Drive for mechanical adjustment of profile parts; piece of furniture, profile part and method for manufacturing a profile part

Abstract: The invention relates to a drive for mechanically displacing and positioning two profile parts (2,6) relative to each other, comprising: at least one tooth path (4,5) connected to a one profile part (6), at least one toothed wheel (13,14) connected rotatably to a second profile part (2) for engaging on the tooth path, drive means (7), and a transmission mechanism for transmitting to the toothed wheel the power produced by the drive means, wherein the transmission mechanism is provided with at least one right-angled transmission. The invention also relates to a piece of furniture provided with such a drive, a profile part for assembly with the drive and a method for manufacturing such a profile part.

Description: The invention relates to a drive for mechanically displacing and positioning two profile parts relative to each other, comprising: at least two tooth paths connected to a first profile part, at least two toothed wheels connected rotatably to a second profile part for engaging on the tooth paths, drive means, and a transmission mechanism for transmitting to the toothed wheels the power produced by the drive means, wherein the transmission mechanism is provided with at least one right-angled transmission. The invention also relates to a piece of furniture provided with at least one leg comprising two telescopically co-acting profile parts, and to use of a drive according the present invention. Finally, the invention also relates to a method for manufacturing such a profile part comprising at least two tooth paths, wherein in a first step A) the profile is extruded. Many solutions are known for height adjustment of objects, such as for instance tables, beds, machines and so on. Many of the applied constructions comprise one or more telescopic legs, the length of which is adjustable using for instance a screw spindle or toothed belt. A drawback of the existing mechanised drives for adjustment of the telescopic legs is that these are complex and therefore costly. An additional drawback is that the existing drives are generally bulky. The international patent application WO 99/16333 discloses a linear actuator that comprises at least two racks connected to an outer section and an inner section with at pinions engaging on the racks. In the inner structure a motor is mounted that is linked with the pinions for operating the actuator. The linear actuator as disclosed is operating as expected, but the problem with this linear actuator is that it is a heavy and complex construction that requires a lot of space. The present invention has for its object to provide a drive for displacing and positioning two profile parts relative to each other with which inter alia telescopic legs are adjustable without the above stated drawbacks of the prior art. The invention also has for its object to provide a relatively low-noise drive. In addition, the invention has the object of providing a piece of furniture provided with at least one such drive, a profile part for assembly with the drive and a method for manufacturing a profile part with which a compact, inexpensive and low-noise application of the drive is possible. The invention provides for this purpose a drive as disclosed in the preamble of claim 1, characterised in that the tooth paths are located on substantially opposite sides of the first profile part such that the tooth paths face one another. Preferably the drive has toothed wheels that are placed substantially parallel to each other, which toothed wheels are rotatable in opposing directions and on opposite longitudinal sides of the second profile part engage on respective tooth paths of the first profile part. A tooth path connected longitudinally to the profile part is also described as a gear rack. Through the engagement of the toothed wheels on the tooth paths that face one another the drive by itself provides rigidity to an assembly of profile parts in which the drive is incorporated. In addition, the transmission can take a compact form; retaining means as disclosed in WO 99/16333 are after all unnecessary as the toothed wheels in combination with the tooth paths already provide this function. The component which is longer, the tooth path, can easily be integrated into the first profile part; a method for this easy integration will be discussed later in this publication and is also part of the present invention. The facing tooth paths according the present invention can be constructed more compact, and provide more stability to the drive, than the tooth paths (racks) according the prior art which tooth paths, if located on opposite sides of a first profile part, are directed in the same direction and thus principally perpendicular to the inner walls of the first profile part. This is one of the reasons why in the present