The present invention relates to a height-adjustable supporting frame comprising an upper frame with a longitudinal member and a cross member, and a lifting column with telescopically arranged profiles and a foot, and where the longitudinal member of the upper frame is designed as a cable tray. Lifting columns comprising a telescopic guide and a box- shaped housing for height-adjustable tables were developed in the late 1990s, where the telescopic guide has the appearance of a table leg. The box-shaped housing, usually rectangular, contains an electric motor, transmission and various electronics. An example of such a lifting column is shown in Fig. 1 of WO 2004/100632 Al to LINAK A/S. A different type of lifting column is described in WO 03/003876 Al to LINAK A/S, where the entire drive unit, i.e. electric motor, transmission and various electronics, is integrated in the telescopic guide.

A height-adjustable supporting frame preferably for a table prepared for mounting of lifting columns with a box-shaped housing comprises an upper frame, which typically comprises two longitudinal members and two cross members. The supporting frame further comprises a set of feet. The longitudinal members are usually designed as through-going tubular profiles located parallel with a mutual distance corresponding to the width of the box-shaped housing. To each end of the longitudinal members a cross member is secured. The longitudinal members and the cross members will normally have to be assembled by means of screws. A lifting column is mounted at each end in that the box-shaped housing is positioned between the longitudinal members and with one end up against the respective cross member. The lifting column is secured by means of screws through the two longitudinal members and the cross member into the box- shaped housing. An example of such a table is shown in Fig. 1 of US 6,509,705 B2 to LINAK A/S. A particular challenge in relation to the assembly of a height-adjustable supporting frame for a table is the placement of cables on and in connection with the table in such .a manner that statutory requirements are being complied with and the work space of the user above and under the table is taken as much into account as possible and as a minimum meets the norm requirements. Usually, the cabling for the lifting columns, including the connection to the control box and operating unit, is placed as best as possible on the underside of the table top. Additional cables for e.g. computer, screen etc. will often hang loosely from the table top or be secured to the underside of the table top. Alternatively, separate cable trays or cable concealers are known, which are mounted to the underside of the table top. This solution increases the total cost of the table. Therefore, none of these solutions seem optimum in terms of meeting statutory requirements, considerations for the work space of the user or the visual appearance of the table .

The purpose of the invention is to provide an alternative height-adjustable supporting frame preferably for a table, which in a simple manner can be assembled and hide the cabling in and around the height-adjustable table.

This is achieved according to the invention by designing the height-ad ustable supporting frame with an upper frame comprising a longitudinal member and a cross member, at least one lifting column with telescopically arranged profiles and at least one foot. Where the lifting column with a first end is secured to the upper frame and with a second end is secured to the foot, and where the longitudinal member is designed as a cable tray. The longitudinal member thus forms a space, which can function as a cable tray, which from one side can be easily accessed and from the other side can hide the stored content.

In an embodiment the longitudinal member consists of at least two profiles, which are arranged mutually telescopic. The span of the supporting frame can thus be increased or reduced in the longitudinal direction of the longitudinal members, by which the supporting frame can be adapted to tables of various size. Further, the supporting frame can be packed and transported relatively compact.

In an embodiment the height-adjustable supporting frame comprises a base unit secured to the upper frame and to which the lifting column is fixed in the base unit. In an embodiment the longitudinal member has a C-shaped or G-shaped cross section. These cross sections are characteristic in that they are open, and can thus be easily accessed from one side while hiding the content of the longitudinal member from the other side.

In an embodiment the profile of the longitudinal member has a mounting surface for securing it to e.g. a table top.

In an embodiment the invention further relates to a height-adjustable table comprising a height-adjustable supporting frame of the type mentioned above.

