WO2016026010A1

WO2016026010A1 - Braking system for braking a movement of a leaf of a sliding window or sliding door and the use of an activatable control unit in such a braking system

Info

Publication number: WO2016026010A1
Application number: PCT/BE2015/000037
Authority: WO
Inventors: Johan Andre Justine BERTE
Original assignee: Reynaers Aluminium, Naamloze Vennootschap
Priority date: 2014-08-22
Filing date: 2015-08-20
Publication date: 2016-02-25
Also published as: BE1022175B1

Abstract

Braking system (4) for braking a movement of a leaf (3) of a sliding window (1) or sliding door, whereby the braking system (4) has a first operating state in which the braking system (4) is active and a second operating state in which the braking system (4) is not active, whereby the braking system (4) comprises a control unit (13, 18, 36) that is arranged to, in the event of a movement of the leaf (3), bring the braking system (4) from the first operating state to the second operating state a specific time interval after passing a critical position.

Description

Braking system for braking a movement of a leaf of a sliding window or sliding door and the use of an activatable control unit in such a braking system.

The present invention relates to a braking system for braking a movement of a leaf of a sliding window or sliding door and the use of an activatable control unit in such a braking system.

It is desirable to be able to brake a leaf of a sliding window or sliding door when the leaf is moved at a higher speed than a critical speed.

This prevents injuries to limbs by these limbs being jammed between the leaf and a fixed frame and prevents damage to the sliding window or sliding door.

It is known to exert the braking force in such braking systems with a conventional compression spring. A catch is hereby provided that swings aside upon springing back after a braking movement, so that the brake then no longer operates and the leaf can be closed. This means that a first movement always has to be made, whereupon the leaf springs back, only after which can the leaf be closed.

The advantage of such systems is that they can be constructed compactly and can thereby easily be concealed in a frame. Alternative systems use a hydraulic spring or gas spring to brake the leaf. At a low speed such springs provide little or no resistance so that a normal closing movement is not hindered, while they brake the leaf at a high speed.

Such systems are described in EP 211462 and DE 10.2011.000166 for example.

The problem arises here that to be able to exert sufficient braking force on heavier leaves, such springs have to be made relatively thick so that they cannot be built in and are visually disruptive.

Such springs are also expensive, certainly in the embodiments that can provide relatively high braking forces .

The purpose of the present invention is to provide a solution to the aforementioned and other disadvantages by providing a braking system for braking a movement of a leaf of a sliding window or sliding door, whereby the braking system has a first operating state in which the braking system is active and a second operating state in which the braking system is not active, whereby the braking system comprises a control unit that is arranged to, in the event of a movement of the leaf, bring the braking system from the first operating state to the second operating state a specific time interval after passing a critical position. The specific time interval does not depend on the speed with which the leaf passes the critical position. Hereby the foregoing and further mentioned characteristics are in the mounted situation of the braking system.

This enables a braking operation to be obtained by the braking system that depends on whether or not the leaf exceeds a critical speed, in order to thereby obtain an unhindered movement of the leaf at low speeds, while at high speeds of the leaf it is nonetheless braked. This can be done by placing a coupling point of the braking system on the leaf at a certain distance from the critical position. The critical speed being exceeded is hereby equivalent to the leaf travelling the said distance within the said specific time interval. This means that by choosing the said distance and the specific time interval, a critical speed of the leaf, i.e. the transition point of the speed at which the leaf is or is not braked, can be adjusted. It is useful to note here that the essence of the invention lies in the braking operation not depending on the detection of the speed of the leaf, but on whether or not the leaf reaches the coupling point of the braking system on the leaf within the specific time interval.

By using such a control unit complete freedom is preserved to enable the braking force to be exerted by any means, so that the preconditions of the use of space and costs can be easily satisfied. In a preferred embodiment the control unit is provided with a mechanical, thus not electrical, component that defines the specific time interval. As a result the system does not require a power supply.

In a preferred embodiment the control unit is provided with a gas spring, preferably a gas pressure spring, that defines the specific time interval.

