EP2653641B1 - Chain drive - Google Patents

Description

The present invention relates to a chain drive for moving a closure element of a building opening with the features of the preamble of claim 1.

Such closure elements of building openings, which moves closure elements by such a chain drive, in particular can be pivoted, are in particular windows, skylights, doors and smoke control and / or ventilation flaps, but without this listing is a final.

Chain drives for automatic and remote moving closure elements of building openings have long been known and used many times. They are particularly useful in the field of such building openings, the closure elements are not readily accessible, eg located at high altitude windows in stairwells, in roof installation situations or the like. But they are also used where a central control of the opening and closing of building openings desired and is provided, for example, to regulate an indoor climate about it. Furthermore, corresponding chain drives in smoke and heat exhaust systems (so-called RWA systems)

integrated. In the context of such facilities, certain building openings are intended to dissipate the resulting smoke and heat generated by the fire outside the building in case of fire. Automatic RWA systems typically have manual releases and smoke sensors or other sensors that detect a fire and send a corresponding signal to a central hotline. If a signal arrives there for a fire, then the corresponding chain drive or the chain drives are controlled to open corresponding smoke control flaps by means of a central control of the RWA system. There are relevant regulations for the required opening width as well as the opening speed, i. the time within which the required opening width must be reached.

The today common chain drives in common is that they have a typically elongated housing in which in addition to a drive unit, typically formed by a combination of a drive motor with a reduction gear, a power transmission chain is housed in a chain yard. The power transmission chain is displaced in its longitudinal direction by means of a chain wheel also arranged in the housing, so that it can be led out and issued from a passage opening arranged in the housing wall. The power transmission chain of such chain drives is one which has lugs connected by bolts while leaving a gap transverse to a longitudinal extent of the power transmission chain. There are such chain drives with power transmission chains in the form of simple chains, with fixed bolts, possibly guided over the bolt, solid sleeves, and those with so-called roller chains as power transmission chains, where on the bolt (or the sleeves) additional to the longitudinal axes of the Bolt rotatable rollers are applied. The power transmission chains known chain drives are typically back stiff, ie they can only roll in one direction. This is achieved by appropriate shaping of the tabs.

In most known chain drives of the chain station is divided into two sections, which are superimposed and extending in a longitudinal direction of the housing parallel to this. The power transmission chain is once deflected by 180 ° and is in fully retracted position so in the two superimposed sections. Thus, the chain station is about half as long as the total length of the power transmission chain. Accordingly, the housing of known chain drives are elongated. Their length dimension is essentially determined by the length of the force transmission chain to be accommodated in the retracted state in the chain station.

Particularly when used in SHE systems in which a comparatively large opening width of corresponding smoke control flaps or corresponding air flaps or a building opening intended for the smoke removal case occlusive windows or skylights must be particularly large, resulting in correspondingly large lengths to be selected of the power transmission chains. In a known from the prior art dual deflection of the power transmission chains in the chain of the housing of the chain drive this inevitably leads to a particularly long extension of the housing. On the other hand, often due to the structural conditions, e.g. by the distances of roof beams, between which the smoke control flaps or windows or skylights are provided for the smoke outlet in a RWA system building opening, a corresponding installation space or a possible installation length for a chain drive limited. It is important to keep the length of the housing of a corresponding chain drive short by appropriate design measures and still be able to accommodate a power transmission chain of the required length in the chain station of the housing can.

Here, in general, offers a solution, as in the DE 93 21 472 U1 is disclosed. There, a chain drive with the features of the preamble of claim 1 is disclosed. In contrast to other known solutions of the prior art, this chain drive has a chain railway station in which the power transmission chain is not stored in two mutually parallel sections, but in three such sections. For this purpose, the Power transmission chain in the warehouses at two opposite ends of the warehouses arranged reversing sections twice deflected by 180 °, so that they are in the fully retracted state in two outer sections, which are arranged close to each of two opposite side walls of the housing, and a middle Section, which is located between the outer sections, is divided.

