipment at 
a given depth, so as to minimize the work involved in maintaining a given 
location. Examples of this type of system are found in the U.S. Pat. Nos. 
to Greenwood, 3,436,777, Deeds, 4,054,132, Faulconer et al., 4,810,134, 
Walters, 4,952,095, Walters, 4,016,616, Faulconer et al., 4,561,853, 
Wright III, 4,137,585, Courtney, 4,779,554, and UK specification No. GB 
2197 627A. 
Though the earlier systems were bulky, the state of the art has improved 
considerably, and the present buoyancy compensated (or BC) packs have 
different combinations of adjustable shoulder straps, flexible or 
non-stretching waist straps, rigid and semi-rigid tank holders, and 
different arrangements for the buoyancy compartments and for storage and 
utility pockets. None have the desirable combination of features that are 
now sought, including particularly allowing the freedom of motion to the 
diver, especially when the bladder is inflated. Further they do not 
provide firm yet non-restraining retention of the tank in a low profile 
configuration, easy adjustment, and low cost construction. For example, 
U.S. Pat. Nos. 4,009,583, 4,016,616, 4,137,585 and 4,779,554 all have 
rigid tank holders and backpacks, while U.S. Pat. No. 4,009,583 also 
incorporates a semi-rigid air container system with a rigid cover. In U.S. 
Pat. No. 4,952,095 the backpack is flexible, with an interior liquid, and 
the container made of a flexible material, while the tank holder is rigid. 
In this example the waist straps are flexible neoprene, foam rubber, or 
rigid nylon webbing. In U.S. Pat. No. 4,810,134, the tank holder is rigid, 
the shoulder straps are non-extendable, and are adjustable only at D-rings 
or locked buckles. Flexible waistband straps of neoprene foam rubber are 
utilized, in accordance with U.S. Pat. No. 4,694,772, which describes a 
buoyancy compensation feature and is said to be automatic. None of these 
teachings provides a suitable combination of all the features that are 
desired. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a soft backpack that has superior 
load carrying capabilities comprises a unit including a central panel with 
shoulder and waist wings or extensions which only partially encompass the 
body of the user. A front harness system couples the wings together across 
the front of the body, the front harness system comprising an adjustable 
wide waistband having off center tensioning segments and shoulder straps 
coupled to the waist extensions, and also including intermediate 
tensioning segments and adjustable means. The stretchable portions of the 
waistband preferably comprise woven fabric webs having webs having 
neoprene strands in the stretch direction, and polyester and nylon strands 
in the transverse direction, the width typically being of several inches. 
This woven construction is permeable to the water, and therefor has little 
buoyancy, but more importantly has useful tension and stretch 
characteristics and no tendency to lose stretch upon use. Narrower 
extensible woven straps are used in the shoulder strap arrangement, and 
here the tension and stretch are less, because the vertical forces are 
divided between the two straps. 
The adjustable waistband and shoulder straps are positioned such that, even 
though they have high compliance and firmly hold the load, they do not 
resist body or limb motion in any significant way. When the jacket is 
inflated, the user has a freedom of motion that has not been attained 
heretofore. 
Because the tensioned portions of the front harness are interconnected, the 
load in the pack is maintained with a yielding tension in all directions. 
The harness distributes the tension, when the links of non-stretchable 
material are adjusted, so as to hold the pack securely in comfortable 
position while yielding to body movement in a fully compatible, 
non-restraining manner. The principal panel of the pack is preferably of 
two separate layers of closely woven fabric, coated on one or both sides, 
but coated on at least the interior sides. The layers are joined together 
along weld or baffle lines to define the internal buoyancy compensation 
chambers, using R.F. compression or heat techniques. In addition, a tank 
cradle may be formed in the back of the pack, by spaced apart fabric 
channels and structural foam inserts may be inserted in the channels on 
each side of the tank. These supported channels, together with tank 
straps, are sufficient to hold the tank firmly in position while providing 
a soft and compactible system. 
The jacket for scuba use preferably is constructed around a central double 
walled panel which is welded to delineate the internal bladder. The 
shoulder straps have internal padding and both outer and inner panels may 
be attached to the waist extensions to provide accessible pockets and base 
means for the waistband. 
The extensible portions of the harness are woven fabrics specially designed 
to satisfy the particular requirements of the application. In a specific 
example the waistband includes a 4" wide woven web having 30 gauge 
neoprene strands in the warp direction and nylon strands in the fill 
direction. This provides the needed "tension" and "stretch" as the term is 
used in the fabric art, and an anisotropic stretch property since there is 
stretch only in the longitudinal direction. The shoulder strap segments 
that are extensible are 1 1/2" wide and woven on a 45.degree. bias of 
neoprene and nylon strands to provide the tension and stretch selected for 
this portion of the harness. In one form of the invention a flexible 
sternum strap of about 1" width may be included, above the waistband, to 
hold the waist wings in close conformity to the body. 
