Backpack ventilator

Abstract

A backpack ventilator is described. An embodiment of the present invention includes a portion of mesh fabric that is attached to a conventional fabric and a spring wire perimeter frame is inserted between them. Stretched between various points on the frame is a plurality of springs. The resulting backpack ventilator is secured between a backpack and the wearer. The springs distribute the pressure from the backpack across a wide contact area to increase comfort for the wearer. The backpack ventilator significantly increases airflow ventilation between the wearer and the backpack. As the wearer moves, the frame and springs absorb some of the impact forces that would otherwise be directed towards the wearer. Furthermore, the movement also causes the ventilator to draw air in and out of the mesh fabric thereby reducing heat and sweat buildup.

Description

TECHNICAL FIELD

The invention relates generally to hiking and backpacking equipment, and more particularly to a backpack or backpack add-on device that facilitates ventilation between a wearer and a backpack.

BACKGROUND

Backpacks and other means for helping humans carry loads have been around for thousands of years. In relatively recent times, daypacks, fanny-packs, rucksacks, school book-bags, hunting-packs, and a plethora of like-devices (collectively, backpacks) have appeared on the market. The size, shape, color, carrying-capacity, etc. differ widely among backpacks, but they all have one thing in common: they are designed to be carried in such a way that they are positioned against the wearer's body. For example, common daypacks are designed to be worn against the back with shoulder straps securing the backpack in place. Some daypacks also utilize a waist-belt as well. In either case, the closeness of the backpack to the wearer's body causes heat and sweat to build-up between the backpack and the wearer's body.

Obviously, such excess heat and sweat are uncomfortable for the wearer and can lead to more serious problems such as heat-exhaustion. If the backpack is not waterproof, excess sweat can soak through the pack and adversely affect the contents of the backpack. These problems are especially onerous when a backpack must be worn for extended periods and when walking significant distances.

In order to address some of these issues, a number of existing products have been developed. For example, a number of backpacks utilize specialized pads that are placed between the backpack and the wearer (e.g., U.S. Pat. No. 5,911,348). Such devices are designed to create pockets of increased airflow between the pads. However, the contact between the pads and the wearer's body still causes heat and sweat buildup—the contact area is focused into a smaller total area, but the pressure exerted by the pack on that area is consequently that much greater.

Another common approach to addressing the excess heat and sweat buildup problems is to utilize internal rods or stiffening supports in a backpack to hold the pack up and off the wearer's body (e.g., U.S. Pat. No. 5,823,414). However, as with the use of specialized pads discussed above, the rods or supports only serve to decrease the contact surface area and increase the pressure on that area. Furthermore, as the load-weight in the backpack is increased, the focused pressure caused by the pads or rods can become extremely uncomfortable for the wearer.

There is therefore a need for a backpack or backpack add-on that can sufficiently ventilate the contact area in order to reduce the wearer's heat and sweat buildup.

SUMMARY

Embodiments of the present invention described and claimed herein address the foregoing problems by application of a device that ensures adequate ventilation between a backpack and the wearer. Various embodiments are described and recited herein. Although materials and methods similar or equivalent to those described herein can be used in the practice of the invention, suitable materials and methods are described below. Furthermore, the materials, methods, and examples are illustrative and not intended to be limiting.

In one embodiment, a portion of stiff mesh fabric is attached to a like portion of conventional fabric and a spring wire perimeter frame is inserted between them. Stretched between various points on the frame is a plurality of springs. The resulting backpack ventilator is secured between a backpack and the wearer. The springs distribute the pressure from the backpack across a wide contact area to reduce pressure points and increase comfort for the wearer. The mesh fabric and the springs work together to significantly increase airflow ventilation between the wearer and the backpack. Furthermore, the frame can be shaped to more closely match the individual contours of the wearer.

In another embodiment, the backpack ventilator is built into a backpack and is therefore non-removable.

As the wearer walks, hikes, or otherwise moves, the motion of the wearer and the backpack causes the backpack ventilator to flex and move as well. The frame and springs absorb some of the impact forces that would otherwise be directed towards the wearer. Furthermore, the movement also causes the ventilator to draw air in and out of the mesh fabric thereby reducing heat and sweat buildup.

