LOAD CARRYING SYSTEM Related Applications
[0001] This patent application relates to U.S. Provisional Application No. US60/598.155 filed on August 2, 2004 and claims the benefit of the earlier filing date under 35 U.S.C. 119(e). Technical Field
[0002] The present invention generally relates to load carrying systems and more specifically to backpacks, daypacks, mountaineering packs and other types of load carrying devices for carrying a load on a wearer's shoulders and hips, while engaging in various activities such as walking, hiking, mountaineering, skiing and the like. Background
[0003] A conventional load carrying system that is designed to carry a relatively heavy load distributes the weight of the load primarily between the wearer's shoulders and hips. This weight distribution is accomplished, in part, by providing an external or internal support frame structure, which carries the load within a pack or compartment attached to the outside surface of the frame. Typically, the weight of the load is supported on the wearer's shoulders by providing a pair of flexible and compressible shoulder straps, with an end of each strap attached respectively to opposite sides of the inside surface of the frame, usually at or below the top of the shoulders. The straps are designed to drape over the wearer's shoulders, and the other end of each strap is attached respectively to opposite, bottom portions of the frame. The weight of some of the load is also transferred to the wearer's hips by connecting opposite sides of the bottom of the frame to a flexible and compressible hip belt, fastened tightly around the wearer's hips and waist. Normally, the opposite sides of the bottom of the frame are attached to opposite sides of the hip belt such that the points of attachment are adjacent to the hipbone's iliac crest. The wearer is then able to adjust the load's weight distribution between the shoulders and hips by either lengthening or shortening the length of the shoulder straps. Shortening the straps transfers more of the load's weight to the wearer's shoulders, and lengthening the straps places more weight on the hips. In the conventional design, the weight of the load is primarily concentrated at the top of the shoulders and on the iliac crests due to the fact that the flexible and compressible
shoulder straps and hip belt do not have any substantial stiffness or rigidity and, thus, readily deform under the weight of the load.
[0004] Although the ability to distribute the weight of the load between the wearer's shoulders and hips provides a load carrying system design that is potentially more comfortable than a design that only carries the weight on the wearer's shoulders, stability of the load can become a problem if the load is particularly heavy and too much weight is distributed to the hips. In this instance, the load has a tendency to tip forward or backward and to sway from side-to-side, or to tip and sway simultaneously. Conventional systems attempt to address this stability problem by utilizing a pair of flexible tension straps, which are intended to partially stabilize the load. Typically, each tension strap is attached at one end to its respective shoulder strap, generally adjacent to the wearer's upper chest, at or just below the top of the wearer's shoulder, and the other end of each strap is attached to its respective portion of the backpack frame, at or just above the top of the shoulders. The tension straps are provided with an adjustable mechanism, which allows the wearer to adjust each strap's tension by either lengthening or shortening the strap. Shortening the tension strap increases the tension in the strap, while lengthening the strap decreases the tension. In order to maintain control over the movement of the load, however, the tension straps must be sufficiently tensioned in order to exert a tensile force equal to or greater than the forces that arise due to the tipping and swaying movements. Naturally, the heavier the load and/or the more violent the wearer's activities, the greater the tension must be on the tension straps to counter the forces which result from the tipping and swaying movements. [0005] Although the tension straps can be used by a wearer to partially control unwanted movements of the load, the amount of control is limited because the straps do not have any stiffness or rigidity and, as a result, have no strength in compression or resistance to bending. Thus, the tension straps are not able to control forward tipping motion and the straps are only partially able to control side-to-side swaying motion. In an attempt to gain more control over the swaying motion, the wearer will typically over- tension the tension straps, which increases the pressure of the shoulder straps on the wearer's chest and forces the wearer's middle back to press tightly against the inside surface of the support frame. As a result, the wearer experiences a general loss of
comfort and a loss of mobility in his or her spine, which is extremely detrimental when trying to maintain one's balance, especially when performing more challenging moves like jumping or skiing.
[0006] Another limitation in the ability of the tension straps to control the load exists due to the fact that the back portion of each shoulder strap is pulled away from the wearer's back when the tension straps are fully tensioned. This condition prevents any portion of the weight of the load to be transferred to the back of the shoulders and upper back. As a result, the back portion of each shoulder strap is rendered incapable of contributing to the desired control of unwanted movements of the load because this portion of each shoulder strap is no longer in contact with the wearer's body. [0007] Conventional systems, as noted above, also attempt to transfer a substantial portion of the load's weight to the wearer's hips. This is typically accomplished by connecting the frame and its load to the hip belt. The hip belt, which is typically made of a soft, padded material, is cinched tightly around the wearer's waist and hips in order to accept the weight of the load. However, due to hip belt's lack of rigidity, most of the load's weight is concentrated at the points where the frame is connected to the belt, and is transferred to corresponding points on the wearer's hips. Due to the concentration of the load at only two points on the wearer's hips, these points are prone to become tender and sore. In order to alleviate the soreness, a backpacker will typically take some of the weight of the load off of the hips by redistributing the weight to the shoulders by shortening the shoulder straps. Unfortunately, transferring some of the weight of the load to the shoulders causes the top of the shoulders to become more susceptible to becoming tender and sore because the shoulder straps' lack of stiffness or rigidity causes them to deform under the weight of the load, concentrating the weight on the top of the shoulders. The backpacker finds himself or herself in a never-ending struggle of redistributing the weight of the load between the hips and shoulders in an attempt to establish a comfortable position.
[0008] What is needed is a load carrying system that overcomes the limitations of the conventional systems by providing a more stable system which eliminates the need to increase the pressure on the wearer's chest and back in order to stabilize the load, and providing a more comfortable load carrying system which distributes the weight of the
load more uniformly on the wearer's shoulders, back and chest, rather than concentrating the weight primarily at the top of the shoulders, and by similarly distributing the weight of the load around the wearer's hips and waist, rather than primarily on the hipbone's iliac crest. Summary
[0009] A load carrying system for carrying a load on a wearer's body includes providing a frame configured to support the load, and a shoulder harness assembly having a harness panel and a harness pad. The harness panel is flexible and has inside and outside surfaces, with the outside surface attached to the frame. In one embodiment, the harness pad consists of three (3) integral layers: an outer layer and an inner layer, which are flexible, resilient, compressible and stretchable, and a middle layer which is flexible and resilient, with the outer layer having an outside surface. A plurality of elongate grooves is disposed within the outside surface of the harness pad's outer layer. The harness pad and the outside surface of the harness pad's outer layer are formed into a preferred curved shape, causing the width of the grooves to widen, and the inside surface of the harness panel is coupled to the outside surface of the harness pad's outer layer, whereby the coupling of the two surfaces substantially retains the curved shape of the harness pad. In one embodiment the inside surface of the harness panel and the outside surface of the harness pad's outer layer are releasably coupled by providing a hook and loop system in which a first coupling material is attached to the inside surface of the harness panel and a second coupling material is attached to the outside surface of the harness pad's outer layer and disposed between the grooves.
[0010] A waist belt assembly includes belt panel and a harness pad. The belt panel is flexible and has inside and outside surfaces, with the outside surface attached to the frame. In one embodiment, the belt pad consists of three (3) integral layers: an outer layer and an inner layer, which are flexible, resilient, compressible and stretchable, and a middle layer which is flexible, with the outer layer having an outside surface. A plurality of elongate grooves is disposed within the outside surface of the belt pad's outer layer. The belt pad and the outside surface of the belt pad's outer layer are formed into a preferred curved shape, causing the width of the grooves to widen, and
the inside surface of the belt panel is coupled to the outside surface of the belt pad's outer layer, whereby the coupling of the two surfaces substantially retains the curved shape of the belt pad. In one embodiment the inside surface of the belt panel and the outside surface of the belt pad's outer layer are releasably coupled by providing a hook and loop system in which a first coupling material is attached to the inside surface of the belt panel and a second coupling material is attached to the outside surface of the belt pad's outer layer and disposed between the grooves. Preferably, the outer and inner layers of both the harness pad and belt pad are made of closed cell foam and the middle layers are made of polyethylene and the elongate grooves have a cross-section that is v-shaped.
