Lifting column

Abstract

The present invention relates to a lifting column (1) comprising a telescopic guide (2, 3, 4) and a drive unit (6) secured in a box- shaped housing (5) attached to the telescopic guide. The drive unit (6) comprises a bracket (14) on a second end of the electric motor (7), where the bracket (14) comprises at least two flanges (15, 16), each extending from the electric motor (7) towards opposing inner sides of the sidewalls of the box-shaped housing. The free end of each of the at least two flanges (15, 16) comprise a resilient pad (17, 18) abutting the inner side walls (5c, 5d) of the box-shaped housing.

Description

[0001] Lifting column

[0002] The present invention relates to a drive unit for a lifting column.

[0003] Lifting columns comprising a telescopic guide and a motor housing for height-adjustable tables where the telescopic guide appears as a table leg were developed in the late 1990s. The motor housing of the lifting column, which is usually rectangular, comprises a drive unit having an electric motor, gear and various electronics such as printed circuit board and wires. Common for such lifting columns is that the gear connects the output shaft of the electric motor with a spindle unit arranged inside the telescopic guide to extract or retract the lifting column upon activation of the electric motor.

[0004] An example of such a lifting column is disclosed in Fig. 1 of WO 2004 / 100632 A1 to LINAK A / S. Here, the electric motor is mounted in a tightly fitting recess in a block of foam plastics, which is then inserted into the motor housing of the lifting column. Apart from securing the electric motor inside the box-shaped housing, the block of foam also serves to dampen the noise and vibrations from the electric motor. The wires from the electric motor and the printed circuit board are guided along the block of foam plastics and out of the box-shaped housing.

[0005] Another way to mount the electric motor in the motor housing of the lifting column is disclosed in CN 103986268 to Zhejiang Jiecang Linear Motion Technology, where resilient blocks, which are slid over pins extending from the lid of the motor housing, engage each side of the electric motor. A similar solution is found in CN 101204271 A to KAIDI Changzhou KAIDI Electrical. An alternative way to secure the electric motor in the housing is disclosed in CN219535794 to KAIDI Changzhou KAIDI Electrical. Here, the gear bracket, connected to the front end of the electric motor, is secured with screws directly into the bottom of the motor housing.A common disadvantage of the above ways to arrange and mount the electric motor and the gear in the motor housing of the lifting column is that they rely on manual handling. Furthermore, additional manual operations are required to preassemble components and arrange printed circuit boards, wires, sockets and plugs. These lifting columns are therefore costly to manufacture and unsuited for automated assembly by, for example, a robot.

[0006] The purpose of the invention is to provide a lifting column which does not suffer from the drawbacks mentioned above, and which can be assembled in a simple and easy manner.

[0007] This is achieved according to the invention where the lifting column comprises at least two mutually telescopically arranged profiles, a box-shaped housing fixed to one of the telescopically arranged profiles, and where the box-shaped housing has a rear end wall, a front end wall, two side walls extending between the rear end wall and the front end wall, and a bottom extending between the rear end wall, the front end wall, and the two side walls. The drive unit of the lifting column comprises an electric motor and a gear at a first end of the electric motor. The electric motor has a longitudinal axis between the first end and a second end of the electric motor. The drive unit is secured inside the box-shaped housing such that the first end of the electric motor faces the front end wall of the box-shaped housing and the second end of the electric motor faces the rear end wall of the box-shaped housing. The spindle unit of the lifting column is arranged inside the at least two mutually telescopically arranged profiles and at least one of the at least two mutually telescopically arranged profiles is connected to the spindle unit. Further, the spindle unit is connected to the electric motor of the drive unit via the gear, and the mutually telescopically arranged profiles are, depending on the direction of rotation of the electric motor, driven in or out of each other by the spindle unit. The drive unit comprises a bracket on the second end of the electric motor, where the bracket comprises at least two flanges each extending from the electric motor towards opposing inner sides of the side walls of the box-shaped housing. The free end of each of the at least two flanges comprise a resilient pad abuttingthe inner side of the side walls of the box-shaped housing. Hereby, the drive unit appears as a single assembly which is easy to secure in the box-shaped housing, as the gear just needs to engage with the spindle unit and the pads aligned with the inner sides of the side walls of the box-shaped housing.

[0008] In an embodiment, the drive unit further comprises an electro-mechanical locking mechanism comprising a relay having a nonrotating locking element and a locking sleeve on the axle of the second end of the electric motor, a printed circuit board connected to the relay, and a relay cover in which the printed circuit board is fixed. The relay cover is configured to engage with and be secured to the bracket, and the printed circuit board is positioned between the relay cover and the second end of the electric motor. Hereby, the electromechanical locking mechanism can very easily be added to the lifting column.

