Technical Field

The present disclosure generally relates to control of movements of access members, such as door leaves. In particular, an arrangement for controlling movements of an access member relative to a frame, an access member system comprising an arrangement, and a method of controlling movements of an access member relative to a frame, are provided.

Background

A door closer may be used to control closing of a door leaf in a controlled manner. When installing a door closer, it maybe desirable that a torque provided by the door closer and acting on a door leaf exhibits a certain torque profile with respect to an opening movement or a closing movement of the door leaf. For example, it maybe desirable that the door closer provides an increased torque during a last part of a closing movement to latch the door leaf. Regulations may also demand a certain behavior of the door closer, for example that the door leaf is not too heavy to open by a human.

Summary

One object of the invention is to provide an improved arrangement for controlling movements of an access member relative to a frame.

A further object of the invention is to provide an improved access member system.

A further object of the invention is to provide an improved method of controlling movements of an access member relative to a frame. These objects are achieved by the arrangement according to appended claim i, the access member system according to appended claim 12 and the method according to appended claim 13.

The invention is based on the realization that by providing a door closer comprising a spring that provides a mechanical latching of the door leaf, and in which door closer electric energy is harvested from an initial part of a closing movement and the harvested electric energy is used to drive an electric motor during a subsequent latching part of the closing movement, the mechanical latching force provided by the spring can be reduced. As a consequence, the spring can be made weaker to thereby enable the door leaf to be opened more easily by elderly persons while at the same time ensuring a sufficiently strong latching of the door leaf.

According to a first aspect, there is provided an arrangement for controlling movements of an access member relative to a frame, the arrangement comprising a drive element movable between a closed drive position and an open drive position; a mechanical force device arranged to force the drive element to move from the open drive position in a closing drive movement to the closed drive position for causing the access member to move from an open position in a closing movement to a closed position, the closing drive movement comprising a closing initial drive movement and a latching drive movement following the closing initial drive movement; a force device transmission arranged to transmit movements of the drive element to movements of the mechanical force device; and an electric machine drivingly connected to the drive element; wherein the mechanical force device and the force device transmission are configured to act more forcefully on the drive element during the latching drive movement than during the closing initial drive movement; and wherein the arrangement further comprises an electronic control system configured to control the electric machine to operate as an electric generator during the closing initial drive movement to harvest electric energy, and to control the electric machine to operate as an electric motor during the latching drive movement. The arrangement enables an access member to be opened with low force while ensuring a sufficiently strong latching of the access member and without having to electrically power the arrangement from an external power source outside the arrangement. The arrangement therefore enables an improved usability, for example for elderly persons. One example of an external power source is a mains supply.

When the drive element is in the open drive position, the mechanical force device will force the drive element towards the closed drive position in the closing drive movement. During the closing initial drive movement, the electric machine will be driven as an electric generator and thereby slow down the closing drive movement. Mechanical energy released from the mechanical force device tends to increase the speed of the closing drive movement while the mechanical energy from the closing drive movement used to drive the electric machine as an electric generator tends to decrease the speed of the closing drive movement.

At least some of the electric energy harvested by the electric generator during the closing initial drive movement may be used to drive the electric motor to provide a stronger latching in comparison with when only the mechanical force device and the force device transmission are used to provide the latching. This enables a use of a relatively weak mechanical force device in the arrangement.

Since the latching drive movement follows the closing initial drive movement, the closing initial drive movement and the latching drive movement do not overlap. The closing initial drive movement may alternatively be referred to as a non-latching drive movement. The latching drive movement may or may not start at the same time as the closing initial drive movement ends. Thus, the electric machine may be immediately switched from operation as an electric generator to operation as an electric motor when the latching drive movement starts. Alternatively, the electric machine may not be controlled to operate as an electric machine or as an electric motor during a closing intermediate drive movement between the closing initial drive movement and the latching drive movement. That is, energy harvesting may stop at one position of the drive element along the closing drive movement and the electric machine may be started to be driven as an electric motor at another later position of the drive element along the closing drive movement.