In accordance with the invention, buoyancy compensator packs for underwater 
use are softer and more flexible than prior constructions, and substantial 
cost savings are effected by the design. Furthermore, the jacket may 
include a number of pockets which may be interchangeable and in different 
colors if desired. Further features of the system include an internal 
detachable clamping arrangement for the waistband, such that the elastic 
portion can be adjusted to different positions to accommodate different 
user dimensions, thus enabling economy of construction. 
In accordance with the invention, the gas holding bladder in the backpack 
can be of stretchable or non-stretchable plastic, fabric or rubber. The 
preferred example, however, is a nylon fabric from 400 to 800 denier 
coated as described previously. Alternatively, a blend of cordura and 
nylon from 400-800 denier, can be employed. 
The same principles of construction find utility soft backpacks for other 
purposes. The four-way adjustable harness, and the inter-connected aspects 
of the harness and central panel, insure that the load will be maintained 
firmly but compliantly on the body, with the center of gravity being as 
close as feasible to the upper back shoulders of the user, and moving 
constantly with the body so that the unitary response is achieved. In 
other words, the user feels that the load is secure, but not an impediment 
to movement entirely predictable. The snug fitting characteristic of the 
backpack need not tend to act to overheat the user, inasmuch as in this 
adaptation the panel can be a mesh or other air breathing material that 
provides a little insulative effect.

DETAILED DESCRIPTION OF THE INVENTION 
In the following description of the preferred embodiment, reference is made 
to the accompanying drawings which form a part hereof, and in which is 
shown by way of illustration a specific embodiment in which the invention 
may be practiced. It is to be understood that other embodiments may be 
utilized and structural changes may be made without departing from the 
scope of the present invention. 
A backpack in accordance with the invention is shown in FIGS. 1 to 8 that 
meets the demanding requirements of the scuba diving environment, and 
comprises a diver's jacket 10 of the buoyancy compensated type. The jacket 
10 has a central or principal panel 12 of two layers which are sealed 
(welded) together along baffle lines 16 as best seen in FIG. 5 to form a 
fluid retention bladder that may be filled and emptied for buoyancy 
compensation purposes. In this example, the fabrics used are cordura and 
nylon cloth of 400-800 denier which have urethane, rubber or neoprene 
coatings (neoprene being chosen in this example) on both or at least the 
inner surfaces, both surfaces being coated in this example. Nylon or 
cordura and nylon fabric 400-800 denier may be employed, and the central 
panel 12 and may be welded together by conventional means, with radio 
frequency welding being preferred, although compression and heat welding 
may also be utilized. 
The central panel 12 is configured to partially wrap around the diver, 
having shoulder wings or extensions 20, 22, as best seen in FIG. 7, that 
extend over the shoulder and down to the waist region of the diver. 
Additionally, as best depicted in FIG. 5, large waist wings or extensions, 
91, 92 extend partially about the side of the diver, being spaced apart at 
the central front region. At the back of the jacket 10, as seen in FIGS. 5 
and 6, a support 28 for the air tank is provided formed in part of a 
sectional cylindrical panel of engineering plastic such as Delrin, 
disposed under a fabric cover 30. Tank straps 34 and 36 (FIG. 6), 
configured concentric with the tank 38 (FIG. 8), extend through slots 94 
and 94' in tank support 28. The support 28 being attached to the back pad 
32, also called a "plush pad" on the central panel 12, to secure the tank 
38 in position. An air feed coupling 40 for coupling to tank 38 and an air 
release valve 42 are provided on the jacket 10. Inflation hose 39 couples 
air feed coupling 40 and an air release valve 42 to the tank 38 permitting 
the bladder to be inflated to a desired internal pressure in a 
conventional way by using the air tank 38 or a mouth piece (not shown), 
via the air feed valve 41 that is coupled to the tank 38. In addition, the 
jacket includes a relief of valve to prevent over inflation of the 
bladder. 
