GB2576071A

GB2576071A - Drive for a door or window sash

Info

Publication number: GB2576071A
Application number: GB1907566.2A
Authority: GB
Inventors: Woerner Benjamin
Original assignee: Geze GmbH
Current assignee: Geze GmbH
Priority date: 2018-05-30
Filing date: 2019-05-29
Publication date: 2020-02-05
Anticipated expiration: 2039-05-29
Also published as: DE102018208592A1; AT521331A2; CN110552572B; FR3081904A1; GB2576071B; FR3081904B1; CN110552572A; GB201907566D0

Abstract

The drive 10 comprises a piston 16 slidably guided in a housing 12, a spring 14, an output shaft 20 and a rack-and-pinion gear 18 with an out-of-round pinion 22 with teeth 24 and counter-teeth 26 on the piston side, wherein the effective lever arm length of the pinion teeth decreases upon opening of the sash up to a first opening angle, then after a second opening angle the length increases abruptly with an increasing opening angle. The line of action of a pair of teeth is produced by a profile shift varying when rolling over the curve. At least one tooth pair may be provided with pressure-side tooth flanks that are extended in comparison with the flanks of the remaining teeth pairs for generating the abruptly increasing lever arm length. The pinion and piston may be driven in both directions and the piston may be hollow with internal toothing.

Description

DRIVE FOR A DOOR OR WINDOW SASH

The invention relates to a drive for a sash of a door, a window or the like, having a housing, a piston that is slidably guided in the housing and acted on by a spring unit and an output shaft that is rotatably mounted in the housing and connected with the piston by a rack and pinion gear.

More specifically, such a drive can be a door closer.

In a drive of the type mentioned above, when opening and closing the sash, the output shaft and thus the pinion is rotated, whereby the piston is axially displaced in the housing by means of the out-of-round rack and pinion gear during opening of the sash against the force of the spring unit, usually comprising a compression spring. The spring unit thus generates the opening and closing moment of the drive or door closer.

In order to meet the increasingly stringent requirements for accessibility when walking through doors, an opening moment of the door and thus of the drive is required that drops steeply when opening the door.

Door closers with a rack and pinion gear usually only achieve very weakly dropping opening moments, with which the aforementioned accessibility requirements are not achieved. In some cases, the opening moments even increase when the door is opened. In order to generate a corresponding drop in moment, additional components are thus required.

By using a cam disk gear in the door closer, the required drop in moment can indeed be realized relatively easily. However, these door closers are more complex in construction and therefore more expensive than door closers with a rack and pinion gear. In addition, the efficiency and the damping performance are often poorer than door closers with a rack and pinion gear.

Door closers with a scissor linkage as a power transmission device between the output shaft and the door sash or frame have in principle, by the high gear ratio drop of the linkage when opening the door, a steep dropping opening moment, wherein the gearbox in the door closer can be embodied arbitrarily. With a power transmission device with a lever or a sliding arm guided in a slide rail, the gear ratio does not drop so steeply that the gearbox in the door closer must have a higher gear ratio drop for a dropping opening moment. In order to meet the increasing demands for comfort and accessibility, door closers having, between the output shaft and the sash, a power transmission device comprising a sliding arm guided in a slide rail are designed nowadays almost exclusively with a cam disk gear, which allows a steeply decreasing gear ratio or steeply dropping opening moments on the door, making the door easy to access. The respective drop of the gear ratio or the opening moments is strongly pronounced by design and occurs especially in door closers with door opening angles up to 180°, which however now involves a lower closing moment, whereby secure closing of the door is no longer guaranteed, especially for doors in outdoor areas, which are exposed to wind loads and the like. Therefore, a mean drop in the door moments would be preferable.

In addition, door closers with cam disk gears have significantly lower piston strokes compared to door closers with a rack and pinion gear and require higher spring forces since the effective lever arm in the gearbox is smaller. As a result, door closers with a cam disk gear have poorer hydraulic damping properties and higher component loads. In addition, due to the design, cam disk gears have higher lateral forces or friction forces in the area of the power-transmitting piston than a rack and pinion gear, resulting in higher wear, poorer service life of the components, and a poorer efficiency of the door closer. In addition, door closers with cam disk gears are usually more complex in construction and thus more expensive than door closers with rack and pinion gears.