In order for the mechanical force device and the force device transmission to be able to act more forcefully on the drive element, the mechanical force device and the force device transmission may be configured to provide a higher torque and/or a higher force on the drive element. The drive element may for example be rotatable about a rotation axis between the closed drive position and the open drive position. In this case, the mechanical force device and the force device transmission may be configured to provide a higher torque on the drive element during the latching drive movement than during the closing initial drive movement. Alternatively, the drive element may be translationally movable between the closed drive position and the open drive position. In this case, the mechanical force device and the force device transmission may be configured to provide a higher force on the drive element during the latching drive movement than during the closing initial drive movement.

The latching drive movement may be the last part of the closing drive movement. After the latching drive movement, the access member may be in the closed position. When the arrangement is installed to control movements of the access member, the drive element may perform movements in accordance with movements of the access member relative to the frame, and vice versa. Thus, each position of the drive element in relation to the arrangement may correspond to a unique position of the access member in relation to the frame, and vice versa.

Throughout the present disclosure, the arrangement may be a door closer. Alternatively, or in addition, the access member may be rotatable relative to the frame. When the arrangement is installed to control movements of the access member, the open drive position and the closed drive position of the drive element may correspond to the open position and the closed position, respectively, of the access member. The arrangement may be connected to each of the access member and the frame.

The mechanical force device may be configured to store and release mechanical energy. The force device transmission may be configured to cause movements of the drive element to be transferred to potential energy in the mechanical force device. Conversely, the force device transmission may be configured to cause potential energy stored in the mechanical force device to be transferred to movements of the drive element.

The electric machine may be directly or indirectly connected to the drive element. According to one variant, the arrangement comprises an electric machine transmission that provides a driving connection between the drive element and the electric machine. The electric machine transmission may comprise a plurality of gear wheels. The electric machine transmission may be a speed increasing transmission. That is, the electric machine transmission may be configured to transmit a first speed of the drive element to a second speed of the electric machine, higher than the first speed.

The control system may comprise at least one data processing device and at least one memory having at least one computer program stored thereon, the at least one computer program comprising program code which, when executed by the at least one data processing device, causes the at least one data processing device to command control of the electric machine to operate as an electric generator and to command control of the electric machine to operate as an electric motor. The at least one computer program comprising program code which, when executed by the at least one data processing device, causes the at least one data processing device to perform, or command performance of, any step described herein. The arrangement may further comprise a sensor. The sensor may be arranged to determine a drive element position value indicative of a position of the drive element, such as any position of the drive element between the closed drive position and the open drive position. When the arrangement is installed to control movements of the access member, a position of the access member can be determined based on the drive element position value. As an alternative to the sensor, the position of the drive element can be determined based on the electric machine, such as based on a position of a rotor thereof.

The electric machine operating as an electric motor may be arranged to provide a force or a torque on the drive element that is at least 5 % of a force or a torque on the drive element provided by the mechanical force device and the force device transmission during the latching drive movement. That is, the electric machine operating as an electric motor may be arranged to provide a force on the drive element that is at least 5 % of a force on the drive element provided by the mechanical force device and the force device transmission during the latching drive movement, or the electric machine operating as an electric motor may be arranged to provide a torque on the drive element that is at least 5 % of a torque on the drive element provided by the mechanical force device and the force device transmission during the latching drive movement.

In case the access member is rotatable relative to the frame, a distance of the latching drive movement may correspond to a latching movement of the access member having an angular distance of less than 25 degrees and/or at least 3 degrees.

The drive element may be movable from the closed drive position to the open drive position in an opening drive movement comprising an opening initial drive movement and an opening subsequent drive movement. In this case, the control system may be configured to control the electric machine to operate as an electric generator during the opening subsequent drive movement but not during the opening initial drive movement. Thus, electric energy may also be harvested by the electric generator during opening without increasing a maximum force required to open the access member. When the arrangement is installed to control movements of the access member, the opening drive movement from the closed drive position to the open drive position may cause the access member to move from the closed position in an opening movement to the open position.

