DE9404383U1 - Electromotive adjustment drive - Google Patents

Description

Patent Attorneys" 18/9 Dr. Loesenbeck

Dipl.-Ing. Stracke Dipl.-Ing. Loesenbeck

. Jöllenbecker Str. 164, 33613 Bielefeld 1

Description

Dewert Drive and System Technology GmbH & Co. KG Weststrasse 1, 32278 Kirchlengern

Electromotoric adjustment drive

The present invention relates to an electromotive adjustment drive, in particular a furniture drive with a ¹ · drive motor, a gear that reduces the speed of the drive motor, with a spindle that can be driven in rotation by the gear, on which a spindle nut that is secured against rotation and can be moved in the longitudinal direction of the spindle is placed for displacing a lifting tube in its longitudinal axis, which is guided in a flange tube, and with a housing on which a connection part is attached on the outside, preferably in the form of a fork head. The electromotive adjustment drive in question is also used in the care and hospital sectors, among other places.

A drive in question is known, for example, from DE 8801074 Ul- and DE 8903603 Ul. This adjustment

. drives are used, among other things, to swivel the adjustable parts of a slatted frame, a lounger or an armchair. These drives must therefore be extremely compact. In addition, they should be inexpensive to manufacture. In the electromotive adjustment drives known to date, the electric drive motor is flanged to the housing. As a result, the drive motor contains a zinc-plated steel housing.

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die-cast or plastic housing. The housing of the adjustment drive is also divided, i.e. it consists of at least two housing parts that are connected by connecting elements, for example by screws. The adjustment drives in question have proven themselves very well in practice, but it is. "disadvantageous is that the cost of manufacturing and assembly is quite high. It is also necessary that the center distances of the adjustment drives are maintained extremely precisely, since the dimensions of the gear components are very small. The gear is usually a worm gear, since the ratio of the speeds in these gears is very high. The worm wheel of this worm gear is mounted on the spindle in a rotationally fixed manner. The spindle nut is usually provided with several webs distributed around the circumference, which engage in internal guide grooves in the flange tube. The spindle nut is firmly connected to the lifting tube, which is also guided. The connecting part arranged on the outside of the housing, for example the fork head, is used to hang the electromotive adjustment drive. This connecting part is opposite the outer free end of the lifting tube. Another connecting part, for example a fork head, is usually mounted on the free end of the lifting tube in a rotationally fixed manner. A lever, which can be part of a fitting on the furniture, is connected to this fork head.

The object of the present invention is to design an electromotive adjustment drive of the type described at the outset in a structurally simple manner so that the overall manufacturing costs are reduced, that it is designed to be easy to assemble, and that the smallest possible number of fastening elements, such as screws, are necessary to secure the components of the adjustment drive.

5 The task is solved by forming the housing of the electromotive adjustment drive in one piece

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and contains a motor mounting ring that can be closed with a cover.

Because the housing is made from one piece, it is now possible to maintain the gear's center distances extremely precisely. In addition, the housing can be manufactured using a single tool, as it is usual to manufacture these housings using zinc die casting or plastic injection molding. When assembling the adjustment drive, the two housing parts do not need to be connected. As the housing also contains the motor mounting ring, a fan motor without a housing can be used, which is correspondingly cheaper than the drive motors required in the state of the art. The motor is flanged to an appropriately designed inner surface of the motor mounting ring, for example. Two screws are required for this. As the center distances are extremely precise, better running is achieved for the meshing parts, for example the worm with the worm wheel. This reduces losses, i.e. efficiency is increased. This is an extremely important factor for the performance of the adjustment drives in question. In addition, the adjustment drive according to the invention results in an extremely short installation length which is particularly important for furniture in the care and hospital sectors. . ■

The housing is also provided with a bracket for the positive and/or force-fitting fixing of the flange pipe.

This allows the flange pipe to be cut to length from a rod, so that the connection by means of a thread according to the state of the art is no longer necessary. The flange pipe is expediently

a profile tube with an irregular cross-section so that it can be inserted into the holder in a form-fitting manner. The flange tube is expediently a section of an aluminum profile tube. The holder for the flange tube is expediently designed in the manner of a clamp,

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which is part of the housing. This allows the flange pipe that is inserted into the bracket to be secured by tightening at least one screw. The clamp has a longitudinal cut on one side through which the screw passes. To ensure a positive locking, the bracket is provided with a longitudinal groove that extends from the inside to the outside and into which a web of the flange pipe engages.

