Door closer with free-swing function

Abstract

Door closer (11) with free-swing function (13) for a door, in particular for a fire door, which door has a door frame and a door leaf movable between a closed position and an open position, with an output shaft (15) rotatable about an axis of rotation a linkage (17) designed to couple the output shaft (15) to the door leaf when the door closer (11) is mounted on the door frame, or to couple the output shaft (15) to the door frame when the door closer (11) is mounted on the door leaf, a closing spring which is tensioned via the output shaft (15) when the door leaf is opened, and an electrically operated locking device (21) designed to lock the tensioned closing spring in the open position of the door leaf, so that the door leaf can be moved freely in the opening and closing direction without the influence of the spring force of the closing spring, a locking lever (19) designed separately from the linkage (17), which is non-rotatably connected to the output shaft (15) and assumes a locking position in the open position of the door leaf, in which the locking lever (19) is held by the locking device (21) when the locking device (21) is actuated, in order to lock the output shaft (15) and, via the output shaft (15), the tensioned closing spring, characterized in that the rotationally fixed connection of the locking lever (19) with the output shaft (15) is designed to be releasable and restorable, so that the rotational position of the locking lever (19) relative to the output shaft (15) is adjustable, thereby allowing the opening position of the door leaf to be adjusted.

Description

[0001] The invention relates to a door closer with a free-swing function for a door, in particular for a fire door, which door has a door frame and a door leaf movable between a closed position and an open position, with an output shaft rotatable about a pivot axis, a linkage provided for coupling the output shaft to the door leaf when the door closer is mounted on the door frame, or for coupling the output shaft to the door frame when the door closer is mounted on the door leaf, a closer spring which is tensioned via the output shaft during an opening movement of the door leaf, and an electrically actuated locking device which is designed to lock the tensioned closer spring in the open position of the door leaf, so that the door leaf can be moved freely in the opening and closing directions without the influence of the spring force of the closer spring, according to the preamble of claim 1.

[0002] A door closer of the type mentioned above is known from document DE 198 40 766 A1.

[0003] Door closers with a spring mechanism designed to automatically close an open door often pose a problem for people with physical limitations, the elderly, or the young, as the force required to open the door against the spring makes it difficult. However, door closers are essential for ensuring reliable door closure and thus safeguarding critical fire compartments. Door closers with a so-called free-swing function solve this problem by pre-tensioning the spring once and holding it in that tensioned position. Afterward, the door can be opened and closed with minimal resistance. The spring is only released to close the door securely, for example, in the event of a fire or during maintenance work.

[0004] The closing spring is typically held hydraulically by an electrically controlled check valve located inside the door closer. When the valve is closed, this valve interrupts the hydraulic circuit. However, such check valves have a very complex design and are therefore prone to failure and expensive. Furthermore, it has proven problematic that small residual amounts of hydraulic fluid can pass through even when the valve is closed, causing the closing spring to gradually and undesirably relax after being tensioned (leakage). To prevent this, expensive hydraulic seals must be used.

[0005] The door closer described in the aforementioned document has a housing in which a closer shaft is rotatably mounted. A sliding arm of the door closer is mounted on the closer shaft, and at its free end, this sliding arm has a slider that is slidably and rotatably guided in a guide rail. The sliding arm is freely rotatable on the closer shaft, thus decoupling the closing action from the sliding arm linkage. The door closer also has a closing lever that is fixed to the closer shaft. The closing lever can be locked in place by an electromagnet attached to the door frame.

[0006] EP 1 473 431 A1 discloses a door closer with a spring-operated closing mechanism and a closing lever coupled to the closing mechanism, which, when used as intended, serves to transmit the closing force to the door. The door closer further comprises an electromagnet which, when energized, is able to hold the closing lever in a pre-tensioned open position relative to the closing mechanism by interacting with a retaining surface located on the closing lever. GB 2 501 235 A discloses a closer with a latching mechanism and a magnetic actuator, wherein the door closer has a housing containing a spring and damper assembly. This known door closer does not have a free-running function.