[0011] In another embodiment the shoulder harness assembly is modified by omitting its middle layer and utilizing a harness pad which has only two (2) layers: an outer layer and an inner layer which are flexible, resilient, compressible and stretchable. The waist belt assembly is similarly modified by omitting its middle layer and utilizing a belt pad which has only two (2) layers: an outer layer and an inner layer which are flexible, resilient, compressible and stretchable.
[0012] In another embodiment, the frame has an elongate, semi-rigid stabilizing member attached to the top of the end of the frame. The stabilizing member has a pair of left and right stabilizing member arms, extending outwardly and downwardly away from the frame and attached to the outside surface of the shoulder harness assembly's harness panel. In yet another embodiment the left and right stabilizing member arms are slideably connected to left and right friction sockets, respectively, with the friction sockets attached to the outside surface of the harness panel.
[0013] In another embodiment the outside surface of the shoulder harness assembly's harness panel is slideably attached to the frame so that the shoulder harness can be raised or lowered in relation to the frame, and in another embodiment the shoulder harness assembly is releasably attached to the frame so that the harness panel can be removed from the frame. In yet another embodiment the waist belt assembly's belt panel is pivotally attached to a bottom portion of the frame so that the frame can tilt forward or rearward in relation to the waist belt assembly. The amount the frame's tilt is controlled by an adjustable strap attached to opposite sides of the belt panel and
adjacent to the outside surface of the panel, shortening the strap limits the amount of the frame's potential rearward tilt and lengthening the strap increases the amount of the frame's potential rearward tilt.
Brief Description of the Drawings
[0014] FIG. 1 A is a front perspective view of the preferred embodiment of the load carrying system.
[0015] FIG. 1 B is a back perspective view of the preferred embodiment of the load carrying system.
[0016] FIG. 2A is a front perspective view of the preferred embodiment of the load carrying system with the pack removed from the frame.
[0017] FIG. 2B is a front perspective view of the shoulder harness assembly of the preferred embodiment, which has been removed from the frame.
[0018] FIG. 2C is a front perspective view of the shoulder harness assembly of the preferred embodiment separated into its two components: a harness panel and a harness pad.
[0019] FIG. 2D is a back perspective view of the shoulder harness assembly of the preferred embodiment separated into its two component parts: a harness panel and a harness pad.
[0020] FIG. 2E is an exploded view of the harness pad of the preferred embodiment illustrating the pad's three layers.
[0021] FIG.'S 3A through 3C are cross-sectional views of the harness panel and harness pad of the preferred embodiment.
[0022] FIG.'S 3D through 3F are cross-sectional views of the harness panel and harness pad in another embodiment.
[0023] FIG. 4A is a back perspective view of the preferred embodiment of the load carrying system illustrating the shoulder harness assembly in a raised position relative to the frame.
[0024] FIG. 4A-1 is detail illustration of a sliding frame assembly.
[0025] FIG. 4B is a back perspective view of the preferred embodiment of the load carrying system illustrating the shoulder harness assembly in a lowered position relative to the frame.
[0026] FIG. 4C is a pictorial diagram illustrating the shoulder harness assembly of the preferred embodiment in a low position relative to the frame (solid line), and further illustrating (in dashed lines) the shoulder harness assembly being raised to a higher position relative to the frame to the position illustrated in FIG. 4D.
[0027] FIG. 5A is a front perspective view of the preferred embodiment of the load carrying system illustrating a curved stabilizing member attached to the frame.
[0028] FIG. 5B is a front perspective view of the preferred embodiment of the load carrying system illustrating the curved stabilizing member in a position having increased curvature.
[0029] FIG. 6A is a plan view of the top of the preferred embodiment of the load carrying system illustrating the curved stabilizing member of FIG. 5A.
[0030] FIG. 6B is a plan view of the top of the preferred embodiment of the load carrying system illustrating the curved stabilizing member of FIG. 5B.
[0031] FIG. 7A is a front perspective view of the belt assembly of the preferred embodiment, which has been removed from the frame.
[0032] FIG. 7B is a front perspective view of the belt assembly of the preferred embodiment separated into its two component parts: a belt panel and a belt pad.
[0033] FIG. 7C is a back perspective view of the belt assembly of the preferred embodiment separated into its two component parts: a belt panel and a belt pad.
[0034] FIG. 7D is an exploded view of the belt pad of the preferred embodiment illustrating the pad's three layers.
[0035] FIG.'S 8A through 8C are cross-sectional views of the belt panel and belt pad of the preferred embodiment.
[0036] FIG.'S 8D through 8F are cross-sectional views of the belt panel and belt pad in another embodiment.
[0037] FIG. 9A is a back perspective view of the preferred embodiment of the load carrying system illustrating the position of the frame relative to the belt assembly in which the frame has the least amount of rearward tilt.
[0038] FIG. 9B is a back perspective view of the preferred embodiment of the load carrying system illustrating the position of the frame relative to the belt assembly in which the frame has the most amount of rearward lilt.
[0039] FIG. 10 is a pictorial diagram presenting a left side view of the frame, illustrating in a solid line the frame in a position having the least amount of rearward tilt and illustrating in a dashed line the frame in position having the most amount of rearward tilt.
Detailed Description of Preferred Embodiments
[0040] FIG.'s 1 A and 1B generally illustrate a preferred embodiment of a load carrying system 5, including a support frame 15 and a pack 10, with the pack 10 attached to the frame 15 for carrying a load in the pack 10 on a wearer's shoulders and hips. FIG. 2A illustrates the load carrying system 5 with the pack 10 removed from the frame 15. As used herein, the term "load carrying system" includes backpacks, daypacks, mountaineering packs, and other types of load carrying devices for carrying a load on the wearer's shoulders and hips. More specifically, one of the features of the load carrying system 5 includes a shoulder harness assembly 20, which is illustrated with reference to the following figures: the perspective drawing of FIG. 2A showing the shoulder harness assembly 20 attached to the frame 15; the perspective drawing of FIG. 2B illustrating the shoulder harness assembly 20 removed from the frame 15; the perspective drawings of FIG.'s 2C and 2D illustrating the shoulder harness assembly 20 in a disassembled condition; the exploded view of FIG. 2E illustrating the three (3) layers of a harness pad 30; and the pictorial representations of FIG.'s 3A through 3C presenting a partial cross-sectional view of the shoulder harness assembly 20. Specifically referring to FIG.'s 2A through 2D, the shoulder harness assembly 20 consists of a harness panel 25 and harness pad 30. The harness panel 25 consists of an integral back panel 35, having an inside and outside surfaces, 36 and 37, and pair of, left and right, integral yoke panels, 40 and 41, with each yoke panel having inside and outside surfaces, 42 and 43, and the pair of yoke panels, 40 and 41, disposed on opposite sides of and extending outwardly from the back panel 35 and terminating at a pair of yoke panel distal ends 45. And, as shown in FIG.'s 2C and 2D, and 3A through 3C, a first coupling material 80 of a hook and loop system is attached to the inside surface 36 of the back panel 35 and to the inside surface 42 of the pair of yoke panels 40 and 41. Preferably, the harness panel 25 has the physical properties of being relatively stiff, but also flexible and resilient. An acceptable material for the panel 25 is
high density polyethylene, having a thickness of approximately 1/16 of an inch or approximately 1.6 mm.