A length of the opening initial drive movement may be at least 50 % of a length of the latching drive movement and/ or less than 150 % of the length of the latching drive movement., such as equal to the length of the latching drive movement.

The mechanical force device may comprise a spring. The spring may be configured to store potential energy by deformation, such as by compression or by extension. The spring may for example be a coil spring. As one possible alternative, the mechanical force device may comprise one or more magnets or a force device driven by gravity.

The arrangement may comprise an electric energy storage arranged to store electric energy harvested by the electric machine when operating as an electric generator, and arranged to electrically power the electric machine when operating as an electric motor. The electric energy storage may comprise a battery and/ or a capacitor.

The control system may be configured to control the electric machine based on a speed of the drive element. For example, during the closing initial drive movement, the control of the electric machine as an electric generator may be performed to obtain a desired speed profile of the drive element, such as a relatively low speed of the drive element. Correspondingly, the during the latching drive movement, the control of the electric machine as an electric motor may be performed to obtain a desired speed profile of the drive element, such as a relatively high speed of the drive element. The speed of the drive element may be a rotational speed or a translational speed.

The arrangement may further comprise a connection device for connection between the access member and the frame. The connection device may be drivingly connected to the drive element. The connection device may comprise one or more rigid arms. In this case, one of the at least one arm may be fixed to the drive element. Alternatively, the connection device may comprise a flexible elongated element, such as a wire.

The force device transmission may comprise a cam profile and a cam follower arranged to follow the cam profile. One of the cam profile and the cam follower may be fixed to the drive element.

The control system may be arranged to be electrically powered by the electric machine.

According to a second aspect, there is provided an access member system comprising the arrangement according to the first aspect, the access member and the frame. The access member may be a door leaf or a window sash. Alternatively, or in addition, the access member may be rotatable relative to the frame or linearly movable relative to the frame. The arrangement, the access member and the frame may be of any type as described herein.

According to a third aspect, there is provided a method of controlling movements of an access member relative to a frame, the method comprising providing a drive element movable between a closed drive position and an open drive position; providing a mechanical force device arranged to force the drive element to move from the open drive position in a closing drive movement to the closed drive position to thereby cause the access member to move from an open position in a closing movement to a closed position, the closing drive movement comprising a closing initial drive movement and a latching drive movement following the closing initial drive movement; providing a force device transmission arranged to transmit movements of the drive element to movements of the mechanical force device; and providing an electric machine drivingly connected to the drive element; wherein the mechanical force device and the force device transmission are configured to act more forcefully on the drive element during the latching drive movement than during the closing initial drive movement; and wherein the method further comprises controlling the electric machine to operate as an electric generator during the closing initial drive movement to harvest electric energy, and controlling the electric machine to operate as an electric motor during the latching drive movement. The method may employ an arrangement of any type according to the first aspect and/or an access member system of any type according to the second aspect.

Brief Description of the Drawings

Further details, advantages and aspects of the present disclosure will become apparent from the following description taken in conjunction with the drawings, wherein:

Fig. i: schematically represents a perspective view of an access member system comprising a door leaf and a door closer;

Fig. 2: schematically represents a top view of the access member system when the door leaf is in a closed position;

Fig. 3: schematically represents a top view of the access member system when the door leaf is in an open position;

Fig. 4: schematically represents a partial perspective view of the door closer;

Fig. 5: schematically represents a partial top view of the door closer when a drive element is in an open drive position;

Fig. 6: schematically represents a partial top view of the door closer during a latching drive movement;

Fig. 7: schematically represents an electric energy handling arrangement;

Fig. 8: schematically represents a diagram showing torques acting on the drive element during a closing movement;

Fig. 9: schematically represents a perspective view of a further example of a door closer; and

Fig. 10: schematically represents a partial perspective view of the door closer in Fig. 9. Detailed Description

In the following, an arrangement for controlling movements of an access member relative to a frame, an access member system comprising an arrangement, and a method of controlling movements of an access member relative to a frame, will be described. The same or similar reference numerals will be used to denote the same or similar structural features.