[0007] DE 10 2017 201 942 A1 discloses a system for locking and / or emergency opening of a wing of a door, window or the like, with a drive having at least one mechanical energy storage device which is charged by an opening movement of the wing and discharged by a closing movement of the wing, at least one electric motor whose motor shaft is in operative connection with the wing, and control and / or regulating electronics for controlling the electric motor.

[0008] The invention is based on the objective of creating a door closer with a free-running function that is cost-effective and reliable at the same time.

[0009] This problem is solved by a door closer with the features of claim 1, and in particular by a locking lever formed separately from the linkage, which is rotationally fixed to the output shaft and assumes a locking position in the open position of the door leaf. In this position, when the locking device is actuated, the locking lever is held by the locking device to lock the output shaft and, via the output shaft, the tensioned closing spring. Instead of holding the closing spring by means of a complex electro-hydraulic valve, as in conventional door closers with a freewheel function, the door closer according to the invention prevents the output shaft from rotating by the locking lever, which is held in the locking position by the locking device.Since the relaxation of the closing spring is accompanied by a rotation of the output shaft in the closing direction, which rotation is prevented by the locked locking lever, the locking spring is locked and cannot gradually relax. Thus, the invention provides a door closer which, due to its solution for locking the tensioned closing spring, enables reliable operation with a simple and therefore fault-resistant design, and is cost-effective.

[0010] Advantageous embodiments of the invention will become apparent from the dependent claims, the description and the figures.

[0011] The freewheel function can be configured between the output shaft and an end of the linkage connected to the output shaft, or it can be configured at the free end of the linkage opposite the end connected to the output shaft, with the end of the linkage connected to the output shaft being rotationally fixed to the output shaft. This allows for a wide range of applications, with the second alternative being particularly cost-effective. Generally, the linkage can be configured as a scissor linkage and / or as a sliding arm.

[0012] Advantageously, an intermediate piece, rotatable about the axis of rotation of the output shaft and, in particular, separately designed, is provided, which is rotationally fixed to the output shaft, with the locking lever being rotationally fixed to the intermediate piece at one end facing the output shaft. In principle, the intermediate piece serves to connect the locking lever to the output shaft. However, it is also possible for the locking lever to be directly and immediately connected to the output shaft without an intermediate piece.

[0013] Preferably, the intermediate piece is mounted onto an end section of the output shaft, wherein the end section is not rotationally symmetrical with respect to the axis of rotation of the output shaft, in particular hexagonal, and wherein the intermediate piece has a recess that receives the end section in a form-fitting manner. The end section can be designed as a separate component that is rotationally fixed to the output shaft. However, the end section can also be formed integrally from a segment of the output shaft.

[0014] This allows a simple, rotationally fixed connection between the locking lever and the output shaft to be achieved via the intermediate piece.

[0015] A further development provides that, in a freewheel function formed between the output shaft and an end of the linkage connected to the output shaft, the intermediate piece is designed as a drive element, in particular a drive disc. This allows the number of components required to implement the freewheel function to be reduced in a simple manner, thus lowering the costs of the door closer according to the invention.

[0016] Preferably, the drive element has a circular arc-shaped, in particular semicircular arc-shaped, recess, and a drive pin is formed at the end of the linkage connected to the output shaft. This drive pin engages in the recess, and during the opening movement of the door leaf, which tensions the closing spring, the drive pin carries the drive element along with it, thereby rotating the output shaft in such a way that the closing spring is tensioned. This further reduces the number of components required to implement the free-running function. The length of the circular arc defines an angle over which the free-running function operates when the closing spring is locked.