At the time of the DE 39 21 472 U1 Although known solution compared to a chain drive with only simple deflection of the power transmission chain (ie storage in two receiving sections) significantly shortened design of the drive housing is achieved. However, this is in the example shown in this document very clearly at the expense of the height or depth of the chain drive, so the distance between the bottom and the top wall of the housing measured over the superimposed receiving portions of the chain station. This is due in particular to the fact that the deflection sections are designed with comparatively large radii. The design with large radii is required in the chain drive shown in this document in order to achieve a good and secure guidance of the power transmission chain both when entering and during the same. For this purpose, the receiving sections for the chain station are formed as separate tubular receptacles, without the individual receiving sections with their extending in the longitudinal direction, lying substantially parallel to the side walls of the housing separations approximately adjacent to each other. These generous radii were required, in particular, to transfer the force transmission chain during extension safely from one receiving section to the other, in particular from the third receiving section to the second receiving section, where the deflection radius is the narrower.

Alternatively, for example, from the DE 602 20 477 T2 Solutions with a subdivided in three sections arranged storage of the power transmission chain in a chain station, in which when retracting the power transmission chain in the chain station folding the chain and simultaneous filling or emptying of the second and third receiving portion he follows. These constructions allow a narrower design of the chain drive with significantly shorter distances from bottom to top wall of the housing, but are complex in the mechanics to design and prone to failure, since there is always a transverse guide an inner, second, the first chain end in the longitudinal direction of the power transmission chain opposite chain end directly to the start of retraction from the second to get to the third receiving section. This can cause malfunctions.

To remedy this situation and to provide a chain drive with compared to the last outlined chain drives simpler mechanical structure, which nevertheless allows a narrower compared to the first shown chain drive design is the object of the present invention.

This object is achieved by a chain drive with the features of the protection claim 1, advantageous developments are given in the dependent protection claims 2 to 7.

• ein in einer Längsrichtung langgestrecktes Gehäuse mit je zwei Seiten- und Stirnwänden sowie einer Boden- und einer Deckenwand,
• eine rückensteife Kraftübertragungskette, die über Bolzen verbundene, unter Belassung eines Zwischenraumes quer zu einer Längserstreckung der Kraftübertragungskette beabstandete Laschen aufweist,
• ein in dem Gehäuse angeordnetes Antriebsaggregat, welches insbesondere ein Antriebsmotor zusammen mit einem Untersetzungsgetriebe sein kann,
• ein von dem Antriebsmotor antreibbares und mit der Kraftübertragungskette zu deren Längsverlagerung zusammenwirkendes Kettenrad,
• eine die Gehäusewand durchbrechende Austrittsöffnung für die Kraftübertragungskette, aus der ein erstes, äußeres Kettenende der Kraftübertragungskette vorsteht,
• einen in dem Gehäuse vorgesehenen Kettenbahnhof zum Aufnehmen der Kraftübertragungskette in einem eingefahrenen Zustand in drei quer zu der Längsrichtung im Wesentlichen parallel zueinander in Richtung von einer zu der anderen Seitenwand gesehen übereinander geschichtet liegenden, jeweils im Wesentlichen parallel zu der Längsrichtung verlaufenden Aufnahmeabschnitten, die sich unterteilen in einen ersten, der Austrittsöffnung nächstgelegenen Aufnahmeabschnitt, der ein zu einer der Seitenwände hin gelegener äußerer Aufnahmeabschnitt ist, einen zweiten Aufnahmeabschnitt, der dem ersten Aufnahmeabschnitt gegenüberliegt und ein zur zweiten Seitenwand hin gelegener äußerer Aufnahmeabschnitt ist, und einen dritten Aufnahmeabschnitt, der ein zwischen dem ersten und dem zweiten Aufnahmeabschnitt liegender mittlerer Aufnahmeabschnitt ist, wobei an einer ersten Stirnseite des Kettenbahnhofs ein erster Umlenkabschnitt zum Überführen der Kraftübertragungskette zwischen dem ersten und dem zweiten Aufnahmeabschnitt unter Umlenkung derselben um im Wesentlichen 180° und an einer zweiten, der ersten Stirnseite gegenüberliegenden Stirnseite des Kettenbahnhofes ein zweiter Umlenkabschnitt zum Überführen der Kraftübertragungskette zwischen dem zweiten und dem dritten Aufnahmeabschnitt unter Umlenkung derselben um im Wesentlichen 180° vorgesehen sind.