The hitherto conventional door closers with rack and pinion gears generate a barely dropping opening moment despite the out-of-round rack and pinion gear. In DE 36 38 353 and DE 93 19 547, door closers with a rack and pinion gear with out-of-round toothing are described, in which the effective lever arm of the gearbox shortens up to a predetermined door opening angle to produce a dropping opening moment. However, the gear ratio of the gearbox of these known rack and pinion gears drops too little in an initial opening range to allow a drop of opening moment comparable to that of cam disk gears. In an initial sash opening angle range, the effective lever arm shortens to only about 65% of the initial value at 0° sash opening angle. Upon further opening of the door, the effective lever arm remains virtually constant for large door opening angles or shortens even further.

In addition, a very small spring rate of the compression spring would be required for a sharp drop in the opening moment, whereby the closing moments would be too small for large door opening angles due to the small effective lever arm length of the gearbox at these large door opening angles and the low spring force. In order to produce a sufficient closing moment for large door opening angles, a high spring rate must be selected here. Thus, the opening moment on the door results from the gear ratio of the power transmission device between the output shaft and the sash or frame and the output moment of the door closer on the door closer pinion, which results from the product of the effective lever arm length of the gearbox and the spring force. The spring rate of the compression spring must be chosen to be so high here that the increase in the spring force is sufficient to compensate for the drop in the gear ratio of the power transmission device and thus to produce a sufficient closing moment to close the door safely even for large door opening angles. As a result, when the door is opened, the force of the compression spring now increases faster than it can compensate for the shortening effective lever arm of the out-of-round toothing. The decrease in the gear ratio is too low over the rotation angle of the pinion, whereby only a small drop in the opening moment is achieved. However, the gear ratio drop in the gearbox would have to be higher for adequate accessibility.

In DE 44 44 131, a door closer with a rack and pinion gear having an out-of-round toothing is described, which should produce a dropping opening moment. For this purpose, the pinion has a specially shaped first tooth, which engages with the surface which is located between the tooth tip and the pressure-side tooth flank, in the tooth foot area of the counter-toothing on the piston.

Since the main reduction of the effective lever arm length of the gearbox takes place by rolling the first pair of teeth that engage with the second when the door is opened, the height difference between the first and second teeth on the piston must be designed to be very large to facilitate a dropping opening moment similar to that of cam disk gears. However, with the known design, this is not feasible because the pressure angles of the pinion in the piston teeth at the transfer point from the first to the next tooth are too large due to the large difference in height of the first two teeth on the piston, consequently when closing the door a selfinhibition effect I jamming of the system, in the worst case, or at least a drop in efficiency and signs of wear would occur. With the known design, the effective lever arm shortens in an initial sash opening angle range only to about 64% of the initial value at 0° sash opening angle. In addition, the longer tooth is exposed to very high bending loads due to its elongated shape and the contact region at the tooth tip, which impairs the robustness of the system.

The contact region in the tooth tip on the pinion is usually represented by a rounding, which is very small as a result of geometry, causing extreme surface pressures that can quickly lead to damage of the toothing. The system is thus only suitable for door closers with low closing force (lower spring forces) for which a dropping opening moment is now again no longer relevant since the opening moments are already very low. In addition, the wear of the toothing is increased by the predominantly sliding teeth.

In addition, by design, such a conventional system has relatively large pressureside tooth flank angles (> 35° with a door opening angle of 0°) on the first tooth of the toothing of the piston, which generate very high transverse forces that impair the efficiency of the door closer, which in turn results in greatly increased opening moments of the door closer and increased wear.

If the dropping opening moments in door closers are realized by gear ratio ratios dropping to a low value, then the movement of the damping piston in the door closer is lower at lower gear ratios, which leads to poorer damping properties.

In addition, in certain assembly and/or mounting types, the gear ratio of the powertransmitting linkage is stronger than in the standard assembly, whereby the already lower opening moments and closing moments drop too far to be able to continue to meet existing standards.

The object of the invention is to propose a drive or door closer of the type mentioned above in which the previously mentioned disadvantages have been eliminated. In this case, a drive provided with a rack and pinion gear should exhibit a dropping opening moment that particularly fulfils the current requirements for accessibility and improved opening damping properties, with the simplest possible and correspondingly inexpensive construction and in compliance with the current standards in all types of assembly. In addition, the drive should also particularly have a sufficient closing moment against wind loads and the like, highest possible efficiency even without special sliding rings on the piston and a high resistance to wear.

The object is achieved according to the invention by a drive having the features of claim 1. Preferred embodiments of the drive according to the invention result from the dependent claims, the present description and the drawing.