invention the second profile part can fit closely in the first profile part. The width of the tooth racks is not limited in the construction of the invention; even an very broad tooth rack (for instance for dealing with heavy loads on the drive) can be realised without influencing the compactness of the drive construction. An additional advantage is that the length range over which adjustment is possible is limited to only a small extent by the construction height of the drive. The use of the right-angled transmission in the transmission mechanism has the advantage that a load on the transmission mechanism is taken up without this resulting in loading of the drive means. The transmission can hereby also be compact and inexpensive; separate measures for fixation of the transmission are unnecessary without this resulting in a considerable limitation of the efficiency of the transmission. A consequence hereof is that the drive means can also be kept compact, this furthermore being advantageous from considerations of cost and in respect of the noise produced by the drive. The drive means, the transmission mechanism and the toothed wheels are preferably located substantially within the outer periphery of the second profile part and the second profile part is preferably also telescopically movable in and out of the first profile part. The drive can thus be fitted entirely into a profile part, including nearly all of the toothed wheels that cooperate with the tooth paths. In addition to the advantage of efficient use of the generally unused inside of a profile the distance between the first and second profile part can be very limited, this resulting in a further sound-damping on the outside of the profile parts. Another advantage of the close fitting (relative to the prior art) is that the inside of the first profile part is protected from fouling and damage. These advantages are further reinforced when the second profile part is compactly enclosed by the first profile part. In another preferred embodiment the first profile part is provided with tooth paths which are substantially parallel to each other. The drive means can comprise an electric motor which is widely available at limited cost. It is however also possible to provide the drive with pneumatic drive means, hydraulic drive means etc., subject to the use of the drive. For operation of the drive means these are provided with operating means, for instance in the form of a control panel with or without wiring for use remotely of the drive. The transmission mechanism is preferably provided with a reductor formed by toothed wheels and chains so that small electric motors with a relatively high rotation speed can be applied for adjustment of heavily loaded profile parts. The invention also provides a piece of furniture provided with at least one leg comprising two telescopically co-acting profile parts characterised in that the piece of furniture is provided with a drive as described above. In a preferred application the piece of furniture has at least two length-adjustable legs, wherein the drives of the individual legs are synchronized. There is a particular need for adjustability of furniture legs. For ergonomic and aesthetic reasons among others, little space is available for placing of a drive. Particularly, though not exclusively, envisaged is the use in office furniture such as tables, desks, chairs and so on. The piece of furniture is preferably provided with a drive which engages on the first profile part such that the toothed wheels are placed under bias between two facing tooth paths of the first profile part. This results in the absence of permanent play between first profile part and drive. The drive can also be connected in simple manner without play to the second profile part. This increases the rigidity of an assembly of first profile part, drive and second profile part. The invention also comprises the use of a drive as described, said drive is provided with at least two longitudinally arranged tooth paths, which tooth paths are pressed without machining into the profile. The profile part is preferably provided with two internal tooth paths located substantially opposite and parallel to each other. Such a profile part can be manufactured from aluminium or an aluminium alloy. It is found to be financially advantageous to press or roll a tooth path into the profile part. As a result of the construction of the profile with facing tooth paths, this deformation can easily be performed cold or hot depending on the material used. While the quality of the pressed tooth path will generally be inferior to that of a machined (for instance mortised or milled) tooth path, in the application according to the invention a deformed tooth path already provides sufficient functionality. Finally, the invention provides a method for manufacturing a profile part comprising at least two tooth paths, wherein in a first step A) the