in the drawings , embodiments of the invention are illustrated in a purely schematic manner with no details of the furniture included , illustrating , e . g ., the design of the support member . as mentioned above , the support member may be designed as side members and a connection device 10 , gables , frames or other fixed components and the piece of furniture may be a bed , chaise longue , divan , bench , sofa , chair , etc . these constructional elements will vary according to the furniture design and a person skilled in the art will have no trouble in adapting the inventive part to the practical use . the perspective views also illustrate only the framework which constitutes the support structure of these constructional elements and , e . g ., the actual mounting member which will hold a mattress or upholstery is not included . all such elements will naturally be incorporated by a person skilled in the art . similarly , in a number of the drawings there are only shown beam elements of the support member , since these beam elements can be incorporated in the actual support structure of the piece of furniture . alternatively , these beam elements may constitute an integrated part of the actual support structure or the mounting points may be provided directly in the support structure . all such variants are considered to be obvious to a person skilled in the art and are therefore not described in more detail herein . the adjustment device according to the invention will now be explained in more detail in connection with the schematic illustration presented in fig1 of the drawing . the drawing illustrates in a side view the invention in connection with a design of a bed base or the like , where the furniture frame or the bed frame consists of three sections or parts , r which is the back member , s which is the seat member and f which is the foot or leg member of the bed frame . each of these three parts is equipped with a transverse axis or axis journals , as illustrated in fig8 and 9 . the axis journals for the back member r are designated 2 , the axis journals for the seat member are designated 3 and the axis journals for the leg member f are designated 5 . the parts of the frame are hinged or linked to one another by means of hinged joints which again are best illustrated in fig8 and 9 , in which they are designated 1 and 4 respectively . during angular adjustment of the parts r , s and f in relation to one another , the parts will rotate about the linkage points 1 and 4 , while the axis journal connection to the support member remains located in the same plane . in fig8 and 9 the support member is designated a and b respectively , and the attachment or displacement areas for the axis journals are designated 11 , 12 and 13 . it can be seen from fig8 and 9 that the axis journals 3 and 5 have displacement possibilities in the slot - shaped openings , while the back member &# 39 ; s axis journal 2 has a fixed mounting . the distance between axis journals , i . e . the fulcrum for the individual parts and the articulation between the parts determines the relative pattern of movement between the parts . these distances , i . e . the ratio between the distances between fulcrum and linkage point for back member r and seat member s are selected in such a manner that an infinitely variable adjustment of between 180 ° and 90 ° can be performed of the angle between seat member and back member . these two extreme positions are illustrated in fig1 the position illustrated by a broken line showing an angular adjustment of 90 ° between the parts r and s . by means of this movement from the position illustrated by solid lines to the position illustrated by broken lines , the mounting point 2 for the back member will remain fixed , while the mounting point for the seat member will be moved towards the back member , while at all times remaining located in the plane of the bed frame . this adjustment is illustrated in more detail in fig2 and 3 . here it can be seen that the mounting points 2 and 3 remain located on the same plane . by means of this displacement of the back member to an upright position , the seat member s , via the joint 4 , will also influence the leg member f , which will be pulled along by the movement of the seat member . the joint 4 will thereby be pulled in the direction towards the back member and lifted slightly above the bed plane . at the same time , the mounting 5 will move in the groove 13 , also in the direction towards the back member , thereby controlling the angular movement of the foot member . the length ratio between the slots 12 and 13 is preferably selected so that the foot member or the leg member will fall about an angle between 4 ° and 22 °, depending on where on the leg or foot member the suspension point 5 is located . in fig1 and 4 - 6 , this movement is indicated very prominently for illustrative reasons , but it may , of course , also be different to that which is shown in the figures . the movement mechanism for the foot member is illustrated on a larger scale in fig4 - 6 . in order to perform the angular adjustment of the back member in the simplest possible way , on the underside of the back member r , there is rigidly fastened an arm piece or a lever 6 , which is also illustrated in fig8 and 9 . between this lever and a point on the support member or another attachment point there may be provided a pneumatic cylinder or an electrical actuator which , via the lever 6 , provides for the angular adjustment and the locking of the back member r and thereby normally of all parts of the construction . fig7 illustrates the adjustment device for the invention employed in a chair . the design differs from that illustrated in fig1 only in that the leg member f has been removed . fig8 a / b and 9 a / b illustrate the use of two different support members , fig8 b showing a support member a which is intended for mounting in a bed frame or the like while fig9 b illustrates a design where the support member b is equipped with legs , i . e ., designed as a chassis . in the design in fig8 b it will be the support member a with the parts r , s and f which are tilted . in a design with legs , as illustrated in fig9 b , it will also be possible to establish a tilting function . the tilting function will be particularly relevant , e . g ., in connection with hospital or nursing home beds . fig1 also illustrates in a purely schematic form the said tilting movement for the support member , where the whole piece of furniture or the adjustable frame can be tilted , e . g ., between the positions 8 and 9 in relation to the normal position 7 , the settings 8 and 9 corresponding to angular adjustments of ± 12 °. it should be pointed out that the angular range may be both smaller and greater , and also different in the two directions , e . g ., only ± 12 °. in fig1 - 17 , four further alternative embodiments of the invention are illustrated . in these figures , the same reference numerals are also employed as in the preceding examples , but in addition , in the schematic views , there are inserted reference numerals illustrating the connection with the support member , even though the support member is not shown in these figures . fig1 a and 10b and fig1 illustrate a design in which the fulcrum 3 of the seat member s coincides with the fulcrum 5 of the foot member f and where this common fulcrum 3 , 5 also coincides with the link or the