Fig. i schematically represents a perspective view of an access member system io. The access member system io comprises a door closer 12a, a frame 14 and a door leaf 16. The door closer 12a and the door leaf 16 are examples of an arrangement and an access member, respectively, according to the present disclosure. The access member system 10 of this specific example comprises two hinges 18 enabling the door leaf 16 to rotate relative to the frame 14 about a vertical rotation axis (not shown). In Fig. 1, the door leaf 16 is in a closed position 20.

Fig. 2 schematically represents a top view of the access member system 10. Also in Fig. 2, the door leaf 16 is in the closed position 20. As shown in Fig. 2, the door closer 12a of this specific and non-limiting example comprises a primary element, here exemplified as a housing 22, and a secondary element, here exemplified as a tube 24. In this example, the tube 24 is fixed to the frame 14 and the housing 22 is fixed to the door leaf 16. The tube 24 is horizontally oriented in Fig. 2. As one alternative to the tube 24, the door closer 12a may comprise a rail that is not necessarily tubular.

The door closer 12a of this example further comprises a drive element 26a. In Fig. 2, the drive element 26a is in a closed drive position 28. The drive element 26a is rotatable about a rotation axis 30. The rotation axis 30 is here vertical and fixed to the housing 22.

The door closer 12a of this example further comprises an arm 32a. The arm 32a is one example of a connection device according to the present disclosure. The arm 32a is here straight and rigid. In Fig. 2, one end of the arm 32a is fixed to the drive element 26a, e.g. by a spline connection. The arm 32a is thereby drivingly connected to the drive element 26a. An opposite end (not denoted) of the arm 32a, such as a sliding block thereon, is slidably arranged within the tube 24. The arm 32a is thus connected between the door leaf 16 and the frame 14.

Fig. 3 schematically represents a top view of the access member system 10 when the door leaf 16 is in an open position 34. The door leaf 16 can move from the closed position 20 to the open position 34 in an opening movement 36. Conversely, the door leaf 16 can move from the open position 34 to the closed position 20 in a closing movement 38.

In Fig. 3, the open position 34 is exemplified as the door leaf 16 being rotated 90 degrees from the closed position 20. The open position 34 is however not limited to this specific level of opening of the door leaf 16.

Fig. 3 further shows a latching movement 40 of the door leaf 16 during closing. The door closer 12a causes the door leaf 16 to perform the latching movement 40. The latching movement 40 forms a last part of the closing movement 38 of the door leaf 16. The latching movement 40 in this specific and non-limiting example has an angular extension of 20 degrees.

When a human user pushes or pulls the door leaf 16 to open, the door leaf 16 performs the opening movement 36 from the closed position 20 to the open position 34. The opening movement 36 of the door leaf 16 causes the drive element 26a, and here also the arm 32a, to perform an opening drive movement 42 from the closed drive position 28 to an open drive position 44. During the opening drive movement 42 of the drive element 26a, the arm 32a rotates about the rotation axis 30 (counterclockwise in Fig. 3) and travels linearly inside the tube 24 (to the left in Fig. 3).

When the user releases the door leaf 16 in the open position 34, the door closer 12a forces drive element 26a, and here also the arm 32a, to perform a closing drive movement 46 from the open drive position 44 to the closed drive position 28. During the closing drive movement 46 of the drive element 26a, the arm 32a rotates (clockwise in Fig. 3) and travels linearly inside the tube 24 (to the right in Fig. 3). As a consequence, the door leaf 16 is forced by the door closer 12a to perform the closing movement 38 from the open position 34 to the closed position 20 including the last latching movement 40.

The open drive position 44 of the drive element 26a corresponds to the open position 34 of the door leaf 16. Conversely, the closed drive position 28 of the drive element 26a corresponds to the closed position 20 of the door leaf 16.

As shown in Fig. 3, the opening drive movement 42 comprises a closing initial drive movement 48 and a latching drive movement 50, following the closing initial drive movement 48. An angular distance of the latching drive movement 50 of the drive element 26a here corresponds to an angular distance of the latching movement 40 of the door leaf 16. The opening drive movement 42 comprises an opening initial drive movement 52 and an opening subsequent drive movement 54, following the opening initial drive movement 52. An angular distance of the opening initial drive movement 52 here equals an angular distance of the latching drive movement 50.