In a further preferred embodiment the braking system comprises a braking unit for exerting a braking force, whereby the braking unit has a part connected to a fixed point and a movable part, whereby the control unit and a first catch are connected to the movable part of the braking unit, whereby in the first operating state this first catch is in the path of travel of the leaf so that a braking force can be transmitted to a coupling point on the leaf, and whereby in the second operating state the first catch is not in the said path of travel or is in the said path of travel but can be pushed out of it by the leaf, whereby the control unit can be activated by an activation point on the leaf passing the critical position and whereby the control unit is arranged to, the specific time interval after activation of the control unit, remove the first catch from the said path of travel or remove a block that blocks the first catch in the said path of travel so that the first catch can be pushed away from the said path of travel by the leaf. As a result the braking system operates reliably because it must be actively taken out of its braked safe operating state .

The activation point can be a mechanical component of the leaf, but can also be done in another way, such as magnetically or optically defined for example.

If the speed of the leaf is greater than this critical speed, the first catch is still in the said path of travel at the moment that the coupling point is at the first catch, such that the leaf is braked.

If the speed of the leaf is less than this critical speed the first catch is already removed from the said path of travel at the time that the coupling point is at the first catch, such that the leaf can move further unhindered and can be closed.

The critical speed of the leaf can hereby be adjusted by placing the activation point and the coupling point at such a distance from one another on the leaf that the time, at the critical speed, between the activation of the control unit by the activation point and contact between the coupling point and the first catch corresponds to the specific time interval.

In a further preferred embodiment the braking system comprises a carrier part that is fastened to the leaf and which forms the said activation point and the said coupling point . The carrier part is so called because during the movement of the leaf it mechanically carries different components of the braking system with it during its movement or sets them in motion.

In a further preferred embodiment the control unit comprises a gas spring whose first end is fastened to the movable part of the braking unit and a second end is movable with respect to both the fixed point and the movable part of the braking unit, whereby the control unit can be activated by it being provided with means to release the second end from a tightened state of the gas spring as a result of the leaf passing the critical position.

A gas spring essentially consists of a cylinder and a movable piston therein. In a first variant, the cylinder forms the first end and the piston the second end, or in a second similar variant the piston the first end and the cylinder the second end. Such a gas spring, in a gas pressure spring embodiment, is tightened by moving both ends towards one another, thus compressing it.

Such a braking system uses the gas spring to remove the catch from the path of travel of the carrier element, after the specific time interval following the release of the gas spring from a tightened state.

This is possible because a gas spring has a relatively low speed with which it slackens. Because the gas spring only needs to have sufficient force to drive the first catch and not to brake the entire leaf, it is relatively cheap and also compact.

The braking force is hereby supplied by the braking unit on which there are no further requirements than to be able to supply the desired braking force, so that it can be constructed compactly and cheaply, for example as a steel spiral spring.

As a result the entire braking system can be made cheaply and compactly, while it satisfies the user desires for the optimum operation.

The invention also concerns a sliding window or sliding door that is provided with a fixed frame, a leaf and a braking system according to the invention, whereby the part of the braking unit connected to a fixed point is fastened to the fixed frame, whereby the carriage is movably mounted in the fixed frame and the coupling point and the first catch are fastened in such places that the coupling point can only rest against the first catch if the leaf is opened 50 cm or less, and preferably 20 cm or less.

As a result the braking system only operates at the last moment, when it is really necessary.

The invention also concerns the use of an activatable control unit, preferably provided with a gas spring, preferably a gas pressure spring, in a braking system for a leaf of a sliding window or sliding door for defining a specific time interval between the activation of the control unit and the placing of the braking system in a second operating state, in which the braking system is not active, from a first operating state in which the braking system is active.

With the intention of better showing the characteristics of the invention, a preferred embodiment of a braking system according to the invention is described hereinafter by way of an example, without any limiting nature, with reference to the accompanying drawings, wherein:

Figure 1 schematically shows a perspective view of a sliding window provided with a braking system according to the invention;

Figure 2 shows a cross-section according to line II-II of the window of figure 1;

Figure 3 shows the cross-section of figure 2, but in a perspective view, and with parts of the sliding window omitted;

Figure 4 shows the components of figure 2 in the same view as figure 2, but not as a cross-section;

Figures 5, 6 and 7 show the parts of figure 3 indicated by F5, F6 and F7 on a larger scale;

Figures 8 to 13 show different usage positions of the sliding window of figure 1 in a cross-section as shown in figure 2;

Figures 14 and 15 show an alternative embodiment of a sliding window that is provided with a braking system according to the invention, in a view that corresponds to figures 2 and 3 respectively; Figures 16 and 17 show the parts of figure 15 indicated by F16 and F17 on a larger scale; and

Figures 18 to 26 show different usage positions of the sliding window of figures 14 to 17, in a cross-section as in figure 14.