[0017] Alternatively, in the case of a freewheel function formed at a free end of the linkage opposite the end connected to the output shaft, the intermediate piece can be designed as a projection, particularly a disc-shaped one, provided at the end of the linkage connected to the output shaft. This projection is rotationally fixed to the end of the linkage connected to the output shaft, thus ensuring that the linkage is rotationally fixed to the output shaft.

[0018] The locking lever's rotationally fixed connection to the output shaft is designed to be detachable and re-engageable, allowing the locking lever's rotational position relative to the output shaft to be adjusted, thereby adjusting the door leaf's opening position. This enables easy adjustment of the door leaf's opening position, resulting in a wide range of applications for the door closer according to the invention. For example, an opening angle of 90° or 180° can be set, at whichever set opening angle the closer spring can be locked by the locking mechanism.

[0019] Furthermore, the door closer according to the invention can be designed such that the rotationally fixed attachment of the locking lever to the intermediate piece is formed by a positive and / or force-fit connection, in particular comprising a serrated toothing. This allows for a particularly secure and backlash-free attachment of the locking lever to the intermediate piece.

[0020] In particular, the locking lever can have a clamp at one end connected to the output shaft, which can be tightened, especially by means of a screw, and by means of which the locking lever is attached to the intermediate piece. This allows the rotational position of the locking lever relative to the output shaft to be adjusted quickly and easily.

[0021] Furthermore, the intermediate piece can have knurling and / or external teeth along its contact surface with the locking lever. This allows the locking lever to be attached to the intermediate piece easily, securely, and without play.

[0022] The locking lever can advantageously be manufactured as a stamped and bent part, particularly from steel. This allows the locking lever to be produced in a simple stamping process followed by forming, without complex manufacturing steps.

[0023] The door closer according to the invention can also be characterized in that the locking device comprises an electronic control unit and an electric holding magnet controllable by the electronic control unit, and that the locking lever, in particular at one end facing away from the output shaft, has a holding section, wherein in the locking position of the locking lever the locking lever rests against the holding magnet via the holding section, and wherein the electronic control unit is configured to energize the holding magnet, at least in the locking position of the locking lever, in order to hold the locking lever in the locking position. This allows the locking lever to be held in place easily, with the electronic control unit enabling simple and centralized control of the holding magnet. Instead of the holding magnet, other devices are also conceivable that are configured to hold the locking lever in the locking position.For example, releasable mechanical locking devices that engage behind the locking lever to hold it in place could be considered.

[0024] The holding section can also be equipped with an anchor plate, whereby the anchor plate rests against the holding magnet in the locking position of the locking lever. This allows the locking lever to be held particularly reliably by the holding magnet.

[0025] Preferably, the locking device is designed to release the locking mechanism of the tensioned closing spring upon receiving a trigger signal, particularly in the event of a fire or a power failure, and to release the tensioned closing spring to perform a closing movement of the door leaf. This ensures reliable closing of the door leaf.

[0026] In particular, the electronic control unit can be configured not to energize the holding magnet upon receiving the release signal. This enables simple and centralized control of the door closer according to the invention.

[0027] In a further development of the invention, a sensor, in particular a microswitch or a proximity sensor, is provided which is electrically connected to the electronic control unit. The sensor is configured to detect when the locking lever reaches a predetermined detection position, in particular the latching position, during the opening movement that tensions the closing spring. The electronic control unit is configured to energize the holding magnet upon successful detection. The detection position can be predetermined by exceeding a switching threshold of the sensor as soon as the locking lever reaches the detection position. The detection position can be predetermined by adjusting the switching threshold. This targeted energizing of the holding magnet reduces the energy consumption of the door closer according to the invention.

[0028] Furthermore, a cover can be arranged on the locking lever which, in the locked position of the locking lever, conceals the locking mechanism, in particular the electronic control unit and the holding magnet, and the holding section, in particular the armature plate. Thus, the locking mechanism and the holding section can be effectively protected against contamination.

