Patent Description:
Lifting columns comprising a telescopic guide and a box-shaped housing for height-adjustable tables were developed in the late <NUM>, 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> of <CIT>. A different type of lifting column is described in <CIT>, where the entire drive unit, i.e. electric motor, transmission and various electronics, is integrated in the telescopic guide.

A supporting frame comprising an upper frame, which typically comprises two longitudinal members and two cross members, at least one lifting column and at least one foot. The lifting column can, as described above, be constructed with or without a box-shaped housing at the upper end. The longitudinal members are usually constructed as throughgoing tubular profiles placed in parallel having a mutual distance between them 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 are usually welded up or should 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 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. Examples of such a table is shown in <CIT> and <CIT>. The assembly of the supporting frame is relatively troublesome and time-consuming. This is owing to the fact that the parts of the supporting frame are relatively large and heavy. Further, the assembly of the supporting frame requires a number of screw operations, which require that each part is placed correctly relative to each other.

The purpose of the invention is to provide a supporting frame comprising electrically driven lifting columns for an adjustable piece of furniture, which in a simple and non-time-consuming manner can be assembled and secured to the desired piece of furniture.

This is achieved according to the invention by constructing the supporting frame with a base unit having a compartment at least for partial reception of the housing of the lifting column, and a cross member for mounting on the base unit. The supporting frame comprises a locking element, which when placed in a locked position exerts a squeezing force between the base unit, the housing of the lifting column and the cross member, by which the lifting column housing and the cross member are fixed in the base unit. The supporting frame further comprises means for retaining the locking element in the locked position. The lifting columns are of the type comprising telescopically arranged profiles with an upper and lower end, to which upper end a housing is secured. The base unit has a U-shaped cross section with two parallel side walls having a mutual distance between them corresponding to the width of the lifting column housing and where the guide for the base unit is placed on the parallel side walls. Hereby, a supporting frame is achieved, which is simple and easy to assemble and mount without the use of tools. Thus, the before mentioned screw operations are eliminated. By having minimum clearance between the side walls of the base unit and the lifting column housing, an improved fixation of the housing to the base unit is achieved.

In an embodiment the cross member has a profile with a C-shaped cross section prepared for engagement with the base unit. In a further embodiment the base unit comprises flaps for engagement with the cross member. Thus, the base unit can be received in the cross member.

In an embodiment the base unit comprises a guide, which depending on the construction of the supporting frame functions as a guide for correct mounting of the lifting column, including fixation of this in the base unit.

In an embodiment of the supporting frame the guide of the base unit is placed on or constructed in the side walls of the base unit.

In an embodiment the base unit comprises a transverse wall, which connects the two parallel side walls of the base unit, against said transverse wall a rear end of the lifting column housing can rest. The fixation is improved in that yet another surface of the housing is fixed to the base unit.

In an embodiment the transverse wall comprises a tongue, which with an end protrudes into the compartment of the base unit, i.e. the compartment which at least partially receives the housing of the lifting column. In another embodiment the cross member comprises a tongue which, when the cross member is mounted to the base unit, with an end protrudes into the compartment of the base unit, i.e. the compartment which at least partially receives the housing of the lifting column.

In an embodiment the lifting column housing comprises an indentation for engagement with the tongue in the transverse wall or the cross member. By this engagement the fixation between the housing of the lifting column and the base unit is improved in that the lifting column housing is pushed towards the bottom of the base unit when the locking element is brought into its locked position.

In an embodiment the base unit comprises a flap placed such that it is in continuation of the side walls of the base unit. Thus, a direct or indirect interface between the housing of the lifting column and the cross member is ensured. When the locking element is brought into its locked position, a squeezing force between the base unit, the lifting column housing and the cross member can be achieved.

In an embodiment the supporting frame comprises a clamp with guides for cooperation with the guide on the base unit. In this embodiment the housing of the lifting column is placed between the base unit and the clamp. When the locking element is placed in the locked position, this will in cooperation with the base unit and the clamp exert a squeezing force on the lifting column housing, which propagates to the cross member. Thus the housing of the lifting column and the cross member is fixed to the base unit. The locking element can in an embodiment be inserted and retained in the locked position in an opening in the clamp.

In an embodiment the cross section of the base unit is in the shape of a hollow profile in which the lifting column housing can be arranged by sliding it in from an open end. Expediently, the hollow profile of the base unit comprises a recess for the telescopically arranged profiles of the lifting column, by which the entire housing of the lifting column can be received in the base unit. For fixation of the lifting column in the base unit the hollow profile of the base unit can comprise an opening in which the locking element is inserted and retained in a locked position.