The present invention provides many benefits over the prior art. Compared to a normal backpack having no special ventilation enhancements, the backpack ventilator significantly increases airflow and breathability between the backpack and the wearer. Excess sweat and heat buildup are virtually eliminated. Compared to other enhanced-airflow backpacks, the ventilator has a much larger contact surface area with the wearer, reducing the focused pressure and resultant heat and sweat buildup on the pads or rods used in other enhanced-airflow backpacks. Furthermore, because of the flexing and stress-absorbing nature of the frames and springs, the ventilator is able to flex and move with the wearer to reduce pressure-points and backpack-carrying fatigue.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned and other features and objects of the present invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following descriptions of a preferred embodiment and other embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates a perspective view of an exemplary embodiment of a backpack ventilator in position between a wearer and a backpack.

FIG. 2 illustrates a front view of an exemplary embodiment of a backpack ventilator.

FIG. 3 illustrates a side view of an exemplary embodiment of a backpack ventilator.

FIG. 4 illustrates an exploded front view of an exemplary embodiment of a backpack ventilator.

FIG. 5 illustrates a perspective view of the internal frame and springs of an exemplary embodiment of a backpack ventilator.

FIG. 6 illustrates a cross sectional side view of an exemplary embodiment of a backpack ventilator.

FIG. 7 illustrates a cross sectional side view of an exemplary embodiment of a backpack ventilator integrated into a backpack.

FIG. 8 illustrates a perspective view of an exemplary embodiment of a backpack ventilator.

FIG. 9 illustrates a close-up perspective view of an exemplary embodiment of a backpack ventilator with top attachment tabs.

FIG. 10 illustrates a close-up perspective view of an exemplary embodiment of a backpack ventilator with bottom attachment tabs.

DETAILED DESCRIPTION

A backpack ventilator is described. In one embodiment, the backpack ventilator comprises a stand-alone, add-on device that can be attached to a similarly sized and shaped backpack. In another embodiment, the backpack ventilator is integrated into a backpack and together they comprise the entire backpack ventilator system.

In one embodiment, a portion of stiff mesh fabric is attached to a like portion of conventional fabric and a spring wire perimeter frame is inserted between them. Other types of breathable and conventional fabrics are contemplated. Also, the perimeter frame can be constructed using different materials than the spring wire.

Stretched between various points on the frame is a plurality of springs. The springs can be standard metallic coil springs or any other suitable material that provides breathability, cushioning, support, etc. The springs are not necessarily attached to or stretched between points on the frame. Instead, any means of securing the spring materials to the backpack ventilator may be used. Suitable spring materials could include, but are not limited to: plastics, metals, woods, fibers, etc. Suitable spring shapes include, but are not limited to: balls, coil springs, corrugations, honeycombs, etc.

The resulting backpack ventilator is secured between a backpack and the wearer. The springs distribute the pressure from the backpack across a wide contact area to reduce pressure points and increase comfort for the wearer. The mesh fabric and the springs work together to significantly increase airflow ventilation between the wearer and the backpack. Furthermore, the frame can be shaped to more closely match the individual contours of the wearer.

FIG. 1 illustrates a perspective view of an exemplary embodiment of a backpack ventilator 100 in position between a wearer and a backpack. Because the backpack ventilator 100 is in position between a wearer 105 and a backpack 170, details concerning the components of the ventilator 100 can not be seen. Such details are shown and described in reference to FIG. 2, below.

The backpack 170 shown in FIG. 1 is an exemplary daypack-type pack. The ventilator 100 may, of course, be used with many other types and styles of backpacks. Furthermore, the placement of the ventilator 100 can vary from that shown in FIG. 1.

FIG. 2 illustrates a front view of an exemplary embodiment of a backpack ventilator 200. The primary components of the embodiment shown in FIG. 2 include: a first fabric 210; a first top attachment tab 220 shown in the open, unattached position; a second top attachment tab 230 shown in the open, unattached position; a first bottom attachment tab 240 shown in the open, unattached position; a second bottom attachment tab 250 shown in the open, unattached position; and an internal frame 260.