[0041] Referring to FIG.'s 2A and 2B, the harness pad 30 consists of an integral back pad 50 and a pair of left and right integral yoke pads 55 with the pair of yoke pads 55 disposed on opposite sides of and extending outwardly from the back pad 50 and terminating at a pair of yoke pad distal ends 60. And, as further illustrated in FIG.'s 2E, and 3A through 3C, the harness pad 30 is a laminated component consisting of three (3) integral and contiguous layers: an outer harness pad layer 65, having an outside surface 66, a middle harness pad layer 70, and an inner harness pad layer 75, having an inside surface 76. FIG. 2E is an exploded view of the harness pad 30, separately illustrating each harness pad layer 65, 70, and 75, and the cross sectional views of FIG.'s 3A through 3C further illustrate the harness pad 30 and integral and contiguous layers 65, 70, and 75. Each of the harness pad layers, 65, 70, and 75 consists of an integral back pad layer 50a, 50b, and 50c, respectively, and a pair of integral yoke pad layers 55a, 55b, and 55c, respectively, with the pair of yoke pad layers 55a, 55b, and 55c disposed on opposite sides of and extending outwardly from the back pad layers 50a, 50b, and 50c, respectively, and terminating at a pair of yoke pad distal ends 60a, 60b, and 60c, respectively. Back pad layer 50a has an outside surface 5Od, and the pair of yoke pad layers 55a has an outside surface 55d; and back pad layer 50c has an inside surface 5Oe and the pair of yoke pad layers 55c has an inside surface 55e.
[0042] The outer harness pad layer 65 and the inner harness pad layer 75 have the physical properties of exhibiting only minimal stiffness and of being flexible, resilient, compressible, and stretchable. Preferably the harness pad layers, 65 and 75, consist of closed cell foam made from olefin polymers or blends of olefin polymers. Generally, the preferred compressive strength and thickness of the foam layers are dependent upon the weight of the load being carried by the wearer. For lighter loads, which are typical of the loads carried in a daypack or small backpack, it is preferable to use foam for the inner harness pad layer 75 which has a relatively low compressive strength, because foam which is more compressible is generally more comfortable under load. However, using foam with a low compressive strength requires that the foam be thick enough in
order to ensure that the foam's full range of compression can be utilized. For heavier loads, which are typical of the loads carried in a large mountaineering pack, the compressive strength of the foam for the inner harness pad layer 75 can be approximately the same as that for carrying lighter loads, but the thickness of the foam can be somewhat greater in order to ensure that the heavier loads do not subject the foam to pressure in excess of its compressive limit. With respect to the foam for the outer harness pad layer 65, its preferred compressive strength and thickness are not as dependent upon the weight of the load, as is the case for the inner layer 75, because the outer layer 65 is not in contact with the wearer's body. As a result, for most load weights the preferred compressive strength of the foam for the outer layer 65 can generally range from foam having a relatively low compressive strength, similar to the compressive strength of the foam for the inner layer 75, up to foam having a compressive strength that is characterized as being almost incompressible, because it not necessary that the outer layer compress in order to ensure that the backpack is comfortable on the wearer's shoulders and upper torso. With respect to the thickness of the foam for the outer layer 65, the thickness for lighter loads can be similar to the thickness of the foam for the inner layer 75, but for heavier loads the thickness of the outer layer 65 can be less than the thickness of the inner layer 75, again due to the fact that the outer layer 65 of foam is not in contact with the wearer's body. [0043] More specifically, it is preferable that for loads of up to approximately five (5) lbs (2.3 kg) the thickness of the inner layer 75 is between approximately 1/8 and 3/4 of an inch, or approximately 3.2 and 19.0 mm, and the foam has a compressive strength of between approximately three (3) psi (0.21 kg/cm2) and five (5) psi (0.35 kg/cm2); for loads between approximately five (5) lbs (2.3 kg) and fifty (50) lbs (22.7 kg), the preferred thickness of the inner layer 75 is between approximately 3/16 and 3/4 of an inch, or approximately 4.7 and 19.0 mm, and the preferred compressive strength of the foam is between approximately four (4) psi (0.28 kg/cm2) and seven (7) psi (0.49 kg/cm2); and for loads between approximately fifty (50) lbs (22.7 kg) and approximately one-hundred (100) lbs (45.4 kg), the preferred thickness of the inner layer 75 is between approximately 3/16 and 7/8 of an inch, or approximately 4.7 and 22.2 mm, and the preferred compressive strength of the foam is between approximately five (5) psi (0.35
kg/cm2) and seven (7) psi (0.49 kg/cm2), ( all compressive strength values determined in accordance with ASTM International, Designation: D 3575-91 ). Examples of acceptable foams for the inner layer 75 are: Evazote® EV 30 for loads of up to fifty (50) lbs (22.7 kg), and Evazote® EV 50 for loads between fifty (50) lbs (22.7 kg) and one-hundred (100) lbs (45.4 kg). Concerning the outer layer 65, it is preferable that for loads of up to approximately twenty (20) lbs (9.1 kg) the thickness of the outer layer 65 is between approximately 1/8 and 1/2 of an inch, or approximately 3.2 and 12.7 mm, and the foam has a compressive strength of between seven (7) psi (0.49 kg/cm2) and fifteen (15) psi (1.05 kg/cm2); for loads between approximately twenty (20) lbs (9.1 kg) and fifty (50) lbs (22.7 kg) the preferred thickness of the outer layer 65 is between approximately 3/16 and 5/8 of an inch, or approximately 4.7 and 15.9 mm, and the compressive strength of the foam is between approximately nine (9) psi (0.63 kg/cm2) and seventeen (17) psi (1.19 kg/cm2); and for loads between approximately fifty (50) lbs (22.7 kg) and one- hundred (100) lbs (45.4 kg), the preferred thickness of the outer layer 65 is between approximately 3/16 and 3/4 of an inch, or approximately 4.7and 19.0 mm, and the compressive strength of the foam is between approximately twelve (12) psi (0.84 kg/cm2) and twenty (20) psi (1.40 kg/cm2), ( again, all compressive strength values determined in accordance with ASTM International, Designation: D 3575-91 ). Examples of acceptable foams for the outer layer 65 are: Plastazote® LD 15 for loads of up to five (5) lbs (2.3 kg), Plastazote® LD 45 for loads between five (5) lbs (2.3 kg) and fifty (50) lbs (22.7 kg), and Plastazote® LD 60 for loads between fifty (50) (22.7 kg) and one- hundred (100) lbs (45.4 kg).
[0044] Preferably, the middle harness pad layer 70 has a thickness which is substantially less than the thickness of the inner and outer harness pad layers, 65 and 75, and although the middle harness pad layer 70 is flexible and resilient, it also has the physical properties of being relatively stiff and non-stretchable as compared to the harness pad layers, 65 and 75. An acceptable material for the middle harness pad layer 70 is high density polyethylene, having a thickness of approximately 1/16 of an inch or approximately 1.6 mm. This layer provides some stiffness to the harness pad 30 without compromising the flexibility and compressibility of the outer layer 65 and inner layer 75.
[0045] Although specific types of materials and material thicknesses for the harness panel 25 and harness pad 30 have been described in connection with the preferred embodiment, it will be apparent to those skilled in the art that other types of materials and material thicknesses can also be used.
