The present invention relates to an extension table with two table top sections arranged mutually slidably, the sections being supported by side aprons, which are slidably mounted to a mounting frame and are mutually connected by a link mechanism, which can be activated by swivelling about a vertical axis for synchronous move¬ ment of the table top sections away from and towards each other; and one in a storage position under the table top placed extension leaf having a length, which corresponds to the width of the table, and the extension leaf is in that position lengthwise at least approxi¬ mately at a right angle to the intersecting edges of the table top sections, and arranged such that the extension leaf can be swivelled about a central axis in the mount¬ ing frame, so that the side edges of the extension leaf become parallel to the abutted edges of the table top sections and can be elevated to levelling with the table top when the table top sections are in their remotest position and can be closed upon the extension leaf to form an extended continuous table top.

Tables of this type are particularly known from the US-patents Nos. 1,915,346 and 1,915,437 and 2,007,475 as well as 3,294,042, where the closest known technique is considered to appear from the US-patent 2,007,475. For all four designs apply that several manual movements are required in order to extend the table and to stow the leaf away again. Standing at the end of the table it is initially required to pull the two table top sections away from each other, whereafter it is necessary to move to a position straight in front of the centre of the table to turn the extension leaf into position. Raising takes place in all circumstances by means of cooperating wedges. Raising can take place before the turning as at the construction dealt with in the US-patent 1,915,346

or after the turning has been completed. However, in all circumstances a fair amount of muscular strength is required, especially just at the peak where the movement may simultaneously release a heavy vibration in the construction. At the construction dealt with in the US-patent 3,294,042 the extension leaf is elevated by a strong spiral spring being released at the turning and pushing the extension leaf upwards to levelling with the table top. At return the extension leaf shall be pushed downwards against the spring force and be held downwards at the same time as the leaf be turned. When the exten¬ sion leaf is at level, one needs to walk from the centre to behind the end of the table to slide the table top sections together around the extension leaf. The designs are also more or less dedicated exactly to the specific type of table dealt with in the respective patent speci¬ fications, thus the construction dealt with in the US-patent 3,294,042 may only with difficulty be prac¬ ticed at other tables than tables having a leg at each corner.

From US-patent 4,494,466 a table is known having three wedge surfaces arranged in a circle and where the extension leaf at the under side is equipped with driv¬ ing wheels for rolling on the wedge surfaces. Swivelling of the extension leaf from the storage position takes place by a vertical edge of the wedge surfaces pushing at the wheels and the levelling takes place by the wedge surfaces being turned down under the wheels. The con¬ struction has the disadvantage that lowering and level¬ ling of the leaf is difficult to control as the weight of the leaf contributes to or acts against the rotation when the wheels act on the wedge surfaces. The wedge elements also result in a relatively large construction height.

The purpose of the invention is to indicate an extension table of the type mentioned in the preamble.

where extension of the table top and storage of the extension leaf can be achieved in a sole operation, and that the construction is equally usable regardless of the shape of the table top, that is to say whether the two table top sections are quadratic, rectangular, round or oval and the support construction, that is to say whether there is a table leg at each corner, a support at each end or a column at the centre. This is obtained according to the invention in a table having the subse¬ quent characteristic features, namely that it comprises a cam disc and a drive unit with operating device for rotating the cam disc about its axis and to which the link mechanism is connected, and that the extension leaf at the under side has a driving stud for engaging the cam disc such that the extension leaf rotates from the storage position to the elevating position by rotation of the cam disc as the top sections are pulled outward¬ ly, and that an elevating device is connected to the cam disc in such a manner that it abuts the under side of the extension leaf for elevating the extension leaf to the final position level with the table top, and by further rotation of the cam disc the table top sections are closed upon the extension leaf.

At this improvement the mechanical construction can be made as a separate compact unity, whereon the table top sections and the extension leaf with almost optional shape can be assembled, just as the choice of the leg construction is free. The mechanical construction can be made as a flat rectangular box only taking up negligible space in the height and does not become visible for a standing person or one who sits in the proximity of the table, just as it does not hamper those sitting at the table. The table can be extended by the extension leaf by activating the operating lever, whereby the movements take place in consistent order until the extension leaf is brought to its extended position. Storage also occurs

automatically by activating the operating lever. Turning of the cam disc can be undertaken in different ways, e.g. by a cable around the disc in a groove, a rack-and-pinion or by a small electrical motor, which pulls at the periphery of the cam disc or at the rota¬ tional axis and is operated by finger-touch at the edge of the table.

