Locking device

Abstract

The invention relates to a locking device (10) with a main lock (16), an additional lock (18), a drive rod (20), a further drive rod (44), locking elements (22), a motor drive unit (34) and with a compressible coupling element (48).The further drive rod (44) is arranged adjacent to the drive rod (20) and is coupled to the drive rod (20) via the coupling element (48) which is compressible along a drive rod longitudinal direction (12), wherein the coupling element (48) bears against the drive rod (20) at one end along the drive rod longitudinal direction (12) and bears against the further drive rod (44) at the other end, wherein the coupling element (48) can be compressed into a retracted position when a force is applied to the drive rod (20) opposite to the closing direction (SR) when the further drive rod (44) bears against the drive tappet (42) and the force exceeds a force threshold value, so that the drive rod (20) can be displaced relative to the further drive rod (44) in an opening direction (ÖR) opposite to the closing direction (SR), whereby the locking elements (22) can be brought into the unlocking position.

Description

[0001] The invention relates to a locking device for a door, a window or the like having features of the preamble of claim 1.

[0002] Such locking devices typically comprise a main lock and at least one additional lock, which are coupled by a drive rod. The locking elements of the main lock and the additional lock can be moved between a locked position and an unlocked position by driving the drive rod. A motorized drive unit, which drives the drive rod, allows the locking elements to be moved into the locked position.

[0003] Such a locking device is known, for example, from DE 20 2005 000 938 U1. This enables a door to be securely locked by engaging several locking elements in a door frame. However, in the event of disruptions, such as a power outage or failure of the motor drive unit, situations can arise in which the drive rod becomes blocked. If the locking elements are not in the unlocked position, the locking device cannot be released due to a self-locking mechanism in a gear of the drive unit. A door, window, or the like may then not be able to be opened.

[0004] Another locking device is known from EP 3 287 577 A1, wherein this locking device has a drive rod and a further drive rod which are coupled by means of a tension spring. Furthermore, a motor drive unit is provided which acts on the further drive rod. If the motor drive unit is inoperative (power failure or defect), the drive rod can be displaced relative to the drive rod by applying an appropriate actuating force by overcoming the spring force of the tension spring and tensioning the tension spring. This allows a door, window or the like to be opened even if the motor drive unit is inoperative. To actuate the drive rod, a minimum force must be applied, which may be so high that actuation of the drive rod, for example by means of a profile cylinder of the main lock of the locking device, is no longer possible.

[0005] The invention is based on the object of enabling a reliable release of a locking device with low actuating force using simple structural means.

[0006] The invention solves this problem by a locking device with the features of claim 1.

[0007] The locking device is designed and / or intended as a locking device for a door, a window or the like.

[0008] The locking device comprises a main lock and at least one additional lock. The main lock and the additional lock are gear-coupled by a (first) drive rod, and by driving the drive rod, locking elements, in particular locking elements, of the main lock and / or additional lock can be displaced between a locking position and an unlocking position.

[0009] The locking device also has a motor drive unit by means of which the drive rod can be driven in the closing direction, whereby the locking elements can be or are moved into the locking position.

[0010] To drive the drive rod in the closing direction, the drive unit acts on a further drive rod (second drive rod) by means of a drive tappet. The further drive rod is arranged adjacent to the (first) drive rod and is coupled to the drive rod via a coupling element that is compressible, in particular reversibly, along a drive rod longitudinal direction. The coupling element rests at one end against the (first) drive rod and at the other end against the further drive rod along the drive rod longitudinal direction.

[0011] When a force is applied to the drive rod in the opposite direction to the closing direction, when the further drive rod rests against the drive tappet and the (applied) force exceeds a force threshold value (required to compress the coupling element), the coupling element can be moved or compressed from an extended position (uncompressed state) into a retracted position (compressed state), so that the drive rod can be displaced relative to the further drive rod in an opening direction opposite to the closing direction, whereby the locking elements can be brought into the unlocking position.

[0012] The proposed locking device has the advantage that, if the motorized drive unit is inoperative (power failure or defect), the door, window, or similar device can be held in the closed position by means of the main lock, e.g., the main latch, and can be easily opened at any time in the event of a panic by applying force to the drive rod (compressing the coupling element). Furthermore, this design can prevent damage to the door frame if the door, window, or similar device is not (yet) in the closed position or if the locking device is incorrectly adjusted, e.g., relative to the frame, and the locking process (drive rod moves in the closing direction and locking elements are moved into the locked position) has already been initiated.