[0029] Preferably, a housing is provided within which the closing spring and the output shaft are arranged, wherein the housing has an opening so that the output shaft is accessible from outside the housing, and wherein the locking lever is arranged outside the housing and is rotationally fixed to the output shaft. This makes the locking lever easily accessible for adjusting its rotational position relative to the output shaft.

[0030] Furthermore, the locking lever can include an angled section at one end facing away from the output shaft, in particular one that is fitted with the anchor plate. This allows the locking device to be easily integrated into the door closer, especially if the locking lever is located outside the housing.

[0031] Advantageously, the door closer has a closing piston coupled to the output shaft via a gearbox. This piston is slidably arranged between the output shaft and the closing spring. The gearbox converts a rotary movement of the output shaft into a linear movement of the closing piston and vice versa. A rotary movement of the output shaft corresponding to the opening movement of the door leaf moves the closing piston towards the closing spring to tension the spring, and / or a relaxation of the closing spring moves the closing piston towards the output shaft to drive the output shaft into a rotary movement that moves the door leaf in the closing direction. This allows for a simple coupling of the closing spring to the output shaft and describes a common design for door closers.

[0032] The invention is described below by way of example with reference to the figures. Elements with the same function and mode of operation are each provided with the same reference numerals in the figures. They show schematically Fig. 1 a detailed view of the in Fig. 6 door closer shown, corresponding to the closed position of the door leaf, Fig. 2 a detailed view of the in Fig. 6 door closer shown, corresponding to the opening position of the door leaf or the locking position of the locking lever, Fig. 3 a detailed view of the in Fig. 6 door closer shown, corresponding to a position of the door leaf between the closed position and the open position or the locking position of the locking lever, Fig. 4 a detailed view of the freewheel function of the in Fig. 6 door closers shown in a top view, Fig. 5 a detailed view of the locking mechanism of the in Fig. 6 door closers shown, Fig. 6 a first embodiment of a door closer according to the invention with free-running function, Fig. 7 a representation of the in Fig. 6 door closer shown before assembly with linkage and locking lever, Fig. 8 a detailed view of a second embodiment of a door closer according to the invention with an alternative free-running function before assembly with linkage and locking lever, Fig. 9 a detailed view of the in Fig. 10 door closers shown, corresponding to the closed position of the door leaf, and Fig. 10 a third embodiment of a door closer according to the invention with a cover corresponding to the closing position of the door leaf or the locking position of the locking lever.

[0033] Fig. Figure 6 shows a first embodiment of a door closer 11 according to the invention with a free-running function 13 for a door, which door comprises a door frame and a door leaf movable between a closed position and an open position. The door closer 11 has a drive (not shown) with an output shaft 15 (in Fig. 6 (not shown) coupled closing piston (not shown). The output shaft 15 is only present in the case of the door closer 11 according to Fig. 8 shown. Regarding the door closer 11 according to Fig. Although Figure 8 represents an alternative embodiment, the output shaft 15 functions analogously in all embodiments shown in the figures and is only not recognizable due to the chosen illustrations. The closing piston is slidably arranged between the output shaft 15 and a closing spring (not shown), with the transmission converting a rotary movement of the output shaft 15 into a linear movement of the closing piston and vice versa. A rotary movement of the output shaft 15 corresponding to the opening movement of the door leaf moves the closing piston towards the closing spring to tension the closing spring. Relaxing the closing spring moves the closing piston towards the output shaft 15 to drive the output shaft 15 into a rotary movement that moves the door leaf in the closing direction.This allows for simple coupling of the closer spring to the output shaft 15 and describes a conventional design for door closers. Furthermore, the door closer 11 according to the invention includes a linkage 17 by means of which the output shaft 15 can be coupled to the door leaf when the door closer is mounted on the door frame, or the output shaft 15 can be coupled to the door frame when the door closer 11 is mounted on the door leaf. Additionally, a locking lever 19 and a locking device 21 for holding the locking lever 19 are provided to lock the tensioned closer spring in the open position of the door leaf. Due to the free-running function of the door closer 11, the door leaf can then move freely in the opening and closing directions without the influence of the spring force of the closer spring.

