Backpack frame permitting full hip mobility

Backpacks have become more sophisticated in recent decades with more sophisticated frames giving a closer match to the back shape of the wearer (see my patent GB patent 9511925.1), improved shoulder harnesses which allow the body to move freely (see my NZ patent 506106) and hipbelts which shape to the body more accurately (see my NZ patent application 520476).

My patent GB 9511925.1 shows a means of spreading the load around the hips, by having connections on the hipbelt which attach to the pack positioned at 3 points equidistant around the pelvis: at the center back, and 2 points at the front of the iliac crest. The corresponding connections to the pack are located at 3 points which correspond to the tripod frame base. This allows weight to be evenly distributed between the front and the rear of the hipbelt. However, while the flexible web connections between the hipbelt and the pack allow some hip mobility, it is nowhere near the mobility of the hips which is possible without a pack on.

Hip mobility is important to allow easy body movement over uneven terrain, to prevent chafing of the hipbelt against the body and to prevent the buildup of fatigue when muscles are held fixed in one position over long periods.

An alternative frame was developed by myself where by a vertical frame member in the center of the backpanel was provided, and the base of this frame member provided the connection to the center of the hipbelt. A further member, in the shape of an inverted U was located at its center approximately level with the wearer’s lumbar dorsal pivot, and was free to pivot about this point. The ends of this curved member were located in pockets at the bottom comers of the backpanel. From these points web connections to the front portions of the hipbelt were located. Later McLachlan took out a patent NZ 335 931 on a similar system.

The disadvantage of this system was that the end portions of the inverted U frame member were constrained in their movement because they were located in a pocket or sleeve at the comer of the backpanel. This subsequently constrained the movement of the front point of the hipbelt connected thereto.

The object of the current invention is to have a frame system which spreads the load evenly around the hipbelt and hips equally both front and rear of the wearer, while at the same time allowing full hip mobility.

Accordingly, the backpack is provided with a frame comprising of one or more vertical members running between the top and bottom of the sac, said frame member or members being located in the central portion of the backpanel at their lower end. A flexible connection to the central portion of the hipbelt arises from the lower end of the frame or frames, or from the sac adjacent to the frame end.

Secondly, a frame member in the shape of an inverted U or inverted channel,which will be subsequently referred to as the U frame, is secured to the rear surface of the sac or the frame member or members approximately level with the wearer’s lumbar dorsal pivot and extends outwards and downwards symmetrically either side of the vertical frame members and further beyond the edges of the backpanel. The ends of the U frame attach to the backpanel adjacent to its lower comers via flexible connections, which allows pivoting of this U frame about the lumbar dorsal pivot in a generally vertical plane in relation to the backpanel and the vertical frame members. A flexible connection from the ends of the inverted U tube to the front portions of the hipbelt which correspond to the front portion of the iliac crests of the wearer is provided to transfer weight to the front portion or end section of the hipbelt.

In another embodiment of the invention the U frame is free to slide but is constrained from pivoting about the lumbar dorsal pivot by 2 flexible connections arranged in a V configuration, whose upper ends attach to the U frame adjacent to but either side of the lumbar dorsal pivot and whose lower ends attach near or at the center of the bottom of the backpanel or to the bottom of the frame member(s). The U frame can pivot about said lower attachment points of said connectors.

In a further embodiment of the invention, the ends of the U frame are connected to each other by a flexible member; the central portion of this flexible member is slidingly coupled to the bottom of the pack, or the lower portion of the backpanel of the pack via a sleeve or tube. The flexible member extends beyond the ends of this sleeve or tube so there is a portion of the flexible member exposed between the sleeve or tube and the ends of the U frame. The ends of the U frame are now free to move in a horizontal plane. The combination of movement of the U frame ends in both horizontal and vertical planes allows the corresponding connection to the front end portion of the hipbelt of the wearer, complete mobility in all directions. At the same time, load is transferred to the front end portion of the hipbelt and the central rear portion equally, resulting in maximum comfort.