In an embodiment the housing of the lifting column comprises a guide for cooperation with the guide on the base unit. Thus, the lifting column and the cross member can be fixed to the base unit without using a clamp. For fixation of the lifting column the base unit comprises an opening in which the locking element can be inserted and retained in the locked position.

In an embodiment of the supporting frame the lifting column is of the type, where an electric motor and a transmission for bringing about the movement of the lifting column are arranged in the housing of the lifting column.

In another embodiment the supporting frame is of the type where an electric motor and a transmission for bringing about the movement of the lifting column are arranged in one of the telescopically arranged profiles and where the housing as a separate unit is mounted on a free end of one of the outermost telescopically arranged profiles. The housing thus functions as an adaptor by which it is possible to use this type of lifting column for the supporting frame.

The invention will be explained more fully below under reference to the accompanying drawings. For the sake of the clarity of the drawings it should be noted that the shown elements often are depicted as cut off. A dotted line through the element concerned shows where it has been shortened. In the drawings:.

The height-adjustable table <NUM> shown in <FIG> comprises a table top <NUM> having a front side <NUM> at which a user is expected to be situated, a rear side <NUM>, a right side <NUM> and a left side <NUM>. At the right side <NUM> and left side <NUM>, respectively, of the table top <NUM> there is a telescopic lifting column <NUM>. The lower end of the lifting columns <NUM> is mounted with an elongated foot <NUM>, which extends in a direction across the table. The telescopic lifting columns <NUM> can be adjusted in their longitudinal direction by means of an operating unit <NUM>, by which the height of the table top <NUM> can be adjusted. The two lifting columns <NUM> are connected to a control box comprising a controller. Further, the control box is connected to the operating unit <NUM> from which the height of the table top <NUM> can be adjusted.

<FIG> shows a first embodiment of a supporting frame for the height-adjustable table shown in <FIG>. The supporting frame further comprises two base units <NUM>,<NUM> and two clamps <NUM>,<NUM> between which the lifting columns are mounted. The two base units <NUM>,<NUM> are connected to the two telescopically arranged longitudinal members <NUM>,<NUM>. Further, each of the base units has a cross member <NUM>,<NUM> secured thereto.

<FIG> illustrate a lifting column <NUM> shown in a perspective view and from the side, respectively. <FIG> shows the same lifting column <NUM> in a partially extended position. The lifting column comprises a guide consisting of three telescopically arranged rectangular profiles <NUM>,<NUM>,<NUM>. Further, the lifting column <NUM> comprises a box-shaped housing <NUM>. For bringing about the movement of the lifting column <NUM> this comprises a linear actuator, see <FIG>. The linear actuator consists of a motor unit <NUM> arranged in the box-shaped housing <NUM> (see <FIG>) and a linear moveable activation element arranged in the hollow of the rectangular profiles <NUM>,<NUM>,<NUM>. The motor unit <NUM> comprises a reversible electric motor <NUM> and a transmission <NUM>. The linear moveable activation element is constructed as a spindle unit connected to the transmission <NUM> of the motor unit through a hole in the bottom portion <NUM> of the motor housing. The spindle unit consists of a solid spindle <NUM>, a hollow spindle <NUM> and a tube <NUM> with a spindle nut at the top. The housing <NUM> consists of a rectangular steel box having two parallel side portions <NUM>,<NUM>, a front end <NUM> and a rear end <NUM>, which are parallel, as well as a bottom portion <NUM>. The top of the housing <NUM> can be closed by means of a cover <NUM>. The external surfaces on the front end <NUM> and the two side portions <NUM>,<NUM> comprise two surfaces. A first plane surface 31a,33a (see <FIG>), which extends from the top of the housing towards the bottom portion <NUM> of the motor housing and which is parallel to the longitudinal axis of the rectangular profiles <NUM>,<NUM>,<NUM>, and in continuation thereof a second plane surface 31b,33b, which describes an acute angle with the longitudinal axis of the rectangular profiles <NUM>,<NUM>,<NUM> and forms a connection with the bottom portion <NUM> of the motor housing. Consequently, the area of the top of the motor housing is larger than the area of the bottom portion <NUM>. The transition from the first plane surface to the second plane surface and further from the second plane surface to the bottom portion <NUM> is rounded off. The rear end further comprises two indentations 24a,24b;58a,58b.