In order to allow swivelling of the extension leaf the table top sections cannot be attached to the aprons in the region of the edges facing each other and the swivelling direction of the extension leaf, whereby one corner of the table top sections is not stably sup¬ ported. This can be met with dowels and corresponding receiving holes in the facing edges of the sections and the leaf. An extra support can be obtained pursuant to the invention by placing at least one wedge element at the under side of the extension leaf and a wedge element at the upper side of the cam disc and positioned in relation to each other such that the extension leaf is elevated to firm abutment against the under side of the two table top sections in the starting position. The table top sections are in this way efficiently supported and at the same time the extension leaf is in a locking position. It is thus avoided that the extension leaf can be set in vibrations in the storage position, generating a ^■■ fluttering" as a consequence of movements in the table. The wedges are, however, placed such that the extension leaf is lowered before initiation of the other movements such that the upper side of the leaf is not scratched against the under side of the table top sec¬ tions.

In order to reduce the power for operating the table it is preferred to almost balance the weight of the extension leaf, but however, not more than the re¬ maining resultant weight is adequate to letting the leaf by its own weight go back to its lowermost position. The

balancing can preferably be made such that the rotation axis of the extension leaf supports a spring leaf which can lie in a profile under the table in its longitudinal direction.

The levelling device, which levels the extension leaf at level with the table top, can be designed in different ways, for instance it can be a swinging link suspension at the inner side of the mounting frame as indicated in the claims and exemplified in the follow¬ ing. The construction is simple and occupies only a small space, but there could also be used eccentrics, wedges or the levelling could be made on the rotation axis of the extension leaf by an electrical linear motor.

The invention shall be described closer in the following with reference to the accompanying drawing, which shows:-

Figs. 1 and la to Figs. 7 and 7a, conjugated sche¬ matic functional figures, which illustrate the function of the table according to the invention, where the table is seen from the side and from above, respectively.

Fig. 8 one end of the mechanical construction seen from above,

Fig. 9 the mechanical construction seen from above as in Fig. 8, but without sleighs which carry the table top sections and where the starting position of the rod connection (Fig. 1) is suggested by A, and the maximum pull-out position (Fig. 6) is suggested by B, and the closed position about the extension leaf (Fig. 7) is suggested by C,

Fig. 10 an enlarged cross section of the bearer of the frame and the apron.

Fig. 11 a cross section of the cam disc construc¬ tion, and where the extension leaf is elevated at the table top level.

Fig. 12 one end of the swinging link suspension to

raise and lower the extension leaf seen from the side, where the elevated position is indicated by dashed lines,

Fig. 13 a cross section of the construction shown in Fig. 12, and

Fig. 14 a longitudinal cross section of the pivot arm down under the cam disc and towards the extension leaf in the starting position.

In connection with the schematic functional figures shown in the drawings Figs. 1,1a to 7,7a, in the follow¬ ing a brief functional description shall be given of the table at its extension by an extension leaf, as the main parts of the table shall be indicated by way of intro¬ duction. The table includes a table top comprising two table top sections 2a, 2b, an extension leaf 4, a sup¬ port structure 6 with legs and a mechanical construction 8, whereon the other main parts are mounted.

In the starting position of the table, that is to say the closed position of the table, the two table top sections are completely pushed together, and the exten¬ sion leaf is in its storage position under the table top with the upper side in firm engagement against the under side of the table top. The extension leaf, which has a length corresponding to the width of the table top, lies in the longitudinal direction of the table in the storage position, see Figs, l and la.

The slot at the side side is covered by cover plates or a curtain of vertical strips such that the slot is concealed, preventing a hand or fingers acci¬ dentally getting caught. However, at swivelling of the extension leaf the cover plates or curtain slide away.

When the table is to be extended by the extension leaf, an operating handle 10 is pulled at the table end, releasing a subsequent number of movements of the exten¬ sion leaf and the two table top sections, until the table is extended.

