US20090165205A1

US20090165205A1 - Hammock Having Insulation Retaining Panels

Info

Publication number: US20090165205A1
Application number: US12/399,277
Authority: US
Inventors: Thomas Hennessy
Original assignee: Hennessy Holdings Ltd
Current assignee: Hennessy Holdings Ltd
Priority date: 2007-05-15
Filing date: 2009-03-06
Publication date: 2009-07-02

Abstract

A thermally insulated hammock is provided with a pair of insulation retaining panels, one secured to either side of the hammock bed. The panels can be drawn across the bottom surface of the hammock and fastened so as to hold one or more insulation pads against the bottom surface of the hammock bed in cold weather. The retaining panels may be rolled up out of the way and tied at the edges of the hammock when insulation is not needed.

Description

This application is a continuation-in-part of patent application Ser. No. 11/748,910, filed May 15, 2007.

FIELD OF THE INVENTION

This invention relates to hammocks, particularly to a hammock having thermal insulation attached to the underside of the hammock bed for cold weather.

BACKGROUND OF THE INVENTION

For camping and other recreational activities, various hammocks have been developed to provide shelter from insects, ground dwelling creatures and inclement weather. Being suspended above the ground, hammocks are more comfortable, drier, warmer and cleaner than are tents.
Traditional hammocks were entered by climbing over one side. That was difficult and sometimes dangerous, because the hammock was out of balance when a person entered it. The potential occupant pushed down one of the higher sides of the hammock, as low as possible, toward its longitudinal axis of symmetry, to gain access. As soon as the person sat down and his weight came off of his feet, the hammock swung back into its original position, possibly tumbling the person backward, out of the hammock.
In my U.S. Pat. No. 6,185,763, I described a hammock which had a partial entrance slit running from one end of the hammock about half the hammock length, so that one could enter the hammock simply by standing up through the slit from a position directly beneath one end of the hammock, and then reclining on the unslit portion of the bed. The person's weight induced lengthwise tension in the fabric, which closed the slit so well that he or she could lie right on the slit and not fall out.
I had originally thought that the slit must extend along the longitudinal center plane of the hammock, where the tension forces are the greatest; however, I found that not to be so and my U.S. Pat. No. 6,865,757—which is also incorporated herein by reference—discloses a different hammock which is asymmetrical. That design encourages one to lie not along the tension axis established by the ropes at either end, as one does in most hammocks, but rather diagonally across the tension axis. Doing so improves comfort because the spine is supported in a way that does not force it to conform to the downward curvature of the hammock.
My above patents describe strong, lightweight hammocks suitable for warm weather use; however, I also desire to enable hammock users to sleep in the cold. A sleeping bag alone is not sufficient to keep the occupant warm through the night as the bottom insulation of a sleeping bag is compressed by the user's weight, which reduces the insulation factor significantly.
It is common practice to insert a closed cell foam pad or inflatable air mattress into a hammock, beneath a sleeping bag, to reduce heat loss through the bottom of the hammock. By adding blankets or a quilt, one can be well insulated from above; however, the bottom of the sleeping bag, and any additional insulation, is compressed by the user's weight, which reduces the insulation factor. A great deal of body heat may be lost through the hammock bottom on cold nights, particularly when there is a wind, and it would be better to have a hammock whose bed was insulated to reduce the heat loss.
Insulated hammocks are well known; however, the conventional design—see U.S. Pat. No. 3,675,256 for an example—is to insulate the full width of the hammock bed with a single piece of insulation. Managing insulation pads inside the hammock is awkward; the pads can move under the occupant as he turns and tosses during the night. The pad can even pop out from underneath the occupant, leaving him or her with a cold back. Another disadvantage of this arrangement of insulating material is that it can interfere with entry into or exit from the hammock through the bottom, particularly if the hammock is of the bottom-entry type.

