Frame for a table

Abstract

A frame for sit-stand-tables comprising a longitudinal member (3), two height-adjustable legs (6, 7) with at least two telescopic profiles, namely an outer and an inner profile, and with a driving mechanism, driven by a motor unit (39), comprising an electric motor (46) and a gear. According to the invention the motor unit (39) is arranged in the longitudinal member (3) and connected to the driving mechanism in the height-adjustable legs (6, 7). Thus, a frame with a simplified construction is achieved. The construction of the legs (6, 7) can be simplified and at the same time the dimensions can be reduced, as it is not necessary to take the building-in of a motor into the legs into consideration. As both legs (6, 7) are driven by a joint motor unit (39), the electric control can also be simplified as it will not have to drive the two legs synchronously.

Claims

1. A frame for sit-stand-tables comprising a longitudinal member, two height-adjustable legs with at least two telescopic profiles, namely an outer and an inner profile, and with a driving mechanism, driven by a motor unit, comprising an electric motor and a gear, wherein the motor unit is arranged in the longitudinal member and connected to the driving mechanism in the height-adjustable legs, and wherein the longitudinal member is constituted by a middle section and two end sections, which are mounted longitudinal displaceable in the middle section.

2. The frame according to claim 1, further comprising a cross member that is secured to free ends of the two end sections of the longitudinal member, and a mounting bracket for mounting the leg to the longitudinal member is secured to the upper end of a profile.

3. The frame according to claim 2, wherein the mounting bracket is U-shaped and has an internal cross section corresponding to the outer cross section of the longitudinal member such that the longitudinal member can rest in this.

4. The frame according to claim 2, wherein for mounting an external side of the longitudinal member is equipped with a pair of axle journals for cooperating with a pair of recesses intended for that purpose located at an end of the mounting bracket of the leg facing towards the center of the longitudinal member.

5. The frame according to claim 4, wherein the external side of the longitudinal member is equipped with a pair of journals cooperating with a pair of tracks in the mounting bracket, said tracks extending from the upper edge of the mounting bracket.

6. The frame according to claim 2 further comprising a pawl unit arranged at the end of the longitudinal member, wherein side walls of the mounting bracket are constructed with two grooves intended for engagement with two pawls protruding from side walls of the longitudinal member.

7. The frame according to claim 6 wherein the pawl unit comprises a housing, the external shape of which corresponds to the internal shape of the cross member, wherein two pawls are embedded in the housing and protrude through a fissure in each side of the housing, and wherein the two pawls are spring-loaded by a coil spring mounted between the two pawls.

8. The frame according to claim 7, wherein the housing of the pawl unit, in addition to the two pawls, furthermore is secured by a cam on each side of the housing, said cams will when mounted rest in recesses in the side walls of the longitudinal member intended for that purpose.

9. The frame according to claim 2 wherein the cross member has a side wall, the height of which corresponds to the height of the longitudinal member, and at its top, the side wall extends into an outwardly extending flange, arranged on a level with the flanges of the longitudinal member.

10. The frame according to claim 9, wherein the cross member at its lower edge has a bracket containing a portion extending perpendicularly outwardly from the lower end of the cross member, said portion terminates into a perpendicular flange at its free edge.

11. The frame according to claim 10, wherein for each side of the bracket, a slit is arranged in the sidewall of the cross member.

12. The frame according to claim 11, wherein a cross slit is arranged at the bottom of the longitudinal member for receiving the perpendicular flange on the bracket of the cross member, and that the slits in the side wall of the cross member reaches over outwardly extending flanges in the side wall of the longitudinal member intended for the purpose.

13. The frame according to claim 1, wherein the middle section has a U-shaped cross section, where the side walls terminate in an outwardly extending flange which is folded to form a groove, and where the end sections also have a U-shaped cross section fitting into the middle section and where the side walls terminate in an outwardly extending flange fitting into the groove in the middle section.

14. The frame according to claim 1 wherein the motor unit is mounted in the longitudinal member and is in driving connection with the driving mechanisms of the height-adjustable legs.

15. The frame according to claim 14, wherein the motor unit comprises a housing with a cover.

16. The frame according to claim 15, wherein the housing is divided into two chambers, one for the motor unit and another for the electric control, which comprises a printed circuit board, among other things comprising a mains socket, which is accessible through a hole in the side of the longitudinal member, and separate from the mains socket there is at least one low voltage socket, which is accessible through a hole in the other side of the longitudinal member.