[0009] In an embodiment, the drive unit further comprises a locking clip fixed in the bracket, which engages the relay cover. Hereby, disengagement of the relay cover from the bracket is prevented. Furthermore, the locking clip serves to ensure that the relay cover has been mounted correctly.

[0010] In an embodiment, the bracket of the drive unit comprises an opening through which the locking clip can extend from its engagement with the relay cover to engage with the outer surface of the enclosure of the electric motor. Hereby, the locking clip can be pushed along the side of the enclosure of the electric motor, through the opening and into engagement with the relay cover.

[0011] In an embodiment of the drive unit, the locking clip is made of metal. Further, the printed circuit board comprises an electric conducting trace engaging with the locking clip through the opening between the bracket and the relay cover. By including this in the drive unit, the electric motor can be connected to ground.

[0012] In an embodiment, the drive unit further comprises a socket connected to the printed circuit board. The rear end wall of the box-shaped housing comprisesa slot configured to receive the socket. Hereby, it is possible to connect the drive unit to power and / or a controller without having any wires to be guided or arranged inside the box-shaped housing.

[0013] In an embodiment, the bracket of the drive unit comprises at least two stops, each extending from the electric motor towards opposing inner sides of the side walls of the box-shaped housing. The outer end of each of the stops terminates at a distance from the inner sides of the side walls of the boxshaped housing. When either of the outer ends of the stops engage the adjacent inner side of the side wall of the box shaped housing, the displacement or rotation of the drive unit centered in the longitudinal axis of the spindle unit is limited.

[0014] In an embodiment of the drive unit, in a plane extending perpendicular to the longitudinal axis of the spindle unit, the distance between the side of the socket to an adjacent side of the slot in the rear end wall of the box-shaped housing is greater than the distance between the outer end of the stop and the inner side of the side wall of the box-shaped housing. Hereby, the limit to the displacement or rotation of the drive unit provided by the stops prevents the socket from colliding with the side wall of the slot. The socket, as well as the printed circuit board, is hereby protected.

[0015] In an embodiment of the drive unit, the bracket comprises slots which are configured to receive and engage with corresponding pins of the relay cover. This guides the mounting of the relay cover and thereby ensures correct and failsafe mounting.

[0016] In an embodiment of the drive unit, the electric motor comprises terminals extending out of the second end of the electric motor, and the printed circuit board comprises fuse clips connected to the terminals. Further, the relay and the fuse clips are connected to the side of the printed circuit board facing away from the second end of the electric motor. In addition, the printed circuit board comprises slits through which a part of the terminals of the electric motor canextend and a hole through which the looking sleeve of the axle of the electric motor can pass through. These slits and the hole serve to facilitate the mounting of the relay cover to the bracket and provide a solution free of electric wires that need to be guided or arranged inside the box-shaped housing.

[0017] An embodiment of the invention will be described more fully below with reference to the accompanying drawings, in which:

[0018] Figs. 1a and 1b illustrate a lifting column respectively in a perspective and in a rear view,

[0019] Fig. 2 illustrates in a side view the lifting column of figs. 1 a and 1 b without the mutually telescopically arranged profiles,

[0020] Fig. 3 illustrates in a perspective the lifting column of figs. 1a and 1b without the box-shaped housing,

[0021] Fig. 4 illustrates in a perspective the lifting column of figs. 1a and 1b without the box-shaped housing and the mutually telescopically arranged profiles,

[0022] Fig. 5 illustrates in a perspective the drive unit and the box-shaped housing of the lifting column both seen from the top,

[0023] Fig. 6 illustrates in a perspective of the drive unit seen from the bottom and the box-shaped housing of the lifting column seen from the top,

[0024] Fig. 7 illustrates a top view of the drive unit secured in the box-shaped housing of the lifting column,

[0025] Fig. 8 illustrates in perspective the drive unit secured in the box-shaped housing of the lifting column seen from the top,

[0026] Figs. 9a to 9c illustrate a top view of the drive unit and in steps how the relay cover is secured to the bracket of the electric motor of the lifting column,Fig. 10 illustrates in perspective the drive unit seen from the top,

[0027] Fig. 11 illustrates in perspective the drive unit seen from the bottom,

[0028] Fig. 12 illustrates in perspective the drive unit without the relay cover and the printed circuit board seen from the top,

[0029] Fig. 13 illustrates in perspective the drive unit without the relay cover and the printed circuit board seen from the bottom,

[0030] Fig. 14 illustrates in perspective the drive unit seen from the rear, and

[0031] Fig. 15 illustrates in perspective the drive unit without the relay cover seen from the rear end.

