Patent Application
20070251965
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Referring to
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.
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 ⅛ and ¾ 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 ¾ 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 ⅞ 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 ⅛ and ½ 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 ⅝ 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 ¾ of an inch, or approximately 4.7 and 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).
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.
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.
As shown in
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
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.
Referring to
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
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.
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.
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
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
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.
In another embodiment of the load carrying system 5, as shown in
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 ⅛ and ¾ 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 ¾ 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 ⅛ and ½ 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.
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.
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
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
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.
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 ⅛ and ¾ 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 ¼ of and inch and 1½ 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 ⅛ and ½ 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 ¾ 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 ⅞ 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).
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.
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.
Further, as shown in
In the preferred embodiment, as illustrated in
The pictorial diagram presented in
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
In another embodiment of the load carrying system 5, as shown in
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 ⅛ and ¾ 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 ⅛ and ¾ 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 ¾ 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).
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.
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.
This patent application relates to U.S. Provisional Application No. US60/598,155 filed on Aug. 2, 2004 and claims the benefit of the earlier filing date under 35 U.S.C. 119(e).
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US05/27454 | 8/2/2005 | WO | 2/2/2007 |
| Number | Date | Country | |
|---|---|---|---|
| 60598155 | Aug 2004 | US |
