fig1 through 5 and 13 and 14 depict an anchor nut 10 in accordance with a first embodiment of the present invention . fig1 and 14 show nut 10 inserted through and in locked engagement with the edge of a mounting hole 12 of rectangular ( square ) configuration through the lower side of a workpiece 14 which , for example , may be a piece of sheetmetal forming part of the leg or bottom of an object such as a domestic appliance . fig1 also shows nut 10 engaged by a threaded member , such as an adjustable mounting foot 16 having a head 18 and a threaded shank 20 . in fig1 , a broken line 22 designates a pallet having a hole 24 therethrough through which mounting foot 16 extends to illustrate an arrangement wherein foot 16 secures the pallet against anchor nut 10 and to the bottom of the appliance for shipment . it is to be understood that pallet 22 could be omitted and foot 16 could be fully screwed into nut 10 so that head 18 bears against the nut and is out of the way during shipment . as fig1 through 5 show , anchor nut 10 comprises two sections or nut - halves 24 , 26 which are connected together by a thin flexible web or hinge 28 which enables the two sections to be moved from the unfolded position ( in which they are molded ), shown in fig1 through 4 , to the folded position ready for insertion , as shown in fig5 . when so folded , sections 24 and 26 define a screw - receiving bore 29 , as fig5 shows . nut sections 24 and 26 are mirror images of each other except that , for alignment purposes , section 24 comprises a pair of hemisperical indentations 30 for receiving a pair of hemispherical projections 32 on section 26 . since the sections 24 and 26 are substantially identical , only section 24 is hereinafter described in detail . section 24 comprises a semi - cylindrical head portion 34 from which a rectangular tapered shank portion 35 extends . shank portion 35 is divided by a wedge - shaped slot 38 into resiliently movable bifurcations or legs 35a and 35b which can be flexed , as hereinafter explained , in the direction of the arrow a in fig2 . shank portion 35 is provided with two slots or grooves 40 on opposite sides thereof in the region where shank portion 35 joins head portion 34 and these grooves 40 and adjacent shoulders 41 serve as a locking or latching means for gripping the edge of the hole 12 in workpiece 14 , as fig1 and 14 show . section 24 of anchor nut 10 comprises inside and outside surfaces 42 and 44 , respectively , and also comprises top and bottom surfaces 46 and 48 , respectively . inside surface 42 is provided with a nearly semi - cylindrical indentation or depression 50 which extends between and through top surface 46 and bottom surface 48 . depression 50 is divided into four regions , as follows , as shown in fig2 : a threaded head region 50a , an unthreaded intermediate region 50b , a threaded region 50c on leg 35a , and a threaded region 50d on leg 35b . prior to insertion of screw 16 , the legs 35a and 35b and the threaded regions have the relationship shown in fig2 but after screw insertion the legs 35a and 35b flex outwardly to the position shown in fig1 with the following effect : the shoulders 41 of the grooves 40 more firmly entrap or engage workpiece 14 ; the depression 50 assumes a substantially semi - cylindrical ( although threaded ) configuration ; and the threaded regions 50c and 50d on legs 35a and 35b , respectively , align with the threaded head region 50a . the unthreaded intermediate region 50b allows for such threaded alignment . it is to be noted that the legs 35a and 35b of each section 24 and 26 are tapered inwardly toward each other , as fig2 shows , when those legs are in relaxed condition and , therefore , the threads 50c and 50d on each leg 35a and 35b are also tapered toward each other and out of registry . the threads 50c and 50d become properly aligned when the end of screw 16 , already engaged with the threads 50a , crosses the unthreaded intermediate region 50b and starts to engage the threads 50c and 50d but , before being able to do so , first causes the legs 35a and 35b to spread apart . the insertion end of depression 50 is provided with a chamfered surface 52 to facilitate screw insertion into the bore 29 defined by the two mating depressions 50 . the head portion 34 of nut section 24 is provided with recesses 54 separated by walls 56 which extend inwardly ( see fig3 and 4 ) which reduce the amount of plastic material required to fabricate the nut without sacrificing rigidity or strength . anchor nut 10 is employed as follows . assume initially that nut 10 is disposed as shown in fig1 through 4 . the nut - halves or sections 24 and 26 are then swung toward each other on hinge 28 until they assume the condition shown in fig5 . proper mating and alignment of the sections 24 and 26 is accomplished by engagement of the projections 32 with the indentations 30 . in this condition , the shank portion 35 of nut 10 is inserted into and through mounting hole 12 in workpiece 14 , as fig1 shows . the wedge - shaped slots 38 allow the pair of legs 35a and the pair of legs 35b to move toward each other as tapered shank portion 35 is pushed into mounting hole 12 . thus , the distance between the pair of shoulders 41 is reduced sufficiently to enable the shoulders to move through hole 12 , whereupon the pairs of legs 35a and 35b spring outwardly to the position shown in fig1 . this enables the opposite edges of the workpiece 14 adjacent hole 12 to engage the grooves 40 in locking relationship . at this point , the threaded member or screw 16 is screwed into that portion of bore 29 defined by the two mating threaded head regions 50a of the head portions 34 of the sections 24 and 26 . the lead end of screw 16 then traverses the unthreaded section of bore 29 defined by