In the embodiment illustrated in FIG. 2, the first fabric 210 is shown. The first fabric 210 is a breathable fabric that is placed towards the wearer 105 when the ventilator 200 is properly positioned between the wearer 105 and the backpack 170. The first fabric 210 is shown as a stiff, mesh fabric. In other embodiments, other types of breathable coverings are contemplated. The first fabric 210 is designed to contain the interior structure of the ventilator 200 while being flexible and breathable so as to maximize the comfort of the wearer 105.

The first fabric 210 is basically flat, having an outer side facing the wearer 105, an inner side facing the interior structure of the ventilator 200, and a thin edge around its perimeter. The first fabric 210 plays a significant part in the functionality by allowing the ventilator 200 to freely circulate air around the contact area between the ventilator 200 and the wearer 105. The first fabric 210 and the second fabric 315 (see FIG. 3) are attached to one another around their perimeters forming an envelope containing the interior structure of the ventilator 200. The second fabric 315 is not shown in FIG. 2. As the second fabric 315 is positioned against the backpack 170, it does not need to be breathable and so can be constructed using conventional fabric or some other suitable material. In an alternate embodiment, the second fabric 315 is also made to be breathable.

A first top attachment tab 220 is illustrated in FIG. 2 in an open, unattached position. The first top attachment tab 220 is used to secure the ventilator 200 to the backpack 170. In a standard configuration for one embodiment, the top portion of a first backpack shoulder strap is placed within the first top attachment tab 220 and the tab 220 is closed. A second top attachment tab 230 is illustrated in FIG. 2 in an open, unattached position. The second top attachment tab 230 is used to secure the ventilator 200 to the backpack 170. In a standard configuration for one embodiment, the top portion of a second backpack shoulder strap is placed within the second top attachment tab 230 and the tab 230 is closed.

A first bottom attachment tab 240 is illustrated in FIG. 2 in an open, unattached position. The first bottom attachment tab 240 is used to secure the ventilator 200 to the backpack 170. In a standard configuration for one embodiment, the bottom portion of a first backpack shoulder strap is placed within the first bottom attachment tab 240 and the tab 240 is closed. A second bottom attachment tab 250 is illustrated in FIG. 2 in an open, unattached position. The second bottom attachment tab 250 is used to secure the ventilator 200 to the backpack 170. In a standard configuration for one embodiment, the bottom portion of a second backpack shoulder strap is placed within the second bottom attachment tab 250 and the tab 250 is closed.

In one embodiment, the attachment tabs 220, 230, 240, and 250 are made of light nylon webbing. In another embodiment, shoe-lace type materials are utilized. In yet another embodiment, hook-and-loop materials can be used. Other means of attaching the ventilator 200 to the backpack 170 are contemplated and can be utilized without departing from the scope of the invention.

It will readily be understood that the various attachment components of this embodiment could be implemented by the use of other equivalent snaps, ties, etc. and that various modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

The perimeter frame 260 illustrated in FIG. 2 is constructed using a spring wire shaped to match the perimeter of the chosen backpack 170. The use of other suitable materials to construct the perimeter frame 260 is contemplated. The frame 260 functions to hold and define the outer shape of the ventilator 200. In one embodiment, the frame 260 is shaped to match the backpack 170. In another embodiment, the frame 260 is ergonomically shaped to conform to the wearer's 105 contours. In yet another embodiment, the frame 260 is shaped to conform to both the contours of the backpack 170 and of the wearer 105. The frame 260 can also be used to hold the springs (not shown in FIG. 2; see FIG. 4, springs 465) in place.

FIG. 3 illustrates a side view of an exemplary embodiment of a backpack ventilator 300. The primary components of the embodiment shown in FIG. 3 include: a first fabric 310; a second fabric 315; a first top attachment tab 320 shown in the open, unattached position; and a first bottom attachment tab 340 shown in the open, unattached position.

In the embodiment illustrated in FIG. 3, the first fabric 310 is shown.

The first fabric 310 is a breathable fabric that is placed towards the wearer 105 when the ventilator 300 is properly positioned between the wearer 105 and the backpack 170. The first fabric 310 is shown as a stiff, mesh fabric. In other embodiments, other types of breathable coverings are contemplated. The first fabric 310 is designed to contain the interior structure of the ventilator 300 while being flexible and breathable so as to maximize the comfort of the wearer 105.