<FIG> shows a perspective view of a different type of lifting column <NUM> without housing, a so-called in-line lifting column, where the entire drive unit, including electric motor <NUM> and transmission <NUM>, is arranged in the telescopically arranged profiles <NUM>,<NUM>,<NUM>. <FIG> shows a housing <NUM> as a separate unit intended for mounting at the topmost end of the lifting column <NUM>, more precisely for mounting in the profile <NUM>. The housing <NUM> consists of a rectangular steel box with two parallel side portions <NUM>,<NUM>, a front end <NUM> and a rear end <NUM>, which are parallel, as well as a bottom portion <NUM>. The top of the housing <NUM> can be closed by means of a cover. Further, the housing comprises a mounting surface <NUM> for mounting of a lifting column <NUM> of the type shown in <FIG>. The rear end further comprises two indentations 58a,58b. <FIG> shows a perspective view of the lifting column <NUM> mounted with the housing <NUM>.

The drive unit in <FIG> is constructed as a linear actuator for bringing about the telescopic movement of the lifting column <NUM>. The linear actuator comprises a spindle unit consisting of a solid spindle <NUM> and a hollow spindle <NUM>, both with external threads. At the lower end of the hollow spindle a spindle nut <NUM> for the solid spindle <NUM> is secured, said spindle nut <NUM> is constructed as a bushing with internal threads. By rotating the hollow spindle <NUM> the spindle nut <NUM> will screw itself up along the solid spindle <NUM>, as this is secured against rotation at its free end <NUM>. The hollow spindle <NUM> is surrounded by a drive tube <NUM>, which on the internal side is equipped with a number of axially running grooves <NUM>. At the uppermost end of the hollow spindle <NUM> the external side is fitted with a ring <NUM> having a number of external fins protruding into the grooves <NUM> on the drive tube <NUM>. Surrounding the drive tube <NUM> there is a guide tube <NUM> at the lower end of which, a spindle nut <NUM> for the hollow spindle <NUM> is secured. The spindle nut <NUM> is in the shape of a bushing with internal threads. When the drive tube <NUM> is rotated, the guide tube <NUM> will screw itself up along the hollow spindle <NUM>, as the guide tube <NUM> at its upper end is secured against rotation. As the hollow spindle <NUM> is driven around this will screw itself synchronously up along the solid spindle <NUM> as explained above, i.e. the axial movement is the joint movement of both hollow and solid spindle. The drive tube <NUM> is driven by an electric motor <NUM> through a transmission <NUM>. The transmission comprises a worm gear, which through a gear wheel set drives a crown wheel, which then drives the drive tube <NUM>.

<FIG> shows in a second embodiment of the supporting frame, a perspective view of a base unit <NUM> with two side walls <NUM>,<NUM>, a transverse wall <NUM> between the two side walls <NUM>,<NUM> and a bottom <NUM>. The side walls <NUM>,<NUM> are at the transverse wall <NUM> extended by two flaps <NUM>,<NUM> with two recesses located opposite each other, such that the flaps appear as double-sided hooks or clasps. Each side wall <NUM>,<NUM> comprises two guides <NUM>,<NUM>;<NUM>,<NUM> functioning as guiding. The transverse wall <NUM> of the base unit has two tongues <NUM>,<NUM>, which with their free ends face into and extend towards the bottom <NUM> of the base unit. <FIG> shows the base <NUM> in a longitudinal section parallel to the side walls <NUM>,<NUM>.

Under reference to <FIG> the first embodiment of the supporting frame is described in the following, including how to assemble it. Thus, the arrows <NUM>,<NUM> in <FIG> and <FIG>, respectively, show how the flaps <NUM>,<NUM> of the base unit are guided into the C-shaped profile of the cross member <NUM>. <FIG> shows, seen from the side wall <NUM> of the base unit <NUM>, how the flap <NUM> is received in the profile of the cross member <NUM>. <FIG> shows a perspective view of the placement of the base unit <NUM> in the cross member <NUM>. It is noted that both the base unit <NUM> as well as the cross member <NUM> comprises a number of mounting holes <NUM>,<NUM>;<NUM>,<NUM> for mounting of a table top to the supporting frame.