The installation conditions for the adjustment drives in question are often extremely tight. It is therefore intended that the housing has a holder for the connecting part, which describes a regular polygon in cross-section, and that the connecting part has a connecting plate that can be inserted into the holder at different angular positions. Depending on the number of corners of the polygon, the connecting part can then be fixed at an angle in relation to the opposite connecting part that is placed on the lifting tube. The polygon is expediently provided with 16 corners. The holder is a recess in a particularly simple design. This ensures that the surface is flush with the connection plate if the thickness is appropriate.

In order to keep the noise level of the drive to a minimum, a drive pinion or worm is mounted on the motor shaft of the drive motor in a rotationally fixed manner, and the free end of the motor shaft is mounted in a bearing seat of the gear housing by means of a bearing. This provides additional support for the free end so that the components that are in engagement with one another cannot shift, even if only slightly. A worm is usually mounted on the motor shaft. In order to adjust it relative to the worm gear, a threaded hole is provided in the housing that is in the correct position relative to the motor shaft, into which an adjusting screw that contacts the motor shaft is screwed. This creates a

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sensitive, axial adjustment is achieved. The bearing seat can be designed so that either a radial ball, roller or needle bearing or a plain bearing can be used in it. In a cheap variant, for example for the furniture industry, the plain bearing is used. For nursing or hospital beds, where higher forces have to be transmitted, the roller bearing is used. The motor can be designed for the respective application, determined by the buyer or customer.

Since the adjustment drive in question is equipped with a control unit, it is intended that, in order to simplify the attachment to the housing, preferably on the side opposite the motor mounting ring and parallel and at a distance from the spindle, the housing has two parallel and spaced-apart undercut grooves that can be gripped by webs of a control unit that can be attached to the housing. The webs work together to form a dovetail guide. The previously mentioned connecting part or the mount is perpendicular to the spindle. This means that it is parallel and at a distance from the motor shaft. On the side facing the mount for the connecting part, the grooves are expediently open so that the control unit can be inserted into the grooves from this side. The securing without screws can then be carried out by the connecting plate of the connecting part.

_s Since a simple assembly is desired, the housing is constructed in such a way that the spindle can be inserted from both sides, ie from the side of the lifting tube or the flange tube or from the opposite side, on which the connecting part in the form of a fork head is later fixed. It is therefore intended that the housing contains at least one bearing chamber in the form of a bore, which is provided with grooves running from the inside to the outside, the

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Arrangement and quantity corresponds to the arrangement and number of outer webs of the spindle nut.

For the transmission of forces, it is particularly advantageous if the gear or worm wheel placed on the spindle has a corresponding internal thread for transmitting tensile or compressive forces; since the force is then transmitted through the flanks that come into contact. However, since the gear or worm wheel must be secured against rotation, this can be done by the usual connection using a feather key. However, to simplify things, it is also advantageous if the spindle has a slot running in the axial direction in the outer peripheral area, into which a locking pin engages. This locking pin is driven in after the gear or worm wheel has been connected to the spindle. However, the connection can also be made in the simplest way using a cross pin. Such a connection is particularly simple if the gear or worm wheel is provided with a collar that has a bore or an elongated hole into which a welding bolt fixed to the spindle engages. To ensure good guidance of the lifting tube, a guide and sealing cap is inserted into the free end of the flange tube facing away from the holder. This guide and sealing cap has a bore adapted to the lifting tube so that a sliding seat is formed. If, for reasons of space, it is not possible for the control unit to be fixed to the grooves mentioned, a further design provides that an adapter can be plugged onto the profiled flange tube in various angular positions. The flange tube is normally provided with a guide web running in the longitudinal direction. If the adapter is then provided with four internal grooves offset by 90 degrees from one another, it can be fitted onto the flange pipe in four different positions, so that different spatial arrangements of the control unit are possible. The

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The control unit is equipped with at least two batteries or rechargeable accumulators for emergency lowering.

The invention is explained in more detail with reference to the accompanying drawings.

Show it:

Figure 1 the housing of the electromotive adjustment drive as a detail in perspective view,

Figure 2 the housing according to Figure 1 with a view of the motor mounting ring in the direction of arrow II in Fig. 1,
15

Figure 3 is a plan view corresponding to Figure 1.

Figure 4 shows the housing according to Figure 2 in longitudinal section with

View into the engine mounting ring, 20

Figure 5 is a front view looking at the bracket for

the flange pipe in the direction of arrow V in the

Figure 1 seen,

Figure 6 shows the housing according to Figure 2 with a view of the motor fastening screws, as well as the bearing chamber for the bearing of the worm wheel with the drive spindle,

Figure 7 is a sectional view showing the bearing chamber of the housing for the armature shaft/worm,

Figure 8 the housing according to Figure 1 in a front view, looking at the fastening part, '

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Figure 9 shows the electromotive adjustment drive in a longitudinal section with a view of the fastening screws of the motor.

