as shown in fig1 a hammock 10 comprises a bed 12 , an insect net 14 , which is located above bed 12 and is attached along its edge 16 to longitudinal sides 18 of bed 12 . each end 20 of the bed 12 is joined with a suspending rope 22 to a spaced anchor 24 such as a tree . a canopy 26 overhangs the insect net 14 . bed 12 , dimensioned to provide accommodation for one or more persons , is made from a substantially rectangular sheet 23 ( see fig3 ) 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 material with similar qualities is used . an entrance slit 30 , situated in the same vertical plane as bed 12 &# 39 ; s longitudinal axis of symmetry a , extends from one of the short sides 32 of a substantially rectangular sheet 28 to a point short of the center of symmetry of bed 12 . the short side 32 , opposite the entrance slit 30 , of rectangular sheet 28 ( see fig4 to 9 ) is folded several times parallel to the longitudinal axis a of sheet 28 . the first fold of two layers of material is made towards the longitudinal axis of sheet 28 ( see fig5 ). then , in the same manner , rectangular sheet 28 is folded in four layers ( fig6 ), then in eight layers ( fig7 ) and then , sixteen layers ( fig8 ). finally , each bundle of sixteen layers is folded together to form one bundle of gathered folds 33 ( thirty - two layers of material ), which is held by a clamp 34 ( fig9 ) and fused by heat or bonded by an adhesive . then , one or more holes 36 ( fig1 ) are cut or obtained by melting an aperture through the final bundle . a grommet 38 is provided for each hole 36 . alternatively , an accordion - type of folding can be used . attachment of each bundle of folds 33 to each suspending rope 22 is achieved by joining a suspending rope 22 directly to its respective bundle 33 with a knot . at the short side 32 , corresponding to entrance slit 30 , the process of folding is somewhat different , including an additional set of folds which provide a self - closing entrance slit 30 . this self - closing is activated and maintained by the weight of the occupant . here , the sequence of folding is the following : edges 40 of entrance slit 30 ( fig3 ), close to the corresponding short side 32 , are folded together several times and held in place . next , one follows the same operational steps ( fig4 to 9 ), described for short side 32 , opposite to entrance slit 30 . this folding , as described , of edges 40 , prior to the folding of short side 32 , produces , under the weight of the occupant , the self - closing of entrance slit 30 . the operation of the entrance through slit 30 takes place as follows : the occupant either enters head first and turns around inside the hammock , or backs into the entrance slit until the back of his knees contact the low end of entrance slit 30 . then , the occupant sits down on bed 12 , whose 28 becomes tensioned . as the occupant reclines against bed 12 and , as he lifts his legs off the ground , his entire weight is transmitted to bed 12 . lastly , the occupant lifts his legs through entrance slit 30 , which closes , providing a bug - proof environment . the edges 40 of entrance slit 30 are folded together and held folded by the weight of the occupant . a ridge cord 42 ( fig1 to 13 ) extends in a vertical plane which includes longitudinal axis a of bed 12 and goes through each opposite bundle of gathered folds 33 and is attached to each suspending rope 22 or , alternatively , the ridge cord 42 can be attached to at least one of holes 36 . alternatively , when no holes are used , the ridge cord 42 could be attached directly to each bundle of gathered folds . preferably , the ridge cord 42 continues beyond its points of attachment at each opposite bundle of gathered folds 33 as suspending rope 22 . in order to alter the sag of bed 12 , according to individual comfort requirements , the workable length of ridge cord 42 ( fig1 to 13 ) is adjustable by untying one end of it and retying again to a shorter or longer length . as can be seen in fig1 to 13 , three examples illustrates a comparison of different adjustments . the distance between anchors 24 is constant . on the left side of all three figures ( fig1 to 13 ), there is one vertical line which constitutes the line of reference . on the right side of all three figures are three vertical lines x , y and z . the first example ( fig1 ) is a bed 12 with a ridge cord 42 , whose workable length has been preset at the factory for the comfort requirements of an average user . notice that ridge cord 42 terminates at line x , between y and z . the second example ( fig1 ) is a of bed 12 , where ridge cord 42 terminates at line y . in this case , the workable length of ridge cord is shorter and the sag of bed 12 is increased . the third example , ( fig1 ), is a bed 12 with a longer workable ridge cord 42 . ridge cord 42 now terminates at line z . thus , its length is increased but the sag of bed 12 is reduced . alternatively , a sag adjustment device 44 ( fig1 to 17 ) is provided . it has , in the presented embodiment , an elongated form with a circular cross section and two transverse holes 46 . the ridge cord 42 passes successively through both transverse holes 46 and a slack portion 48 of ridge cord 42 is left between exit 50 of first hole 46 and entrance 532 of second transverse hole 46 . the part of ridge cord 42 , which constitutes slacked portion 48 , is wrapped , when ridge cord 42 is not under tension , one or more times around either end of the sag adjustment device 44 . the extension of slacked portion 48 and , consequently , the resulting number of added or subtracted wraps has a direct influence on the final workable length of ridge cord 42 and the corresponding amount of sag of bed 12 . the adjustment , shown in fig1 , illustrates slacked portion 48 , pre - wrapped at the factory to allow existing wraps to be unwrapped from or to allow additional wraps to be wrapped around sag adjustment device 44 . the second adjustment , shown in fig1 , illustrates sag adjustment device 44 with additional wraps of ridge cord 42 , wrapped onto device 44 by the occupant of hammock 10 , to shorten ridge cord 42 and , hence , increase the sag of bed 12 . at approximately the middle of each longitudinal side 54 of the rectangular sheet 28 , an attachment element 56 is secured . the attachment element 56 is normally provided with a grommet ( not shown ). a side adjustment cord 58 passes through the attachment element 56 . the inner end of side adjustment cord 58 can be provided with means for length adjustment for example a cord lock of known type ( not shown ). the outer end of side adjustment cord 58 is attached to a fixed element 60 . the insect net 14 is formed from a sheet of substantially lozenge shape of synthetic mesh type material . polyester or nylon are preferred . the edges 16 of the insect net 14 are attached to longitudinal edges 18 of bed 12 . when the opposite side adjustment cords 58 are outwardly stretched and the suspending ropes 22 are tensioned , the shape of bed 12 , viewed in plan , is a lozenge . the canopy 26 is cut in a lozenge form from a sheet of synthetic material such as nylon or polyester . an adjustably extendible cord 62 , for each side of canopy 26 , is attached with one side where two concurrent edges of the lozenge intersect transverse axis b . the other end of the adjustably extendible cord 62 is joined to a fixed feature 64 . each two concurrent edges of the lozenge form the sheet of canopy 26 at their point of intersection with longitudinal axis a is attached to a suspending rope 22 . each length of side adjustment cord 62 can be independently adjusted . either side of canopy 26 may be flipped over and secured to the other side , to provide coverage on one side only . from that position , both sides of canopy 26 may be rolled together and stored above ridge cord 42 and secured with a ring ( not shown ) slid from one end to the mid point of said canopy . since the invention is subject to modifications and variations , it is intended that the foregoing description and the accompanying drawings shall be interpreted as only illustrative of the invention defined by the following claims .
a hammock includes a bed made of a rectangular piece of flexible , breathable material , whose ends are gathered together and secured to ropes which can be tied to respective trees . a ridge cord extends between the gathered ends , this cord being shorter than the bed , so that the bed sags somewhat no matter how much tension is applied to the ropes . an entrance slit extending about half the length of the hammock allows one to enter from below . the hammock has a lozenge shape when it is viewed from the top and may be covered by a lozenge - shaped canopy .