hinge 4 between the seat member and the foot member . the common fulcrum 3 , 5 is provided at the lower end of an arm or extension 5 ′ of the foot member f . the arm 5 ′ is rotatable about a point 4 ′ which is located above the plane of the frame . thus in this variant the foot member f is extended with a fixed angular extension 5 ′ from the hinged joint 3 between the seat member s and the foot member f , the angular extension 5 ′ thereby acting as a lever or supporting stay which is attached / mounted rotating in the fixed point 4 ′ in the support member . this point in the support member is designated 12 and is located above the joint 4 between the seat member and the foot member . during an angular alteration of the back member r the link axle 1 between the back member r and the seat member s will move in a circular arc , outwardly from the , plane of the frame , round the back &# 39 ; s suspension axis 2 , as illustrated in fig1 b . such an angular alteration of the back member r moves the seat member s , which in turn moves the linkage 3 between the seat member s and the foot member f in a circular arc round the rotating axis 4 ′ for the arm 5 ′. the design permits the angle between back member and seat member to be adjusted between 180 ° and up to 90 °, while at the same time the angle between seat member and foot member is adjusted between 180 ° and up to 300 ° or more . the solution is particularly suitable for a reclining chair or another type of chair , in which the foot member in the sitting position should be able to or can be pulled some distance under the seat member . the angle between the seat member and the foot member will be dependent on the distances between 4 ′ and 3 relative to the distance between 2 and 1 and / or the angle for the extension of the foot member , i . e ., the arm member 5 ′. this extension 5 ′ does not necessarily have to have the angle illustrated , but an angular extension will bring the foot member under the seat member earlier than if the lever 5 ′ is designed straight . a further variant of the invention is illustrated in fig1 a , b and fig1 . this variant consists in the seat member s moving or sliding along a fixed axle or fulcrum 3 , which is attached to the support member at point 12 , but which , if so desired , can be moved in the support member &# 39 ; s longitudinal direction , as illustrated by the double arrow 12 a . a similar principle may be introduced for the foot member f , which moves or slides along a fixed axle 5 attached to the support member at point 13 . this fulcrum 5 may also advantageously be moved in the support member &# 39 ; s longitudinal direction as indicated by the double arrow 13 a . in order to facilitate the movement the rotating axles 3 and 5 can rotate or roll . this principle makes it possible to perform an infinitely variable adjustment of the angle between back member and seat member between 180 ° and 90 °, thereby adjusting the angle between seat member and foot member between 180 ′ and up to approximately 220 °. on condition that the angle between back member and seat member is not equal to 180 °, it will be possible to set altered angles for seat member and / or foot member separately without changing the back angle . similarly , it will be possible to alter the angle between seat member and foot member , even though the seat member does not move when the angle between seat member and foot member is different from 180 °. in a further variant illustrated in fig1 a , 14 b , and 15 , the rotating pin 3 of the seat member s is rotatably attached either to the central area of the seat member as illustrated in fig1 and 15 , in the seat member closer to the articulated hinge 4 , or in the articulated hinge 4 , as illustrated in fig1 and 17 . from the seat member &# 39 ; s rotating pin 3 a lever 14 descends to a fixed , rotatable attachment point in the support member at point 12 . in fig1 and 16 this fulcrum is designated 16 ′. the lever 14 , which is rotated about fixed points both in the seat member s and the support member , will then act as a pendulum when the back member changes position , pulling along with it the seat member s . the length of the lever 14 between seat member s and support member and the location of the attachment points 3 and 16 ′ will thus determine the seat &# 39 ; s angle together with the curved movement of the link . the same principle may then also be introduced for the foot member , the foot member &# 39 ; s rotating pin 5 being rotatably attached at a suitable point on the foot member . the rotating pin 5 is connected via an arm 15 to a fixed , but rotatable attachment 16 in the support member at point 13 . the lever 15 , which rotates about fixed fulcrums both in the foot member and the support member , will thereby act as a pendulum when the back member r changes position , pulling along with it the seat member s and the foot member . the length of the lever 15 and the location thereof will then determine the angle together with the curved movement . it should be noted that it will also be possible to employ variants of the illustrated embodiments , since , e . g ., a mechanism from one embodiment may be combined with elements from another embodiment . all such combinations are intended to fall within the scope of the invention . reference is also made to a special modification according to the invention , illustrated in fig1 and 19 , where the back member is equipped with an extra link which forms a neck cushion or neck support , in order to provide a more comfortable position when the piece of furniture is employed in a sitting position or semi - sitting position . in norwegian patent no . 176 384 ( owner ekornes ), a neck support device is described for an adjustable chair , where the neck support is automatically raised when the chair is lowered into a reclining position . according to a feature of the invention , a similar device may also be employed on the back member according to the invention , but arranged in such a manner that the neck support is pulled forward when the back is raised , i . e ., with the result that it has the opposite effect to that which is described in the ekornes patent . it is such a design which is illustrated in fig1 and 19 . it will also be possible to employ other means for adjusting the neck support . the mechanism which is employed in this connection is described in the patent and in the present invention is mounted on the back member , only acting in the opposite direction . with regard to the description thereof , reference is made to the above - mentioned application . in the drawings the invention is only illustrated by means of principle drawings , and it should be quite obvious that it will be possible to design the individual parts of the frame in many different ways , with many different types of support elements . these features do not constitute components of the actual invention and are therefore not illustdrated in more detail . the use of different possibilities for variation will be obvious to a person skilled in the art . joint and axle mounting are also indicated purely in principle . it will be possible for a person skilled in the art to vary these elements too , e . g ., by introducing an extra degree of freedom for one or more axles . it may also be conceivable that a frame of this kind may be designed with more parts , and this too will fall within the scope of the invention .