In this example, an angular distance of the opening movement 36 by the door leaf 16 is substantially the same, or the same, as an angular distance of the opening drive movement 42 by the drive element 26a. Conversely, an angular distance of the closing movement 38 by the door leaf 16 is substantially the same, or the same, as an angular distance of the closing drive movement 46 by the drive element 26a in this example.

The door closer 12a may further comprise a sensor (not shown). The sensor may determine a position of the drive element 26a and/or the arm 32a about the rotation axis 30 relative to the housing 22. This rotational position of the drive element 26a and/or the arm 32a about the rotation axis 30 corresponds to the rotational position of the door leaf 16 about the hinges 18.

Fig. 4 schematically represents a partial perspective view of the door closer 12a. In Fig. 4, the housing 22 is removed. As shown, the door closer 12a of this example further comprises a spring 56a, here a compression coil spring. The spring 56a is arranged to force the drive element 26a to rotate about the rotation axis 30 from the open drive position 44 to the closed drive position 28 in the closing drive movement 46. The spring 56a is one example of a mechanical force device according to the present disclosure.

The door closer 12a further comprises an electric machine 58. The electric machine 58 is drivingly connected with the drive element 26a. To this end, the door closer 12a of this specific and non-limiting example comprises an electric machine transmission 60a. The electric machine transmission 60a is configured to transmit a rotation of the drive element 26a about the rotation axis 30 to a rotation of the electric machine 58, and vice versa. The electric machine transmission 60a of this example is a speed increasing transmission such that a rotational speed of the electric machine 58 is higher than a rotational speed of the drive element 26a. The electric machine transmission 60a of this example comprises a plurality of gear wheels.

The door closer 12a further comprises a force device transmission 62a. The force device transmission 62a is arranged to transmit movements of the drive element 26a to movements of the spring 56a. More specifically, the force device transmission 62a is arranged to transmit movements of the drive element 26a in one direction (here a clockwise rotation about the rotation axis 30) to a compression of the spring 56a to store potential energy in the spring 56a, and is arranged to transmit an expansion of the spring 56a to movements of the drive element 26a in an opposite direction (here a counterclockwise rotation about the rotation axis 30) when releasing potential energy from the spring 56a.

The force device transmission 62a of this example comprises a cam profile 64a and a cam follower 66a. The cam follower 66a is arranged to engage and follow the cam profile 64a. In this example, the cam follower 66a is connected to an end piece 68 at an end of the spring 56a. The cam follower 66a is here rotatable relative to the end piece 68. The cam profile 64a is here fixed to the both the drive element 26a and the arm 32a. The door closer 12a further comprises an electronic control system 70a. The control system 70a is electrically connected to the electric machine 58 and is configured to control the electric machine 58. More specifically, the control system 70a is configured to control the electric machine 58 to operate as an electric generator during the closing initial drive movement 48 and to control the electric machine 58 to operate as an electric motor during the latching drive movement 50. By controlling the electric machine 58 to operate as an electric generator during the closing initial drive movement 48, electric energy can be harvested. By controlling the electric machine 58 to operate as an electric motor during the latching drive movement 50, the electric machine 58 can assist the spring 56a to provide a latching torque on the door leaf 16.

The door closer 12a of this example further comprises an electric energy storage 72a, here exemplified as three capacitors. The electric energy storage 72a is configured to store electric energy harvested by the electric machine 58 when operating as an electric generator, and arranged to electrically power the electric machine 58 when operating as an electric motor. Also the control system 70a is here electrically powered by the electric machine 58, either directly or indirectly via the electric energy storage 72a.

As can be understood from Fig. 4, the spring 56a, the force device transmission 62a, the electric machine transmission 60a, the electric machine 58, the electric energy storage 72a and the control system 70a are positioned inside the housing 22.