Figure 10 shows a detail.

The housing 10 shown in Figure 1 is designed as a one-piece molded part, which was manufactured using the zinc die-casting process or the plastic injection molding process. The housing 10 contains a motor mounting ring that is approximately circular in cross-section and whose longitudinal axis is perpendicular to the spindle 12 (Figure 9). The housing 10 is also equipped with a holder 13 designed like a clamp, whose longitudinal axis is perpendicular to the longitudinal axis of the motor mounting ring 11, i.e. this longitudinal axis coincides with the central longitudinal axis of the spindle 12. On the side facing the holder 13, the motor mounting ring 11 is provided with a U-shaped extension. The holder 13 is provided with a longitudinal groove 14 that extends from the circular inner area upwards or outwards. The area above the longitudinal groove 14 is provided with a longitudinal slot 15 in order to achieve the clamping effect. The holder 13 is provided with a transverse bore transverse to the longitudinal slot 15, wherein a part lying next to the longitudinal slot 15 is designed as a threaded bore in order to screw a clamping screw into it. On the side opposite the motor mounting ring 11, the housing 10 is provided with two undercut grooves 16, 17, which together form a dovetail guide. These grooves 16, 17 can be engaged by webs (not shown) of a control unit in order to ■fix the control unit to the housing 10. The webs are molded onto the housing of the control unit. A flange tube 18 is inserted into the holder 14. This flange tube 18 is a pressed aluminum or plastic profile which has been cut to length from a rod. The outer contour of the flange tube 18 matches the inner contour of the holder 13.

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The flange tube 18 therefore has a guide web running in the longitudinal direction. It can be seen from Figure 1 that the flange tube is secured by tightening the clamping screw 19. The clamping screw is identified by the reference number 19. Figure 2 shows that the housing is provided with two vertically offset holes 20, 21 at the base of the motor mounting ring 11, into which screws can be screwed to secure the drive motor (not shown). In Figure 2, two bearing seats are identified by the reference numbers 22, 23. A bearing 22a is inserted into the bearing seat 22 and another bearing 23a is inserted into the bearing seat to support the spindle 12. The worm gear 24, which is attached to the spindle 12 in a rotationally fixed manner, is located between the two bearings. The worm gear 24 meshes with a worm (not shown) that is mounted on the motor shaft in a rotationally fixed manner. The free outer end of the motor shaft is supported by a bearing (also not shown) in the form of a plain bearing or a roller bearing. For this purpose, the housing 10 is equipped with a further bearing seat 25 (Figure 7). The bearing seat 25 is spaced from the surface of the housing 10 that is associated with the grooves 16, 17. The bearing seat 25 is associated with a central threaded hole 25a into which an adjusting screw (not shown) is screwed in order to adjust the worm relative to the worm gear 24.

Figure 3 shows the position of the motor mounting ring 11 in relation to the holder 13 for the flange pipe 18. Figure 4 shows a section through the middle of the longitudinal slot 15. Figure 4 clearly shows that next to the bearing seat 22 on the side facing the holder 13, a bearing chamber 26 is provided which, according to Figures 5 and 7, is provided with three grooves 27, 28, 29 offset by an angle of 120 degrees. These grooves 27, 28, 29 are necessary in order to insert a spindle nut 13 placed on the spindle 12 through during assembly. The spindle nut 13 moves in the longitudinal direction of the spindle 12 when the spindle 12 rotates. The grooves 27, 28, 29

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27, 28, 29. It is secured against rotation by corresponding webs. Figures 4, 6 and 9 show that a connecting part in the form of a fork head 31 is attached to the housing 10. The fork head 31 is provided with a connecting plate 32, which is designed as a regular polygon with 16 corners. The housing is provided with a corresponding receptacle 33, which is designed as a recess or cutout. The fork head 31 is located on the side opposite the holder 13. It is attached to the housing by a simple locking ring 34. It can be seen from the figures that the fork head 31 can be attached to the housing in 16 different angular positions in order to take the respective installation conditions into account. Figure 8 shows that the locking ring 34 is attached to the housing 10 by 4 screws. In addition, the shape of the holder 3 3 ■ with the outer contour of a 16-sided, regular polygon can be seen here. In addition, this figure also clearly shows the undercut grooves 16, 17 for accommodating the control unit (not shown).

y Figure 9 shows that the spindle nut 30 is equipped with a collar 30a which is located on the side facing away from the worm gear 24. The end of a lifting tube 35 with a circular cross-section is firmly attached to this collar. The lifting tube 35 can be made of aluminum or plastic depending on the application and can also be cut to length from a rod. When the spindle nut 30 is at the shortest distance from the worm gear 24, the opposite free end of the lifting tube 35 protrudes a little bit from the associated end of the flange tube 18. A fork head 36 is firmly attached to the free end of the lifting tube 35. • The fork head 36 can be attached to the lifting tube 35 in a variety of ways. A particularly simple and cost-effective solution is achieved if the end area of the lifting tube has circumferential beads 35a, which fit into correspondingly designed grooves of the inserted pin of the fork head 3 6.