The drive according to the invention for a sash of a door, a window or the like comprises a housing, a piston that is slidably guided in the housing and acted on by a spring unit, and an output shaft that is rotatably mounted in the housing and connected with the piston by a rack and pinion gear. The rack and pinion gear comprises an out-of-round pinion connected to the output shaft, the toothing of which meshes with a counter-toothing on the piston side. In this case, the effective lever arm length of the pinion-side toothing decreases in an initial sash opening angle range of 0° to a first predetermined sash opening angle, starting from a relatively higher or maximum effective lever arm length at the sash opening angle of 0° with increasing sash opening angle, while from a second predetermined sash opening angle, which is greater than or equal to the first predetermined sash opening angle and smaller than the maximum sash opening angle, it increases abruptly with an increasing sash opening angle.

In this case, a tooth pair of each of the pinion-side and piston-side toothing that engage with one another in the initial sash opening angle range is preferably designed such that, during opening of the sash, line of action, that extends horizontally, i.e. parallel to the direction of displacement of the piston, or rises relative to the horizontal or the direction of displacement of the piston results.

Due to this design, the drive provided with a rack and pinion gear has, with a simple and correspondingly cost-effective design, both a steeply dropping opening moment fulfilling the current requirements for accessibility that is comparable to that of a cam disk gear as well as improved opening damping properties. In addition, the drive according to the invention can be used in compliance with the current standards in all types of stops. In addition, the drive according to the invention also particularly has a sufficient closing moment against wind loads and the like, highest possible efficiency even without special sliding rings on the piston, and a high resistance to wear. While the opening moment of the drive can drop relatively abruptly in an initial door opening angle range due to a gear ratio dropping to a low value, the opening and closing moment increases abruptly again from the second predetermined sash opening angle. Due to the correspondingly enlarged effective lever arm length of the pinion-side toothing, less counterpressure is required for the opening damping of the sash in order to decelerate the piston connected to the sash. Due to the lower counterpressure, the material loads on the drive are lower, whereby the components must also withstand lower pressures. In addition, the increased effective lever arm length increases the stroke of the piston, whereby more hydraulic fluid is displaced over a specific sash opening angle range such that the flow control valves are also subjected to less stress. Due to the increased closing moment, the increased gear ratio drop of the power-transmitting linkage in certain stop or mounting types (e.g. when mounted on the opposite hinge side, head or frame mounting, etc.) is also compensated such that the drive in all stop or mounting types fulfils the minimum closing moments of the existing standards.

By designing a tooth pair of each of the pinion-side and piston-side toothing that engage with one another in the initial sash opening angle range such that, during opening of the sash, a horizontally extending or rising line of action is produced, very small tooth flank angles of the first tooth flank engaging with the pinion-side toothing on the pressure side during opening of the sash can be realised at the piston (particularly smaller than 25°, preferably smaller than 20°). Thus, only small transverse forces are transmitted from the piston to the housing, whereby the friction is reduced. Due to the reduced friction, high efficiency of the drive is achieved while reducing wear, which increases the service life of the drive. Due to the high efficiency, a considerably lower initial opening moment of the sash can be achieved than for door closers with a cam disk gear with the same closing moment of the drive, whereby the access comfort is increased accordingly.

The horizontal or rising course of the line of action of a pair of teeth of the pinionside and piston-side toothings, which respectively engage with each other in the initial sash opening angle range, is produced at least partially by a profile shift varying accordingly when rolling over the rolling curve and/or a module varying accordingly when rolling over the rolling curve and/or flank angles varying accordingly when rolling over the rolling curve and/or radii of curvature of the tooth flanks of the pinion-side toothing varying accordingly when rolling over the rolling curve.

Profile shift is a term from the field of gearings and mechanisms. In the design and manufacture of gearwheels with a profile shift, the shape of the teeth is changed, but without changing the underlying base curve. In the case of a gearwheel with a profile shift, a different part of the same curve (usually involute or cycloid) is used as the tooth flank compared to a gear without a profile shift. The module is a gauge for the size of the teeth of gearwheels. It is defined as the quotient of the gearwheel partition or the distance between two adjacent teeth and pi, which is a mathematical constant defined which is defined as the ratio of the circumference of a circle to its diameter.