The first fabric 310 is basically flat, having an outer side facing the wearer 105, an inner side facing the interior structure of the ventilator 300, and a thin edge around its perimeter. The first fabric 310 plays a significant part in the functionality by allowing the ventilator 300 to freely circulate air around the contact area between the ventilator 300 and the wearer 105. The first fabric 310 and the second fabric 315 are attached to one another around their perimeters forming an envelope containing the interior structure of the ventilator 300. As the second fabric 315 is positioned against the backpack 170, it does not need to be breathable and so can be constructed using conventional fabric or some other suitable material. In an alternate embodiment, the second fabric 315 is also made to be breathable.

A first top attachment tab 320 is illustrated in FIG. 3 in an open, unattached position. The first top attachment tab 320 is used to secure the ventilator 300 to the backpack 170. In a standard configuration for one embodiment, the top portion of a first backpack shoulder strap is placed within the first top attachment tab 320 and the tab 320 is closed. A first bottom attachment tab 340 is illustrated in FIG. 3 in an open, unattached position. The first bottom attachment tab 340 is used to secure the ventilator 300 to the backpack 170. In a standard configuration for one embodiment, the bottom portion of a first backpack shoulder strap is placed within the first bottom attachment tab 340 and the tab 340 is closed.

A series of small loops 341, 342, 343, 344 and 345 are shown in FIG. 3 which allow the first bottom attachment tab 340 to be threaded through at different heights and spacings, in order to accommodate different first shoulder strap 772 attachments on various backpacks 170. Although not depicted in FIG. 3, a second series of small loops allows the second bottom attachment tab 250 to be threaded through at different heights and spacings, in order to accommodate different second shoulder strap 874 attachments on various backpacks 170.

It will readily be understood that the various attachment components and series of loops of this embodiment could be implemented by the use of other equivalent snaps, ties, etc. and that various modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

FIG. 4 illustrates an exploded front view of an exemplary embodiment of a backpack ventilator 400. FIG. 4 is meant to highlight the position of the interior structures of the ventilator 400. Therefore, FIG. 4 is very similar to FIG. 2 and the two figures can be compared in order to illustrate the placement of the interior structures. The primary components of the embodiment shown in FIG. 4 include those listed in FIG. 2 plus the interior components: a first fabric 410; a first top attachment tab 420 shown in the open, unattached position; a second top attachment tab 430 shown in the open, unattached position; a first bottom attachment tab 440 shown in the open, unattached position; a second bottom attachment tab 450 shown in the open, unattached position; a perimeter frame 460; and a plurality of springs 465.

For a description of the first fabric 410 and the attachment tabs 420, 430, 440, and 450 see the descriptions under FIG. 2 above. The perimeter frame 460 illustrated in FIG. 4 is constructed using a spring wire shaped to match the perimeter of the chosen backpack 170. The use of other suitable materials to construct the perimeter frame 460 is contemplated. The frame 460 functions to hold and define the outer shape of the ventilator 400. In one embodiment, the frame 460 is shaped to match the backpack 170. In another embodiment, the frame 460 is ergonomically shaped to conform to the wearer's 105 contours. In yet another embodiment, the frame 460 is shaped to conform to both the contours of the backpack 170 and of the wearer 105.

The plurality of springs 465 are stretched between various points on the frame 460. The springs 465 can be standard metallic coil springs or any other suitable material that provides breathability, cushioning, and support. The springs 460 distribute the pressure from the backpack 170 across a wide contact area to reduce pressure points and increase comfort for the wearer 105. The first fabric 410 and the springs 465 work together to significantly increase airflow ventilation between the wearer 105 and the backpack 170.

It will readily be understood that the various springs 465 components of this embodiment could be implemented by the use of other equivalent materials (e.g., plastic springs, pocketed coil springs, a plurality of small balls, a series of corrugations, a structure of honeycombs, etc.) and that various modifications may be made without departing from the spirit of the invention and the scope of the appended claims. In one embodiment, the springs 465 and the frame 460 are separate components. In another embodiment, the functionality of the frame 460 is integrated into the springs 465.