[0046] As shown in FIG.'s 2C, 2D, 2E, and 3A through 3C the outer harness pad layer 65 has a plurality of elongate yoke pad grooves 85, which form a yoke pad groove pattern within the outer layer's outside surface 66, and more specifically, each of the yoke pad grooves 85 are formed within the outside surface 55d of the pair of yoke pad layers 55a. Each of the yoke pad groves 85 extends widthwise across its respective yoke pad layer and is preferably spaced between approximately 1/2 and 1 1/2 inches (approximately 12.7 and 38.1 mm) apart. Preferably, each of the yoke pad grooves 85 has a depth which is between approximately 50% and 95% of the thickness of the pair of yoke pad layers 55a and each of the grooves 85 has a width at the outside surface 55d of its respective yoke pad layer which is approximately equal to the depth of the groove. Forming the yoke pad grooves 85 in this manner separates the outside surface 55d of the pair of yoke pad layers 55a into a pattern of yoke pad surface segments 90, disposed between the yoke pad grooves 85. Similarly, the outer harness pad layer 65 also has a plurality of elongate back pad grooves 86, which form a back pad groove pattern within the outer layer's outside surface 66, and more specifically, the back pad grooves 86 are formed within the outside surface 5Od of the back pad layer 50a. Each of the back pad grooves 86 extends widthwise across the back pad layer and is preferably spaced between approximately 1/2 and 1 1/2 inches (approximately 12.7 and 38.1 mm) apart. Again, it is preferable that each of the back pad grooves 86 has a depth which is between approximately 50% and 95% of the thickness of the back pad layer 50a and each of the grooves 86 has a width at the outside surface 5Od of the back pad layer 50a which is approximately equal to the depth of the groove. Similarly, forming the back pad grooves 86 in this manner separates the outside surface 5Od of the back pad layer 50a into a pattern of back pad surface segments 91, disposed between the back pad grooves 86. In a preferred embodiment, the elongate yoke pad grooves and back pad grooves, 85 and 86, as best illustrated in Fig. 3A, are "v-shaped" in that the grooves have a cross-sectional shape in the form of a "V" and each groove has an
approximately uniform width (w) as measured across the "V" at the outside surface of its respective pad. In addition to v-shaped grooves, other types of elongate openings having a cross-section in the form of a "U" or slit may be used as well. And, as shown in FIG.'s 2C through 2E, and 3A through 3C, a second coupling material 81 of the hook and loop system is attached to the plurality of yoke pad surface segments 90 and to the plurality of back pad surface segments 91.
[0047] The shoulder harness assembly 20 is assembled into a wearer's desired or predetermined curved shape, draped over the wearer's shoulders, by positioning the inside surface 76 of the inner harness pad layer 75 over the wearer's shoulders and bending the pair of yoke pads 55 down and adjacent to the wearer's chest, and bending the back pad 50 down and adjacent to the wearer's upper back. As illustrated in FIG. 3B, bending the yoke pads 55 and back pad 50 in this manner causes the outside surface 66 of the outer harness pad layer 65 to form a concave shape and causes the width (w) of the yoke pad grooves 85 and back pad grooves 86 to increase, and the inside surface 76 of the inner harness pad layer 75 forms a concave shape. Further, as illustrated in FIG. 3C, the desired curved shape is then substantially held in position by positioning the harness panel 25 adjacent to the harness pad 30 and mating or coupling the first coupling material 80 of the hook and loop fastening system, attached to the inside surface 36 of the back panel 35 and to the inside surface 42 of yoke panels 40 and 41 , to the second coupling material 81 of the hook and loop fastening system, attached to the plurality of yoke pad surface segments 90 and to the plurality of back pad surface segments 91. Assembling the shoulder harness assembly 20 in this manner creates a semi-rigid shoulder harness, which substantially retains its shape under load. In addition, the inside surface 76 of the inner harness pad layer 75, which is in contact with the wearer's body, is flexible and compressible, and the outside surface of the assembly, formed by the harness panel 25, is flexible and substantially incompressible. Once the wearer has assembled the harness panel 25 and harness pad 30 into a desired curved or predetermined shape, the wearer uses a yoke buckle mechanism 95, attached to the yoke panel distal ends 45 to further fasten the harness assembly 20 against the wearer's chest and upper back, and the wearer uses a pair of left and right frame attachment straps 46 and 47 to pivotally connect the shoulder
harness assembly 20 to left and right pivot plates, 301 and 302, respectively, which are attached to opposite, left and right sides of a belt assembly 200 (described below). [0048] The fact that the shoulder harness assembly 20 substantially retains its shape under load is a substantial improvement over conventional shoulder harnesses, because this feature of the harness assembly 20 causes the weight of the load to be substantially distributed over harness assembly's entire outside surface. Distributing the weight of the load 10 in this fashion substantially eliminates the pressure points at the top of the shoulders, which is a characteristic of conventional harnesses, made of soft and compressible pads and fabric. At the same time, the inside surface of the shoulder harness assembly 20, which is in contact with the wearer, is soft and compressible, ensuring that the shoulder harness 20 is comfortable. In addition to being more comfortable, harness assembly 20 significantly enhances stabilization of the load 10. When the shoulder harness assembly 20 is subjected to unwanted tipping and swaying forces from the wearer's load, the shoulder harness 20 absorbs the unwanted forces without any substantial deformity. Because the shoulder harness 20 holds its shape under load, the wearer's natural, reactive movements, which are made in attempt to counteract any tipping or swaying forces from the load, are instantly transmitted from the shoulder harness 20 to the frame 15, and then to the pack 10 containing the load. Another significant advantage of the shoulder harness 20 is that it does not have to be tightly cinched against the wearer's chest and back in order to obtain more control over the load. In conventional load carrying systems the wearer attempts to obtain more control over the load by shortening the shoulder straps, which presses the straps and frame closer to his or her body. Unfortunately, although the wearer may obtain more control over the load in this manner, the backpack is less comfortable due to the added pressure against his or her body. Another drawback arising from tightening the shoulder straps is that the straps tend to roll or slide forward and downward around the shoulders, which places additional stress on the top of the shoulders. The shoulder harness assembly 20 overcomes these limitations by providing the desired load control, thus eliminating the need to tightly cinch the harness 20 against the wearer's body. [0049] Referring to FIG.'s 4A through 4D, the frame 15 consists of an elongate frame panel 100, having a central frame panel 101 , with top and bottom edges, 102 and 103,
left and right side edges, 104 and 105, and inside and outside surfaces, 106 and 107. A pair of opposite, left and right, elongate side panels, 110 and 111, are attached to the central frame panel 101 by attaching the left side panel's top end 112 adjacent to the central panel's top and left side edges, 102 and 104, respectively, and attaching the left side panel's bottom end 113 adjacent to the central panel's bottom and left side edges, 103 and 104, respectively, thereby forming a left side panel opening 116. Similarly, the right side panel's top end 114 is attached adjacent to the central panel's top and right side edges, 102 and 105, respectively, and the right side panel's bottom end 115 is attached adjacent to the central panel's bottom and right side edges, 103 and 105, respectively, thereby forming a right side panel opening 117. Each side panel has a pair of opposite, left and right, integral panel arms, 118 and 119, which are joined at a pair of, left and right, opposite panel arm distal ends, 120 and 121 , respectively, thereby forming a bottom panel 122. The bottom panel 122 is positioned below the bottom edge 103 of the central panel 101 , thereby forming a central panel opening 123. The side panels, 110 and 111 , are attached to the central panel 101 , and the panel arm distal ends, 137 and 121, are joined such that the frame panel 100 forms a concave shape. An acceptable material for the central frame panel 101 is polycarbonate, having a thickness of approximately 2.0 mm, and an acceptable material for the side panels, 110 and 111, is compressed polypropylene fiber board, having a thickness of approximately 1.6 mm. A pair of opposite, left and right, elongate tubular side members, 125 and 126, are attached to the outside surfaces of the left and right side panels, 110 and 111 , respectively, and an elongate pipe bottom member 130, having a solid core, is attached to the outside surface of the bottom panel 122. The tubular side members, 125 and 126, and the pipe bottom member 130 contribute both to maintaining the concave shape of the frame panel 100 and to the overall strength of the panel 100. An acceptable material for the tubular side members, 125 and 126, is aluminum alloy tubing having outside and inside diameters of 0.35 inches (8.9 mm) and 0.29 inches (7.4 mm), respectively, and an acceptable material for the pipe bottom member 130 is a thermoplastic material having a diameter of 5/16 of an inch (7.9 mm). [0050] Another aspect of the load carrying system 5 is that the frame 15 is slideably attached to the shoulder harness assembly 20 such that the shoulder harness assembly