[0032] Figs. 1 to 3 show a lifting column 1 comprising three mutually telescopically arranged profiles 2,3,4 and box-shaped housing 5 fixed to one of the telescopically arranged profiles 2,3,4. The box-shaped housing 5 has rear end wall 5a, a front end wall 5b, and two side walls 5c, 5d extending between the rear end wall 5a and the front end wall 5b. Further, a bottom 5e of the boxshaped housing 5 extends between the rear end wall 5a, the front end wall 5b, and the two side walls 5c, 5d, In the present case, the bottom 5e of the boxshaped housing 5 is fixed to the top of the innermost profile 2. In an alternative embodiment, the box-shaped housing 5 could be fixed to the outermost profile 4. The lifting column 1 is driven by a drive unit 6 comprising an electric motor 7 and a gear 8 arranged at a first end of the electric motor 7. The electric motor describes a longitudinal axis between the first end and a second end of the electric motor 7. The drive unit 6 is secured inside the box-shaped housing 5 such that the first end of the electric motor 7 faces the front end wall 5b of the box-shaped housing 5, and the second end of the electric motor 7 faces the rear end wall 5a of the box-shaped housing 5.

[0033] Through a hole 9 in the bottom 5e of the box-shaped housing 5, the gear 8 of the drive unit 6 engages a spindle unit 10 arranged inside the three mutuallytelescopically arranged profiles 2,3,4. The spindle unit 10 comprises a drive tube 11, a hollow spindle 12, and a solid spindle 13. These three elements of the spindle unit 10 engage each other either directly or indirectly. The spindle unit 10 is connected to one or more of the three profiles 2,3,4. When activated, the electric motor 7 rotates the drive tube 11 via the gear 8, upon which the hollow spindle 12 is also rotated, causing it to travel along the solid spindle 13, which is fixed against rotation to the bottom of the profile 4. In this way, the mutually telescopically arranged profiles 2,3,4 can, depending on the direction of rotation of the electric motor 7, be driven in or out of each other. In the drawings, the lifting column is shown with three mutually telescopically arranged profiles 2,3,4, however, a lifting column can also be configured with only two profiles or more than three.

[0034] The drive unit 6 further comprises a bracket 14 mounted on the second end of the electric motor 7, such that the bracket 14 extends a distance over the enclosure of the electric motor 7. The bracket 14 comprises two flanges 15,16 which each, from the electric motor 7, extend in a direction towards the inner sides of the side walls 5c, 5d of the box-shaped housing 5. The end of each of the flanges 15,16 comprises resilient pads 17,18 adapted for engagement with the inner sides of the side walls 5c, 5d of the box-shaped housing 5. By having the gear 8 engage the spindle unit 10 and the pads 17,18 abut the inner sides of the side walls 5c, 5d of the box-shaped housing 5, the drive unit 6 can be secured inside the box-shaped housing 5. When the electric motor 7 is activated, the inertia of the gear 8, the spindle unit 10 and the mutually telescopically arranged profiles 2,3,4 will, centered in the longitudinal axis of the spindle unit 10, cause the drive unit 6 to displace towards one of the inner sides of the side walls 5c, 5d of the box-shaped housing 5 against which the pads 17,18 of the flanges 15,16 abut. Because the displacement is centered in the longitudinal axis of the spindle unit 10, the drive unit 6 is rotated, but only a very small distance. The second end of electric motor 7 of the drive unit 6 travels the longest distance as this is the part situated furthest away from the axis of rotation of the spindle unit 10. This movement will take place along a plane perpendicular to the longitudinal axis of the spindle unit 10 and themutually telescopically arranged profiles 2,3,4. Depending on the direction of rotation of the electric motor 7, it will either be the flange 15 with pad 17 or the flange 16 with pad 18 that will be pressed towards their respective inner side of a side wall 5c, 5d of the box-shaped housing 5. The resilient pads 17,18 are made of a material having a resilience which only allows a small displacement of the electric motor 7 inside the box-shaped housing 5 and could for example be made of rubber, foam, or foam rubber.

[0035] On the surface facing the inner side of the side wall 5c, 5d of the box-shaped housing 5, the pads 17,18 comprise small protrusions 17a, 18a, which can accommodate any tolerances of the dimensions of the box-shaped housing 5 and ease the assembly of the drive unit 6 when securing it inside the boxshaped housing 5. Once secured, the pads 17,18 absorb and dampen the vibrations of the drive unit 6 when the electric motor 7 is activated.