SUMMARY OF THE INVENTION

An object of this invention is to improve the warmth and comfort of a hammock having a bottom entrance slit, without interfering with a person's ability to enter or exit the hammock.
A further object is to allow a person to place a selected amount of thermal insulation against the underside of a hammock bed to control the amount of heat loss from the hammock's occupant through the bottom of the hammock.
Another object is to enable one—when insulation is not needed—to remove the insulation pad and stow the insulation retaining panels at either side of the hammock, out of contact with the user.
These and other objects of the invention will be apparent from the drawings and the following description, augmented by the description contained in U.S. Pat. No. 6,185,763, which is incorporated by reference herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a hammock having an entrance slit which bisects the hammock fabric and extends along the tension axis as shown in my U.S. Pat. No. 6,185,763;

FIG. 2 is a laid-out view of the fabric portion of the symmetrical FIG. 1 hammock, showing the centered location of the entrance slit;

FIG. 3 is a top plan view thereof, showing the ends gathered and attached to suspending ropes, with a person lying diagonally across the entrance slit;

FIG. 4 is a laid-out view of the fabric portion of an asymmetrical hammock, showing a laterally offset entrance slit; and

FIG. 5 is a top plan view of thereof, again showing the ends gathered and attached to suspending ropes, with a person lying diagonally on the symmetrical hammock but not across the entrance slit.

FIG. 6 is a bottom plan view of the hammock embodying the present invention, showing a pair of overlapping insulation retaining panels;

FIG. 7 is a sectional view of the hammock, taken on the plane 7-7 in FIG. 6; and

FIG. 8 is a view like FIG. 7, showing the insulation retaining panels stowed at the sides of the hammock.

FIG. 9 is a view like FIG. 7, showing an alternative form of the retaining panels;

FIG. 10 is view like FIG. 7, showing another alternative form of the retaining panels; and

FIG. 11 is an enlarged sectional view of the hammock insulation layers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A hammock 10 embodying the invention comprises a bed 12 and an insect net 14. The net is located above the bed and is attached along the net's edges 16 to the longitudinal edges 18 of the bed. Each end 20 of the bed is gathered and connected by a suspending rope 22 to one of a pair of spaced anchors 24 such as trees.
An optional canopy 26 overhangs the insect net 14. Cords 58, 62 extending from the midpoint 56 of the bed and canopy, respectively, may be tied to anchors 60, 64 at either side of the hammock to keep the bed and the canopy spread out.
The bed 12 of the hammock is made from a substantially rectangular sheet 28 (see FIG. 2) of flexible breathable material. It must be of sufficient strength and resilience to withstand an appropriate load and repeated use under varying conditions. Nylon, polyester or a synthetic fabric with similar qualities is used.
In one version, not essential to the present invention, an entrance slit 30 extends from one of the short edges 32 of a substantially rectangular sheet 28 for about half the length of the bed. The short edges 32 of the rectangular sheet 28 are folded several times parallel to the longitudinal axis “T” of sheet 28. This gathering of the bed material is described in detail in U.S. Pat. No. 6,185,763.
To enter the hammock, a person crouches or stoops so that he is directly below the hammock slit, and then stands up through the slit, either entering head first and turning around inside the hammock, or backing in until the back of his knees contact the low end of entrance slit 30. Then, the person sits down on the unslit portion of the bed 12, which tensions the sheet 28, particularly the lengthwise (warp) threads.
As the person reclines against the bed 12, lifting the legs off the ground, his entire weight is supported by tension in the fabric. Then, as the occupant lifts his legs through the entrance slit 30, the slit snaps closed under tension, providing secure support and a bug-proof environment.
Although the material of the hammock's bed is described above as a woven fabric, it should be understood that the inventive aspects do not depend on the nature of the material and thus the claims below refer to a “sheet” of material. The material could indeed be a non-woven fibrous material, a film, foil or another thin, strong and preferably breathable material perhaps yet to be invented.
The improvement which I now claim as my invention is shown in FIGS. 6-11.
One version of the invention (FIGS. 6-8) has a pair of insulation retaining panels 70, 72 which can be drawn across the bottom surface of the bed, in an overlapping arrangement beneath a pad 74 of insulation. The insulation may include one or more of the following: felt, woven material, feathers, down, loose bulky material, spun insulation, and polymeric foam (open celled or closed celled).
Each retaining panel is fixed or attachable along one edge 76 to one respective lateral edge 78 of the bed. The apex 80 of the retaining panel, opposite the fixed edge, is provided with a fastener for joining the two retaining panels or holding them in an overlapping relationship.
For the version where the retaining panels overlap, the fastener could be an elastic cord 82 with a hook or loop at one end which can be connected to structure such as a ring 84 or other anchor on the opposite lateral edge 86 of the bed, as shown in FIGS. 6 and 7.
In any case, when the insulation is not needed, the fasteners can be released and the insulation pad(s) removed. The retaining panels may then be rolled up toward the fixed edge, as shown in FIG. 8, and secured at the edge of the bed by suitable ties or other fasteners. It should be apparent that, rather than removing the insulation, one can roll up the insulation together with the retaining panels.
In another version of the bed (FIG. 9), the insulation retaining panels 70′, 72′ do not overlap but, rather, meet at opposed edges, to which complementary fasteners 73, 75 such as zippers, buttons or hook-and-loop fasteners (“Velcro”) have been applied to join the edges together.
In a further version of the bed (FIG. 10), the insulation retaining panels 70″,72″ each comprise two layers of fabric that form a pocket 77 into which one or more pieces of insulation 74 can be placed. The size and number of insulation layers can be selected to achieve the desired degree of warmth.
FIG. 11 shows an enlarged sectional view of a portion of the bed 12, an insulation layer 74 below it, and a retaining panel 70 bottommost. The insulation layer(s) may be any type of material suitable for use as bedding, including felt, woven material, feathers, loose bulky material or spun insulation. Open cell foam, especially foam having a waffled surface, is particularly desirable because it is light and can be highly compressed for transport.
Whichever version is selected, the weight of the person is supported by the hammock fabric above the insulation, not by the insulation itself. This avoids compressing the insulation, which would reduce its thermal value.
A metallicized heat-reflecting layer (“emergency space blanket”) 88 may be added as a separate element or may be laminated to the insulation layer to reduce radiant heat loss. The metallic layer should be between the hammock and the insulation for best effect.
If any chosen insulating material is not itself resistant to tearing, it may be encased in an envelope made of a strong material, or laminated with such material, or it may be manufactured with an integral skin to provide strength and reduce or eliminate permeability to air, water and other fluids.
While I have described the insulation as being a removable pad or pads of material, the insulation could be secured within a pocket formed in—or permanently attached to—one or both of the retaining panels.
Inasmuch as the invention is subject to many variations and modifications, it is intended that the description and drawings shall be interpreted as merely examples of the invention defined by the claims below.