20 can be raised or lowered in relation to the frame 15, and the height of the shoulder harness assembly 20 can be adjusted while the shoulder harness assembly 20 is being worn by a wearer. As shown in FIG.'s 2D, 4A and 4B, the central frame panel 101 is provided with a vertical slot 131 which is positioned at the midline of the panel 101 and recessed within the outside surface of the panel 101. A pair of, left and right, vertical tabs, 132 and 133, integral with the central panel 101, are positioned adjacent to and below the slot 131, with each tab having a rectangular opening 134 through the tab. The vertical slot 131 contains a frame sliding assembly 135 consisting of a rectangular shaped sliding member 136 which is slideably disposed within the recessed portion of the vertical slot 131, said sliding member 136 having an elongate opening 137 and an integral horizontal member 138 extending across the elongate opening 137. The integral horizontal member 138 has a pair of opposite, left and right, ends, 139 and 140, with each end containing a vertical bore 141 (not shown). A hook-shaped member 143 is attached to the outside surface 37 of the shoulder harness panel's back panel 35 and is located at the midline of the back panel 35. The shoulder harness assembly 20 is adjustably attached to the frame 15 by attaching the hook-shaped member 143 to the frame sliding assembly 135, which is accomplished by passing the hook-shaped member 143 successively through the central frame panel's vertical slot 134 and the sliding member's elongate opening 134, and releasably engaging the hook-shaped member 143 with the sliding member's horizontal member 138. A looped portion of a shoulder harness adjustment cord 144 is disposed successively through: a clamping mechanism 145; a right stop member 146 attached to a right stabilizing member arm 156 (described below); and a hole 148 through the central frame panel 101, located adjacent to the central frame panel's top edge 102 and the right side edge 105. A non- looped portion of the cord 144 is disposed successively through: the rectangular opening 134 through the right tab 133; the bore 141 through the right end 140 of the horizontal member 138; the bore141 through the left end 139 of the horizontal member 138; the rectangular opening 134 through the left tab 132; a hole 149 through the central frame panel 101 , located adjacent to the central frame panel's top edge 102 and left side edge 104. The end of the looped portion of the adjustment cord 144 extends
out of the clamping mechanism 145 and the end of the non-looped portion of the cord 144 is attached to a left stabilizing member arm 155 (described below). [0051] A wearer adjusts the height of shoulder harness assembly 20 relative to the frame 15 by depressing a flange 147 extending out of the clasping mechanism 145, which allows the cord 135 to slide freely through the mechanism 145, and as a result, allows the shoulder harness assembly to be either raised or lowered. When the desired position is attained, the clasping mechanism 145 is positioned adjacent to the stop mechanism 146 and the flange 147 is released, causing the clamping mechanism 145 to clamp onto the cord 144 and maintain the position of the shoulder mechanism 20 relative to the frame 15. FIG. 4A shows the shoulder harness assembly 20 in a high position relative to the frame 15, with the end of the looped portion of the cord 144 adjacent to the left stop member 146, and FIG. 4B shows the shoulder harness assembly 20 in a low position relative to the frame 15, with the end of the looped portion of the cord 144 pulled away from the left stop member 146 in the direction of the "arrow". The pictorial diagram presented in FIG. 4C shows the shoulder harness assembly 20 in the low position relative to the frame 15, and the "arrow" in FIG.4C illustrates the direction the shoulder harness assembly 20 moves when it is raised to the high position, as shown in FIG. 4D. Another feature of the frame attachment is that the shoulder harness assembly 20 can be easily removed from the frame 15, which facilitates the assembly of the shoulder harness assembly 20 into a preferred curved shape. Removing the shoulder harness 20 from the frame 15 is accomplished by simply disengaging the hook-shaped member 143 from the frame sliding assembly 135, which allow the shoulder harness assembly 20 to be separated from the frame 15. [0052] The frame 15 is further provided with a pack attachment strap 124, which is positioned adjacent to the top edge 102 of the frame's central panel 101. The strap 124 extends circumferentially around the panel 101 and is fastened tightly against the panel's outside surface 107 by passing one end of the strap through a buckle loop attached to the strap's other end, and a first hook and loop coupling material, attached to the inside surface of the strap 124, is mated to a second hook and loop coupling material, attached to the outside surface of the strap 124. The pack 10 is provided with a semi-rigid pack flange (not shown) which is adjacent to the top and back side the pack
10 and extends downwardly from the top of the pack 10. The pack 10 is attached to frame 15 by passing the pack flange between the outside surface 107 of the central panel and the pack attachment strap 124.
[0053] Although the shoulder harness assembly 20 provides a load carrying system with enhanced stability and is still comfortable, in some applications where heavier loads are being carried, additional stability might be desired. In those instances, another feature of the load carrying system can be used to further stabilize the load. As illustrated in FIG.'s 5A, 5B, 6A, and 6B, an elongate pipe stabilizing member 150, having a solid core, is attached to the inside surface 106 of the central frame panel 101 and generally adjacent to its top edge 102, and a pair of opposite, left and right, stabilizing member arms 155 and 156, respectively, extend outwardly and downwardly from the inside surface of the central frame panel 101. Due to the slight curvature of the central frame panel's top edge 102, the stabilizing member 150 is similarly curved when it is attached to the central frame panel 101. The stabilizing member 150 is a relatively stiff member, but it has sufficient flexibility to flex or bend in response to forces which are to be reasonably expected while carrying loads of up to approximately 100 lbs (45.4 kg). An acceptable material is acetal copolymer solid core pipe having a diameter of 3/8 of an inch (9.5 mm) and a flexural strength of between approximately 85 and 100 MPa. [0054] The stabilizing member 150 is adjustably attached to the shoulder harness assembly 20 by passing the left stabilizing member arm 155 through a friction socket 160 attached to the outside surface 43 of the left side yoke panel 40 and passing the right stabilizing member arm 156 through another friction socket 161 attached to the outside surface 43 of the right side yoke panel 41. Each of the stabilizing member arms, 155 and 156, has a series of circular groves 162, which extend axially along the length of the respective stabilizing member arm, and each friction socket, 160 and 161 , has an internal engagement mechanism which is activated by the operation of a pin 163 extending out of the socket. When the pins are depressed the stabilizing member ends can freely slide through the sockets, and when the pins are released the engagement mechanisms within each friction socket engage the grooves along the stabilizing member arms, preventing further movement of the stabilizing members. By successively depressing each pin and either pulling or pushing on the respective
stabilizing member arm, the wearer is able to adjust both the distance between the shoulder harness assembly 20 and the frame 15 and the curvature of the stabilizing member 150. As specifically illustrated in FIG. 6A, when stabilizing member arms, 155 and 156, are pulled in the direction of the "arrow" through friction sockets, 160 and 161, the distance between the outside surface 37 of shoulder harness assembly's back panel 35 and the frame 15 is reduced, which enhances the stability of the load by bringing the load closer to the wearer's back. At the same time, the distance between the inside surface 5Oe of the assembly's back pad layer 50c and the inside surface 55e of the pair of yoke pad layers 55c decreases, which brings the shoulder harness assembly 20 into tighter and closer contact with the wearer's chest, shoulders and back, giving the wearer even more control over the load. In this regard, maximum stability over the load is achieved by pulling the stabilizing member arms, 155 and 156, through the friction sockets, 160 and 161 , as far as possible. The enhanced stability increases the effectiveness of the wearer's control over the load by further ensuring that the wearer's reactions to unexpected movements of the load are efficiently transferred from the shoulder harness assembly 20 to the frame 15 and then to the load. Although this configuration certainly provides the most stability, some wearer's may find that they would prefer a more comfortable experience. In that case, as shown in FIG. 6B, the wearer can adjust the configuration of shoulder harness assembly 20 and its proximity to the frame 15 by pushing the stabilizing member ends through the friction sockets in the direction of the "arrow", which increases the distance between the shoulder harness assembly and the frame and loosens the contact between the shoulder harness assembly 20 and the wearer's body.