FIG. 5 illustrates a perspective view of the internal frame and springs 500 of an exemplary embodiment of a backpack ventilator. The primary components of the embodiment shown in FIG. 5 include a perimeter frame 560; and a plurality of springs 565. For a description of the perimeter frame 560 and the plurality of springs 565, see the description given above in reference to FIG. 4.

FIG. 6 illustrates a cross sectional side view of an exemplary embodiment of a backpack ventilator 600. The primary components of the embodiment shown in FIG. 6 include: a first fabric 610; a second fabric 615; a first top attachment tab 620 shown in the open, unattached position; and a plurality of springs 665. Also shown in dashed lines is a backpack 670 with a first shoulder strap 672.

Because the embodiment illustrated in FIG. 6 is shown in cross-section, it is easy to see that the plurality of springs 665 is placed between the first fabric 610 and the second fabric 615. For a description of the first top attachment tab 620 see the description for the first top attachment tab 220 in FIG. 2. The first fabric 610 and the second fabric 615 are attached to one another around their perimeters forming an envelope containing the plurality of springs 665 of the ventilator 600.

FIG. 7 illustrates a cross sectional side view of an exemplary embodiment of a backpack ventilator integrated into a backpack 700. As can be seen in this embodiment, the frame 760, the springs 765, and the first fabric 710 are integrated into the backpack 770 forming the complete backpack ventilator 700. The first fabric 710 encloses the springs 765 and the frame 760 against the panel of the backpack 770 that is designed to be worn against the wearer's back. Because the panel of the backpack 770 is attached to the first fabric 710 and the two thereby enclose the frame 760 and the springs 765, there is no need for a second fabric. Also shown in FIG. 7 is a first shoulder strap 772.

Although not shown in FIG. 7, the panel of the backpack 770 that is designed to be worn against a portion of the wearer is often padded and/or shaped to be more comfortable for the wearer. Any such padding or shaping can be applied to the first fabric 710, springs 765 and frame 760 in order to preserve the benefits thereof for the wearer.

It will readily be understood that the shape, size, style, contours, and type of backpack 770 shown in this embodiment could be implemented by the use of other equivalent backpacks (e.g., fanny-packs, day-packs, rucksacks, etc.) and that various modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

FIG. 8 illustrates a perspective view of an exemplary embodiment of a backpack ventilator 800. The primary components of the embodiment shown in FIG. 8 include: a first fabric 810; a first top attachment tab 820 shown in the closed, attached position; a second top attachment tab 830 shown in the closed, attached position; a first bottom attachment tab 840 shown in the closed, attached position; and a second bottom attachment tab 850 shown in the closed, attached position.

A first top attachment tab 820 is illustrated in FIG. 8 in a closed, attached position. The first top attachment tab 820 is used to secure the ventilator 800 to the backpack 870. In a standard configuration for one embodiment, the top portion of a first backpack shoulder strap 872 is placed within the first top attachment tab 820 and the tab 820 is closed. A second top attachment tab 830 is illustrated in FIG. 8 in a closed, attached position. The second top attachment tab 830 is used to secure the ventilator 800 to the backpack 870. In a standard configuration for one embodiment, the top portion of a second backpack shoulder strap 874 is placed within the second top attachment tab 830 and the tab 830 is closed.

A first bottom attachment tab 840 is illustrated in FIG. 8 in a closed, attached position. The first bottom attachment tab 840 is used to secure the ventilator 800 to the backpack 870. In a standard configuration for one embodiment, the bottom portion of a first backpack shoulder strap 872 is placed within the first bottom attachment tab 840 and the tab 840 is closed. A second bottom attachment tab 850 is illustrated in FIG. 8 in a closed, attached position. The second bottom attachment tab 850 is used to secure the ventilator 800 to the backpack 870. In a standard configuration for one embodiment, the bottom portion of a second backpack shoulder strap 874 is placed within the second bottom attachment tab 850 and the tab 850 is closed.