The invention will be explained more fully below under reference to the accompanying drawings. In the drawings: Fig. 1 is a height-adjustable table equipped with lifting columns,

Fig. 2 is a supporting frame for the height- adjustable table shown in Fig. 1,

Fig. 3 is a perspective view of a lifting column,

Fig. 4 is a lifting column in a retracted position seen from one side,

Fig. 5 is a lifting column in a partially extended position seen from one side,

Fig. 6 is a section through the lifting column shown in Fig. 5,

Fig. 7 is a perspective view of a lifting column, where the drive unit is arranged in the telescopically arranged profiles, Fig. 8 is a housing as a separate unit for the lifting column in Fig. 7,

Fig. 9 is the lifting column in Fig. 7 mounted with the housing in Fig. 8,

Fig. 10 is a section through the lifting column shown in Fig. 7, Fig. 11 is a supporting frame in a second embodiment comprising telescopically arranged longitudinal members,

Figs. 12 and 13 are a perspective view of the two longitudinal members in Fig. 11 in a retracted and partially extended position, respectively.

Fig. 14 is the longitudinal members in Figs. 11 to 13 seen from their one end, and

Fig. 15 is a second embodiment of the telescopically arranged longitudinal members seen from their one end. The height-adjustable table 1 shown in Fig. 1 comprises a table top 2 having a front side 3 at which a user is expected to be situated, a rear side 4, a right side 5 and a left side 6. At the right side 5 and left side 6, respectively, of the table top 2 there is a telescopic lifting column 7. The lower end of the lifting columns 7 is mounted with an elongated foot 8, which extends across the table. The telescopic lifting columns 7 can be adjusted in their longitudinal direction by means of an operating unit 9, by which the height of the table top 2 can be adjusted. The two lifting columns 7 are connected to a control box comprising a controller. Further, the control box is connected to the operating unit 9 from which the height of the table top 2 can be adjusted. Fig. 2 shows a first embodiment of a supporting frame for the height-adjustable table shown in Fig. 1. The supporting frame comprises two base units 10,11 and two clamps 12,13 between which the lifting columns are mounted. The two base units 10,11 are connected to the two telescopically arranged longitudinal members 14,15. Further, each of the base units has a cross member 16,17 secured thereto.

Figs. 3 and 4 illustrate a lifting column 18 shown in a perspective view and from the side. Fig. 5 shows the same lifting column 18 in a partially extended position. The lifting column 18 comprises a guide consisting of three telescopically arranged rectangular profiles 19,20,21. Further, the lifting column 18 comprises a box-shaped housing 22. For bringing about the movement of the lifting column 18 this comprises a linear actuator, see Fig. 6. The linear actuator consists of a motor unit 23 arranged in the box-shaped housing 22 (see Fig. 6) and a linear moveable activation element arranged in the hollow of the rectangular profiles 19,20,21. The motor unit 23 comprises a reversible electric motor 25 and a transmission 26. The linear moveable activation element 24 is designed as a spindle unit which is connected to the transmission 26 of the motor unit through a hole in the bottom portion 27 of the motor housing. The spindle unit consists of a solid spindle 28, a hollow spindle 29 and a tube 30 with a spindle nut at the top. The housing 22 consists of a rectangular steel box having two parallel side portions 31,32, a front end 33 and a rear end 34, which are parallel, as well as a bottom portion 27. The top of the housing 22 can be closed by means of a cover 35. The external surfaces on the front end 33 and the two side portions 31,32 consist of two surfaces. A first plane surface 31a, 33a (see Fig, 4), which extends from the top of the housing towards the bottom portion 27 of the motor housing and which is parallel to the longitudinal axis of the rectangular profiles 19,20,21, and in continuation thereof a second plane surface 31b, 33b, which forms an acute angle with the longitudinal axis of the rectangular profiles 19,20,21 and connects with the bottom portion 27 of the motor housing. Consequently, the area of the top of the motor housing is larger than the area of the bottom portion 27. The transition from the first plane surface to the second plane surface and further from the second plane surface to the bottom portion 27 is rounded off. The rear end further comprises two indentations 24a, 24b.