profile is extruded, characterised by the successive steps of: B) pressing at least two tooth paths without machining into the profile, and C) curing the profile with tooth paths. The tooth paths are herein preferably pressed into the profile part in a single production cycle. A tooth path can thus be arranged in the profile in very economic manner. The present invention will be further elucidated with reference to the non-limitative embodiments shown in the following figures. Herein: figure 1a shows a top view of an assembly of a first and second profile part and a drive according to the invention, figure 1b is a partially cut-away side view of the assembly shown in figure 1a, figure 2a shows a top view of two telescopic profile parts, figure 2b shows a side view of the profile parts shown in figure 2a, and figure 3 shows a schematic side view of a preferred embodiment of the drive according to the invention. Figure 1a shows an assembly 1 of a drive 3 which is connected to a second profile part 2 and which engages on two tooth paths 4,5 forming part of a first profile part 6. Via a right-angled transmission (not shown in this figure) accommodated in a housing 8 a schematically indicated electric motor 7 drives a tooth wheel 9 (see figure 1b), the axis of which lies perpendicularly of the longitudinal direction of profile parts 2,6. As shown in figure 1b, tooth wheel 9 engages on a larger tooth wheel 10. A third tooth wheel 12 is fixed to the same shaft 11 as the larger tooth wheel 10. This third tooth wheel 12 is emphatically smaller than the larger tooth wheel 10. The third tooth wheel 12 engages in turn on the larger outer periphery of a toothed wheel 13. Toothed wheel 13 drives an equally large second toothed wheel 14. Toothed wheels 13,14 engage respectively in tooth paths 4,5 of the first profile part 6. For protection of drive 3 in the U-profile 2 (this is the second profile part 2), this latter is covered with a plate 15. The transmission of respectively the tooth wheels 9,10,12,14 provides drive 3 with a reduction factor. A desired reduction factor can be chosen depending on the type of electric motor 7 and the use of assembly 1. In order to prevent play in the plane through toothed wheels 13,14, these wheels 13,14 are preferably placed under bias between tooth paths 4,5. A guide element 16 is arranged in the first profile part 6 in-order to prevent play on toothed wheels 13,14 in axial direction. Figure 2a shows a cross-section through a first tubular profile 17 and a second tubular profile 18 slidable therein. The first tubular profile 17 is provided with two internal tooth paths 19,20 for engagement thereon of a drive according to the invention. Figure 2b shows a side view of the tubular profile parts 17,18 in a relatively extended situation. A drive 21 to be described with reference to figure 3 can be arranged in the second tubular profile 18 so as to change the total length of the two tubular profiles 17,18. The visible sides of tubular profile parts 17,18 can be embodied completely flat; tooth paths 19,20 are situated on the non-visible inside of the first tubular profile 17. In addition to the fact that this provides visual screening of tooth paths 19,20, they are also protected from fouling and damage. Figure 3 shows a schematically depicted drive 21 with an electric motor 22 which is fixed to a support plate 23. An output shaft 24 of electric motor 22 engages as pinion on a tooth wheel 25. A tooth wheel 26 of smaller diameter than tooth wheel 25 is mounted on the shaft of tooth wheel 25. Tooth wheel 26 drives a subsequent tooth wheel 28 by means of a chain 27. Similarly to tooth wheel 25, tooth wheel 28 is likewise combined with a smaller tooth wheel 29 which once again drives a subsequent tooth wheel 31 with a chain 30. Finally, similarly to tooth wheels 25 and 28, a toothed wheel 33 is driven by a tooth wheel 32 combined with tooth wheel 31. Toothed wheel 33 drives an equally large toothed wheel 34. Toothed wheels 33,34 project to a limited extent from support plate 23. It is precisely where they project that they can engage on tooth paths 19,20 of a first tubular profile 17 (see figure 2a). Support plate 23 and/or electric motor 22 can be mounted entirely in the second tubular profile, the toothed wheels 33,34 must however protrude outside the second tubular profile 18 such that they can engage on tooth paths 19,20. Slots (not shown) can for instance be milled for this purpose in the second tubular profile 18. It is noted that toothed belts or smooth belts or cords can for instance be applied instead of chains 27,30. Although the invention is elucidated with reference to only a few embodiments, it will be apparent to all that the invention is in no way limited to the described and shown embodiments. On the contrary, for the skilled person many other variations are possible within the scope of the invention as defined by the appended claims.