It will readily be understood that the various attachment components of this embodiment could be implemented by the use of other equivalent snaps, ties, etc. and that various modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

FIG. 9 illustrates a close-up perspective view of an exemplary embodiment of a backpack ventilator 900 with top attachment tabs. A first top attachment tab 920 is illustrated in FIG. 9 in a closed, attached position. In a standard configuration for one embodiment, the top portion of a first backpack shoulder strap 972 is placed within the first top attachment tab 920 and the tab 920 is closed to secure the ventilator 900 to the backpack 970. A second top attachment tab 930 is illustrated in FIG. 9 in a closed, attached position. In a standard configuration for one embodiment, the top portion of a second backpack shoulder strap 974 is placed within the second top attachment tab 930 and the tab 930 is closed to secure the ventilator 900 to the backpack 970.

FIG. 10 illustrates a close-up perspective view of an exemplary embodiment of a backpack ventilator 1000 with bottom attachment tabs. A first bottom attachment tab 1040 is illustrated in FIG. 10 in a closed, attached position. A series of small loops 1043, 1044, and 1045 are shown in FIG. 10 which allow the first bottom attachment tab 1040 to be threaded through at different heights and spacings, in order to accommodate different shoulder strap 1072 attachments on various backpacks 1070. Additional small loops not shown in FIG. 10 can further enhance the flexibility of positioning the first bottom attachment tab 1040. In a standard configuration for one embodiment, the bottom portion of a first backpack shoulder strap 1072 is placed within the first bottom attachment tab 1040 and the tab 1040 is closed to secure the ventilator 1000 to the backpack 1070.

The descriptions above illustrate exemplary components that can make up an exemplary backpack ventilator. The above specification, examples and data provide a description of the structure and use of exemplary embodiments of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims, including those hereinafter appended. Other embodiments are therefore contemplated.

Claims

1. A backpack ventilator, comprising:

a first fabric having a first shape and a second fabric having a second shape, wherein the first shape is similar to the second shape;

a frame is placed between the first fabric and the second fabric;

a plurality of springs is placed between the first fabric and the second fabric;

the first fabric is attached to the second fabric around a perimeter thereby enclosing the frame and the plurality of springs between the first fabric and the second fabric; and

wherein a plurality of attachment components are affixed to the perimeter and comprise a means of securing the perimeter to a backpack.

2. The backpack ventilator of claim 1, wherein the first fabric comprises a stiff, mesh fabric.

3. The backpack ventilator of claim 1, wherein the frame comprises a spring wire shaped to fit within the perimeter.

4. The backpack ventilator of claim 2, wherein the frame comprises a spring wire shaped to fit within the perimeter.

5. The backpack ventilator of claim 1, wherein the plurality of springs are stretched between and connected to the frame.

6. The backpack ventilator of claim 2, wherein the plurality of springs are stretched between and connected to the frame.

7. The backpack ventilator of claim 3, wherein the plurality of springs are stretched between and connected to the frame.

8. The backpack ventilator of claim 4, wherein the plurality of springs are stretched between and connected to the frame.

9. The backpack ventilator of claim 1, wherein the frame is integrated into the plurality of springs.

10. The backpack ventilator of claim 4, wherein the plurality of springs are not connected to the frame.

11. A backpack ventilator integrated into a backpack, comprising:

a fabric having a first shape;

a backpack panel having a second shape, wherein the first shape is similar to the second shape;

a backpack is attached to the backpack panel;

a frame is placed between the fabric and the backpack panel;

a plurality of springs is placed between the fabric and the backpack panel; and

wherein the first fabric is attached to the backpack panel around a perimeter thereby enclosing the frame and the plurality of springs between the first fabric and the backpack panel.

12. The backpack ventilator of claim 11, wherein the first fabric comprises a stiff, mesh fabric.

13. The backpack ventilator of claim 11, wherein the frame comprises a spring wire shaped to fit within the perimeter.

14. The backpack ventilator of claim 12, wherein the frame comprises a spring wire shaped to fit within the perimeter.

15. The backpack ventilator of claim 11, wherein the plurality of springs are stretched between and connected to the frame.

16. The backpack ventilator of claim 12, wherein the plurality of springs are stretched between and connected to the frame.

17. The backpack ventilator of claim 13, wherein the plurality of springs are stretched between and connected to the frame.

18. The backpack ventilator of claim 14, wherein the plurality of springs are stretched between and connected to the frame.

19. The backpack ventilator of claim 11, wherein the frame is integrated into the plurality of springs.

20. The backpack ventilator of claim 14, wherein the plurality of springs are not connected to the frame.