17. The frame according to claim 14, wherein the motor unit comprises an electric motor and a gear in the form of a worm gear having a worm in continuation of the motor shaft and in engagement with a worm wheel, and where the side of the worm wheel is furnished with one part of a spline connection for cooperating with the other part of the spline connection arranged on the driving mechanism of the legs.

18. The frame according to claim 14, wherein the motor unit is in connection with a drive shaft running through the longitudinal member to at least one of the legs.

19. The frame according to claim 18, further comprising a toothed wheel that is mounted on the end of the drive shaft, said toothed wheel is in engagement with the worm wheel of the motor unit, and that the opposite end of the drive shaft is in connection with a corresponding worm gear where the end of the drive shaft is in engagement with the worm which further is in engagement with the worm wheel which through a spline coupling is in engagement with the driving unit of the leg.

20. The frame according to claim 18, wherein the drive shaft is constructed telescopic such that this in a corresponding manner as the longitudinal member can be adapted to the current length of a given table.

21. The frame according to claim 20, wherein the drive shaft is constituted by three parts, where the two parts, which are in engagement with the motor unit and the gear, respectively, in the other side of the longitudinal member, are tubes, while the middle section is a solid rod, which with the ends is received in the two tubes, and that the cross section is polygonal, such that the rotation from the motor can be transferred to the drive unit for the leg at the other side of the longitudinal member.

22. A height-adjustable table comprising the frame according to claim 1.

23. A method for assembling a height-adjustable table wherein a frame for the table comprises a longitudinal member, two height-adjustable legs with at least two telescopic profiles, namely an outer and an inner profile, and with a driving mechanism, driven by a motor unit, comprising an electric motor and a gear, wherein the motor unit is arranged in the longitudinal member and connected to the driving mechanism in the height-adjustable legs and wherein the longitudinal member is constituted by a middle section and two end sections, which are mounted longitudinal displaceable in the middle section, where the longitudinal member is positioned on the underside of the table top and the length of this is adapted by displacing at least one of the end sections, preferably both end sections, relative to the middle section, after which the cross members are mounted to the outer ends of the respective end sections of the cross member, hereafter the legs are mounted by which the cross members are locked in their mounted position, hereafter the feet are mounted onto the lower end of the legs, they may, however, also be mounted to the legs before these are mounted to the longitudinal member, the cross members and the longitudinal member are secured to the underside of the table top.

Description

(1) The invention will be explained more fully below with reference to the embodiment shown in the accompanying drawing. In the drawing,

(2) FIG. 1 shows a perspective view of an assembled frame seen from above, but shown without feet,

(3) FIG. 2 shows an exploded view of one end of the frame shown in FIG. 1,

(4) FIG. 3 shows an exploded view of the end of the longitudinal member with the motor unit,

(5) FIG. 4 shows the end of the longitudinal member with mounted legs and shown without crossbar,

(6) FIG. 5 shows the pawl unit seen directly from the side and with the pawls shown in their fully extended position,

(7) FIG. 6 shows an exploded view of the pawl unit,

(8) FIG. 7 shows the pawl unit shown with one side wall removed,

(9) FIG. 8 shows a perspective view of the pawl unit where the pawls are shown retracted,

(10) FIG. 9 shows the longitudinal member mounted to the underside of a table top,

(11) FIG. 10 shows an exploded view of the end of one end of the frame,

(12) FIG. 11 shows the same as FIG. 5, but where the cross members are mounted to the ends of the longitudinal member,

(13) FIG. 12 shows a close-up illustration of the end of the longitudinal member shown with a leg ready for mounting to this,

(14) FIG. 13 shows the same as FIG. 11 but shown with the legs partially mounted,

(15) FIG. 14 shows a close-up illustration of the end of the leg in the same position as shown in FIG. 13,

(16) FIG. 15 shows the same as FIG. 14, but where the longitudinal member for the sake of clarity is shown without cross member,

(17) FIG. 16 shows the same as FIG. 13, but with the legs shown in the fully mounted position,

(18) FIG. 17 shows a close-up illustration of one end of the longitudinal member with cross member and the leg shown in its final mounted position,

(19) FIG. 18, shows the same as FIG. 16 but where the feet are indicated mounted on the lower end of the legs,

(20) FIG. 19 shows the frame in its maximum length, i.e. with the longitudinal member in its maximum extended position, and

(21) FIG. 20 shows the frame in its shortest length, i.e. with the longitudinal member in its fully retracted length.