[0034] The closing spring and the output shaft 15 are arranged within a housing 12 of the door closer 11, the housing 12 being analogous to Fig. 8 has an opening 12a so that the output shaft 15 is accessible from outside the housing 12. Both the locking lever 19 and the locking device 21 are arranged outside the housing 12.

[0035] The detailed view according to Fig. 1 of the in Fig. The position of the linkage 17 in the door closer 11 shown in Figure 6 corresponds to the closed position of the door leaf. The linkage 17 is shown partially transparent to allow the freewheel function 13 to be seen. In the first embodiment, this freewheel function is formed between the output shaft 15 and an end of the linkage 17 connected to the output shaft 15. The freewheel function 13 comprises an intermediate piece 23 designed as a drive disc 23a with a semicircular recess 25 and a drive pin 27 formed on the linkage 17 that engages in the recess 25 of the drive disc 23a. While the drive disc 23a is rotationally fixed to the output shaft 15, the linkage 17 is rotatably mounted on the output shaft 15 by means of a first screw 29.Thus, with the drive disc 23a held in place, the linkage 17 can be moved freely relative to the output shaft 15 within the area of ​​the recess 25 of the drive disc 23a, i.e. over an angular range of 180°.

[0036] Furthermore, the drive disc 23a has a recess on its underside (not shown), which is shaped in the opposite direction to a hexagonal end section 31 of the output shaft 15, as shown in Fig. Figure 8 shows that the drive disc 23a is mounted onto the end section 31, which it positively engages in the recess. This ensures that the drive disc 23a is rotationally fixed to the output shaft 15. The end section 31 does not necessarily need to be fully engaged in the recess along its entire axial length.

[0037] The locking lever 19 is in turn fixedly attached to the drive plate 23a. For this purpose, the locking lever 19 has a clamp 35 at its end connected to the output shaft 15, which can be tightened by means of a second screw 33. Since the locking lever 19 is manufactured as a stamped and bent steel part, the clamp 35 can be easily produced by bending after stamping. Fig. Figure 4 shows the clamp 35 and the guide for the drive pin 27 in the recess 25 in more detail, whereby, for clarity, only the drive pin 27 and not the entire linkage 17 is shown. To achieve a higher frictional engagement between the clamp 35 and the drive disc 23a, the drive disc 23a has knurling 36 along its contact surface with the locking lever 19.

[0038] When assembling the door closer 11 according to Fig. 7. The driven plate 23a is placed onto the end section 31 of the output shaft 15 as described above, and the locking lever 19 is placed around the driven plate 23a with the clamp 35. By tightening the screw 33, the clamp 35 is secured around the driven plate 23a, preventing rotation. After attaching the linkage 17, the components are screwed to the output shaft 15 using the screw 29. Thus, the screw 29 primarily ensures the axial cohesion of the components and the rotatable bearing of the linkage 17, while the torsional rigidity of the screwed components is achieved through the respective interaction of the end section 31 of the output shaft 15 with the recess formed in the drive disc 23a, the clamp 35 of the locking lever 19 with the drive element 23a and the drive bolt 27 formed on the linkage 17 with the recess 25 of the drive disc 23a.

[0039] In Fig. Figure 2 shows a detailed view of the door closer 11 according to the open position of the door leaf. Starting from the closed position according to Fig. 1. When the door leaf is opened, the linkage 17 is rotated, which, via the drive pin 27 (which abuts at one end of the recess 25 in the direction of rotation), engages the drive disc 23a and thus rotates the output shaft 15. The rotation of the output shaft 15 tensions the closing spring until the door leaf is in the open position according to Fig. 2, in which the locking lever 19 rests against the locking device 21. In the detailed view of the locking device 21 according to Fig. Figure 5 shows that the locking device 21 comprises an electronic control unit 37 and an electric holding magnet 39. Accordingly, the locking lever 19 is provided at one end facing away from the output shaft 15 on an angled retaining section 40 with an armature plate 41, which also has a lug 43. In addition, a microswitch 45 is provided, which is electrically connected to the electronic control unit 37. The holding magnet 39, the armature plate 41 with the lug 43, and the microswitch 45 are arranged such that the armature plate 41 is in the open position according to Fig. 2 is located on the holding magnet 39 and thereby fully actuates the microswitch 45 via the nose 43.