[0055] In addition to using the stabilizing member 150 to adjust the configuration and position of the shoulder harness assembly, the fact that the stabilizing member 150 resists bending further contributes to the stability of the load and represents a significant improvement over conventional tension straps. Conventional load carrying systems typically attempt to stabilize the load, in part, by utilizing fabric tension straps, extending between the shoulder straps and the frame. When the straps are tensioned they resist the load's rearward tipping motion and partially resist side-to-side swaying motions. However, since the straps have no intrinsic stiffness, the swaying motions are resisted
only by fully tensing the straps, which pulls the frame closer to the wearer's back. The strap's lack of stiffness also prevents them from resisting any forward tipping motions. The stabilizing member 150 of the load carrying system 5, on the other hand, resists all of these unwanted motions because the member 150 has sufficient stiffness to substantially retain its shape under load. The stabilizing member 150 instantly and positively transfers the wearer's natural, reactive movements, made in an attempt to counteract tipping or swaying forces caused by the load.
[0056] In another embodiment of the load carrying system 5, as shown in FIG.'s 3D through 3F, the shoulder harness assembly 20 is modified slightly by omitting the middle layer and utilizing a harness pad 30a that has only two (2) layers: an outer layer 65a and an inner layer 75a. Otherwise the harness pad components of the two (2) layer embodiment utilize the same harness pad components as the three (3) layer embodiment. The outer layer 65a and inner layer 75a of the two (2) layer embodiment have the same shape and physical properties as the outer layer 65 and inner layer 75, respectively, of the preferred three (3) layer embodiment. And, the selection of foam having a specific compressive strength and thickness is generally dictated by the same considerations that were discussed in connection with the three (3) layer embodiment of the harness pad 30. However, due to the fact that there is no middle layer to provide some additional stiffness to the harness pad, the stiffness must be supplied by the two layers themselves. As a result, although the thickness of the foam used in two (2) layer embodiment is generally the same as the thickness of the foam utilized in the three (3) layer embodiment, the preferred compressive strength of the foam used in the two (2) layer embodiment is generally greater than the compressive strength of the foam utilized in the three (3) layer embodiment.
[0057] Specifically, for loads of up to approximately five (5) lbs (2.3 kg) the preferred thickness of the inner layer 75a for the two (2) layer embodiment is between approximately 1/8 and 3/4 of an inch, or approximately 3.2 and 19.0 mm, and the preferred compressive strength of the foam is between approximately four (4) psi (0.28 kg/cm2) and seven (7) psi (0.49 kg/cm2); and for loads between approximately five (5) lbs (2.3 kg) and twenty (20) lbs (9.1 kg) the preferred thickness of the inner layer 75a is between approximately 3/16 and 3/4 of an inch, or approximately 4.7 and 19.0 mm,
and the preferred compressive strength of the foam is between approximately five (5) psi (0.35 kg/cm2) and eight (8) psi (0.56 kg/cm2). An example of acceptable foam for the inner layer 75a is Evazote® EV 30 for loads of up to twenty (20) lbs (9.1 kg). With respect to the outer layer 65a for the two (2) layer embodiment, for loads of up to approximately twenty (20) lbs (9.1 kg) the preferred thickness of the outer layer 65a is between approximately 1/8 and 1/2 of an inch, or approximately 3.2 and 12.7 mm, and the preferred compressive strength of the foam is between approximately seven (7) psi (0.49 kg/cm2) and eighty-six (86) psi (6.02 kg/cm2). An example of acceptable foam for the outer layer 65a is Evazote® LD 45.
[0058] The harness pad outer layer 65a of the two (2) layer embodiment also contains the same v-shaped groove pattern, including the width, depth and spacing of the grooves, the same pattern of pad segments between the grooves, and the same coupling materials of the hook and loop system as in the harness pad 30 of three (3) layer embodiment. The two (2) layer embodiment also uses the same harness panel 25 that is utilized in the three (3) layer embodiment, and the harness pad 30a and harness panel 25 are assembled and attached to the frame 15 in the same manner as the harness pad 30 and the harness panel 25. Further, the two (2) layer embodiment has the same advantages over conventional load carrying systems as the three (3) layer embodiment.
[0059] Another feature of the load carrying system 5 includes a waist belt assembly 200, which is illustrated with reference to the following figures: the perspective drawing of FIG. 2A illustrating a waist belt assembly 200 attached to the frame 15; the perspective drawing of FIG. 7A illustrating the belt assembly 200 removed from the frame 15; the perspective drawings of FIG.'s 7B and 7C illustrating the belt assembly 200 in a disassembled condition; the exploded view of FIG. 7D illustrating the three (3) component parts of the belt pad 205; and the pictorial representations of FIG.'s 8A through 8C presenting a partial cross-sectional view of the belt assembly 200. Specifically referring to FIG.'s 7A through 7D, the waist belt assembly 200 consists of a belt panel 205 and a belt pad 210. The belt panel 205 consists of an integral lumbar panel 215, having inside and outside surfaces, 216 and 217, and a pair of integral, left and right, hip panels, 220 and 221, with each hip panel having inside and outside
surfaces, 222 and 223, and the pair of hip panels, 220 and 221, disposed on opposite sides of and extending outwardly from the lumbar panel 215, and terminating at a pair of hip panel distal ends 225. And, as shown in FIG.'s 7B, 7C, and 8A through 8C, a first coupling material 275 of a hook and loop system is attached to the inside surface 216 of the lumbar panel 205 and to the inside surface 222 of the pair of hip panels 220 and 221. Preferably, the belt panel 205 has the physical properties of being relatively stiff, but also flexible and resilient. An acceptable material for the panel 205 is high density polyethylene, having a thickness of approximately one-sixteenth (1/16) of an inch or approximately 1.6 mm.
[0060] The belt pad 210 consists of an integral lumbar pad 230 and a pair of integral hip pads 235, with the pair of hip pads 235 disposed on opposite sides of and extending outwardly from the lumbar pad 230 and terminating at a pair of hip pad distal ends 240. And, as further illustrated in FIG.'s 7D, and 8A through 8C, the belt pad 210 is a laminated component consisting of three (3) integral and contiguous layers: an outer belt pad layer 245 having an outside surface 246, a middle belt pad layer 250, and an inner belt pad layer 255, having an inside surface 256. FIG. 7D is an exploded view of the belt pad 210, illustrating the belt pad layers 245, 250, and 255, and the cross sectional views of FIG.'s 8A through 8C further illustrate the belt pad 210 and integral and contiguous layers 245, 250, and 255. Each of the belt pad layers, 245, 250, and 255, consists of an integral lumbar pad layer 230a, 230b, and 230c, respectively, and a pair of integral hip pad layers 235a, 235b, and 235c, respectively, with the pair of hip pad layers 235a, 235b, and 235c disposed on opposite sides of and extending outwardly from the lumbar pad layers 230a, 230b, and 230c, respectively, and terminating at a pair of hip pad distal ends 240a, 240b, and 240c, respectively. Lumbar pad layer 230a has an outside surface 23Od and the pair of hip pads layers 235a has an outside surface 235d.
[0061] The outer belt pad layer 245 and the inner belt pad layer 255 have the same general physical properties as those of the inner and outer harness pad layers in that the inner and outer hip pad layers, 245 and 255, have the physical properties of exhibiting only minimal stiffness and of being flexible, resilient and compressible, and preferably consist of closed cell foam made from olefin polymers or blends of olefin
polymers. Further, as in the harness pad foam layers, the preferred compressive strength and thickness of the belt pad foam layers are generally dependent upon the weight of the load being carried by the wearer. For lighter loads, which are typical of the loads carried in a small daypack, it is preferable to use foam for the inner belt pad layer 255 which has a relatively low compressive strength, because foam which is more compressible is generally more comfortable under load. However, using foam with a low compressive strength requires that the foam be thick enough in order to ensure that the foam's full range of compression can be utilized. For heavier loads, which are typical of the loads carried in a large expedition backpack, the compressive strength of the foam for the inner belt pad layer 255 can be approximately the same as that for carrying lighter loads, but the thickness of the foam can be somewhat greater in order to ensure that the heavier loads do not subject the foam to pressure in excess of its compressive limit. Concerning the foam for the outer belt pad layer 245, its preferred compressive strength and thickness are not as dependent upon the weight of the load, as is the case for the inner belt pad layer 255, because the outer layer 245 is not in contact with the wearer's body. As a result, for most load weights the preferred compressive strength of the foam for the outer layer 245 can generally range from foam having a relatively low compressive strength, similar to the compressive strength of the foam for the inner layer 255, up to foam having a compressive strength that is characterized as being almost incompressible, because it not necessary that the outer layer compress in order to ensure that the backpack is comfortable on the wearer's waist and hips. With respect to the thickness of the foam for the outer layer 245, the thickness for lighter loads can be similar to the thickness of the foam for the inner layer 255, but for heavier loads the thickness of the outer layer 245 can be less than the thickness of the inner layer 255, again due to the fact that the outer layer 245 of foam is not in contact with the wearer's body.