By the teeth meshing with one another in the initial sash opening angle range, and in particular the first tooth pair of the pinion-side and piston-side toothings, during opening of the sash, having a horizontal or rising line of action due to a varying profile shift and/or a varying module and/or varying flank angles and/or varying radii of curvature of the tooth flanks during opening of the sash, a shorter contact length of the relevant tooth pairs is achieved in certain regions, which allows a rapid shortening of the effective lever arm length of the rack and pinion gear such that the sash moment drops steeply upon a further opening of the sash, whereby a more comfortable access is facilitated. In addition, an advantageous engagement of the first pair of teeth at particularly small flank angles is made possible by a rising line of action in combination with the special shape of the first pair of teeth, with flank angles varying on the pinion-side and piston-side tooth, in order to reduce the transverse forces and to increase the efficiency. Due to the curve shape of the line of action, also referred to as the so-called engagement line, this could also be referred to as an engagement curve. The point of contact of the flanks ofthe intermeshing teeth runs on the line of action. The line of action initially drops somewhat with a tooth engagement behind the centre line of the pinion. With an appropriate assembly, however, it can be ensured that an effective tooth engagement takes place only from the centre line of the pinion where the line of action accordingly rises or extends horizontally.

Due to the shape according to the invention ofthe toothing, the effective lever arm length of the rack and pinion gear and thus the gear ratio of the gearbox in the initial sash opening angle range (rolling curve increases massively) drops steeply, whereby the opening moment drops very steeply comparable to that of a cam disk gear, thus allowing comfortable, child-friendly and accessible access through the door.

According to a preferred practical embodiment ofthe drive according to the invention, the toothings of the rack and pinion gear are designed such that its gear ratio, starting from an initial value with the sash closed, drops by the end of a sash opening angle of 40°, preferably a sash opening angle of 30°, to at least 60%, preferably to at least 55% of the initial value. This results in a correspondingly steeply dropping opening moment of the sash and accordingly a high accessibility. For example, a sash opening angle of 30° corresponds to an axle angle of approximately 48°.

The first pressure-side tooth flank of the piston-side counter-toothing, which engages with the pinion-side toothing during opening of the sash, preferably has a tooth flank angle which is less than 25°, preferably less than 20°.

The initial sash opening angle preferably reaches from 0° to a first predetermined sash opening angle in the range of 40°, preferably up to a first predetermined sash opening angle in the range of 30°.

The effective lever arm length of the pinion-side toothing preferably increases abruptly from a second predetermined sash opening angle in the range of about 60° to about 65°, preferably from 60°, with increasing sash opening angle.

It is particularly advantageous if the effective lever arm length of the pinion-side toothing increases abruptly up to a sash opening angle in the range of 70°. The improved opening damping properties and increased closing moments are achieved in this case in a sash opening angle range from about 70°.

The effective lever arm length of the pinion-side toothing can continue to drop or at least remain substantially the same in the sash opening angle range between the first predetermined sash opening angle and the second predetermined sash opening angle. Thus, for example, the drive can have a low opening moment up to about 60°, while the opening and closing moment, for example, increases abruptly from about 60° or at the latest 65°.

According to a preferred practical embodiment of the drive according to the invention, at least one engaging tooth pair of the pinion-side and piston-side toothings is provided with pressure-side tooth flanks that are extended in comparison with the pressure-side tooth flanks of the remaining tooth pairs for generating the abruptly increasing effective lever arm length of the pinion-side toothing or the associated rolling curve increase.

The abrupt increase in the opening and closing moment can thus be achieved by at least one correspondingly specially shaped pair of teeth with extended pressure-side tooth flanks on the piston and pinion of the gearbox. As a result of the special shaping of the relevant piston and pinion side teeth realised by the relatively greatly enlarged pressure-side tooth flanks, a jump in the rolling curve or the effective lever arm of the toothing results. For this purpose, the pressure-side tooth flank on the side of the pinion can have very large radii of curvature. The greater the radii of curvature of the tooth flank are designed on a respective pinion-side tooth, the more abruptly the effective lever arm enlarges during rotation of the pinion. The abrupt increase in the lever arm is maximal in, for example, almost linear radii of curvature (radius = »).

The sudden increase in the effective lever arm length of the pinion-side toothing, in particular by at least 40%, preferably by at least 60%, preferably takes place during the engagement of the at least one tooth pair with extended pressure-side tooth flanks.

It is also particularly advantageous if the at least one tooth pair of the pinion-side and piston-side toothings engage with extended pressure-side tooth flanks from a sash opening angle in the range of 60°.

In principle, however, the rolling curve increase realized by the at least one specially shaped pair of teeth of the rack and pinion gear can also be applied at any other sash opening angle between the second predetermined sash opening angle and the maximum sash opening angle.

Preferably, the toothing of the rack and pinion gear is designed such that the pinion and the piston can be driven in both directions. In vandalism cases, a clean rolling of the toothing is thus guaranteed.