The movements are initiated by lowering the exten¬ sion leaf 4 a short distance, such that it is clear of the under side of the table top, see Figs. 2 and 2a.

As it appears from Figs. 3 and 3a hereafter a syn¬ chronous sliding occurs of the two table top sections 2a, 2b away from each other.

Immediately upon this the extension leaf 4 ini¬ tiates a 45° rotation about a vertical axis in the centre of the table, see Figs. 4 and 4a.

The rotation movement is ended when the extension leaf is turned such that it stands transversely to the table; at the same time the two table top sections are pushed so far apart corresponding to the width of the extension leaf, see Figs. 5 and 5a.

Upon the extension leaf being turned in position transversely to the table it is raised to level with the table top at the same time as the two table top sections are displaced an additional short distance away from each other, see Figs. 6 and 6a.

In the last movement the two table top sections are pulled together against the extension leaf, and the table top is now extended by the extension leaf, see Figs. 7 and 7a.

When the table shall bee shortened the movements occur in reverse sequence, that is to say the two table top sections are pushed a short distance from each other, whereafter the extension leaf is lowered and the table top sections are pulled a short distance towards each other. When the extension leaf is turned in the longitudinal direction of the table the table top sec¬ tions are pulled completely together. In the last move¬ ment the extension leaf is wedged up against the under side of table top.

The mechanical construction 8, whereon the main parts of the table are assembled, and which procure the movements of the leaves 2a, 2b, 4 is created as a flat

rectangular construction about a welded mounting frame 12 of steel profiles and having side beams 14a, 14b of rectangular steel profiles and two end elements 16 of bent sheet material.

The two table top sections 2a, 2b are assembled on a sleigh each (see Figs. 8 and 10 ) consisting of two side aprons 18a, 18b in the shape of rectangular steel profiles, which are slidably guided on rollers 20a, 20b on the outer side of the side beams 14a, 14b of the mounting frame. At heavy loads as occurring with marble table tops a construction can be used instead where the side beams have an outwardly open C-shaped cross-section and where the side beams of the sledge has driving wheels, e.g. wheels of nylon, which can roll inside the C-section. Thereby bigger wheels can be used resulting in a lighter surface pressure. It appears, in fact, that by small wheels and heavy surface pressure the material of the profiles can be brought to the apparent limit of elasticity. Thereby wheel prints in the rails are caused, resulting in an inferior running, and at the same time there is a risk of abrasion of the track re¬ sulting from askew running in the rails. At the end of the sleigh the side beams are connected to a cross bar. At the two outermost corners of the sleigh there are at a distance in a plane above the frame with distance elements fixed mountings 22a, 22b in the shape of hori¬ zontal leaf pieces, whereon a table top section is placed and mounted by screws from the under side. The height of the distance elements are adjusted such that the extension leaf can be contained between the under side of the table top and the upper side of the mounting frame/side aprons. For adjusting the table top sections and the leaf the cross member 30 mentioned in the fol¬ lowing can be made of a U-profile with the opening up¬ wards and wherein is put a loose second U-profile with the back turning upwards. At each side of the first

U-profile is mounted an adjusting screw for raising or lowering the second U-profile and thereby the edge of the leaf or top sections. If the angularity is out of line it can be realigned by adjustment at one of the sides.

The synchronous movement of the two table top sec¬ tions (see Figs. 8 and 9) is generated by an almost circular cam disc 24 and two three-link rod connections 26, each of which is linked to the two table top sec¬ tions 2a, 2b and to the cam disc, which is rotatably embedded about a vertical axis in a bridge 28 in the shape of a piece of flat steel mounted transversely at the centre of the mounting frame. The three-linked rod connection comprises three pieces of flat steel linked together, where the first 26a by its free end is con¬ nected to the cam disc at its periphery. The other end of the rod is connected to the second rod 26b approxi¬ mately at the centre thereof. One end of this rod is connected to the mounting frame of a cross bar 30. The other end is connected to the end of the last link rod 26c, the other end of which is connected to a cross bar 32 at the sleigh. The first rod of the link connections has a bend, so they can be connected diametrically oppo¬ site on the cam disc and in order that they are clear of a central axis 34 to the extension leaf. In the starting position, where the two table top sections are drawn closely together, the connection point af the link con¬ nections to the cam disc is positioned opposite the corresponding table top section and at the longitudinal centre line of the table.