The characteristics of the strap and web materials that are used are 
imparted by conventional processes, such as weaving a band of given width 
with elastomeric strands in the warp direction and synthetic polymer 
strands in the fill direction with selected gauges and densities. The 
significant properties are that the strap or web stretches longitudinally 
and not substantially in the transverse direction, that it extends a 
particular distance in response to a given force, that if not change 
characteristics after repeated stretching, and that it be of substantially 
neutral buoyancy. These properties are achieved typically by the use of 
interwoven neoprene rubber compounds having gauges from 24 to 30, and 
polyester filaments of 2/150 size and type, in suitable combination of 
warp ends and elastomeric ends for the chosen width and mechanical 
characteristics. The nature of the weave can also be varied, as with the 1 
1/2" straps, which are on a 45.degree. bias. 
In the fabric industry, the characteristics of narrow fabrics are given in 
terms of "tension" defined in a particular way. Bench marks are placed 10" 
apart on a 16" specimen which is clamped at one end and has a test weight 
(here 15 lbs.) attached to the other end. The test weight is lowered 
gradually until supported by the fabric, and this is repeated three times, 
after which the weight is allowed to hang free and the distance between 
the bench mark is measured. The tension, in percent, is then given by: 
##EQU1## 
If, in other words, the distance between bench marks increases by 2 inches, 
the tension is 20%. Given this parameter, the different narrow fabrics 
used here have the following practical values for a scuba jacket, assuming 
a single air tank load: 
______________________________________ 
1" 75% tension 
11/2" 52% tension 
4" 30% tension 
______________________________________ 
Given these values for the stated application, it will be appreciated that 
different values may also be used without substantially affecting the 
mobility of the user. For different fabrics a range of .+-.30% has been 
found adequate for tension values. However, the entire scale is shifted to 
higher tensions if the load mass is substantially increased, and to a 
lower range if the load mass is less. 
Because of the placement of the extendable segments, and their 
intercoupling, they represent minor forces on the body even though they 
contribute in cooperative manner to distributing the load of the pack. The 
vertical forces relative to the height of the body exerted by the load act 
to tension the waist, thus distributing the load without stressing any 
particular body area. 
As best seen in FIG. 1, an upper strap coupling 43 having a loop 44 is used 
to feed a nonstretchable strap 45 through the loop 44 and coupling 43 
securing it to the jacket 10. Lateral loop 46 covers lower strap 48 
maintaining tension against the strap so that the jacket 10 is kept taut 
and streamlined against the diver's body. Longitudinal, flexible or 
"extensible" strap 48 is a section having a first end which is attached 
and adjustable in relation to upper coupling 43. Strap 48 is typically 1 
1/2" wide and may be weaved at a 45.degree. bias, but those skilled in the 
art will readily recognize that other widths and weaves can be 
advantageous dependent upon the size of the jacket. A second end of the 
longitudinal strap 48 is attached to a ring 50. Ring 50 may be tucked into 
a small pocket (not shown) formed in jacket 10 for streamlining. 
Lower coupling 47 comprises detachable mating male and female components. 
The lower component (male or female) is attached to a non-stretchable 
strap secured inside the waist wing while the upper component is attached 
to the central panel 12. 
Vent 54 is made of a mesh-like or porous material allowing drainage from 
the jacket 10. Zipper 56 provides an opening to a small front pocket in 
the waistband. Auxiliary ring 58 may be used for attachment of 
miscellaneous accessories used in the sport such as, but not limited to, 
skin diving. 
The jacket 10 being symmetrical is constructed in a similar manner on the 
opposite shoulder side. That is, elements 43-50 operate and are 
constructed in an identical fashion. 
A sternum strap 60 made of a flexible material is attached to the jacket 10 
and is concentric to the diver's waist. The strap 60 keeps the top of the 
waistband from flaring open. 
Now referring to FIG. 2, a better view of the plush pad 32 is depicted. 
Non-stretchable strap 45 is depicted sewn into the left upper corner of 
the jacket 10. A loose end 62 of the non-stretchable strap 45 is depicted 
to show the detail of the weaving through upper strap coupling 43. A strap 
is depicted having a first end attached to upper strap coupling 43 and a 
second end in a fixed loop 64 attached to the lower strap coupling 47. As 
previously mentioned, lower strap coupling 47 is comprised of detachable 
male and female elements. The first element of lower strap coupling 47 is 
attached to a loop in the strap. The second element of coupling 47 is 
fixed to the outer layer by being sewn to it or can be attached using 
velcro attachment. 
A waistband having a first end 70 and a second end 71 have on its surface 
complimentary velcro hook and loop to provide adjustability of the jacket 
10 circumference. When the waistband 70, 71 is unhooked so to speak, there 
is longitudinal stretch so as to provide flexibility within the jacket. 