According to the invention, a chain drive for moving a closure element of a building opening, in particular a window, a light dome, a door or a smoke extraction and / or ventilation flap has the following components:

• a longitudinally elongated housing with two side and end walls and a bottom and a top wall,
• a back stiff force transmission chain having lugs connected by bolts and spaced apart leaving a gap transverse to a longitudinal extent of the power transmission chain,
• a drive unit arranged in the housing, which in particular may be a drive motor together with a reduction gear,
• a sprocket drivable by the drive motor and cooperating with the power transmission chain for longitudinal displacement thereof;
• a housing wall opening through the force transmission chain, from which protrudes a first, outer chain end of the power transmission chain,
• a chain rack provided in the housing for receiving the power transmission chain in a retracted state in three transverse to the longitudinal direction substantially parallel to each other in the direction of a stacked to the other side wall, each lying substantially parallel to the longitudinal direction extending receiving portions which divide in a first receiving portion closest to the discharge port, which is an outer receiving portion located toward one of the side walls, a second receiving portion facing the first receiving portion and an outer receiving portion located toward the second side wall, and a third receiving portion interposed between the first receiving portion first and the second receiving portion lying central receiving portion, wherein at a first end face of the chain station, a first deflection portion for transferring the power transmission chain between the first and un d the second receiving portion under deflection thereof by substantially 180 ° and at a second, opposite the first end face of the chain station, a second deflection for transferring the power transmission chain between the second and the third receiving portion while deflecting the same by substantially 180 ° are provided.

• Der zweite und der dritte Aufnahmeabschnitt des Kettenbahnhofes sind durch eine quer zu den Seitenwänden des Gehäuses und quer zu der Längsrichtung der Kette in das Gehäuseinnere ragende blechartig dünnwandige Wandstruktur, die sich über einen Aufnahmeabschnitt in Längsrichtung des Gehäuses erstreckt, getrennt. Dabei schließen sich der zweite und der dritte Aufnahmeabschnitt des Kettenbahnhofes unmittelbar an die jeweils dieser zugewandte Seite der blechartigen Wandstruktur an. Ferner liegt eine frei stehende Kante der Wandstruktur in dem Bereich des zweiten Umlenkabschnittes und führt dort bei einer Überführung und Umlenkung der Kraftübertragungskette aus dem dritten Aufnahmeabschnitt in den zweiten Aufnahmeabschnitt die Laschen der Kraftübertragungskette auf ihrer dem Kettenrücken gegenüberliegenden Seite.

According to the invention, this chain drive has the following features:

• The second and the third receiving portion of the chain station are separated by a transversely to the side walls of the housing and transverse to the longitudinal direction of the chain into the housing interior projecting sheet-thin wall structure extending over a receiving portion in the longitudinal direction of the housing. In this case, the second and the third receiving section of the chain station close directly to each of these facing side of the sheet-like Wall structure on. Furthermore, a free-standing edge of the wall structure in the region of the second deflection section and there leads at a transfer and deflection of the power transmission chain from the third receiving portion in the second receiving portion, the tabs of the power transmission chain on its side opposite the chain back.

It has surprisingly been found that unlike a construction according to the DE 93 21 472 U1 provided and specified, when extending the power transmission chain no arcuate predetermined radius for the guide is required, but rather that the individual chain links for the deflection by substantially 180 ° equally drawn over the exposed edge of the sheet-like wall structure there and can be performed reliably. However, this circumstance necessitates that the force transmission chain in the region of the boundary formed between the second receiving section and the third receiving section by the sheet-like thin-walled wall structure can be mounted almost directly adjacent to one another, separated solely by the thin-walled sheet-like wall structure. It is not meant at the same time with a sheet-like material at the same time in the sense of metals or the like. The term "sheet-like" indicates only a ratio of the dimensions of this wall portion in the surface to its thickness, which is pronounced as in sheet metal components, be it metal or plastic or other material, strong in favor of surface area and at the expense of strength.

Thus can be achieved with the chain drive according to the invention, a substantially equally compact storage of the power transmission chain in the chain station, as they are known from DE 602 20 477 T2 is known, but without having to train for the complex mechanical design required there. Accordingly, the chain drive formed according to the invention of particular "slenderness" or "narrowness", ie be formed with a closely spaced distance between the walls bottom wall and ceiling wall of the housing.

A further advantage is obtained when the sheet-like thin-walled wall structure no the second receiving portion of the third receiving portion is completely separate wall, but rather a kind of openwork wall consisting of two of the two here referred to as floor and ceiling sides in the interior of the chain station projecting, aligned portions which form a longitudinal slot extending in the longitudinal direction of the housing between them. This construction not only saves material, it also creates a connection between the two receiving sections Nos. 2 and 3, so that there can take place a media exchange, for example, to reduce trapped moisture.