[0036] The pads 17,18 can extend underneath the bottom of the electric motor 7. A separate bottom pad 19 can also be placed on the underside of the bracket 14 facing the bottom 5e of the box-shaped housing 5. Apart from the above-mentioned effect on vibrations, the pads facing and abutting the bottom 5e of the box-shaped housing 5 also ensure that the enclosure of the electric motor 7 does not engage or make contact with the bottom 5e of the box-shaped housing 5.

[0037] The drive unit 6 comprises an electro-mechanical locking mechanism, disclosed in WO2021244715 to LINAK A / S, for braking or locking of the rotation of the electric motor 7 and thereby the spindle unit 10 of the lifting column 1. The electro-mechanical locking mechanism comprises a solenoid, here in the form of a relay 20 having a nonrotating locking element 21, which is displaceable by the relay 20 and arranged to engage one of the cams on a rotating locking element in the form of a locking sleeve 22 fixed to the axle 23 of the second end of the electric motor 7. The relay 20, including the nonrotating locking element 21, is placed on a printed circuit board 24, whichis fixed in a relay cover 25 such that the relay 20 is positioned between the printed circuit board 24 and the inside of the relay cover 25.

[0038] The relay cover 25 with the printed circuit board 24 appears as an assembly, which can be secured to the bracket 14. To do so, the relay cover 25 is first brought to engage the bracket 14 such that the relay 20 is aligned next to the locking sleeve 22. In this position, protruding pins 26 of the relay cover 25 are placed just outside the open end of a corresponding number of slots 27 on the bracket 14. Then, the relay cover 25 is slid sideways such that the protruding pins 26 are guided by and fixed into the slots 27 on the bracket 14, whereby the nonrotating locking element 21 of the relay 20 is moved towards engagement with the locking sleeve 22 on the axle 23 of the second end of the electric motor 7. As a final step, a locking clip 28 is slid through an opening 29 in the bracket 14 such that the part of the locking clip 28 protruding out of the opening 29 engages the outside of the relay cover 25 and acts like a stop, which prohibits the relay cover 25 from disengaging from the bracket 14.

[0039] The locking clip 28 is made of spring steel and, on the opposite side of the bracket 14, engages the enclosure of the electric motor 7. Apart from engaging the outside of the relay cover 25, the locking clip 28 also engages a trace of the printed circuit board 24, as seen in figure 15. Hereby, the ground connection of the electric motor 7 is made via the printed circuit board 24.

[0040] To establish an electric connection to the terminals 30 of the electric motor 7, the printed circuit board 24 comprises corresponding fuse clips 31. The relay 20 and the fuse clips 31 are all placed on the side of the printed circuit board 24 facing away from the second end of the electric motor 7. Therefore, the printed circuit board 24 comprises throughgoing slits 32 for the fuse clips 31 to pass through, as well as a hole 33 that the locking sleeve 22 on the axle 23 of the electric motor 7 can pass through.

[0041] The printed circuit board 24 comprises a socket 34 for connecting the electric motor 7 to a power supply and / or a controller. The socket 34 protrudes out ofan opening in the rear of the relay cover 25. When the drive unit 6 is secured inside the box-shaped housing 5 of the lifting column 1 , the socket 34 is aligned in a slot or cut-out 35 of the rear end wall 5a of the box-shaped housing 5. Since the drive unit 6 can displace during activation of the electric motor 7, the width of the slot 35 is a bit larger than the width of the socket 34. To avoid that the socket 34 collides with the sides of the slot 35 and thereby damages the socket and the printed circuit board, the bracket 14 comprises two stops 36,37 which extend in opposite directions away from the electric motor 7, such that they, just like the pads 17,18, face the inner side of the side walls 5c, 5d of the box-shaped housing 5. When either of the stops 36,37 engage the inner side of a side wall 5c, 5d of the box-shaped housing 5, further rotation of the drive unit 6 is prevented. This happens when the rotation of the drive unit 6 causes a compression of the pads 17,18 to an extent which allows one of the stops 36,37 to engage either of the inner sides of a side wall 5c, 5d of the box-shaped housing 5.

[0042] By having the terminals 30 of the electric motor 7 directly connected to the fuse clips of the printed circuit board 24 and having the socket 34 directly on the printed circuit board, the drive unit 6 as a whole has no wires that need to be guided or in any other way arranged inside the box-shaped housing 5.