Claims

1. A hammock comprising

a bed made of a piece of sheet material gathered at opposite ends and joined at each said end to a suspension rope, said bed having lateral edges extending between said opposite ends,

a pair of flexible retaining panels for holding thermal insulation against the bottom of the bed, each retaining panel being secured along at least one edge thereof to the bed, the retaining panels being sized so that they meet or overlap when the panels are drawn together beneath the hammock bed, and

at least one releasable fastener for securing the panels in their drawn together configuration.

2. The invention of claim 1, wherein said fastener is a zipper or hook-and-loop fastener with complementary portions attached to the respective free edges of the retaining panels.

3. The invention of claim 1, wherein said fastener comprises an elastic cord.

4. The invention of claim 1, wherein said panels are sized so that they overlap substantially in their drawn together configuration.

5. The invention of claim 1, wherein said bed has an entrance slit running from one of said ends to a point intermediate said ends.

6. The invention of claim 1, further comprising at least one layer of thermal insulation placed between the hammock bed and the insulation retaining panel.

7. The invention of claim 6, further comprising a metallicized heat reflecting layer placed above the insulation layer.

8. The invention of claim 6, wherein said thermal insulation is an open-celled foam.

9. The invention of claim 6, wherein said thermal insulation has an integral skin.

10. The invention of claim 6, wherein the retaining panel forms a pocket into which at least one piece of thermal insulation may be placed.

11. The invention of claim 6, wherein the thermal insulation layer is attached to the retaining panel.

12. The invention of claim 6, wherein the insulation is selected from the group consisting of felt, woven material, feathers, down, loose bulky material, spun insulation, and polymeric foam.

13. The invention of claim 1, wherein at least one of the retaining panels is permanently secured to the hammock bed.

14. The invention of claim 1, wherein at least one of the retaining panels is detachably secured to the hammock bed.