[0062] More specifically, it is preferable that for loads of up to approximately five (5) lbs (2.3 kg) the thickness of the inner belt pad layer 255 is between approximately 1/8 and 3/4 of an inch, or approximately 3.2 and 19.0 mm, and the foam has a compressive strength of between approximately three (3) psi (0.21 kg/cm2) and five (5) psi (0.35 kg/cm2); for loads between approximately five (5) lbs (2.3 kg) and fifty (50) lbs (22.7),
the preferred thickness of the inner belt pad layer 255 is between approximately 3/16 of an inch and 1 inch, or approximately 4.7 and 25.4 mm, and the preferred compressive strength of the foam is between approximately four (4) psi (0.28 kg/cm2) and seven (7) psi (0.49 kg/cm2); and for loads between approximately fifty (50) lbs (22.7 kg) and approximately one-hundred (100) lbs. (45.4 kg), the preferred thickness of the inner belt pad layer 255 is between approximately 1/4 of and inch and 1 1/2 inches, or approximately 6.4 and 38.1 mm, and the preferred compressive strength of the foam is between approximately five (5) psi (0.35 kg/cm2) and seven (7) psi (0.49 kg/cm2), (all compressive strength values determined in accordance with ASTM International, Designation: D 3575-91 ). Examples of acceptable foams for the inner belt pad layer 255 are: Evazote® EV 30 for loads of up to fifty (50) lbs (22.7 kg), and Evazote® EV 50 for loads between fifty (50) lbs (22.7 kg) and one-hundred (100) lbs (45.4 kg). With respect to the specifications for the outer layer 245, it is preferable that for loads of up to approximately five (5) lbs (2.3 kg) the thickness of the outer layer 245 is between approximately 1/8 and 1/2 of an inch, or approximately 3.2 and 12.7 mm, and the foam has a compressive strength of between approximately six (6) psi (0.42 kg/cm2) and twelve (12) psi (0.84 kg/cm2); for loads between approximately five (5) lbs (2.3 kg) and fifty (50) lbs (22.7 kg) the preferred thickness of the outer layer 245 is between approximately 3/16 and 3/4 of an inch, or approximately 4.7 and 19.0 mm, and the compressive strength of the foam is between approximately seven (7) lbs (0.49 kg/cm2) and seventeen (17) psi (1.19 kg/cm2); and for loads between approximately fifty (50) lbs (22.7 kg) and one-hundred (100) lbs (45.4 kg)., the preferred thickness of the outer layer 245 is between approximately 3/16 and 7/8 of an inch, or approximately 4.7 and 22.2 mm, and the compressive strength of the foam is between twelve (12) psi (0.84 kg/cm2) and twenty (20) psi (1.40 kg/cm2), ( again, all compressive strength values determined in accordance with ASTM International, Designation: D 3575-91 ). Examples of acceptable foams for the outer layer 245 are: Plastazote® LD 33 for loads of up to twenty (20) lbs (9.1 kg); and Plastazote® LD 45 for loads between twenty (20) lbs (9.1 kg) and one-hundred (100) lbs (45.4 kg).
[0063] Preferably, the middle belt pad layer 250 has a thickness which is substantially less than the thickness of the inner and outer belt pad layers, 245 and 2555, and
although the middle belt pad layer 250 is flexible and resilient, it also has the physical properties of being relatively stiff and non-stretchable as compared to the belt pad layers, 65 and 75. An acceptable material for the middle belt pad layer 250 is high density polyethylene, having a thickness of approximately 1/16 of an inch, or approximately 1.6 mm. This layer provides some stiffness to the belt pad 210 without compromising the flexibility and compressibility of the outer layer 245 and inner layer 255.
[0064] Although specific types of materials and material thicknesses for the belt panel 205 and the belt pad 210 have been described in connection with the preferred embodiment, it will be apparent to those skilled in the art that other types of materials and material thicknesses can also be used.
[0065] Further, as shown in FIG.'s 7B, 7C, and 7D, the outer belt pad layer 245 has a plurality of elongate hip pad grooves 260, which form a hip pad groove pattern within the outer layer's outside surface 246, and more specifically, the hip pad grooves 260 are formed within the outside surface 235d of the pair of hip pad layers 235a. Each of the hip pad grooves 260 extends widthwise across its respective the hip pad layer and is preferably spaced between approximately 1/2 and 1 1/2 inches, or approximately 12.7 and 38.1 mm, apart. Preferably, each hip pad groove 260 has a depth which is between approximately 50% and 95% of the thickness of the pair of hip pad layers 235a and each groove 260 has a width at the outside surface of its respective hip pad layer which is approximately equal to the depth of the groove. Forming the hip pad grooves in this manner separates the outside surfaces of the pair of hip pad layers 235a into a pattern of hip pad surface segments 280, disposed between the hip pad grooves 260. Similarly, the outer belt pad layer 245 also has a plurality of elongate lumbar pad grooves 265, which form a lumbar pad groove pattern within the outer layer's outside surface 246, and more specifically, the lumbar pad grooves 265 are formed within the outside surface 23Od of the lumbar pad layer 230a. Each of the lumbar pad grooves 265 extends widthwise across the lumbar pad layer and is preferably spaced between approximately 1/2 and 1 1/2 inches, approximately 12.7 and 38.1 mm, apart. Again, it is preferable that each lumbar pad groove 265 has a depth which is between approximately 50% and 95% of the thickness of the lumbar pad layer 230a and each
groove 265 has a width at the outside surface of the lumbar pad layer which is approximately equal to the depth of the groove. Forming the lumbar pad grooves 265 in this manner separates the outside surface of the lumbar pad layer 230a into a pattern of lumbar pad surface segments 281 , disposed between the lumbar pad grooves 265. In a preferred embodiment, the elongate hip pad grooves and lumbar pad grooves, 260 and 265, as best illustrated in Fig. 8A, are "v-shaped" in that the grooves have a cross- sectional shape in the form of a "V" and each groove has an approximately uniform width (w) as measured across the "V" at the outside surface of its respective pad. In addition to v-shaped grooves, other types of elongate openings having a cross-section in the form of a "U" or slit may be used as well. And, as shown in FIG.'s 7B through 7D, and 8A through 8C, a second coupling material 276 of a hook and loop system is attached to the plurality of hip pad surface segments 280 and to the plurality of lumbar pad surface segments 281.
