Sleeping Bag Construction

Abstract

Mummy-type insulated sleeping bag, particularly for Winter, Alpine and other severe weather, providing unusual loft and warmth with minimal weight, elimination of coldspots and suitable for use in an emergency by two persons.

Description

The present invention relates generally to sleeping bags and, more particularly, to sleeping bags of superior warmth and versatility.

Quilted sleeping bags are utilized to provide warmth and comfort to persons who of either necessity or sport sleep out of doors or in unheated quarters. In many outdoor activities it is highly desirable that the weight and bulk of the sleeping bag be as small as possible while still providing sufficient warmth and protection to the user. Sleeping bags designed for extreme weather conditions, such as are encountered in wilderness travel and mountaineering epitomize the almost inherent conflicting requirements, i.e., low weight and low bulk when packed versus the necessity for providing very efficient insulation and greath warmth and thickness when in use.

For example, still air temperatures in the mountains of the United States of 30.degree. to 50.degree. Fahrenheit below zero are not uncommon and still air temperatures in Northern Canada and Alaska are often even lower. Further, high winds may often also be present which further depress effective air temperature. At the same time, since a substantial amount of gear and equipment in addition to the sleeping bag must also be carried, often by back-pack and without assistance, keeping the weight of the sleeping bag to a minimum is highly important to such use. In addition to mere warmth, however, a sleeping bag must be porous so that moisture can escape and for maximum comfort, the bag should be adjustable by the user to provide varying degrees of warmth and/or venting of excess heat generated within the bag so as to be usable under conditions of varying severity.

As further criteria for sleeping robes or bags, it is desirable that they be washable or otherwise easily cleanable, easily aired-out and be "fail-safe" so that if a drawstring breaks, a button falls off, a zipper jams, or the like, the entire utility of the robe will not be lost since repairs of this nature can be exceedingly difficult, it not impossible, to effect under wilderness or mountaineering conditions and failure of the sleeping bag may easily prove fatal. Yet further, it is desirable that the bag be adaptable for emergency use to aid in keeping warm a victim of an accident or other mishap.

Bearing in mind the foregoing, it is a primary object of the present invention to provide novel and improved sleeping bags which are light in weight, compressible to require little space when packed, provide great warmth when needed, enable proper venting of moisture, and be suitable for Arctic and mountaineering use.

Another primary object of the present invention, in addition to the foregoing object, is to provide such sleeping bags which are "fail-safe" and not subject to complete loss of utility due to failure of some small part.

Yet another primary object of the present invention, in addition to the foregoing objects, is the provision of such sleeping bags which are quilted in a manner to provide unusual loft and efficiency of insulation.

Yet still another primary object of the present invention, in addition to each of the foregoing objects, is the provision of such sleeping bags particularly adapted for emergency situations and capable of use in an emergency by two persons.

A still further primary object of the present invention, in addition to each of the foregoing objects, is the provision of such sleeping bags capable of being fully opened to enable an injured person to be placed therein.

A yet still further primary object of the present invention, in addition to each of the foregoing objects, is the provision of such sleeping robes characterized by a complete absence of "cold spots."

Another and yet still further primary object of the present invention, in addition to each of the foregoing objects, is the provision of such sleeping bags incorporating a maximum and generally uniform amount and thickness of insulation above the user.

It is a still further primary object of the present invention, in addition to each of the foregoing objects, to provide such sleeping bags having overlapping quilted portions.

It is another and yet still further primary object of the present invention, in addition to each of the foregoing objects, to provide novel and improved quilting structure for insulated garments and sleeping bags or robes which provide increased loft per weight of fill and reduced shifting thereof.

A yet still further primary object of the present invention, in addition to each of the foregoing objects, is the provision of novel and improved overlapping flap structure and fastening means therefor in quilted sleeping bags of superior insulating ability and reliability.

The invention resides in the combination, construction, arrangement and disposition of the various component parts and elements incorporated in improved sleeping bags or robes constructed in accordance with the principles of this invention. The present invention will be better understood and objects and important features other than those specifically enumerated above will become apparent when consideration is given to the following details and description, which when taken in conjunction with the annexed drawing describes, discloses, illustrates and shows a preferred embodiment of modification of the present invention and what is presently considered and believed to be the best mode of practicing the principles thereof. Other embodiments and modifications may be suggested to those having the benefit of the teachings herein, and such other embodiments or modifications are intended to be reserved especially as they fall within the scope and spirit of the subjoined claims.