[0013] The proposed design represents an increase in security. Thus, when a force below the force threshold is applied, in particular to the additional drive rod, the drive rods are displaced together. A relative displacement of the (first) drive rod and the additional drive rod to one another does not occur or only occurs to a negligible extent. It is conceivable that the force threshold lies above an actuating force required to operate the locking device with a main lock and at least one additional lock. When an actuating force above the force threshold is applied to the (first) drive rod (coupling element is compressed), the drive rod can be displaced relative to the additional drive rod. A displacement occurs along the longitudinal direction of the drive rod.This allows a certain extent for the drive rod to be moved independently of the other drive rod, so that by moving the drive rod, the locking elements of the main lock and the secondary lock can be moved into the unlocking position and thus a door, a window or the like can be released, even in the case where the drive unit and / or the other drive rod are blocked or not working properly.

[0014] The (first) drive rod and the additional drive rod are arranged in the same orientation relative to each other (both aligned along the drive rod's longitudinal direction or the faceplate's longitudinal direction), preferably parallel to each other. Irrespective of this, the coupling element can be designed as a plastically or elastically deformable coupling member.

[0015] The drive plunger of the motorized drive unit is designed to be retractable and extendable relative to the drive unit housing. In the retracted position, the drive plunger protrudes only slightly from the drive unit housing. In the extended position, the drive plunger is fully extended from the drive unit housing.

[0016] The control operation of the motor drive unit preferably provides that the drive plunger for driving the (first) drive rod in the closing direction, starting from the retracted position, comes into contact with the other drive rod and moves the other drive rod into the extended position in the closing direction by extending the drive plunger. After reaching the maximum extended position of the drive plunger, it is preferably provided that the drive plunger returns to the retracted position.

[0017] In order to attach the coupling element to the drive rod or the further drive rod, one or more projections or one or more recesses can be formed on the drive rod and on the further drive rod.

[0018] The locking device can be designed, in particular, as a motor-driven multi-point locking system. The locking device is arranged, in particular, on a leaf of a door, window, or the like and secures it to a door frame or window frame. Locking elements, in particular locking elements, of the main lock and / or additional lock correspond to corresponding openings or counter-elements in the door frame or window frame and cooperate with them to lock the door leaf or window leaf.

[0019] An actuation of the (first) drive rod to move the locking elements, in particular into the unlocking position, can be carried out by a change function in the main lock (key operation of the main lock), an actuation of a handle follower of the main lock (panic release device) or by a further motor drive unit which moves the drive rod in such a way that the locking elements are moved into the unlocking position (movement of the drive rod in the opening direction).

[0020] In a preferred embodiment, the coupling element can be designed as a fluid damper with a cylinder, a piston which is guided displaceably in the cylinder and has a piston rod fastened to it and protruding from the cylinder. This contributes to a robust and reversible design of the coupling element. The fluid damper can be moved into a retracted position by applying a constant force, for example starting from an extended position. In addition, by appropriately designing the fluid damper on the locking device, a moderate force threshold value can be achieved which remains practically constant over the displacement path of the piston rod (difference between the retracted position and the extended position). This facilitates targeted adjustment of the force threshold value such that actuation of the drive rod if the drive unit or the actuator is not working properly.A blocked additional drive rod can be opened using both the follower and the profile cylinder of the main lock. The cylinder of the fluid damper can be located in a fluid damper housing or form a fluid damper housing.

[0021] Advantageously, the cylinder can be coupled to the additional drive rod in such a way that the cylinder is immovable relative to the additional drive rod along the drive rod's longitudinal direction. This contributes to a stable coupling between the additional drive rod and the cylinder and reduces play in the force flow between the drive unit and the (first) drive rod. For the (immovable) coupling of the cylinder and the additional drive rod, one or more projections or one or more recesses can be formed on the additional drive rod.

[0022] Specifically, a recess can be formed in the additional drive rod, into which the cylinder of the fluid damper protrudes and rests at each end (with its ends aligned along the longitudinal direction of the drive rod). This provides a structurally simple and space-efficient coupling of the cylinder and additional drive rod. The length of the recess preferably corresponds to the length of the cylinder of the fluid damper.