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grip. The beads 35a are formed using a tool. This connection is form-fitting and particularly suitable if the lifting tube 35 is made of aluminum. In order to guide the lifting tube 35 precisely at both end areas, a guide and sealing cap 37 is inserted into or fixed to the free end of the flange tube 18. Figure 9 shows that when the drive motor (not shown) rotates in the corresponding direction, the spindle nut moves away from the gear formed by the worm wheel 24 and the worm. This extends the lifting tube 35 and thus also the fork head 36. In practice, a lever of a fitting is articulated to the fork head 36 in a manner not shown in order to adjust a corresponding piece of furniture. When the drive motor rotates in the opposite direction, the spindle nut is moved in the opposite direction. The adjusted furniture component is then brought into the previous position by its own weight. Figure 9 also shows three different possibilities for the rotationally fixed connection between the worm wheel 24 and the spindle 12. It should also be mentioned that in practice only one of these possibilities is used. The simplest connection is made by providing the collar of the worm wheel 24 and the spindle 12 with cross holes into which a cross pin 40 is driven. The bearing 23a is also placed on this collar. Another possibility is that the spindle 12 is provided with an axial slot in the outer circumference into which a locking pin 39 is driven. The slot naturally extends to the front end of the spindle 12. The third possibility is that a hole or an elongated hole is located in a collar of the worm wheel 24 into which a welding bolt 4Ö fixed to the spindle 12 engages. .... ■■....

The control unit (not shown) does not necessarily have to be fixed by means of the grooves 16, 17. It is therefore conceivable that a control unit (not shown) with an inner recess

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provided adapter is placed on the flange tube 18. The contour of the recess of the adapter corresponds to the outer contour of the flange tube 18. In a further embodiment, this adapter can be provided with several grooves that are offset from one another.

• 5 which are assigned to the inner recess so that the longitudinal guide web of the flange tube 18 can optionally engage in one of the grooves. This allows the adapter to be fixed in different angular positions and thus also the control unit attached to it to the flange tube 18. Which possible arrangement of the control unit is used depends on the installation conditions. It should also be mentioned that with the adjustment device according ^to the invention the spindle 12 can also be cut to length from a rod. By cutting the three components to length the costs are reduced considerably. A further cost reduction lies in the inexpensive assembly. In a manner not shown the bearing seats 22, 23, 25 can be formed by webs arranged at an angular distance from one another.

The electromotive adjustment drive is designed so that it can be mounted with appropriate sealing agents in order to meet the conditions for use in furniture in the care and hospital sector. The seals are then

i installed in several places for such emergency situations.

The motor mounting ring 11 with the motor cover (not shown) is sealed by a tongue and groove system into which a sealing ring, for example an O-ring, can be inserted. The locking ring 34 is placed with a surface or round seal. In addition, a coupling part made of plastic or rubber is pushed onto the flange pipe 18, which also overlaps the holder 13. The guide and sealing cap . -37 is also provided with a sealing ring, for example an O-ring, in order to secure the flange pipe 18 against the lifting pipe 35.

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In the illustration according to Figure 1, the bracket 13 is designed to accommodate two clamping screws. The clamping screw 19 assigned to the free end is then used to clamp the flange tube 18. The screw facing away from the end, i.e. facing the housing 10, is long enough to also fix a control housing whose webs are inserted into the grooves 16, 17. In this case, the dovetail guide formed from the grooves 16, 17 is closed in the area of the connecting part 31 and open on the opposite side. This design offers the advantage of even easier assembly of subassemblies.

The housing 10 is designed in the area of the bearing seats 22, 23 in such a way that different types of gear can be used with a single dimension for the center distance. For example, it is possible for the gear to be both self-locking and non-self-locking. No changes to the housing 10 are required for this. For example, a self-locking worm gear requires a worm with a larger 0 diameter than a non-self-locking worm gear.