IN THE DRAWING

FIG. 1 is a top plan view of a sleeping bag constructed in accordance with the present invention;

FIG. 2 is a partial view similar to FIG. 1 illustrating the lower portion of the bag partially opened;

FIG. 3 is an enlarged cross-sectional illustration taken along line 3--3 of FIG. 1;

FIG. 4 is an enlarged cross-sectional illustration taken along line 4--4 of FIG. 1;

FIG. 5 is a cross-sectional view similar to FIG. 3 illustrating the bag assembled in an alternative configuration; and

FIG. 6 is a cross-sectional illustration on a smaller scale similar to FIG. 3 showing another configuration thereof.

With reference now to the drawing, there is shown and illustrated a sleeping bag constructed in accordance with the principles of the present invention and designated generally by the reference character 10 which is of a quilted construction which may be fabricated of an outer fabric layer 12, inner fabric layer 14 and a pair of baffle fabric layers 16 which divide the space between the outer fabric layer 12 and the inner fabric layer 14 into a plurality of tubes which may be filled with a compressible fill material 18 to provide a lofting thereof and maintain a separation between the outer fabric layer 12 and the inner fabric layer 14.

As has long been realized, dry air is an excellent thermal insulator against transfer of heat through conduction. Dry air, however, unless restrained against circulation is a fairly good transfer medium for heat through convection. At body temperatures and below, the transfer of heat through dry air by radiation between the inner and outer fabric panels 14 and 12, respectively, is negligible. Hence, the most effective insulation for a sleeping bag or other similar construction is to provide a trapped large mass of air between the fabric layers and then prevent the transfer of heat therewithin by convection. It has been found that fluffy fill materials between the fabric layers ideally fulfill these requirements. While various fill materials may be utilized, and while where weight and bulk are not of prime importance there are many excellent artificial fibers suitable, where weight and bulk of the packed item are important, as in sleeping bags for mountaineering and backpacking use, no other material has yet been found which surpasses in desirability, Northern goose down.

While natural down has the advantage of being very easily compressed to a small fraction of its free or loose volume while yet rapidly lofting or rebounding to its free height, this ease of compressability does, to some extent, present problems. For example, because of the ease with which down is compressed, the fabric layers must be loose if the low lofting power of the down is to provide full lofting. Secondly, down insulated portions under a user's body would be greatly compressed so as to provide very limited insulation ability. Accordingly, in winter backpacking and Alpine usage, a down sleeping bag is ordinarily used in combination with a waterproof air mattress and/or closed cell foam mattress pad to provide insulation from the ground. Hence, only a small amount of down is ordinarily necessary in the portion of the sleeping bag upon which the user will lie although heretofore sleeping bags have ordinarily been made with equal quantities of down throughout substantially all portions thereof.

Since, as heretofore pointed out, the air between the outer and inner fabric layers 12 and 14 is actually the medium which performs the insulation, the filling being primarily to support the outer and inner fabric layers 12 and 14 apart and to preclude the movement due to convection of the air therebetween, the primary function of the inner baffle material 16 is to confine the down to a desired location and prevent shifting thereof so as to enable the down to most fully fill the space between the outer and inner fabric layers 12 and 14. Heretofore, in order to provide a maximum lofting or separation of fabric layers 12 and 14, it has been thought advantageous to provide the baffle tubes as large as possible so as to provide minimal restriction to the free lofting of the down. However, in accordance with the present invention, substantially smaller tubes are utilized in a plurality of layers so as to enable control of the down position to be more fully accomplished and as an aid in precluding the clumping of down in large masses with substantial free space between such masses. In other words, it has been found that the use of smaller tubes, being more numerous and in multiple layers prevents the shifting of the down and provides more efficient utilization thereof. While the baffle material 16 does add some small measure of weight to the finished bag, the additional loft and warmth that can be attained thereby due to the ability to control the down position more accurately has been found to provide such an exceptional loft and warmth as to offset the slight additional weight. Similarly, the slight additional cost of the baffle material and labor involved in manufacturing a sleeping bag in accordance with the present invention has been found to be sufficiently offset by the increased loft capable of being achieved with a given quantity of down inasmuch as good quality down is expensive.