the mating pair of unthreaded intermediate regions 50b . the lead end of screw 16 engages four tapered threaded regions 50c and 50d and by forcing apart the pair of legs 35a and the pair of legs 35b in the outward direction causes the screw threads on the four legs 35a and 35b to become properly aligned with each other and with the screw 16 , as fig1 shows . screw 16 is driven into anchor nut 10 to whatever extent is necessary or desirable . when screw 16 is in place , anchor nut 10 cannot be withdrawn from hole 12 in workpiece 14 because of the fact that the semi - cylindrical head portions 34 bear against one side of workpiece 14 and the shoulders 41 bear against the opposite side of the workpiece , as fig1 shows . however , if screw 16 is unscrewed from anchor nut 10 , either completely or at least to the point where threaded screw shank 20 is disengaged from the four threaded regions 50c and 50d , then the pairs of legs 35a and 35b move toward each other to the position shown in fig1 and can then be squeezed even closer together manually until the distance between the shoulders 41 is less than the diameter of hole 12 in the same direction , whereupon nut 10 can be withdrawn from hole 12 . after withdrawal , anchor nut 10 tends to resume the unfolded condition shown in fig1 through 4 . fig6 through 12 depict an anchor nut 110 in accordance with a second embodiment of the present invention . fig1 shows nut 110 inserted through and in locked engagement with the edge of a mounting hole 12 of rectangular ( square ) configuration through the lower side of workpiece 14 . as fig6 through 12 show , anchor nut 110 comprises two sections or nut - halves 124 , 126 which are connected together by a thin flexible web or hinge 128 which enables the two sections to be moved from the unfolded position ( in which they are molded ), shown in fig6 through 10 , to the folded position ready for insertion , as shown in fig1 . when so folded , sections 124 and 126 define a screw - receiving bore 129 , as fig1 shows . nut sections 124 and 126 are mirror images of each other except that , for alignment purposes , section 124 comprises a pair of hemispherical indentations 130 for receiving a pair of hemispherical projections 132 on section 126 . since the sections 124 and 126 are substantially identical , only section 124 is hereinafter described in detail . section 124 comprises a semi - cylindrical head portion 134 from which a rectangular shank portion 135 extends . shank portion 135 is provided with two slots or grooves 140 on two opposite sides thereof intermediate the ends of shank portion 135 . these grooves 140 accommodate resilient movable or flexible tabs 143 which serve as a locking or latching means for gripping the edge of the hole 12 in workpiece 14 , as fig1 shows . each tab 143 is integrally formed with shank portion 135 and extends outwardly therefrom . section 124 of anchor nut 110 comprises inside and outside surfaces 142 and 144 , respectively , and also comprises top and bottom surfaces 146 and 148 , respectively . inside surface 142 is provided with a semi - cylindrical indentation or depression 150 which extends between and through top surface 146 and bottom surface 148 and which is provided with a threaded head region 150a . the insertion end of depression 150 is provided with a chamfered surface 152 to facilitate screw insertion into the bore 129 defined by the two mating depressions 150 . the head portions 134 of nut sections 124 is provided with recesses 154 separated by walls 156 which extend inwardly ( see fig7 and 10 ) which reduce the amount of plastic material required to fabricate the nut without sacrificing rigidity or strength . anchor nut 110 is employed in either one of two ways as follows . assume initially that nut 110 is disposed as shown in fig6 through 10 . in the first manner of usage the nut - halves or sections 124 and 126 are then swung toward each other on hinge 128 until they assume the condition shown in fig1 . proper mating and alignment of the sections 124 and 126 is accomplished by engagement of the projections 132 with the indentations 130 . in this condition , the shank portion 135 of nut 110 is inserted into and through mounting hole 12 in workpiece 14 , as fig1 shows . the tabs 143 move toward each other into the grooves 140 as shank portion 135 is pushed into mounting hole 12 . thus , the distance between the outside surfaces of the pair of tabs 143 is reduced sufficiently to enable the shank to move through hole 12 , whereupon the pair of tabs 143 spring outwardly to the position shown in fig1 . this enables the opposite edges of the workpiece 14 adjacent hole 12 to engage the shoulders 141 in locking relationship . at this point , the threaded member or screw 16 is screwed into threaded bore 129 . screw 16 is driven into anchor nut 110 to whatever extent is necessary or desirable . in the second manner of usage hereinbefore referred to , the nut - halves 124 and 126 are folded around the threaded shank 20 of screw 16 at some preferred location and the anchor nut 110 with the screw 16 already in place therein is inserted into hole 12 in the same manner as hereinbefore described . anchor nut 110 cannot be withdrawn from hole 12 in workpiece 14 because of the fact that the semi - cylindrical head portions 134 bear against one side of workpiece 14 and the tabs 143 bear against the opposite side of the workpiece , as fig1 shows . however , the tabs 143 can be squeezed closer together manually into the grooves 140 whereupon nut 110 can be withdrawn from hole 12 . after withdrawal , anchor nut 110 tends to resume the unfolded condition shown in fig6 through 10 . fig1 through 21 depict an anchor nut 210 in accordance with a third embodiment of the present invention . fig2 shows nut 210 