(22) The height-adjustable table shown in FIG. 18 comprises a table top 1 and a frame 2 on which the table top is mounted. The frame comprises a length-adjustable longitudinal member 3, two cross members 4,5, one mounted to each end of the longitudinal member, a pair of height-adjustable legs 6,7, also called lifting columns, which with an upper end are mounted to the longitudinal member at either end thereof, and two feet 8,9, one mounted to a lower end of each height-adjustable leg.

(23) The longitudinal member 3 is constituted by a middle section 3a and two end sections 3b,3c, which are longitudinal displaceably mounted in the middle section 3a for adaption of the length of the longitudinal member to the actual length of the table top. The middle section 3a has a U-shaped cross section, where the side walls 10 terminate in an outwardly extending flange 11 which is folded to form a groove 12. The two displaceable end sections 3b,3c also have a U-shaped cross section fitting into the middle section 3a and where the side walls 13 terminate in an outwardly extending flange 14 fitting into the groove in the middle section, see FIGS. 2 and 4.

(24) To the free ends of the two end sections 3b,3c of the longitudinal member a cross member 4,5 is secured, said cross member 4,5 has a side wall 15, the height of which corresponds to the height of the longitudinal member 3. At the top, the side wall extends into a protruding flange 16, which is level with the flanges 14 of the longitudinal member 3. At the lower edge, the cross member has a bracket 17 with a perpendicular portion 17a protruding from the lower end of the cross member, which at its free edge is terminated in a perpendicular flange 17b. The side wall of the cross member has a slit 18,19 at either side of the bracket. The cross member 4,5 is mounted on the longitudinal member 3 by inserting the perpendicular flange 17b into a cross slit 20 intended for that purpose in the bottom of the longitudinal member 3, while the slits 18,19 in the side wall 15 of the cross member grip over protruding flanges 21,22 intended for that purpose in the side walls of the longitudinal member 3, see FIG. 10.

(25) At the free end of the longitudinal member 3 a pawl unit 23 is mounted which comprises a housing 24, the outer shape of which corresponds to the internal shape of the longitudinal member. Two pawls 25a,25b are embedded in the housing 24, said pawls 25a,25b protrude through a fissure 26a,26b in each side of the housing. The two pawls are spring-loaded by a coil spring 27, mounted between the two pawls. In the side walls of the longitudinal member there is a recess 28a,28b in each side for the two pawls. When the housing 24 with the two pawls is inserted into the longitudinal member 3, the two pawls will automatically, due to the pre-tensioning of the spring be pressed out through the two fissures in the side of the longitudinal member. The housing 24 is further retained by a cam 29a,29b on each side of the housing, said cams will, when mounted, rest in recesses 30a,30b in the side walls of the longitudinal member intended for that purpose, see FIGS. 5-8.

(26) The height-adjustable legs 6,7 comprise three telescopic profiles, namely an outer profile 6a, an intermediate profile 6b and an inner profile 6c, where the lower end of the outer profile has a bottom part with screw holes for mounting of a foot 8,9. A mounting bracket 31 for mounting of the leg to the longitudinal profile is secured to the upper end. The mounting bracket 31 has a U-shaped cross section and has an internal cross section corresponding to the outer cross section of the longitudinal member 3, such that this can rest therein. For mounting of the longitudinal member 3 this is on the outer side equipped with a pair of axle journals 32a,32b for cooperating with a pair of recesses 33a,33b intended for that purpose located at the end of the mounting bracket 31 of the leg facing towards the center of the longitudinal member 3. When the leg 6 is mounted, this is held in a horizontal position against the longitudinal member 3, see FIG. 12, such that its mounting bracket with the recesses 33a,33b is placed over the two axle journals 32a,32b on the outer side of the longitudinal member 3. For additional fixation of the leg 6, the external side of the longitudinal member is equipped with a pair of journals 34a,34b for cooperating with a pair of tracks 35a,35b in the mounting bracket 30, said tracks run from the upper edge of the mounting bracket. The axle journals 32a,32b and the cooperating recesses 33a,33b in the end of the mounting bracket 30 lock the leg against movement in the vertical direction, while the journals 34a,34b and the cooperating tracks 35a,35b from the upper edge of the mounting bracket retains this against movement in the axial direction of the longitudinal member 3. Finally, the mounting bracket is locked at the front end by means of the pawl unit 23 at the end of the longitudinal member as two slits 36a,36b, intended for engagement with the two pawls 25a,25b which protrude from the side walls in the longitudinal member, are constructed in the sidewalls of the mounting bracket 30. Moreover, the securing of the leg is as a rule stabilized in that the U-shaped bracket 30 with the side walls is fitted in a close-fitting manner over the side of the longitudinal member 3 and in addition, the upper edge of the U-shaped bracket 30 rests against the lower edge of the protruding flanges 14 on each side of the longitudinal member 3b.