Rotation of the cam disc will cause the sleigh to displace in the longitudinal direction of the table through the interchange in the link connection. At the initial rotation of the cam disc a dislocation of the table top sections will not occur. This short standstill passes to a minimal dislocation of the sections and

further into an accelerated and subsequently lessening elapse, when the cam disc is turned 180° and the con¬ nection of the link connection to the cam disc is turned about at the opposite side in the longitudinal direction of the table. This corresponds to the table top sections being in their maximum extracted position cf. Fig. 6, that is to say where the distance between the table top sections 2a, 2b are larger than the width of the exten¬ sion leaf.

For stabilizing the edges of the leaves compared to each other the edges of the table top sections are pro¬ vided with outwardly projecting dowels 36, see Fig. 12, which are staggered to each other and intended for en¬ gagement with corresponding holes at the opposite edge. The extension leaf is provided with corresponding holes as in the edges of the two table top sections. The extra distance, which the two table top sections is retracted from each other in relation to the width of the exten¬ sion leaf, is in order to allow space for these outward- ly projecting dowels and such that they do not scratch against the edges.

When the cam disc is oversteered, that is to say is turned an additional short distance, the table top sec¬ tions are closed upon the extension leaf 4 and the dowels 36, which are bevelled, are caught in the cor¬ responding holes in the extension leaf. At storage of the extension leaf the cam disc is turned in the oppo¬ site direction, whereby the table top sections are pushed from each other, until the connection point of the link connection lies in the longitudinal centre line of the table in order that the dowels are clear of the extension leaf.

The construction of the cam disc (see Figs. 9 and 11) comprises two parallel disc elements 38a, 38b, which in the centre are assembled about a plastic hub 40 em¬ bedded about a hollow, vertical shaft bushing 42 welded

to the centre of the bridge 28 of the mounting frame, which consist of a rectangular steel profile. In order to make the cam disc run as easily as possible, the cam disc slides on a plastic washer 44 embedded about the shaft bushing. The extension leaf 4 is carried by a central stud 34 placed in the shaft bushing of the cam disc and at the top provided with a mounting 48, which is embedded in a groove at the under side of the exten¬ sion leaf and fixed by screws. Between and to the cross bar of the mounting frame and the bridge a rectangular steel profile 50 is mounted underneath in the longitu¬ dinal centre line of the table, wherein there is placed a longitudinal, upwards curved leaf 52 to almost balanc¬ ing the weight of the extension leaf, as the rotation axis of the extension leaf is supported on the peak of the spring leaf through a hole in the longitudinal pro¬ file. When the extension leaf is elevated and lowered, the stud slides freely in the bushing, but is, however, hindered from tearing up by a locking ring embedded in a groove in the lower end of the stud, which acts against the edge of the bushing.

Another and better construction for balancing the weight of the extension leaf proves to be a construction comprising a spring-loaded eccentric embedded at a cross axis in the profile 50, such that one end, the long end carries the stud and the other end connected to a hori¬ zontal helical spring, the other end of which is con¬ nected to an adjusting screw at the end of the profile 50. By tightening or loosening of the screw the spring- load can be adjusted to the weight of the actual exten¬ sion leaf. The construction offers the advantage of acting during the entire vertical movement of the leaf, in contrast to the spring leaf mainly acting in the lower position of the leaf.

The initial lowering of the extension leaf at ex¬ tension of the table top (mentioned in connection with