The sliding window 1 shown in the drawings comprises a fixed frame 2 and a slidable leaf 3.

Above the leaf 3 a braking system 4 is built into the frame 2 to brake a closing movement, i.e. a movement towards the left.

A carrier part 5, that has the form of a small block and which is mounted on the leaf 3, forms part of the braking system.

Because the leaf 3 can only be moved according to a specific path of travel in the frame 2, the carrier part 5 also has a fixed path of travel.

The braking system 4 has different operating states. Figures 2 and 7 show an operating state in which it is activated and ready for use.

The braking system 4 comprises a housing 7 for a braking unit that is firmly fastened to the fixed frame 3 and a spring is placed therein, in this example but not necessarily a tension spring 8, that is formed as a steel spiral and which acts as a braking unit. The tension spring 8 has two ends, i.e. a first end 9 and a second end 10. The first end 9 is fastened to the housing 7 and is thereby indirectly fastened to a fixed point.

The braking system 4 further comprises a carriage 12, that is shown further to the left in the said drawings. This carriage 12 is mounted slidably in the frame 2 and can be slid from left to right and back, thus in line with the direction in which the top part of the frame 2 extends. The carriage 12 is fastened to the movable second end 10 of the tension spring 8.

A gas pressure spring 13 is affixed in the carriage 12. In the situation shown this is compressed, thus tightened. The gas pressure spring 13 of course comprises a cylinder and a piston, that are not shown separately in the drawings however .

The end of the cylinder, hereinafter also termed the first end 14 of the gas pressure spring 13, is fastened firmly to the carriage 12. Two arms 16 are fastened at the end of the piston, hereinafter also termed the second end 15 of the gas pressure spring 13. These arms 16 extend horizontally and are at a distance from one another.

A pivoting hook 18 is rotatably suspended between the two arms 16 by means of a first shaft 19. This pivoting hook 18 is provided with a spring (not shown) that exerts a rotational force on the pivoting hook 18 in the anticlockwise direction. The arms 16 and the pivoting hook 18 are connected to the second end 15 of the gas pressure spring 13 and are thus not firmly connected to the carriage 12, but can move with this second end 15 in the carriage 12.

In the situation shown there is a clasp 21, close to the end 20 of the arms 16, that can pivot vertically by means of a second shaft 22. A third shaft 23 is affixed on the clasp 21 that is not fastened to the carriage 12 and thus moves with the clasp 21.

In the position shown, also termed the first position, the third shaft 23 is in the path of travel of the carrier part 5, so that this third shaft 23 forms a first catch for the carrier part 5.

This first position of the clasp 21 is simply adopted under the influence of gravity. A spring can also be provided to preferably place the clasp 21 in the first position.

The pivoting hook 18 is provided with a part, to the left in the drawings, that acts as a cam 25 that can be pushed away by the carrier part 5. On the right-hand side the pivoting hook 18 is provided with a second hook-shaped catch 26 for the carrier part 5. In the position shown, also termed the first position, this second catch 26 is not in the path of travel of the carrier part 5, but will, as will be explained later, be in that path of travel in other usage states of the braking system. On its top the pivoting hook 18 is provided with a rectangular pawl 27, which, as is especially clear in figure 6, is in a cutaway 28 in the top wall 29 of the carriage 12, and thereby forms a latch that blocks the second end 15 of the gas pressure spring 13 and the components connected thereto, so that the gas pressure spring 13 remains in a tightened state.

The operation of the braking system 4 is simple and as follows. It is illustrated on the basis of figures 8 to 13.