Claims (19)

-> -> -J -> &iacgr;&iacgr; ill. Dewert Protection Claims 1. Electromotive adjustment drive, in particular furniture drive with a drive motor, a gear that reduces the speed of the drive motor, with a spindle that can be driven in rotation by the gear, on which a spindle nut that is secured against rotation and can be moved in the longitudinal direction of the spindle is placed for moving a lifting tube in its longitudinal axis, which is guided in a flange tube and with a housing to which a connecting part is attached on the outside, preferably in the form of a fork head", characterized in that the housing (10) is designed in one piece and has a motor mounting ring that can be closed by a cover (11) includes. 2. Electromotive adjustment drive according to claim 1, characterized in that the housing contains a holder (13) for the positive and/or non-positive fixing of the flange tube (18). 3. Electromotive adjustment drive according to claim 3, characterized in that the flange tube (18) is designed as a profile tube with an irregular cross-section. 4. Electromotive adjustment drive according to claim 1, characterized in that the holder (13) for the flange tube (18) is designed in the manner of a clamp, which is part of the housing (10). '.■·.' . .';■·■■■ -.'·■'■' ■ ' ■ ■ 5. Electromotive adjustment drive according to claim 4, characterized in that the holder (13) has a longitudinal groove (14) projecting from the inside to the outside, into which a web of the flange tube (18) engages. ■>■>*>■>■> Dewert 6. Electromotive adjustment drive according to claim 1, characterized in that the housing (10) has a receptacle for the connecting part, which in cross section describes a regular polygon, and that the connecting part has a connecting plate (32) that can be inserted into the receptacle in different angular positions. 7. Electromotive adjustment drive according to claim 6, characterized in that the receptacle (33) is designed in the form of a recess. 8. Electromotive adjustment drive according to claim 1, characterized in that a drive pinion or a worm is mounted on the motor shaft of the drive motor in a rotationally fixed manner, and that the free end of the motor shaft is mounted by means of a bearing in a bearing seat (25) of the housing (10). 9. Electromotor adjustment drive according to claim 8, characterized in that a threaded bore (25a) is provided in the housing in the correct position to the motor shaft, into which an adjustment screw contacting the motor shaft can be screwed. , 10. Electromotoric adjustment drive according to claim 1, characterized in that the housing (10) preferably has on the side opposite the motor mounting ring (11) and parallel and at a distance from the spindle two parallel and spaced-apart and undercut grooves (16, 17) which can be gripped behind by webs of a control unit which can be fixed to the housing (10). " . Dewert 11. Electromotive adjustment drive according to claim 1, characterized in that the housing (10) contains at least one bearing chamber (26) ⁱⁿ the form of a bore, which is provided with grooves (27, 28, 29) running from the inside to the outside and extending in the longitudinal direction, the arrangement and number of which corresponds to the arrangement and number of outer webs of the spindle nut (30). _ ' · - 12. Electromotive adjustment drive according to claim 1, characterized in that the gear or worm wheel placed on the spindle has a corresponding internal thread for transmitting tensile or compressive forces. 13. Electromotive adjustment drive according to claim 12, characterized in that the spindle (12) has a slot running in the axial direction in the outer peripheral region, into which a locking pin (39) engages. 14. Electromotive adjustment drive according to claim 12, characterized in that the gear or worm wheel (24) is provided with a collar which has a bore or an elongated hole into which a welding bolt (40) fixed to the spindle (12) engages. 15. Electromotive adjustment drive according to one or more of the preceding claims; characterized in that a guide and sealing cap (37) for the lifting tube (35) is inserted into the free end of the flange tube (18). ■ : .. 35 3 !> &Iacgr; ■> . 1 ~> &Iacgr;&Zgr; -> 3 I ■) 1 1 "> 3 ^ 3 3 ? 3 I " Dewert 16. Electromotive adjustment drive according to one or more of the preceding claims, characterized in that an adapter can be plugged onto the profiled flange tube (18) in different angular positions. 17. Electromotive adjustment drive according to one or more of the preceding claims, characterized in that the control unit is equipped with at least two batteries or accumulators for the purpose of emergency lowering. 18. Electromotive adjustment drive according to one or more of the preceding claims, characterized in that the lifting tube (35) is provided with several circumferential beads (35a) which engage in corresponding grooves of a pin of the fork head (36) inserted into the lifting tube for positive fixing. 19. Electromotive adjustment drive according to one or more of the preceding claims, characterized in that the gear is a self-locking or a non-self-locking worm gear, in the case of a self-locking worm gear the diameter of the worm is larger than in the case of a non-self-locking worm gear, and in that the center distance is identical for both worm gears.