Fig. 5 schematically represents a partial top view of the door closer 12a. The drive element 26a is in an open drive position 44 and has just initiated the closing initial drive movement 48, e.g. due to the door leaf 16 being released by the user in the open position 34. In the open drive position 44 in Fig. 5, the drive element 26a has been rotated approximately 170 degrees from the closed drive position 28. Thus, the open drive position 44 in Fig. 5 differs from the open drive position 44 in Fig. 3. However, the open drive position 44 maybe different for each opening/ closing cycle, e.g. depending on at which position the user releases the door leaf 16.

The cam profile 64a of this specific and non-limiting example comprises a latching portion 74 and a non-latching portion 76. The latching portion 74 is concave in a plane transverse to the rotation axis 30. The non-latching portion 76 is convex in the plane transverse to the rotation axis 30. The nonlatching portion 76 has a successively decreasing radius (with respect to the rotation axis 30) in a circumferential direction towards the latching portion 74. The cam follower 66a of this example is round and rotatable relative to the end piece 68.

In the open drive position 44, the cam follower 66a contacts the non-latching portion 76 and the spring 56a is compressed to store potential energy. During the closing initial drive movement 48, the cam follower 66a travels along the non-latching portion 76 due to the release of potential energy from the spring 56a.

Fig. 5 shows a line of action 78 along which the force from the spring 56a and the cam follower 66a acts on the cam profile 64a. In the open drive position 44, the spring 56a is compressed to a relatively large extent. However, a distance 80 between the line of action 78 and the rotation axis 30 is relatively small. As a consequence, a torque generated by the spring 56a and the force device transmission 62a on the drive element 26a is relatively low.

Fig. 6 schematically represents a partial top view of the door closer 12a during the latching drive movement 50. During the latching drive movement 50, the cam follower 66a contacts and travels along the latching portion 74 while potential energy from the spring 56a is released to the drive element 26a. Although the spring 56a is less deformed in Fig. 6 than in Fig. 5, the distance 80 between the line of action 78 and the rotation axis 30 is relatively large. As a consequence, a torque generated by the spring 56a and the force device transmission 62a on the drive element 26a is relatively high. The spring 56a and the cam follower 66a are thus arranged to exert a force on the cam profile 64a along the line of action 78 such that the distance 80 between the rotation axis 30 and the line of action 78 is larger during the latching drive movement 50 than during the closing initial drive movement 48. In this way, the spring 56a and the force device transmission 62a are configured to act more forcefully on the drive element 26a during the latching drive movement 50 than during the closing initial drive movement 48.

Fig. 7 schematically represents one non-limiting example of an electric energy handling arrangement 82 comprising the electric machine 58 and the control system 70a. The electric machine 58 of this example is a DC (direct current) electric machine. The electric machine 58 comprises a stator 84 and a rotor 86 rotatable relative to the stator 84. The rotor 86 is here rotationally driven by the electric machine transmission 60a. The control system 70a of the specific example in Fig. 7 comprises power management electronics 88 and a microcontroller 90. The microcontroller 90 comprises a data processing device 92 and a memory 94. A computer program is stored in the memory 94. The computer program comprises program code which, when executed by the data processing device 92 causes the data processing device 92 to perform, or command performance of, various steps as described herein.

The power management electronics 88 in Fig. 7 comprises four diodes 96 arranged in a diode bridge. The diodes 96 are arranged to rectify the voltage from the electric machine 58 when operating as an electric generator.

The electric energy handling arrangement 82 further comprises a disconnection switch 98. The disconnection switch 98 is electrically powered by the electric machine 58 when operating as an electric generator.

The disconnection switch 98 is controlled by the control system 70a, more specifically by the microcontroller 90. Fig. 7 further shows a positive line 100 and a ground line 102. The positive line 100 and the ground line 102 are connected to respective terminals of the electric machine 58. In this example, the disconnection switch 98 is provided on the positive line 100. The disconnection switch 98 maybe implemented using a transistor, such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

The disconnection switch 98 is arranged to selectively disconnect the electric machine 58. When the disconnection switch 98 is open, the electric resistance becomes high, and the rotor 86 rotates lightly, in comparison with when the rotor 86 is rotated to harvest electric energy.

