fig1 shows the preferred embodiment of the vee joint , generally designated 10 , wherein the flanges 20 , 30 are hingedly connected to one another with hinge 80 so as to form a channel or trough 70 therebetween . flange 20 is connected at an angle a to flange 30 and either flange can be rotated about the hinge 80 to either increase or decrease the angle a and thereby adjust the spacing between upper edges 90 . upper edges 90 of the flanges 20 , 30 may rest upon the entire lengthwise extent of joint walls 112 ( fig3 ) when the vee joint 10 ( having a length l which is substantially the same as that entire lengthwise extent ) is in use within a joint interval 110 and may have a lip 250 as is further discussed with regard to fig5 . the first embodiment of the vee joint 10 may be formed from a single piece of inorganic material that is folded in the central portion thereof forming the two flanges 20 , 30 and angle a . as shown in fig2 and 3 , when the vee joint 10 is in use , it is placed within a joint interval 110 of a concrete floor or slab 100 and 101 where it rests upon a load transfer element or elements 160 , such as a dowel or dowels . the load transfer elements 160 may be intermittently placed throughout the floor structure to provide support to the vee joints 10 . the vee joint 10 can also be placed upon any type of slab support such as insulation , sub - grade supports , slip sheets or the like . the flanges 20 , 30 ( fig1 ) are movable toward and away from one another , and can easily be set to a specific width to accommodate various sized joints between concrete slab 100 and 101 . therefore , the wider the joint interval 110 , the wider the span of the vee joint 10 must be . they may also be enlarged or decreased in dimension “ h ” to fit into varying joint depths “ d ”. the vee joint 10 is used to support joint fill material 120 within the joint interval 110 . enough joint fill material 120 is maintained within the joint 10 so that the top of the joint fill material is the same height as the top surface 150 of the floor slabs 100 , thereby creating a constant floor surface throughout the entire floor . by maintaining a constant floor surface , erosion to the corners and edges of the floor slabs 100 , caused by heavy equipment , is minimized . due to the movable nature of the flanges 20 , 30 , when a large angle a is formed between the flanges 20 , 30 , the span that the flanges 20 , 30 will fill is greater . when a narrow joint interval 110 exists , the angle a between the flanges 20 , 30 can be reduced , thus bringing the ends 90 of the flanges 20 , 30 closer together to fill the narrower joint interval 110 . this flexible configuration of the vee joint 10 allows the installation of the vee joint 10 to be easy and expedient regardless of the size and shape of the joint interval 110 . for example , a vee joint 10 can be forced into an opening wider than its base or hinge 80 but narrower than the edges 90 of the flanges 20 , 30 when they are placed in their support position , and then the vee joint 10 is configured to fit within the joint interval 110 by spreading the flanges 20 , 30 out to their support or extended position . the flexible nature of the vee joint 10 also allows for a single size vee joint 10 to be manufactured so as to accommodate various types and sizes of joint intervals 110 , making the manufacture economical and easy . the vee joint 10 can change along with the joint 110 if the joint 110 expands or contracts during use of the floor . the vee joint 10 is designed to retain joint filler 120 above the vee joint 10 at a level even with the top surface 150 of the floor slab 100 as shown in fig3 . the configuration of the vee joint 10 behaves in a cup - like fashion catching the joint filler 120 between the flanges 20 , 30 and retaining it therein . when liquid filler is installed the flanges 20 and 30 minimize its passage beyond vee joint 10 until it hardens . when forces are applied to the top edge 140 of the joint filler 120 , the flanges 20 , 30 are forced outwardly , distributing the load against the slabs 100 and 101 and as well as onto load transfer for elements 160 . fig3 shows the hinge 80 of the vee joint 10 resting on load transfer elements 160 ( fig2 ) for support within a floor slab 100 . when in use , the upper edge 90 of each flange 20 , 30 rests against a joint wall 112 , one on each side of the joint interval 110 . with the hinge 80 and each upper edge 90 of each flange 20 , 30 supported , the joint filler 120 is prevented from moving past the vee joint 10 and being forced further within the joint interval 110 . the top edge 140 of the joint filler 120 is also maintained level with the top surface 150 of the floor slab . as shown in fig4 it is a common practice to fill the joint interval 110 with a backer element 170 that is typically a foam ( as shown ) rod which is round or oval in shape , for the purpose of minimizing passage of liquid joint filler beyond it . sand or grit fill may be used in place of the backer rod 170 . the rod 170 is not a very effective way to retain the hardened joint filler 120 within the joint interval 110 and above the load transfer device 160 because it provides little , if any , support . when a force is applied to the top edge 140 of the joint filler 120 , which is common when heavy objects such as forklifts and other vehicles drive across the top surface 150 of the floor 100 , the joint filler 120 is forced in a downward direction within the joint interval 110 . eventually , enough of the joint filler 120 is pushed deep within the joint interval 110 resulting in an open space within the joint interval at or just below the surface level 150 of the floor 100 . fig5 shows a cross - sectional view of a second embodiment of the vee joint 210 described herein . in this second embodiment , the vee joint 210 has two flanges 220 , 230 , one on each side of the vee joint 210 . each flange 220 , 230 has a connected end 280 and a free end 290 . the connected end 280 of each respective flange 220 , 230 connects the flange 220 , 230 to a central , cross member 240 forming a u - shaped vee joint 210 . the cross member 240 can be straight or curved in shape . the connected end 280 of each flange 220 , 230 is flexible so as to allow each flange 220 , 230 the ability to move in a hinged manner with respect to the cross member 240 . therefore , the flanges 220 , 230 of the second embodiment of the vee joint 210 are movable allowing the vee joint 210 to be adaptable to fit into various sizes and shapes of joint intervals 110 . the free end 290 of each flange 220 , 230 may be flared or slightly angled from the respective flange 220 , 230 forming a lip 250 thereon . the lip 250 rests against the joint walls 112 and prevents the joint filler 120 from being forced past the vee joint 210 into the joint interval 110 . each lip 250 may even be driven into the joint walls 112 by the pressure of the joint fill material 120 . although particular embodiments of the invention have been described in detail herein with reference to the accompanying drawings , it is to be understood that the invention is not limited to those precise embodiments , and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims . for example , the hinge 80 may be made of varying widths to accommodate various sized joint intervals 110 and support greater amounts of joint filler 120 therein . the vee joint 10 may be made of a single piece of material wherein the flanges and hinge are all integrally formed with one another , or the vee joint may be comprised of separate and distinct elements that have been connected together through conventional connection means .