Fig. 2) and the terminating wedging against the under side of the table top when the leaf is brought in storage position is made by two wedge elements 54a, 54b of plastic (Figs. 11 and 9) . One wedge element 54 is mounted at the upper side of the cam disc, and the other element 54b at the leaf mounting. In the starting posi¬ tion the wedge 54b of the extension leaf rides on the wedge 54a of the cam disc such that the extension leaf is urged up to firm abutment against the under side of the table top. At the initial movement, that is to say rotation of the cam disc, its wedge element is turned away under the wedge element of the extension leaf, whereby the leaf is lowered a short distance, the equi¬ valent of the height of the wedge element, and it is clear of the table top. The wedge elements have a short length such that only by a short rotation of the cam disc they become clear of each other, and it occurs before movement of the two table top sections and swi¬ velling of the extension leaf, so the upper side of the leaf is not scratched. During the following movements the wedge elements get clear of each other. At termina¬ tion of the storage of the extension leaf the wedge of the cam disc is turned down under the wedge of the ex¬ tension leaf thereby elevating the leaf to firm abutment against the under side of the table top. It occurs upon completion of the other movements of the leaves. The two table top sections are only fixed at their outer ends, namely at the mountings of the sleighs, and stretch hanging freely towards each other. In the starting posi¬ tion the intersecting edges are however locked in rela¬ tion to each other by dowels as mentioned earlier but this is a loose fixation, which does not hinder movement of the two leaves in the vertical direction. Therefore the wedging of the extension leaf against the table top gives an essential contribution to stability of the table top sections, and at the same time hinders a

"flapping" movement of the extension leaf in the storage position which can be caused by the vibrations, which appear when using the table and floor tremors caused by traffic around the table.

For turning of the extension leaf this is at the under side provided with a driving pin 56 in the shape of an angled piece of steel rod, where one leg is em¬ bedded in a track at the under side of the leaf 4 and latched with a plate 58 screwed to the under side by screws, and where the other leg, which is the driving pin, projects through a hole in the leaf perpendicularly to the table top. At a level just above the cam disc there is a curve 60 in the shape of a plate welded to the mounting frame. The curve has a track, which runs along the periphery of the cam disc and stretches a quadrant from a starting position 62a for the driving pin of the extension leaf, where the leaf is turned in the longitudinal direction of the table, and a delivery position 62b, where the leaf is turned in a transverse direction of the table. At extension of the table the driving pin sits in the short track in the starting position 62a and stretches downwards along the periphery of the cam disc. During the initial rotation movement of the cam disc nothing occurs, until a notch 64 in the cam disc is opposite the driving pin, grips this and leads it along the curve, whereby the extension leaf swivels until the pin is caught in the delivery track 62b, cor¬ responding to the extension leaf being turned in a transversely position of the table. Due to tolerances of the construction and the inertia of the leaf in the swivelling movement the leaf has a tendency to turn too far, especially where very heavy extension leaves such as marble are concerned. To prevent this overswiveiling the leaf at its under side is provided with a depending stop which acts against the side beams. Further rotation of the cam disc can occur unimpeded, as the driving pin

is led outside the circumference of the cam disc. When the extension leaf shall be returned to the storage position the driving pin is again caught in the notch of the cam disc and is returned for delivery in the start¬ ing position. The length of the driving pin is adapted, such that it does not slide up its track, when the ex¬ tension leaf is elevated at level with the table top.

For elevating the extension leaf 4 (see Figs. 12,13,8 ) at level with the table top, when the exten¬ sion leaf is turned transversely to the table, at the inner side of the side beams 14a, 14b of the mounting frame there is a rod parallelogram, which is activated by the cam disc by a triangular pivot arm 66. The rod parallelograms are identical at each side and include four knee-joints 68a, 68b, each consisting of two small sheet materials, which by one end are hinged together. The other end, the lowermost, is pivoted to the mounting frame. The other end of the topmost sheet is pivoted to a horizontal longitudinal rod 70 parallel to the side beam and having a length at least approximately cor¬ responding to .the width of the extension leaf, and whereon the leaf is elevated and supported. The folding points of the knee-joints are interconnected by a through rod 72, which by a pull rod 74 in the shape of a piece of round bar steel is connected to the pivot arm, as the end of the pull rod is angled and catch into the connection rod, likewise the other end of the pull rod is angled and catch into a hole in an upstanding flange 76 of the pivot arm. As mentioned the pivot arm consists of an approximately isosceles triangular sheet material, which is pivotally mounted at a trestle 78 of bent steel plate, which in turn is welded to the upper side of the longitudinal profile 50, which contains the leaf spring. Thus the pivot arm can pivot about a point in the longi¬ tudinal centre line of the table. The top of the pulling arm, which stretches down under the cam disc, is stag-