Preferably, at least one respective portion of the pinion-side toothing, with decreasing effective wing lever length during opening of the sash, and a respective portion of the pinion-side toothing, with re-increasing effective lever arm length during opening of the sash, are produced at least partially by a profile shift varying accordingly when rolling over the rolling curve and/or a module varying accordingly when rolling over the rolling curve and/or flank angles varying accordingly when rolling over the rolling curve and/or radii of curvature of the tooth flanks of the pinion-side toothing varying accordingly when rolling over the rolling curve.

With larger sash opening angles and with larger spring forces, in order to facilitate the lowest possible wear and highest possible efficiency, the pressure-side tooth flanks of the teeth of the piston-side counter-toothing, which engage with the pinion-side toothing at sash opening angles in a sash opening angle range of about 60° to a maximum sash opening angle of particularly 180° and particularly in the range of the maximum sash opening angle, each preferably have a tooth flank angle which is smaller than 20°, preferably smaller than 15°.

The piston is preferably designed as a hollow piston with an internal toothing. The piston-side toothing is thus provided within the piston in this case.

The invention will be explained in more detail below on the basis of an exemplary embodiment with reference to the drawing, in which:

Fig. 1 shows a schematic representation of the basic structure of an exemplary embodiment of a drive according to the invention,

Fig. 2	shows a schematic partial representation of the out-of-round rack and pinion gear of the drive according to Fig. 1 with a sash opening angle of 0°,
Fig. 3	shows two schematic partial representations of the out-ofround rack and pinion gear of the drive according to Fig. 1 with a sash opening angle of 0° and a sash opening angle of 30°,
Fig. 4	shows two schematic partial representations of the out-ofround rack and pinion gear of the drive according to Fig. 1 with a sash opening angle of 60° and a sash opening angle of 70°,
Fig. 5	shows an enlarged representation of the tooth pair that is provided with enlarged pressure-side tooth flanks for generating the rolling curve increase of the out-of-round rack and pinion gear of the drive according to Fig. 1 with a sash opening angle of 60°,
Fig. 6	shows a schematic representation of the out-of-round rack and pinion gear of the drive according to Fig. 1, from which the effective lever arm length of the pinion-side toothing of the drive according to Fig. 1 can be seen from a sash opening angle of 90°, and
Fig. 7	shows a diagram, in which the course that is dependent on the sash opening angle of the opening and closing moment of the exemplary embodiment of the drive according to the invention according to Fig. 1, with a abruptly dropping

opening moment in an initial sash opening angle range and increased closing moments in the range from a sash opening angle of 70°, is contrasted with that of a drive with a conventional rack and pinion gear and that of a conventional drive with a cam disk gear.

Fig. 1 shows the basic structure of an exemplary embodiment of a drive 10 according to the invention for a sash of a door, which is designed in the present case, for example, as a door closer. In Figs. 2 to 6, the out-of-round rack and pinion gear of the drive 10 according to in Fig. 1 is reproduced with different sash opening angles.

As can be seen particularly from Fig. 1, the drive 10 comprises a housing 12, a piston 16 that is slidably guided in the housing 12 and acted on by a spring unit 14, and an output shaft 20 that is rotatably mounted in the housing 12 and connected with the piston 16 by a rack and pinion gear 18. The spring unit 14 comprises in the present case, for example, a compression spring.

The rack and pinion gear 18 comprises an out-of-round pinion 22 connected to the output shaft 20, the toothing 24 of which meshes with a counter-toothing 26 on the piston side.

When opening and closing the sash, the output shaft 20 is rotated with the pinion 22 and displaced over the out-of-round rack and pinion gear 18 of the piston 16 in the housing, whereby the spring unit 14 is tensioned with the opening of the wing and relaxed again with the closing of the wing. The spring unit 14 thus serves as a mechanical energy store of the drive 10.

The first pressure-side tooth flank 36 of the piston-side counter-toothing 26, which engages with the pinion-side toothing 24 during opening of the sash, has a tooth flank anglea which is less than 25°, preferably less than 20°.In the present exemplary embodiment, this tooth flank angle a is for example 21° (see Fig. 2).

As can be seen particularly from Fig. 3, the effective lever arm length R decreases in an initial sash opening angle range of 0° to a first predetermined sash opening angle of for example 30°, starting from a relatively higher, in this case maximum effective lever arm length Ro at the sash opening angle of 0° with increasing sash opening angle, while from a second predetermined sash opening angle, it increases abruptly in the present case for example from a second predetermined sash opening angle range of 60° (see Fig. 4). A tooth pair 38, 40 of each of the pinion-side and piston-side toothings 24 and 26 that engage with one another in the initial sash opening angle range is designed such that during opening of the sash a line of action 42 rising relative to the horizontal, i.e. the direction of displacement of the piston 16, results (see Fig. 2).