This invention will now be further described with reference to the following illustrations:

Figure 1 shows a frame system for a backpack

Figure 2 shows a hipbelt for a backpack

Figure 3 shows an alternative frame system for a backpack

Figure 4 shows a further alternative frame system of a backpack

Figure 5 shows a portion of the frame system of a backpack

Figure 6 shows an. alternative embodiment of the portion of the frame system of a backpack

Figure 7 shows an alternative embodiment of the portion of the frame system of a backpack

Figure 8 shows an alternative embodiment of the portion of the frame system of a backpack

Figure 1 shows the frame system of a backpack located in the backpanel 1. A vertical frame member 2, shaped to the contours of the wearer’s back, is located centrally in the backpanel. Any number of horizontal stays 3 may also be incorporated to create a concave shape across the backpanel. An additional inverted U shaped frame member 4 is located to the backpanel in its central portion by sleeve 5, but is free to slide within this sleeve. The lower ends of frame 4 connect to the backpanel adjacent to its lower comers via flexible connections 6. Flexible connectors 6a join upper portions of frame 4 with central lower portion of backpanel. Frame 4 can pivot about said central lower portion of backpanel as upper portion of frame 4 slides through sleeve 5.Also located on the ends of frame 4 are flexible connectors 7 which connect towards the end portions of the hipbelt. Another flexible connection 8 is provided, arising adjacent to the center bottom of the backpanel which connects to the central portion of the hipbelt.

Figure 2 illustrates a hipbelt 9 opened flat. Centrally located is a connector 10, which may be in the form of a buckle or touch and close fastener, which connects to flexible connector 8 on the backpanel. Located towards each end of the hipbelt, at the region approximately corresponding to the iliac crests of the wearer are flexible connectors 11 which connect to flexible connectors 7 at the ends of frame member 4.

Figure 3 shows another embodiment of the invention. Two vertical frame members 12 are positioned towards the outer edges of the top of backpanel 1, and towards the center of the bottom of the backpanel. The lower ends of frame member 4 are joined by a flexible connector 13 running through a slot 14, located either in the bottom of the backpanel as illustrated or the bottom panel of the backpack. Connector 13 is free to slide freely within slot 14. Flexible connectors 7 and 8 connect to the hipbelt as before. Frame 4 is free to pivot in sleeve 5 in a generally vertical plane around sleeve 5 allowing corresponding movement of hipbelt ends via webs 7. In this embodiment frame 4 is preferably made of a straight but resiliently flexible material which curves to the shape illustrated by virtue of the ends being joined by connectors 6 and backpanel 1.

In this embodiment the ends of said frame 4 can also pivot in a generally horizontal plane by virtue of frame 4 twisting and a corresponding movement of connector 13 sliding through sleeve 14. Thus the ends of frame 4 and the corresponding ends of the hipbelt connected thereto are able to move in both horizontal and vertical planes allowing full hip mobility.

Figure 4 shows a further embodiment of the invention. Frame member 4 is shaped with a straight section 15 at the top protruding either side of sleeve 5 and is preferably made of a rigid precurved material.

Figure 5 shows an expanded view of frame member 4 illustrated in figure 4. Section 15 has inner sleeves 16 which insert in the upper ends of segments 17 so that they are free to rotate around segment 15. Alternatively, sleeves 16 can be located in the upper ends of segments 17 which insert in sleeveless ends of segment 15. Pivoting of end segments around segment 15 allows lower ends of segments 17 to move in the horizontal plane in opposite directions, with the corresponding movement of flexible member 13 sliding in sleeve 14. This allows connectors 7 attaching to corresponding connectors on the hipbelt to move freely, while at the same time weight is transferred from the ends of frame 4 to the hipbelt towards the front of the wearer and at the back of the wearer via connectors 8 attaching to corresponding connector at the center of the hipbelt.

Figure 6 shows a further embodiment of frame member 4. Segments 18 have sleeves 19 which fit into the lower ends of segments 17. Rotation of segments 18 in relation to segments 17 allows the lower ends of segments 18 to lie flat against the sides of the hipbelt, so that they don’t interfere with arm movement.

Figure 7 shows an alternative embodiment of frame member 4. It is composed of two identical segments 17 curved or angled in shape which connect via sleeve 16 so that segments 17 can rotate relative to each other.

Figure 8 shows an elaboration of the frame member 4 shown in Figure 7. Segments 18 have sleeves 19 which fit into the lower ends of segments 17. Rotation of segments 18 in relation to segments 17 allows the lower ends of segments 18 to lie flat against the sides of the hipbelt.

In figures 4-8 segments 15,17,1.8 may be of a hollow section and an internal cord may be used to hold these segments together.