gered in a plane closely against the under side of the disc and is provided with a longitudinal mesh notch 80 (see Fig. 8) . At the under side of the cam disc there is a driver 82 in the shape of the end of a through pin in the disc, and which is hindered from being pulled up by a locking ring at the under side of the disc. The driver is placed so far along the cam disc that it intermeshes with the notch in the pull arm 66 and is placed such in relation to the notch of the cam disc, which intermeshes with the pin 56 of the leaf 4 for swivelling of the leaf, that it is turned in position before the driving pin activates the pull arm 66 to swivel. Thereby there will occur a draw in the pull arm and the rod which interconnects the knee-joints. At the dislocation of the pull arm the knee-joints will rise, abut the under side of the extension leaf, which thereby is levelled at level with the table top. The knee-joints 68a, 68b are brought exactly over the folding point, such that they stand in locked position and form a firm support for the extension leaf. For bringing the knee-joints over the folding point, when the extension leaf shall be returned to the storage position, there is an activating rod 82 connecting the rod 70, which carries the extension leaf, with the interconnecting rod 72 of the knee-joints. In the levelling position the rod 82 has an inclined posi¬ tion opposite the position of the knee-joints, in order that the weight of the extension leaf will push the rod opposite the angle of the knee-joints and thereby pull these over the angle or the changing position. The ex¬ tension leaf will by its own weight, controlled by the intermeshing between the pullarm and the cam disc, be lowered to its lowermost position, whereafter the swi¬ velling is initiated. At swivelling to the storage posi¬ tion and to the levelling position the extension leaf is supported by ball wheels mounted at the upper side of the side beams 14a, 14b. This relieves the stud 34 and

consequently the positioning requirements are less stringent. For the sake of good order it should be no¬ ticed that the knee-joints and the pull arms at each side are opposite each other, as the pull is reciprocal at the swivelling of the pull arm 66.

The rotation of the cam disc is provided by a cable (see Figs. 9,11), where the cable 84 is put about the cam disc in a track 86 on the periphery between the topmost and lowermost plate of the disc, as the edge 88, about which these are mounted, is retracted to the peri¬ phery. For tightening of the cable the edge element 88 is disconnected and the ends rounded off towards the centre topmost plate, wherein there is a slot 90 with a spring 92, one end of which is fixed to the cam disc by a pin 82, and where the cable is put around the other end of the spring. The cable is by one end fixed to the end of a pull rod 96, which at the opposite end carries an operating lever 10, which is outside the mounting frame. The other end of the cable is fixed to the rod against the lever. The mounting is made in a simple manner by putting the ends of the cable in two tracks closely together in the rod and binding a knot at the ends of the cable, which is contained in a slot or at the end in an oblique cut off of the rod. The rod ex¬ tends in the entire length of the mounting frame and engage the track at the edge of the cam disc. The rod is laid in a conducting tube 100, which by mountings is mounted to the mounting frame, and is disconnected at the cam disc for free movement of the cable.

By a pull of the lever, which merely is a piece of round bar steel welded to the end of the pull rod, the cam disc is brought to swivel as a consequence of the cable being put around the disc, which will release the earlier described movements in the consistent order, until the table is extended by the extension leaf. The travelling of the lever is relatively long corresponding

to it being placed exactly below the end of the table top concurrently with the two table top sections being moved away form each other. This is psychologically right for the user, that a pull at the operating lever calls forth a comparable travelling of the table top sections. The storage of the extension leaf happens merely by pushing the lever. The extension leaf can be locked in the extreme positions by a breaking device which in a simple manner consists of a pull rod having a rectangular cross section and the steady tube a square cross section such that the lever can be turned causing the sides of the rod to contact with forwardly directed tongues in the steady tube and by a key locking locks the operating rod.

In the embodiment described the cam disc is brought to rotation by a cable, however, a rack meshing gears at the periphery of the cam disc could also be used. The rack could be placed at one of the table top sections, such that this is utilized as an operating lever. The rotation could also be undertaken by an electric gear motor. The parallelograms at the sides for levelling and lowering of the extension leaf could be replaced by eccentric suspended elements. Thus a variety of dif¬ ferent constructive solutions of details do not fall outside the scope of the invention.