Hence, in accordance with the present invention, the baffle material 16 comprises two layers thereof alternately sewn to each other, as by means of stitching 20 and to the outer or inner layer of fabric, respectively, as by means of stitching 22 so as to effectively provide alternating outer and inner generally triangular down tubes 24 and generally square central down tubes 26.

As heretofore pointed out, since down is ordinarily very easily compressed by body weight, although it has not been generally recognized, excessive amounts of down in the portions of the sleeping bag upon which the user will be lying do not add any substantial amount of insulation thereto but, rather, all such additional down merely adds to the cost and weight of the bag without providing any advantages. In accordance with the present invention, therefore, substantial additional quantities of down are utilized in the portions of the sleeping bag designed to be positioned above the user's body and, in addition thereto, additional layers of material are provided to control the down distribution and enable the full lofting power of such additional down to be efficiently and effectively utilized for providing increased loft and warmth. In accordance with the present invention, therefore, the portions of the sleeping bag designed to cover the user's body may comprise a pair of overlapping layers or flaps 28 and 30 each of which, in the uncompressed configuration has a thickness equal to the uncompressed configuration of the lower portion 32 upon which the user lies. Each of the portions 28, 30 and 32 may be quilted with the multiple baffle layers as heretofore described in detail and as shown in detail in FIG. 5. Hence, when in use, a very high loft of sleeping bag above the user may be achieved utilized a nominal quantity of down and without substantially increasing the weight above that of conventionally constructed sleeping bags and, in fact, with substantially less total weight than would be required to provide a similar degree of loft and warmth utilizing conventional sleeping bag constructions.

Means, including an inner zipper 34 and an outer zipper 36 may be used to secure the bag in the desired configuration with the inner flap 28 and the outer flap 30 positioned as desired. The zippers 34 and 36 are preferably of a full length, full separating, double slider variety for maximum utility and to enable the bag to be vented during less severe weather and fully closed during more severe weather as required. Furthermore, the use of such zippers enables the bag to be opened substantially flat for airing of the sleeping bag, to enable, in an emergency, an injured person to be easily wrapped up therein and the bag to be opened into an alternative configuration, as shown in FIG. 5, with the flaps 28 and 30 being in general alignment with one another, rather than being superposed one above the other, to enable the sleeping bag to be utilized, in an emergency, by two people.

A drawstring 38 may be provided at the upper edge of the bag, as by passing through a tunnel provided thereat, to enable the upper end of the bag to be gathered, as shown, to form a hood which may be closely fitted around the sleeper's face, when desired, for maximum warmth.

While many materials may be utilized for the outer and inner layers 12 and 14, as well as for the baffle material 16, preferably the outer and inner layers 12 and 14 comprise a thin, strong, water-repellent and easily cleanable material such as cotton balloon cloth or ripstop nylon while the baffle layer 16 may comprise a material which need not be downproof to which, preferably, down tends to adhere slightly so as to aid in controlling down shifting, such as nylon marquisette.

While the various dimensions of the bag constructed in accordance with the present invention will, obviously, depend upon the size of the person for whom the bag is designed, it has been found that a length of approximately 72 inches is sufficient for most individuals, with the bag in the configuration shown in FIGS. 1 and 3 having a width across the shoulders of approximately 30 inches and a width at the feet of 21 inches and with the outer flap 12 being approximately 18 inches in width at the shoulders. When so dimensioned, when the bag is assembled as shown in FIG. 5, the bag will provide a width across the shoulders of approximately 40 inches and a width across the feet of approximately 30 inches which, it will be readily understood, would be in general sufficient for two people under emergency conditions.

The zipper 36, as well as the zipper 34 are preferably of the full-separating, double-slider variety, enabling the zippers to be opened from either direction so that, in less severe weather, the bag 10 can be vented from the foot region, in addition to being unzipped from the head region. Moreover, each of the zippers 34 and 36 are preferably secured with the outer and inner layers of fabric 12 and 14 in a manner hereinafter described such that the stitching thereof does not adversely affect the insulation provided by the fill material 18. In accordance with this criteria, one half of each of the zippers 34 and 36 may be sewn, as by means of stitching 40 with the inner and outer fabric layers 14 and 12, respectively, in spaced apart relationship to the respective edge of the bag. The other half of each of the zippers 34 and 36 may be secured with the inner and outer layers, respectively, in spaced apart relationship to the respective edge of the bag as by means of stitching 42. In this way, the stitching 40 and 42 does not tend to compress any fill 18 and no tension is applied to the edge portions of the flaps which would tend to compress the edge portions, and full loft is maintained throughout the entire bag, without loss of loft at the edges as would occur with the zipper secured directly thereto.