By selectively controlling the disconnection switch 98, the control system 70a can selectively change a load of the electric machine 58. The control system 70a is configured to control opening and closing of the disconnection switch 98 to control a speed of the drive element 26a. By applying electrical power to the electric machine 58 from the electric energy storage 72a, the electric machine 58 can be operated as an electric motor to drive the drive element 26a.

Fig. 8 schematically represents a diagram showing torques 104 acting on the drive element 26a during the closing movement 38. More specifically, Fig. 8 shows a spring torque 106 generated by the spring 56a and the force device transmission 62a and acting on the drive element 26a, and a total torque 108 acting on the drive element 26a, as a function of a position no of the drive element 26a during the closing movement 38. The position no of the drive element 26a is in this example a rotational position about the rotation axis 30.

Fig. 8 further schematically shows some non-limiting examples of torque requirements that may be present for an implementation of the door closer 12a. The torque requirements may be imposed by regulations and/ or standards for a particular implementation in a particular jurisdiction. Fig. 8 shows a first torque requirement 112a defining a maximum torque 104 during the closing movement 38, a second torque requirement 112b defining a minimum torque 104 for latching, and a third torque requirement 112c defining a minimum torque 104 of the closing movement 38 until the latching. Additional or fewer torque requirements on the torque 104 may be present.

During the closing initial drive movement 48, the control system 70a controls the electric machine 58 to operate as an electric generator and the harvested electric energy is stored in the electric energy storage 72a. Since the operation of the electric machine 58 as electric generator brakes the drive element 26a, the total torque 108 is lower than the spring torque 106 during the closing initial drive movement 48. The area below the spring torque 106 and above the total torque 108 during the closing initial drive movement 48 represents electric energy 114 harvested by the electric machine 58 operating as an electric generator.

When the closing initial drive movement 48 ends and the drive element 26a enters the latching drive movement 50, the control system 70a controls the electric machine 58 to operate as an electric motor by electric energy from the electric energy storage 72a. During the latching drive movement 50, the spring 56a and the electric machine 58 act in parallel on the drive element 26a. Since the operation of the electric machine 58 as an electric motor adds torque to the drive element 26a, the total torque 108 is higher than the spring torque 106 during the latching drive movement 50. The area below the total torque 108 and the above the spring torque 106 during the latching drive movement 50 represents electric energy 116 added by the electric machine 58 when operating as an electric motor. The amount of added electric energy 116 affects the latching torque acting on the door leaf 16. Just before the closed drive position 28, the torque 104 provided by the electric machine 58 operating as an electric motor amounts to approximately 20 % of the spring torque 106 in this example. Both during the closing initial drive movement 48 and the latching drive movement 50, the control system 70a may control the electric machine 58 based on a speed of the drive element 26a.

Due to the ability of the electric machine 58 to operate both as an electric generator and as an electric motor during the closing movement 38, a relatively weak spring 56a can be used while still ensuring a sufficient latching of the door leaf 16.

In this example, electric energy is not harvested by the electric machine 58 during the opening initial drive movement 52 of the opening drive movement 42. The user opening the door leaf 16 thus only has to overcome the spring torque 106 during the opening initial drive movement 52. Since the spring 56a is relatively weak, usability is improved since the door leaf 16 can more easily be opened from the closed position 20 through a latching region in comparison with if using a relatively strong spring that provides all the latching force. During the opening subsequent drive movement 54 of the opening drive movement 42, the electric machine 58 may or may not be operated as an electric generator to harvest electric energy.

Fig. 9 schematically represents a perspective view of a further example of a door closer 12b. Mainly differences between the door closer 12b and the door closer 12a will be described. The door closer 12b comprises a drive element 26b, a force device transmission 62b and an arm 32b. The drive element 26b is here exemplified as a plate and is fixed to the door leaf 16. The arm 32b is a further example of a connection device according to the present disclosure.