As best seen in FIG. 2, adjustable wide waistbelt has a first end 70 and 
second end 72 fitted between outer and inner layers 52 and 53 
respectively. Referring now to FIG. 3, a more detailed view of the 
waistband arrangement is depicted. The first end 70 of the waistband is 
sewn to the central panel of jacket 10. Similarly, the second end 72 of 
the waistband is sewn to the central panel inside the layers of one of the 
wings. Either surface of the first or second end of the waistband may have 
the hook or loop material. The waistband may be made of double layered or 
flapped with velcro attachments on each of the individual layers to insure 
a tight fit. The waistband preferably comprises woven fabric webs having 
webs having neoprene strands in the stretch direction, and polyester and 
nylon strands in the transverse direction, the width typically being of 
several inches. This woven construction is permeable to the water, and 
therefor has little buoyancy, but more importantly has useful tension and 
stretch characteristics and no tendency to lose stretch upon use. A gator 
clamp 72 is provided for allowing adjustment of the waist band. In the 
preferred embodiment, the waistband has a longitudinal width of 
approximately four inches, but those skilled in the art will readily 
recognize that other widths may be more suitable for different sized 
jackets. 
Referring now to FIG. 4, a side sectional fragmentary view of the 
adjustable shoulder strap is illustrated. The shoulder strap is attached 
to the central panel at both top and bottom ends. A foam padding 74 is 
layered between an inner fabric 76 and an outer fabric 78. The upper 
coupling 43 is illustrated attached to the outer fabric 78 at the top end 
of the adjustable strap and includes a loop 80 for streamlining the 
strapping proces. The lower detachable male and female coupling 47 is 
illustrated attached also to the outer fabric 78. Stretchable material 82 
spans between the loop 80 for holding the strap and the male and female 
coupling 47. A span of non-stretchable strap 84 spans between the coupling 
47 and a pocket 86 for tucking in the loose end of the stretch strap. The 
pocket 86 is sewn to the outer fabric 78. 
Referring now to FIG. 5, the back view of the central panel is depicted to 
illustrate more detail. A hanger loop 90 is provided to hang the jacket 10 
for drying or storage purposes. Two layers of the center panel are sealed 
together at back lines 16 so that the entire panel may be blown up to 
provide balance buoyancy. 
As earlier mentioned, air tank or manual inflation may be maintained. Valve 
40 may be manually blown up from the mouth or from the tank and has a 
relief valve 41 (FIG. 1) for over pressure. 
Waist wings or extensions 91 and 92 are sewn to the to the center panel 
although they may be attached by velcro so as to be interchangeable. The 
interchangeability allows different color schemes to be attached to the 
jacket and to identify divers such as master or a novice diver. The fabric 
cover is sewn to the central panel around the edge at 93. 
Tank holder 28 is also shown in fragmentary form but does not include the 
cylindrical portion (shown in FIG. 6) matching the circumference of the 
tank 34. The tank holder 28 is approximately one-inch thick and is made of 
delrin, a type of plastic, but those skilled in the art will readily 
recognize that other materials and thicknesses may be used to hold the 
tank. 
Referring now to FIG. 6, slots 94 and 94' allow tank straps 34 and 36 to 
secure the tank to the plush pad 32. The straps are sewn to the plush pad 
32 and fit through slots 94 and 94'. A fabric cover 96 may be used to 
cover the rigid tank holder. Plush pad (back pad) 32 rests against the 
diver's back and tank straps 34 and 36 may have hinge coupling clamps for 
quick release of the tank. 
Reference is now made to FIG. 7 which depicts a second type of tank support 
arrangement. This is the preferred form of tank holder because the unit is 
completely soft and provides comfortability to the diver. Large hinges 96 
and 96' may be used for quick release of the tank in conjunction with 
straps and slots 37 and 37'. Structural foam 98 is inserted behind the air 
tank 38 and between the jacket and is removable and is ma be covered by 
fabric for protection. 
Referring now to FIG. 8 a fragmentary view of an alternative shoulder strap 
arrangement is depicted. A non-stretchable strap 102 is looped through an 
attachment ring 100 to a detachable male and female type coupler 104 on a 
first end. The detachable coupler 104 second end is attached to a 
stretchable strap which is adjustable and is secured by velcro on both 
sides with the use of small tabs to help secure the strap. 
The foregoing description of the preferred embodiment of the invention has 
been presented for the purposes of illustration and description. It is not 
intended to be exhaustive or to limit the invention to the precise form 
disclosed. Many modifications and variations are possible in light of the 
above teaching. It is intended that the scope of the invention be limited 
not by this detailed description, but rather by the claims appended 
hereto.