To further prevent any draft, there may be provided a down-filled tube or flap 46 extending along the inner edge of the sleeping bag generally adjacent the zipper 34.

As heretofore pointed out, both sides of each of the zippers 34 and 36 are preferably sewn or otherwise fastened to only one of the inner and outer fabric layers, respectively, so as to affect the lofting of the fill minimally. However, and with reference now to FIG. 6, a somewhat similar effect may be produced by making the flaps wider and securing the zippers to the edges thereof, as shown, so that the portion thereof unaffected by the zippers is as wide as the flaps of the version of FIGS. 1-5.

While the invention has been described, disclosed, illustrated and shown in terms of an embodiment or modification which it has assumed in practice, the scope of the invention should not be deemed to be limited by the precise embodiments or modifications herein described, disclosed, illustrated or shown, such other embodiments or modifications as may be suggested to those having the benefit of the teachings herein, being intended to be reserved especially as they fall within the scope and spirit of the claims here appended.

Claims

What is claimed is:

1. Sleeping bag for providing high efficiency of insulation comprising, in combination, outer fabric layer means, inner fabric layer means, baffle fabric means securing the outer and inner fabric layer means together and providing a substantially uniform maximum spacing therebetween, resilient fill means disposed between said outer and inner fabric layer means for providing loft and separation therebetween and means for selectively securing one lengthwise edge portion of said bag superposed relative an other lengthwise edge portion thereof to define overlapping inner and outer flaps with the lengthwise edge of said inner flap being secured only with said inner fabric layer and the lengthwise edge of said outer flap being secured only with said outer fabric layer so that said flaps are not compressed by said securing means and said flaps are therefore of substantially uniform thickness and reduced thickness regions are effectively prevented.

2. Sleeping bag defined in claim 8 wherein said securing means is further constructed and arranged to enable, particularly in an emergency, the overlapping layers to be disposed in generally side-by-side relationship to enable the bag to be extended to provide a covering usable by more than one person.

3. Sleeping bag defined in claim 1 wherein said securing means comprises an outer zipper, one-half of which is secured with an edge portion of said bag with the other half thereof being secured with only the outer fabric means along a line spaced apart from the other edge of said bag a distance equal to the desired overlap and an inner zipper one-half of which is secured with the inner fabric layer means along a location spaced apart from said first-mentioned edge a distance substantially equal to the desired overlap and the other half of which is secured generally adjacent said other edge.

4. Sleeping bag defined in claim 3 wherein each of said zippers is of the full separating variety.

5. Sleeping bag defined in claim 4 wherein each of said zippers is of the double slider variety.

6. Sleeping bag defined in claim 5 further comprising a filled tube secured with said other edge of said sleeping bag for underlying said second-mentioned zipper and closing the resultant seam.

7. Sleeping bag defined in claim 1 wherein said baffle defining means comprises a pair of baffle fabric layers secured, alternately, with the outer and inner fabric layer means and with each other to form a plurality of overlapping tubes each containing a portion of said resilient fill to define three substantially independently quilted layers with the quilting thereof being staggered to provide high loft and uniformity of insulation.

8. Sleeping bag defined in claim 1 wherein said outer and inner flaps are of sufficient width as to substantially completely overlie and cover a person disposed within the bag, defining a high uniform loft double resilient layer of insulation above such person and a single resilient layer of insulation beneath such person to thereby provide maximum warmth per unit of insulation fill.

9. Sleeping bag defined in claim 1 wherein said securing means comprises first lengthwise extensive separable fastener assembly means for selectively securing the lengthwise edge portion of said inner flap with said inner fabric layer in spaced apart relation to the lengthwise edge portion of said outer flap and second separable fastener assembly means for selectively securing the lengthwise edge portion of said outer flap with said outer fabric layer in spaced apart relation to the lengthwise edge portion of said inner flap.

10. Sleeping bag defined in claim 9 wherein at least one of said separable fastener assembly means is secured to the respective flap edge portion in spaced apart relationship to the respective lengthwise edge so that edgewise pulling and tapering of the lofted insulation is substantially precluded.