<FIG> show a perspective view and section of how the lifting column <NUM>, and more specifically, how the lifting column housing <NUM>, is placed in the base unit <NUM>. Due to the clarity of the figures the telescopically arranged profiles <NUM> have been shown cut off. The placement of the lifting column housing <NUM> in the base unit <NUM> is indicated by the arrows <NUM>,<NUM>, which thus show that the lifting column housing <NUM> is arranged against the bottom <NUM> of the base unit and between the side walls <NUM>,<NUM> of the base unit. The lifting column <NUM> is positioned such that the rear end <NUM> (corresponding to the rear end <NUM>,<NUM> in <FIG> and <FIG>, respectively) of the lifting column housing <NUM> engages the transverse wall <NUM>. The rear end <NUM> has two indentations <NUM> (only one has been numbered) corresponding to the indentations 24a,24b;58a,58b in <FIG> and <FIG>, respectively. As it appears from <FIG> the tongue <NUM> in the transverse wall <NUM> of the base unit is in engagement with the indentation <NUM> on the lifting column housing <NUM>.

<FIG> and <FIG> show how the clamp <NUM> is mounted on the base unit <NUM>. The clamp <NUM>, which has a U-shaped cross section, is furnished with two holes <NUM>,<NUM>;<NUM>,<NUM> on each side wall <NUM>,<NUM>. When the clamp <NUM> is mounted on the base unit, the holes <NUM>,<NUM>;<NUM>,<NUM> of the clamp are in engagement with the guide <NUM>,<NUM>;<NUM>,<NUM> of the base unit, by which the clamp <NUM> can be guided along the base unit <NUM>. The clamp <NUM> has an opening <NUM> in which a locking element in the shape of a locking block <NUM> can be inserted, see <FIG>. The locking block <NUM> can in a rotatable manner be pressed into the opening to a locked position, see <FIG>. As shown in <FIG> the surface <NUM> of the locking block will during this movement engage the front end <NUM> of the lifting column housing <NUM>. Through the engagement mentioned above between the holes <NUM>,<NUM>;<NUM>,<NUM> of the clamp and the guides <NUM>,<NUM>;<NUM>,<NUM> of the base unit, as well as the engagement of the locking block <NUM> with the front end <NUM> of the lifting column housing <NUM>, a displacement between the lifting column housing <NUM> and the clamp <NUM> relative to the base unit <NUM> occurs. As indicated by the arrows <NUM>,<NUM>,<NUM> in <FIG> the clamp <NUM> is pushed in a direction away from the transverse wall <NUM> of the base unit and towards the bottom <NUM> of the base unit. Further, the lifting column housing <NUM> is pushed against the transverse wall <NUM> of the base unit. Through the engagement between the tongue <NUM> in the transverse wall <NUM> of the base unit and the indentation <NUM> in the rear end of the housing, the tongue <NUM> exerts a downwardly directed force against the bottom of the indentation <NUM>. When the tongue <NUM> is pushed backwards toward the transverse wall <NUM> it rotates about its point of attachment and thereby extends further downwards. Thus, the lifting column housing <NUM> is pushed further down towards the bottom <NUM> of the base unit, see arrow <NUM> in <FIG>. With a point of rotation located in the transition from the bottom <NUM> of the base unit to the transverse wall <NUM> of the base unit, the transverse wall is pushed against the cross member <NUM>, see arrow <NUM> in <FIG>. Thus, the lifting column <NUM> and the transverse wall <NUM> are positioned and fixed to the base unit. <FIG> shows how the supporting frame according to the first embodiment appears assembled.

<FIG> shows an exploded perspective view of an embodiment of the supporting frame not according to the invention. Here, the base unit <NUM> is designed with a cross section as a rectangular hollow profile. The base unit <NUM> comprises an opening <NUM> adapted for the locking element <NUM>. The base unit <NUM> further comprises a recess <NUM>, which is open towards one end of the base unit <NUM>. In continuation of the same end of the base unit <NUM> the side walls <NUM>,<NUM> have a number of hook- or clasp-shaped flaps <NUM>,<NUM> which are prepared for engagement with a corresponding number of holes <NUM>,<NUM> in a cross member <NUM>. For assembly of the supporting frame the housing <NUM> is placed on the lifting column <NUM> in the base part <NUM> in such a manner that the telescopically arranged profiles <NUM> of the lifting column extend from the recess <NUM> in the base unit <NUM>. Subsequently, the cross member <NUM> is secured to the base unit <NUM> through engagement between the flaps <NUM>,<NUM> and the recesses <NUM>,<NUM>. Finally, the locking element <NUM> is inserted into the opening <NUM> and pressed into a locked position. Thus, the lifting column housing <NUM> is pushed against the cross member <NUM>. Through an engagement between the tongues <NUM>,<NUM> on the cross member <NUM> and indentations on the rear end of the lifting column housing <NUM> (corresponding to the indentations 24a,24b;58a,58b on <FIG> and <FIG>, respectively), the lifting column housing <NUM> is pushed down towards the bottom of the hollow profile of the base unit. Thus, the lifting column <NUM> and the cross member <NUM> are fixed to the base unit <NUM> and the supporting frame appears assembled.