In the case of a tooth engagement, the line of action 42 only increases from the centre line 46 of the pinion 22 extending through the centre point of the output shaft 20 and the first pinion-side tooth 34, while it may drop slightly behind the centre line 46. Through appropriate mounting, however, a tooth engagement behind the centre line 46 can be excluded.

The rising course of the line of action 42 of a pair of teeth 38, 40 of the pinion-side and piston-side toothings 24 or 26, which respectively engage with each other in the initial sash opening angle range, can at least partially be produced by a profile shift varying accordingly when rolling over the rolling curve 44 and/or a module varying accordingly when rolling over the rolling curve 44 and/or flank angles varying accordingly when rolling over the rolling curve 44 and/or radii of curvature of the tooth flanks of the pinion-side toothing 24 varying accordingly when rolling over the rolling curve.

The rolling curve 44 (see in particular Fig. 3) describes the force transmission points between the pinion-side and piston-side toothings 24 and 26, respectively, over the actuation cycle of the drive 10.

The initial sash opening angle range in the present exemplary embodiment extends from 0° to a first predetermined sash opening angle in the range of 30°.

It is particularly advantageous if the toothings 24 of the rack and pinion gear 18 are designed such that its gear ratio, starting from an initial value with the sash closed, i.e. a sash opening angle of 0°, drops by the end of a sash opening angle of 40°, preferably by a sash opening angle of 30°, to at least 60%, preferably to at least 55% of the initial value.

The effective lever arm length R of the pinion-side toothing 24 can particularly increase abruptly from a second predetermined sash opening angle in the range of about 60° to about 65° with increasing sash opening angle, whereby it increases abruptly in the present case, for example, from a second predetermined sash opening angle of 60° (see in particular Fig. 4a)). As can be seen in particular from Fig. 3b), the effective lever arm length R of the pinion-side toothing 24 may increase abruptly, for example up to a sash opening angle in the range of 70°. The increased opening and closing moment caused by the abruptly increasing effective lever arm length is therefore achieved in the present case at a sash opening angle of 70°.

The effective lever arm length R of the pinion-side toothing 24 can continue to drop or at least remain substantially the same in the opening angle range between the first predetermined sash opening angle in the range of for example 30° and the second predetermined sash opening angle in the range of for example 60° to about 65°.

At least one engaging tooth pair 28, 30 of the pinion-side and piston-side toothings 24 and 26 can be provided with pressure-side tooth flanks that are extended in comparison with the pressure-side tooth flanks 28’, 30 ’of the remaining tooth pairs for generating the abruptly increasing effective lever arm length R of the pinionside toothing 24 or the associated rolling curve increase 48. In the present exemplary embodiment, only one such pair of teeth 28, 30 is provided with extended pressure-side tooth flanks 28’, 30’ (see particularly Figures 4 and 5).

The effective lever arm length R of the pinion-side toothing 24 may increase by at least 40% due to its sudden increase, whereby in the present exemplary embodiment it increases by at least 60% (see particularly Fig. 4).

As can be seen again in particular with reference to Fig. 4, the sudden increase in the effective lever arm length R of the pinion-side toothing 24, in the present case, for example, at least 60%, can occur during engagement of the tooth pair 28, 30 with extended pressure-side tooth flanks 28’, 30’. In the present case, the sudden increase in the effective lever arm length R thus begins, for example, at the sash opening angle of 60° (see Fig. 4a); R = 100%) and ends, for example, at the sash opening angle range of 70° (see Fig. 4b); R = 160%). The effective lever arm length R has therefore increased by 60% during the sudden increase between the sash opening angles of 60° and 70°. The tooth pair 28, 30 of the pinion-side and piston-side toothings 24 or 26 can engage with extended pressure-side tooth flanks 28’, 30’, particularly from a sash opening angle in the range of 60°.

Fig. 5 shows the tooth pair 28, 30 of the out-of-round rack and pinion gear 18 provided with extended pressure-side tooth flanks 28’, 30’ with the sash opening angle of 60° in an enlarged representation.

The rack and pinion gear 18 may also be designed such that the pinion 22 and the piston 16 can be driven in both directions.