[0040] When the microswitch 45 is sufficiently actuated, a switching threshold of the microswitch 45 is exceeded, causing the microswitch 45 to detect the locking lever 19 in a detection position. The height of the switching threshold can be adjusted so that the detection position corresponds precisely to the open position, meaning that full actuation of the microswitch 45 is required for detection. The electronic control unit 37 is further configured to energize the holding magnet 39 only when the locking lever 19 has been detected, thereby ultimately reducing the energy consumption of the door closer 11 according to the invention. Accordingly, in Fig. 2. The holding magnet 39 is energized, thereby holding the locking lever 19 via the armature plate 41. Since the locking lever 19 is fixedly attached to the drive disc 23a, which in turn is fixedly connected to the output shaft 15, the tensioned closing spring is also locked in the locking position via the output shaft 15.

[0041] In the locked position, the output shaft 15 cannot be rotated, while the door leaf, due to the free-running function 13, can move freely in the opening and closing directions without the influence of the spring force of the closer spring, as already mentioned above. As in Fig. As illustrated in Figure 3, by means of the linkage 17 being rotatably mounted on the output shaft 15, the door leaf can, in principle, be moved freely over the area in which the drive bolt 27 is guided in the recess 25, while the locking lever 19 is held in place.

[0042] If the electronic control unit 37 receives a trigger signal or the power supply fails, the holding magnet 39 is no longer energized. Consequently, the locking lever 19 is no longer held by the armature plate 41, and the locking mechanism of the closing spring is released. The closing spring can then relax, and the resulting spring force rotates the drive disc 23a in the closing direction via the output shaft 15. The drive disc 23a then strikes the drive bolt 27 and engages it, thereby rotating the linkage 17 and closing the door leaf automatically.

[0043] Due to the detachable, rotationally fixed mounting of the locking lever 19 on the drive disc 23a, the rotational position of the locking lever 19 relative to the output shaft 15 is adjustable. This allows the opening position of the door leaf to be easily adjusted, resulting in a wide range of applications for the door closer 11 according to the invention. For example, an opening angle of 90° or 180° or any other desired opening angle can be set, depending on which opening angle is required in the respective application.

[0044] In Fig. Figure 8 shows a second embodiment of a door closer 11 according to the invention with an alternative freewheel function 13 before the components are screwed together by means of the screw 29 towards the output shaft 15. In this embodiment, the freewheel function 13 is formed at a free end of the linkage 17, which is opposite the end of the linkage 17 connected to the output shaft 15 (not shown). The end of the linkage 17 connected to the output shaft 15 is rotationally fixed to the output shaft 15. For this purpose, the intermediate piece 23 is designed as an extension 23b, which has a recess (not shown) opposite to the hexagonal end section 31 of the output shaft 15, which positively engages the end section 31. The rotationally fixed connection between the extension 23b and the linkage 17 can be realized, for example, by welding or screwing.The diameter and knurling 36 of the extension 23b are identical to those of the drive disc 23a in the first embodiment, so that the same locking lever 19 is connected to the extension 23b in a rotationally fixed manner as described above. Otherwise, the door closer 11 of the second embodiment is essentially constructed the same as that of the first embodiment. Since, in the second embodiment, the linkage 17 is also fixed due to its rotationally fixed connection to the output shaft 15 when the closer spring is locked, the linkage 17 is not coupled to the door leaf, for example, by means of a sliding block and a guide rail (when the door closer 11 is mounted on the door frame), as this would also fix the door leaf. Instead, the door leaf can have a stop which, when the door leaf opens, merely abuts the linkage 17 and rotates it.In the open position, the closing spring can be locked by the locking lever 19 against the holding magnet 39, whereby the linkage 17, projecting into the room, is also fixed in this position. The door leaf can then be moved freely in the opening and closing directions without the influence of the closing spring's spring force. When the holding magnet 39 is released, the linkage 17 is rotated in the closing direction by the spring force of the closing spring. In this process, the linkage 17 abuts the stop of the door leaf in its respective position and pushes the door leaf into the closed position.