Furthermore, the separation between the first and third receiving portion is advantageously also formed by a sheet-like thin-walled wall structure, so that there is a particularly compact design of the chain drive, especially if the respective portions of the power transmission chain, if they rest in the receiving sections 1 and 3, only separated by the thin-walled wall structure.

With particular advantage, an end-side stop is provided in the region of the third receiving portion, which lies in the region of the first deflection section and on its outer side, with which it is separated from the deflection section and the first and the second receiving portion, a circular segment shape, which the the chain back opposite sides of the tabs of the power transmission chain leads, if this is transferred in the region of the first deflection section of the second receiving portion in the first receiving portion of the chain railway station.

In a transfer of the power transmission chain between the adjoining receiving sections no. 1 and 2 or no. 2 and 3 when retracting the chain this is in an arc on the previously described guide structures, ie in the second deflection especially the exposed edge of the first wall structure on a led the chain back leading outside opposite side arcuate portion formed. In particular, the chain is there but not or not exclusively performed on the tabs, but rather by projecting in the middle between the tabs webs on the bolts or roller chains on the bolt mounted roller sleeves attacks. Again, there is the advantage that tighter radii can be realized than would be possible with a guide only the tabs, which applies in particular in the region of the second deflection and is of importance. Because in a how to achieve with the invention narrow leadership of the power transmission chain in this area, in which the chain is hardly out in a bow, but rather is folded directly, the tabs do no longer arcuate movement. However, such a movement is still always described by the bolts or roller sleeves arranged thereon, which thus can still be guided safely in the manner described above, even in the case of a clearly drawn radius.

Advantageously, the housing of the chain drive according to the invention is made of metal. Such a metal housing is robust and, in particular, when the sheet-like thin-walled wall structure also consists of this material, a functionally functioning and low-wear function of the guide caused by the thin-walled wall structure with its exposed edge in the region of the second deflection section can function for a long period of time. In this case, the sheet-like thin-walled wall structure in the second deflection section, but also such a device for separating the first receiving portion of the second receiving portion, integrally formed with at least one side wall of the housing.

A magnetic extreme chain element at a second, opposite the first chain end in the longitudinal direction of the power transmission chain, inner chain end can nen in cooperation with an arranged near the sprocket magnetic sensor for a stroke limitation when extending the chain nen by the motor drive upon detection of the magnetic chain element is stopped by such a sensor.

Fig. 1

eine Ansicht eines erfindungsgemäßen Kettenantriebes von einer Seite her;

Fig. 2a

eine entlang der in Fig. 1 gezeigte Schnittlinie A-A genommene Schnittansicht des Kettenantriebes;

Fig. 2b

eine entlang der Schnittlinie B-B in Fig. 1 genommene Schnittansicht des Kettenantriebes;

Fig. 3

in drei Darstellungen a bis c in einer Schnittdarstellung und in vereinfachter und veranschaulichender Darstellung isoliert den Kettenbahnhof eines erfindungsgemäßen Kettenantriebes; und

Fig. 4

eine entlang der Schnittlinie A-A in Fig. 3c genommene Schnittdarstellung der Strukturen des Kettenbahnhofes gemäß Fig. 3.

Further advantages and features of a chain drive according to the invention will become apparent from the following description of an embodiment and further generalized embodiments thereof with reference to the accompanying figures. Showing:

Fig. 1

a view of a chain drive according to the invention from one side;

Fig. 2a

one along the in Fig. 1 sectional view AA taken sectional view of the chain drive;

Fig. 2b

one along the section line BB in Fig. 1 taken sectional view of the chain drive;

Fig. 3

in three illustrations a to c in a sectional view and in a simplified and illustrative representation isolated the chain station of a chain drive according to the invention; and

Fig. 4

one along the section line AA in Fig. 3c taken sectional view of the structures of the chain station according to Fig. 3 ,

In the figures, an exemplary embodiment of a possible implementation of a chain drive according to the invention is shown and will be described in more detail below. In the course of the description of the embodiment, also generalized explanations are given, which can be implemented detached from the concrete embodiment in general chain drives according to the invention with the features required by the invention, as far as can also form part of generally advantageous embodiments of a chain drive according to the invention without all concrete features of the embodiment.