In the various exemplary embodiments represented in the figures, at least one respective portion of the pinion-side toothing 24, with decreasing effective wing lever length R during opening of the sash, and a respective portion of the pinionside toothing 24. with re-increasing effective lever arm length R during opening of the sash, are produced at least partially by a profile shift varying accordingly when rolling over the rolling curve and/or a module varying accordingly when rolling over the rolling curve and/or flank angles varying accordingly when rolling over the rolling curve and/or radii of curvature of the tooth flanks of the pinion-side toothing 24 varying accordingly when rolling over the rolling curve.

The pressure-side tooth flanks 32 of the teeth 34 of the piston-side countertoothing 26, which engage with the pinion-side toothing 24 at sash opening angles in a sash opening angle range of about 60° to a maximum sash opening angle of particularly 180°, and particularly in the range of the maximum sash opening angle, each have a tooth flank angle a which is smaller than 20°, preferably smaller than 15°, wherein this tooth flank angle a in the present exemplary embodiment is, for example, 14° (see in particular Fig. 4a)).

The piston 16 of the drive 10 may be designed as a hollow piston with an internal toothing.

As shown in Fig. 3, the effective lever arm length R of the pinion side toothing 25 in the present exemplary embodiment drops by 50% in the initial sash opening angle range from 0° to the first predetermined sash opening angle of, for example, 30°, starting from the relatively higher lever arm length Ro at the sash opening angle of 0°, which corresponds here to the maximum effective lever arm length, with increasing sash opening angle. The effective lever arm length R of the pinionside toothing 25 with the sash opening angle of 30° thus corresponds to 50% of the lever arm length with the sash opening angle of 0° (Ro = 100%).

Fig. 7 shows a diagram, in which the course, that is dependent on the sash opening angle SOA, of the opening moment of a drive according to the invention with an abruptly dropping opening moment in an initial sash opening angle range and increased closing moments in the range from a sash opening angle of 70° (curve a)), is contrasted with that of a drive with a conventional rack and pinion gear (curve b)) and that of a conventional drive with a cam disk gear (curve c)).

As can be seen in particular from Fig. 6, the effective lever arm length R of the pinion-side toothing 25 in the present exemplary embodiment consistently corresponds to 80% of the maximum effective lever arm length with the sash opening angle of 0° from a sash opening angle of 90°.

As the diagram shows, the drive 10 or door closer according to the invention (see curve a)) exhibits a drop in the opening moment similar to that of cam disk gears, wherein at the same time a sufficient closing moment against wind loads, a higher efficiency, a high resistance to wear, improved opening damping properties and increased closing moments in the range from a sash opening angle 70° are achieved in order to produce a sufficient closing moment in all types of assembly.

Drive

Reference list

28’

30’

Ro

Housing

Spring unit

Piston

Rack and pinion gear

Output shaft

Pinion

Pinion-side toothing

Piston-side counter-toothing

Pinion-side tooth with extended pressure-side tooth flank

Extended pressure-side tooth flank

Piston-sided tooth with extended pressure-sided tooth flank

Extended pressure-side tooth flank

Pressure-side tooth flank

Piston-side tooth

First pressure-side tooth flank

Pinion-side tooth

Piston-side tooth

Line of action

Rolling curve

Centre line

Rolling curve increase

Effective lever arm length

Relatively higher, maximum effective lever arm length

Claims

1. A drive (10) for a sash of a door, a window or the like, having a housing (12), a piston (16) that is slidably guided in the housing (12) and acted on by a spring unit (14), and an output shaft (20) that is rotatably mounted in the housing (12) and connected with the piston (16) by a rack and pinion gear (18), wherein the rack and pinion gear (18) comprises an out-of-round pinion (22) connected to the output shaft (20), the toothing (24) of which meshes with a counter-toothing (26) on the piston side, and wherein the effective lever arm length (R) of the pinion-side toothing (24) decreases in an initial sash opening angle range of 0° to a first predetermined sash opening angle, starting from a relatively higher or maximum effective lever arm length (Ro) at the sash opening angle of 0°, with increasing sash opening angle and from a second predetermined sash opening angle, which is greater than or equal to the first predetermined sash opening angle and smaller than the maximum sash opening angle, increases abruptly with an increasing sash opening angle.

2. The drive according to any of the preceding claims, characterised in that a tooth pair (38, 40) of each of the pinion-side and piston-side toothings (24 and 26) that engage with one another in the initial sash opening angle range is designed such that, during opening of the sash, a horizontally extending, i.e. parallel to the direction of displacement of the piston (16) line of action (42) or one running relative to the horizontal or the direction of displacement of the piston (16), results.