[0045] At the in Fig. Figure 9 shows a detailed view of a third embodiment of a door closer 11 according to the invention, which is essentially the same as the first embodiment. An additional cover 47 is provided, which is arranged on the locking lever 19 and conceals the anchor plate 41. In the locking position according to Fig.10 The cover 47 additionally conceals the holding magnet 39 and the electronic control unit 37. This protects the holding magnet 39 and the armature plate 41 from contamination, thus promoting reliable holding behavior in the long term. Reference symbol list 11 door closers 12 cases 12a Opening 13 Freewheel function 15 Output shaft 17 rods 19 locking levers 21 Locking device 23 Intermediate piece 23a Drive plate 23b Extension 25 recess 27 drive bolts 29 first screw 31 Final section 33 second screw 35 bell 36 knurling 37 electronic control unit 39 Holding magnet 40 Stop section 41 Anchor plate 43 Nose 45 microswitches 47 Cover

Claims

[1] Door closer (11) with free-running function (13) for a door, in particular for a fire door, which door has a door frame and a door leaf movable between a closed position and an open position, with an output shaft (15) rotatable about an axis of rotation a linkage (17) designed to couple the output shaft (15) to the door leaf when the door closer (11) is mounted on the door frame, or to couple the output shaft (15) to the door frame when the door closer (11) is mounted on the door leaf, a closing spring which is tensioned via the output shaft (15) when the door leaf is opened, and an electrically operated locking device (21) designed to lock the tensioned closing spring in the open position of the door leaf, so that the door leaf can be moved freely in the opening and closing direction without the influence of the spring force of the closing spring, a locking lever (19) designed separately from the linkage (17), which is non-rotatably connected to the output shaft (15) and assumes a locking position in the open position of the door leaf, in which the locking lever (19) is held by the locking device (21) when the locking device (21) is actuated, in order to lock the output shaft (15) and, via the output shaft (15), the tensioned closing spring, characterized by , that the rotationally fixed connection of the locking lever (19) with the output shaft (15) is designed to be releasable and restorable, so that the rotational position of the locking lever (19) relative to the output shaft (15) is adjustable, thereby allowing the opening position of the door leaf to be adjusted. [2] Door closer (11) according to claim 1, characterized by , that the freewheel function (13) is formed between the output shaft (15) and an end of the linkage (17) connected to the output shaft (15), or that the freewheel function (13) is formed at a free end of the linkage (17) opposite an end of the linkage (17) connected to the output shaft (15), wherein the end of the linkage (17) connected to the output shaft (15) is non-rotatably connected to the output shaft (15). [3] Door closer (11) according to any of the preceding claims, characterized by , that an intermediate piece (23) rotatable about the axis of rotation of the output shaft (15), in particular a separately designed, is provided, which is connected to the output shaft (15) in a rotationally fixed manner, wherein the locking lever (19) is attached to the intermediate piece (23) in a rotationally fixed manner with one end facing the output shaft (15). [4] Door closer (11) according to claim 3, characterized by, that the intermediate piece (23) is mounted on an end section (31) of the output shaft (15), wherein the end section (31) is not rotationally symmetrical with respect to the axis of rotation of the output shaft (15), in particular hexagonal, and wherein the intermediate piece (23) has a recess which receives the end section (31) in a form-fitting manner. [5] Door closer (11) according to claim 3 or 4, characterized by , that in a freewheel function (13) formed between the output shaft (15) and an end of the linkage (17) connected to the output shaft (15), the intermediate piece (23) is designed as a drive element (23a), in particular a drive disc. [6] Door closer (11) according to claim 5, characterized by, that the follower element (23a) has a circular arc-shaped, in