<FIG> shows a third embodiment of the supporting frame in exploded perspective view and seen from the end of the telescopically arranged profiles of the lifting column and towards the lifting column housing, respectively. The base unit <NUM> has a U-shaped cross section and the side walls <NUM>,<NUM> each comprises two guides <NUM>,<NUM>;<NUM>,<NUM>. On the lifting column <NUM> the side walls <NUM>,<NUM> of the housing <NUM> likewise comprises guides <NUM>,<NUM>. It is noted that only the guides <NUM>,<NUM> on the side wall <NUM> are shown. Corresponding guides are located at the opposite side wall <NUM>. The guides <NUM>,<NUM> on the side wall <NUM> are intended for engagement with the guides <NUM>,<NUM> on the side wall <NUM> of the base unit <NUM>. Each of the side walls <NUM>,<NUM> comprises an opening <NUM>,<NUM> in which a locking element in the shape of a locking block <NUM>,<NUM> can be inserted and fastened.

In continuation of the side walls <NUM>,<NUM> opposite of the holes <NUM>,<NUM> the base unit <NUM> comprises hook- or clasp-shaped flaps <NUM>,<NUM> prepared for engagement with the holes <NUM>,<NUM> on the cross member <NUM> which thus can be mounted to the base unit <NUM>. When the housing <NUM> of the lifting column subsequently is placed in the base unit <NUM> the guides <NUM>,<NUM> on the side wall <NUM> enters into engagement with the cooperating guides <NUM>,<NUM> on the side wall <NUM> of the base unit <NUM>. The locking blocks <NUM>, <NUM> are subsequently inserted into openings <NUM>,<NUM>, and can in a rotatable manner be pressed down into the openings <NUM>,<NUM> to a locked position. Thus, the lifting column housing <NUM> is pushed against the cross member <NUM>. Through an engagement between the tongues <NUM>,<NUM> in the cross member <NUM> and the indentations in the rear end of the lifting column housing <NUM> (corresponding to the indentations 24a,24b;58a,58b), the lifting column housing <NUM> is pushed down towards the bottom <NUM> of the base unit. A similar principle is shown in <FIG>. Thus, the lifting column <NUM> and the cross member <NUM> are fixed to the base unit <NUM> and the supporting frame thus appears assembled.

<FIG> show alternative embodiments of a clamp <NUM> and a base unit <NUM>, respectively. In order to increase the mechanical strength the clamp <NUM> is constructed with two reinforcements <NUM> on the outer side of the bottom <NUM> of the U-shaped profile of the clamp <NUM>. For the same purpose the base unit <NUM> is constructed with reinforcements <NUM>, <NUM> on each of the side walls <NUM>,<NUM> of the base unit <NUM>.

The construction and functions of the locking block, as described above, are described in the following with reference to <FIG>, where the locking block is referenced <NUM>. The locking block <NUM> is in all essentials wedge-shaped with two sides <NUM>,<NUM>, a top surface <NUM>, a first end surface, a rear surface <NUM> and a second end surface, front surface <NUM>.

The top surface <NUM> comprises a recess <NUM>,<NUM> at each of the two sides <NUM>,<NUM>. At the transition from the top surface <NUM> to the rear surface <NUM> the locking block comprises a projecting edge <NUM>. The projecting edge <NUM> comprises a vertical surface <NUM> for engagement with a side surface in the opening in which the locking block is to be fixed. The projecting edge <NUM> further comprises a horizontal surface <NUM> for engagement against the underside of the unit (clamp or base unit) in which the locking block <NUM> is fixed. The top surface <NUM> extends with a collar <NUM> over the two sides <NUM>,<NUM> and the front surface <NUM>. The underside <NUM> of the collar <NUM> is intended for engagement against the upper side of the unit (clamp or base unit) in which the locking block is fixed.