Hereby two separate situations are shown, i.e. in figures 8 to 11 a situation in which the leaf 3 is closed slowly, i.e. more slowly than a critical speed, and then opened again, and in figures 12 and 13 a situation in which the leaf 3 is closed faster than the said critical speed.

In these drawings, for the purpose of clarity the tension spring 8 and its housing 7 are shown rather schematically compared to figure 2.

Figure 8 shows the sliding window 1 during a closing movement of the leaf 3 just before the moment that the cam 25 of the pivoting hook 18 touches the carrier part 5.

Figure 9 shows the sliding window 1 during the same closing movement of the leaf, after the cam 25 of the pivoting hook 18 has touched the carrier part and has been pushed upwards . As a result of the cam 25 being pushed upwards, the following actions occur successively.

The pivoting hook 18 rotates towards a second position, such that the pawl 27 is removed from the cutaway 28. The latch or block of the gas pressure spring 13 is thereby removed so that this gas pressure spring 13 will slacken and the second end 15 and the arms 16 and pivoting hook 18 attached thereto are pushed away towards the left in the drawings with respect to the carriage 12.

The second catch 26 on the pivoting hook 18 is brought into the path of travel of the carrier part 5, but behind the carrier part 5.

The ends 20 of the arms 16 hereby push against the clasp 21 so that the clasp 21 is tilted upwards towards a second position and thereby the first catch 23 is removed from the path of travel of the carrier part 5 as the carrier part 5 is still some distance from this first catch 23, as shown in figure 9.

The pawl 27 on the pivoting hook 18 is hereby pushed against the top wall 29 of the carriage, such that the pivoting hook 18 cannot go back to its first position.

The leaf 3 can now be further closed unhindered, as shown in figure 10.

If the leaf 3 is now opened again, as shown in figure 11, the carrier part 5 is pushed against the second catch 26, such that the gas pressure spring 13 is tightened again. At the same time the clasp 21 comes back to its first position. If the pawl 18 is again opposite the cutaway 28 in the top wall 29 of the carriage 12, it will fall therein, such that the pivoting hook 18 is again moved to its first position and the gas pressure spring 13 is again blocked in its tightened position.

The carrier part 5 is now no longer in contact with the second catch 26 so that the leaf 3 can be opened further unhindered. In the situation in which the leaf 3 is closed quickly, as shown in figure 12, the same happens in relation to the pivoting hook 18 as with the slow movement described earlier . However, at the time that the carrier part 5 is under the clasp 21, the distance over which the arms 16 have moved is still too small to bring the clasp 21 to its second position. In other words, within the time that the gas pressure spring 13 needs to bring the clasp 21 to its second position, the carrier part 5 has come to the first catch 23 due to the high speed of the leaf. As a result the first catch 23 is still in the path of travel of the carrier part 5, such that this first catch 23 is taken along with the carrier part 5.

The entire carriage 12 now slides in the frame, under the tightening of the tension spring 8, that thereby exerts a braking force on the leaf 3 via the carriage 12, as shown in figure 13 and brakes and pushes back this leaf 3.

During this return movement the clasp 21 is still tilted towards its second position, such that a second closing movement of the leaf 3 can be performed without braking force .

In other words the braking system 4 has a first operating state in which it is active, i.e. it brakes the leaf, and a second operating state in which it is not active.

The pivoting hook 18 and the gas pressure spring 13 hereby operate as a control unit to place the braking system 4 in the first or second operating state during a movement of the leaf 3, whereby it depends on the speed of travel of the leaf 3 and more specifically the position of the carrier part 5 at the time that the braking system 4 changes operating state, or during its movement the carrier part 5 encounters a braking system 4 in the first or the second operating state and thus is or is not braked.

The carrier part 5 hereby thus forms a coupling point for the braking force, that is exerted by the tension spring 8 by means of the carriage 12 and the first catch 23, and an activation point for activating the control unit.

The opening of the leaf 3 again proceeds as described above .

It goes without saying that a guide has to be provided in the frame 2 to enable a movement of the carriage 12. By making the carriage 12 somewhat longer than shown in the drawings and by letting it drop around the housing 7 of the tension spring 8, this housing 7 partially acts as a guide.

A slotted hole 30 is also indicated that can be affixed around a guide pawl.