[0023] Advantageously, a further recess can be formed in the drive rod, wherein the fluid damper is arranged between the drive rod and the further drive rod, and the cylinder also extends into the further recess. In other words, the cylinder of the fluid damper extends both into the recess of the further drive rod and into the further recess of the (first) drive rod. This contributes to a compact design of the fluid damper and drive rods, in particular orthogonal to the drive rod longitudinal direction. The further recess preferably has a greater length along the drive rod longitudinal direction than the length of the cylinder of the fluid damper.The length of the additional recess along the longitudinal direction of the drive rod can, in particular, correspond to the length of the cylinder plus the length of the adjustment travel of the piston rod of the fluid damper (difference between the retracted and extended positions of the piston rod relative to the cylinder). This promotes a relative movement of the (first) drive rod relative to the fluid damper or its cylinder.

[0024] The fluid damper can be advantageously preloaded so that the piston rod is forced into its extended position relative to the cylinder and rests with its free end against an actuating section of the drive rod. This reduces play in the drive train between the motor drive unit and the (first) drive rod. The actuating section can be designed as a projection on the drive rod (an additional component attached to the drive rod or formed integrally with the drive rod). The fluid damper can be preloaded in the extension direction by a spring (the spring urges the piston rod into the extended position relative to the cylinder when unloaded).

[0025] In a preferred embodiment, the drive unit and the fluid damper can overlap along the longitudinal direction of the drive rod, with the drive unit being attached to a faceplate extending along the longitudinal direction of the drive rod by means of spacers. The drive rod, the fluid damper, and the additional drive rod are arranged in the space between the faceplate and the drive unit. The spacers create a free space between the motorized drive unit and the faceplate, in which the aforementioned components can be arranged.

[0026] Specifically, the additional drive rod can have an angled section at one end, and the drive plunger can act on the angled section to drive the drive rod in the closing direction. This involves a structurally simple coupling between the drive plunger and the additional drive rod. The angled section can, in particular, be angled at a right angle to the additional drive rod (longitudinal direction of the drive rod).

[0027] The main lock can conveniently have a follower, by means of which the drive rod can be driven, and / or a profile cylinder, by means of which the drive rod can be driven. These are proven and reliable actuation devices for the main lock. The main lock has a lock gear, which can be actuated via the follower and the profile cylinder (change function). The lock gear acts on the drive rod or sections of the drive rod, e.g., via one or more drive rod connecting slides.

[0028] In a preferred embodiment, the locking device can have a further drive unit by means of which the drive rod can be driven in the opening direction. This allows the locking elements to be moved into the unlocked position. The further drive unit can preferably act directly on the (first) drive rod. Specifically, the further drive unit can have a retractable and extendable drive plunger that acts on a further actuating section arranged on the (first) drive rod. The retractable and extendable drive plunger of the further drive unit can be designed analogously and / or function like the drive plunger of the (first) drive unit. The further actuating section can be designed as a projection on the drive rod (additional component attached to the drive rod or formed integrally with the drive rod).

[0029] Advantageously, the locking device can have a control unit with a query sensor. This allows for targeted control of the drive units. Diagnosis / query of the current position of the locking device is also possible. Furthermore, the locking device can be coupled to other components that actuate the locking device, e.g., an access control device, in particular a card reader, a fingerprint sensor, or the like.

[0030] Specifically, the locking elements can be designed as locking elements. Locking elements allow for particularly secure locking of a sash relative to a frame.

[0031] The locking elements can each be designed as an extendable bolt (e.g. along its longitudinal extent) or as a pivoting bolt.

[0032] In an alternative embodiment, the drive rod and the additional drive rod can each have a friction section or a friction element that are in contact with each other and form the coupling element. This contributes to a structurally simple and particularly space-saving design without additional components. Below the force threshold of a force applied to the drive rod or the additional drive rod, the drive rod and the additional drive rod are displaced together. If the applied force is above the force threshold, a displacement of the drive rod and the additional drive rod relative to each other is possible. In this process, the friction sections / friction elements run or slide against each other.