In Fig. 1 is a view of the chain drive according to the invention 1 shown with a view of a side wall 4 of the housing 2 of the chain drive 1. The housing 2 has side walls 4 (only one to recognize here) two opposing end walls 3 and a bottom wall 5 and a top wall 6 ,

The arrangement in the interior of the housing 2 is from the two sectional views in Fig. 2a (Taken along the line AA in Fig. 1) and 2b (Section, taken along the line BB in Fig. 1 ) and recognize. The chain drive shown in this embodiment is centered with a constructed from one of the side walls 4 arranged chain outlet in the form of a passage opening 18 through the housing wall (end wall 4). Of course, other layers of the chain outlet can be selected from the housing 2, depending on how the chain drive according to the invention is to be used. A central outlet from the housing allows a central introduction of force into a moving building element, such as a window sash, even if the chain drive 1 is arranged symmetrically. However, for the actuation of the building element but at two different positions, such as two coupled to each other chain drives forces are introduced, an arrangement of the chain passage in the form of the passage opening 18 is displaced in the direction of one of the end walls 3 of advantage. A corresponding shift can be achieved by simply reshaping the arrangement of the drive unit described in more detail below.

In the in the Figures 1 to 2b shown chain drive 1, the interior of the housing 2 is roughly divided into two functional sections. Right of the chain passage, so the passage opening 18 in the FIGS. 2a 2b and 2b show a drive and control area in which the drive unit formed by a drive motor 7 and a cooperating with this reduction gear 8 and a non-illustrated and designated control for the drive motor 7 are arranged. On the left side is the chain unit with a chain station 16 for receiving a power transmission chain 10 in the retracted state, as in the FIGS. 2a and 2b is shown.

The drive unit consisting of the drive motor 7 and the reduction gear 8 drives a sprocket 9, with which the power transmission chain 10 can be moved. The power transmission chain 10 has at a first outer end 11, which protrudes through the passage opening 18 from the housing 2 of the chain drive 1, a connecting element 12 for connection to a corresponding counterpart on a moving building element, such as a window sash, a dome light, a ventilation flap or like.

The power transmission chain 10 is formed in a conventional manner from under load of a gap and distance parallel to each other arranged tabs 13, which are connected to each other via bolts 14. By appropriate choice of the tab shape and geometry, the power transmission chain 10 of the chain drive 1 shown is formed back stiff.

In the embodiment shown, the power transmission chain 10 is a roller chain, on the bolt 14, which connect the tabs 13 together, roller sleeves 15 are placed, which can rotate about a longitudinal axis of the bolt 14 around it.

As in particular in Fig. 2b can be seen well, the sprocket 9 engages in a conventional manner with its star-shaped extensions 19 between adjacent bolts 14 and on this patch roller sleeves 15 and so depending on the direction of rotation, the power transmission chain 10 extend through the passage opening 8 in the side wall 4 of the housing 2 or retract in another direction. For this purpose, the first outer end 11 opposite end of the power transmission chain 10 without fixing freely in the chain station 16 is movable. At this end, the power transmission chain 10 has an innermost chain link 17 which is magnetic. In a section just before the sprocket 9 in the direction of the force transmission chain 10 in the direction of the passage opening 18 is in the range of the chain path, a magnetic sensor (not shown), such as a Hall sensor or a reed switch, arranged, the presence of the innermost Registered chain link 17 in its sensor area and causes the control for the drive motor 7 to stop the latter. In this way, a complete extension of the power transmission chain 10 is prevented from the housing 2 out.

As in particular in Fig. 2a can be seen well, is in a retracted state, the power transmission chain 10 in the chain station 16 in three superposed receiving sections, a first in the direction of the power transmission chain 10 the sprocket 9 subsequent receiving portion 20, a second the first receiving portion 20 opposite, also to a side wall. 4 adjacent second receiving portion 21 and a arranged between the first receiving portion 20 and the second receiving portion 21 third, middle receiving portion 22 divided. In the region of the transition between the first receiving portion 20 and the second receiving portion 21 is a first deflection portion 23 in which the power transmission chain 10 is deflected by 180 °. A second deflection section 24, in which again a deflection of the force transmission chain 10 by 180 ° takes place, is located at the transition between the second receiving section 21 and the third, middle receiving section 22.