In general terms the operation of the braking system is essentially based on the fact that a gas spring needs a certain discrete and relatively constant time to slacken. This slackening is much slower and more controlled than a steel spiral spring.

As a result there is a specific time interval between pushing the cam 25 upwards and pushing the clasp 21 upwards with the first catch 23.

This enables a critical speed of the leaf to be defined, whereby this critical speed is set in the braking system by the unlatching of a block of the gas spring and a removable catch as a result of the slackening of the gas spring at a certain distance from each other. Figures 14 to 26 show an alternative embodiment. This alternative embodiment has the following differences to the embodiment described above:

The braking unit is constructed as a compression spring 31 that is mounted with its first end 9 against a housing 7, and which has a second end 10 on which a connecting rod 32 is mounted, which in turn is mounted on the carriage 12.

The components that are in the carriage 1 are generally different .

The first catch is constructed as a vertical tiltable hook

33 that is part of a hook body 34, whereby this hook body

34 is fastened to the carriage by means of a fourth shaft 35. A first end 14 of a gas pressure spring 13 is fastened to the opposite side of the hook body 34. The second end 15 of this gas pressure spring 13 is fastened to an actuator 36.

The actuator 36 is constructed in two parts, whereby both parts 37, 38 are hingeable with respect to one another. The gas pressure spring 13 is fastened to the first part 37 of the actuator 36, and the second part 38 of the actuator is above the hook 33.

The actuator 36 can be moved essentially horizontally. However, the first part 37 of it can also be moved vertically due to the hingeability of the actuator 36. On the inside of the carriage this is constructed with an upright edge 39 for guiding a movement of the actuator 36. This upright edge 39 enables a free movement of the head 40 of the first part 37 of the actuator 36 above the upright edge 39, but prevents a movement of the head 40 to below the edge 39.

In contrast to the embodiment described above, a block- shaped carrier part 5 is not mounted on the leaf 3.

As described below, in this case the corner 42 of the frame of the leaf 3 acts as a coupling point for braking forces and as an activation point for the braking system 4. Of course reinforcement pieces can be affixed to the leaf 3, if this is necessary, to accommodate the forces concerned.

Alternatively of course, just as with the first embodiment, such a carrier part can indeed be mounted. The operation of this alternative embodiment is as follows, and shown in figures 18 to 26.

The description starts with a practically closed leaf 3, such as in figure 18, that is opened as shown in figure 19.

The head 40 hereby slides over the top edge of the leaf. As soon as the corner 42 of the leaf 3 has passed the head 40 of the actuator 36, the head 40 moves, and thereby the entire first part 37 of the actuator 36, downwards until its downward movement is stopped by the upright edge 39. Figures 20 to 24 now show a succession of situations that arise when the leaf 3 is closed more slowly than a critical speed. As shown in figure 20, the head 40 of the actuator 36 now acts as a catch for the leaf 3. As a result the gas pressure spring 13 is tightened and the hook 33 is tilted downwards by the second part 38 of the actuator 36, so that it is in the path of travel of the leaf 3.

At the same time the actuator 36 is pushed to the left, so that the second part 38 of the actuator 36 is above the hook body 34 and blocks this hook body 34, in other words prevents the hook 33 from being able to tilt upwards.

At the same time due to the upright edge 39, as a result of the movement to the left, the first part 37 of the actuator 36 is pushed upwards, until the leaf is no longer pushed against the head 40 of the actuator 36. This is shown in figure 21.

This is a critical position of the leaf 3, as as of the moment that the corner 42 of the leaf 3 has passed this position, the gas pressure spring 13 is released and the tightened gas pressure spring 13 pushes the actuator 36 to the right at a specific speed.

Such a situation is shown in figure 22. The braking system 4 is now still in an active first operating state in which the hook 33 is in the path of travel of the leaf 3 and is blocked by the actuator 36. With the further movement of the actuator 36, at a given moment it again comes to the situation of figure 19, so that a second operating state occurs in which the hook 33 is no longer blocked by the second part 38 of the actuator 36, so that the hook 23 can freely tilt upwards and can no longer exert an effective braking force on the leaf 3, and in which the braking system 4 is thus no longer active.