Claims

Claims:

1. A lifting column (1) comprising:at least two mutually telescopically arranged profiles (2,3,4), a box-shaped housing (5) fixed to one of the telescopically arranged profiles (2,3,4),where the box-shaped housing (5) has rear end wall (5a), a front end wall (5b), two side walls (5c, 5d) extending between the rear end wall (5a) and the front end wall (5b), and a bottom (5e) extending between the rear end wall (5a), the front end wall (5b), and the two side walls (5c, 5d),a drive unit (6) comprising an electric motor (7) and a gear (8) at a first end of the electric motor (7),the electric motor (7) describing a longitudinal axis between the first end and a second end of the electric motor (7),where the drive unit (6) is secured inside the box-shaped housing (5) such that the first end of the electric motor (7) faces the front end wall (5b) of the box-shaped housing (5) and the second end of the electric motor (7) faces the rear end wall (5a) of the box-shaped housing (5), a spindle unit (10) arranged inside the at least two mutually telescopically arranged profiles (2,3,4) and where at least one of the at least two mutually telescopically arranged profiles (2,3,4) are connected to the spindle unit (10),where the spindle unit (10) is connected to the electric motor (7) of the drive unit (6) via the gear (8),and where the mutually telescopically arranged profiles (2,3,4), are driven in or out of each other by the spindle unit (10) depending on the direction of rotation of the electric motor (7),characterized in thatthe drive unit (6) comprises a bracket (14) on the second end of the electric motor (7), where the bracket (14) comprises at least two flanges (15,16) each extending from the electric motor (7) towards opposing inner sides of the side walls (5c, 5d) of the box-shaped housing (5),where the free end of each of the at least two flanges (15,16) comprises a resilient pad (17,18) abutting the inner side of the side walls (5c, 5d) of the box-shaped housing (5).

2. Lifting column (1) according to claim 1 where the drive unit (6) further comprises:an electro-mechanical locking mechanism comprising a relay (20) having a nonrotating locking element (21) and a locking sleeve (22) on the axle (23) of the second end of the electric motor (7),a printed circuit board (24) connected to the relay (20),a relay cover (25) in which the printed circuit board (24) is fixed, and where the relay cover (25) is configured to engage with and be secured to the bracket (14), and where the printed circuit board (24) is positioned between the relay cover (25) and the second end of the electric motor (7).

3. Lifting column (1) according to claim 2, characterized in that the drive unit (6) further comprises a locking clip (28) fixed in the bracket (14), where the locking clip (28) engages the relay cover (25) to prevent disengagement of the relay cover (25) from the bracket (14).

4. Lifting column (1) according to claim 3, characterized in that the bracket (14) comprises an opening (29) through which the locking clip (28) can extend from its engagement with the relay cover (25) to engagement with the outer surface of the enclosure of the electric motor (7).

5. Lifting column (1) according to claim 4, characterized in that the locking clip (28) is made of metal, and where the printed circuit board (24) comprises an electric conducting trace engaging the locking clip (28) through the opening (29) between the bracket (14) and the relay cover (25).

6. Lifting column (1) according to claims 1 and 2 characterized in that the drive unit (6) further comprises a socket (34) connected to the printed circuitboard (24), and where the rear end wall (5a) of the box-shaped housing (5) comprises a slot (35) configured to receive the socket (34).

7. Lifting column (1) according to any one of the above claims, characterized in that the bracket (14) comprises two stops (36,37), each extending from the electric motor (7) towards the inner side of the side walls (5c, 5d) of the box-shaped housing (5), and where the outer end of the stops (36,37) terminate at a distance from the inner side of the side walls (5c, 5d) of the box-shaped housing (5).

8. Lifting column (1) according to claim 6 and 7, characterized in that, in a plane extending perpendicular to the longitudinal axis of the spindle unit (10), the distance between the side of the socket (34) to the side of the slot (35) in the rear end wall (5a) of the box-shaped housing (5) is greater than the distance between the outer end of the stop (36,37) and the inner side of the side wall (5c, 5d) of the box-shaped housing (5).

9. Lifting column (1) according to claim 2, characterized in that the bracket (14) comprises slots (27), and where the relay cover (25) comprises protruding pins (26) configured to be received in the slots (27).

10. Lifting column (1) according to claim 2, characterized in that the electric motor (7) comprises terminals (30) extending out of the second end of the electric motor (7), where the printed circuit board (24) comprises fuse clips (31) connected to the terminals (30), where the relay (20) and the fuse clips (31) are connected to the side of the printed circuit board (24) facing away from the second end of the electric motor (7), and where the printed circuit board (24) comprises slits (32) through which a part of the terminals (30) of the electric motor (7) can extend and a hole (33) through which the looking sleeve (22) of the axle (23) of the electric motor (7) can pass through.

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