For the leadership of the power transmission chain 10 from the sprocket ago, ie from the direction of that portion of the power transmission chain 10 which faces in the first and in the second receiving portion 20 and 21 in the direction of the respective side wall 4, is a continuous web 25 between the tabs 13 and in the Area of the bolts 14 and the roller sleeves 15 arranged thereon, along which the bolts 14 or in this embodiment, the mounted thereon roller sleeves 15 when retracting the power transmission chain 10 are guided. In the areas of the deflection sections 23 and 24, this web 25 describes a circular arc, in the first deflection section with a comparatively large radius, in the second deflection section in a much smaller radius, which only slightly exceeds half the distance between two bolts 14.

Already in the Fig. 2a is clearly seen that the receiving portions are separated from each other by thin-walled wall portions, wherein a first thin-walled wall portion 26 separates the second receiving portion 21 from the third receiving portion 22, a second thin-walled wall portion 27 separates the third receiving portion 22 of the first receiving portion 20. It is also easy to see that the retracted force transmission chain 10 is tightly packed in the direction of the extension between the side walls 4, each only about the thickness of the thin-walled wall section 26 and 27 separated from each other. This allows a particularly compact construction of the chain drive 1 according to the invention.

The thin-walled wall sections 26 and 27 are again good in Fig. 4 It can also be seen here that in the region of the separation between the second receiving section 21 and the third receiving section 22, the thin-walled wall section 26 is composed of two from the bottom 5 and the top wall 6, respectively, into the interior of the chain railway station 16 in extending sections that are aligned with each other, but leave a gap 28 between them. Also visible are the structures of the guide of the power transmission chain to the bolt 14 and the roller sleeves 15 besorgenden web 25th

In the FIGS. 3a to c schematically a sectional view of the chain station 16 is shown. In this case, with three chain links and the last chain link shown by way of example, the course of motion of the power transmission chain 10 during the extension thereof in the second deflection section 24 is shown. It can now be seen that when extending an exposed edge 29 of the thin-walled wall portion 26, the tabs 13 is supported by the side opposite the sprocket side and leads when folding the power transmission chain 10 by 180 °. In this way, at this point, a particularly narrow radius of deflection of the power transmission chain 10 can be achieved, so that it is almost folded and lies on top of each other, separated only by the thickness of the thin-walled, sheet-like wall portion 26th

In addition, in the illustrations on the left the same section of the power transmission chain 10 shown again (without a representation of the movement) to show how in the further towards an end face 31 of the chain station 16 guided section beyond a stop 30 of the central receiving portion 22 a Circular arc descriptive guide structure for guiding the power transmission chain 10 is formed on their tabs or their bolts or rollers on the opposite side of the chain back to get in this way a guide of the power transmission chain 10 during extension thereof.

From the above description of an embodiment has once again become clear that with the inventive solution, in particular This consists in using a lying in the region of the second deflection portion 24 exposed edge of the thin-walled portion 26 as a guide structure for guiding the expiring force transmission chain 10 at the lugs of the opposite side of the chain fro ago, leading to a mechanically simple and solid solution, the Nevertheless, a very compact storage of the power transmission chain 10 in the chain station 16 allowed.

LIST OF REFERENCE NUMBERS

1

chain drive

2

casing

3

bulkhead

4

Side wall

5

bottom wall

6

ceiling wall

7

drive motor

8th

Reduction gear

9

Sprocket

10

Power transmission chain

11

first, outer end

12

connecting element

13

flap

14

bolt

15

roller sleeve

16

chain station

17

innermost chain link

18

Through opening

19

extension

20

receiving portion

21

receiving portion

22

receiving portion

23

deflecting

24

deflecting

25

web

26

thin-walled wall section

27

thin-walled wall section

28

gap

29

exposed edge

30

attack

31

front

32

magnetic innermost chain element

Claims (7)