The transition from the underside <NUM> of the collar <NUM> to the two sides <NUM>,<NUM> of the locking block and the front surface <NUM> is approximately perpendicular to the top surface <NUM>. After the transition the front surface <NUM> has a concave course, after which it runs convex in the transition to the rear surface <NUM>. From this transition the rear surface <NUM> has a straight course, which finally is rounded off in the transition to the projecting edge <NUM>.

Each of the two recesses <NUM>,<NUM> in the sides <NUM>,<NUM> is furnished with a snap lock, constructed as flaps <NUM>,<NUM> which in a resting position extend in a direction perpendicular to the top surface <NUM>. The flaps <NUM>,<NUM> are secured to the bottom of the recesses <NUM>,<NUM>, which partially enclose the flaps <NUM>,<NUM>. The free space between the recesses <NUM>,<NUM> and the flaps <NUM>,<NUM> enables the flaps <NUM>,<NUM> to tilt in a direction perpendicular to the two sides <NUM>,<NUM> of the locking block.

Each of the flaps <NUM>,<NUM> of the snap lock comprises a collar with a projecting edge <NUM>,<NUM>, which has a surface parallel to the top surface <NUM>, prepared for engagement against the underside of the unit (clamp or base unit) in which the locking block is fixed.

For bringing the locking block <NUM> into a locked position the locking block <NUM> is inserted into an opening in a clamp or a base unit such that the projecting edge <NUM> is in engagement with a rear edge in the opening. Further, the concave transition from the front surface <NUM> to the rear surface <NUM> of the locking block <NUM> rests on the front end of the lifting column housing. By applying a force on the top surface <NUM> the locking block <NUM> is in a rotatable manner pressed into the opening; it rotates around the rear edge in the opening. Further, the lifting column housing is pushed in a direction away from the locking block <NUM>, as the contact between the front surface <NUM> of the locking block and the front end of the lifting column housing gradually changes from a line of action to a plane of action.

As the underside of the collar <NUM> abuts the upper side of the unit (clamp or base unit) in which the locking block is fixed, the flaps <NUM>,<NUM> of the snap locks are tilted backwards in a direction towards each other and returns to their resting position when the projecting edges <NUM>,<NUM> engages the underside of the unit (clamp or base unit) in which the locking block is fixed. The locking block <NUM> is thus wedged in the unit as a result of: the engagement between the horizontal surface <NUM> of the projecting edge <NUM> and the underside of the unit, the engagement in the plane of action between the front surface <NUM> of the locking block and the front end of the lifting column housing, and the engagement between the projecting edges <NUM>,<NUM> and the underside of the unit. Thus, the locking block <NUM> is in its locked position.

The locking block <NUM> can be brought out of its locked position by tilting the flaps <NUM>,<NUM> of the snap lock backwards in a direction against each other and bring the front surface <NUM> of the locking block out of engagement with the front end of the lifting column housing. The latter is expediently done by inserting a screw driver or the like into one of the holes <NUM>,<NUM> in the top surface <NUM>.

Claim 1:
Supporting frame comprising
a lifting column (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) with telescopically arranged profiles (<NUM>,<NUM>,<NUM>;<NUM>,<NUM>,<NUM>), where the telescopically arranged profiles (<NUM>,<NUM>,<NUM>;<NUM>,<NUM>,<NUM>) have an upper and lower end, to which upper end a housing (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) is secured,
a base unit (<NUM>,<NUM>,<NUM>,<NUM>) comprising a compartment at least for partial reception of the lifting column housing (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>),
a cross member (<NUM>,<NUM>,<NUM>,<NUM>) for mounting on the base unit (<NUM>,<NUM>,<NUM>,<NUM>),
a locking element (<NUM>,<NUM>,<NUM>,<NUM>), which when placed in a locked position exerts a squeezing force between the base unit (<NUM>,<NUM>,<NUM>,<NUM>), the lifting column housing (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) and the cross member (<NUM>,<NUM>,<NUM>,<NUM>), by which the lifting column housing (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) and the cross member (<NUM>,<NUM>,<NUM>,<NUM>) are fixed in the base unit (<NUM>,<NUM>,<NUM>,<NUM>), and where the locking element (<NUM>,<NUM>,<NUM>,<NUM>) comprises means for retaining the locking element (<NUM>,<NUM>,<NUM>,<NUM>) in the locked position
characterized in
that the base unit (<NUM>,<NUM>,<NUM>) has a U-shaped cross section with two parallel side walls (<NUM>,<NUM>;<NUM>,<NUM>) having a mutual distance between them which corresponds to the width of the lifting column housing (<NUM>,<NUM>).