The actuator 36, in particular with its head 40, and the gas pressure spring 13 hereby operate as a control unit to place the braking system 4 from the first to the second operating state, a specific time interval after the control unit has been activated by the corner 42 of the leaf 3 passing the critical position.

If the leaf 3 now comes against the hook, as shown in figure 23, the hook 33 is tilted upwards and the leaf 3 moves further to the left unhindered, as shown in figure 24, and further to a closed position.

If the leaf 3 moves faster than the critical speed, the actuator 36 will still be above the hook body 34 at the time that the corner 42 of the leaf 3 touches the hook 33. The hook 33 thereby remains blocked in the path of travel of the leaf 3, so that the hook 33 acts as a first catch for the leaf 3. This is shown in figure 25.

As a result the leaf 3 sets the entire carriage 12 into motion. This motion is transmitted via the connecting rod 32 to the compression spring 31 that thereby tightens and brakes the leaf. This is shown in figure 26.

In this embodiment, the gas pressure spring 13 is always in a slightly tightened state, even in its most slackened state, as shown in figure 18. As a result the head 40 is always actively pushed downwards, and the good operation of the braking system thus does not depend on gravity. This also ensures that the hook 33 is kept in its top position, as shown in figure 19, because the fastening of the gas spring 13 to the hook body 34 is at such a position with respect to the fourth shaft 35 that, between the situation in figure 19 and the situation in figure 20, the hook body 34 must be brought past a neutral point against the slackening direction of the gas spring 13.

Alternatively in the above embodiments the speed detection of the leaf can also be implemented electronically.

The present invention is by no means limited to the embodiments described as an example and shown in the drawings, but a braking system according to the invention can be realised in all kinds of forms and dimensions without departing from the scope of the invention.

Claims

1. - Braking system (4) for braking a movement of a leaf (3) of a sliding window (1) or sliding door, whereby the braking system (4) has a first operating state in which the braking system (4) is active and a second operating state in which the braking system (4) is not active, whereby the braking system (4) comprises a control unit (13, 18, 36) that is arranged to, in the event of a movement of the leaf (3), bring the braking system (4) from the first operating state to the second operating state a specific time interval after passing a critical position.

2. - Braking system (4) according to claim 1, characterised in that the control unit (13, 18, 36) is provided with a mechanical component (13) that defines the specific time interval .

3. - Braking system (4) according to claim 1, characterised in that the control unit (13, 18, 36) is provided with a gas spring (13) that defines the specific time interval.

4. - Braking system (4) according to any one of the previous claims, characterised in that the braking system (4) comprises a braking unit (8, 31) for exerting a braking force, whereby the braking unit (8, 31) has a part connected to a fixed point (9) and a movable part (10), whereby the control unit and a first catch (23, 33) are connected to the movable part (10) of the braking unit (8, 31) , whereby in the first operating state this first catch (23,33) is in the path of travel of the leaf (3) so that a braking force can be transmitted to a coupling point (5) on the leaf (3) and whereby in the second operating state the first catch (23,33) is not in the said path of travel, or is in the said path of travel but can be pushed away from it by the leaf (3), whereby the control unit (13, 18, 36) can be activated by an activation point (5) on the leaf (3) passing the critical position and whereby the control unit

(13, 18, 36) is arranged to, the specific time interval after activation of the control unit (13, 18), remove the first catch (23,33) from the said path of travel or remove a block that blocks the first catch (23,33) in the said path of travel so that the first catch (23,33) can be pushed out of the said path of travel by the leaf (3) .

5.- Braking system according to claim 4, whereby the control unit comprises a gas spring (13) of which a first end (14) is fastened to the movable part (10) of the braking unit (8, 31) and a second end (15) is movable with respect to both the fixed point and the movable part (10) of the braking unit (8, 31), whereby the control unit (13, 18, 36) is activatable because it is provided with means to release the second end (15) from a tightened state of the gas spring (13) as a result of the leaf (3) passing the critical position.