1. A chain drive for moving a closure element of a building opening, especially a window, a skylight, a door or a smoke extraction flap and/or an aeration and/or venting flap, with

   a) a housing (2), elongated in a longitudinal direction respectively with two lateral (4) and front walls (3) as well as a bottom (5) and a ceiling wall (6),

   b) a power transmission chain (10) with a rigid back, a chain having spaced straps (13), connected by bolts (14), leaving an intermediate space transversale to a longitudinal extension of the power transmission chain (10),

   c) a drive unit (7, 8) arranged in the housing (2),

   d) a chain sprocket (9) which can be driven by a drive unit (7, 8) and co-operates with the power transmission chain (10) for the longitudinal transfer thereof,

   e) an exit opening (18) running through the housing wall for the power transmission chain (10), out of which protrudes a first outer chain end (11) of the power transmission chain (10),

   f) a chain station (16) provided in the housing (2), for receiving the power transmission chain (10) in a retracted state, in three receiving sections (20, 21, 22) transversal to the longitudinal direction, substantially parallel to each other in the direction from one lateral wall (4) to the other lateral wall (4) seen as piled up over one another, extending respectively parallel to the longitudinal direction, sections divided in a first receiving station (20) closest to the exit opening (18), a section which is an outer receiving section directed towards to a first of the lateral walls (4), a second receiving section (21), overlapping the first receiving section (20) and provides an outer receiving section directed towards the second lateral wall (4), and a third receiving section (22), which is a middle receiving section arranged between the first (20) receiving section and the second (21) receiving section, wherein a first diverting section (23) is provided at a first front side (31) of the chain station (16), for transferring the power transmission chain (10) between the first (20) receiving section and the second (21) receiving section by diverting the same by substantially 180° and, a second diverting section (24) for transferring the power transmission chain (10) is provided at a second front side, opposite the first front side (31) of the power transmission chain (16), between the second (21) receiving section and the third (22) receiving section by diverting the same by substantially 180°,

   characterised in that the second (21) receiving section and the third (22) receiving section of the chain station (16) are separated by a thin wall stucture (26) made of sheet-metal, protuding transversally to the bottom (5) or ceiling wall (6) of the housing (2) and transversally to the longitudinal direction of the power transmission chain (10) into the inside of the housing, a structure extending along at least one portion of the boundary between the second (21) receiving section and the third (22) receiving section in the longitudinal direction of the housing (2), wherein the second (21) receiving section and the third (22) receiving section of the chain station (16) are connected to each other immediately at the respective side of the sheet-metal wall structure (26) facing the same and wherein a free-standing edge (29) of the wall structure (16) is provided in the area of the second diverting section (24) and there guides the straps (23) of the power transmission chain (10) to its side opposite the back of the chain, when the power transmission chain (10) is transferred and diverted from the third receiving section (22) into the second receiving section (21).
2. A chain drive according to claim 1, characterised in that the sheet-metal thin wall structure (26) consists of two partial sections, aligned with and opposite to each other, transversal to the respective bottom (5) or ceiling wall (6), in particular perpendicular to said wall, said partial sections leaving between themselves a gap (28) extending in the longitudinal direction of the housing (2), wherein one of the straps (13) respectively bears against the free edge of the partial sections situated in the area of the second diverting section (24) and is guided from the third (22) receiving section into the second (21) receiving section in case of transfer of the power transmission chain (10).
3. A chain drive according to any of the preceding claims, characterised in that a second sheet-metal thin wall structure (27) is provided between the first receiving section (20) of the chain station (16) and the third receiving section (22) of the chain station (16), which wall structure is transveral to the bottom (5) and the front walls (3) of the housing (2) and transversal to the longitudinal direction of the power transmission chain (10) and protrudes into the inside of the housing, and which extends substantially over the length of said receiving sections (20, 22) and separates said receiving sections (20, 22) from each other.
4. A chain drive according to any of the preceding claims, characterised by a front-sided stop (30) of the third receiving section of the chain station (16), which stop (30) is provided in the area of the first diverting section (23), wherein an outer contour of the stop (30), pointing to the first diverting section, exhibits a circular section shape and guides the sides (opposite the back of the chain) of the straps (13) of the power transmission chain (10) and/or the bolts (14) or the rollers (15) provided thereon, when the same is transferred in the area of the first diverting section (23) from the second receiving section (21) into the first receiving section (20) of the chain station (16).
5. A chain drive according to any of the preceding claims, characterised by a housing (2) made of metal.
6. A chain drive according to any of the preceding claims, characterised in that the sheet-metal thin wall structure (26) is formed as a single piece with at least one of the walls, bottom wall (5) or ceiling wall (6) of the housing (2).
7. A chain drive according to any of the preceding claims, characterised by a magnetic innermost chain element (17) on a second, inner chain end, opposite the first chain end (11) in longitudinal direction of the power transmission chain (10).

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