[0066] In the preferred embodiment, as illustrated in FIG.'s 9A, 9B, 10A, and 10B, the belt assembly 200 is pivotally connected to the frame 15. This pivotal connection is provided by attaching a bottom portion of the frame's left side tubular side member 105 to a left pivot plate 301 , pivotally attached at pivot point 303 to the outside surface 223 of the left side hip panel 220, and similarly attaching a bottom portion of the right side tubular side member 106 to a right pivot plate 302, pivotally attached at pivot point 304 to the outside surface 223 of the right side hip panel 221. Each of the pivot plates, 301 and 302 has an elongate slot, 310 and 320, respectively, which is positioned within its respective plate such that when the frame is in an approximately vertical position and the waist belt assembly is in an approximately horizontal position, each slot is below its respective pivot point. The frame 15 is also provided with an adjustable pivot control feature, which controls how far the frame 15 can pivot or tilt in a rearward direction in response to a rearward motion of the load. Referring to FIG. 9A, this feature is implemented by attaching an adjustable lumbar strap 305 to the frame 15 and to the outside surface 217 of the lumbar panel 215. More specifically, the lumbar strap 305, having inside and outside surfaces, 306 and 307, and left and right ends 308 and 309, is disposed successively through: the slot 310 within the left pivot plate 301, a loop 315 attached to the outside surface 217 of the lumbar panel 215, and another slot 320 within
the right pivot plate 302. The lumbar strap's left and right ends, 308 and 309, extend out of slots 310 and 320, respectively. Left side and right side first coupling materials 325 and 326, of a hook and loop system are attached to the outside surface 307 of the lumbar strap 305, with the left coupling material 325 located adjacent to the lumbar strap's left end 308 and the right coupling material 326 adjacent to the lumbar strap's right end 309. Left side and right side second coupling materials 330 and 331, of the hook and loop system are also attached to the outside surface 307 of the lumbar strap 305, with the left coupling material 330 located generally between the slot 310 within the left pivot plate 301 and the loop 315 attached to the lumbar panel's outside surface 217, and the right coupling material 331 located generally between the slot 320 within the right pivot plate 302 and the loop 315. In operation a wearer of the load carrying system 5 is able to limit the amount of the frame's reward tilt by mating the hook and loop system's left side first coupling material 325 to the left side second coupling material 330 and similarly mating the right side first coupling material 326 to the right side second coupling material 331. Mating the hook and loop materials in this manner has the effect of fixing the length of the lumbar strap 305 between pivot plate slots, 310 and 320, which in turn acts to restrain the rearward tilt of the frame 15. The amount of rearward tilt is then adjusted simply by adjusting the length of the lumbar strap 305 between the slots, 310 and 320, lengthening the lumbar strap increases the reward tilt and shortening the lumbar strap reduces it.
[0067] The pictorial diagram presented in FIG. 10 further illustrates the adjustable, frame tilting feature. The figure presents a left side view of the frame 15 (drawn in a solid line), illustrating the frame 15 pivoting around the pivot points, 303 and 304 and in a position with the least amount of reward tilt, and illustrating the frame 15 (drawn in dashed lines) again pivoting around the pivot points, 303 and 304, and in a position with the maximum amount of reward tilt. Between these two extreme frame positions, the wearer can control the desired amount frame tilt by using the strap 305 as described above.
[0068] The wearer forms the belt assembly 200 into a desired or preferred curved shape by positioning the inner belt pad layer 255 adjacent to the wearer's hips and waist, and bending the belt pad 210 around the wearer's hips and waist by bringing one
of the hip pad distal ends 240 towards the other distal end 240. As illustrated in FIG. 8B, bending the belt pad 210 in this manner causes the hip pad grooves 260 to widen. And, as illustrated in FIG. 8C, the belt assembly's preferred shape is then substantially held in position by positioning the belt panel 205 adjacent to the belt pad 210 and mating the first coupling material of the hook and loop system 275 attached to the inside surface of the belt panel 205 to the second coupling material of the hook and loop system 276 attached to the plurality of hip pad surface segments 280 and to the plurality of lumbar pad surface segments 281. Assembling the belt panel 205 and belt pad 210 in this fashion creates belt assembly 200 having sufficient stiffness to hold its shape under load. Once the wearer has assembled the belt panel 205 and belt pad 210 into a preferred curved shape, the wearer uses a conventional buckle mechanism 270, attached to the hip panel distal ends 220 and 221 , to further fasten the belt assembly 200 around the wearer's hips and waist. The belt assembly 200 is a substantial improvement over conventional backpack belts because the stiffness of the belt assembly causes the weight of the load to be distributed around the entire outside surface of the belt. Distributing the weight of the load in this fashion eliminates the pressure points, where the frame is connected to the belt, which is a characteristic of conventional load carrying systems made of flexible and compressible pads and fabric. At the same time, the inside surface of the belt assembly 200, in contact with the wearer, is compressible, ensuring that the belt is comfortable. [0069] In another embodiment of the load carrying system 5, as shown in FIG.'s 8D through 8F, the waist belt assembly 200 is modified slightly by omitting the middle layer 250 and utilizing a belt pad 210a that has only two (2) layers: an outer layer 245a and an inner layer 255a. Otherwise the belt pad components of the two (2) layer embodiment utilize the same belt pad components as the three (3) layer embodiment. The outer layer 245a and inner layer 255a, as in the three (3) layer embodiment, consist of flexible and compressible closed cell foam made from olefin polymers. And, the selection of foam having a specific compressive strength and thickness is generally dictated by the same considerations that were discussed in connection with the three (3) layer embodiment of the belt pad 210. However, due to the fact that the middle layer has been omitted, the extra stiffness supplied by the middle layer in the three layer
embodiment must be supplied by the two layers themselves. As a result, the preferred compressive strength of the foam used in the two (2) layer embodiment is generally greater than the compressive strength of the foam utilized in the three (3) layer embodiment, and the thickness of the foam used in two (2) layer embodiment is generally greater than the thickness of the foam utilized in the three (3) layer embodiment.
[0070] Specifically, for loads of up to approximately five (5) lbs (2.3 kg) the preferred thickness of the inner layer 255a for the two (2) layer embodiment is between approximately 1/8 and 3/4 of an inch, or approximately 3.2 and 19.0 mm, and the preferred compressive strength of the foam is between approximately four (4) psi (0.28 kg/cm2) and seven (7) psi (0.49 kg/cm2); and for loads between five (5) lbs (2.3 kg) and twenty (20) lbs (9.1 kg) the preferred thickness of the inner layer 255a is between approximately 3/16 of an inch and 1 inch, or approximately 4.7 and 25.4 mm, and the preferred compressive strength of the foam is between approximately five (5) psi (0.35 kg/cm2) and eight (8) psi (0.56 kg/cm2). An Example of acceptable foam for the inner layer 75a is Evazote® EV 30 for loads of up to twenty (20) lbs (9.1 kg). With respect to the outer layer 245a for the two (2) layer embodiment, for loads of up to approximately five (5) lbs (2.3 kg) the preferred thickness of the outer layer 245a is between approximately 1/8 and 3/4 of an inch, or approximately 3.2 and 19.0 mm, and the preferred compressive strength of the foam is between approximately seven (7) psi (0.49 kg/cm2) and eighty-six (86) psi (6.02 kg/cm2); and for loads of between approximately five (5) lbs (2.3 kg) and twenty (20) lbs (9.1 kg) the preferred thickness of the outer layer 245a is between approximately 3/16 and 3/4 of an inch, or approximately 4.7 and 19.0 mm, and the preferred compressive strength of the foam is between approximately nine (9) lbs (0.63 kg/cm2) and eighty-six (86) psi (6.02 kg/cm2). Examples of acceptable foams for the outer layer 245a are: Plastazote® LD 24 for loads of up to five (5) lbs (2.3 kg), and Plastazote® LD 45 for loads between five (5) lbs (2.3 kg) and twenty (20) lbs (9.1 kg).
[0071] The belt pad outer layer 245a of the two (2) layer embodiment contains the same v-shaped groove pattern, including the width, depth and spacing of the grooves, the same pattern of pad segments between the grooves, and the same coupling
materials of the hook and loop system as in the belt pad 210 of three (3) layer embodiment. The two (2) layer embodiment also uses the same belt panel 205 that is utilized in the three (3) layer embodiment, and the belt pad 210a and belt panel 205 are assembled and attached to the frame 15 in the same manner as the belt pad 210 and the belt panel 215. Further, the two (2) layer embodiment has the same advantages over convention load carrying systems as the three (3) layer embodiment. [0072] Although the load carrying system has been described in its preferred embodiment and in certain other embodiments, it will be recognized by those skilled in the art that other embodiments and features may be provided without departing from the underlying principals of those embodiments. The scope of the invention is defined only by the appended claims.