Claims: Drive (3, 21) for mechanically displacing and positioning two profile parts (2, 6; 17, 18) relative to each other, comprising: at least two tooth paths (4, 5; 19, 20) connected to a first profile part (6, 17), at least two toothed wheels (13, 14; 33, 34) connected rotatably to a second profile part (2, 18) for engaging on the tooth paths (4, 5; 19, 20), drive means (7, 22), and a transmission mechanism for transmitting to the toothed wheels (13, 14; 33, 34) the power produced by the drive means (7, 22), wherein the transmission mechanism is provided with at least one right-angled transmission, characterised in that the tooth paths (4, 5; 19, 20) are located on substantially opposite sides of the first profile part (6, 17) such that the tooth paths (4, 5; 19, 20) face one another. Drive (3, 21) as claimed in claim 1, characterised in that the toothed wheels (13, 14; 33, 34) are placed substantially parallel to each other, are rotatable in opposing directions and on opposite longitudinal sides of the second profile part (2, 18) engage on respective tooth paths (4, 5; 19, 20) of the first profile part (6, 17). Drive (3, 21) as claimed in claim 1 or 2, characterised in that the drive means (7, 22), the transmission mechanism and the toothed wheels (13, 14; 33, 34) are located substantially within the outer periphery of the second profile part (2, 18). Drive (3, 21) as claimed in any of the foregoing claims, characterised in that the second profile part (2, 18) is telescopically movable in and out of the first profile part (6, 17). Drive (3, 21) as claimed in any of the foregoing claims, characterised in that the two tooth paths (4, 5; 19, 20) are located substantially parallel to each other. Drive (3, 21) as claimed in any of the foregoing claims, characterised in that the drive means (7, 22) comprise an electric motor. Drive (3, 21) as claimed in any of the foregoing claims, characterised in that the drive means (7, 22) are provided with operating means. Drive (3, 21) as claimed in any of the foregoing claims, characterised in that the transmission mechanism comprises a reductor formed by toothed wheels (9, 10, 12, 14; 25, 26, 28, 29, 31, 32) and chains (27, 30). Piece of furniture provided with at least one leg comprising two telescopically co-acting profile parts (2, 6; 17, 18), characterised in that the piece of furniture is provided with a drive (3, 21) as claimed in any of the foregoing claims. Piece of furniture as claimed in claim 9, characterised in that the piece of furniture is provided with at least two length-adjustable legs, wherein the drives (3, 21) of the individual legs are synchronized. Piece of furniture as claimed in claim 9 or 10, characterised in that the drive (3, 21) engages on the first profile part (6, 17) such that the toothed wheels (13, 14; 33, 34) are placed under bias between two tooth paths (4, 5; 19, 20) of the first profile part (6, 17). Use of a drive (3, 21) as claimed in any of the claims 1-8, characterised in that the profile part (6, 17) is provided with at least two longitudinally arranged tooth paths, (4, 5; 19, 20) which tooth paths (4, 5; 19, 20) are pressed without machining into the profile (6, 17). Use of a drive (3, 21) as claimed in claim 12, characterised in that the profile part (6, 17) is provided with two internal tooth paths (4, 5; 19, 20) located substantially opposite and parallel to each other. Use of a drive (3, 21) as claimed in claim 12 or 13, characterised in that the profile part (6, 17) is manufactured from aluminium or an aluminium alloy. Method for manufacturing the first profile part (6, 17) of a drive according to any of claims 1-8, comprising at least two tooth paths (4, 5; 19, 20), wherein in a first step A) the profile is extruded, characterised by the successive steps of: B) pressing at least two tooth paths (4, 5; 19, 20) without machining into the profile, and C) curing the profile with tooth paths (4, 5; 19, 20). Method as claimed in claim 15, characterised in that the tooth paths (4, 5; 19, 20) are pressed into the profile part (6, 17) in a single production cycle.

Inventors: STOELINGA DIRK JAN, STOELINGA, DIRK JAN
Applicants: ACTUALL BV, ACTUALL B.V.
Application year: 1999
Main classification: A47B9
IPC codes: A47B9, A47C17