6.- Braking system (4) according to claim 5, characterised in that it is arranged to be in the first operating state if the gas spring (13) is tightened

7. - Braking system (4) according to any one of the previous claims, whereby in the first operating state a hook (33) that is connected to a braking spring (31) is blocked in the path of travel of the leaf (3) and in the second operating state the hook (33) is not in, or can freely tilt away from, that path of travel, whereby the braking system (4) is provided with an actuator (36) that is coupled to a gas pressure spring (13) and which acts as a catch (40) for the leaf (3) to compress the gas pressure spring (13) by a closing movement of the leaf (3) , whereby the braking system (4) is provided with a guide (39) for the actuator (36) such that the actuator (36) is removed from the path of travel of the leaf (3) if the leaf (3) is in the critical position so that the actuator (36) can no longer act as a catch, whereby the actuator (36) does not block the hook (33) in a situation in which the gas pressure spring (13) is slackened, and whereby the actuator (36) does block the hook (33) in a situation in which the gas pressure spring (13) is entirely or partially tightened.

8. - Braking system according to claim 7, whereby the actuator (36) is movable above the hook (33) between a carriage (12) and the hook (33), and blocks the hook (33) due to its presence above the hook (33) .

9. - Braking system (4) according to claim 5 or 6, characterised in that the control unit (13, 18) can be activated by it being provided with a latch removable by the activation point (5) that is arranged to block the second end (15) of the gas spring (13) in a tightened state of the gas spring (13) with respect to the movable part (10) of the braking unit (8) , and to release the second end

(15) of the gas spring (13) when removing the latch, whereby the braking system (4) is arranged such that the first catch (23) is pushed out of the said path of travel by means of the second end (15) of the gas spring (13) during a slackening of the gas spring (13) .

10. - Braking system (4) according to claim 9, characterised in that the braking system (4) comprises a carriage (12) that is slidable with respect to the fixed point and which is connected to the movable part (10) of the braking unit (8), whereby the first catch (23) is connected to the movable part (10) of the braking unit (8) via the carriage

(12) , whereby the first end (14) of the gas spring is firmly fastened to the carriage (12) and the removable latch is arranged to block the second end (15) of the gas spring (13) in a tightened state of the gas spring (13) with respect to the carriage (12) .

11. - Braking system (4) according to claim 9 or 10, characterised in that the first catch (23) forms part of a vertically tiltable clasp (21), whereby the second end (15) of the gas spring (13) is provided with at least one arm

(16) that is arranged, during slackening of the gas spring

(13) , to push against the clasp (21) to thereby place the first catch out of the said path of travel.

12. - Braking system (4) according to any one of the claims 4 to 11, characterised in that it comprises a carrier part (5) that is fastened to the leaf (3) and that it forms the said activation point.

13. - Braking system (4) according to claim 12, characterised in that the carrier part (5) also forms the said coupling point.

14. - Sliding window (1) or sliding door, that is provided with a fixed frame (2), a leaf (3) and a braking system (4) according to any one of the previous claims.

15. - Sliding window (1) or sliding door according to claim

14, that is provided with a fixed frame (2), a leaf (3) and a braking system (4) according to any one of the claims 6 to 14, whereby the part connected to a fixed point (9) of the braking unit (8) is fastened to the fixed frame (2) and whereby the carriage (12) is slidably mounted in the fixed frame (2) .

16. - Sliding window (1) or sliding door according to claim

15, characterised in that the coupling point (5) and the first catch (23,33) are fastened in such places that the coupling point (5) can only rest against the first catch (23,33) if the leaf (3) is open 50cm or less.

17. - Usage, in a braking system (4) for braking a movement of a leaf (3) of a sliding window (1) or sliding door, of an activatable control unit (13, 18, 36) for defining a specific time interval between the activation of the control unit (13, 18, 36) and the placing of the braking system (4) in a second operating state in which the braking system is not active, from a first operating state in which the braking system (4) is active.

18. - Usage according to claim 17, characterised in that the control unit (13, 18, 36) comprises a mechanical component

(13) for defining the specific time interval.

19. - Usage according to claim 17 or 18, characterised in that the mechanical component (13) can move at a reference speed such that, in combination with a given distance, the specific time interval is defined.

20. - Usage according to any one of the claims 17 to 19, characterised in that the mechanical component is a gas spring (13) .