(27) The legs 6,7, also called lifting columns, are equipped with a driving mechanism in the form of a spindle unit comprising a solid spindle and a hollow spindle as well as a drive tube. The spindle unit is with its one side secured to the outer tube and with the other end secured to the inner profile, while the intermediate profile is secured to the hollow spindle such that it is guided synchronously with the inner profile. To the upper end of the drive tube, a pin 37a of a spline coupling is secured. At the bottom of the longitudinal member a hole 38 is constructed, which the spline coupling pin protrudes through, see FIG. 12.

(28) In the longitudinal member 3, a motor unit 39 is mounted, which comprises a housing 40 with a cover 41, see FIG. 13. The housing is divided into two chambers 40a,40b, one for the motor unit 39 and another for the electrical control, which comprises a printed circuit board 42, among other things with a mains socket 43 which is accessible through a hole in the side of the longitudinal member 3. Separate from the mains socket are two low voltage sockets 44, which are accessible through a hole in the other side of the longitudinal member. The motor unit 39 comprises an electric motor 45 and a gear 46 in the form of a worm gear with a worm in extension of the motor shaft and in engagement with a worm wheel. On the side of the worm wheel, the other part of the spline coupling is constructed, i.e. a recess 37b for receiving the spline coupling pin 37a, see FIG. 12. Moreover, the motor unit is connected to a drive shaft 47 which runs through the longitudinal member 3 to the other leg 7, see FIG. 1. At the end of the drive shaft, a toothed wheel is mounted, which is in engagement with the worm wheel of the motor unit. At the opposite end, the drive shaft 47 is in engagement with a corresponding worm gear 48, where the end of the drive shaft is in engagement with the worm, which further is in engagement with the worm wheel, which through a spline coupling is in engagement with the drive unit of the legs 5. It is noted that the drive shaft 47 is telescopic, such that this in a corresponding manner as the longitudinal member 3 can be adapted to the present length of a given table.

(29) The drive shaft 47 consists of three parts, where the two parts 47b,47c, which are in engagement with the motor unit 39 and the gear 48 at the other end of the longitudinal member, respectively, are tubes, while the middle section 47a is a solid rod, which with the ends is received in the two tube portions 47b,47c. The cross section is multi-edged such that the rotation from the motor can be transferred to the drive unit for the leg at the other end of the longitudinal member.

(30) The drive mechanism for bringing about the telescopic movement of the legs comprises a spindle unit, consisting of a solid spindle and a hollow spindle both having external threads. At the lower end of the hollow spindle, a spindle nut for the solid spindle is secured, said spindle nut is constructed as a bushing with internal threads. By rotating the hollow spindle, the spindle nut will screw itself up solid spindle as this is retained against rotation at its free end. The hollow spindle is surrounded by a drive tube furnished with a number of axially running grooves on its inner side. At the upper end of the hollow spindle, a ring is secured to the external side thereof, said ring having a number of fins on its outer side, which protrude into the grooves of the drive tube. A support tube surrounds the drive tube and at the lower end of the support tube a spindle nut for the hollow spindle is secured. The spindle nut is in the shape of a bushing with internal threads. When the drive tube is rotated, the support tube will screw itself up the hollow spindle as the support tube at its upper end is secured against rotation. As the hollow spindle is driven around, this will screw itself synchronously up the solid spindle, as previously explained, i.e. the axial movement is the joint movement of both the hollow and solid spindle. The drive tube is driven by the motor unit via the spline coupling.

(31) It is understood that elements or principles from the embodiment can be combined with consideration for the specific usage of the frame. The invention is here in particular mentioned in connection with sit-stand desks, but it is understood that the invention can also be used in connection with other types of tables such as work tables, counters, kitchen tables etc. It is furthermore noted that even though the invention initially is intended for driving one motor unit, the invention can also be realized such that the legs can be manually adjusted e.g. driven by a crank handle.