Fig. 7 shows a perspective view of a different type of lifting column 35 without housing, a so-called in-line lifting column, where the entire drive unit, including electric motor 37 and transmission 38, is arranged in the telescopically arranged profiles 39,40,41. Fig. 8 shows a housing 42 as a separate unit intended for mounting at the topmost end of the lifting column 35, more precisely for mounting in the profile 41. The housing 42 consists of a rectangular steel box with two parallel side portions 43, 44, a front end 45 and a rear end 46, which are parallel, as well as a bottom portion 47. The top of the housing 42 can be closed by means of a cover. Further, the housing comprises a mounting surface 48 for mounting of a lifting column 35 of the type shown in Fig. 7. The rear end further comprises two indentations 58a, 58b. Fig 9 shows a perspective view of the lifting column 35 mounted with the housing 42. The drive unit in Fig. 10 is designed as a linear actuator for bringing about the telescopic movement of the lifting column 35. The linear actuator comprises a spindle unit consisting of a solid spindle 49 and a hollow spindle 50, both with external threads. At the lower end of the hollow spindle a spindle nut 51 for the solid spindle 49 is secured, said spindle nut 51 is designed as a bushing with internal threads. By rotating the hollow spindle 50 the spindle nut 51 will screw itself up along the solid spindle 49, as this is secured against rotation at its free end 52. The hollow spindle 50 is surrounded by a drive tube 53, which has a number of axially running grooves 54 on the internal side. At the uppermost end of the hollow spindle 50 the external side is fitted with a ring 55 having a number of external fins protruding into the grooves 54 on the drive tube 53. Surrounding the drive tube 53 there is a guide tube 56 at the lower end of which, a spindle nut 57 for the hollow spindle 50 is secured. The spindle nut 57 is a bushing with internal threads. When the drive tube 53 is rotated, the guide tube 56 will screw itself up along the hollow spindle 50, as the guide type 56 at its upper end is secured against rotation. As the hollow spindle 50 is rotated this will screw itself synchronously up along the solid spindle 49 as explained above, i.e. the axial movement is the joint movement of both the hollow and solid spindle. The drive tube 53 is driven by an electric motor 37 through a transmission 38. The transmission comprises a worm gear, which through a gear wheel set drives a crown wheel, which drives the drive tube 53.

Fig. 11 shows a second embodiment of a supporting frame for a height-adjustable table comprising two lifting columns 59,60 with telescopically arranged profiles. The lower end of the lifting columns 59,60 are mounted with an elongated foot 61,62. Each of the lifting columns 59,60 are fixed to a base unit 63,64 with a clamp 65, 66. Further, the cross members 67,68 are secured or fixed to the base units 63,64. In this embodiment the longitudinal member 69,70 consists of two profiles which are arranged mutual telescopically. The two base units 63,64 are connected to each of the two longitudinal members 69,70, which are telescopically arranged. More specifically, the longitudinal members 69,70 are designed as profiles in such a manner that the longitudinal member 69 can be guided into the longitudinal member 70. By means of this telescopic arrangement of the longitudinal members 69,70 the supporting frame can be adjusted in the length to a given length of a table top.

Figs. 12 and 12 show a perspective view of the two longitudinal members 69,70 in a retracted and partially extended position, respectively. Fig. 14 shows the longitudinal members 69,70 seen from their one end. Both longitudinal members 69,70 have an approximate C-shaped profile, where the longitudinal member 69 can be displaced into the longitudinal member 70. Each longitudinal member 69,70 further has a mounting flange 71,72 with a number of holes 73, 74 for mounting of the supporting frame to a table top.

Fig. 15 shows the two longitudinal members 75,76 seen from their one end. Both longitudinal members 75,76 have an approximate G-shaped profile, where the longitudinal member 55 can be displaced into the longitudinal member 76. Each longitudinal member 75,76 further has a mounting flange 77,78.

With their respective profiles the longitudinal members 12,-69, 70,-75, 76 form a space or an open groove in their entire length, which can function as a cable tray. In addition to cabling between the lifting columns, control box and operating unit, this space can be used for storage of e.g. socket-outlets, small power supplies etc. The half-open profile of the longitudinal members 12 ; 69, 70; 75, 76 makes the space easily accessible from one side and from the other side the content of the space is hidden. If the supporting frame is mounted to a table top 2 as shown in Fig. 1 the space in the longitudinal members 12 ; 69, 70; 75, 76 would normally be accessed from the front side 3 of the table top.