[0033] The invention is explained in more detail below with reference to the figures, in which identical or functionally equivalent elements are provided with identical reference numerals, if necessary, but only once. They show: Fig.1 shows an embodiment of a locking device in a side view; Fig.2 shows a part of the locking device in a perspective exploded view Fig.1 ; Fig.3a the locking device from Figure 1 with drive tappet in (still) retracted position, coupling element in extended position and locking elements in unlocking position, in a partially sectioned side view; Fig.3b the locking device from Figure 1 with drive plunger in (re)tracted position, coupling element in extended position and locking elements in locking position, in a partially sectioned side view; Fig.4a the locking device from Figure 1 with drive tappet in extended position (blocked), coupling element in extended position and locking elements in locking position, in a partially sectioned side view; and Fig.4b the locking device from Figure 1with drive plunger in extended position (blocked), coupling element in retracted position and locking elements in unlocked position, in a partially sectioned side view.

[0034] Figure 1 shows a locking device for a door, a window or the like, which is designated overall by the reference numeral 10.

[0035] The locking device 10 has a face plate 14 extending along a face plate or drive rod longitudinal direction 12, to which components of the locking device 10 are fastened and via which the locking device 10 can be fastened, for example, to a door or window sash (not shown).

[0036] The locking device 10 has a main lock 16 and at least one additional lock 18, in the example three additional locks 18. The main lock 16 and the additional locks 18 are coupled by means of a (first) drive rod 20.

[0037] The drive rod 20 can be interrupted at the main lock 16 and / or at one or more of the additional locks 18, so that the drive rod 20 is formed from several drive rod sections. The drive rod sections can be coupled by means of a slotted guide, by means of a coupling element penetrating the main lock 16 or an additional lock 18 in the longitudinal direction 12 of the drive rod, or by means of a respective lock gear.

[0038] The main lock 16 and the additional locks 18 each have locking elements 22. In the example, the locking elements 22 are designed as locking elements. The locking elements on the additional locks 18 are each designed as pivoting bolts 24. The locking element of the main lock 16 is designed as an extendable bolt or lock bolt 26.

[0039] The main lock 16 has a latch 28, which can also be referred to as the main latch 28. In the example, the main lock 16 further has a follower 30 and a profile cylinder 32, each of which is coupled to a lock gear of the main lock 16 (not shown), whereby the drive rod 20 can be driven.

[0040] By driving the drive rod 20, the locking elements of the main lock 16 and the additional locks 18 can be moved between a locking position and an unlocking position.

[0041] The locking device 10 has a motor drive unit 34, by means of which the drive rod 20 can be driven in the closing direction SR, whereby the locking elements can be displaced into the locking position.

[0042] The locking device 10 also has an additional motorized drive unit 36, by means of which the drive rod 20 can be driven in the opening direction ÖR. This allows the locking elements to be moved into the unlocked position. The additional motorized drive unit 36 ​​can be constructed analogously to the drive unit 34 and act directly on the drive rod 20, as explained above.

[0043] The locking device 10 has a control unit 38 with a query sensor.

[0044] The main lock 16, the additional locks 18, the motor drive units 34, 36 and the control unit 38 are each attached to the face plate 14, e.g. screwed.

[0045] Figure 2 shows in a perspective exploded view a part of the locking device 10 from Figure 1 .

[0046] The drive unit 34 has a drive plunger 42 that can be extended and retracted relative to the housing 40 of the drive unit 34. The drive unit 34 acts on a further drive rod 44 by means of the drive plunger 42 to drive the drive rod 20 in the closing direction SR. The further drive rod 44 is arranged adjacent to the (first) drive rod 20, in the example parallel to it, and has an angled section 46 at one end, on which the drive plunger 42 acts to drive the drive rod 20 in the closing direction SR.

[0047] The drive rod 20 and the further drive rod 44 are coupled to one another via a coupling element 48 that is compressible along a drive rod longitudinal direction 12. The coupling element 48 rests at one end against the drive rod 20 and at the other end against the further drive rod 44 along the drive rod longitudinal direction 12. The coupling element 48 can be moved or compressed from an extended position (uncompressed state) to a retracted position (compressed state), as explained further below.

[0048] In the example, the coupling element 48 is designed as a fluid damper 50 with a cylinder 52 and a piston (not shown) slidably guided in the cylinder with a piston rod 54 attached thereto and projecting from the cylinder 52.

[0049] In an embodiment not shown, the drive rod 20 and the further drive rod 44 can each have a friction section or a friction element which are in contact with one another and form the coupling element 48.