3. The drive according to claim 2, characterised in that the horizontal or rising course of the line of action (42) of a pair of teeth (38, 40) of the pinion-side and piston-side toothings (24 or

26), which respectively engage with each other in the initial sash opening angle range, is at least partially produced by a profile shift varying accordingly when rolling over the rolling curve (44) and/or a module varying accordingly when rolling over the rolling curve (44) and/or flank angles varying accordingly when rolling over the rolling curve (44) and/or radii of curvature of the tooth flanks of the pinion-side toothing (24) varying accordingly when rolling over the rolling curve.

4. The drive according to any of the preceding claims, characterised in that the toothing (24) of the rack and pinion gear (18) is designed such that the effective lever arm length (R) of the pinion-side toothing (24) drops during opening of the sash, starting from an initial value with the wing closed at no more than a sash opening angle of 40°, preferably at no more than a sash opening angle of 30°, to at least 60%, preferably to at least 55% of the initial value.

5. The drive according to any of the preceding claims, characterised in that the first pressure-side tooth flank (36) of the pistonside counter-toothing (26), which engages with the pinion-side toothing (24) during opening of the sash, has a tooth flank angle (a) which is less than 25°, preferably less than 20°.

6. The drive according to any of the preceding claims, characterised in that the initial sash opening angle range preferably extends from 0° to a first predetermined sash opening angle in the range of 40°, preferably up to a first predetermined sash opening angle in the range of 30°.

7. The drive according to any of the preceding claims, characterised in that the effective lever arm length (R) of the pinion-side toothing (24) increases abruptly from a second predetermined sash opening angle in the range of about 60° to about 65°, preferably from 60°, with increasing sash opening angle.

8. The drive according to claim 7, characterised in that the effective lever arm length (R) of the pinion-side toothing (24) increases abruptly up to a sash opening angle in the range of 70°.

9. The drive according to at least one of the preceding claims, characterised in that the effective lever arm length (R) of the pinion-side toothing (24) continues to drop or at least remains substantially the same in the sash opening angle range between the first predetermined sash opening angle and the second predetermined sash opening angle.

10. The drive according to at least one of the preceding claims, characterised in that at least one engaging tooth pair (28, 30) of the pinionside and piston-side toothings (24 and 26) is provided with pressure-side tooth flanks that are extended in comparison with the pressure-side tooth flanks (28’, 30’) of the remaining tooth pairs for generating the abruptly increasing effective lever arm length (R) of the pinion-side toothing (24) or the associated rolling curve increase (48).

11. The drive according to at least one of the preceding claims, characterised in that the effective lever arm length (R) of the pinion-side toothing (24) increases by at least 40% due to its sudden increase, particularly by at least 60%.

12. The drive according to any of the preceding claims, characterised in that the sudden increase in the effective lever arm length (R) of the pinion-side toothing (24) occurs during engagement of the tooth pair (28, 30) with extended pressure-side tooth flanks (28’, 30’).

13. The drive according to any of the preceding claims, characterised in that the tooth pair (28, 30) of the pinion-side and pistonside toothings (24 or 26) engages with extended pressure-side tooth flanks (28’, 30’) from a sash opening angle in the range of 60°.

14. The drive according to any of the preceding claims, characterised in that at least one respective portion of the pinion-side toothing (24), with decreasing effective wing lever length (R) during opening of the sash, and a respective portion of the pinion-side toothing (24), with re-increasing effective lever arm length (R) during opening of the sash, are produced at least partially by a profile shift varying accordingly when rolling over the rolling curve and/or a module varying accordingly when rolling over the rolling curve and/or flank angles varying accordingly when rolling over the rolling curve and/or radii of curvature of the tooth flanks of the pinionside toothing (24) varying accordingly when rolling over the rolling curve.

15. The drive according to any of the preceding claims, characterised in that the toothing (24, 26) of the rack and pinion gear (18) is designed such that the pinion (22) and the piston (16) can be driven in both directions.

16. The drive according to any of the preceding claims, characterised in that the pressure-side tooth flanks (32) of the teeth (34) of the piston-side counter-toothing (26), which engage with the pinion-side toothing (24) at sash opening angles in a sash opening angle range of about 60° to a maximum sash opening angle of particularly 180°, and particularly in the range of the maximum sash opening angle, each have a tooth flank angle (a) which is smaller than 20°, preferably smaller than 15°

17. The drive according to any of the preceding claims,

5 characterised in that the piston (16) is designed as a hollow piston with an internal toothing.