The force device transmission 62b comprises a cam profile 64b and a cam follower 66b. The cam profile 64b is here exemplified as a groove in the drive element 26b. The cam profile 64b lies in a horizontal plane. The cam follower 66b is exemplified as a roller in the arm 32b. The roller is rotatable about a vertical axis and engages in the cam profile 64b. The cam follower 66b is thereby arranged to follow and move along the cam profile 64b.

The cam profile 64b of this example comprises a straight section 118 and a curved section 120. In the closed drive position 28 of the drive element 26b and the closed position 20 of the door leaf 16, the cam follower 66b is positioned in the end of the curved section 120. In the open drive position 44 of the drive element 26b and the open position 34 of the door leaf 16, the cam follower 66b is positioned in the straight section 118. The curved section 120 faces away from the tube 24 in the closed drive position 28. The straight section 118 is here horizontal and parallel with a main extension plane of the door leaf 16.

Fig. 10 schematically represents a partial perspective view of the door closer 12b in Fig. 9. The view in Fig. 10 differs from Fig. 9 in that the tube 24 has been removed. As shown in Fig. 10, the door closer 12b further comprises a spring 56b. The force device transmission 62b is arranged to transmit movements of the drive element 26b to deformations of the spring 56b. The spring 56b is arranged to force the arm 32b to pull the drive element 26b from the open drive position 44 in the closing drive movement 46 to the closed drive position 28 for causing the door leaf 16 to move from the open position 34 in the closing movement 38 to the closed position 20. The spring 56b is a further example of a mechanical forcing device according to the present disclosure. The arm 32b is fixed to the end piece 68.

The spring 56b of this specific example is a tension coil spring. One end (the left end in Fig. 10) of the spring 56b is fixed to the end piece 68, and the other end (the right end in Fig. 10) of the spring 56b is fixed to the tube 24. The spring 56b is arranged inside the tube 24.

During the closing initial drive movement 48, the cam follower 66b engages the straight section 118. During the latching drive movement 50, the cam follower 66b engages the curved section 120. As a consequence, the spring 56b and the force device transmission 62b are configured to provide a higher force on the drive element 26b during the latching drive movement 50 than during the closing initial drive movement 48.

The electric machine 58 is drivingly connected to the drive element 26b. To this end, the door closer 12b of this specific example further comprises a electric machine transmission 60b, a rotatable first pulley 122, a rotatable second pulley 124 and a flexible elongated element, here exemplified as a belt 126. The belt 126 is wound in a closed loop around the first pulley 122 and the second pulley 124. The movement of the belt 126 drives the first pulley 122 and the second pulley 124 to rotate. The end piece 68 is arranged inside the loop and is fixed to one side of the belt 126.

The electric machine transmission 60b transmits a rotation of the first pulley 122 to a rotation of the rotor 86 of the electric machine 58. The electric machine transmission 60b is a speed increasing transmission such that the rotor 86 rotates faster than the first pulley 122. The electric machine transmission 60b of this example comprises a plurality of serial spur gears. The electric machine transmission 60b may alternatively comprise a planetary gearing.

The door closer 12b further comprises an electronic control system 70b and an electric energy storage 72b of the same type as the control system 70a and the electric energy storage 72a. The electric energy storage 72b stores electric energy generated by the electric machine 58. The control system 70b is electrically powered by the electric energy storage 72b. The electric machine 58 is thereby arranged to electrically power the control system 70b without the need of external hardwiring. The control system 70b is configured to control the electric machine 58 to operate as an electric generator during the closing initial drive movement 48 to harvest electric energy, and to control the electric machine 58 to operate as an electric motor during the latching drive movement 50. Each of the first pulley 122, the second pulley 124, the belt 126, the electric machine transmission 60b, the electric machine 58, the control system 70b and the electric energy storage 72b are also arranged inside the tube 24.

While the present disclosure has been described with reference to exemplary embodiments, it will be appreciated that the present invention is not limited to what has been described above. For example, it will be appreciated that the dimensions of the parts maybe varied as needed. Accordingly, it is intended that the present invention may be limited only by the scope of the claims appended hereto.