inserted through an in lock engagement with the edge of a mounting hole 12 of rectangular ( square ) configuration through the lower side of workpiece 14 . as fig1 through 21 show , anchor nut 210 comprises two sections or nut - halves 224 , 226 which are connected together by a thin flexible web or hinge 228 which enables the two sections to be moved from the unfolded position ( in which they are molded ), shown in fig1 through 18 , to the folded position ready for insertion , as shown in fig2 . when so folded , sections 224 and 226 defined a screw - receiving bore 229 , as fig2 shows . web 228 is non - frangible . nut sections 224 and 226 are mirror images of each other except that , for alignment purposes , section 224 comprises a pair of hemispherical indentations 230 for receiving a pair of hemispherical projections 232 on section 226 . since the sections 224 and 226 are substantially identical , only section 224 is hereinafter described in detail . section 224 comprises a semi - cylindrical head portion 234 from which a rectangular shank portion 235 extends . section 224 of anchor nut 210 comprises inside and outside surfaces 242 and 244 , respectively , and also comprises top and bottom surfaces 246 and 248 , respectively . inside surface 242 is provided with a semi - cylindrical indentation or depression 250 which extends between and through top surface 246 and bottom surface 248 and which is provided with a threaded region 250a . the head portion 234 includes an undersurface 225 and the shank portion 235 includes an outerface 227 , a first side face 229 and a second side face 231 . each side face 229 , 231 has a width w ( see fig1 ) and each side face has an integrally formed tab or projection 243 thereon which extends outwardly from its respective side face and serves as a locking or latching means for gripping the edge of the hole 12 in workpiece 14 , as fig2 shows . each projection 243 , which slopes outwardly proceeding from its respective side face 229 , 231 in a direction toward undersurface 225 of head portion 234 and terminates short of undersurface 225 so as to provide a groove 239 for receiving the hole edge , extends only about one - half the width w ( w / 2 ) across its respective side face 229 , 231 . furthermore , shank portion 235 is provided with a slot or groove 240 which extends inwardly from outer face 227 for a depth slightly greater than the width of its associated projection 243 and exits at side face 229 . slot 240 is preferably slightly longer than the associated projection 243 and has a width which is preferably slightly deeper than the maximum distance which the associated projection 243 extends from its respective side face 229 , 231 at its widest point . this enables the projection 243 to be fully depressed during insertion into or removal from hole 12 of anchor nut 210 . this construction enables solid latching of nut 210 in hole 12 , since each of the four projections 243 on nut 210 acts independently of the other . furthermore , although four independent projections 243 are provided , this is done by using a minimum amount of plastic material and the maximum material is retained at the thinnest portion of the shank wall thereby resulting in a stronger anchor nut . the insertion end of depression 250 is provided with a chamfered surface 252 to facilitate screw insertion into the bore 229 defined by the two mating depressions 250 . the head portions 234 of nut section 224 is provided with recesses 254 separated by walls 256 which extend inwardly ( see fig1 , 18 and 19 ) which reduce the amount of plastic material required to fabricate the nut without sacrificing rigidity or strength . anchor nut 210 is employed in either one of two ways as follows . assume initially that nut 210 is disposed as shown in fig1 through 19 . in the first manner of usage the nut - halves or sections 224 and 226 are then swung toward each other on hinge 228 until they assume the condition shown in fig2 . proper mating and alignment of the sections 224 and 226 is accomplished by engagement of the projections 232 with the indentations 230 . in this condition , the shank portion 235 of nut 210 is inserted into and through mounting hole 12 in workpiece 14 , as fig2 shows . the tabs 243 move toward each other into the slots 240 as shank portion 235 is pushed into mounting hole 12 . thus , the distance between the outside surfaces of the pair of tabs 243 is reduced sufficiently to enable the shank to move through a hole 12 , whereupon the pair of tabs 243 spring outwardly to the position shown in fig1 . this enables the opposite edges of a workpiece such as the workpiece 14 adjacent hole 12 to engage the shoulders 241 in locking relationship . at this point , the threaded member or screw 16 is screwed into threaded bore 229 . screw 16 is driven into anchor nut 210 to whatever extent is necessary or desirable . in the second manner of usage hereinbefore referred to , the nut - halves 224 and 226 are folded around the threaded shank 20 of screw 16 at some preferred location and the anchor nut 210 with the screw 16 already in place therein is inserted into hole 12 in the same manner as hereinbefore described . anchor nut 210 cannot be withdrawn from hole 12 in workpiece 14 because of the fact that the semi - cylindrical head portions 234 bear against one side of workpiece 14 and the tabs 243 bear against the opposite side of the workpiece , as fig2 shows . however , the tabs 243 can be squeezed closer together manually into the slots 240 whereupon nut 210 can be withdrawn from hole 12 . after withdrawal , anchor nut 210 tends to resume the unfolded condition shown in fig1 through 19 , ready for re - use . as seen in fig1 and 20 , there is 100 percent thread engagement with shank 16 for the full length of nut 210 .