[0050] The cylinder 52 is coupled to the additional drive rod 44 in such a way that the cylinder 52 is immovable relative to the additional drive rod 44 along the drive rod's longitudinal direction 12. Specifically, a recess 56 is formed in the additional drive rod 44, into which the cylinder 52 of the fluid damper 50 projects and rests at each end, i.e., with its axial ends. In the example, the length of the recess 56 along or parallel to the drive rod's longitudinal direction 12 corresponds to the length of the cylinder 52 of the fluid damper 50.

[0051] A further recess 58 is formed in the drive rod 20, wherein the fluid damper 50 is arranged between the drive rod 20 and the further drive rod 44. The cylinder 52 of the fluid damper 50 projects into the recess 56 of the further drive rod 44 as well as into the further recess 58 of the drive rod 20 (cf., among others, Fig.3a ).

[0052] In the example, the further recess 58 has a greater length along the drive rod longitudinal direction 12 than the length of the cylinder 52 of the fluid damper 50. The length of the further recess 58 along the drive rod longitudinal direction 12 corresponds in particular to the length of the cylinder 52 plus the length of the adjustment path of the piston rod 54 of the fluid damper 50 (difference between the retracted position and the extended position of the piston rod 54 relative to the cylinder 52).

[0053] In the example, the fluid damper 50 is preloaded so that the piston rod 54 is forced into its extended position relative to the cylinder 52 and rests with its free end against an actuating portion 60 of the drive rod 20. The actuating portion 60 can be formed as a projection on the drive rod 20, as explained above.

[0054] The drive unit 34 and the fluid damper 50 overlap each other along the drive rod longitudinal direction 12, wherein the drive unit 34 is fastened to the face plate 14 by means of spacers 62, wherein the drive rod 20, the fluid damper 50 and the further drive rod 44 are arranged in the intermediate space 64 between the face plate 14 and the drive unit 34 (cf. Fig.2 and e.g. Fig.3a ).

[0055] The locking device 10 works as follows: Figure 3ashows a basic position of the locking device 10 with the drive plunger 42 in the (still) retracted position, the fluid damper 50 in the extended (uncompressed) position and the locking elements or pivot bolts 24 in the unlocking position (pivot bolt 24 pivoted in).

[0056] To lock the locking device 10, the (first) drive unit 34 moves the drive plunger 42 from the retracted position to the extended position, whereby the drive plunger 42 rests against the angled section 46 of the additional drive rod 44 and displaces the additional drive rod 44 in the closing direction (downward in the figures). After the drive plunger 42 has reached its extended position, the drive unit 34, if functioning properly, moves the drive plunger 42 back to its initial position (drive plunger 42 retracted; see Fig.3b ).

[0057] The additional drive unit 36 ​​can now, if necessary, actuate the drive rod 20 in the opening direction (upward in the figures) and retract or pivot the locking elements or pivot bolts 24 of the additional locks 18. This state can also be brought about by actuating the handle (actuating the follower 30) in the event of a panic or by the change function (key actuation of the main lock 16 via the profile cylinder 32).

[0058] However, should the drive unit 34 fail during the locking process and the drive plunger 42 remain in its extended position (cf. Fig.4a ), the locking device 10 would be blocked without the coupling element 48 between the drive rod 20 and the further drive rod 44. Unlocking the locking device 10 (retracting / pivoting the locking elements) would then not be possible.

[0059] By means of the coupling element 48, which in the example is designed as a fluid damper 50, the locking device 10 can be unlocked by applying a force exceeding a force threshold value to the drive rod 20 and the door or window can be opened.

[0060] For this purpose, the fluid damper 50 is moved from an extended position (uncompressed state; cf. Figure 4a ) into a retracted position (compressed state; see Figure 4b) compressible. The drive rod 20 can then be displaced relative to the further drive rod 44 in an opening direction ÖR opposite to the closing direction, whereby the locking elements or pivot bolts 24 can be brought into the unlocking position.

[0061] As already explained, a force can be applied to the drive rod 20 by actuating the follower 30 (panic case), by the change function (key actuation of the main lock 16 via the profile cylinder 32) or via the additional motor drive unit 36.