particular semicircular arc-shaped, recess (25) and a follower bolt (27) is formed at the end of the linkage (17) connected to the output shaft (15), which engages in the recess (25), wherein during the opening movement of the door leaf which tensions the closing spring, the follower bolt (27) carries the follower element (23a) along and the output shaft (15) is thereby rotated in such a way that the closing spring is tensioned. [7] Door closer (11) according to claim 3 or 4, characterized by , that in the case of a freewheel function (13) formed at a free end of the linkage (17) opposite an end of the linkage (17) connected to the output shaft (15), the intermediate piece (23) is designed as a, in particular disc-shaped, extension (23b) provided at the end of the linkage (17) connected to the output shaft (15). [8] Door closer (11) according to one of claims 3 to 7, characterized by , that the rotationally fixed attachment of the locking lever (19) to the intermediate piece (23) is designed to be form-fit and / or force-fit, in particular comprising a serrated toothing. [9] Door closer (11) according to any one of claims 3 to 8, characterized by , that the locking lever (19) has at one end connected to the output shaft (15) a clamp (35) which can be tightened in particular by means of a screw (33) and by means of which the locking lever (19) is attached to the intermediate piece (23). [10] Door closer (11) according to any one of claims 3 to 9, characterized by that the intermediate piece (23) has knurling (36) and / or external teeth along its contact surface with the locking lever (19). [11] Door closer (11) according to any one of the preceding claims, characterized by , that the locking lever (19) is manufactured as a stamped and bent part, in particular from steel. [12] Door closer (11) according to any of the preceding claims, characterized by , that the locking device (21) comprises an electronic control unit (37) and an electric holding magnet (39) controllable by the electronic control unit (37), and that the locking lever (19), in particular at one end facing away from the output shaft (15), has a holding section (40), wherein in the locking position of the locking lever (19) the locking lever (19) rests against the holding magnet (39) via the holding section (40), and wherein the electronic control unit (37) is configured to energize the holding magnet (39) at least in the locking position of the locking lever (19) in order to hold the locking lever (19) in the locking position. [13] Door closer (11) according to claim 12, characterized by , that the holding section (40) is provided with an anchor plate (41), wherein in the locking position of the locking lever (19) the anchor plate (41) rests against the holding magnet (39). [14] Door closer (11) according to any of the preceding claims, characterized by , that the locking device (21) is designed to release the locking of the tensioned closing spring upon receipt of a release signal, in particular in the event of a fire or a power failure, and to release the tensioned closing spring to perform a closing movement of the door leaf. [15] Door closer (11) according to claim 14 and claim 12 or 13, characterized by , that the electronic control device (37) is designed not to energize the holding magnet (39) when the release signal is received. [16] Door closer (11) according to one of claims 12 to 15, characterized by, that a sensor (45), in particular a microswitch or a proximity sensor, is provided which is electrically connected to the electronic control unit (37), wherein the sensor (45) is configured to detect when the locking lever (19) reaches a predetermined detection position, in particular the locking position, during the opening movement which tensions the closing spring, and wherein the electronic control unit (37) is configured to energize the holding magnet (39) upon successful detection. [17] Door closer (11) according to claim 13, characterized by , that a cover is arranged on the locking lever (19) which, in the locking position of the locking lever (19), conceals the locking device (21), in particular the electronic control device (37) and the holding magnet (39), and the holding section (40), in particular the armature plate (41).

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