[0062] The advantage of the proposed design using a coupling element 48, in particular a fluid damper 50, is that as long as the motor drive unit 34 is out of operation (power failure or defect), the door or window is held in the closed position by the main latch 28 of the main lock 16 and can be easily opened at any time in the event of a panic. Coupling the drive rods 20, 44 using a coupling element 48 also prevents damage to the frame of the door or window if the locking process was initiated while the door or window sash was not closed or if the fittings were incorrectly adjusted.

Claims

1. Locking device (10) for a door, a window or the like, with a main lock (16) and at least one additional lock (18), wherein the main lock (16) and the additional lock (18) are coupled by means of a drive rod (20) and by driving the drive rod (20) locking elements (22) of the main lock (16) and / or additional lock (18) can be displaced between a locking position and an unlocking position, and with a motor drive unit (34) by means of which the drive rod (20) can be driven in the closing direction (SR), whereby the locking elements (22) can be displaced into the locking position, characterized in thatthe drive unit (34) for driving the drive rod (20) in the closing direction by means of a drive tappet (42) acts on a further drive rod (44), wherein the further drive rod (44) is arranged adjacent to the drive rod (20) and is coupled to the drive rod (20) via a coupling element (48) compressible along a drive rod longitudinal direction (12), wherein the coupling element (48) bears at one end against the drive rod (20) along the drive rod longitudinal direction (12) and at the other end against the further drive rod (44), wherein the coupling element (48) can be brought into a retracted position upon application of a force to the drive rod (20) counter to the closing direction (SR) when the further drive rod (44) bears against the drive tappet (42) and the force exceeds a force threshold value, so that the drive rod (20) relative to the further drive rod (44) is displaceable in an opening direction (ÖR) opposite to the closing direction (SR),whereby the locking elements (22) can be brought into the unlocking position., 2. Locking device (10) according to claim 1, characterized in that the coupling element (48) is designed as a fluid damper (50) with a cylinder (52), a piston displaceably guided in the cylinder (52) with a piston rod (54) attached to it and projecting from the cylinder (52).

3. Locking device (10) according to claim 2, characterized in that the cylinder (52) is coupled to the further drive rod (44) in such a way that the cylinder (52) is immovable along the drive rod longitudinal direction (12) relative to the further drive rod (44).

4. Locking device (10) according to claim 2 or 3, characterized in that a recess (56) is formed in the further drive rod (44), into which the cylinder (52) of the fluid damper (60) projects and rests at each end.

5. Locking device (10) according to claim 4, characterized in thata further recess (58) is formed in the drive rod (20), wherein the fluid damper (50) is arranged between the drive rod (20) and the further drive rod (44) and the cylinder (52) also projects into the further recess (58).

6. Locking device (10) according to one of claims 2 to 5, characterized in that the fluid damper (50) is prestressed so that the piston rod (54) is forced into its extended position relative to the cylinder (52) and rests with its free end on an actuating section (60) of the drive rod (20).

7. Locking device (10) according to one of claims 2 to 6, characterized in thatthe drive unit (34) and the fluid damper (50) overlap along the drive rod longitudinal direction (12), wherein the drive unit (34) is fastened by means of spacers (62) to a face plate (14) extending along the drive rod longitudinal direction (12), wherein the drive rod (20), the fluid damper (50) and the further drive rod (44) are arranged in the intermediate space (64) between the face plate (14) and the drive unit (34).

8. Locking device (10) according to one of the preceding claims, characterized in that the further drive rod (44) has an angled section (46) at one end and the drive tappet (42) acts on the angled section (46) to drive the drive rod (20) in the closing direction (SR).

9. Locking device (10) according to one of the preceding claims, characterized in thatthe main lock (16) has a follower (30) by means of which the drive rod (20) can be driven and / or that the main lock (16) has a profile cylinder (32) by means of which the drive rod (20) can be driven.

10. Locking device (10) according to one of the preceding claims, characterized in that the locking device (10) has a further motor drive unit (36) by means of which the drive rod (20) can be driven in the opening direction (ÖR).

11. Locking device (10) according to one of the preceding claims, characterized in that the locking device (10) has a control unit (38) with a query sensor.

12. Locking device (10) according to one of the preceding claims, characterized in that the locking elements (22) are designed as locking elements.

13. Locking device (10) according to claim 1, characterized in thatthe drive rod (20) and the further drive rod (44) each have a friction section or a friction element which are in contact with each other and form the coupling element (48).

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